日粮中添加谷胱甘肽对虹鳟生长性能和抗氧化性能的影响

为研究日粮中添加谷胱甘肽对虹鳟Oncorhynchus mykiss生长性能和抗氧化性能的影响,选择初始体质量为(718.3±36.3)g的虹鳟,分别投喂添加5种不同水平的谷胱甘肽饲料(谷胱甘肽含量分别为0、100、200、400、600 mg/kg),8周后观测各组虹鳟的生长情况及机体抗氧化状态。结果表明:虹鳟的增重率(WGR)、特定生长率(SGR)、日均摄食量(AFI)随着饲料中谷胱甘肽添加量的增加均呈现先升高后降低的趋势,且在添加量为200 mg/kg时达到最大值,并显著高于其他各组(P0.05),而200 mg/kg组虹鳟的饲料系数(FCR)则显著低于对照组(P0.05),且死亡率最低(4.04%);谷胱甘肽添加组虹鳟血清、肝脏中超氧化物歧化酶(SOD)活性均升高,其中200 mg/kg组血清和肝脏中SOD显著升高(P0.05);谷胱甘肽添加组虹鳟血清、肝脏和鳃丝中过氧化氢酶(CAT)活性均高于对照组,且随着谷胱甘肽添加量的增加呈现先升高后降低的趋势,其中200 mg/kg组血清和肝脏中CAT活性显著高于对照组(P0.05);谷胱甘肽添加组虹鳟血清、肝脏和鳃丝中谷胱甘肽过氧化物酶(GSH)和谷胱甘肽还原酶(GR)活性均高于对照组,且随着谷胱甘肽添加量的增加呈现先升高后降低的趋势,其中200 mg/kg组血清、肝脏和鳃丝中GSH和GR活性均显著高于对照组(P0.05);谷胱甘肽添加组虹鳟血清、肝脏和鳃丝中丙二醛(MDA)含量均低于对照组,但均无显著性差异(P0.05),其中200 mg/kg组最低。研究表明,在循环水养殖模式下,饲料中添加适量谷胱甘肽能够提高虹鳟的生长性能,降低饲料系数和死亡率,有助于缓解虹鳟养殖过程中的氧化应激,提高抗氧化能力。

Effects of dietary glutathione on growth and anti-oxidative capability of rainbow trout Oncorhynchus mykiss

The rainbow trout Oncorhynchus mykiss with initial body weight of (718.3±36.3)g were reared in a recy-cling water system and fed diets containing glutathione ( GSH) at a rate of 0,100,200,400 and 600 mg/kg at water temperature of (15.0±1.0)℃ for 8 weeks to investigate the effects of dietary glutathione on the growth performance and antioxidant ability and resistance to nitrite exposure in rainbow trout. The results showed that average weight gain rate ( WGR) , specific growth rate ( SGR) and food intake ( FI) were found to be elevated first and then de-clined with increase in dietary SGR level, the maximum in the fish fed the diet containing 200 mg/kg of GSH and significantly higher than those in other groups ( P<0.05) . There was significantly lower food conversion ratio in 200 mg/kg group than in other groups (P<0.05), with the minimal mortality rate (4.04%). The gill filament and ser-um superoxide dismutase ( SOD) activities in GSH-fed fish were higher than those in the control group, significant-ly higher serum and hepatic SOD activities in 200 mg/kg GSH groups. The gill filament, serum and hepatic catalase ( CAT) activities were higher in GSH-fed fish than those in the control group, increase first and then decrease with elevated dietary GSH level, significantly higher serum and hepatic CAT activities in 200 mg/kg GSH groups( P<0.05). There were significantly lower malondialdehyde (MDA) levels in serum, liver and gill filament in GSH-fed fish than those in the control group, without significant difference( P>0.05) , and the minimum in the fish fed the diet containing GSH at a rate of 200 mg/kg. The findings indicate that supplementation of suitable amount of gluta-thione leads to improve the growth and antioxidant capacity of rainbow trout.