CORRELATION OF IGF-1 GENE EXPRESSION AND CARCASS CHARACTERISTICS IN HEAT-STRESSED SAGA, SASSO, AND COBB 500 CHICKENS

Abstract

This study investigated the correlation between Insulin-like Growth Factor 1 (IGF-1) gene expression and carcass characteristics in three commercial chicken breeds (SAGA, Sasso, and COBB 500) exposed to heat stress (HS) (34 °C) in a controlled environment from two weeks of age to four weeks. Birds were subjected to controlled heat stress, and IGF-1 gene expression in breast muscle (Pectoralis major) was measured using qPCR. Carcass weights, including breast muscle, drumstick, thigh, shank, and wing weights, were assessed. qPCR was performed, and the Ct values were collected and correlated with relative carcass weight values. Results revealed varying relationships between IGF-1 expression and carcass traits within and across breeds. In SAGA chickens, IGF-1 showed a weak positive correlation with carcass weight (r = 0.26) and a moderate negative correlation with breast muscle weight (r = 0.48); other traits showed weak correlations. Sasso chickens exhibited a weak negative correlation with carcass weight (r = -0.116) and weak positive correlations with other traits. Conversely, COBB 500 chickens demonstrated strong negative correlations between IGF-1 and carcass weight (r = -0.74), breast muscle weight (r = -0.60), and other carcass traits, suggesting a negative impact of IGF-1 expression on carcass traits under heat stress. The differing patterns in SAGA and Sasso chickens compared to COBB 500, emphasized the role of genetic background in HS responses. These insights enhance the understanding of heat tolerance mechanisms and can guide targeted breeding strategies for better poultry production in HS conditions.