Dietary microorganism and plant effects on the survival and immune response of Litopenaeus vannamei challenged with the white spot syndrome virus.

Abstract

The effect of plants and probiotics on the survival and immune response of Litopenaeus vannamei challenged with the white spot syndrome virus (WSSV) was evaluated. A probiotic mixture (PM), plant extract (PE) or powdered plants (PP) were added to feed with the attractant Dry Oil. An experiment was conducted with ¢ve treatments in triplicate. Shrimp were cultured in120 L plastic tanks and fed twice a day with commercial feed plus additives orwith commercial feed plusWSSV. Animals weremonitored for the occurrence ofWSSVusing single- step and nested PCR. The PMand PP added to the commercial feed showed high survival, a decrease in WSSVprevalence in shrimp and an increase in the activity of lysosomal enzymes, N-acetyl-b-glucosaminidase and acid phosphatase. The total haemocyte count in shrimp treated with PM was signi¢cantly higher than that in the control group (treatment I) and in shrimp fed with PE. The results of the present work indicate that PP and PMare good candidates for use as feed additives againstWSSVin shrimp cultures.