本试验旨在研究蛋氨酸对幼建鲤疾病抵抗能力及免疫应答的影响。选择体重为(12.34±0.02) g健康建鲤864尾，平均分成6组，每组144尾 (每组设3个重复，每个重复48尾)，分别饲喂蛋氨酸水平为0.39%、0.70%、1.00%、1.30%、1.60%和1.90%的饲料，饲养60 d后用嗜水气单胞菌攻毒17 d，考察蛋氨酸对幼建鲤免疫功能的影响。结果表明：适宜蛋氨酸水平极显著提高了攻毒前头肾体指数、后肾体指数、脾体指数、血液红、白细胞数量和攻毒后红细胞数量(P<0.01)；显著提高了攻毒前白细胞吞噬率和攻毒后成活率、白细胞数量、白细胞吞噬率、血清酸性磷酸酶活力、溶菌酶含量、补体C3含量、凝集素水平和抗嗜水气单胞菌抗体效价(P<0.05）。由此得出，蛋氨酸通过增强白细胞吞噬能力和提高特异性抗体效价从而提高幼建鲤的非特异性和特异性免疫力，增强疾病抵抗力。

This experiment was conducted to study the effects of methionine on immune response and disease resistance of juvenile Jian carp (Cyprinus carpio var. Jian). Eight hundred sixty-four juvenile Jian carp with an initial body weight of (12.34±0.02) g were randomly allocated to 6 groups with 3 replicates each and 48 fish in each replicate . Methionine supplemental levels in the diets of 6 groups were 0.39%, 0.70%, 1.00%, 1.30%, 1.60% and 1.90%, respectively. After 60 days of feeding, a challenge trial was conducted by injection of Aeromonas hydrophila for 17 d to study the effects of methionine on immune function of juvenile Jian carp. The results indicated that suitable methionine levels in diet could significantly improve the head kidney index, hind kidney index, spleen index, erythrocyte and leukocyte counts and erythrocyte count post challenge (P<0.01); significantly elevate the leukocyte phagocytosis rate in growth trail, and significantly increase the survival rate, leukocyte count, leukocyte phagocytosis rate, acid phosphatase activity, lysozyme activity, complement component C3, agglutinin level in plasma and antibody titers after injection with Aeromonas hydrophila (P<0.05). In summary, methionine could improve nonspecific and specific immunity in juvenile Jian carp by enhancing the phagocytic activity of leukocyte and increasing Aeromonas hydrophila antibody titer, and subsequently elevate the disease resistance.