Effects of breed, sex and diet and their interactions on fat deposition and partitioning among depots of broiler chickens

The effects of breed (Hubbard and Anak), sex and diet (two levels of protein (high or low) with two levels of crude fiber (low or high) at each level of protein) on fat yields and partitioning among the depots were studied. No significant differences were found between breeds in fat yields and in fat partitioning among the major fat depots. Expressed as a percentage of live body weight, females had a greater percentage of non-carcass fat, carcass fat and total body fat than males. Females tended to partition more of their fat to non-carcass fat, whereas males tended to partition more of their fat to carcass fat. The effects of diet were consistent over the breeds and for all fatness traits. Non-carcass fat, carcass fat and total body fat yields were greatly depressed and favorable fat partition between depots was achieved through feeding birds high protein- high fiber diets. These birds tended to partition more of their fat to carcass fat depots (more valuables) and less to non-carcass fat depots. Breed x sex, breed x diet and sex x diet interactions did not significantly influence most of fatness traits indicating that the factors under consideration act independently of each other. Significant sex x diet interactions was found for carcass fat and total body fat relative to live body weight: the sexual dimorphism in low protein diet is more pronounced than in high protein diets. The differences between sexes in their response to diet for these traits might have important implications.