HSP70 gene polymorphism and association with growth performance and corticosterone in crossbred native chickens

Abstract

This study evaluated heat shock protein 70 polymorphism and its association with growth perfor-mance and circulating corticosterone concentration in Chai-Aree crossbred native chickens. A total of 150 birds were genotyped using PCR-RFLP, and circulating corticosterone concentration was deter-mined by competitive ELISA. Three genotypes (CC, CG, and GG) were identified with frequencies of 0.40, 0.44, and 0.16, respectively, whereas allele frequencies of C and G were 0.62 and 0.38. Observed and expected heterozygosity were 0.44 and 0.47, respectively, indicating moderate genetic diversity. The population conformed to Hardy–Weinberg equilibrium (χ² = 0.66; p>0.05). Growth performance and corticosterone concentration were analyzed using a general linear model. HSP70 genotype had no significant effects on body weight, average daily gain, feed conversion ratio, or circulating corti-costerone concentration (p>0.05). These findings indicate that polymorphism at the HSP70 locus did not influence growth performance or systemic stress response under the experimental conditions. Alt-hough HSP70 contributes to genetic variation in crossbred native chickens, it has limited value as a standalone molecular marker. Future studies should investigate multiple candidate genes and genotype × environment interactions, particularly under heat stress conditions.