Little is known about the impacts of dietary exposure to inorganic mercury (Hg) for a long duration on the health indicators, growth, and disease resistance in Oreochromis niloticus. Accordingly, the current study was designed to assess the effects of Hg contaminated diets on blood biochemistry, growth, chemical composition, Hg bioaccumulation in the tissues, histopathology of liver and head kidneys, and disease resistance to Aeromonas hydrophila of O. niloticus. Also, the efficiency of citronella oil, geranium oil (GO), curcumin (CUR), Bacillus toyonensis (BT), and Bacillus subtilis (BS) as dietary supplements on reversing the negative impacts of Hg were assessed. A total of 240 tilapia fingerlings were assigned to eight dietary treatments fed on the basal diet (G1), G1 diet contaminated with 50 ppm Hg (G2), whereas the other groups fed the G2 diet and enriched with 400 mg CO (G3), 400 mg GO (G4), 200 mg CUR (G5), 7 × 107 cells BT (G6), 7 × 107 cells BS (G7), and 7 × 107 BT + BS/ kg diet (G8) for 16 weeks. The obtained results showed that fish fed on the G2 diet had significantly impaired growth performance indicators, blood parameters, and resistance to bacterial infection compared with fish in the control group. Additionally, distinct pathological perturbations in liver and head kidneys were observed. In contrast, fish groups G3 to G8 had a significant enhancement in the growth performance, Hg bioaccumulation in fish tissues, blood biochemistry, and resistance against A. hydrophila infection compared with fish in the G2 group. Maximum improvement was recorded in G5, G6, and G8. Conclusively, from both health and an economic point of view, these results suggested that several benefits might be gained by adding these additives, especially CUR, BT, and BT + BS, on growth enhancement and ameliorating Hg negative impacts in O. niloticus.

中文翻译：

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无机汞和饮食安全的饲料添加剂丰富了饮食，对尼罗罗非鱼（Oreochromis niloticus）的生长，免疫，组织生物蓄积和抗病性产生影响。

长期饮食饮食对尼罗罗非鱼的健康指标，生长和抗病性的影响知之甚少。因此，本研究旨在评估受汞污染的饮食对血液生化，生长，化学成分，组织中汞生物富集，肝脏和头肾脏的组织病理学以及对尼罗罗非鱼嗜水气单胞菌的抗病性的影响。此外，还评估了香茅油，天竺葵油（GO），姜黄素（CUR），Toyonensis芽胞杆菌（BT）和枯草芽孢杆菌（BS）作为膳食补充剂在逆转Hg负面影响方面的效率。总共将240种罗非鱼鱼种分配给以基础饮食（G1），被50 ppm汞（G2）污染的G1饮食，而其他组则以G2饮食为食，并富含400 mg CO（G3），400 mg GO（G4），200 mg CUR（G5），7×107细胞BT（G6），7×107细胞BS（G7），和7×107 BT + BS / kg饮食（G8），持续16周。获得的结果表明，与对照组的鱼相比，以G2饮食喂养的鱼的生长性能指标，血液参数和对细菌感染的抵抗力明显受损。另外，在肝脏和头肾脏中观察到明显的病理学扰动。相反，与G2组相比，G3至G8组鱼的生长性能，鱼类组织中Hg的生物蓄积，血液生化以及对嗜水链球菌感染的抵抗力显着增强。G5，G6和G8记录了最大的改进。最后，从健康和经济角度来看，