EFFECTS OF DIETARY INCLUSION OF EXTRACTS FROM GANODERMA LUCIDUM ON GROWTH PERFORMANCE, IMMUNE RESPONSE AND DISEASE RESISTANCE IN GIBEL CARP (CARASSIUS AURATUS GIBELIO)

To investigate the effects of the administration of a glucan extract from Ganoderma lucidum to gibel carp (Carassius auratus gibelio) on non-specific immune parameters, growth and disease resistance, 5 different treatments were conducted: a) a control diet without any glucan extract for 65 days (0%-65d); b) the control diet with 0.6% glucan extract for 21 days and then switched on the control diet for 44 days (0.6%-21d, 0%-44d); c) the control diet with 0.6% glucan extraction for 65 days (0.6%-65d); d) the control diet with 3.0% glucan extract for 21 days and then switched on the control diet for 44 days (3%-21d, 0%-44d); and e) the control diet with 3.0% glucan extract for 65 days (3%-65d). Each diet was allocated randomly to triplicate groups of fish with an average basal weight of 6.72 g, and each tank (300 L) was stocked with 45 fish. Growth, serum lysozyme, alternative pathway of complement hemolytic activity, blood leucocyte phagocytic activity, respiratory burst, and myeloperoxidase activity were monitored at Day 21, 46 and 65. We observed that glucan extract had no significant effects on s growth rate (SGR) at the end point of the feeding trials (P0.05). In addition, dietary glucan extract increased the respiratory burst (P0.05) while reduced the alternative pathway of complement hemolytic activity (P0.05). The -glucan extract enhanced leucocyte phagocyitc activity in a dose-dependent pattern (P0.05). On Day 65, fish in Treatment C showed the highest survival rate for the challenge of Edwardsiella tarda (P0.05). These results suggested that dietary 3.0% glucan extract supplementation may enhance immunity and disease resistance for gibel carp.