Chemerin concentration in egg white in layer and broiler hens during the laying period for 2 successive generations.

The genetic selection progress in layers and broilers makes poultry production one of the fastest growing industries. Objectives of the breeding companies are the stability or the increase in the laying rate and the production of viable chicks. New biomarkers are necessary to improve reproductive and egg performances. Chemerin (Chem) produced by oviduct accumulates in egg white (EW). Here, we hypothesized that EW Chem concentration was dependent on the stage of laying and on the breed (layer vs. broiler). In addition, they could be associated to laying performance and fertility parameters. In breeding companies, we collected during 2 successive generations (G0 (mother) and G1 (daughter)) eggs from 100 layers and 100 broilers hens during 5 d at 3 stages: before, after laying peak and at the end of laying period. For each egg, the EW was sampled to measure Chem concentration by ELISA assay. In each generation at the end of laying period, magnums from oviduct, where the EG is formed, were collected in layers and broilers in order to investigate Chem differential expression by RT-qPCR between both breeds. Chem concentration in EW was dependent on the time of laying period and its profile was differently regulated in layers and broilers. Indeed, it increased at the end of laying in layers whereas it decreased after the laying peak in broilers. At the end of laying period, Chem concentration in EW was almost 2-fold higher in layers than in broilers and this was confirmed in both G0 and G1 generations at the Chem mRNA and protein levels in the magnum. For the 2 successive generations, Chem concentration in EW was negatively correlated with the laying rate and the fertility parameter in broiler hens whereas it was negatively correlated with the egg quality (weight of whole egg and weight of albumen) and positively with the fertility rate at some time of laying in layer hens. Taken together, the Chem concentration in EW could be a potential predictive tool for reproductive parameters in genetic selection.

Determination of the elimination half-life of Glyphosate and its main metabolite, AMPA, in chicken plasma.

Glyphosate-based herbicides (GBHs) are the most-used herbicides worldwide. Concerns about their toxicity and ecotoxicity have motivated scientists to assess their potential effects on animals, as well as their toxicokinetic parameters in rats and humans. However, to our knowledge, such data have not been produced for avian models. In this study, toxicokinetic parameters for glyphosate and AMPA were calculated after one unique dietary exposure (40 mg of glyphosate equivalent per kg) and one unique intravenous injection of a GBH, in hens and roosters respectively. Non compartmental analysis was used to show the evolution of glyphosate and AMPA plasma concentrations over time. After one unique intravenous injection of a glyphosate-based herbicide, glyphosate and AMPA were quickly eliminated from plasma and were poorly distributed (Vssglyphosate = 0.30 L/kg). Their terminal half-lives are 4.7 h and 8.10 h, respectively. After dietary exposure, glyphosate and AMPA followed a 6 h absorption phase followed by a 42 h elimination phase. They were poorly distributed (Vssglyphosate = 0.00562 L/kg), and their maximum concentrations (Cmax) were 21285 µg/L and 108 µg/L, respectively. Their terminal elimination half-lives were 8.94 h and 6.93 h, respectively. Taken together, this study provides new data on the elimination rate and approximate biological half-life range of glyphosate in birds.

Chronic dietary exposure to a glyphosate-based herbicide in broiler hens has long-term impacts on the progeny metabolism.

Glyphosate-based herbicides (GBH) are the most commonly used herbicides in agriculture. Several studies reported possible adverse effects on human and animal models after a GBH exposure. However, the effects of a temporary maternal exposure on the progeny have been poorly documented, especially in avian models. We investigated the effects of a hen chronic dietary exposure to a GBH on the progeny, obtained during the period following the withdrawal of GBH from the diet. Hens were exposed to a GBH via their food for 6 wk, after which the GBH was removed from their food. Eggs from these hens were collected 3 wk after the GBH was withdrawn for 1 wk. We monitored the growth performances, metabolic parameters, and behavior from the progeny of the hens (Ex-GBH chicks, n = 186) and compared them with those of unexposed control-hen progeny (CT chicks, n = 213). Ex-GBH chicks were more likely to explore their new environment than CT chicks during the open-field test. In addition, they had an increased fattening and blood triglycerides level, whereas their food consumption was similar to CT chicks. Quantitative PCR on the chemerin system and FASN in chicks livers indicate a transcriptional activity in favor of fatty acid synthesis, and lipidomic analysis on chicks abdominal adipose tissue reveal a global increase in monounsaturated fatty acid and a global decrease in polyunsaturated fatty acids. Seven genes involved in the synthesis of fatty acids were identified with the open access LIPIDMAP software, and their disturbance in Ex-GBH chicks was confirmed via qPCR. Taken together, these results suggest that the progeny of hens temporarily exposed to a GBH are more likely to fatten, even with a balanced diet. The removal of GBH from their contaminated environment would therefore not be sufficient to completely restore their health, has it could induce transgenerational effects.

Triazole pesticides exposure impaired steroidogenesis associated to an increase in AHR and CAR expression in testis and altered sperm parameters in chicken.

