Abstract
Disease outbreaks will likely occur frequently with intensive cage cultures. Hence protective strategies are needed, and an effective approach is to enhance the piscine immune system. In this experiment, the effects of oral administered Plant Mineral Mixture, a mineral mixture derived from wild plants, on the prevention and the extermination of skin fluck disease of amberjack, which is caused by the parasite Benedenia seriolae, and on the non-specific biodefense activity of amberjack Seriola dumeruili were examined. Fish were divided into 2 groups : the control was fed a commercial diet and the mineral group was fed the same commercial diet containing 0.05 to 0.06% Mineral Mixture at 6 to 7% of fish body weight every two or three days, respectively. The dose of Mineral Mixture was about 45mg/kg body weight/day every two or three days. Fish were cultured for 13 weeks. The number of B. seriolae on the fish skin decreased significantly in the mineral group. A significant increase in non-specific biodefense activities such as the number of skin mucous cells (that is, skin mucous secretion volume), lyso-enzyme activity and lectine activity in skin mucus, the number of phagocytes and lymphocytes, the phagocytic activity and NBT reduction ability of granulocyte, the activity of natural killer (NK) like cell, the alternative pathway of complement activity (ACH50) and lyso-enzyme activity in plasma were also found in the fish with oral administered Plant Mineral Mixture. These results suggest that the oral administration of Plant Mineral Mixture enhanced the non-specific biodefence activity, and was effective for preventing and exterminating skin fluck disease in amberjack.
