Genetic and Hormonal Difference between High Growth Rate Breed (Cobb Broiler chicken) and Low Growth Rate Breed (Native Fayoumi chicken)

Abstract

The present study aimed to investigate the genetic and hormonal differences between low (Native Fayoumi) and high (Cobb Broiler) growth gate breeds of chicken. A total number of 100 one-day-old Fayoumi chicks and 100 one-day-old Cobb chicks were used. Chicks of each breed were allocated into three equal replicates. The growth parameters [body weight, Body weight gain (BWG) and Feed conversion ratio (FCR)], genetic expression of some growth-related genes (growth hormone, insulin like growth factor1, ghrelin and Myostatin gene) and plasma level of some growth-related hormones (Insulin, T3, T4 and corticosterone) were recorded. The obtained results revealed that, Cobb chicken had significantly higher (p<0.05) body weight, BWG and feed intake than Fayoumi chicken but the FCR of Fayoumi chicken was higher (p<0.05) than that of broiler chicken. Cobb recorded significantly (p<0.05) lower plasma level of corticosterone, T3 and T4 than Fayoumi chicken while Insulin is higher (p<0.05) in cobb chicken. Cobb recorded highly significant (p<0.05) values of GH, IGF1 and ghrelin Gene expression while myostatin gene expression was higher (p<0.05) in Fayoumi chicken than in Cobb. From the obtained results it could be concluded that, the observed high growth rate in cobb chicken may be attributed the difference in gene expression related growth as well as hormonal difference.