domain: chim chim

text:
Mélanie François
email: melanie.francois@u-bourgogne.fr

Frédéric Demoisson

Mohamed Sennour

Gilles Caboche

Continuous hydrothermal synthesis in supercritical conditions as a novel process for the elaboration of Y-doped BaZrO3

Keywords: Hydrothermal synthesis, Protonic Ceramic Fuel Cell, Nanoparticles, Supercritical water, Y-doped BaZrO3

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Finding new clean and efficient ways to generate energy has become a major global challenge.

For a few years now, Protonic Ceramic Fuel Cells (PCFCs) have attracted much attention in the field of hydrogen energy. Contrary to Solid Oxide Fuel Cells that operate at a temperature above 600 °C and where the oxygen ions are the charge carriers, PCFCs use protons. Indeed, the lower activation energy of proton diffusion compared to that of the oxygen ion allows to decrease the operating temperature down to the 400 -600 °C range [START_REF] Meng | Review: recent progress in low-temperature proton-conducting ceramics[END_REF]. Among the different electrolyte materials for PCFCs, BaCeO3 and BaZrO3 have attracted much attention [START_REF] Hossain | A review on proton conducting electrolytes for clean energy and intermediate temperature-solid oxide fuel cells[END_REF][START_REF] Nowick | High-temperature protonic conductors with perovskite-related structures[END_REF][START_REF] Dai | Electrochemical performance of protonic ceramic fuel cells with stable BaZrO3-based electrolyte: A mini-review[END_REF].

BaCeO3-based oxides are currently the most commonly chosen electrolyte material for PCFC [START_REF] Xu | Proton-conducting electrolyte materials[END_REF][START_REF] Bi | Fabrication and characterization of easily sintered and stable anode-supported proton-conducting membranes[END_REF]. It is generally reported that doped-BaCeO3 exhibits the highest protonic conductivity among the perovskite-type materials [START_REF] Kreuer | Proton-Conducting Oxides[END_REF][START_REF] Ryu | Chemical stability and proton conductivity of doped BaCeO3-BaZrO3 solid solutions[END_REF][START_REF] Wang | Further optimization of barium cerate properties via co-doping strategy for potential application as proton-conducting solid oxide fuel cell electrolyte[END_REF]. However, BaCeO3-based perovskites exhibit low stability in H2O and/or CO2 containing atmosphere which limits their practical application [START_REF] Matsumoto | Relation Between Electrical Conductivity and Chemical Stability of BaCeO[sub 3]-Based Proton Conductors with Different Trivalent Dopants[END_REF][START_REF] Münch | Proton diffusion in perovskites: comparison between BaCeO3, BaZrO3, SrTiO3, and CaTiO3 using quantum molecular dynamics[END_REF]. On the contrary, doped BaZrO3 exhibits excellent chemical stability [START_REF] Kim | Study on the chemical stability of Y-doped BaCeO3-δ and BaZrO3-δ films deposited by aerosol deposition[END_REF]. The substitution of zirconium by yttrium allows to achieve acceptable electrical conductivity up to 10 -3 S.cm -1 [START_REF] Fabbri | Towards the Next Generation of Solid Oxide Fuel Cells Operating Below 600 °C with Chemically Stable Proton-Conducting Electrolytes[END_REF][START_REF] Yun | Structural and Electrochemical Properties of Dense Yttria-Doped Barium Zirconate Prepared by Solid-State Reactive Sintering[END_REF]. However, the highly refractive nature of BaZr1-xYxO3-δ (noted BZY) leads to the requirement of a high synthesis temperature (1400 °C) for the classical solid state reaction method and to an even higher (1600 -1700 °C) sintering temperature [START_REF] Bi | Synthesis strategies for improving the performance of doped-BaZrO 3 materials in solid oxide fuel cell applications[END_REF][START_REF] Loureiro | A review on sintering technology of proton conducting BaCeO3-BaZrO3 perovskite oxide materials for Protonic Ceramic Fuel Cells[END_REF].

In this work, a continuous hydrothermal process developed at the ICB laboratory is proposed to elaborate the electrolyte material [START_REF] Aymes | Counter-current flow reactor with heat transfer for hydrothermolytic synthesis[END_REF]. The supercritical hydrothermal synthesis of metal oxide particles using a continuous flow reactor was first proposed by Adschiri et al. in 1992 [18]. This process presents several advantages such as a precise control of the morphology and the size of the particles with a narrow size distribution [START_REF] Demoisson | Hydrothermal Synthesis of ZnO Crystals from Zn(OH) 2 Metastable Phases at Room to Supercritical Conditions[END_REF][START_REF] Pighini | Low-frequency Raman characterization of size-controlled anatase TiO2 nanopowders prepared by continuous hydrothermal syntheses[END_REF][START_REF] Philippot | Insights into BaTi1-yZryO3 (0 ≤ y ≤ 1) Synthesis under Supercritical Fluid Conditions[END_REF]. Furthermore, in supercritical water, inorganic compounds become insoluble leading to the formation of hydroxide nuclei which are immediately dehydrated to form ultrafine particles [START_REF] Demoisson | Influence of the pH on the ZnO nanoparticle growth in supercritical water: Experimental and simulation approaches[END_REF]. Another important advantage of using supercritical water with a continuous flow is the short reaction time leading to the possible formation of metastable and highly doped structures [START_REF] Zhu | Highly Cr-Substituted CeO 2 Nanoparticles Synthesized Using a Non-equilibrium Supercritical Hydrothermal Process: High Oxygen Storage Capacity Materials Designed for a Low-Temperature Bitumen Upgrading Process[END_REF][START_REF] Yoko | Continuous Flow Synthesis of Nanoparticles Using Supercritical Water: Process Design, Surface Control, and Nanohybrid Materials[END_REF].

The synthesis of BaZrO3 by the continuous hydrothermal process was investigated by several groups in the past decade. For example, Aimable et al. studied the influence of the nature of the precursors, the pH and the temperature on the synthesis of BaZrO3 [START_REF] Aimable | Continuous hydrothermal synthesis of nanometric BaZrO3 in supercritical water[END_REF]. Yoko et al. studied the formation mechanism of BaZrO3 in supercritical water. They suspected the formation of Ba-deficient particles with a shell of ZrO(OH) at the early stage of the precipitation followed by an uptake of Ba 2+ up to Ba/Zr=1 [START_REF] Yoko | Formation mechanism of barium zirconate nanoparticles under supercritical hydrothermal synthesis[END_REF]. In 2016, the same group used in situ X-ray diffraction to study and support the previous mechanism [START_REF] Yoko | In situ X-ray diffraction for millisecond-order dynamics of BaZrO 3 nanoparticle formation in supercritical water[END_REF].

However, few studies focus on doped BaZrO3 material elaborated by this method, and, to the authors' knowledge, no studies on Y-doped BaZrO3 have been conducted. Then, this work aims to investigate the feasibility of the elaboration of BaZr1-xYxO3-δ by supercritical hydrothermal process using a continuous flow reactor.

Materials and Methods

Continuous process

The continuous process can be used up to 600 °C/35.0 MPa. Indeed, for water, the critical temperature/critical pressure values are 374 °C/22.1 MPa, this set-up can work in supercritical conditions. For the experiments, the syntheses were carried out at 410 °C/30.0 MPa. A solution of metallic precursors (Ba(NO3)2, ZrO(NO3)2‧6H2O and Y(NO3)3‧6H2O purchased from Sigma-Aldrich) is prepared by following the stoichiometry of the target composition by dissolution in deionized water and homogenized with an ultrasonic rod, the concentration is 5×10 -2 mol L -1 for Ba 2+ , 4×10 -2 mol L -1 for Zr 4+ and 1×10 -2 mol L -1 for Y 3+ . A second solution composed of sodium hydroxide at 3×10 -1 mol L -1 was employed in order to avoid the formation of ZrO2 [START_REF] Aimable | Continuous hydrothermal synthesis of nanometric BaZrO3 in supercritical water[END_REF]. Figure 1 shows the scheme of the continuous set-up. Container (a), at the beginning of the process, holds the aqueous solution of metal cations, container (b) holds the solution of sodium hydroxide and the third container (c) holds the distilled water. The reactor consists of a "pipe to pipe" cylinder with a total volume of 25 mL, the inner diameter of the external pipe is 10 mm. Pressurized solutions (a) and (b) are brought to the reactor inlet at room temperature by high-pressure pumps. Pressurized demineralized water is pre-heated and brought counter-currently through the internal pipe of the reactor so that the three solutions meet at the mixing zone. The resulting solution is evacuated through the external pipe where the reactions leading to the formation of metal oxides take place.

The flow rate of the three solutions is set to around 10 mL min -1 per solution, the final flow measured at the end of the set-up (after the back pressure regulator) varies between 30 and 35 mL.min -1 . The residence time into the reactor under supercritical conditions is of the order of few seconds (determined by Computational Fluid Dynamics calculations) [START_REF] Demoisson | Design of a reactor operating in supercritical water conditions using CFD simulations. Examples of synthesized nanomaterials[END_REF]. At the reactor outlet, a cooling system stops the germination and growth stages. A filtration system at the end of the device captures the agglomerated particles that are added to the suspension obtained after the back-pressure regulator. The particles sediment at the bottom of the beaker, the surfactant is siphoned off and distilled water is added to wash the particles. This operation is repeated until a neutral pH is obtained. The supernatant water is siphoned off one last time and the suspension is dried in an oven at 80 °C for three days to obtain a powder.

