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Grassland Fabaceae grown under contrasted phosphorus supply induced changes in rhizospheric soil phosphatase activity

Florian

  Fort, Pablo Cruz, Stroia Ciprian, Claire Jouany To cite this version: Florian Fort, Pablo Cruz, Stroia Ciprian, Claire Jouany. Grassland Fabaceae grown under contrasted phosphorus supply induced changes in rhizospheric soil phosphatase activity. Phosphorus in Soils and Plants: 5. International Symposium, Aug 2014, Montpellier, France. 148 p., 2014, PSP5 2014. Facing Phosphorus Scarcity. hal-02740155


Odile Berge
email: odile.berge@avignon.inra.fr

Caroline L Monteil

Claudia Bartoli

Caroline Guilbaud

Charlotte Chandeysson

Benoit Borschinger

David C Sands

Cindy E Morris

Benoit Borshinger

A broad and operational classification framework to address the ecology of Pseudomonas syringae populations

Keywords: Phylogeny, data base, classification tool, citrate synthase, specific PCR. Thematic Area: b) Evolution, taxonomy and systematics

d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.


domain: sdv sde info

text:
Emmanuelle Garrigues
email: garrigues.emmanuelle@wanadoo.fr

Michael S Corson

Aurélie Wilfart

Safya Menasseri

Effect of on-farm biogas production on impacts of pig production in Brittany, France

Keywords: anaerobic digestion, pig production, soil organic matter change

In the context of climate change and non-renewable energy depletion, the transition toward increasing the contribution of renewable energy requires insight into environmental consequences of such energy production, such as anaerobic digestion (AD). In a pig farm producing crops used as ingredients for pig feed, biomass (fertilized with pig manure), crop residues and intercrops are highly valuable substrates for AD. Thus, the aim of this work was to assess the influence of on-farm digestion of pig slurry to produce bio-energy on environmental impacts of pig production from a life cycle perspective. This system allows maximum autonomy for the farmer, regardless of the availability of digester nutrients. It had lower negative impacts for most impact categories than a more energy-dependent system, even for hotspot impacts of climate change and cumulative energy demand. More accurate data about carbon mineralization of digestates are necessary to make conclusions about potential impacts on soil organic matter dynamics.

Introduction

In the context of climate change and non-renewable energy depletion, the demand for renewable energy is rising, and the European Union aims to obtain 20% of its energy from renewable sources by 2020 [START_REF] Eu | Directives on the promotion of the use of energy from renewable sources[END_REF]. This transition requires insight into environmental consequences, such as climate change (CC) and cumulative energy demand (CED), of renewable energy production. Change in soil organic matter (SOM) is also a hotspot indicator for soil quality (Garrigues et al. 2012) in the case of bio-energy produced from biomass by anaerobic digestion (AD) in the form of heat and electricity. The product that remains after AD is digestate, which can be recycled as organic fertilizer for crop cultivation. On a pig farm in which the main crops used as ingredients for pig feed are produced on the farm, biomass (fertilized with pig manure), crop residues and intercrops are highly valuable substrates for AD. Thus, the aim of this work was to assess the influence of on-farm co-digestion of pig slurry to produce bio-energy on environmental impacts of pig production from a life cycle assessment (LCA) perspective.

Methods

System definition

The agricultural system is assessed via its function of food production. System boundaries of the pig breeder/fattener system are from cradle to the farm gate. The system includes infrastructure, inputs, related resources and emissions for pig production and the crops used as ingredients in the pig feed. For crops used as pig-feed ingredients, the main crop rotation in its region of origin was assumed. For crops produced on the pig farm, crop rotations were considered in greater detail. Temporal system boundaries of crop rotations end with the harvest of the crop analyzed and begin after the harvest of the preceding crop. The functional unit is 1 kg of pig liveweight produced. Impact categories assessed were those of the CML-IA, plus CED and two soil-quality indicators: compaction and SOM change (Garrigues et al. 2012). Figure 1. System boundaries for baseline (BASE) and anaerobic digestion (AD) scenarios

