Effect of fucoidan extracted from the brown seaweed, Sargassum johnstonii on growth, survival, immune response and disease resistance to vibrio parahaemolyticus in Penaeus vannamei Boone, 1931

Abstract

The present study was conducted to investigate the effect of fucoidan extracted from the brown seaweed, Sargassum johnstonii on immunological parameters and disease resistance to Vibrio parahaemolyticus in Penaeus vannamei (Boone, 1931) [8]. Four experimental diets were formulated with a 35% protein level in all diets. T0 diet was considered as a control, T1, T2, and T3 diets contained Sargassum johnstonii fucoidan extract (0.5, 1, and 2% respectively). Penaeus vannamei (average weight 0.012g) were stocked at a density of 20 nos. in each of the 21 experimental tanks. At the end feeding trial, shrimps were challenged with 0.1 ml of Vibrio parahaemolyticus suspension at the rate of 1×104 cfu ml-1 by selecting ten shrimps from each replication. The mortality was observed in all groups for 10 days. After the end of the experimental period, the result of this study shows that the highest prophenoloxidase activity, respiratory burst activity, and total haemocyte count were recorded in the 2% Sargassum johnstonii extracted fucoidan incorporated diet, while it was the lowest recorded in the control diet at the end of the experiment. In growth performance, mean weight gain, SGR and PER were higher in 2% Sargassum johnstonii extracted fucoidan incorporated diet, while lower in the control diet. FCR was better in the fucoidan extract-containing diet compared to the control diet. There was no significant difference in the survival rate of Penaeus vannamei in all treatments. After the challenge lower mortality rates were recorded in the 2% Sargassum johnstonii extracted fucoidan incorporated diet, while the mortality rate was higher in the control diet. Results of the study indicated that a diet prepared with Sargassum johnstonii extracted fucoidan could enhance the growth, immunological parameters, and disease resistance of Penaeus vannamei.