饲料中添加雨生红球藻对七彩神仙鱼生长、体色及抗氧化力的影响

为探讨雨生红球藻(Haematococcus pluvialis)对七彩神仙鱼(Symphysodon haraldi)增色效果以及对机体抗氧化力的影响,分别用添加0(对照组)、3.33、6.66、9.99、13.32和16.65 g/kg雨生红球藻(折算成虾青素添加量分别为0、100、200、300、400和500 mg/kg饲料)的饲料饲喂七彩神仙鱼6周,测定七彩神仙鱼皮肤、鳍条、肌肉和肝脏中的虾青素含量、体表的三刺激值和肝脏总抗氧化能力(T-AOC)和谷胱甘肽(GSH)含量。结果显示:饲料中添加雨生红球藻可以显著提高七彩神仙鱼的增重率,当添加量为9.99 g/kg其增重率最大。七彩神仙鱼皮肤、鳍条、肌肉和肝脏虾青素含量随着雨生红球藻添加量的增加而升高,当雨生红球藻添加量超过6.66 g/kg,各组织中虾青素的含量趋于稳定。随着雨生红球藻添加量增加,皮肤L*值(亮度)下降、而a*值(红度)和b*值(黄度)升高,皮肤中虾青素含量与三刺激值间的相关性均达到高度相关,并与a*值的相关性最高。随着雨生红球藻添加量的增加,七彩神仙鱼肝脏的T-AOC和GSH的含量也逐渐升高。结果表明,在饲料中添加雨生红球藻可提高七彩神仙鱼的增重率,提高七彩神仙鱼皮肤虾青素含量,改善七彩神仙鱼体色,增强机体的抗氧化能力;雨生红球藻的添加量建议为6.66~9.99 g/kg(虾青素含量为200~300 mg/kg)。

Effect of Haematococcus pluvialis on growth,body color and antioxidation capacity of discus fish Symphysodon haraldi

The present study was conducted to evaluate the effects of dietary Haematococcus pluvialis on body color and an-tioxidation capacity of discus fish Symphysodon haraldi. Six diets were prepared with the supplementation of H. pluvialis at levels of 0 (control), 3. 33, 6. 66, 9. 99, 13. 32 and 16. 65 g/kg diet (0, 100, 200, 300, 400 and 500 mg/kg astax-anthin) , and fed to juvenile discus with initial body weight of 16. 74 ± 0. 65 g. After 6 weeks rearing, H. pluvialis signifi-cantly stimulated the growth of discus fish, and the discus fish had the highest weight gain when the addition level was 9. 99 g/kg. The L?values gradually decreased with the increasing H. pluvialis supplemented level. The a?、 b?value and astaxanthin content in skin of fish fed H. pluvialis supplemented diets were significantly higher than those of the control fish (P<0. 05). The L?、 a? and b? values of skin were highly correlated to the astaxanthin contents in skin of discus fish. The total antioxidation capacity ( T-AOC) and glutathione ( GSH) of liver in the H. pluvialis supplemental groups was sig-nificantly higher than those of control group (P<0. 05). The results indicate that supplementing H. pluvialis in diet could enhance the astaxanthin content in skin, improve the body color and promote the antioxidant capacity of discus fish. The supplemental level of H. pluvialis was suggested to be 6. 66~9. 99 g/kg (200~300 mg/kg astaxanthin).