Evaluation Of Growth Performance And Muscle Marker Genes Expression In Four Different Broiler Strains In Jordan

This study investigates the expression of the muscle growth factors Myostatin (MSTN) and Insulin-like growth hormone type I (IGF-I) and muscle marker genes MyoD and MyoG in relation to growth performance and meat characteristics in four different commercial broiler strains. Eight hundred, one-day-old chicks of Hubbard Classic (HC), Cobb500 (Cobb), Ross308 (Ross) and Indian River (IR) strains were randomly distributed in a completely randomised design into four groups for 28 days. At the end of the growth trial, 10 birds from each strain were weighed and slaughtered. A sample of Pectoral muscle was taken and kept in RNA solution for mRNA expression level measurements. Gene expression in the pectoral muscle at 20 days revealed that MSTN expression was higher for Ross than HC and IR. IGF-I expression was highest in IR and lowest in HC. MyoD expression was lowest in HC but higher in Ross and Cobb, while MyoG expression was similar. At the end of the experiment, IR gained the highest (p < .0001) body weight, while Ross the lowest, yet still with no significant differences in body weight gain among the four strains. HC scored the lowest (p = .01) efficiency in feed consumption (1.60 +/- 0.03 kg/kg). Hot and cold carcase weights of IR were significantly heavier (p < .0001) than the other strains, with no significant difference in dressing percentages. Cooking loss was the highest (p = .058) for Cobb, IR, HC, and Ross, in decreasing order. The meat-tenderness value was highest for Ross, while differences in pH, colour and water holding capacities were insignificant among the strains.