Isolation, estimation of bacterial load, and characterization of gut microbes of three Garra species from Bhavani river, Western ghats,Tamil Nadu, India

Abstract

Microbiomes play an important role in fish physiology, particularly in digestion, by metabolizing largely indigestible feed components for the host or synthesis of essential micronutrients. The gut flora has a dynamic effect on the host’s gut and systemic immunity. This study is the preliminary exploration of gut microflora of three species Garra mcclellandi, Garra stenorhynchus, and Garra gotyla stenorhynchus . The total bacterial load ranges from 66×108 CFU/g to 81×108 CFU/g in the gut sample. It was found that the maximum load in G. stenorhynchus with 81×108 CFU/g followed by Gg. stenorhynchus with 72×108 CFU/ml minimum in G. mcclellandi with 66×108 CFU/ml. The isolates were subjected to various biochemical characterizations such as the Indole test, Voges Proskauer test, Methyl Red test, Carbohydrate Utilization Test, Citrate Utilization Test, Starch Hydrolysis, and Catalase Production activity. The three fish gut samples are screened for antagonistic properties for certain human pathogens which show zero antagonistic activities. The present preliminary study shows variation in the gut microflora and these microbes may be used for the development of probiotics and drug production.