Antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae isolated from the rearing water of shrimp (Penaeus vannamei) postlarvae

Shrimp farming has experienced rising costs as a result of disease outbreaks associated with Vibrio spp. Suitable strategies for disease prevention and control are therefore urgently needed. This study aimed to evaluate the antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae in the rearing water of Pacific white shrimp (Penaeus vannamei) postlarvae. In vitro assays included the determination of minimum inhibitory concentration (MIC) of M. oleifera seed powder against V. cholerae, whereas in vivo assays included the effect of M. oleifera seed powder on bacterial load and water quality parameters in the rearing tanks, as well as its effect on shrimp postlarvae survival. M. oleifera seed powder inhibited the growth of V. cholerae with MIC values of 62 center dot 5 mu g ml(-1). Moreover, seawater pH of treated tanks (8 center dot 66) was significantly lower (P < 0 center dot 01) than pH of the control tanks (9 center dot 02), whereas the visibility of treated tanks (37 center dot 08 cm) was significantly higher (P < 0 center dot 01) as compared to control tanks (35 center dot 37 cm). Likewise, V. cholerae load was significantly reduced (P < 0 center dot 01) from 4 center dot 7 x 10(4) to 3 center dot 1 x 10(3) CFU per ml in tanks treated with M. oleifera seed powder. Altogether, this study demonstrates the antimicrobial activity of M. oleifera against V. cholerae in shrimp culture.