Effect of protease on production performance, carcass characteristics and immune response of broilers

The present study was conducted at Poultry Research Center, University of Agriculture, Faisalabad, to estimate the result of different inclusion levels of protease on production performance, carcass characteristics and immune response of broilers. One hundred and twenty, day old broiler chicks were obtained from a local hatchery. The experimental chicks were divided into 4 Treatment groups i.e., A, B, C and D. Each Treatment comprised of 30 chicks with three replicates (10 chicks each). Birds were offered commercial broiler starter and finisher feed for 1-3, 4-5 weeks, respectively. Treatment A birds were fed without protease supplementation and were served as control. Treatment sets B, C and D were given protease @ 0.55 g, 0.73 g and 0.92 g per ton of feed, respectively. Birds were raised under uniform management conditions. Data were collected for initial b6dy weight, weekly body weight, weekly feed consumption and mortality (if any). FCR was calculated from the data regarding feed intake and body weight gain. At the end of the experimental trial, 3 birds from each replicate was picked informally, weighed and slaughtered to record dressing percentage, and organ weight. Immune response was investigated by New Castle disease and Infectious Bursal Disease titers. Economics of the trial was calculated at the end of experiment. The data thus collected was statistically analyzed using Analysis of Variance Technique under Completely Randomized Design. Treatment means were compared by Least Significance Difference test. Feed supplementation of different inclusion levels of commercial protease during 2-5 weeks of age significantly (p less than 0.05), improved weight gain (20.01-25.01%), consumed less feed (17.55-21.28%) improved feed conversion ratio (21.2126.92%) and lowest mortality rate (0%). Slaughtered data showed that dressing percentage exhibited a significant effect by the feed supplementation of different levels of protease. Similarly a significant effect was observed on organ weight of heart, liver and, gizzard but non-significant effect was observed on spleen weight by the feed supplementation of protease. However, ND and IBD antibody titer was improved significantly (p less than 0.05) by protease supplementation at different levels as compared to control group (A). The maximum values for antibody titer against Newcastle disease and Infectious Bursal disease were recorded in Treatment B (protease @ 0.55 g/ton of feed) which was 7.33 and Treatment D (protease @ 0.92 g/ton of feed) was 94, respectively. The birds using feed protease @ 0.55 g/ton of feed fetched the highest profit (Rs. 64.53) followed (Rs. 56.17), (Rs. 44.09) and (Rs. 21.93) in B, D, C and A group respectively.