Definition of scenarios

We compared two scenarios (Fig. 1): (1) standard manure storage and spreading on a representative pig farm in Brittany, France (BASE scenario), and (2) the same pig farm with a 50 kW AD plant with digestate spreading on fields instead of slurry (AD scenario). The representative farm produces 4800 pigs per year with 225 permanent sows. Maize, wheat and barley are produced on 115 ha with phacelia as an intercrop. Four rotations are represented: wheat-maize and wheat-barley-maize on 48 ha each, wheat-maize-maize on 15 ha and maize monoculture on 4 ha. In the AD scenario, oats and triticale are also grown as intercrops with phacelia to feed the AD plant (Table 2). Fertilizer applications (mineral and organic) were calculated to maintain yield and to prevent pollution risk. Characteristics of the pig farm (e.g., volume of pig production, area, crops) were based on examples of existing pig farms in Brittany that remained economically viable after adding AD to the farm (Brittany Chamber of Agriculture, pers. comm.). Pig production in the breeder/fattener system uses seven different feeds, with compositions defined by the French Pork and Pig Institute (IFIP) according to the pig-production stage (Table 1). The farmer fabricates all feeds on the farm. All crop production is used to feed the sows, piglets and pigs and represents 88% of the maize, 82% of the barley and 70% of the wheat needed for the feeds. The rest of the ingredients are bought on national and international markets (Table 1).

AD scenario

In seeking maximum autonomy for the farmer, dimensions of the AD plant (energy produced and substrate quantities needed) aim for economic viability of the pig farm: no need to import substrates for AD other than those produced on the farm and spreading of all digestate produced on farm crops as fertilizer.

The AD is operated at a mesophilic temperature (around 35°C) with a hydraulic retention time of 66 days. CH 4 production from the AD is 110,832 m 3 /year, with an electricity-production capacity of 50 kW and energy efficiency of 36%. Operating the AD requires 3% of the electricity produced and consumes 36% of the heat produced. The heat produced covers all heating needs of pig buildings and provides a surplus in summer. This scenario reflects simple biogas installations, which produce less electricity but also cost less to install. To obtain a liquid rather than solid digestate, not all of the available straw and maize stalks are placed into the digester. The digestate is liquid enough (5.8% DM) to be spread as fertilizer, in the same way that slurry is spread in the BASE scenario. In the AD scenario, slurry and digestate are stored separately in covered concrete tanks, and the remaining 50% of the wheat straw is sold. CH 4 and N 2 O emissions of the AD plant (storage and digestion) were calculated with the DIGES tool [START_REF] Gac | DIGES -DIgestion anaérobie et Gaz à Effet de Serre Cemagref[END_REF]. Since emission factors for digestate applied to fields were not available, we assumed them to be the same as those for pig slurry. In the BASE scenario, slurry is stored in and open concrete tank, and 100% of the wheat straw is sold. During storage, nutrient leaching from the slurry or digestate is assumed to be negligible in both scenarios.

Soil carbon change modeling

RothC (version 26.3) simulates dynamics of organic carbon (C) in soil [START_REF] Coleman | Simulating trends in soil organic carbon in long-term experiments using RothC-26.3[END_REF]Coleman and Jenkinson 2008). The effects of soil type, temperature, moisture content and plant cover are considered in the turnover process. Soil organic C is split into four active compartments and a small amount of inert organic matter (IOM). The four active compartments are decomposable plant material (DPM), resistant plant material (RPM), microbial biomass (BIO) and humified organic matter (HUM). When exogenous organic matter is added to the soil, it is split between the DPM, RPM and possibly HUM pools according to partition coefficients, such We used DPM of 63.9% and RPM of 31.7% for slurry and DPM of 29.5% and RPM of 58.5% for digestate. We simulated 20 years of the same management practice and divided the total change in soil organic C by 20 to provide the mean rate over one year. When analyzing crop rotations, temporal system boundaries differed from those of individual crops, for which the C brought to the soil by crop residues was considered from just after the harvest of the crop of interest (when residues are left in the soil) to the harvest of the following crop. We thus followed back-effects of the C supplied. The change in soil C could be positive or negative, indicating soil C storage or loss, respectively.

