Association of Cellular Retinol-binding Protein 2 (CRBP2) Gene Polymorphism with Egg Production in Erlang Mountainous Chicken

Abstract

Cellular retinol-binding protein 2 (CRBP2), a vitamin A binding protein that is expressed specifically in small intestinal villus absorptive cells, plays a pivotal role in the vitamin A absorption, transport, and metabolism. Considering the fact that egg weight and egg quality were largely affected by the vitamin A levels in chicken, we investigated the genetic polymorphism of CRBP2 gene and the association with egg production traits among 349 Erlang Mountainous Chickens in this study. In the coding sequence (408bp) of four exons, we only detected one nucleotide substitution (c.349T>C) in the third exon, which caused amino acid change (p.117Y>H). The frequencies of three genotypes were 52.43% (TT), 42.41% (TC), and 5.16% (CC), respectively. Among the six studied traits, the age at first egg (AFE), total number of eggs with 300 age (EN), and average egg-laying interval (AEI) differed significantly among genotypes. The CC genotype would be genetically advantageous to improve egg production traits in Erlang Mountainous Chicken. The evolutionary conservation analysis revealed that the p.117Y>H site was high conservative in mammals, which potentially confirm the important biological function of this mutation. To our knowledge, this is first report to study the genetic polymorphism of CRBP2 gene and association with egg production traits in chicken.