Performance of <i>Litopenaeus vannamei</i> (Boone, 1931) cultured with probiotic when submitted to infection by <i>Vibrio harveyi</i>

Abstract

The effect of probiotic in Litopenaeus vannamei juveniles when submitted to the infection by Vibrio harveyi was evaluated in the present study. The  exposure to V. harveyi was carried out during 15 days using individuals reared for 30 days in a closed recirculation system with a commercial probiotic (Bacillus subtilis and Bacillus licheniformis), added to water and food (PAR), only in the water (PA), only in the food (PR) and without probiotic (SP). Feed intake of shrimp differed significantly among treatments (P < 0.05). In the SP treatment, a significant reduction of intake occurred with the gradual development of inoculations of V. harveyi, showing positive effects of the probiotics in other treatments on this parameter. The PAR and PA treatments showed inferior and more constants values in the total haemocyte count during the experimental period. The highest growth rates were observed in the SP (0.45 ± 0.04 g/week) and PAR (0.34 ± 0.19 g/week) treatments, which did not differ statistically (P > 0.05). The results suggest that different answers can be found among cultures from autotrophic and heterotrophic media, when a bacterial infection occurs in L. vannamei.