Results

Table 3. Potential impacts of the (BASE)line and anerobic digestion (AD) scenarios per kg of pig liveweight according to the CML-IA method. LCA of the two scenarios showed lower environmental impacts per kg of pig liveweight of the farm with AD (Table 3). Installation of an AD plant reduced CC by 1.9% (BASE: 1.90 kg CO 2 -eq/kg; AD: 1.86 kg CO 2 -eq/kg) and CED by 8.1% (BASE: 11.84 MJ/kg; AD: 10.88 MJ/kg). SOM was sequestered in both scenarios (positive impacts) despite less soil C storage when straw was exported compared to a scenario (results not shown here) in which straw was left on the soil. The BASE scenario sequestered a mean of 13.5 kg C/kg and the AD scenario 11.2 kg C/kg. The AD scenario had higher acidification and eutrophication impacts than the BASE scenario (by 2.1 and 2.5% respectively). The greatest increase in impact due to the installation of an AD plant was for soil compaction, which increased by 36.4%. The AD scenario had lower impacts than the BASE scenario for the other categories.

Discussion

Introducing biogas technology in a pig farm in Brittany reduced greenhouse gas emissions, mainly by replacing natural gas for heating piglet nurseries. In France, where most electricity is produced by nuclear energy, CC impacts from electricity production were similar for both scenarios. Even though the AD plant studied was small, CED decreased due to direct production and use of heat and electricity.

The increase in SOM was lower in the AD scenario than the BASE scenario. AD's digestate has a lower C content than the substrates used to create it because of the loss of C via CH 4 , but it has greater stability, which decreases long-term loss of SOM. In a Danish study [START_REF] Thomsen | Carbon dynamics and retention in soil after anaerobic digestion of dairy cattle feed and faeces[END_REF], a three-pool model used to simulate Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector C mineralization predicted similar long-term C sequestration in soil for initial turnover of plant biomass in the soil, ruminant digestive tracts, an AD plant or a combination of the latter two. In that study, C pools in the model were calibrated with laboratory incubations. In our study, the RothC model was initialized with pedotransfer functions. Although both scenarios sequester C, the lower C sequestration due to spreading digestate instead of slurry can be compensated by changing straw management: C sequestration was 19.5 kg C/kg (74% higher) if all straw was returned to the soil in the AD scenario.

Adopting AD technology on a pig farm appears to increase compaction due to the greater number of field operations required for the new intercrops grown to feed the AD plant. Since the compaction indicator only considers neutral (plowing) or negative impacts of field passes, the more field operations, the higher the predicted compaction [START_REF] Garrigues | Development of a soil compaction indicator in life cycle assessment[END_REF]. Furthermore, the new operations occurred when soil water content was high (spring and autumn), thereby increasing compaction risk. The compaction indicator represents the potential impact well if these practices are performed every year. Indirect implications of soil compaction, such as lower future yields, should not be neglected, but crop rotations should decrease this risk. Despite this, AD of slurry, straw and intercrops is well accepted in France. Replacing the intercrops with crops to feed the digester would probably decrease compaction and increase efficiency of the AD, but this practice is not currently accepted in France. A sensitivity analysis is planned to assess the relative influence of farm and AD plant characteristics.

Conclusion

Installation of a small AD plant on a pig farm producing most of the ingredients in its animal feed provides maximum autonomy for the farmer, who does not have to depend on the availability of plant substrates for AD. The AD system tended to have lower environmental impacts than a more energy-dependent system, even for the hotspot impacts of climate change and cumulative energy demand. Careful attention must be paid to SOM management through C amendment with digestate and straw. Digestates are quite new types of exogenous organic matter with a wide diversity of C mineralization characteristics depending on the plant substrate. More accurate data about carbon mineralization of digestates are necessary to make conclusions about potential impacts on SOM dynamics.

2. 3 .

 3 Life cycle inventory assumptions and model used for SOM change 2.3.1. Composition of pig feed in the two scenarios

  based on Olympic mean price from[START_REF] Gac | DIGES -DIgestion anaérobie et Gaz à Effet de Serre Cemagref[END_REF] -2010[START_REF] Ista Mielke Gmbh | Indicator of potential residual carbon in soils after exogenous organic matter application[END_REF][START_REF]Germany ISTA (Information Science, Technology and Applications[END_REF].

Table 1 .

