Host genetic and environmental determinants of chicken gut microbiota: A review

The gut microbiota is a diverse and abundant microbial community in animals; it plays a key role in nutrient absorption and immune defense and is an important factor affecting chicken health and growth performance. Understanding the composition of chicken gut microbiota and its influencing factors can provide a theoretical foundation for maintaining the diversity and microecological balance of beneficial microbial communities in the chicken intestinal tract. This review aimed to explore the recent advancements in understanding the non-genetic e.g. environmental and host genetic factors that influence the chicken gut microbiome, focusing on the gut microbial composition including host genetic kinship, heritability, microbial quantitative loci, and candidate genes. Studies on host genetic factors have identified several genes associated with gut microbial composition including lipid droplet associated hydrolase (LDAH) and apolipoprotein B (APOB) associated with Staphylococcus; TOX high mobility group box family member 2 (TOX2) significant locus linked to Veillonella, and reelin (RELN), lumican (LUM), and S-phase cyclin A associated protein in the ER (SCAPER) associated with intestinal microbial abundance. These factors are involved in host growth, development, and immune system regulation, collectively indicating that host genes play a significant role in regulating chicken gut microbiota. Furthermore, a comprehensive exploration of both non-genetic and host genetic factors could provide a solid foundation and practical strategies for improving chicken health and production performance by regulating the gut microbiota.