Abstract
Yuexi frizzled chicken has unique disease resistance and growth performance. Cholesterol 25-hydroxylase (CH25H) and its enzymatic product 25-hydroxycholesterol (25-HC) are recognized as key modulators of inflammatory signaling, immune defense, and viral restriction. However, despite its well-characterized antiviral roles in mammals, the genetic variation of CH25H and its association with growth and development traits in poultry, especially in local breeds like the Yuexi frizzled chicken, remain largely unexplored. In this study, 267 Yuexi frizzled chickens were selected as experimental materials, designed primers in accordance with the chicken CH25H gene sequence, and detected the SNPs of this gene through PCR product sequencing. As a result, we found a total of 9 SNPs, among which 4 SNPs of rs312669481 A > T, rs313861973 T > C, rs16550966 G > A, rs315898607 T > A were located in the promoter region; another 4 SNPs of rs313066955 A > G, rs312277078 G > T, rs317140635 C > T, rs317021440 C > T were located in the coding DNA sequences (CDS); and 1 SNPs of rs734814821 T>C was located in the 3'UTR region. Our results suggest that specific polymorphisms (rs16550966 G > A, rs313066955 A > G, rs312277078 G > T, rs317140635 C > T, rs317021440 C > T, rs315898607 T > A) and the H2H2 haplotype of the CH25H gene are significantly associated with growth traits in Yuexi frizzled chickens. The CH25H gene exhibits high expression during the early muscle developmental further supports its role in growth. These findings indicate that CH25H is proposed as a candidate gene for molecular marker-assisted selection aimed at improving growth performance in chicken breeding programs.