The Center for Applied Research on the Environment and Sustainability, The American University in Cairo, Cairo, 11835, Egypt.
Animal Production Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, 33516, Egypt.
Environ Sci Pollut Res Int. 2022 Aug;29(37):56357-56369. doi: 10.1007/s11356-022-19702-0. Epub 2022 Mar 25.
African catfish is a freshwater species with a high ability to resist brackish water conditions, but heat stress may impair the health status of fish. Thus, the impact of varying levels of water salinity (0, 4, 8, and 12 ppt) was investigated on the growth performance, survival rate, and blood biochemistry of African catfish (average weight: 180.58 ± 2.8 g and average length: 38 ± 1.2 cm) for 4 weeks; then, fish were stressed with high temperature (32 °C) for 72 h. The growth performance and survival rate were markedly higher in fish reared in 0, 4, and 8 ppt than fish in 12 ppt (p < 0.05). Before heat stress, the superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) activities, and malondialdehyde (MDA) levels were markedly increased in fish stressed with 12-ppt salinity (p < 0.05). After heat stress, all groups showed a marked increased SOD, CAT, GSH, and MDA levels than fish before heat stress in the same manner (p < 0.05). Furthermore, fish in the 12 ppt group showed severe intestinal, gill, and liver histological features. The levels of blood glucose and cortisol were markedly increased in fish exposed with 8 and 12 ppt than 0 ppt gradually either before or after heat stress (p < 0.05). The highest values of ALT, AST, urea, creatinine, and the lowest total protein, albumin, and globulin were observed in fish reared in 12 ppt. Significant salinity and heat stress interactions were seen on the ALT, AST, urea, creatinine, total protein, albumin, and globulin values (p < 0.05). The integrated multi-biomarker response (IBR) results showed marked differences among the groups and increased gradually before and after heat stress, with the highest IBR in 12 ppt. In conclusion, growing African catfish in high salinity (12 ppt) hampered the growth performance and health status while the heat stress improved the antioxidative status vis-a-vis increased lipid peroxidation along with higher stress-related markers in expressed both blood and tissue.
非洲鲶鱼是一种具有高耐盐能力的淡水物种，但热应激可能会损害鱼类的健康状况。因此，本研究调查了不同盐度水平（0、4、8 和 12 ppt）对非洲鲶鱼（平均体重：180.58 ± 2.8 g，平均长度：38 ± 1.2 cm）生长性能、存活率和血液生化指标的影响，为期 4 周；然后，将鱼在高温（32°C）下应激 72 h。在 0、4 和 8 ppt 中饲养的鱼的生长性能和存活率明显高于在 12 ppt 中的鱼（p < 0.05）。在热应激之前，在盐度为 12 ppt 应激的鱼中，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽（GSH）活性和丙二醛（MDA）水平显著升高（p < 0.05）。热应激后，所有组的 SOD、CAT、GSH 和 MDA 水平均高于热应激前同一组的水平（p < 0.05）。此外，在 12 ppt 组中，鱼表现出严重的肠道、鳃和肝脏组织学特征。在热应激之前或之后，暴露于 8 和 12 ppt 的鱼的血糖和皮质醇水平均明显高于 0 ppt（p < 0.05）。在 12 ppt 中饲养的鱼的 ALT、AST、尿素、肌酐以及总蛋白、白蛋白和球蛋白的最低值最高。在 ALT、AST、尿素、肌酐、总蛋白、白蛋白和球蛋白值方面观察到显著的盐度和热应激相互作用（p < 0.05）。综合多生物标志物反应（IBR）结果表明，各组之间存在明显差异，并且在热应激前后逐渐增加，12 ppt 组的 IBR 最高。总之，在高盐度（12 ppt）中养殖非洲鲶鱼会阻碍其生长性能和健康状况，而热应激会改善抗氧化状态，同时增加脂质过氧化作用以及血液和组织中更高的应激相关标志物。
