Nocardiopsis lucentensis AJ1 ANTIMICROBIAL SECONDARY METABOLITES INHIBIT VIRAL MULTIPLICATION AND STIMULATE IMMUNE SYSTEM IN INDIAN WHITE SHRIMP Fenneropenaeus indicus AGAINST WHITE SPOT SYNDROME VIRUS INFECTION

Antimicrobial secondary metabolites which obtained from the haloalkaliphilic Nocardiopsis lucentensis AJ1 were coated to the artificial diets at different concentrations (100 (NL1), 300 (NL2) and 500 (NL3) mg/g diets) and fed to the Indian white shrimp F. indicus (9.0 ± 0.5 g) for 30 days. After the feeding trails, control and experimental shrimp groups were challenged with virulent WSSV by oral infection. The diets NL2 and NL3 were highly influenced to improve the survival at more than 70 % and reduced viral load at less than 30 % by double step PCR detection after WSSV challenge. The experimental diets showed significant (P<= 0.01) differences in protein and glucose levels, improved total haemocyte count (THC), decreased coagulation times and higher oxyhaemocyanin levels when compared to the control diet fed shrimp groups. Moreover the NL diets helped to significantly increased (P <= 0.001) prophenol oxidase, intracellular superoxide anion production and lysozyme activity compared to the control groups. Due to the presence of surfactin molecules in the metabolites, they were effectively controlled the WSSV at in vivo condition and boosted the immune system. The findings will help to develop novel antiviral drugs against WSSV.