Effects of single and multi-strain probiotics on the growth, hemato-immunological, enzymatic activity, gut morphology and disease resistance in Rohu, Labeo rohita

Abstract The present study was aimed at evaluating the effects of Bacillus strains obtained from the mangrove environment as dietary probiotic on Rohu, Labeo rohita. Under the laboratory trial, Rohu fingerlings (average weight 5.02 ± 0.85 g) were fed with nine experimental diets containing B. amyloliquefaciens BN06 (106 cfu/ g feed as Treatment 1 (T1) and 109 cfu/ g feed as T2), B. subtilis WN07 (106 cfu/ g feed as T3 and 109 cfu/ g feed as T4), B. megaterium CT03 (106 cfu/ g feed as T5 and 109 cfu/ g feed as T6) and a mixture of all the three bacteria in equal parts (106 cfu/ g feed as T7 and 109 cfu/ g feed as T8) and control feed (C) without probiotic bacteria for 45 days. After 45 days of feeding trial, the fishes were challenged with Aeromonas hydrophila, and survival percentage was recorded for 10 days. Results revealed that weight gain and specific growth rate were significantly higher (P