Though it is well known that insulin-like growth factor (IGF) binding protein 7 (IGFBP7) plays an important role in myogenesis and adipogenesis in mammals, its impact on the proliferation, differentiation, and lipid deposition in chicken primary myoblasts (CPM) and intramuscular preadipocytes remains unexplored. In the present study, we firstly examined the correlation between SNPs within the genomic sequence of the IGFBP7 gene and carcass and blood chemical traits in a F2 resource population by genetic association analysis, and found that a significant correlation between the SNP (4_49499525) located in the intron region of IGFBP7 and serum high-density lipoproteins (HDL). We then examined the expression patterns of IGFBP7 across different stages of proliferation and differentiation in CPMs and intramuscular preadipocytes via qPCR, and explored the biological functions of IGFBP7 through gain- and loss-of-function experiments and a range of techniques including qPCR, CCK-8, EdU, flow cytometry, Western blot, immunofluorescence, and Oil Red O staining to detect the proliferation, differentiation, and lipid deposition in CPMs and intramuscular preadipocytes. We ascertained that the expression levels of the IGFBP7 gene increased as cell differentiation progresses in CPMs and intramuscular preadipocytes, and that IGFBP7 promotes the proliferation and differentiation of these cells, as well as facilitates intracellular lipid deposition. Furthermore, we investigated the regulatory mechanism of IGFBP7 expression by using co-transfection strategy and dual-luciferase reporter assay, and discovered that the myogenic transcription factors (MRF), myoblast determination factor (MyoD) and myogenin (MyoG), along with the adipocyte-specific transcription factor (TF) CCAAT/enhancer-binding protein α (C/EBPα), can bind to the core transcription activation region of the IGFBP7 promoter located 500 bp upstream from the transcription start site, thereby promoting IGFBP7 transcription and expression. Taken together, our study underscores the role of IGFBP7 as a positive regulator for myogenesis and adipogenesis, while also elucidating the functional and transcriptional regulatory mechanisms of IGFBP7 in chicken skeletal muscle development and intramuscular adipogenesis.

This study investigated the effects of genotype, rearing system, and slaughter age on meat quality by comparing Moroccan indigenous Beldi chickens with commercial ROSS 308 broilers, with the aim of identifying strategies for optimizing nutritional properties. A total of 400 birds (200 Beldi and 200 ROSS) were reared either in intensive (10 birds/m², commercial diet) or extensive rearing systems (4 birds/m², outdoor foraging). ROSS chickens reared intensively were slaughtered at 4, 5, and 6 weeks, whereas the other experimental groups were slaughtered at 12, 18, and 24 weeks. Physico-chemical composition (dry matter, crude protein, ash , and fat content, and fatty acid (FA) profile, pH, cooking loss, color, and tenderness) were analyzed. Each experimental group included 100 birds, which were further divided into two subgroups of 50 birds each, serving as biological replicates. Data were analyzed using a mixed linear model with repeated measures on muscles. Subgroup-level analyses showed no significant differences, allowing data to be pooled for group-level comparisons. Results showed that Beldi chickens exhibited higher dry matter (28.25 vs. 25.48 %; p < 0.001) and crude protein (24.20 vs. 18.86 % FM; p < 0.001), but lower fat content (1.77 ± 0.10 % vs. 1.92 ± 0.09 % FM; p < 0.001) than ROSS chickens. Particularly in the extensive system and at later slaughter ages, Beldi chickens exhibited higher pH values across both the breast and thigh and firmer meat with higher shear force values. Under the intensive system, chicken meat was characterized by higher tenderness, lightness (L*), and yellowness (b*), but reduced redness (a*) and cooking loss, compared to the extensive system. The fatty acid (FA) profile also varied according to these factors, with meat from Beldi chickens characterized as healthier with lower SFA and MUFA content, but higher PUFA content. Moreover, according to health indices, Beldi chickens were characterized by higher PUFA/SFA, desirable fatty acids (DFA), essential fatty acids (EFA), and LA/ALA, and a lower thrombogenic index (TI) than ROSS chickens. Meat from the extensive system was characterized by higher total SFA and MUFA and lower PUFA. In summary, Beldi chickens, particularly when reared under extensive systems, produced meat with enhanced nutritional quality, whereas ROSS broilers provided more tender meat. Tailoring rearing strategies to each genotype's strengths can help optimize meat quality and meet diverse consumer preferences.

