Light exposure during incubation can influence hatching characteristics, post-hatch growth, and physiological responses in poultry. This study aimed to evaluate the impact of pre-development exposure to different cold-colored light emitting diode (LED) lights on incubation characteristics, growth performance, stress physiology, and myogenic regulatory factors (MRFs) expression level in the slow-growing native Gerze chicken breed. Fertilized eggs were incubated under red, green, white, or dark conditions. The shortest hatch window was observed under red light (42 h), while the dark condition resulted in the longest (84 h) (p < 0.05). White light exposure reduced hatchability compared to the other groups (p < 0.05), whereas green and red lights enhanced both chick weight at hatch and egg-to-chick conversion efficiency (p < 0.001). Chicks incubated under green light exhibited superior body weight during the first four weeks (p < 0.05), but those from the red light group maintained consistently higher weights thereafter (p < 0.05). The highest serotonin levels were detected in chicks from the dark group, while the lowest were associated with green light exposure. Red light exposure was associated with the lowest corticosterone concentrations (p < 0.05). Gene expression analysis revealed no significant differences in MRFs across groups. In conclusion, the spectral level of light during incubation exerts measurable effects on hatch dynamics, post-hatch growth, and hormonal regulation in Gerze chicken.

Breeding farm animals, especially poultry, helps meet global meat demand and boosts meat production efficiency. To meet high-quality meat demand, muscle growth and development must improve. Fetal skeletal muscle formation involves myogenesis, fibrogenesis, and adipogenesis. Kinase-encoding genes and myogenic regulatory factor genes regulate a complex network of intrinsic and extrinsic components in two or three stages. MYF5, MYOD, myogenin, and MRF4 are helix-loop-helix transcription factors that govern skeletal muscle cell specification and differentiation throughout embryogenesis and postnatal myogenesis. The transcription factors MYF5, MYOD, Myogenin, and MRF4 have been discovered to determine the skeletal muscle lineage and regulate myogenic differentiation during development. These factors also determine the muscle satellite cell lineage that becomes the adult skeletal muscle stem cell compartment. MYF5, MYOD, Myogenin, and MRF4 serve small functions in adult muscle, but they again direct satellite cell activity to regenerate skeletal muscle, linking genetic regulation of development and regeneration myogenesis. Understanding and identifying these genes helps increase meat yield and quality. This detailed review examines myogenic regulatory variables in satellite cell specification, maturation, and skeletal muscle regeneration.

The chicken genome is a living archive, preserving the history of ancient viral encounters within its DNA. Among these genetic relics, the Avian Leukosis Virus Endogenous (ALVE) family of LTR (Long Terminal Repeats) retrotransposons stands out not as a mere fossil, but as a dynamic and influential force in modern poultry science. While often silent, these endogenous retroviruses can awaken, casting a long shadow over poultry health and profitability. This comprehensive narrative review delves into the complex duality of ALVE elements, synthesizing recent evidence that reveals their staggering diversity, with over a thousand unique insertion sites now identified across global chicken populations. We explore the multifaceted mechanisms-from insertional mutagenesis to viral protein interference and immunosuppression-by which these elements exert their effects. This review critically appraises their tangible economic toll, detailing associations with detrimental impacts on vital production traits such as egg laying and growth, while also considering the paradoxical role of endogenous retroviruses as potential contributors to genetic diversity. Finally, we confront the pressing challenges posed by novel ALVE insertions and viral recombination events, arguing that the path to sustainable, resilient poultry production lies in harnessing advanced genomics and innovative breeding strategies to navigate this intricate endogenous retroviral landscape.

Antimicrobial resistance linked to the long-term use of antibiotic growth promoters (AGPs) in poultry has intensified the search for effective, microbiome-based alternatives that can sustain performance without compromising food safety or animal welfare. This article aims to evaluate how recent advances in p-biotics (pre-, pro-, post-, and synbiotics) are shaping the future of sustainable poultry production. To achieve this, a systematic review was conducted using studies published between 2020 and 2025 on broilers and layers from literature databases such as Web of Science, Scopus, Google Scholar, and ScienceDirect. The PRISMA method was adopted, where 39 articles met the criteria for this review article after several exclusion criteria. The review shows that p-biotics consistently modulate gut microbiota, reinforce intestinal integrity, and enhance immune competence. Notably, the data reveal a consistent 10% to 15% improvement in feed conversion ratios and body weight gain under optimized probiotic and synbiotic regimens, directly addressing the production drops typically seen after antibiotic withdrawal. Probiotics and synbiotics, particularly Bacillus and Lactobacillus based formulations and oligosaccharide containing combinations, promote beneficial microbial populations, suppress enteric pathogens, and, in several studies, improve meat or egg quality and reduce dependence on AGPs. Postbiotic preparations from inactivated bacterial and yeast sources deliver comparable health and performance benefits while lowering the risk associated with live cultures. Evidence also indicates that p-biotics can lessen environmental burden by improving nutrient utilization and reducing nitrogen and phosphorus excretion, aligning poultry systems with broader sustainability targets. Nonetheless, considerable heterogeneity in strains, dosages, delivery routes, and experimental designs limits cross study comparability and hinders the development of standardized, context specific recommendations. Moving forward, research priorities must focus on conducting strain-specific field trials to validate efficacy across different poultry types, establishing standardized dosage protocols optimized for distinct commercial feeding phases (starter, grower, and finisher), and investigating the stability and viability of these p-biotics during high-temperature feed pelleting processes.

Interest in non-antibiotic growth enhancers like probiotics has increased due to the global demand for sustainable livestock production. In order to synthesize empirical data and guide more sustainable and effective cattle feeding practices, this study systematically examines how well probiotic supplements enhance nutrient utilization and growth performance in cattle. Following PRISMA guidelines, a systematic review and meta-analysis were carried out. There were 14 peer-reviewed randomized controlled trials with 19 comparisons between different probiotic strains and cattle breeds. Key nutrient digestibility parameters were extracted, including dry matter digestibility (DMD), organic matter digestibility (OMD), crude protein (CP) digestibility, and neutral detergent fiber (NDF) digestibility. Growth performance metrics, such as average daily gain (ADG), feed efficiency (FE), body weight gain (BWG), and dry matter intake (DMI), were also extracted. Heterogeneity was evaluated and pooled mean differences were computed using Review Manager (RevMan 5.4) software. Probiotic supplementation considerably increased CP digestibility (MD=+2.72%, P=0.004) and ADG (MD = +0.04 kg/day, P

The non-random connection of alleles at various loci is known as linkage disequilibrium (LD). Combinations of alleles inside haplotypes occur at frequencies that differ from those expected on independence when two alleles at two distinct loci are in LD. When genetic variation at a locus is linked to a trait, it means that either the genetic variation at that locus directly impacts the phenotype of interest or the locus is in LD with the causal mutation. The level of LD, which dictates how many markers should be typed in a genome scan to discover a quantitative trait locus (QTL) using LD, is critical to the practicality of association studies. This review explores the origin of LD in genetics and how it applies to animal breeding and genetics.