Characterization methods

X-Ray Diffraction (XRD) analysis was conduct on a Bruker D2 Phaser coupled with linear detector Lynxeye_XE_T using Cu Kα radiation. The obtained XRD pattern was refined by the Rietveld method using the Fullprof software. The microstructure was investigated by transmission electron microscopy (TEM) on a ThermoFisher FEI Tecnai F20. The chemical composition was analyzed by scanning electron microscopy (SEM) on a Hitachi SU1510 coupled with a Bruker XFlash6I10 energy-dispersive X-ray (EDX) analyzer. The collected peaks for EDX quantification were the L-series of Ba, Zr and Y and the K-series of O. EDX investigations were conducted on 16 different agglomerates with an area of measurement from 2.5 µm × 2.5µm to 5µm × 5 µm. The Brunauer, Emmett and Teller (BET) measurement was carried out on a Micromeritics TriStar 3020.

Particle size distribution (PSD) was evaluated using the Dynamic Light Scattering method using Mie theory calculation with a Malvern Microsizer 2000 laser granulometer coupled with a hydro 2000MU dispersion unit using ultrasound.

Results and discussion

Among the Y-doped BaZrO3 materials, BaZr0.8Y0.2O3-δ appears to be the best composition. The protonic conductivity increases with the Y content up to a substitution of 20 % before decreasing due to structural distortion and proton trapping [START_REF] Han | Chemical Expansion of Yttrium-Doped Barium Zirconate and Correlation with Proton Concentration and Conductivity[END_REF][START_REF] Fabbri | Does the increase in Y-dopant concentration improve the proton conductivity of BaZr1-xYxO3-δfuel cell electrolytes?[END_REF]. Thus, BaZr0.8Y0.2O3-δ was the target composition. The chemical reaction yield varies from 60.5 % to 70 % with an average value of 66.5 %, the productivity depends on the final flow measured after the back pressure regulator and varies from 5.5 to 6.8 g.h -1 , about 23.5 g was produced per synthesis. suggesting that the elementary grains are highly agglomerate. Figure 3 shows the TEM micrograph of the synthesized powder. As suggested by the PSD analysis, the particles with a nearly spherical morphology are agglomerated. The particle size varies from 10 nm to 315 nm on this micrograph with a median value of 48 nm (evaluation on 50 particles).

The X-ray diffractogram of the obtained powder is shown in Figure 4. The major phase obtained has a perovskite cubic structure with Pm-3m space group. BaCO3, with an orthorhombic Pnma structure, and YO(OH), with a monoclinic P21/m structure as secondary phases were detected. Rietveld refinement was performed on the diffractogram, the determined phase percentages are 86.2, 10.6 and 3.1 wt% for BZY, BaCO3 and YO(OH) respectively. The average crystallite size of the perovskite phase was evaluated from the integral width of the diffraction peaks and is 53 nm. This value is in agreement with the 48 nm obtained from TEM analysis and with the 47.3 ± 0.2 nm calculated from the 20.74 ± 0.06 m² g -1 specific surface area obtained by BET measurement. The refined lattice parameter for the perovskite cubic phase is 4.2015 Å, this value is lower than those reported in the literature for BaZr0.8Y0.2O3-δ suggesting that a part of Y is not in the perovskite phase leading to the formation of YO(OH). [START_REF] Nuñez | Preparation of Y-Doped BaZrO3 Proton Conducting Solid Electrolyte via Modified Low Temperature Pechini Method[END_REF][START_REF] Akbarzadeh | Combined theoretical and experimental study of the low-temperature properties of BaZrO 3[END_REF]. Then, this synthesis method does not appear to particularly generate defects or nano-size effects that affect the lattice parameter. Moreover, the increase in the lattice parameter for Y-doped BaZrO3 compared to the non-doped sample well evidence the Y doping. However, the amount of Y cannot be quantified by XRD since the synthesis route implement several defects or structural distortions that affect the lattice parameter value, for example, values of lattice parameter for BaZr0.9Y0.1O3-δ differ from 4.193 Å to 4.2101 Å [START_REF] Sažinas | Effect of CO 2 Exposure on the Chemical Stability and Mechanical Properties of BaZrO 3 -Ceramics[END_REF][START_REF] Hoedl | Impact of point defects on the elastic properties of BaZrO3: Comprehensive insight from experiments and ab initio calculations[END_REF][START_REF] Duval | Characterisation of BaZr 0.9 Y 0.1 O 3-δ Prepared by Three Different Synthesis Methods: Study of the Sinterability and the Conductivity[END_REF][START_REF] Schober | Water vapor solubility and electrochemical characterization of the high temperature proton conductor BaZr0.9Y0.1O2.95[END_REF][START_REF] Tsvetkov | Thermoelectric Behavior of BaZr0.9Y0.1O3-d Proton Conducting Electrolyte[END_REF].

In order to determine the composition of the BZY powder as-synthesized, EDX investigations were conducted on several agglomerates. Ba, Zr, Y and O elements were detected, for the following interpretation, Ba is assumed to belong to the A-site of the perovskite while Zr and Y are supposed to occupy the B-site of the perovskite. Figure 5 shows a) the obtained A-site/B-site ratios and b) the obtained Y/(Zr+Y) ratios and the corresponding number of agglomerates per interval. The as-synthesized powder exhibits a wide range of A-site/B-site ratio, from 0.70 to 1.33, with a strong tendency for the Ba-deficient composition. In order to homogenize the composition, a heat treatment at 1000 °C for 1 hour was applied to the powder. The resulting distribution of A-site/B-site ratio is narrower, the lower value is 0.92 and the biggest value is 1.08 with an average value equal to 1.01. Then, the thermal treatment at 1000°C effectively homogenizes the composition. Moreover, a study of Haile group showed that BaCO3 decomposition leads to the compensation of the Ba sub-stoichiometry during sintering [START_REF] Yamazaki | High Total Proton Conductivity in Large-Grained Yttrium-Doped Barium Zirconate[END_REF]. Since BaCO3 decomposition (reaction 1) occurs at around 1000 °C [START_REF] Arvanitidis | A Study of the Thermal Decomposition of BaC03[END_REF], it can reasonably be assumed that the increase of the A-site/B-site ratio in the annealed powder is due to the Ba uptake from BaCO3. The integration of Ba in the BZY structure is described in Kröger -Vink notation in reaction 2.

→ + Reaction 1 + + •• → × + × Reaction 2
The Y/(Zr+Y) ratio values of the as-synthesized powder cover an interval of 0.08 to 0.25 with an average value of 0.14, this ratio is lower than the expected 0.20. Yamazaki et al. and Magrez et al.

have shown that yttria exsolution in Ba-deficient BZY compounds during sintering is due to the Ba sub-stoichiometry [START_REF] Yamazaki | Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure, and proton conductivity[END_REF][START_REF] Magrez | Preparation, sintering, and water incorporation of proton conducting Ba0.99Zr0.8Y0.2O3Àd: comparison between three different synthesis techniques[END_REF]. It can then be assumed that, in hydrothermal synthesis, the Ba-deficiency caused by the kinetics of the BaCO3 formation faster than the BZY formation hinders the incorporation of more than 14 % of Y in the BZY structure. After thermal treatment, the distribution of Y/(Zr+Y) is substantially the same as before, covering an interval from 0.07 to 0.24 with an average value of 0.15. Because of the high occupancy rate of the B-site of the perovskite, yttrium from YO(OH) cannot integrate the perovskite structure and react at 450 °C to form Y2O3 according to reaction 3 [START_REF] Sato | Thermal transformation of yttrium hydroxides to yttrium oxides[END_REF]:

2 ( ) → + Reaction 3

Conclusions

The hydrothermal synthesis of BaZr1-xYxO3-δ was carried out in supercritical water (410 °C/30.0 MPa) using a continuous flow reactor. This process allows the elaboration of nanoparticles of about 50 nm in diameter with great productivity (5.5 -6.8 g h -1 ), an average chemical reaction yield of 66.5 % and high reproducibility. XRD characterization revealed the presence of BaCO3 and few YO(OH) impurities. It is assumed that BaCO3 formation occurs due to faster kinetics compared to that of BZY formation. EDX study showed the obtaining of highly Ba-deficient perovskite and a substitution rate of Zr by Y of about 14%. However, a thermal treatment at 1000 °C for 1 hour

Figure 2

 2 Figure 2 shows the volume and number PSD of the synthesized powder. The volume PSD (Figure 1.a) exhibit a quadrimodal distribution with mean sizes at around 0.1 µm, 1.7 µm, 14 µm and 210 µm. The obtained D10, D50 and D90 are 0.817 µm, 4.570 µm and 35.73 µm respectively

  As a comparison, Sun et al. obtained a lattice parameter of 4.2048 Å for BaZr0.8Y0.2O3-δ prepared by combustion method, Nuñez et al. obtained a lattice parameter of 4.2067 Å for BaZr0.8Y0.2O3-δ prepared by a modified Pechini method and Sazinas et al. obtained a lattice parameter of 4.2151 Å for BaZr0.8Y0.2O3-δ prepared by spray pyrolysis and sintered at 1600 °C [31-33]. In order to investigate the origin of lattice parameter deviation, a comparison with undoped BaZrO3 elaborated by the same method was carried out. The refined lattice parameter is 4.1939 Å, this value agrees well with the 4.1930 Å and the 4.1943 Å obtained by the Nuñez group and the Akbarzadeh group

Figure 1 .Figure 2 .Figure 3 .Figure 4 .Figure 5 .

