Effect of protease on production performance, weights and proportions of primal cuts and weights of edible byproducts of broilers

Abstract

This study analyses the effect of different levels of dietary protease supplementation on the weights and proportions of primal cuts (breast, drumsticks, thighs, wings, back, pelvis) and weights of edible by-products (liver, heart, gizzard) in two strains of broilers (fast-growing Cobb 500 and medium-growing Master Gris) in a 49-day experiment. Broilers were allocated to 3 dietary treatment groups: group C (standard diet, 0% protease), group E-I (0.2% protease, crude protein level reduced by 4% compared to C) and group E-II (0.3% protease, 6% reduction in crude protein compared to C). The analysis of production performance showed lower body weights at the end of the fattening experiment, lower feed consumption and poorer feed conversion ratios in Master Gris broilers than in Cobb 500 chickens (P<0.05). As determined from data obtained at slaughter, the two broiler strains differed significantly in the weights and proportions of all primal cuts, except the proportion of back, as well as in the weights of all edible by-products, except gizzard. Dietary treatments had a significant effect (P<0.05) only on body weight and liver weight in Cobb 500 broilers belonging to E-II compared to C chickens.