Since several decades, we observe the decline of various bird populations that could be partly linked to the agricultural intensification and the use of large amount of pesticides. Even if triazoles compounds are the most widely used fungicides, their effects on the reproductive parameters in birds are not clearly known. In the present study, we investigated the in vitro effects of 8 triazoles compounds alone (propiconazole (PP, from 0 to 10 µM), prothioconazole (PT), epoxiconazole (Epox), tetraconazole (TT), tebuconazole (TB), difenoconazole (Dif), cyproconazole (Cypro), metconazole (MC) (from 0 to 1 mM)) on the male chicken reproductive functions by using testis explants, primary Sertoli cells and sperm samples. In testis, all triazoles at the higher concentrations for 48 h inhibited lactate and testosterone secretion mostly in association with reduced expression of HSD3B and/or STAR mRNA levels. These data were also associated with increased expression of the nuclear receptors Aryl Hydrocarbon Receptor (AHR) and Constitutive Androstane Receptor (CAR) mRNA levels in testis and for all triazoles except for PP a reduction in Sertoli cell viability. When focusing on the sperm parameters, we demonstrated that most of the triazoles (MC, Epox, Dif, TB, TT and Cypro) at 0.1 or 1 mM for either 2, 12 or 24 min of exposure decreased sperm motility and velocity and increased the percentage of spermatozoa abnormal morphology. At the opposite, PP increased sperm motility in a dose dependent manner after 2 min of exposure whereas no significant effect was observed in response to PT whatever the dose and the time of exposure. Moreover, these effects were associated with an increase in the production of reactive oxygen species in spermatozoa. Taken together, most of the triazoles compounds impair testis steroidogenesis and semen parameters potentially through an increase in AHR and CAR expression and in oxidative stress, respectively. Data Availability Statement: All the data will be available.

Chronic dietary exposure to a glyphosate-based herbicide results in total or partial reversibility of plasma oxidative stress, cecal microbiota abundance and short-chain fatty acid composition in broiler hens.

Glyphosate-based herbicides (GBHs) are massively used in agriculture. However, few studies have investigated the effects of glyphosate-based herbicides on avian species although they are largely exposed via their food. Here, we investigated the potential reversibility of the effects of chronic dietary exposure to glyphosate-based herbicides in broiler hens. For 42 days, we exposed 32-week-old hens to glyphosate-based herbicides via their food (47 mg/kg/day glyphosate equivalent, glyphosate-based herbicides, n = 75) corresponding to half glyphosate's no-observed-adverse-effect-level in birds. We compared their performance to that of 75 control animals (CT). Both groups (glyphosate-based herbicides and control animals) were then fed for 28 additional days without glyphosate-based herbicides exposure (Ex-glyphosate-based herbicides and Ex-control animals). Glyphosate-based herbicides temporarily increased the plasma glyphosate and AMPA (aminomethylphosphonic acid) concentrations. Glyphosate and aminomethylphosphonic acid mostly accumulated in the liver and to a lesser extent in the leg muscle and abdominal adipose tissue. Glyphosate-based herbicides also temporarily increased the gizzard weight and plasma oxidative stress monitored by TBARS (thiobarbituric acid reactive substances). Glyphosate-based herbicides temporarily decreased the cecal concentrations of propionate, isobutyrate and propionate but acetate and valerate were durably reduced. The cecal microbiome was also durably affected since glyphosate-based herbicides inhibited Barnesiella and favored Alloprevotella. Body weight, fattening, food intake and feeding behavior as well as plasma lipid and uric acid were unaffected by glyphosate-based herbicides. Taken together, our results show possible disturbances of the cecal microbiota associated with plasma oxidative stress and accumulation of glyphosate in metabolic tissues in response to dietary glyphosate-based herbicides exposure in broiler hens. Luckily, glyphosate-based herbicides at this concentration does not hamper growth and most of the effects on the phenotypes are reversible.

Chronic dietary exposure to a glyphosate-based herbicide results in reversible increase early embryo mortality in chicken.

Glyphosate (Gly) is the active molecule of non-selective herbicides used in conventional agriculture. Some evidence shows that exposure to Glyphosate-Based Herbicides (GBH) can affect both male and female fertility in animal models. However, few data exist on birds that can be easily exposed through their cereal-based diet. To our knowledge, there are no current studies on the effects of chronic dietary exposure to GBH and the potential reversibility on the fertility and embryo development in chickens. In our protocol, hens (32 weeks-old) were exposed to GBH (47 mg kg-1/day-1 glyphosate equivalent corresponding to half of the No-Observed-Adverse-Effect-Level (NOAEL) as defined by European Food Safety Authority in birds, GBH group (GBH), n = 75) or not (Control group (CT), n = 75) for 6 weeks. Then, both CT and GBH groups were fed for 5 more weeks without GBH exposure. During these two periods, we investigated the consequences on the egg performance and quality, fertilization rate, embryo development, and viability of offspring. Despite the accumulation of Gly and its metabolite aminomethylphosphonic acid (AMPA) in the hen blood plasma, the body weight and laying rate were similar in GBH and CT animals. We observed from the 4th day of exposure an accumulation of Gly (but not AMPA) only in the yolk of the eggs produced by the exposed hens. After artificial insemination of the hens followed by eggs incubation, we showed a strong significant early embryonic mortality level in GBH compared to CT animals (78 ± 2 % vs 2.5 ± 0.3 %, p < 0.0001) with embryo death mainly occurring on the third day of incubation. By using computed tomography (CT) and magnetic resonance imaging (MRI) tools, we noted a significant delay in the embryo development of GBH survivors at 15 days with a reduction by half of the embryo volume and some disturbances in the calculated volumes of the embryonic annexes. At 20 days of incubation, we showed a reduction in the length of the tibia and in the volume of the soft tissues whereas the skeleton volume was increased in GBH chicks. The vast majority of these phenotypes disappeared two weeks after an arrest of the GBH maternal dietary exposure. Taken together, the dietary chronic exposure of broiler hens to GBH at a Gly equivalent concentration lower than NOAEL induces an accumulation of Gly in the egg yolk resulting in severe early embryonic mortality and a delayed embryonic development in survivors that were abolished two weeks after the end of GBH exposure.