饲料中添加谷胱甘肽对草鱼生长、生理指标和抗病力的影响

选用初始体质量约8.50 g的草鱼(Ctenopharyngodon idella),在56 d的饲养期中分别投喂添加5种不同剂量谷胱甘肽(GSH)(添加量分别为0 mg/kg、100 mg/kg、200 mg/kg、300 mg/kg和400 mg/kg)的试验饲料,观察GSH对草鱼生长、生理指标和抗病力的影响。结果表明,饲料中添加GSH能够提高草鱼特定生长率、存活率和饲料效率。其中,300 mg/kg GSH组草鱼的特定生长率和400 mg/kg GSH组草鱼的存活率显著高于对照组;添加GSH各组草鱼的饲料效率均显著高于对照组,当添加量为200 mg/kg时草鱼饲料效率达到最高。与对照组相比,饲料中添加GSH的各组草鱼肝胰指数明显升高,其中200 mg/kg组达到显著水平。饲料中添加GSH能够提高血清IGF-1水平,其中300 mg/kg和400 mg/kg组显著高于对照组。与对照组相比,各实验组草鱼血液白细胞数目有不同程度升高,其中300 mg/kg和400 mg/kg组均达到显著水平。饲料中添加GSH可以提高草鱼对嗜水气单胞菌的抵抗能力,其中200 mg/kg GSH组草鱼攻毒后存活率达到最高。以特定生长率为判定指标,GSH在草鱼饲料中的适宜添加量为350 mg/kg。

Effect of dietary glutathione on growth,physiological indices and disease resistance in juveniles grass carp Ctenopharyngodon idella

The effects of varying dietary glutathione(GSH) levels(0,100mg/kg,200mg/kg,300mg/kg and 400mg/kg) on growth,physiological indices and disease resistance in grass carp,Ctenopharyngodon idella,juveniles with approximately 8.5g initial body weight were evaluated in 56days study.Five test diets were applied with triplicate tanks and 50 fish were stocked randomly in each tank.Feeding rate was 4% of wet body weight.The results indicated that specific growth rate(SGR) in fish fed 300mg/kg GSH and survival rate(SR) in fish fed 400mg/kg GSH were significantly higher than that of control group.And feed efficiency(FE) in fish fed the diets containing varying GSH levels was higher than control group.There was an increase of hepatosomatic index(HSI) in fish fed diets containing varying levels of GSH in comparison to the control group,and a significantly higher HSI was observed in fish fed 200mg/kg GSH diet.Content of IGF-1 in serum of grass carp fed diets containing varied GSH levels increased and it was significantly higher in fish fed 300mg/kg and 400mg/kg GSH diets than that of control group.White blood cell(WBC)count was studied to assess the non-specific immune response of grass carps.Dietary supplementation of GSH enhanced WBC in blood of grass carp fed diets containing varied levels of GSH and it was significantly higher in fish fed 300mg/kg and 400mg/kg GSH diet than control group.The disease resistance against Aeromonas hydrophila in fish fed varying dietary GSH levels was higher compared with the control group and its survival rate was optimum in fish fed 200mg/kg GSH diet.For grass carp juveniles,the optimum level of dietary GSH,determined by quadratic regression analysis,was 350mg/kg,on the basis of maximum special growth rate.