The effects of dietary probiotic on survival and immune parameters of white leg shrimp (Litopenaeus vannamei)

Abstract

The aim of this study is to evaluate the effect of probiotic Bacillus spp. on survival rate and immune parameters of white leg shrimp (Litopenaeus vannnamei). A probiotic strain, Bacillus spp. was administered into diet for white leg shrimp at different dosages of 0.05%, 0.1%, and 0.2%. Experiment lasted for ten weeks. In comparison to control group, survival rate, total number of haemocyte (HM) and hyaline cell (HC), and phenoloxidase (PO) activity were significantly different (P<0.05) in supplemental diets, whereas the number of granular cell (GC) of shrimp in the diet at 0.1% Bacillus spp. concentration was remarkably higher than others (P<0.05). After ten weeks of feeding trial, shrimps were challenged with Vibrio parahaemolyticus. The total number of HM and HC of shrimps in supplemental diets were significantly higher than the control treatment (P<0.05). Subsequently, a significantly higher of GC in shrimps fed diet at 0.1% Bacillus spp. concentration was found compared to other treatments (P<0.05). While, the accumulative mortality and Vibrio spp. density in supplemental diets decreased significantly compared to control diet (P<0.05), especially in 0.1% and 0.2% treatments. These findings demonstrate that administration of Bacillus spp. in supplemental diets can improve survival rate and disease resistance through an enhanced immune response in shrimp.