Egg production represents one of the most economically critical traits in commercial poultry production, orchestrated primarily by the hypothalamus-pituitary-ovarian (HPO) axis. Synaptotagmin 1 (SYT1), a ubiquitous component of the nervous and endocrine systems, functions as a key mediator of calcium-dependent neurotransmitter release and hormone secretion. However, the functional role of SYT1 in avian reproductive performance has remained elusive. In this study, we present evidence that single nucleotide polymorphisms (SNPs) within the SYT1 gene effectively distinguish commercial laying hens from local wild breeds, as demonstrated through principal component analysis (PCA), suggesting the gene's pivotal role in selective breeding for enhanced egg production. Through genotype-phenotype correlation analyses, we identified two SNPs, rs39497549 and rs39477032, that exhibit strong associations with egg laying performance. Furthermore, tissue-specific expression levels showed profiling analysis revealed SYT1 transcript levels in pituitary and ovarian tissues of high-producing hens relative to their low-producing counterparts, and these expression levels showed strong positive correlations with circulating concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2). In addition, fluorescence in situ hybridization analyses further confirmed spatial co-localization of SYT1 and LH within anterior pituitary cells, suggesting a direct involvement of SYT1 in gonadotroph activity. Functional validation through in cultured pituitary cells revealed that gonadotropin-releasing hormone (GnRH) agonist stimulation significantly upregulated SYT1, follicle stimulating hormone beta subunit (FSHβ), and luteinizing hormone beta subunit (LHβ) mRNA, along with enhanced secretion of FSH and LH. Conversely, SYT1 knockdown attenuated GnRH-induced expression and secretion of gonadotropins, while SYT1 overexpression potentiated these effects. Additionally, SYT1 modulated steroidogenesis in ovarian granulosa cells by regulating the expression of steroidogenic enzymes and progesterone production. Taken together, our findings establish SYT1 as a master regulator of chicken egg production performance via modulation of reproductive hormone synthesis and secretion within the HPO axis. These results position SYT1 polymorphisms as promising genetic markers for selective breeding programs in commercial laying hens improving egg production traits in indigenous chicken breeds.

Background: Traditional poultry farming plays a vital role in rural Morocco. However, management systems are informal and there is limited data on the performance of local Beldi chickens. Aim: This study aims to characterize backyard poultry farming practices and assess the zootechnical performance of Beldi chickens in two contrasting regions: Khemisset, where backyard poultry farming is widespread; and Skhirate-Temara, known for intensive commercial poultry production, which exists alongside the traditional sector. Methods: A field survey was conducted from November 2020 to March 2022, involving 320 randomly selected households (179 in Khemisset and 141 in Skhirate-Temara). Data were collected from face-toface interviews using a semi-structured questionnaire. Further data were gathered from on-farm observations and direct measurements of poultry. A total of 240 hens and 134 roosters were weighed using digital scales. In addition, 200 eggs were weighed and measured for length and width using a vernier caliper. Descriptive statistics and Chi-square tests were applied to analyze flock composition, management practices and productivity. Results: The results showed that 86% of poultry farms were managed by women, with a high illiteracy rate (76%) among farmers. Local chickens represented 84% of poultry flocks, with an average flock size of 25 birds per household. Feeding relied mainly on scavenging, supplemented with barley, stale bread and household wastes. Juvenile mortality was 64%, largely due to inadequate chick-rearing practices. Hens laid an average of 79 eggs per year, with a mean egg weight of 54.3 ± 5.4 g. Body weight averaged 1407 ± 291.9 g in hens and 1758 ± 335.2 g in roosters, with slight regional variations. Health management was poor, with 96% of farmers reporting frequent disease outbreaks. Only 5.4% of farmers had I access to veterinary practitioners. Biosecurity measures were minimal. Disease control was primarily based on traditional remedies or the use of antibiotics with no veterinary supervision. These findings highlight significant challenges for poultry production, including high mortality rates, poor housing, inadequate feeding and poor health management. Conclusions: Addressing these issues by developing management strategies to improve biosecurity and veterinary access is essential to enhance the sustainability and productivity of backyard poultry farming in Morocco.

Contexte : Le dromadaire occupe une place centrale dans le patrimoine culturel et économique des régions du Sud-Maroc, où les conditions environnementales difficiles limitent l’accès aux ressources pastorales. Objectif : cette étude, menée en mai 2022, visait à analyser le comportement alimentaire journalier des dromadaires provenant de deux systèmes d’élevage (périurbain et transhumant) rencontrés dans la province de Guelmim, au sud du Maroc. L’objectif était de comprendre comment ces animaux exploitent des ressources pastorales limitées pour satisfaire leurs besoins alimentaires. Méthodes : Quinze femelles de cinq troupeaux distincts ont été suivies quotidiennement. Les données ont été collectées depuis la sortie des animaux jusqu’à leur retour à l’enclos, en suivant leurs activités journalières (pâturage, déplacement, repos, abreuvement) et les quantités alimentaires ingérées ont été estimées par la méthode des coups de dents. Résultats : Le pâturage représentait l’activité principale (54,3 % du temps de séjour), suivi par le déplacement (32,6 %), le repos (12,2 %) et l’abreuvement (0,9 %). Malgré les conditions arides, les dromadaires maintiennent une alimentation diversifiée grâce à leur comportement ambulatoire, broutant jusqu’à 82 % des espèces disponibles sur les parcours, soit 19 espèces sur 23, principalement des plantes vivaces spontanées. Les quantités ingérées variaient de 8,3 à 12,3 kg de matière sèche (MS) par jour selon l’élevage, avec des petites bouchées allant de 0,5 à 3,9 g de MS de différentes espèces, à une cadence de 0,3 à 7 bouchées par minute. Conclusions : Les dromadaires adaptent leur comportement alimentaire en fonction de leur environnement, préservant ainsi leur milieu tout en répondant à leurs besoins nutritionnels, quelles que soient les pratiques d’élevage auxquelles ils sont soumis.