Age-related carcass composition changes in male broiler chickens

Abstract

To quantify growth and development of the broiler chicken to 70 d, a flock of male birds was sampled at regular intervals, and observations were made on growth and development of various carcass components. Birds were fed conventional diets and maintained on litter-floor pens in a room with environmental control. At 21, 28, 35, 39, 43, 47, 50, 55, 60 and 70 d of age, 12 birds were selected at random for estimation of live weight, eviscerated weight, cut-up portion composition and deboned meat yield. Observations involved weights of the various carcass components and proximate analysis. Birds showed linear growth to 70 d (P < 0.01), while development shown by the eviscerated carcass was positively quadratic (P < 0.01). Proportional fat content of the eviscerated carcass increased over time (P < 0.01), while protein content decreased (P < 0.01). The leg-thigh portion yielded the greatest quantity of meat, while the bone portion increased from 130 g to 843 g over the 21- to 70-d period. Total carcass skin increased in weight from 50 g to 365 g over the same period. Both deboned breast meat and leg meat increased quadratically over time (P < 0.01). Comparison of results with that developed 10–15 yr ago indicates chronological changes in carcass development. An apparent sporadic increase in yield of breast and thigh meat, which has also been shown by other workers, warrants further investigation. Key words: Broiler, carcass composition, meat yield