Probiotic for larviculture of portunus pelagicus (linnaeus, 1758)

In aquaculture, probiotics can be considered a valid alternative to the use of antibiotics and in particular, in fish larviculture, to prevent high mortality owing to microbes and to improve survival rate. Many researchers reported promising results using a single beneficial bacterial strain in the culture of many finfish species. Therefore, L. salivarius isolated from the gut of female Portunus pelagicus and its influence on larviculture was examined. Four trial experiments were triplicate and designed in three different administrations of probiotic 1.0×106 cfu mL−1 (T-1), 5.0×106 cfu mL−1 (T-2) and 1.0×107 cfu mL−1 (T-3) and one control without any probiotic, and were added to rearing water every day. Addition of the probiotic (to first day hatch larvae) significantly increased survival rate (p<0.05) for all treatments over controls. Probiotic concentration 5.0×106 cfu mL−1 (T-2) did produce highest survival rate of larvae. The microbial load particularly Vibrio sp. was dominant in the control tanks than in experimental tanks. The added probiotic affected pH in treated groups and the less nitrogen contents were observed in the experimental tanks mainly due to the effect of probiotic. The specific activities of protease and amylase enzymes were significantly higher (p<0.05) in all treated groups over the control and highest were determined in treated group T-2. The highest concentration of probiotic did not increase the survival and the activity of the digestive enzymes. The results of present study suggest that that treatment with probiotics, L. salivarius, at a certain concentration as water additives could be used to improve survival rate and water quality, thereby convalescing digestive enzymes activity of P. pelagicus.