Improvement of growth, nutrient utilization and haemato‐immunological parameters in rohu, Labeo rohita (Hamilton) using Bacillus tequilensis (KF623287) through diets or as water additive

Abstract

The study appraised effects of Bacillus tequilensis (KF623287), through diets or water, on the growth and health status of rohu, Labeo rohita fingerlings. A basal diet (35% protein) was fed to the control (without B. tequilensis supplementation) and other experimental groups in triplicate for 60 days. B. tequilensis was added either to the diets at 1 × 107 cfu/g (D1), 1 × 109 cfu/g (D2) and 1 × 1011 cfu/g (D3) or to the rearing water at 1 × 107 cfu/ml (WA1), 1 × 109 cfu/ml (WA2) and 1 × 1011 cfu/ml (WA3) every 2 days. Results indicated that group D2 had significantly (p < .05) higher weight gain (115 ± 3.25%) and improved feed utilization than other experimental groups. However, group WA3 (109 ± 3.16% weight gain) appeared as the second best after D2 group. Further, improved haematological parameters, serum lysozyme, peroxidase and superoxide anion production along with increased phagocytic and respiratory burst activities were noticed in fish that received B. tequilensis either through diets (D2) or as water additive (WA3). Increased serum IgM was noticed at day 30, while decreased thereafter. The study revealed that B. tequilensis, either through diets or as water, could improve growth, nutrient utilization and immunity in L. rohita fingerlings. However dietary administration of probiotics at a lower dose was more effective than the water additive.