 12345 Figure 1. Schematic of the continuous hydrothermal set-up (adapted from[44]) (Not colored for the print version)

Acknowledgments:

The authors thank the ESIREM Engineering college for the SEM experimentations.

Funding: This research was funded in part by the Regional Council of Bourgogne Franche-Comté, the FEDER and the Graduate School EIPHI (Contract ANR-17-EURE-0002).

allowed the homogenization of the composition resulting in a Ba1.01Zr0.85Y0.15O3-δ perovskite phase.

In summary, this continuous hydrothermal synthesis in supercritical conditions is highly promising and extensive research on controlling the synthesis parameters would greatly broaden the possibilities for elaborating advanced ceramic materials at low temperature.

Conflicts of Interest:

The authors declare no conflict of interest.


S Perez

F-A Dauchy

F Salvo

M Quéroué

H Durox

P Delobel

R Chambault

M Ade

C Cazanave

A Desclaux

T Fabre

Hervé Dutronc
email: herve.dutronc@chu-bordeaux.fr

SEVERE ADVERSE EVENTS DURING MEDICAL AND SURGICAL TREATMENT OF HIP AND KNEE PROSTHETIC JOINT INFECTIONS

Keywords: adverse event, infection, prosthetic joint, risk factors

Introduction: The management of prosthetic joint infection requires a complex treatment procedure and can be associated with complications. However, the occurrence of severe adverse events during this intervention has been poorly evaluated.

Patients and methods: A 5-year multicentric retrospective study including patients from 3 hospitals in the South-Western France referral center for complex bone and joint infections (Crioac GSO) and treated for hip or knee prosthetic joint infection with 1 or 2-stage implant exchanges. The objective was to describe grade ≥ 3 adverse events, according to the CTCAE classification, occurring within 6 weeks after surgery and to identify their associated factors.

Results: 118 patients were identified. We observed 71 severe events in 50 patients (42.3 %; 95% confidence interval [CI95%]: 33.8-51.4%). Sixteen severe events were an evolution of the infection. The remaining 55 others (47 grade 3 and 8 grade 4) occurred in 41 patients (34.7%; CI95%: 26.8-43.7%). They were distributed as follows: 27 (49.1%) medical complications, 21 (38.2%) surgical complications and 7 (12.7%) antibiotic-related complications. The main identified risk factor was a two-stage prosthetic exchange with OR=3.6 (CI95% [1.11-11.94], p=0.032). Obesity was limit of significance with OR=3.3 (CI95 % [0.9-12.51], p=0.071). Infection with coagulase negative Staphylococcus was a protective factor with OR=0.3 (CI95% [0.12-0.99], p=0.047).

Conclusion:

Severe adverse events are frequent following prosthetic exchange for PJI (34.7%) and are related to the high frequency of comorbidities in this population and to the complex surgical procedures required. The risk factor significantly associated with these events was a two-stage exchange.

Introduction:

Prosthetic joint infection (PJI) is an infrequent orthopedic surgery complication which could have serious consequences, especially in terms of morbimortality and cost (1 -5). Treatment is complex, usually including surgery followed by antibiotherapy associating 1 or several molecules (6 -8). SAEs are sometimes due to this medical care which has been under evaluated. A recent study reports an SAE frequency of 15% during Staphylococcus aureus osteoarticular infection (OAI) treatment, although it focused exclusively on antibiotherapy related SAEs [START_REF] Valour | Antimicrobial-Related Severe Adverse Events during Treatment of Bone and Joint Infection Due to Methicillin-Susceptible Staphylococcus aureus[END_REF]. Better knowledge of SAEs and their causes could help diminish their frequency. This could lead to more optimal patient care and economic benefits. Our study's objective is to describe SAE frequency whatever their etiology during hip and knee PJI treatment appearing within 6 weeks after surgery, with a one or two stage implant exchange schedule as well as identifying associated risk factors.

Patients and methods: Study population:

We undertook a retrospective and descriptive study in the infectious diseases services of 3 teaching hospitals making up the South Western France referral center for complex bone and joint infections (Crioac GSO): the Bordeaux teaching hospital, which was the central coordinator, the Limoges teaching hospital and the Toulouse teaching hospital. The complex osteoarticular infractions referral center network is a national network existing in each French inter-region and certified by the Health Care General Direction (DGOS, Ministry of Social Affairs and Health). We were able to identify adult patients who had been admitted for a hip or knee PJI between January 1, 2013 and December 31, 2017 using the local Crioac data base (a computerized national data base, General Direction of Medical Care-DGOS). This data was then extracted from a computerized medical file. No information identifying the patients was collected in order to protect patients' privacy and anonymity. Patients suffering from a hip or knee PJI who had been operated on by a multidisciplinary team with a 1 or 2 stage implant exchange with regular ambulatory standardized follow-up were included in the study. We were able to identify all adverse effects (AEs) which appeared within a delay of 6 weeks after surgery. These AEs were then classified according to their degree of severity using the v.5 CTCAE (Common Terminology Criteria for Adverse Effects) classification [START_REF]Common Terminology Criteria for Adverse Events[END_REF]. The AEs were classified in 5 levels: AE level determination was accomplished by two independent readings by a clinician and a clinical study technician; unresolved disagreements were decided in meetings. SAEs were defined by levels 3 to 5.

Statistical analysis

Statistical analysis was performed using the R-studio software. A Wald test and a likelihood ratio test (LR-test) were carried out at the same time to obtain the associated p-value. After a descriptive analysis of the study population, the characteristics of patients with at least one SAE were compared to those of patients who experienced either AEs or non-serious AEs (levels 1 and 2). Univariate analysis and a multivariate analysis using a logistic regression were carried out in order to identify risk factors associated with SAE onset. For each variable, odds ratios were calculated with a confidence interval of 95%. The association was considered significant when the p-value was ≤ 0.05.

Results

:

Population description: Two hundred sixty-six patients were identified between January 1 2013 and December 31 2017. One hundred forty eight patients were excluded because they had not been treated completely in one of the 3 Crioac GSO teaching hospitals (CHU). The study therefore involved 118 patients. These patients' characteristics and their microbial ecology can be found in Table I. Of these patients, 50 developed an SAE (Table II).

Immediate post-operative antibiotherapy was probabilistic for 40 patients. This was comprised of piperacillin/tazobactam and vancomycin for 28 patients, of piperacillin/tazobactam and linezolid for 10 patients, of piperacillin/tazobactam and daptomycin for 1 patient and ceftriaxone and vancomycin for 1 patient. Average treatment duration was 7.8 days. For 73 patients, immediate postoperatory antibiotherapy was targeted using known pre-operatory patent information. For 5 patients, information concerning this probabilistic antibiotherapy was not recommended in their file. No SAE linked to this probabilistic antibiotherapy was noted.

The antibiotherapy was adapted upon receiving microbiological results. For the 26 cases of methicillin sensitive Staphylococcus aureus infection, it associated a penicillin M or a 1 st generation cephalosporin with a fluoroquinolone. Secondarily, β-lactam was replaced by rifampicin or clindamycin or fusidic acid or cefuroxime. For the 5 methicillin resistant Staphylococcus aureus infection cases, initial antibiotherapy associated vancomycin or daptomycin and cotrimoxazole then clindamycin and co-trimoxazole. For the 22 cases of methicillin sensitive coagulase negative Staphylococcus infection, antibiotherapy associated a penicillin M or a 1 st generation cephalosporin with a fluoroquinolone. Secondarily, the β-lactam was replaced by rifampicin or clindamycin. Other schemas associated co-trimoxazole and rifampicin or linezolid and fusidic acid. For the 8 cases of methicillin resistant coagulase negative Staphylococcus infection, antibiotherapy associated daptomycine and rifampicine or fusidic acid or ceftaroline. An others schemas associated cotrimoxazole and rifampicine or linézolide and fusidic acid. The 14 patients infected with enterobacteriaceae received monotherapy of fluoroquinolone or associated with co-trimoxazole or ceftriaxone. In other situations, co-trimoxazole was prescribed in monotherapy or, for β-lactamase secreting enterobacteriaceae, piperacillin/tazobactam or temocillin or aztreonam. Average documented overall antibiotherapy length was 7 weeks. Antifungal treatment length for the 2 patients was 12 and 28 weeks respectively.

Description of adverse events:

Out of the 118 patients included in the study, 191 all-level AEs were identified among 84 patients (71.1% of the studied group, with a confidence interval of 95% [CI 95%]: 62.4-78.6%). The average delay of AE appearance was 2 weeks following surgery (extremes: 0-42 days).

Among these events we were able to observe 71 SAEs in 50 patients (42.3%; CI 95% [33. 8-51.4]). The 68 other patients experienced no AEs or only level 1 and 2 AE. Among the 71 SAEs, 16 in 16 patients (13.5%; CI 95% [8.5-20.9]) corresponded to infection evolutivity. The other 55 SAEs concerned 41 patients (34.7%; CI 95% [26.8-43.7]) 7 of which also experienced SAEs linked to infection evolutivity. Among the 41 patients for whom SAE was not in relation with PJI evolution, 32 experienced only 1 SAE and 9 experienced several: 6 patients experienced 2 SAEs, 2 experienced 3 SAEs and 1 experienced 4 SAEs. There were 47 level 3 SAEs (85%) and 8 level 4 SAEs (15%). The 16 SAEs linked to PJI evolutivity (10 cases of surgery site infections and 6 cases of sepsis directly related to PJI) were excluded from the analysis. The remaining 55 SAEs can be found in Table II.

