Growth Promoting Potential and Colonization Ability of Probiotics (Bacillus coagulans and Bacillus subtilis) on the Freshwater Prawn Macrobrachium rosenbergii Post-Larvae

Abstract

The probiotic effects of Bacillus coagulans and Bacillus subtilis were studied on survival, growth, concentrations of basic biochemical constituents, activities of digestive enzymes, and their colony establishments in the gut of Macrobrachium rosenbergii post-larvae (PL). Eleven groups of PL (2.03±0.05 in length and 0.18±0.01g in weight), each consists of 35 individuals maintained in 25 L of ground water and fed ad libitum with five serially diluted concentrations, 10-1, 10-3, 10-5, 10-7 and 10-9 of B. coagulans, and B. subtilis incorporated diets containing 40% protein, for 45 days. Diet without incorporation of any of these probiotics was served as control. These probiotics were found to be alive in the respective feed even on day-15 after their formulations. Significant improvement in survival, nutritional indices (weight gain, specific growth rate, food conversion ratio and protein efficiency ratio), contents of basic biochemical constituents (total protein, amino acid, carbohydrate and lipid) and activities of digestive enzymes (protease, amylase and lipase) were observed (P<0.05), particularly in 10-7 concentration of B. coagulans, and B. subtilis incorporated diets fed PL when compared with control. The biochemical confirmation tests revealed that presence of Escherichia coli, Acetonobacter sp., Salmonella sp., and Pseudomonas sp., in the gut of control PL. In the gut of PL fed with B. coagulans incorporated diet, Acetonobacter sp., Salmonella sp., and Pseudomonas sp., were found to be competitively excluded, whereas, in the gut of PL fed with B. subtilis incorporated diet, Acetonobacter sp., and Salmonella sp., only were found to be excluded competitively. Actually, colonies of Bacillus sp., and Lactobacillus sp., were found to be establishment in the gut of PL fed with B. coagulans, and B. subtilis incorporated diets. Overall, these probiotics incorporated diets produced better growth and survival due to better FCR and activities of digestive enzymes, which in turn led to better nutritional profile. Therefore they are recommended as feed additives for sustainable culture of M. rosenbergii.