圆斑星鲽幼鱼饲料中适宜的维生素C含量

Optimal Dietary Vitamin C Content for Juvenile Spotted Halibut (Verasper variegates)

本试验通过研究饲料中维生素C含量对圆斑星鲽幼鱼生长及消化、吸收、抗氧化、免疫功能的影响,以期得到圆斑星鲽幼鱼饲料中适宜的维生素C含量。试验在（12.5±1.5）℃的水温下进行,选择体重为（38.0±0.8）g的健康圆斑星鲽幼鱼,随机分为7组（每组3个重复,每个重复30尾）,分别投喂维生素C含量为10.2、249.1、402.8、616.2、769.5、909.4和1 177.8 mg/kg的试验饲料。试验期为8周。结果表明：616.2 mg/kg维生素C组的增重率、饲料效率、摄食率均为最高,其增重率显著高于10.2和909.4 mg/kg维生素C组（P〈0.05）,饲料效率显著高于其他各组（P〈0.05）,摄食率显著高于除1 177.8 mg/kg维生素C组外的其他各组（P〈0.05）。达到组织肝脏和肌肉最大维生素C积累量的饲料维生素C含量为769.5 mg/kg。616.2和769.5 mg/kg维生素C组的血清中丙二醛含量显著低于除402.8 mg/kg维生素C组外的其他各组（P〈0.05）;402.8 mg/kg维生素C组的血清中过氧化氢酶和溶菌酶活力最高,显著高于其他各组（P〈0.05）;402.8、616.2、769.4 mg/kg维生素C组血清中超氧化物歧化酶活力显著高于其他各组（P〈0.05）。饲料维生素C含量为402.8、616.2或769.4 mg/kg时,胃和肠道蛋白酶、淀粉酶、脂肪酶均处在较高水平。饲料中维生素C含量在249.1-616.2 mg/kg时可提高肠道皱襞高度,增加肠壁厚度,促进肠道黏膜生长。结果显示：饲料中维生素C含量在402.8-616.2 mg/kg时能有效满足圆斑星鲽幼鱼的生长需求,并可提高抗氧化能力、非特异性免疫力和消化吸收能力。

This experiment was conducted to study the effects of dietary vitamin C content on growth and the functions of digestion,absorption,antioxidant and immune of juvenile spotted halibut（Verasper variegates）,in order to get the optimal dietary vitamin C content for juvenile spotted halibut.Water temperature was maintained at（12.5 ± 1.5） ℃ in this experiment.Juvenile spotted halibut with the body weight of（38.0 ± 0.8） g were randomly assigned into 7 groups with 3 replicates per group and 30 fish per replicate,and fed 7 experimental diets with the vitamin C content were 10.2,249.1,402.8,616.2,769.5,909.4 and 1 177.8 mg/kg,respectively.The experiment lasted for 8 weeks.The results showed as follows： the highest weight gain rate,feed efficiency ratio and feeding rate were found in 616.2 mg/kg vitamin C group.The weight gain rate of 616.2 mg/kg vitamin C group was significantly higher than that of 10.2 and 909.4 mg/kg vitamin C groups（P〈0.05）,the feed efficiency ratio of 616.2 mg/kg vitamin C group was significantly higher than that of other groups（P〈0.05）,and the feeding rate of 616.2 mg/kg vitamin C group was significantly higher than that of other groups except 1177.8 mg/kg vitamin C group（P〈0.05）.The fish had the maximal liver and muscle vitamin C accumulation when dietary vitamin C content was 769.5 mg/kg.Serum malondialdehyde content of 616.2 and 769.5 mg/kg vitamin C groups was significantly lower than that of other groups except 402.8 mg/kg vitamin C group（P〈0.05）.The activities of serum catalase and lysozyme in 402.8 mg/kg vitamin C group had the highest values,which were significantly higher than those of other groups（P〈0.05）.Serum superoxide dismutase activity of402.8,616.2 and 769.4 mg/kg vitamin C groups was significantly higher than that of other groups（P〈0.05）.Protease,amylase and lipase activities in stomach and intestine were at a high level when dietary vitamin C content was 402.8,616.2 or 769.4 mg/kg.Dietary vitamin C content within the scope of 249.1 to 616.2 mg/kg could promote the growth of the intestinal mucosa and increase the fold height and intestinal wall thickness.These results suggest that dietary vitamin C content within the scope of 402.8 to 616.2 mg/kg can effectively meet the need of growth,and improve the antioxidant capacity,non-specific immunity,digestion and absorption ability of juvenile spotted halibut.