 1 Ingredient composition (percentage by mass) and sources of representative pig feed produced in Brittany.

	Ingredient	Maize	Wheat	Wheat middlings	Barley	Rape-seed oil	Rapeseed cake	Soya cake	Sunflower cake	Sugarbeet pulp
	Origin	France (Brittany)	France (Brittany)	France (Brittany)	France (Brittany)	Brazil (Santa Catarina)	Argentina (Balcarce)	France (Picardy)
	Source crop	Maize	Winter wheat	Barley	Rapeseed	Soya	Sunflower Sugarbeet
	Economic allocation a (%)	100.0	100.0	14.0	100.0	75.6	24.4	66.0	37.6	15.6
	Pregnant sow feed (%)	6.8	40.0	3.2	30.0	0	6.7	0	5.0	5.0
	Lactating sow feed (%)	12.7	30.0	0	32.0	0	5.7	13.0	2.0	1.0
	Piglet prestarter feed (%)	0	61.9	0	0	4.6	0	27.6	0	0
	Piglet starter feed (%)

Table 2 .

 2 Substrates of the anaerobic digestion (AD) plant and their organic matter (OM) before and after AD

	Substrates	% of substrate produced	t/year	OM before	OM after digestion
		on-farm used for digestion		digestion (t)	and storage (t)
	Pig slurry	100	207	147	100
	Wheat chaff	100	71	65	31
	Barley chaff	100	17	15	7
	Grass silage	100	12	11	4
	Oats (intercrop)	100	56	53	9
	Triticale (intercrop)	100	60	56	13
	Barley straw	50	28	26	15
	Maize stalks	33	64	59	34

Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector as

  DPM/RPM. For crop residues, we used a DPM/RPM ratio of 1.44, i.e. DPM of 59% and RPM of 41%. For slurry and digestate, DPM and RPM was calculated from their Van Soest biochemical fractions via an indicator of remaining organic C (I ROC )[START_REF] Ista Mielke Gmbh | Indicator of potential residual carbon in soils after exogenous organic matter application[END_REF]) based on equations developed by[START_REF] Peltre | RothC simulation of carbon accumulation in soil after repeated application of widely different organic amendments[END_REF]

	DPM		254 . 1 		I	ROC		922 . 115	Eq. 1
	RPM		979 . 0		I	ROC		928 . 8	Eq. 2

Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector


I Pacheco

Leandro De Oliveira-Lino

A Ciacciulli

M Lama

S Foschi

F Faoro

Veronique Signoret

D Bassi

Bénédicte Quilot-Turion

Assessing brown rot resistance in peach fruit

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

Assessing brown rot resistance in peach fruit. Pacheco I., De Oliveira Lino L., Ciacciulli A., Lama M., Foschi S., Faoro F., Signoret V., Bassi D., Quilot-Turion B. Brown rot caused by Monilinia spp. (BR) is an economically important disease in stone fruits since it causes dramatic in the whole production chain. The availability of standard methods to screen the resistance to this pathogen in fruit constitutes a basis for the identification of suitable parents for efficient breeding programs to improve this trait. Previous works have highlighted variability in levels of resistance in the germplasm and some crosses, suggesting that this trait has a genetic component. Nevertheless, this trait is also strongly affected by environmental conditions (climate and agronomical practices) and fruit macroscopic characteristics (or "fruit factors", such as maturity date, developmental stage/maturity level at harvest, fruit size, cuticular and epidermal micro-crack incidence, etc). Therefore the generation of screening protocols for BR resistance that allow a clear genetic dissection of this trait is a challenging activity. In Fruit Breedomics, two methods have been developed to estimate BR resistance, both based on artificial inoculation of Monilinia laxa: i) a fast method to screen BR impact on tens of seedlings per day directly on the field, and ii) a laboratory method allowing to follow infection progression. These protocols are being used to phenotype progenies, generating data suitable for QTL analysis and marker discovery. Besides, other experiments have been performed to find out fruit characteristics linked to BR resistance. Correlations have been found in different cultivars and selections with fruit factors, such as cuticular conductance along fruit development, biochemical composition of the cuticle, microscopic features on infected fruit.


