Vithana, V.P.K.H.A.2022-10-072022-10-072016UWU/ANS/16/0027http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/9765/ans%2c16%2c0027-02092022101646.pdf?sequence=1&isAllowed=yAn experiment was conducted to investigate the effects of dietary poultry by product meal (PBM) 5% with or without protease enzyme on growth ,carcass characteristics and meat quality parameters of Arbor acre plus broilers. One hundred and twenty birds (n=120) were fed experimental diet from 21 day to 35 days, 1 to 10 days and 11 to 21 days broiler pre starter, broiler starter were fed respectively .In there poultry by product meal (5%),exogenous protease (with and without ) was undertaken using factorial arrangement under completely randomized design. The birds (n=120) were randomly divided into 12 replicates (10 birds/replicate) and 60 birds allocated for each treatment. PBM along with supplementation of 5% exogenous protease significantly improved growth performance of broilers .The body weight gain ,FI And FCR were increased [p <0.05] from 21 to 35 days by the enzyme treated diet. No significant differences in lengths of small intestine , breast weight, thigh weights. No significant differences in pH , water Holding capacity, Cooking loss. In conclusion, protease enzyme added poultry by product meal enhanced the weight gain and performance of broiler birds . Key words: Protease enzyme;carcass charateristics;PBM;broilersenAnimal Science Degree ProgrammeThesis