Assessment of immune response in post-probiotic treated Litopenaeus vannamei challenged with Vibrio harveyi

Immunological responses of Litopenaeus vannamei fed with two probiotic bacteria, Bacillus licheniformis and Bacillus megaterium were evaluated at a post probiotic treatment scenario. This shrimp fed with the probiotics individually and in combination for 60 days was fed with normal feed and the immune response was evaluated at the 10th day post probiotic treatment (PPT). The immune response was reduced in all the treatments during the post probiotic treatment even though it was higher than the control. The probiotic treated shrimps were challenged with Vibrio harveyi after 5 days PPT and the immunological evaluation were carried out at the 10th day PPT. Probiotic fed shrimps showed significantly higher survival and immunological response than the control. Among the treatments, combination of the two probiotics enhanced the non-specific immunity significantly in the shrimps than the individual probiotic