Exogenous protease supplementation of poultry by-product meal-based diets for broilers: Effects on growth, carcass characteristics and nutrient digestibility.

Abstract

An experiment was conducted to investigate the effects of three levels (0%, 3% and 6%) of poultry by-product meal (PBM) with or without protease on broiler growth, carcass characteristics and nutrient digestibility from 1 to 35days. Two hundred and forty birds (n=240) were fed equi-caloric and equi-nitrogenous (ME 2850kcal/kg; CP 20%) diets throughout the experiment. The enzyme supplementation increased feed intake (p<.01) and body weight gain (p<.01), but feed:gain remained unaffected (p>.05) from 1 to 21days. Increasing level of PBM decreased feed intake (p<.05), but body weight gain was improved (p<.05) at 3% PBM level during 1 to 21 days. The feed:gain was improved (p<.05) in birds fed diets containing 3% PBM. The feed:gain was also improved in birds fed diets containing 3% PBM from 1 to 35days. However, feed intake and body weight gain in birds fed diets containing PBM remained unaffected. An interaction (p<.01) on feed intake between enzyme and PBM was noticed during 1 to 21 days. However, no interaction was recorded for body weight gain and feed:gain. The per cent carcass yield improved (p<.01) in birds fed diets supplemented with enzyme. The per cent breast meat yield was depressed (p<.005) in birds fed diets containing PBM. Apparent metabolizable energy (p<.001), nitrogen retention (p<.01), apparent metabolizable energy corrected for nitrogen (p<.001), and apparent digestibility coefficient for nitrogen (p<.01) improved in birds fed diets containing enzyme; however, a reverse was noticed in those fed diets containing only PBM. In conclusion, inclusion of 3% PBM along with supplementation of exogenous protease improved performance and nutrient digestibility in broilers.