Aquaculture Research Institute, Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID, 83844, USA.
Department of Aquaculture and Fisheries, University of Arkansas at Pine Bluff, 1200 North University Drive, Pine Bluff, 71601, AR, USA.
Ecotoxicol Environ Saf. 2020 Dec 1;205:111337. doi: 10.1016/j.ecoenv.2020.111337. Epub 2020 Sep 23.
Iron overload in water is a problem in many areas of the world, which could exert toxic effects on fish. To achieve maximum growth and overall fitness, iron induced toxicity must be alleviated. Therefore, this research was undertaken to investigate the potential mitigation of iron toxicity by dietary vitamin C supplementation in channel catfish (Ictalurus punctatus). Two doses of vitamin C (143 and 573 mg/kg diet) were tested against high environmental iron (HEI, 9.5 mg/L representing 25% of 96 h LC). Fish were randomly divided into six groups with four replicated tanks. The groups were Control (vitamin C deficient feed), LVc (143 mg vitamin C supplemented per kg diet), HVc (573 mg vitamin C supplemented per kg diet), Con + Fe (control exposed to HEI), LVc + Fe (LVc exposed to HEI) and HVc + Fe (HVc exposed to HEI). Following an 8 week trial, there was a significant reduction in weight gain (WG%) in Con + Fe compared to the control, indicating a toxic effect of HEI on fish growth performance. Interestingly, WG% in both LVc + Fe and HVc + Fe groups were significantly higher than Cont + Fe, signifying that HEI inhibited growth, but this was alleviated by vitamin C. Both hemoglobin content and hematocrit were higher in LVc + Fe compared to the control and Con + Fe. In addition, exposure to HEI (Con + Fe) incited hepatic oxidative stress based on an over-accumulation of malondialdehyde (MDA) along with a significant inhibition in superoxide dismutase (SOD) and catalase (CAT) activities; whereas in LVc + Fe and HVc + Fe, the MDA content restored to basal level. A series of histopathological alterations were observed in the liver and gills, with the most severe lesions in Con + Fe, which was also complemented with a remarkable increase in hepatic iron accumulation. Vitamin C supplementations reduced the augmented concentrations of iron accumulation to that of the control. No effect, regardless of the treatments, was noted for fatty acid composition of muscle. Overall, our findings suggest that the vitamin C supplementation can be an effective therapeutic approach for boosting growth as well as alleviating iron toxicity in catfish.
水中的铁过载是世界上许多地区的一个问题，它可能对鱼类产生毒性影响。为了实现最大的生长和整体健康，必须减轻铁诱导的毒性。因此，这项研究旨在探讨通过膳食维生素 C 补充来减轻虹鳟（Ictalurus punctatus）中铁毒性的潜力。测试了两种维生素 C 剂量（饲料中 143 和 573mg/kg）对抗高环境铁（HEI，9.5mg/L 代表 96hLC 的 25%）的效果。鱼被随机分成六组，每组四个重复水槽。这些组分别为对照（缺乏维生素 C 的饲料）、LVc（每公斤饲料补充 143mg 维生素 C）、HVc（每公斤饲料补充 573mg 维生素 C）、Con+Fe（对照暴露于 HEI）、LVc+Fe（LVc 暴露于 HEI）和 Hvc+Fe（HVc 暴露于 HEI）。经过 8 周的试验，与对照组相比，Con+Fe 组的体重增加（WG%）显著降低，表明 HEI 对鱼类生长性能有毒性作用。有趣的是，LVc+Fe 和 Hvc+Fe 组的 WG%均显著高于 Cont+Fe，表明 HEI 抑制了生长，但这可以通过维生素 C 来缓解。与对照组和 Cont+Fe 相比，LVc+Fe 中的血红蛋白含量和血细胞比容更高。此外，暴露于 HEI（Con+Fe）会引起肝氧化应激，表现为丙二醛（MDA）过度积累，同时超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性受到显著抑制；而在 Lvc+Fe 和 Hvc+Fe 中，MDA 含量恢复到基础水平。肝脏和鳃中观察到一系列组织病理学改变，在 Con+Fe 中观察到最严重的病变，同时肝铁积累显著增加。维生素 C 补充降低了肝铁积累的增加浓度，使其恢复到对照水平。无论处理方式如何，肌肉脂肪酸组成都没有受到影响。总的来说，我们的研究结果表明，维生素 C 补充可以是一种有效的治疗方法，既能促进生长，又能减轻虹鳟的铁毒性。
