The economic loss of intestinal inflammation by histamine in diet has caused concern in eel culture; it is urgent to develop a natural feed additive to alleviate the negative effects of high-level dietary histamine. Oligomeric proanthocyanidins (OPCs), as the natural antioxidant to scavenge free radicals, were supplemented to alleviate the effects of dietary histamine on parameters of growth, serum biochemistry, and liver metabolites of juvenile American eels in the present study. Juvenile American eels with an initial body weight of 10.84 ± 0.16 g per fish were divided into a control group fed commercial diet, a HIS group fed commercial diet supplemented 300 mg/kg histamine, and an OPC group fed commercial diet supplemented 300 mg/kg histamine and 300 mg/kg OPC. The trial period was 11 weeks. Compared with the HIS group, the OPC group showed that dietary OPC supplementation could alleviate growth retardation; decrease activities of glutamic-pyruvic transaminase, glutamic-oxaloacetic transaminase, acid phosphatase, and alkaline phosphatase; and lower levels of immunoglobulin and complement 3 in serum. With the upregulation of L-cysteine and dihydrouracil involving cysteine and methionine metabolism, beta-alanine metabolism, sulfur metabolism, pantothenate and CoA biosynthesis, and pyrimidine metabolism in the liver, OPC supplementation could alleviate the effects of high-level dietary histamine on growth and serum biochemical parameters. There were no significant differences of growth performance and serum biochemical parameters between the HIS group and control group. These results indicated that OPC might act as a potential feed additive to effectively counteract the negative effects of dietary histamine on juvenile American eel.

中文翻译：

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低聚原花青素可抵消高水平膳食组胺对美洲鳗 (Anguilla rostrata) 的负面影响

饮食中组胺引起肠道炎症的经济损失引起了鳗鱼养殖的关注；迫切需要开发一种天然饲料添加剂来减轻高水平膳食组胺的负面影响。在本研究中，低聚原花青素 (OPCs) 作为清除自由基的天然抗氧化剂，被补充以减轻膳食组胺对美洲鳗幼鱼生长参数、血清生化和肝脏代谢物的影响。将每条初始体重为 10.84 ± 0.16 g 的美洲鳗幼鱼分为饲喂商业饲料的对照组、饲喂补充 300 mg/kg 组胺的商业饲料的 HIS 组和饲喂补充 300 mg/kg 组胺的商业饲料的 OPC 组组胺和 300 mg/kg OPC。试用期为 11 周。与 HIS 组相比，OPC 组表明，膳食补充 OPC 可以缓解生长迟缓；降低谷氨酸-丙酮酸转氨酶、谷氨酸-草酰乙酸转氨酶、酸性磷酸酶和碱性磷酸酶的活性；血清中免疫球蛋白和补体 3 水平较低。随着 L-半胱氨酸和二氢尿嘧啶的上调涉及半胱氨酸和蛋氨酸代谢、β-丙氨酸代谢、硫代谢、泛酸和 CoA 生物合成以及肝脏中的嘧啶代谢，补充 OPC 可以减轻高水平膳食组胺对生长和生长的影响。血清生化参数。HIS组与对照组的生长性能和血清生化指标无显着差异。