Abstract
Efficacy of an algine-based immunomodulator, Ergosan was tested on growth and survival of early larval stages (nauplii - PL3) of Indian white shrimp, Fenneropenaeus indicus in fibreglass tanks (10,000 l) for two larval rearing cycles. Larvae fed on a diet with Ergosan were considered as treatment and those fed on a diet without Ergosan as control. Both control and treatments were replicated in five tanks and arranged in a completely randomized design. Significant difference (P < 0.01) in survival was observed between control and treatment. However, growth of larvae was not influenced by the supplementation of Ergosan. Total colony forming units, yellow, green Vibrio and luminescent bacterial colonies were found to be significantly decreased in treatment tanks. Thus Ergosan was found to be a safe immunomodulator for improving larval survival and reducing bacterial load in rearing water.