The Use of G Biotic Microorganism supplements in Tilapia Feeds on Growth Performance and Immunity

Abstract

The use of G biotic Bacillus subtilis for Nile tilapia was conducted to examine its effects on the growth performances and immunity. 480 (initial average weight of 18.41 grams) tilapia were randomly distributed into (9 m3) cages located in an earthen pond with the density of 4.4 fish/m3; total 12 cages. The 1×107 CFU/g of Bacillus subtilis with the concentration of 0, 2, 5 and 10 ml/kg. They were laid out incompletely randomized design with 3 replications. Fish were fed experimental diets at a rate of 3% biomass per day for 60 days. The results showed probiotic supplementary diet group had slightly affected on weight gain final weight and the specific growth rate (P> 0.05). The concentration of 2 ml/kgwas the best treatment in increasing final weight, specific growth rate and feed conversion ratio (P>0.05). Survival rate was not significantly different (P> 0.05). The results of probiotics on immune system were evaluated after 20, 40 and 60 days of feeding experimental diets. Phagocytosis and Serum lysozymeactivity enhanced significantly (P<0.05). NBT values after 60 days increased significantly in fish fed 2 ml/kg when compared with other groups (P < 0.05). It was recommended that this G biotic with the concentration 2 ml/kg supplementation can be used as an alternative method for growth performances and immunity improvement in Nile tilapia.