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  Influence of somatic cell count and trace element supplementation on lactation performance and DNA methylation in PBMC and MEC during early lactation in Holstein dairy cows Marion Boutinaud, Maxime Gasselin, J. Zawadzki, B. Pount, Michel Fargetton, Hélène Kiefer, Hélène Jammes To cite this version: Marion Boutinaud, Maxime Gasselin, J. Zawadzki, B. Pount, Michel Fargetton, et al.. Influence of somatic cell count and trace element supplementation on lactation performance and DNA methylation in PBMC and MEC during early lactation in Holstein dairy cows. 6. IDF international mastitis conference, International Dairy Federation (IDF). FRA., Sep 2016, Nantes, France. hal-02740296


Yann H Kerr

Philippe Richaume

Jean-Pierre Pierre Wigneron

Al Bitar Ahmad

Arnaud Mialon

Jennifer Grant

Heather Lawrence

Paolo Ferrazzoli

Rachid Rahmoune

Ali Mahmoodi

Ahmad Al Bitar

Arnaud Mailon

SMOS retrievals of vegetation optical depth over a variety of land use: trials and tribulations

INTRODUCTION

The SMOS mission [START_REF] Kerr | Soil moisture retrieval from space: the Soil Moisture and Ocean Salinity (SMOS) mission[END_REF][START_REF] Kerr | The SMOS Mission: New Tool for Monitoring Key Elements ofthe Global Water Cycle[END_REF] was launched in November 2009 and allows measuring the surface soil moisture over continental land, covering the entire surface in 3 days. The multi-angular algorithm also enables to estimate the vegetation opacity which is directly related to the water content of the canopy.

The algorithm also distinguishes between low vegetation where most of the signal emanates from the leaf and stems of the vegetation and the forests where the signal is mainly linked to the branch biomass at L band. ESA's DPGS (European Space Agency's Data Processing Ground Segment) has been delivering the so called Level 2 products, consisting in ½ orbits data for both products since launch [START_REF] Kerr | The SMOS soil moisture retrieval algorithm[END_REF][START_REF] Kerr | SMOS level 2 processor soil moisture Algorithm Theoretical Basis Document (ATBD), SM-ESL (CBSA)[END_REF].

The CNES (Centre National d'Etudes Spatiales) has developed the CATDS (Centre Aval de Traitement des Données SMOS) ground segment that now provides spatial and temporal synthesis products (referred to as Level 3 products) enabling to better estimate the vegetation opacity ( as well as soil moisture and brightness temperature over land) [START_REF] Kerr | CATDS SMOS L3 soil moisture retrieval processor[END_REF].

After now several years of availability , the soil moisture product is rather robust but the vegetation opacity, either obtained at level 2 or 3 still suffers from several flaws, even if it looks promising.

In this paper we will look at the products and how they are obtained as well as the main results obtained over both low vegetation and forested areas.

DATA SETS

and depicted in table 1.Other data sets are used to compute the retrievals as explained in [START_REF] Kerr | The SMOS soil moisture retrieval algorithm[END_REF][START_REF] Kerr | SMOS level 2 processor soil moisture Algorithm Theoretical Basis Document (ATBD), SM-ESL (CBSA)[END_REF][START_REF] Kerr | CATDS SMOS L3 soil moisture retrieval processor[END_REF] Figure 1 Vegetation optical depth for August 2010 (Level 3 product)

METHODOLOGY

The approaches are fully described in references [START_REF] Kerr | The SMOS soil moisture retrieval algorithm[END_REF][START_REF] Kerr | SMOS level 2 processor soil moisture Algorithm Theoretical Basis Document (ATBD), SM-ESL (CBSA)[END_REF][START_REF] Kerr | CATDS SMOS L3 soil moisture retrieval processor[END_REF] and are based on the L-MEB model [START_REF] Wigneron | L-band Microwave Emission of the Biosphere (L-MEB) Model: description and calibration against experimental data sets over crop fields[END_REF]. For instance, first results obtained in the central plain of the USA evaluated the link between opacity and vegetation indices (NDVI, LAI, NDWI). In particular the study confirmed the linear relationship used in the algorithm: TAU = b' LAI + b''; with b' = 0.06.

