The influence of lactic acid bacteria and metabolites on intestinal microflora and nonspecific immunity of juvenile sea cucumber (Apostichopus japonicus)

A 60-day feeding experiment was conducted to evaluate the effects of lactic acid bacteria and its metabolites on bacteria of intestine,nonspecific immunity and growth of juvenile sea cucumber with initial body weight of(2.74 ± 0.17) g.Lactic acid bacteria and metabolites were added in the basal diet with 2 mL/m3(translated by farming water).Compared with control group,the lactic acid bacteria and metabolites added to the feed significantly reduced the number of intestinal Vibrio and E.coli(P0.05).The diet containing lactic acid bacteria and metabolites can increase the activities of acid phosphatase,alkaline phosphatase,and lysozyme significantly.There was no significant difference in activities of immune enzyme between the experimental groups.The results showed that the specific growth rate(RSG) of sea cucumber in the experimental groups were significantly higher(P0.05) than that of the control group.These results indicated that both lactic acid bacteria and metabolites play an important role on intestinal microflora balance,nonspecific immunity and growth of sea cucumber,but the difference between the experimental groups was not significant.The metabolites may play a major role of probiotics in the process of sea cucumber farming.