SAE associated determinants:

The comparative group was made up of 68 patients (57.6%): 36 had no AEs and 32 had 1 or several level 1 and 2 AEs. The significantly SAE associated variable was two-stage surgery with an odds ratio of 3.65 (CI 95% [1.11-11.94], p = 0.032). Obesity (body mass index [BMI] > 30), is close to significant with an odds ratio of 3.36 (CI 95% [0.9-12.51], p = 0.071).

Finally, coagulase negative Staphylococcus seems to be an SAE protecting factor with an odds ratio of 0.35 (CI 95% [o.12-0.99]; p = 0.047). Multivariate statistical analysis of all risk factors is presented in Table III.

Discussion:

We have noted that SAEs are frequent during prosthesis replacement, with an incidence of 34.7% in the 6 weeks following surgery. Our study describes all SAEs during medical-surgical prosthesis infection treatment, which has not been deeply investigated in the literature. A very recent study compared oral and intraveinal antibiotherapy for all types of OAIs, with or without material, treatment which was medical and at times surgical. Some authors also described SAEs which occurred within 6 weeks of the start of treatment. SAE incidence in these cases was 34.5% which concords with the frequency observed in our study [START_REF] Li | Oral versus Intravenous Antibiotics for Bone and Joint Infection[END_REF]. SAE types share certain characteristics. Most SAEs linked to medical care were due to patient comorbidity (49%), since their preexisting pathologies were decompensated by the complex OAI treatment. Elderly patients operated upon showed a greater number of comorbidities as compared to the rest of the population. Also, the literature records that medical-surgical treatment of prosthesis infections is more dangerous for patients 80 years of age and over, with significantly higher rates of mortality [START_REF] Jamakorzyan | Curative treatment of prosthetic joint infection in patients younger than 80 vs. 80 or older[END_REF]. This was not found in our study with a lack of significance concerning age. Among other medical SAEs, only 3 were linked to vein catheters (infection, thrombosis). This should, however, not lead to unnecessarily prolonged parenteral treatment.

SAEs linked to surgical treatment can be placed into 2 categories: hemorrhagic and orthopedic complications. Most were due to postoperative bleeding (81% of surgical SAEs). 30% of concerned patients were taking long-term curative anticoagulants, raising the problem of treatment management during perioperative periods and notably their possibly too precocious post-operative intake. There is, however, no real consensus regarding restarting anticoagulant treatment. As concerns surgery carrying a high degree of hemorrhagic risk, according to the French Anesthetist-Reanimation Society, direct oral intake of curative anticoagulants must begin within 24 to 72 hours. A venous anti-thrombotic prophylaxis must begin within 6 hours of surgery. As soon as hemostasis allows, curative anticoagulation (if recommended) by subcutaneous heparin injection should take place between 24 and 72 hours, replaced as soon as possible by antivitamin K and a halt to heparin as soon as the INR indicates a therapeutic state [START_REF] Albaladejo | Gestion des anticoagulants oraux directs pour la chirurgie et les actes invasifs programmés : propositions réactualisées du Groupe d'intérêt en hémostase périopératoire (GIHP) -septembre 2015[END_REF]. However, our study did not indicate a significantly higher number of hemorrhagic SAEs for the group taking long term anticoagulants. These post-operative hemorrhagic events represent 31.5% of all SAEs, making it possible to question anticoagulant prescriptions given the proportion of post-operative hematomas with, in certain cases, a need to re-operate. On the other hand, we have noted no thromboembolic complications. This leads us to hypothesize that the prescription of a preventive anticoagulant during the postoperative period for patients usually requiring a curative anticoagulant is sufficient (with the exception of patients having a mechanic cardiac valve).

Orthopedic SAEs, (non-hemorrhagic), make up 19% of the surgical SAEs. This can be explained by the fact that our center is a network of referral centers, so operated patients often have complex JPIs for which surgical intervention is difficult. Our study found no significant SAE difference between knee and hip exchanges.

Antibiotherapy linked SAEs occur at a rate close to that found in the study conducted by Valour et al. (12.7% vs 15%) [START_REF] Valour | Antimicrobial-Related Severe Adverse Events during Treatment of Bone and Joint Infection Due to Methicillin-Susceptible Staphylococcus aureus[END_REF], and are therefore not predominant in the proportion of SAEs. These medically adverse events are expected and known and have already been described in the literature: cytopenia, notably anemia under linezolid [START_REF] Hanai | A retrospective study of the risk factors for linezolid-induced thrombocytopenia and anemia[END_REF], rhabdomyolysis under daptomycin [START_REF] King | Daptomycin-induced rhabdomyolysis and acute liver injury[END_REF], cytolysis under rifampicin [START_REF] Devarbhavi | An Update on Drug-induced Liver Injury[END_REF], pancreatitis under cotrimoxazole [START_REF] Park | A case of recurrent pancreatitis induced by trimethoprimsulfamethoxazole re-exposure[END_REF]. These SAEs are sometimes due to strong doses prescribed during JPIs as is the case for amoxicillin with the appearance of acute kidney injury by crystalluria [START_REF]Rappel du bon usage de l'amoxicilline injectable pour diminuer le risque de cristalluries[END_REF].

We have identified a significantly associated factor in the appearance of SAEs: two-stage surgery and a significance lending factor: obesity. This is a known PJI risk factor aggravated even further with an elevated BMI [START_REF] Kunutsor | Patient-Related Risk Factors for Periprosthetic Joint Infection after Total Joint Arthroplasty: A Systematic Review and Meta-Analysis[END_REF]. Obesity is a growing public health problem and a factor in osteoarthritis, leading to prosthesis surgery, especially of the knee. It is also known that obesity aggravates the risk of surgical and anesthetic complications, increasing SAE frequency [START_REF] Gurunathan | Body mass index and in-hospital postoperative complications following primary total hip arthroplasty[END_REF]. In certain situations, however, prosthesis infection is a therapeutic emergency which does not give the patient enough time to lose weight before surgery. Patients suffering from obesity must take preventive measures before receiving their prosthesis. This parameter, in function of their BMI, presently represents a relative (BMI of between 30 and 40 kg/m 2 ) or absolute (BMI > 40 kg/m 2 ) prosthesis contraindication [START_REF] Feng | What modifiable and non-modifiable host factors contribute to an increased risk[END_REF].

The significance factor associated with SAE appearance in our study was 2-stage prosthesis exchange. Among the 50 patients suffering from SAEs, 45 (90%) underwent a 2-stage exchange and 5 (10%) underwent a 1-stage exchange. Predisposing factors are often a contraindication to 1-stage surgery according to certain authors: bad cutaneous state in view of the prosthesis, altered bone structure, complex microbiological results (unknown microorganism, high rate of resistance…) [START_REF] Lichstein | One-stage versus two-stage exchange[END_REF]. This explains the larger number of 2-stage surgeries in our study. Even if the success rate of 2-stage exchange is nearly 90% [START_REF] Lu | Infection after total knee arthroplasty and its gold standard surgical treatment: Spacers used in two-stage revision arthroplasty[END_REF], this surgery presents higher SAE risks since it concerns weaker and thus at-greater-risk patients. Since the choice of proceeding with 2-stage prosthesis exchange surgery is also influenced by difficult surgical conditions (acetabulum reconstruction, for example), the higher number of orthopedic SAEs is understandable. This has been verified in our study with an OR of 4.27% for this type of operation as opposed to a 1-stage surgery. In the measure where a recent meta-analysis demonstrated that the failure rate of 1-stage exchanges is quite similar to 2-stage exchanges [START_REF] Rowan | The Role of One-Stage Exchange for Prosthetic Joint Infection[END_REF], this treatment, which is a lesser source of SAEs, should be privileged for patients whose predisposition and classic PJI clinical presentation allow it.

Finally, coagulase negative Staphylococcus bacteriological evidence seems to be a protecting factor with regards to SAEs. Patients having PJI with this type of bacteria are younger, with less comorbidity. They received fewer anticoagulants and more often underwent 1-stage surgery.

As concerns the SAE rate in our study, the fact that patients were treated in 'last resort' referral centers should be taken into account. The same study undertaken in 'primary care' centers would thus probably not give the same results. The SAEs in this study are not negligible and should incite different practitioners (infectious disease specialists, orthopedic surgeons, and anesthetists) to analyze their patients' files very closely. The case of a patient who had already undergone several sepsis-complicated orthopedic operations or with SAE risk factors should thus be carefully analyzed and new surgery may end up being contraindicated.

Patient evaluation in the pre-operatory stage is essential and must best assess the operation's risk-benefit ratio. A scale of operatory scores would be an interesting concept as it can then establish, in the preoperational stage, the patient's status given his comorbidity and the clinical data concerning prosthesis infection and thus predict the outcome of surgery. This will allow for an appreciation of the riskbenefit ratio, so as to better define the most adapted treatment while diminishing the appearance of the SAEs which have such a devastating impact on these already-fragile patients.

The subject of this study has not been dealt with extensively in the literature. None have attempted to identify SAE associated factors, and only one recent publication described medical-surgical SAEs for all BJIs [START_REF] Li | Oral versus Intravenous Antibiotics for Bone and Joint Infection[END_REF]. A multicentric prospective cohort study would therefore be interesting to undertake in order to obtain a clearer image of SAEs and their determinants on the national scale. Finally, among the SAEs in this study, we have not included the 16 patients for whom their SAEs were linked to their BJI's evolution, since this was considered as 'uncontrollable' by medical-surgical treatment. If these treatment failures fill the definition of an SAE, they cannot be analyzed in the same way as the SAEs described in this work.

