茶多酚对草鱼免疫力及抗病力的影响

Effect of tea polyphenols on immunity and disease resistance of grass carp

试验旨在探究饲料中添加茶多酚对草鱼免疫性能和抗病力的影响。5组草鱼分别饲喂基础饲料中添加0(对照组)、200、400、600、800 mg/kg茶多酚的试验饲料,连续投喂8周后对草鱼的血清免疫指标进行测定。试验首先测定茶多酚对嗜水气单胞菌、杀鲑气单胞菌和荧光假单胞菌鱼类常见病原菌的抑制作用。结果显示,嗜水气单胞菌和荧光假单胞菌的抑菌敏感性显著高于杀鲑气单胞菌(P<0.05),筛选嗜水气单胞菌为攻毒试验所用菌种。饲养结束后,用嗜水气单胞菌对各组草鱼进行攻毒试验,对疾病感染情况下草鱼的存活率进行测定。结果显示:与对照组相比,饲料中添加400、600、800 mg/kg茶多酚,能显著提高SOD、CAT、AKP、LYZ的活性(P<0.05),饲料中添加400、600、800 mg/kg茶多酚,能显著降低血清中MDA活性(P<0.05);添加400、600、800 mg/kg茶多酚添加组的存活率较对照组差异显著(P<0.05)。结果表明,饲料中添加茶多酚能促进强化草鱼天然免疫反应和抗病力,饲料中茶多酚的添加量以400 mg/kg为宜。

The purpose of the experiment is to explore the effect of tea polyphenols on the immunity and disease resistance of grass carp.Five groups of grass carp were fed with 0(control group),200,400,600,800 mg/kg tea polyphenol test feed,respectively.After eight weeks of continuous feeding,the serum immune indexes of grass carp were measured.The inhibition of tea polyphenols on Aeromonas hydrophila,Aeromonas salmon and Pseudomonas fluorescens were tested.The results showed that the antimicrobial sensitivity of Aeromonas hydrophila and Pseudomonas fluorescens was significantly higher than that of Aeromonas salmon(P<0.05).Aeromonas hydrophila was selected as the strain for the test.At the end of feeding,Aeromonas hydrophila was used to test the survival rate of grass carp.The results showed that the activity of SOD,CAT,AKP and LYZ were significantly increased by adding 400,600 and 800 mg/kg tea polyphenols in the feed compared with control group(P<0.05),and the activity of MDA in the serum was significantly decreased by adding 400,600 and 800 mg/kg tea polyphenols in the feed(P<0.05);the survival rate of the group added 400,600 and 800 mg/kg tea polyphenols was significantly lower than that of control group(P<0.05),and the survival rate of the group added 400,600 and 800 mg/kg tea polyphenols was significantly lower than that of control group(P<0.05).To sum up,adding tea polyphenols to the feed can enhance the natural immune response and disease resistance of grass carp,and the appropriate amount of tea polyphenols in the feed is 400 mg/kg.