IMMUNE ENHANCEMENT AND UP-REGULATING IMMUNE-RELATED GENES EXPRESSION IN VANNAMEI SHRIMP Litopenaeus vannamei BY CRUDE FUCOIDAN ISOLATED FROM TROPICAL BROWN ALGAE  

Little study on fucoiodan from tropical brown algae and its bioactivity as immunostimulant in shrimp is found up to now. The purpose of this research were to know the innate immune response and immune-related genes expression of white shrimp, L.vannamei, that was administrated by crude fucoidan from tropical brown algae.

Crude fucoidan was isolated from three brown algae i.e. Sargassum sp., Padina sp., and Turbinaria sp. that were collected from Gunung Kidul coasts, Yogyakarta. The fucoidan was characterized by thin layer crhomatography (TLC) and FT-IR. Fucoidan was administered orally by supplementing in vannamei feed at dosages of 2,5 and 5 g kg^-1 feed of each brown algae. Response immune parameters including total hemocyte count (THC), phagocytic activity (PA), phagocytic index (PI), phenol oxidase (PO) activity, superoxide dismutase (SOD), and total protein plasma (TPP) was evaluated at 0, 4, 8, and 12 day post treatment (DAT). Immune-related genes expression include lectin, Toll, LGBP, and proPO was performed by real time qPCR from the selected shrimp haemolymph based on response immune parameters. The β-actin gene was used as an internal control (IC).

Results showed that crude fucoidan isolated from Sargassum sp. overally enhanced non-specific immune resoponse of shrimp vannamei better than Padina sp and Turbinaria sp. Significat increase in non-specific immune response of vannamei shrimp was observed at 4 DAT for THC and PA parameters. Whereas, SOD and TPP increased significantly at 8 DAT. PO activity was observed later at  12 DAT. There was no significant increase in IP after fucoidan treatment. The C_T analysis showed that immune-related genes were up-regulated in the range of 2 to 20 fold comparing to IC. The Toll gene of shrimp administered with fucoidan Sargassum sp. was highest upregulated. This research suggest that fucoidan from tropical Sargassum sp. have big opportunity to be developed as micronutrient supplement in shrimp feed to enhance immune response.