Dynamic changes in insulin-like growth factor binding protein expression occur between embryonic and early post-hatch development in broiler chickens.

Somatotropic gene expression has been altered by genetic selection, and developmental changes in insulin-like growth factor (IGF) and IGF binding protein (IGFBP) expression may contribute to rapid growth and muscle accretion in commercial broilers. The objective of this study was to evaluate changes in somatotropic axis activity between embryonic day (e) 12 and post-hatch day (d) 21. Liver and breast muscle (pectoralis major) were collected to measure gene expression, and blood was collected post-hatch to measure circulating IGFs.

The Effect of Commercial Genetic Selection on Somatotropic Gene Expression in Broilers: A Potential Role for Insulin-Like Growth Factor Binding Proteins in Regulating Broiler Growth and Body Composition.

The somatotropic axis influences growth and metabolism, and many of its effects are a result of insulin-like growth factor (IGF) signaling modulated by IGF-binding proteins (IGFBPs). Modern commercial meat-type (broiler) chickens exhibit rapid and efficient growth and muscle accretion resulting from decades of commercial genetic selection, and it is not known how alterations in the IGF system has contributed to these improvements. To determine the effect of commercial genetic selection on somatotropic axis activity, two experiments were conducted comparing legacy Athens Canadian Random Bred and modern Ross 308 male broiler lines, one between embryonic days 10 and 18 and the second between post-hatch days 10 and 40.