The aim of the present study was to evaluate the potential effects of olive leaf (Olea europea L.) extract (OLE) on common carp (Cyprinus carpio) health in response to ambient ammonia toxicity. Fish were fed with experimental diets containing OLE (0, 1, 5 and 10 g/kg) for 60 days followed by a 3‐hr challenge with ammonia (0.5 mg/L unionized ammonia‐N). Results showed that haemoglobin levels, differential leucocyte counts and mean corpuscular haemoglobin concentration were not affected by dietary OLE levels and ammonia challenge. Ammonia challenge significantly increased red blood cells and decreased blood mean corpuscular volume, mean corpuscular haemoglobin, plasma lysozyme, complement and bactericidal activities. Plasma lysozyme, complement and total immunoglobulin values improved by 5 and/or 10 g OLE/kg supplementation. Before the ammonia exposure, the 5 and 10 g OLE/kg treatment significantly increased blood white blood cell, but there was no significant difference among the treatments after the ammonia exposure. Ammonia exposure significantly increased plasma malondialdehyde levels; however, 1 and 5 g OLE/kg treatments had significantly lower values compared to the other treatments. The present results suggest that 1 g OLE/kg diet may improve fish health and reduce the adverse effects of ammonia toxicity on common carp.

中文翻译：

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用补充橄榄叶提取物的饮食喂养并接受环境氨处理的鲤鱼的血液学和免疫反应增强

本研究的目的是评估橄榄叶 (Olea europea L.) 提取物 (OLE) 对鲤鱼 (Cyprinus carpio) 健康的潜在影响，以应对环境氨毒性。给鱼喂食含有 OLE（0、1、5 和 10 g/kg）的实验性饮食 60 天，然后用氨（0.5 mg/L 非离子氨-N）挑战 3 小时。结果表明，血红蛋白水平、白细胞分类计数和平均红细胞血红蛋白浓度不受饮食 OLE 水平和氨挑战的影响。氨刺激显着增加红细胞并降低血液平均红细胞体积、平均红细胞血红蛋白、血浆溶菌酶、补体和杀菌活性。血浆溶菌酶、补体和总免疫球蛋白值通过 5 和/或 10 克 OLE/kg 补充剂得到改善。氨暴露前，5 和 10 g OLE/kg 处理显着增加血白细胞，但氨暴露后处理之间没有显着差异。氨暴露显着增加血浆丙二醛水平；然而，与其他处理相比，1 克和 5 克 OLE/kg 处理的值显着降低。目前的结果表明，1 g OLE/kg 饲料可以改善鱼类健康并减少氨毒性对鲤鱼的不利影响。