Over forested areas the basic algorithm [START_REF] Ferrazzoli | Simulating L-band emission of forests in view of future satellite applications[END_REF] was improved on several occasions, the most advanced running in version 600 of the level 2 algorithm and described in [START_REF] Rahmoune | SMOS Level 2 retrieval algorithm over forests: Description and generation of global maps[END_REF]. A global map is shown on figure 2.

We can clearly see the different large forest bodies in either the high latitude areas or in the tropical regions. The results were validated against a set of ground sites but the only real conclusive result was obtained with the comparison with Icesat vegetation height estimates [START_REF] Rahmoune | SMOS Level 2 retrieval algorithm over forests: Description and generation of global maps[END_REF].

RESULTS AND DISCUSSION

If over forest the results do look very satisfactory it is obvious that validation is somewhat difficult as very few ground datasets are available. To circumvent this issue we have performed several validation exercises. They are based either on the relationship between canopy height (from IceSAT) which is assumed to be proportional -per forest type -to the branch volume and hence opacity or on the accuracy of the Soil moisture estimate under the canopy. For the latter we used the available datasets and in particular the Scan Snotel networks [START_REF] Al Bitar | Evaluation of SMOS Soil Moisture Products Over Continental U.S. Using the SCAN/SNOTEL Network[END_REF] using soil moisture as an indicator of accuracy. For low vegetation results were more difficult to access as the retrieved vegetation opacities tend to be extremely noisy. A large part of the noise is linked to either low level Radio frequency interferences or spatial calibration errors of level 1 and thus it is expected that the retrievals will be improved. Moreover a number of studies are currently analyzing the modelling itself and further improvements are expected (in particular with respect to the roughness opacity coupling).

CONCLUSION AND PERSPECTIVES

The new version 600 available early 2014 should provide a significant improvement on vegetation opacity retrievals for both forest and low vegetation. It is however expected that some issues will remain linked to inaccuracies in the land cover classification errors or roughness poor estimates. To circumvent these issues, novel studies are being initiated including the use of a two stream approach rather than the 0 th order scattering model currently used. It is also considered to develop a specific, vegetation centered, vegetation retrieval scheme.

Figure 2

 2 Figure 2 Vegetation opacities retrieved with new algorithm over forested areas (and routine algorithm over low vegetation)

Table 1 -Overview of SMOS VOD data sets.

 1

		Level 2	Level 2	Level 3	Level 3
		low vegetation	Forest	Low vegetation	forest
	Reference	[3]	[8]	[5]	[4]
	Product sampling	15 km	15 km	25 km	25 km
	Algorithm base τ, ω	τ,ω	τ, ω	τ, ω
	Approach	Current files		Multi orbit
	Uses	parameters	LAI max	Parameters	LAI max

Acknowledgements: The work was funded by ESA (level 2 algorithm development) and CNES (CATDS and TOSCA programme)


William Dudefoi

Hélène Terrisse

Mireille Richard-Plouet

Bernard Humbert

E Gautron

Marie-Hélène Ropers
email: marie-helene.ropers@nantes.inra.fr

M-H Ropers

Characterization of TiO2 nanoparticles as food additive

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Titanium dioxide (TiO 2 ) is a white metal oxide commonly used as a white pigment in various applications such as paints, cosmetic but also food products where it constitutes the coating of sweets and chewing-gum. Due to the classification of TiO 2 nanoparticles as potentially harmful for humans by inhalation, the toxicity after ingestion raised concerns and needs to be evaluated. However, the physicochemical characteristics of food grade TiO 2 are poorly known.

In this study, we studied several food grade TiO 2 samples (size distribution, shape, crystallinity, reactivity, surface properties) and evaluated whether they are similar to the wellknown P25 particles that served as reference for numerous toxicological studies.

