Physiological response of Nigerian locally adapted chickens with different heat shock protein 70 genotypes to acute heat stress

Slow growth rate and acute heat stress are among the major constraints to indigenous chicken production in Nigeria. Characterization of heat-tolerance genes is a requisite for selective breeding of poultry for improved heat-tolerance and productivity. Therefore, this study investigated variation in HSP70 gene and its association with heat-tolerance traits of Nigerian locally adapted chickens. One-day old chicks comprising 118 Yoruba Ecotype Chicken-YEC and 138 FUNAAlpha Chicken-FAC were tagged and fed ad-libitum on starter (0-6 weeks) and grower (7-24 weeks) diets. At week 12, blood was sampled, DNA was extracted, amplified and electrophoresed following standard procedures. HSP70 gene was genotyped using MmeI restriction endonuclease. At week 23, 36 chickens (six chickens per identified HSP70 genotypes) selected from each of YEC and FAC were exposed to 40?1?C for one hour. Cloaca temperature, respiratory rate (RR) and pulse rate (PR) were recorded and heat stress index (HSI) calculated. Data were analysed using descriptive statistics and ANOVA. Alleles A and B with genotypes: AA, AB, and BB were detected. After acute heat-stress, YEC with BB had higher RR value compared to those with AA and AB. The PR value of FAC with genotype BB was significantly higher (p