Effects of Polysaccharide gel from Durain fruit-hall on growth and protection against microbial in fection in The black tider shrimp

Abstract

Growth performance in black tiger shrimp (Penaeus monodon) and its immunogenesis was evaluated on feeding with durian polysaccharide gel (PG) additive diet. Diets in treatment groups added 0.5, 1.0 and 2.0 grams PG in 100 grams diet, shrimp diet without PG was used in control group. Each group of black tiger shrimp was fed with the PG additive diets for 56 days in closed-recirculating water system pond. Body weight and total length of shrimps were measured after 4 weeks and 8 Weeks, respectively. Survival rate was observed. Immunogenesis was evaluated by the total hemocytes count and phenoloxidase activity test. The results showed that body weight of shrimp in 2.0% PG group was higher (P<0.05) than that of control after feeding for 8 weeks, long total length was also observed. Survival rate of shrimp in groups feeding with 0.5 and 1.0 % PG were significantly higher than that of control. Feed conversion ratio (FCR) of PG feeding groups were significantly lower (P<0.05) than that of control. Total hemocytes count and phenoloxidase activity in blood were higher (P<0.05) in groups feeding with 1.0 and 2.0% PG than that of control group. Oral administration of PG additive diet seemed to increase the survival shrimps against the impact of Vibrio harveyi 1526 and white spot syndrome virus (WSSV) infection in groups fed with 1.0 and 2.0% PG compared with control group. The survival rates of shrimps after 4 weeks prefeeding with 0.0, 0.5, 1.0 and 2.0% PG were 0, 0, 57 and 17%, respectively, at day 11 of WSSV infection; the relative percent survival (RPS) values at day 7 were 9, 94 and 51%, respectively. The survival rates after 8 weeks prefeeding were 0, 4, 4 and 33%, respectively, at day 14 of infection; RPS values at day 10 were -37, -63 and 11%, respectively. Prefeeding of the same three diet formulas for 8 weeks were provided continuously same survival rate at S0, 58, 67 and 75%, respectively, after day 4 of V. harveyi 1526 infection; RPS values at day 3 were 18, 32, and 50%, respectively. The disease resistance of P. monodon against WSSV in the treated groups of 4 weeks prefeeding 1.0% PG diets showed the best RPS value at 94% compared with the other treatments. The disease resistance of P. monodon against V. harveyi 1526 in the treated groups of 8 weeks prefeeding 2.0% PG diets possessed the highest RPS values only at 50%. These results indicate the possibility of PG affected P. manodon immune stimulation. The in vitro antibacterial activity determination of PG against a gram negative bacterium, V. harveyi 1526, demonstrated the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PG at 6.0 and 12.5 mg/ml, respectively. The results suggest that PG at 1.0% in diet stimulate growth and immune system of P. monodon shrimp juveniIes in this study.