Seleksi bakteri proteolitik dan aplikasi enzim protease untuk meningkatkan kualitas pakan dan kinerja pertumbuhan ikan nila

Abstract

Growth performance of fish is highly influenced by the quality of feed, which is determined dominantly by the quality of feedstuff used and also by supplementation of exogenous enzymes. This study aimed to select protease producing bacteria, to optimize their existing potential in producing protease and to evaluate the effect of dietary supplementation of bacterial protease on feed quality and growth performance of nile tilapia. Ten strains were isolated from gastrointestinal tract of Clarias gariepinus and two of them were selected based on their maximum clear zone diameter on casein agar medium and the absence of pathogenic activity against the test fish. The incubation time for maximum protease production of two strains was 72 hours, and the optimum dosage of bacterial protease was 1000 ml /kg feed, which was determined based on the level of hydrolyzed protein. A feeding study was conducted using 7 treatments with 3 replicate groups of nile tilapia (average weight of 4,07 ± 0.25 g), reared under laboratory condition. Result showed that the addition of A1 and L1 bacterial protease gave a significant increase on feed comsumption, growth rate of nile tilapia, apparent digestibility of dry matter and crude protein, protein retention and efficiency in formulated feed. Fish survival was not different among the seven treatments. This result suggested that bacterial protease was effective in improving feed quality and growth performance of nile tilapia when it was added to formulated feed containing poorly digestible feedstuffs.