Effects of Oxidized Konjac glucomannan (OKGM) on growth and immune function of Schizothorax prenanti

Abstract

Schizothorax prenanti is an important existemic commercial fish in River Yangtze. OKGM (Oxidized Konjac glucomannan) is a kind of polysaccharide oxidative degraded from KGM. Added 500, 1000, 2000, 4000, 8000 mg/kg OKGM into the diets of S. prenanti. After 60 days feeding trial, WGR (weight gain rate), SGR (specific growth rate), PER (protein efficiency ratio) of groups fed the diet with 8000 mg/kg OKGM was all significantly (P < 0.05) higher; FCR (feed conversion ratio) was significantly lower than the control group whose diet have no OKGM. Hepatopancreas index, spleen index of group 6 whose feed added 8000 mg/kg OKGM were significantly higher and gallbladder index was significantly lower than the control group. Erythrocyte number, leukocyte number of group 5, 6 whose feed added 4000, 8000 mg/kg OKGM were excellent significantly (P < 0.01) more than the control group. At the same time, Erythrocyte phagocytic rate, erythrocyte phagocytic index, neutrophilic granulocyte phagocytic rate, neutrophilic granulocyte phagocytic index of all the groups whose diet added OKGM were significantly higher than the control group. Content of IgM, C3 of group 4 whose feed added 2000 mg/kg OKGM were significantly more than the control group. As for activity of CAT, group 6 was significantly higher than the control group. When compared activity of SOD, group 6 was significantly higher than group 1, 2, 3. Accordingly, activity of GSH-Px of group 3, 4, 5, 6 were significantly higher than the control group. On the contrary, content of MDA, group 3, 4, 5, 6 whose feed added 1000–8000 mg/kg OKGM was excellent significantly lower than the control group. After injected Aeromonas hydrophila 21 days, only group 6 whose feed added 8000 mg/kg OKGM survived excellent significantly more than the control group. So we can draw a conclusion of that added OKGM in the diets of S. prenanti, not only promoted growth, but also improved immune function, and the best dose was 8000 mg/kg in this experiment.