Influence of low-protein and low-amino acid diets with different sources of protease on performance, carcasses and nitrogen retention of broiler chickens

Abstract

A 42-day experiment was conducted with 625 1-day-old male Hubbard chickens to evaluate the performance, carcass traits, nitrogen retention and economics of broiler chickens fed low protein and amino acid diets supplemented with different protease sources. Treatments included positive (PC) and negative (NC) controls (PC at 19.3% protein vs NC at 18.8% protein), with NC containing 7% less digestible amino acids. The other three treatment groups were based on the NC diet supplemented with 0.05% Cibenza® DP100 (CB), 0.02% Ronozyme® (RZ) or 0.02% Winzyme pro plus (WZ). Birds fed the PC, CB and WZ diets achieved the heaviest bodyweight compared with those fed the NC diet at end of the experiment. Total feed intake of birds fed the PC diet was higher (P < 0.05) than that of birds fed the NC diet. Feed conversion ratio was numerically significantly (P = 0.005) improved with all tested groups in comparison with NC throughout the experiment. European production index was similar (P > 0.05) among birds fed the PC, NC, RZ or WZ diets. All carcass parameters studied, including dressing, heart, gizzard, giblets, chest meat, thigh meat and abdominal fat percentages, were not significantly (P > 0.05) affected by feeding on the different sources of protease. Broilers fed the PC diet or diets formulated with all protease sources had higher (P < 0.05) nitrogen retention than did birds fed the NC diet. The supplementation of protease to low-protein and low-amino acid diets resulted in higher profit margin in broilers. It is concluded that supplementing exogenous protease to broiler diets containing low protein and amino acids improved the growth performance, feed utilisation, carcass traits, nitrogen retention and net returns of broiler chickens.

Growth performance and intestinal health of broilers fed a standard or low-protein diet with the addition of a protease

“…In this study, an extreme reduction (6%) of dietary protein and digestible amino acids negatively affected FCR, although, when protease was added, the growth performance results were similar to the standard diets. Rehman et al (2017) also observed a decrease in body weight of broilers fed diets with protein reduction, and it was associated to the low dietary protein and amino acid concentrations. These authors obtained better results of performance, feed utilization, carcass traits, and nitrogen retention when there was reduction of protein with protease supplementation.…”

The effects of low-protein diets and protease supplementation on broiler chickens in a hot and humid tropical environment

“…The protease used in this study was previously shown to enhance proteins, AAs and energy digestibility in broilers fed different protein levels [ 12 ]. Therefore, the observed improvements in nutrient digestibility and nutrient retention [ 15 , 17 , 22 ] in birds fed diets containing exogenous protease may have beneficial effects on body weight. This finding is in accordance with those reported by Angel et al [ 11 ] and Mahmood et al [ 10 ], where supplementation of mono-component protease improved growth performance in broilers.…”

Effect of Supplemental Protease on Growth Performance and Excreta Microbiome of Broiler Chicks

“…In previous studies, supplemental protease in the diet from 1 to 14 days had no effect on body weight gain, feed intake, and feed efficiency of chickens fed soybean-meal diets [32,33]. Cowieson et al also failed to observe, on days 7-14, a protease effect on bird body weight gain and feed intake, but protease appeared to increase the gain to feed ratio [34].…”

“…Cowieson et al also failed to observe, on days 7-14, a protease effect on bird body weight gain and feed intake, but protease appeared to increase the gain to feed ratio [34]. Interestingly, in all of these studies, a positive effect of protease on body weight gain and feed efficiency was observed after 14 days [32][33][34]. This indicates that exogenous protease efficacy can be impacted by the age of the birds.…”