Biologie des Oiseaux et Aviculture

Heat stress reduces fetal growth in late gestation in cattle, driven by shifts in placental form and function. Sheep are short-day breeders, but they are also bred off-season, allowing late summer lambing, which is associated with heat stress exposure in late pregnancy. Citrulline is known to induce nitric oxide release and vasodilatation and may not be degraded by the rumen, but its impacts on placental function are unknown. This study aimed to: 1) evaluate the effects of late gestation heat stress on placental/fetal development in ewes; and 2) evaluate if citrulline supplementation mitigates heat stress impacts. To that end, 28 pregnant ewes were randomly assigned to each treatment in environmental chambers: control (CN; n=14, 18°C) or heat stress (HT; n=14: 28°C daytime and 25°C nighttime) during their last month of gestation. Within temperatures, animals received citrulline (0.5% dry matter intake (DMI), CT) or not (NO), resulting in a 2×2 factorial design: CNCT, CNNO, HTCT, and HTNO (n=7/trt). Respiration rates (RR) and rectal temperature (RT) were measured once weekly and placental perfusion was estimated by quantitative power Doppler ultrasonography at the beginning and 15 days after the start of the experiment. Gestation length (GL) and lamb birth weight (BW) were recorded. Placentas were collected at spontaneous delivery (3±0.66h postpartum). Data analysis used the GLIMMIX procedure in SAS with fixed effects of ewe, lamb sex, category, treatments, and their interaction. In ewes, HT increased RR, whereas CT decreased RT in both treatments. HT decreased GL and lamb BW tended to be lower in the HTCT group. Placental morphology did not differ among treatments, but female twins had greater cotyledon number and lower placental efficiency. In conclusion, exposure of ewes to HT during late gestation reduced GL, confirming observations in cattle, and CT tended to reduce BW in heat stress conditions. Further investigations are ongoing in placental function and transcriptomics are currently being evaluated.

Abstract This study explored the impact of incorporating Polygonatum sibiricum polysaccharide (PSP) into broilers’ diets on their growth, serum mineral levels, tibia characteristics, and nutrient digestibility. A total of 240 day-old male Ross-308 broiler chicks were randomly divided into three experimental groups, each consisting of 8 replicates of 10 birds. The birds were fed diets supplemented with PSP at three levels: 0, 400, and 800 mg·kg −1 , denoted as control, 400PSP, and 800PSP, respectively. Notably, the 800PSP group exhibited a linear improvement in feed conversion ratio and weight gain at 35 days of age. Crude protein and calcium digestibility were improved (P>0.05) by PSP inclusion. The PSP addition did not influence the carcass traits, except for the relative weight of pectoral muscle, which increased linearly (P>0.05) in the 800PSP group. Immune organ indexes exhibited a linear increase (P>0.05) in the PSP-fed groups. There were no notable changes in hepatic and renal function biomarkers at 21 and 35 days of age. However, at 35 days of age, the serum lipid profile was affected, as linear and quadratic reductions (P>0.05) in the concentrations of cholesterol, LDL and HDL were noticed. On day 21 of age, serum calcium, potassium, and iron levels exhibited linear increases (P>0.05) in the 800PSP group. Moreover, the tibia ash content at 21 and 35 days of age increased linearly and quadratically (P>0.05) in the 400PSP and 800PSP groups. In conclusion, incorporating PSP in broilers’ diets improved their growth, tibia ash content, serum minerals and lipid profile, and nutrient digestibility, particularly at the 800 mg·kg −1 level.

