Effect of heat stress on growth and IGF-1 expression in synthetic broiler and native cross chicken

IGF-1 is a major gene that affects growth and is essential for myogenic development in chickens. This study examined growth performance, mRNA expression, and serum concentration in fast-growing IBL-80 and slow-growing native cross (NC) broilers under heat stress conditions.

Poultry birds from each genetic cohort were categorized into control (mean THI: 22.45 ± 0.37) and heat stress (mean THI: 32.87 ± 0.46) groups. Both genetic groups' body weights and cloacal temperatures were recorded on days 21 and 42. Blood was drawn on days 21 and 42. Cloning, expression analysis were used to examine IGF-1's growth role.

Heat stress markedly affected the growth performance and cloacal temperatures of both genetic groups. The downregulation of IGF-1 mRNA expression was apparent in birds subjected to heat stress on days 21 and 42 across both genotypes. Both rapidly growing synthetic broilers and slowly growing native cross chickens exhibited lower levels of IGF-1 in serum samples.

This study found that heat stress affected bird growth, gene expression, and serum IGF-1 levels regardless of genotype. Slow-growing native cross chickens lost less weight and expressed less IGF-1 under heat stress than fast-growing synthetic IBL-80 broilers.