The main result of our study is that E171 and P25 are different particles, with different compositions and surface chemistry. TEM analysis confirmed the presence of nanoparticles in P25 and in E171 samples, but the primary sizes and the percentage of nano-sized particles were different: 23 nm with 100% of nanoparticles in P25 and 131 nm with 26% of nanoparticles in E171. Isoelectric points were assessed by zeta potential measurements and were determined at pH 6.2 for P25 and between pH 2 and pH 4.2 for E171 depending on suppliers. Particle size distribution analyses showed different agglomeration behavior: E171 tended to form larger agglomerates at pH < 5 whereas P25 formed larger agglomerates at pH > 5. XRD, XPS, FT-RAMAN, DRIFTS, surface specific area analysis and ICP-AES analysis showed P25 particles are a mixture 75/25 of rutile/anatase with a pure and reactive surface, whereas E171 is a 100% anatase, coated with some organic impurities, and sometimes silicon and aluminum. Finally, this work confirms the recent paper of Yang et al., 2014(Environ. Si. Tech. 2014, 48, 6391) and provides some more data on food grade TiO 2 surface chemistry including specific surface area and DRIFTS measurements but also size distribution evolution from pH 1 to pH 9. Some variability was also found among food grade TiO 2 samples, leading us to strongly recommend researchers to properly characterize their samples before each of their toxicological studies. In any case, using Degussa P25 particles does not appear to be the most reliable model to study the fate of food grade TiO2 in the gastro-intestinal tract.

Acknowledgements

This work has been carried out in the framework of the Labex Serenade (ANR-11-LABX-0064) and of the A*MIDEX project (ANR-11-IDEX-0001-02), funded by the «Investissements d'Avenir» French Government program managed by the French National Research Agency (ANR).


domain: shs sdv info

text:
Adeline Bougouin

Anne Ferlay

Michel M Doreau

Yvanne Rochette

Sylvie Rudel

Clothilde Lascoux

Cécile Martin

Effect of concentrate type (starch vs. fiber) and bicarbonate addition in grass silage-based diets on performance, diet digestibility and enteric methane emissions in lactating dairy cows

Keywords: concentrate type, dairy cow, methane emissions

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

Effect of concentrate type (starch vs. fiber) and bicarbonate addition in grass silage-based diets on performance, diet digestibility and enteric methane emissions in lactating dairy cows.


Sylvia Anton

Fabienne Dupuy

Nina Deisig

Michel Renou

Sex pheromones and flower odours: how a male moth finds a female in a noisy environment

Moths, like many other insects, communicate using olfactory cues. Females produce a species-specific sex pheromone, which is detected by males over large distances. Male moths also use flower odours to find food or may use host plant odours as additional cues to localize females. Plant-derived odours, present in large amounts in a natural environment, may, however, also represent an olfactory noise, possibly disturbing specific communication. In the noctuid moth Agrotis ipsilon , virgin male attraction to the sex pheromone increases when presented together with a flower odour. However, different plant compounds added to the pheromone during orientation can have different behavioural effects in this species. To elucidate the neuronal mechanisms underlying behavioural effects, we investigated peripheral and central nervous processing of pheromone-plant odour mixtures applied simultaneously or as a background stimulus. Heptanal, a major component of linden flowers, elicited unexpectedly excitatory responses in pheromone-specific olfactory receptor neurons and inhibited responses when added to the pheromone. Extracellular single sensillum recordings revealed that pheromone responses in these olfactory receptor neurons were decreased when applied in a background of heptanal. Pheromone responses in the male-specific part of the antennal lobe, the macroglomerular complex (MGC) were also reduced when applied together with heptanal during optical imaging recordings. Intracellular and extracellular MGC-recordings revealed a reduced response to the pheromone-heptanal mixture as compared to the pheromone alone in a majority of olfactory neurons. These neurons improved their capacity to follow stimulus pulses upon mixture stimulation. In the plant odour specific part of the olfactory system, no interaction of the sex pheromone with plant odours was found at the antennal level. Plant-specific olfactory receptor neurons did not respond to the pheromone and the pheromone did not modify plant odour responses. This lack of a mixture interaction persisted up to the antennal lobe input level. Calcium responses within the so-called ordinary glomeruli, serving plant odour processing, were not modified by the pheromone. A large proportion of antennal lobe neurons with dendritic arborisations in the ordinary glomeruli, however, responded more strongly to the mixture of heptanal and pheromone than to the pheromone alone, even though only weak responses to the pheromone alone had been observed. Peripheral interactions at the receptor level within the pheromone subsystem and interactions during central processing between pheromone and general odorant subsystems result thus in complex integration of both informations.