Equines are parasitized by complex communities of Strongylidae (Nematoda) comprising multi-species infections. Currently, Cyathostominae are most prevalent, while Strongylus species are only rarely detected. Since eggs and, in most cases, infective larvae cannot be differentiated to species level, except for Strongylus spp., species-specific knowledge of the pathology, epidemiology and ecology of these parasitic nematodes is limited. Reference sequence data for several cyathostomin species are limited or missing. Deep amplicon sequencing of internal transcribed spacer 2 (ITS-2) regions of nematodes has been used in equines previously, although barcoding studies demonstrated a better species resolution for the cytochrome c oxidase subunit I (COI) region. The present study introduces a nemabiome method based on sequencing of COI fragments. This method was applied to compare third stage larvae, representing strongyle communities, derived from regularly treated (RT) and never treated (NT) equine populations from Brazil, France (only RT), Germany, Ukraine, the UK, and the USA. Samples were predominantly from horses, but some were obtained from Przewalski's horses (Ukraine), donkeys (Germany, Ukraine) and kulans (Ukraine). Most sequence reads (87.7%) were identified to species level, but unclassified reads occurred more frequently in donkeys and kulans than horses. No obvious difference in species diversity and richness was observed between RT and NT equines. However, there were significant differences in species composition between the RT and NT groups. Strongylus spp. were more common in NT groups but also showed unexpectedly high abundances in RT horses. Cylicocyclus nassatus, Cylicostephanus longibursatus, and Cyathostomum catinatum were more abundant in RT groups, suggesting that strongyle communities in domestic equines may have been shaped by anthelmintic treatments during last decades. The decreased classification success for reads from non-caballine equines suggests that there are more strongyle species specific for this rarely-investigated group which requires additional efforts to improve the sequence database, particularly for these hosts.

ABSTRACTOuter membrane vesicles (OMVs) are nanosized vesicles naturally secreted by Gram‐negative bacteria and represent a promising platform for vaccine development. OMVs possess inherent immunostimulatory properties due to the presence of pathogen‐associated molecular patterns (PAMPs), providing self‐adjuvanting capabilities and the ability to elicit both innate and adaptive immune responses. This review outlines the advantages of OMVs over traditional vaccine strategies, including their safety, modularity, and the potential for genetic engineering to enable targeted antigen delivery. We describe approaches to enhance OMVs yield and immunogenicity, such as modifications to reduce lipopolysaccharide (LPS) toxicity and systems enabling antigen localization—either on the surface or within the lumen—using fusion constructs like ClyA, Lpp‐OmpA, AIDA‐I, Hbp, and Sec/Tat signal peptides. We further summarize preclinical applications of OMVs‐based vaccines targeting bacterial pathogens, viral infections, and cancer. In addition, we address key challenges in large‐scale production, purification, and long‐term stability, and explore strategies for conjugating or encapsulating heterologous antigens. Overall, OMVs offer a versatile and scalable extracellular vesicle‐based platform with strong potential for next‐generation vaccines targeting diverse infectious diseases and beyond.

ABSTRACTCameroon Blackbelly sheep are a domestic breed of hair sheep from West/Central Africa. They are popular with small‐holder farmers in Cameroon as they are highly resilient to local environmental challenges and are prolific a‐seasonal breeders. The aim of this study was to characterise the genetics of Cameroon Blackbelly sheep in relation to global sheep populations and to investigate their relationship to Caribbean hair sheep. We first examined the genetic diversity of the Cameroon Blackbelly breed relative to global sheep populations using 50K SNP data. We also used whole genome sequence data to further investigate relationships between Cameroon Blackbelly and breeds from Africa and Europe, as well as the Barbados Blackbelly breed from the Caribbean, which is phenotypically similar to Cameroon Blackbelly. ADMIXTURE results based on 50K and WGS data demonstrated both West/Central African and European ancestries for the Barbados Blackbelly sheep. Results from f4‐statistics‐based qpAdm analyses supported these findings. Local ancestry inference identified several genomic regions in Barbados Blackbelly with high proportions of West/Central African ancestry. One of these, on OAR3, includes various keratin genes, suggesting that these genes may play a role in the shared coat phenotypes of the Barbados Blackbelly and Cameroon Blackbelly. This result is consistent with previous reports of adaptive introgression of coat characteristics in both wild and domesticated species. The findings of our study support the view that sheep were transported from West/Central Africa to the Caribbean as part of the transatlantic slave trade and European colonisation, similar to introductions proposed for cattle and goats.

