Ahmed Shaimaa A A, Ahmed Ali Adel Ali, Elshopakey Gehad E, Younis Elsayed M, Abdelwarith Abdelwahab A, Saad Mai Farag, Davies Simon J, Ibrahim Rowida E, Edrees Asmaa
Department of Aquatic Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, 44511, Zagazig, Egypt.
Department of Pharmacology, Faculty of Veterinary Medicine, Azzaytuna University, Tarhuna, Libya.
Vet Res Commun. 2025 Feb 18;49(2):107. doi: 10.1007/s11259-025-10661-8.
Nickel (Ni) as a waterborne metal pollutant is widespread and harms fish health. In this study, the effects of fortifying diets with 0.1% Melaleuca alternifolia (MO) and 0.1% Ocimum basilicum (BO) essential oils on behaviors, neurotransmitters, liver and kidney functions, biochemical indices, and tissue histological features were studied in Nile tilapia (Oreochromis niloticus) under Ni exposure conditions. A total of 240 fish (27.92 ± 0.22 g) were equally classified into six groups, each with four replicates of 10 fish. The control, MO, and BO groups were fed basal control, 0.1% MO, and 0.1% BO diets, respectively, and reared in Ni-free water. The Ni, Ni + MO, and Ni + BO groups were reared in Ni-medium at a concentration of 3.6 mg/L and fed the same feeding regime as the control, MO, and BO groups, respectively. Ni exposure induced behavioral alterations, including lowered foraging (coefficients of variation, CV = 2.73-14.29%), swimming (CV = 2.95-19.23%), mouth pushing (CV = 9.12-29.37%), spreading of the tail (CV = 3.13-17.32%), and approach (CV = 3.53-11.27%) patterns but increased surfacing (CV = 11.39-23.33%) and resting (CV = 7.14-25%) behaviors. Increased mortality (CV > 30%) and hepato-renal indicators were consequences of Ni exposure. The Ni exposure also depressed brain acetylcholine esterase (AChE) (CV = 0.54-1.10), blood total protein (CV = 3.23-21.87%), albumin (CV = 1.62-13.47%), and globulin (CV = 1.91-24.72%). Histopathological changes were observed in the brain, gills, liver, kidney, and muscle, with detectable Ni residues in the muscle of Nile tilapia. Dietary supplementation with 0.1% MO and/or 0.1% BO significantly improved behavior patterns, blood proteins, and AChE levels under Ni exposure conditions. Hepato-renal indicators and the histology of the studied organs were enhanced, and the residual Ni level was reduced by feeding on the tested diets. Based on the current results, it was concluded that essential oils (0.1% BO and/or 0.1% MO) diets could mitigate the harmful effects caused by Ni exposure in Nile tilapia, which might enhance their future application as effective feed additive candidates in aquaculture.
镍（Ni）作为一种水体金属污染物广泛存在，危害鱼类健康。本研究在尼罗罗非鱼（Oreochromis niloticus）镍暴露条件下，研究了用0.1%互叶白千层（MO）和0.1%罗勒（BO）精油强化饲料对其行为、神经递质、肝脏和肾脏功能、生化指标以及组织组织学特征的影响。总共240条鱼（27.92 ± 0.22克）被平均分为六组，每组10条鱼，设四个重复。对照组、MO组和BO组分别投喂基础对照饲料、含0.1% MO的饲料和含0.1% BO的饲料，并饲养在无镍水中。镍组、镍 + MO组和镍 + BO组饲养在浓度为3.6毫克/升的含镍水体中，分别投喂与对照组、MO组和BO组相同的饲料。镍暴露导致行为改变，包括觅食（变异系数，CV = 2.73 - 14.29%）、游泳（CV = 2.95 - 19.23%）、推嘴（CV = 9.12 - 29.37%）、摆尾（CV = 3.13 - 17.32%）和靠近（CV = 3.53 - 11.27%）行为模式降低，但浮出水面（CV = 11.39 - 23.33%）和静止（CV = 7.14 - 25%）行为增加。镍暴露导致死亡率增加（CV > 30%）和肝肾指标升高。镍暴露还使脑乙酰胆碱酯酶（AChE）（CV = 0.54 - 1.10）、血液总蛋白（CV = 3.23 - 21.87%）、白蛋白（CV = 1.62 - 13.47%）和球蛋白（CV = 1.91 - 24.72%）降低。在脑、鳃、肝脏、肾脏和肌肉中观察到组织病理学变化，尼罗罗非鱼肌肉中可检测到镍残留。在镍暴露条件下，添加0.1% MO和/或0.1% BO的饲料显著改善了行为模式、血液蛋白和AChE水平。通过投喂受试饲料，肝肾指标和所研究器官的组织学得到改善，镍残留水平降低。基于目前的结果，得出结论：精油（0.1% BO和/或0.1% MO）饲料可以减轻尼罗罗非鱼镍暴露造成的有害影响，这可能会增强它们作为水产养殖中有效饲料添加剂候选物的未来应用前景。