Conclusion:

SAE appearance is frequent during the 6 weeks following medicalsurgical treatment for knee or hip prosthesis infection, with implant exchange in either 1 or 2-stage operations. Medical SAEs are mostly linked to patient predisposition and comorbidity. The appearance of hemorrhagic accidents is the main surgical complication. The SAE associated factor is a 2-stage exchange operation and, to a lesser degree, obesity. This should encourage practitioners to offer, whenever possible, a 1-stage exchange operation. Obesity should be treated and prevented upstream, since this represents an infection risk and is significantly associated, according to our study, to SAE appearance. Precise pre-operatory patient evaluation is therefore necessary. A multicentric prospective cohort study could be undertaken in order to obtain a clearer evaluation of SAEs and their determinants. Also, starting from the latest and present data in the literature, a study attempting to establish an operability score with the possible appearance of an SAE as a main criterion would be helpful, since the use of such a tool in complex situations would constitute a decision-making aid.

Level 1 :

 1 light, asymptomatic or with light symptoms, classical clinical diagnosis only, not requiring treatment. Level 2: moderate, requiring minimal local or non-invasive treatment, interfering with instrumental activites of daily living. Level 3: severe or medically significant, but without a vital prognostic or need of hospitalization or prolongation of hospitalization, invalidating, interfering with basic activities of daily living. Level 4: with a vital prognostic, requiring urgent medical care. Level 5: AE related death.

Table I :

 I Description of the patient population (n=118)

	Tobacco	10	4 (4)	6 (12)	0,247
	Variables Cardio-vascular	Total 47	SAE 24 (35)	SAE 23 (46)	p-0,242
	disease	n = 118	negative	positive	value
	Obesity (BMI > 30)	16	n = 68 (%) 6 (6)	n = 50 10 (20)	0,087
	Immunodeficiency /	42	22 (32)	(%) 20 (40)	0,785
	Gender Others*
	Female Previous neoplasm	52 21	32 (47,1) 11 (16)	20 (40) 10 (20)	0,446 0,592
	Age Bacteriae
	50-59 S. aureus	14 31	10 (14,7) 17 (23)	4 (8) 14 (30)	0,688 0,71
	60-69 NCS**	27 30	13 (19,1) 22 (32)	14 (28) 8 (16)	0,047
	70-79	41 14	24 (35,3) 5 (7)	17 (34) 9 (18)	0,09
	≥ 80 Enterobacteriaceae	33 30	20 (29,4) 17 (25)	13 (26) 13 (26)	0,90
	Operating stages Other microorganisms***	13	7 (10)	6 (12)	0,77
	1 stage Negative	23	18 (26)	5 (10)	0,031
	2 stages Culture	95	50 (73)	45 (90)
	Prosthesis type
	Hip *Others: chronic kidney failure, diabetes 73 40 (59)	33 (66)	0,428
	Knee (exchange ** NCS: coagulase negative Staphylococcus 45 28 (41)	17 (34)
	and single *** Other microorganisms: streptococcus (n=8), enterococcus (n=6),
	compartment ) Gram positive bacillus (n=14), Candida (n=2)
	Anticoagulants	28	17 (25)	11 (22)	0,705

Table II :

 II Description of severe adverse events (n=55)

	Types of adverse events	Number
	Medical
	Cardio-pulmonary complications
	Atrial fibrillation	2
	Myocardial heart failure	1
	Cardiac decompensation	2
	Respiratory distress	3
	Hypotension	1
	Infectious complications unlinked to
	SAE
	infection of catheter	3
	urinary infection	4
	aspiration pneumonia	1
	Neurological Complications
	epilepsy	2
	acute confusion	1
	Un-medicated Acute kidney injury	3
	Hyponatremia, hypokalemia,
	neutropenia

Table III :

 III Determinants associated with severe adverse events in multivariate analysis (n=118 patients)

	Variables	OR	IC 95% p-value
	2-stage exchange	3,65	1,11 -11,94	0,032
	Obesity	3,36	0,9 -	0,071
			12,51
	Coagulase negative	0,35	0,12 -	0,047
	Staphylococcus		0,99

Acknowledgments:

The authors would like to thank Pauline Perreau for her technical help in data collection.


Julien Soulat

Valérie Monteils

Marie-Pierre Ellies-Oury

S Papillon

Brigitte Picard
email: brigitte.picard@inrae.fr

M.-P Ellies-Oury

What is the impact of the rearing management applied during the heifers' whole life on the toughness of five raw rib muscles in relation with carcass traits?

Keywords: Raw meat, Shear force, Rearing factors, Prediction models

However, when the consumers purchase and eat ribs or short ribs, several muscles with different properties and levels of quality compose the wholesale cuts. Consequently, in the present study we considered the main five muscles constituting the rib from the chuck sale section. As the cooking conditions could be different according to countries or the consumer tastes (rare, medium-rare or well-cooked) and had an impact on the final tenderness of meat [START_REF] Gagaoua | Inter-laboratory assessment by trained panelists from France and the United Kingdom of beef cooked at two different end-point temperatures[END_REF], we chose to evaluate the toughness of aged meat on raw muscles to be in conditions as close as possible to those of the consumer when he buys the meat.

Moreover, we considered the rearing management applied during the heifers' whole life and not only during the fattening period as in [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF]. So, the first aim of this work was to analyse the effect of rearing managements, carcass quality, and their interaction on the toughness measured by Warner-Bratzler shear force, of five raw rib muscles: M. complexus (CP), M. infraspinatus (IF), LM, M. rhomboideus (RH), and M. serratus ventralis (SV). The second aim was to identify rearing factors and/or carcass traits that could be used to manage simultaneously the toughness of these five raw muscles.

Material and methods

Animals, rearing managements, slaughtering and carcass traits

This study used 77 crossed Charolais x Aubrac heifers from eight commercial farms.

Surveys were performed to collect 46 rearing factors (Tables 1 to 3) characterizing three key periods of the whole heifers' life (from birth to slaughter): pre-weaning (PWP), growth period (GP) and fattening period (FP) (Soulat et al., 2018a). Then, the four rearing managements (RM) described by [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF] were used in this study. The main characteristics of these RM are summarized in the Fig. 1.

The 77 heifers were slaughtered in the same industrial slaughterhouse (Abattoir du Gévaudan, Antrenas, France). Six carcass traits were collected: cold carcass weight (calculated from the measured hot carcass weight x 0.98, kg), dressing percentage (ratio of cold carcass weight to live weight before slaughter, %), conformation and fat scores using the EUROP system [START_REF] Ec | Council Regulation (EC) No 1183/2006 of 24 July 2006 concerning the Community scale for the classification of carcasses of adult bovine animals[END_REF] and the pH and the temperature at 24 h post-mortem (pH 24h and Temp 24h, respectively) (Table 4). In the EUROP system, the conformation score is divided into five ordered classes (E = very high; to P = very poor muscle development). Moreover, each class has three subdivisions (high: "+", average: "=", and low: "-"). The fat score is divided into five ordered classes (1 = lean; to 5 = very fat). All carcasses of this study had a fat score of 3, consequently this parameter was not considered.

The two carcass quality clusters (CARCA-Low and CARCA-High) described by [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF] were used in this study. The carcasses in CARCA-High had significantly higher cold weight, and dressing percentage than those in CARCA-Low. Moreover, the CARCA-High cluster was composed mainly by carcasses of the classes U+ and U=, whereas the CARCA-Low cluster was composed by carcasses of the classes U-and R+.

Muscle sampling and meat quality trait

Two beef ribs (the 5th and the 4th) of each carcass were collected, at 24 h post-mortem, as described in [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF]. Then, each beef rib sample (n = 77) was individually vacuum-packaged and aged for 14 days at 4 °C. After, these samples were frozen and stored at -20 °C until the analyses.

After thawing of the beef rib samples (around 48h), the shear force was measured on five muscles: CP, IF, LM, RH, and SV, using a Warner-Braztler apparatus (EZ-SX set assay EU RoHS, Shimadzu, Kyoto, Japan). For each beef rib samples, the five muscles were dissected and meat portions (length: 1.5 to 3 cm; width: 1 cm; and thickness: 0.5 to 1 cm) were cut. The shear force was measured cutting perpendicularly to the fibers of the raw meat portions (least five portions) obtained and calculated using the Trapezium X 1-5.1 software (Shimadzu, Kyoto, Japan) [START_REF] Wheeler | A comparison of Warner-Bratzler shear force assessment within and among institutions[END_REF].

For each muscle, the data of shear force are presented in the Table 4.

Statistical analyses

Statistical analyses were performed using R 4.0.0 software (R core Team, 2020). The statistical procedures performed in this work were summarized in the Fig. 2.

