Association of Novel Mutations in the Vasoactive Intestinal Peptide Receptor-1 Gene with Egg Shell Thickness in Three Strains of Laying-Type Quail

This study aimed to investigate the potential role of the vasoactive intestinal peptide receptor-1 (<i>VIPR-1</i>) gene polymorphisms and haplotypes in influencing egg production performance and egg quality parameters in laying-type quail. Genomic DNA was extracted from 150 quail across three strains: Chinese yellow (CY, <i>n</i> = 50), Beijing white (BW, <i>n</i> = 50), and Korean (KO, <i>n</i> = 50). We designed two pairs of primers and initiated PCR amplification, after which the amplified products were sent to a testing company for purification. Sanger sequencing was employed to identify single nucleotide polymorphisms (SNPs) within the <i>VIPR-1</i> gene. Two SNP sites were selected for genotyping; g.1603402T>G was analyzed using PCR-RFLP with the <i>Bsr</i>D I enzyme, while g.1614884A>G was genotyped using the <i>Hpy</i>CH4 IV enzyme. The association results revealed that the g.1603402T>G site showed significant association with egg shell thickness (EST) in the BW strain (<i>p</i> < 0.05). There were no significant associations between these two loci and the remaining egg quality traits in the BW and KO strains (<i>p</i> > 0.05). Differences in egg quality and laying performance among haplotype combinations were not significant (<i>p</i> > 0.05). In conclusion, the <i>VIPR-1</i> gene, with its identified polymorphisms and haplotypes, has potential as a molecular marker that could improve egg shell thickness in BW quail.