Effects Of Vitamin C On Growth And Antioxidant Ability Of Largemouth Bass (Micropterus Salmoide)

1. A75-day feeding experiment was carried out to investigate effects of oxidizedfish oil and different levels of vitamin C on growth and antioxidant ability of juvenilelargemouth bass (Micropterus salmoide) fed six isonitrogenous (45.7%) andisoenergetic diets.Test diets were formulated with two different quality of fish oil，fresh oil and oxidized fish oil. Fresh fish oil with2levels of vitamin C (0and700ppm), the oxidized fish oil with4levels of vitamin C (0,350,700and1400ppm).The peroxide value (POV) of fresh and oxidized fish oil was7.67and128.47meq/kgoil,respectively.These test diets were abbreviated to FF0, FF700，OF0，OF350，OF700and OF1400.After75days, evaluated the effect of oxidized fish oil and vitamin C ongrowth and antioxidant capacity of the large mouth bass. Results showed that thesurvival rate of the large mouth bass have significant differences among groups (P＜0.05). GSH-PX activities in liver of group OF0were significantly the lowest amongtest groups with oxidized fish oil. In conclusion, dietary oxidized fish oil increased theoxidative stress condition of large mouth bass, but more than700mg/kg dietarysupplement would improve growth and health of juvenile large mouth bass.2. An8weeks feeding experiment was conducted to determine the effects of dietaryvitamin C on the survival,growth, antioxidant ability，tissue ascorbic contents ofjuvenile largemouth bass (Micropterus salmoide) with initial weight of6.67±0.03g.Six isonitrogenous (45.7%) and isoenergetic diets were formulated to contain0,35,70,175,350and1050mg ascorbic acid equivalent kg1diet, with L-ascorbyl-2-polyphosphate (LAPP) as the supply form. These test diets wereabbreviated toVC0, VC35，VC70，VC175，VC350， and VC1050. Results showedthat the specific growth rate (SGR)(from2.81to3.41%d1) had an increasing trendwith the increase of dietary vitamin C, and significant difference was observed amongdietary treatments. Gross deficiency signs were observed only in group VC0fish.Survival rate, however, significantly the lowest in groupVC0(only(87.78±12.62)%)among all the test groups （P＜0.05）. The vitamin Ccontents in plasma, liver and muscle correlated positively with the vitamin C in diets.However, The MDA contents in plasma, liver and muscle correlated negatively withthe vitamin C in diets. The activities of superoxide dismutase (SOD), Oxidizedglutathione（GSH-PX）and glutathione (GSH), total antioxidant capacity (T-AOC),catalase (CAT) in livers and muscle significantly increased with increasing dietaryvitamin C. These results suggested that vitamin C significantly influenced the growthand the indexes about immune response of juvenile large mouth bass. In conclusion,the proper dietary vitamin C is175mg/kg, and this level of vitamin C can satisfyjuvenile large mouth bass the need to grow well and keep good health.