Effects of dietary administration of Shewanella haliotis D4, Bacillus cereus D7 and Aeromonas bivalvium D15, single or combined, on the growth, innate immunity and disease resistance of shrimp, Litopenaeus vannamei

The effects of single or combined use of dietary Shewanella haliotis D4, Bacillus cereus D7 and Aeromonas bivalvium D15, isolated from the gut of shrimp, were assessed on the growth, innate immunity and disease resistance of Pacific white shrimp (Litopenaeus vannamei). Shrimp was fed 28 days by five experimental diets - i) control diet with no probiotics, ii) three probiotic diets, i.e. feed supplemented with 107 cell g− 1 of D4 (D4 diet), D7 (D7 diet) and D15 (D15 diet), and iii) mixed diet comprising of strains D4, D7 and D15 at a ratio of 2:1:1, dosed at 107 cell g− 1. Results showed that growth of shrimp, i.e. final weight, weight gain, percent weight gain and specific growth rate, was improved after 28-days of feeding regime with probiotics compared to the control. Respond of several non-specific immune parameters of groups fed probiotics was also enhanced; i.e. diet D4 and D15 led to significant enhancement of both respiratory burst and superoxide dismutase activities than that of control. Moreover, the respiratory burst activity was also enhanced by mixed diet at the end of 28 days. All probiotic groups were able to increase acid phosphatase activity of shrimp between days 7 and 21. Moreover, the expression of prophenoloxidase and < beta>-1, 3-glucan-binding protein was significantly up regulated in shrimp fed D4 and D15 diets compared to control group, but penaeidin 3 expression up regulated significantly only with mixed diet after 28 days. The cumulative mortality of shrimp, experimentally challenged with Vibrio harveyi, was reduced in groups fed probiotics, i.e. D4 = 36.67%, D7 = 41.67%, D15 = 13.33% and mixed = 11.67%, respectively, than that of controls (43.33%) after 10 days of post-infection. Overall, the results of this study indicated the potential of using probiotics to improve growth, immunity and disease resistance of white shrimp.