Abstract Swine infections withActinobacillus pleuropneumoniae(App), the causative agent of porcine pleuropneumonia, lead to significant production losses. Surviving pigs may harbor antibiotic-resistant bacteria, highlighting the need for alternatives to reduce antimicrobial use. Stimulation of respiratory innate immunity via Toll-like receptor 5 (TLR5) agonists such as FLAMOD (a recombinant flagellin), has emerged as a promising strategy for combating bacterial lung infections. In a recent study, aerosolized administration of FLAMOD was found to elicit respiratory immune responses in pigs. This study assessed FLAMOD’s protective effects againstApp, either as a prophylactic intervention or as an adjunct to antibiotic therapy. Prophylactic administration of aerosolized FLAMOD via nebulization beforeAppchallenge failed to confer protection. However, in a therapeutic setting, where pigs were infected withAppand treated with either a subtherapeutic dose of penicillin G (PenG) alone or a combination of PenG and aerosolized FLAMOD. Notably, the FLAMOD and PenG combination significantly improved bacterial clearance from the lungs. Moreover, FLAMOD-PenG treated pigs exhibited a trend toward increased weight gain and fewer lung lesions compared to those receiving PenG alone. These findings provide proof for the concept that FLAMOD enhances antibiotic efficacy, potentially lowering the required antibiotic dose and contributing to antimicrobial resistance mitigation in pigs.

La spectrométrie portable et miniaturisée (proche et moyen infrarouge, Raman), couplée à des modèles chimiométriques performants, offre des potentialités pour la détection sélective de polluants agricoles et la caractérisation des acides gras en aquaculture et aviculture, avec des mesures rapides, fiables et applicables à la sélection génétique et à l’agro-industrie.

BackgroundBisphenol S (BPS) is the main substitute for bisphenol A (BPA), a well-known plasticiser and endocrine disruptor. BPS disrupts ovarian function in several species. Moreover, a few studies have reported that the effects of BPS might be modulated by the metabolic status, and none have characterised the granulosa cell (GC) proteome after chronic BPS exposure.ObjectivesThis study aimed to decipher the mechanisms of action of chronic BPS exposure on the proteome of ewe GCs while considering the interaction between a deliberate contrasted metabolism and reproductive function.MethodsForty ewes were split into two groups with contrasted diets: restricted (R, n = 20) and well-fed (WF, n = 20). The R and WF ewes were subdivided according to the dose of BPS administered through the diet (0–50 µg/kg/day), forming four groups: R0, R50, WF0 and WF50. After 3-month BPS daily exposure, GCs were recovered during the pre-ovulatory stage and proteins were analysed by nano-liquid chromatography coupled with tandem mass spectrometry.ResultsChronic exposure to BPS affected the GC proteome differently according to the ewe metabolic status. Fifty-nine out of 958 quantified proteins were differentially abundant between groups and are mainly involved in carbohydrate and lipid pathways. Unsupervised hierarchical clustering of differentially abundant proteins (DAPs) identified four clusters of 34, 6, 5 and 14 proteins according to the BPS exposure and diet interaction. Pairwise comparisons between groups also revealed a strong effect of BPS exposure and diet interaction. Functional analysis of DAPs highlighted that BPS upregulated β-glucuronidase (GUSB; p = 0.002), a protein especially able to deconjugate bisphenol glucuronides (BP-g). Moreover, among unexposed ewes, GUSB was detected only in well-fed ewes.DiscussionConjugation of glucuronides inhibits the oestrogenic activity of bisphenols. Upregulation of GUSB in ewes dosed with BPS would prolong the oestrogenic effects of BPS by deconjugating BPS-g into free BPS. In addition, literature has reported an up-regulation of GUSB in people suffering from obesity. Therefore, people suffering from obesity could be subjected to prolonged and aggravated exposure to BPS. These data highlighted the deleterious effects of BPS and its interaction with metabolic status.