Descriptive statistical analyses

For the shear force, an ANOVA with random effects (mixed model) was performed to evaluate its dependence on the RM, the carcass quality cluster and the muscle. The fixed effects were: RM, carcass quality, muscle, RM x muscle interaction, and carcass quality x muscle interaction; and the random effect was: animal. If an interaction was not significant in the ANOVA, a new ANOVA was performed without this interaction in the model. Then, if the results of the mixed model were significant, a Tukey test was performed. The mixed model was performed using the "lmerTest" [START_REF] Kuznetsova | lmerTest Package: package: tests in linear mixed effects models[END_REF] package and the Tukey test was carried out using the "emmeans" [START_REF] Lenth | emmeans: Estimated Marginal Means, aka Least-Squares Means[END_REF] and "multcompView" [START_REF] Graves | multcompView: Visualizations of Paired Comparisons[END_REF]

A principal component analysis (PCA) was performed to illustrate the relationships between the shear force values of the 5 muscles, using the "FactoMineR" [START_REF] Le | FactoMineR: An R Package for Multivariate Analysis[END_REF] package.

Predictive statistical analyses

Before establishing the models of prediction, a first step was performed to test the multicollinearity between the 46 rearing factors (Fig. 2). The multicollinearity was tested using the variance inflation factors (VIF) calculated from the "car" package [START_REF] Fox | An R Companion to Applied Regression[END_REF]. As explained by Soulat et al. (2018a), the explicative variables with the greatest VIF were removed one by one, to finally obtain explicative variables with VIF < 10. After this step, 19 rearing factors were retained (these rearing factors are described in Tables 1 to 3,in bold): -Rearing factors for the pre-weaning period (p = 10):

• Birth weight This process was similarly performed on the carcass traits (p = 5) which all had VIF < 10.

Three linear models were developed to predict the shear force (SF) of the 5 muscles. The first one (RF_SF) was obtained from the selected rearing factors, the second one (CARCA_SF) from the carcass data, and the last one (RF&CARCA_SF) from the selected rearing factors and the carcass data (Fig. 2).

To obtain our final prediction models, the procedure described in Soulat et al. (2018a) was applied. For example, initially in the complete RF_SF model, all rearing factors selected and the muscle factor were included. Then, the non-significant rearing factors were removed one by one to obtain the simplest prediction model. After each withdrawal, using a probability ratio test, the new model was compared with the previous model. If the result of the comparison between 2 models was P < 0.10, the independent variable was conserved (Fig. 2).

As an external validation of the prediction models was not possible with the number of animals in our dataset, the validation of each model was performed using the bootstrap procedure (Tan et al., 2006). For each developed model, this procedure was repeated 500 times to generate 500 bootstrap samples. After the bootstrap procedure, the mean coefficient of each independent variable was calculated. The number of times the coefficients of the independent variables in the model were significant was counted over the 500 repetitions.

To evaluate the quality of the prediction models, three criteria were considered to describe the robustness of the model from the root mean square errors of prediction (RMSEP, [START_REF] Kobayashi | Comparing simulated and measured values using mean squared deviation and its components[END_REF]), the accuracy of the model from the mean prediction error (MPE, [START_REF] Yan | Prediction of nitrogen excretion in feces and urine of beef cattle offered diets containing grass silage[END_REF]), and the precision of the model from the coefficient of determination (R²). In this study, the RMSEP, MPE, and R² were calculated at each repetition of the bootstrap. Then, the mean of these three criteria was calculated. As in [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF], the developed models were considered to have a high or good accuracy when MPE ranged from 0.10 to 0.30 and to have a high precision when R² was the closest to 1. To compare the different prediction models, the Akaike information criterion (AIC) was also calculated. The best model has the lowest calculated AIC, RMSEP, and MPE values and the highest R² value.

Results and discussion

Effects of the rearing managements, muscle, and carcass quality clusters on the toughness of raw aged meat

According to our results, the interaction between the rearing management and muscle, and the carcass clusters had a significant effect on the toughness of the raw meat (Table 5). The toughness of the CP, LM, RH, and SV muscles was not significantly different when the heifers received the same rearing management (Fig. 3). In cattle, the RH and SV muscles are postural muscles, the LM is a support muscle, and the CP muscle is involved in the movement of the animal's head [START_REF] Totland | Distribution patterns of muscle-fiber types in major muscles of the bull (bos-taurus)[END_REF]; University of Nebraska-Lincoln, 2020). The muscle fiber characteristics could be impacted by the muscle type (S. T. [START_REF] Joo | Control of fresh meat quality through manipulation of muscle fiber characteristics[END_REF]Picard & Gagaoua, 2020;[START_REF] Totland | Distribution patterns of muscle-fiber types in major muscles of the bull (bos-taurus)[END_REF]. However, the location and the function of these 5 muscles did not seem to have an impact on their toughness. The toughness of IF muscle, which is also a postural muscle, was the highest among the 5 muscles and the most sensitive to changes in rearing managements. More precisely, the IF muscle was tougher for heifers from RM-4 than for those from RM-2 and RM-3 (Fig. 3). According to the traits of the 4 rearing managements described in [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF] and used in this work, the main differences between RM-4 and both rearing managements 2 and 3 were:

-During PWP, the calves from RM-4 had higher average daily gain and pasture duration than those from RM-2 and RM-3 -During GP, the heifers from RM-4 had lower number of days of offered concentrates in the diet and lower pasture duration than those from RM-2 and RM-3. The average concentrate's crude protein and net energy contents (calculated across the whole growth period) were lower in RM-4 than in RM-2 and RM-3.

-During FP, the fattening of heifers from RM-4 was performed at pasture. In this rearing management, the heifers were older at the beginning of their fattening than those from RM-2 and RM-3. The heifers from RM-4 had lower concentrate intake during this period than those from RM-2 and RM-3. The average forage's crude protein and neutral detergent fiber contents (calculated across the whole fattening period) were lower in RM-4 than in RM-2 and RM-3.

In the literature, there are few works which studied the effects of several rearing factors on the toughness of raw meat. Moreover, there are also few works which studied the effects of rearing factors applied before the fattening period on the meat tenderness. These results were obtained on cooked meat making it difficult to compare to ours results. [START_REF] Hennessy | Improving the pre-weaning nutrition of calves by supplementation of the cow and/or the calf while grazing low quality pastures -2. Calf growth, carcass yield and eating quality[END_REF] observed that the tenderness of LM was lower when calves had a quick growth before weaning. In our study, the calves from the RM-4 had a quicker growth before weaning than those from RM-2 and RM-3. However, the toughness of raw LM was similar for these 3 rearing managements (Fig. 3). In our study, the animals were slaughtered older than those in [START_REF] Hennessy | Improving the pre-weaning nutrition of calves by supplementation of the cow and/or the calf while grazing low quality pastures -2. Calf growth, carcass yield and eating quality[END_REF]. No significant differences were observed between these 3 rearing managements for the other muscles except for the raw IF muscle. It was possible that the slaughter age mitigated the effect of the growth rate before weaning, except on the toughness of IF. [START_REF] Modzelewska-Kapitula | The influence of diet on collagen content and quality attributes of infraspinatus muscle from Holstein-Friesian young bulls[END_REF] showed that the proportion of fat in the raw IF muscle was significantly higher when the young bulls had a quick growth during their fattening. The growth speed of animal could had an impact more or less important according to the muscle.

During the growth period, [START_REF] Miller | The influence of diet and time on feed on carcass traits and quality[END_REF] did not observe an effect of the diet's energetic level on the tenderness of LM, M. semimembranosus, and M. semitendinosus cooked meat. It could be possible that the IF muscle was more sensitive to this factor than these three muscles.

During the fattening period, the heifers consumed variable concentrate quantities according to the rearing management. However, many studies did not observe an effect of the concentrate quantity in the fattening diet on the tenderness of LM after cooking [START_REF] French | The eating duality of meat of steers fed grass and/or concentrates[END_REF][START_REF] Keady | Effects of replacing grass silage with maize silages differing in inclusion level and maturity on the performance, meat quality and concentrate-sparing effect of beef cattle[END_REF][START_REF] Moloney | Characteristics of fat and muscle from beef heifers offered a grass silage or concentrate-based finishing ration[END_REF]. Moreover, during their life, the heifers from the RM-4 had the longest pasture duration, consequently these heifers had a higher physical activity than those in housing. According to the results of [START_REF] Cozzi | Comparison of two feeding finishing treatments on production and quality of organic beef[END_REF], the LM after cooking was tougher when heifers performed their fattening at pasture. This result could partly explain why the raw IF muscle is tougher for heifers from the RM-4. The physical activity could have an effect on the connective tissue and/or the myofibril integrity of this muscle. The results of [START_REF] Modzelewska-Kapitula | The influence of diet on collagen content and quality attributes of infraspinatus muscle from Holstein-Friesian young bulls[END_REF] showed that the fattening diet had not a significant effect on the tenderness of IF muscle after cooking, in young bulls fattening in a free-stall. However, for the LM, [START_REF] Pordomingo | Effect of feeding treatment during the backgrounding phase of beef production from pasture on: I. Animal performance, carcass and meat quality[END_REF] did not observe an effect of the fattening type (pasture vs. housing) on the meat tenderness, in heifers.

