Survival of L. plantarum fed shrimp relatively increased with the harmony to THC level reflecting shrimp capability to react against foreign materials as the circulating hemocytes plays important roles in the invertebrate immune responses. THC level varies in
response to infection, environment changes and ecdysis in most crustaceans. The result correlated with the LAB fed shrimp ability toremove 1 log CFU ml_1 of vibrio from the haemolymph within 3 h, while non-supplemented shrimp was not capable. Similar result
was reported by [16], feeding of two LAB strains, isolated from juvenile shrimp (L. vannamei) and inhibitory against V. harveyi, improved L. vannamei larvae survival to 44 and 50%, compared with 21% survival of control shrimp. In addition, L. plantarum isolated
from L. vannameibroodstock shrimps was also reported about its action as an immunostimulant (increase of PO activity and THC after V. harveyi injection) within 6 days as well as increased LAB in the digestive tract [16]. Moreover, administration of L. plantarumin the diet at 1010 CFU (kg diet) induced immune modulation and enhanced the immune ability (increase of phenoloxidase activity, superoxide dismutase activity, and clearance efficiency as well as prophenoloxidase and peroxinectin (PE) mRNA transcription) of L. vannamei, hence increase of shrimp resistance to V. alginolyticusinfection [5]. Peptidoglycans of L. plantarumcell wall could also stimulate the immune system as Bf. thermophilumpeptidoglycans was shown to enhance the immunological parameters of Penaeus japonicus and the resistance to Vibrio penaeicidainfection proven by Itami et al. [30].