author(s)
Anita, SI Yusufzai, AK Jha, RA Khilleri and AY Desai

abstract
Genetically improved farmed tilapia (Oreochromis niloticus) is the food fish of 21^st century; it can grow in marine as well as freshwater environments and omnivorous fish. The culture practice of tilapia is providing nutritional and income security to small scale farmers all over the world. Current study was designed to isolate lactobacillus species from gastrointestinal tract of GIFT tilapia (O. niloticus) as potential probiotic. The whole gut of GIFT tilapia fingerlings was taken for the study on MRS agar. Three colonies were isolated on the basis of colony morphology similar to lactobacillus which was further conformed by biochemical test like catalase negative and endospore forming bacteria were identified as lactobacillus species. For probiotic potential enzymatic activity index was measured for two selected colonies C: 2 showed the lipase activity 7mm; while C: 5.6mm. For protease activity C: 2 and C: 3 showed 8 and 7.5mm respectively. Both the colonies were amylase negative. The findings of the study indicate that the gastrointestinal tract of GIFT tilapia (O. niloticus) contains lactobacillus species, which helps in utilization of feed protein and lipids.