Isolation and characterization of autochthonous probiotics from skin mucus and their in vivo validation with dietary probiotic bacteria on growth performance and immunity of Labeo calbasu (Hamilton, 1822).

Abstract

The present study was performed to isolate and identify antimicrobial bacteria from the skin mucus of Labeo calbasu and assess their effects as water additives alone and in synergism, with dietary probiotic bacteria Aneurinibacillus aneurinilyticus LC1 isolated from intestinal tracts of L. calbasu on physiology and survival of same fish. Eight treatments (T1-T8) were conducted in triplicate, containing 10 fishes (2.02 ± 0.01g) in each treatment: T1, control group (diet without probiotics); T2-T4, a diet with water additive probiotics; Bacillus cereus LC1, B. albus LC7, and B. cereus LC10, respectively, at 1000CFUml-1; T5, a diet with dietary probiotic A. aneurinilyticus at 3000CFUg-1, T6-T8, a diet with water additives Bacillus cereus LC1, B. albus LC7, and B. cereus LC10 at 1000CFUml-1 along with dietary probiotic A. aneurinilyticus at 3000CFUg-1. Results revealed improved growth, nutritive physiology, immune response, water quality, and survival in fish of group T8 (fingerlings fed on a probiotic diet at 3000CFUg-1 and reared in holding water treated with skin mucus bacteria B. cereus LC10 at 1000CFUg-1) as compared to other treatments, suggesting autochthonous intestinal and cutaneous mucosal bacteria as robust candidates for their collective application in aquaculture.