In accordance with previous results, the difference of IF toughness observed between the rearing managements could not be explained by one rearing factor [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF]2018b). Moreover, the raw IF muscle was also tougher than the four other muscles regardless of the rearing management (Fig. 3). After 24h post-mortem, Torrescano et al. (2003) observed also that the raw IF muscle was tougher than the raw LM. The IF muscle is an oxidative muscle and contained a higher proportion of type I fibers (79%) and a lower proportion of type IIA and IIX fibers than LM, SV, and RH [START_REF] Totland | Distribution patterns of muscle-fiber types in major muscles of the bull (bos-taurus)[END_REF]. The IF muscle is one of the major postural muscles in the forepart with mean size of type I above 4000 µm² and IIX between 2000 and 2500 µm², respectively [START_REF] Totland | Distribution patterns of muscle-fiber types in major muscles of the bull (bos-taurus)[END_REF]. The mean size of type I fibers of SV muscle was also above 4000 µm², whereas, the mean size of type IIX fibers was between 3000 and 3500 µm². For the LM, the size of type I and IIX fibres was below 3100 µm² and above 3800 µm² [START_REF] Jurie | Effects of age and breed of beef bulls on growth parameters, carcass and muscle characteristics[END_REF][START_REF] Jurie | Muscle and meat quality characteristics of Holstein and Salers cull cows[END_REF]. According to the results of Torrescano et al. (2003), the IF muscle had more insoluble collagen than the raw LM, without aging. After aging, the IF muscle had lower myofibrillar fragmentation index, higher sarcomere length, proportion of intramuscular fat, collagen level, and pH 48h than LM (Purchas & Zou, 2008;[START_REF] Veiseth-Kent | Can postmortem proteolysis explain tenderness differences in various bovine muscles[END_REF]. These different traits between the IF and the others rib's muscles could explain the difference of toughness observed for the raw meat.

The result of the PCA showed that the tenderness of IF muscle was less correlated with the tenderness of the other four muscles (Fig. 4). However, the shear force values of the 5 muscles were positively correlated.

Only for heifers from RM-2, the LM was more tender than CP and RH muscles, without cooking (Fig. 3). The main differences of the RM-2 with the 3 other were during the fattening period (Fig. 1). Briefly, the heifers from RM-2 were lighter and younger at the beginning of the fattening with a fattening outside without pasture. Moreover, the fattening duration was the longest and the quantity of concentrate intake was the highest. In accordance with our results, Thenard et al. (2006) observed also that the raw RH muscle was tougher than the LM.

According to these authors, the RH muscle had higher total collagen and lower proportion of soluble collagen than LM. The RH contained a higher proportion of type I fibers and a lower proportion of type IIA fibers than LM [START_REF] Totland | Distribution patterns of muscle-fiber types in major muscles of the bull (bos-taurus)[END_REF].The toughness difference observed between both muscles could be mainly explained by the muscle traits. To our knowledge, there are no works studying the toughness of raw CP. However, the RH was tougher than CP after cooking [START_REF] Bratcher | The effects of quality grade, aging, and location within muscle on Warner-Bratzler shear force in beef muscles of locomotion[END_REF].

The five raw muscles were the tougher for CARCA-Low cluster (Table 5). According to Soulat et al. ( 2020) and [START_REF] Gagaoua | Decision tree, a learning tool for the prediction of beef tenderness using rearing factors and carcass characteristics[END_REF], the carcass traits can be linked to a higher overall tenderness. The heavier carcasses with higher dressing percentage and conformation produced raw LM and M. rectus abdominis (RA) more tender, in heifers (Ellies- [START_REF] Ellies-Oury | Effect of age and carcass weight on quality traits of m. rectus abdominis from Charolais heifers[END_REF][START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF]. For cooked meat, [START_REF] Gagaoua | Decision tree, a learning tool for the prediction of beef tenderness using rearing factors and carcass characteristics[END_REF] observed that the LM had the highest tenderness when the carcasses had a fat score ≥ 2.42, a cold carcass weight < 419 kg, and a dressing percentage ≥ 60%. However, [START_REF] Couvreur | Relationships Between Cull Beef Cow Characteristics, Finishing Practices and Meat Quality Traits of Longissimus thoracis and Rectus abdominis[END_REF] did not observe difference on the tenderness of LM in cull cows between both clusters: Ylight (young and light cows) and Yheavy (young and heavy cows), after cooking. Moreover, after 14 days of aging, Ellies- [START_REF] Ellies-Oury | Effect of age and carcass weight on quality traits of m. rectus abdominis from Charolais heifers[END_REF] and [START_REF] Agbeniga | Influence of carcass weight on meat quality of commercial feedlot steers with similar feedlot, slaughter and post-mortem management[END_REF] did not observe an effect of cold carcass weight on the tenderness of RA and LM muscles, respectively.

Identification of rearing factors and carcass traits to reduce the toughness of the five raw aged rib's muscles

In this work, three models were proposed to predict the shear force of the five-aged rib's muscles. In the RF_SF and CARCA_ SF models, the shear force was only predicted from rearing factors or carcass traits, respectively. In the RF&CARCA_SF, the shear force was predicted from rearing factors and carcass traits. The parameters of prediction quality (AIC, R² and MPE) of these three models were similar (Table 6). However, these models explained only about 40% of the shear force's variability observed.

According to the coefficient of the independent variables in the 3 models, if one of these variables was increased, the raw meat was low tough.

In the RF_SF model, the independent variables considered were age of the cow, the ADG during GP and FP, and the slaughter age (Table 6).

To our knowledge, the effect of the age of the cow on the meat toughness has not been studied. It is possible that the physiological stage, the genetic and/or the epigenetic of the cow influence the meat toughness of this progeny. Contrary to our results, [START_REF] Hennessy | Improving the pre-weaning nutrition of calves by supplementation of the cow and/or the calf while grazing low quality pastures -2. Calf growth, carcass yield and eating quality[END_REF] observed a decreased of LM tenderness when the calves had high ADG before weaning. In our study, heifers were slaughtered older than cattle in [START_REF] Hennessy | Improving the pre-weaning nutrition of calves by supplementation of the cow and/or the calf while grazing low quality pastures -2. Calf growth, carcass yield and eating quality[END_REF]. Although the slaughter age was less often significant in the RF_SF model compared to the three others independent variables, this rearing factors had an impact on the toughness. In accordance with Soulat et al. (2018a) for the RA, the slaughter of older heifers allowed to have a tenderness meat higher. [START_REF] Ahnstrom | Influence of slaughter age and carcass suspension on meat quality in Angus heifers[END_REF] and [START_REF] Bures | Growth performance, carcass traits and meat quality of bulls and heifers slaughtered at different ages[END_REF] observed also an increase of the LM tenderness when the heifers were slaughtered older.

The raw meat from these five muscles is potentially less tough if the heifer's mother is an older cow, if the heifer has a quick growth during GP and FP, and/or if the heifer is slaughtered older.

In the CARCA_SF model, the independent variables considered in the model were the cold weight and Temp 24h of the carcass (Table 6). In accordance with our results, Ellies- [START_REF] Ellies-Oury | Effect of age and carcass weight on quality traits of m. rectus abdominis from Charolais heifers[END_REF] observed that the raw RA was more tender when the carcasses were heavier, in heifers. After cooking, these authors did not observe an effect of carcass weight on the tenderness of RA muscle. According to the results of [START_REF] Agbeniga | Influence of carcass weight on meat quality of commercial feedlot steers with similar feedlot, slaughter and post-mortem management[END_REF], the LM from heavy carcasses was also more tender than those from light carcasses after 3 days of aging and cooking. However, no effect of the carcass weight was observed on the LM tenderness after 14 days of aging, by these authors. Moreover, some studies observed that the LM was significantly more tender when the young bulls or steers were slaughter heavier (Keane & Allen, 1998;Sañudo et al., 2004). In our model CARCA_SF, Temp 24h of the carcass had an effect on the toughness of the raw meat. According to our results, the carcasses with a slow chilling produce a raw meat low tough. This result reinforces that the shear force of LM increased with a quick chilling of the carcass [START_REF] Mao | Effect of Rapid Chilling on Beef Quality and Cytoskeletal Protein Degradation in Mlongissimus of Chinese Yellow Crossbred Bulls[END_REF][START_REF] Zhang | Effect of carcass chilling on the palatability traits and safety of fresh red meat[END_REF].

Our results displayed that the heavier carcasses with a Temp 24h higher increased the potential to obtain raw meat low tough, independently of the rearing management.

When both rearing factors and carcass traits are considered simultaneously in the RF&CARCA_SF model, the independent variables included in the model were age of the cow and the cold weight and the temperature at 24h of the carcass (Table 6). In this model, we found independent variables considered in RF_SF and CARCA_SF. However, the simultaneous consideration of the rearing factors and the carcass traits did not allow to an improvement in the prediction quality of the five muscles' shear force.

For the same prediction quality of the shear force, the CARCA_SF model seems to be the simplest model to implement because its independent variables are easily recoverable at the slaughterhouse. However, the RM_SF appeared also interesting to manage the tenderness potential of raw meat early.

Conclusion

These results showed that the 4 rearing managements applied during the heifers' whole life did not significantly impact the toughness of the raw CP, LM, RH, and SV muscles. They displayed that the toughness of the raw IF muscle was higher and more sensitive to the rearing management than the other muscles. Moreover, the toughness of the five muscles was lower when the carcass was heavier and had higher dressing percentage and conformation score.

Our results displayed also some rearing factors (age of the cow, ADG during GP and FP, and slaughter age) and some carcass traits (cold carcass weight and Temp 24h) which could be used as lever to improve the potential tenderness of the 5 raw rib's muscles studied.

Consequently, these data highlighted that it could be possible to manage simultaneously the tenderness potential of different rib's muscles during the animals' life. This work can contribute to study the potential tenderness of meat to help the beef sector (from the farm to the plate of consumer) to improve the quality of meat products by adaptation of the rearing system.

In complement to this work, it would be interesting to study the effects of the rearing managements and carcass traits on the tenderness of cooked meat to precise the effect of cooking on the potential tenderness, and to analyse others muscles from the same carcass to evaluate the quality of many meat cuts. Purchas, R. W., & Zou, M. (2008). Composition and quality differences between the longissimus and infraspinatus muscles for several groups of pasture-finished cattle.

