Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, 4511, Egypt.
Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Zagazig University, Zagazig, 4511, Egypt.
Aquat Toxicol. 2020 Mar;220:105406. doi: 10.1016/j.aquatox.2020.105406. Epub 2020 Jan 10.
Currently, feed adulteration and contamination with melamine (MEL) are considered one of the serious issues in the aquatic industry. With the limited studies of MEL exposure alone in fish, its adverse impacts on fish cannot be evaluated well. Accordingly, this study aimed to investigate the effects of MEL containing diets on the immune response, disease resistance to Aeromonas hydrophila, growth performance, chemical composition, immune-related genes expression, and histopathology of both spleen and head kidneys. Also, the efficacy of curcumin (CUR) dietary supplementation to alleviate MEL negative impacts were evaluated. A total of 180 apparently healthy Oreochromis niloticus (O. niloticus) were divided into four groups with three replicates fed the basal diet only, basal diet fortified with 200 mg/kg CUR, basal diet containing 1 % MEL, or a basal diet containing CUR + MEL. The results displayed that MEL significantly reduced growth performance indices and body crude lipid contents. Anemic, leukopenic, lymphocytopenic, heterocytopenic, esonipenic, hypoproteinemic and hypoalbuminic conditions were apparent. Moreover, depleted immune and antioxidant indicators including lysozyme activity, nitric oxide, immunoglobulin M, complement 3, glutathione peroxidase, and superoxide dismutase enzyme activity were recorded. Also, MEL reduced the disease resistance of O. niloticus to bacterial infection. Furthermore, MEL induced downregulation of mRNA levels of interleukin 1β and tumor necrosis factor α in the spleen together with obvious pathological perturbations in both spleen and head kidneys. The CUR addition resulted in a significant enhancement in most indices. These results may conclude that MEL could alter both innate and adaptive immune responses via the negative transcriptional effect on immune-related genes together with the oxidative damage of the immune organs. Furthermore, CUR dietary supplements could be advantageous for mitigating MEL negative impacts, thus offering a favorable aquafeed additive for O. niloticus.
目前，饲料掺假和三聚氰胺（MEL）污染被认为是水产养殖业的严重问题之一。由于单独研究鱼类对 MEL 的暴露，其对鱼类的不良影响无法得到很好的评估。因此，本研究旨在研究含 MEL 的饮食对鱼类免疫反应、对嗜水气单胞菌的抗病能力、生长性能、化学成分、免疫相关基因表达和脾和头肾组织病理学的影响。同时，评估姜黄素（CUR）饮食补充缓解 MEL 负面影响的效果。总共 180 条明显健康的尼罗罗非鱼（Oreochromis niloticus）分为四组，每组三个重复，分别饲喂基础饲料、基础饲料添加 200mg/kg CUR、基础饲料添加 1% MEL 或基础饲料添加 CUR+MEL。结果表明，MEL 显著降低了生长性能指标和体粗脂肪含量。出现贫血、白细胞减少、淋巴细胞减少、异细胞减少、嗜酸性粒细胞减少、低蛋白血症和低白蛋白血症。此外，记录到免疫和抗氧化指标的消耗，包括溶菌酶活性、一氧化氮、免疫球蛋白 M、补体 3、谷胱甘肽过氧化物酶和超氧化物歧化酶活性。此外，MEL 降低了 O. niloticus 对细菌感染的抵抗力。此外，MEL 导致脾中白细胞介素 1β和肿瘤坏死因子 α 的 mRNA 水平下调，同时脾和头肾均出现明显的病理扰动。CUR 的添加显著提高了大多数指标。这些结果表明，MEL 可能通过对免疫相关基因的负转录效应以及对免疫器官的氧化损伤来改变先天和适应性免疫反应。此外，CUR 饮食补充剂可能有利于减轻 MEL 的负面影响，因此为 O. niloticus 提供了一种有利的水产饲料添加剂。
