Yield and carcass composition of broilers fed with diets based on the concept of crude protein or ideal protein

Abstract

Two experiments were conducted to evaluate the effect of diets formulated using the criteria of crude protein (CP) and ideal protein (IP) on the yield and carcass composition of male and female broilers. Birds of two broilers strains (Hybro G and Hybro PG) were reared from 1 to 42 days of age during the summer, with average temperatures of 26°C. A completely randomized experimental design was used in a 2 x 2 factorial arrangement, with 6 replicates and 20 birds per pen. On day 42, four birds from each experimental unit were killed and carcass yield and composition were determined. Breast yield was higher in males and females fed the IP-based diet than in birds fed the CP-based diet. Abdominal fat pad and carcass crude protein were statistically similar between the two protein criteria and between strains. Carcass amino acid levels evidenced higher levels of Met, Lys, Met+Cys and Thr in the males fed IP-based diets. No differences were seen between the two criteria for the females. Diets formulated according to IP resulted in better carcass and breast yield, both for males and females.

Predicting carcass energy content and composition in broilers using the group method of data handling-type neural networks

“…In general, about 0•7 of the rearing cost in poultry production is related to caloric needs (Skinner et al 1992). In addition to its measurement in the laboratory using wet chemistry, carcass composition of broiler chickens has been predicted by means of allometric equations, real-time ultrasonography, radioactive isotopes and specific gravity studies (Pesti & Bakalli 1997;Toledo et al 2004;Rosa et al 2007;Makkar 2008). Conventional laboratory techniques for determining carcass composition are expensive, cumbersome and time consuming.…”

“…In addition to its measurement in the laboratory using wet chemistry, carcass composition of broiler chickens has been predicted by means of allometric equations, real-time ultrasonography, radioactive isotopes and specific gravity studies (Pesti & Bakalli 1997; Toledo et al . 2004; Rosa et al . 2007; Makkar 2008).…”