Meat Science, 80 [START_REF]DM = dry matter. 3 Forage = hay + grass silage + wrapped haylage[END_REF], 470-479. R core Team. (2020). R. A language and environment for statistical computing. R Foundation for Statistical Computing. http://www.R-project.org/. Accessed March 9, 2021 Soulat, J., Picard, B., & Monteils, V. (2020). Influence of the rearing managements and carcass traits on the sensory properties of two muscles: Longissimus thoracis and rectus abdominis. Meat Science, 108204. Soulat, J., Monteils, V., & Picard, B. (2019). Effect of the rearing managements applied during heifers' whole life on quality traits of five muscles of the beef rib. Foods, 8( 5 (2006). Grass steer production system to improve carcass and meat quality. Livestock Science, 105 (1-3), 185-197. Torrescano, G., Sánchez-Escalante, A., Giménez, B., Roncalés, P., & Beltrán, J. A. (2003).

Shear values of raw samples of 14 bovine muscles and their relation to muscle collagen characteristics. Meat Science, 64 [START_REF]SE = standard error[END_REF], 85-91. Across the whole GP, the calculated average percentage of hay in the housing diet was between 40% and 80% 19 > 80% Across the whole GP, the calculated average percentage of hay in the housing diet was above 80% 17 Grass_silage_GP (%) 0% Across the whole GP, the heifers had not grass silage in the housing diet 42 < 50%

List of figures

Across the whole GP, the calculated average percentage of grass silage in the housing diet was below 50% 8 > 50%

Across the whole GP, the calculated average percentage of grass silage in the housing diet was above 50% 27 Wrapped_haylage_GP (%) 0% Across the GP, the heifers had not wrapped haylage in the housing diet 41 < 40%

Across the GP, the calculated average percentage of wrapped haylage in the housing diet was below 40% 10 [40%; 60%] Across the GP, the calculated average percentage of wrapped haylage in the housing diet was between 40% and 60% 14 > 60% Across the GP, the calculated average percentage of wrapped haylage in the housing diet was above 60% 12 GP_duration (day) < 500 days The number of days between the weaning and the beginning of the fattening was below 500 days 16 > 500 days

The number of days between the weaning and the beginning of the fattening was above 500 days 61 Nature of pasture Grass During above 75% of the pasture period, the heifer diet was only grass 58

Grass & Hay During above 75% of the pasture period, the heifer diet was grass and a hay complement 19

1 SE = standard error.

2 DM = dry matter. 2 SE = standard error.

3 Rearing managements = the four rearing managements considered were defined and described in Soulat et al. (2020).

4 Carcass clusters = carcass clusters' traits were defined and described in [START_REF] Bonnet | Quantification of biomarkers for beef meat qualities using a combination of Parallel Reaction Monitoring-and antibody-based proteomics[END_REF].

•

  Total time spent by the calf with her mother between the birth and the weaning • Insemination type (artificial or natural) • Calving (intervention or not of the farmer during the calving) • Calculated average of the concentrates' crude protein in the diet during PWP • Average daily gain (ADG) of the calf between the birth and the weaning • Offered or not concentrates in housing calf diet during PWP -Rearing factors for the growth period (p = 2): • ADG between the weaning and the beginning of the fattening period • Nature of pasture (during the pasture, heifers diet was complemented by hay or not). -Rearing factors for the fattening period (p = 7): • Slaughter age • ADG between the beginning of FP and the slaughter • Calculation of the grass silage percentage in the average diet across the whole FP • Calculation of the wrapped haylage percentage in the average diet across the whole FP • Calculated average of the forage's crude protein content across the whole FP • Calculated average of the forage's net energy content across the whole FP • Calculated average of the concentrate's net energy content the whole FP

  .,Picard, B., Léger, S., & Monteils, V. (2018a). Prediction of beef carcass and meat quality traits from factors characterising the rearing management system applied during the whole life of heifers. Meat Science, 140, 88-100. Soulat, J., Picard, B., Léger, S., Ellies-Oury, M.-P., & Monteils, V. (2018b). Preliminary study to determinate the effect of the rearing managements applied during heifers' whole life on carcass and flank steak quality. Foods, 7(10), 160. Tan, P.-N., Steinbach, M., & Kumar, V. (2006). Introduction to Data Mining (1st ed.). Pearson International Edition. Thenard, V., Dumont, R., Grosse, M., Trommenschlager, J. M., Fiorelli, J. L., & Roux, M.

Fig. 1 .

 1 Fig. 1. Summary of the four rearing managements applied during the heifers' whole life

Fig. 2 .Fig. 3 .

 23 Fig. 2. Framework of the statistical procedures performed in this study: descriptive and

Fig. 4 .

 4 Fig. 4. Principal component analysis of shear force of the raw five rib's muscles (M.

•

  Age of the heifer's mother at the heifer's birth (age of the cow)

	• Age of the heifer's mother at first calving
	• Pre-weaning duration

Table 1

 1 Description of the rearing factors characterizing the pre-weaning period (PWP) (in bold, the rearing factors conserved after the test of multicollinearity).

	Pre-weaning period
	Quantitative rearing factors	Description of the rearing factor

2 DM = dry matter.

Table 2 554

 2 Description of the rearing factors characterizing the growth period (GP) (in bold, the rearing factors conserved after the test of multicollinearity).

	555
	Growth period
	Quantitative rearing factors	Description of the rearing factor

Table 3

 3 Description of the rearing factors characterizing the fattening period (FP) (in bold, the rearing factors conserved after the test of multicollinearity).

	Fattening period
	Quantitative rearing factors	Description of the rearing factor

Table 4

 4 Description of the carcass traits and the shear force of the five rib's muscles.

	Carcass traits
	Quantitative rearing factors Mean ± SE 1	Min	Max
	Cold weight (kg)	425 ± 4.79	330	509
	Dressing percentage (%)	58.5 ± 0.24	53.6	65.6
	Temperature at 24 h (°C)	6.8 ± 0.11	4.0	9.6
	Qualitative carcass traits	Modalities of the carcass traits	n
	Number of carcasses per EUROP class 2
		E-		3
		U+		24
		U=		28
		U-		16
		R+		6
	pH 24 h
		< 5.8		22
		≥ 5.8		55
	Meat traits
	Shear force (N/cm²)	Mean ± SE	Min	Max
	M. complexus	60.8 ± 1.75	27.9	110.3
	M. infraspinatus	90.7 ± 3.08	45.5	162.4
	M. longissimus	45.2 ± 1.43	23.7	88.5
	M. rhomboideus	61.1 ± 1.99	13.3	112.9
	M. serratus ventralis	54.1 ± 1.88	31.2	125.3
	1 SE = standard error.

2

The EUROP classes are E+ (extremely muscled), E=, E-, […], P+, P=, and P-(very poorly muscled).

Table 5

 5 Effects of the rearing managements, carcass clusters, muscle and their interaction on the toughness of the meat.

		Shear force (N/cm²)
		Emmean 1	SE 2
	Rearing management 3 (RM)
	RM-1	63.2	2.51
	RM-2	64.3	3.01
	RM-3	60.8	2.36
	RM-4	68.7	2.36
	Carcass clusters 4 (C)
	CARCA-Low	67.9	2.52
	CARCA-High	60.6	1.41
	Muscles (M)
	M. complexus	62.6	2.16
	M. infraspinatus	92.6	2.19
	M. longissimus	46.8	2.16
	M. rhomboideus	63.0	2.16
	M. serratus ventralis 56.2	2.17
	P-value
	RM	0.13
	C	0.01
	M	< 0.001
	M x RM	0.007

1 Emmean = estimated marginal means.

Acknowledgments

The authors thank the European protected geographical indication "Fleur d'Aubrac" for this implication in this study, in particular the farmers surveyed, the coordinators of this stock farming sector, and the slaughterhouse staff. The authors thank also INRAE institute staff particularly David Chadeyron for sampling at slaughter. The authors thank the support received from the French regional council of Occitanie (number 17011758) and the French government IDEX-ISITE initiative 16-IDEX-0001 .

Table 6

Equations and performances for the three linear prediction models of shear force (RF_SF model established from only rearing factors, CARCA_SF model established from only carcass traits, and RF&CARCA_SF model established from rearing factors and carcass traits).

Models

Independent variables 1 Coefficients (± SD) N of significant variables over 500 bootstraps Temperature at 24 h -2.0 ± 1.0 316

1 For the explanation of the models' independent variables please refer to the following tables: Tables 1 to 3 for the rearing factors, and Table 4 for the carcass traits.

2 Number of times the independent variables were significant in the model over 500 bootstraps.

3 RMSEP = root mean square error of prediction.

4 MPE = mean prediction error.

5 AIC = Akaike information criterion.

6 CI = confidence interval. Determination of the carcass quality clusters (using a factor analysis for mixed data following then a hierarchical clustering on principal components).

2

Performing of the ANOVA. 5 Establishment of the prediction model (using linear regression).

-If Model a = Model a+1 , the independant variable could be removed.

-If Model a ≠ Model a+1 , the independent variable could not be removed. 6 Validation of the prediction model (using bootstrap). 7 Comparison of prediction quality between RF_SF, RF&CARCA_SF, and CARCA_SF models (using the following parameters: R², RMSEP, MPE, and AIC).

The point was repeated to the final model.