Long term integrated biomarker responses in freshwater African catfish <i>Clarias gariepinus</i> exposed to a new brand of herbicide fluazifop-p-butyl

The study investigated the sublethal effects of Fluazifop-p-butyl <b>(</b>FPB) on the haematological, biochemical and oxidative stress changes in <i>Clarias gariepinus.</i> Juvenile <i>C. gariepinus</i> were exposed to FPB concentrations of 1.80, 3.50, and 7.10 mg/l corresponding to 5, 10 and 20% of 96 h LC₅₀ value of FPB respectively for 21 days and allowed to recover for 7 days. The blood, liver and gills were removed and analyzed. Fish exposed to different concentrations of FPB showed significant decline in the values the pack cell volume, hemoglobin and red blood cells but the white blood cell values increased. The neutrophil values increased while the lymphocyte declined but the monocytes, basophil and eosinophil values remain unchanged. The liver and gill aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase significantly increased compared to the control. There were mixed trends in the values of glucose but total protein was reduced in both tissues of the fish. There was significant decline in superoxide dismutase, catalase and glutathione peroxidase while malondialdehyde, total glutathione, and glutathione reductase increased in both liver and gill of the exposed fish. Following the 7-day withdrawal, most of the observed parameters returned to normal values. The present study revealed that FPB is toxic to <i>C. gariepinus</i> juveniles and prolonged exposure could result to major health risks to aquatic organisms, hence, they should be carefully used.本研究探讨了精吡氟禾草灵（Fluazifop-p-butyl，FPB）对革胡子鲇（Clarias gariepinus）血液学、生物化学指标及氧化应激变化的亚致死效应。将幼龄革胡子鲇暴露于浓度分别为1.80、3.50和7.10 mg/L的FPB溶液中，对应其96小时半数致死浓度（96 h LC₅₀）的5%、10%和20%，暴露时长为21天，随后进行7天的恢复实验。采集血液、肝脏及鳃组织进行分析检测。结果显示，不同FPB暴露浓度下，受试鱼的红细胞压积、血红蛋白含量及红细胞计数均显著下降，而白细胞计数则升高。其中中性粒细胞计数上升，淋巴细胞计数下降，但单核细胞、嗜碱性粒细胞及嗜酸性粒细胞计数无明显变化。肝脏与鳃组织中的天冬氨酸氨基转移酶、丙氨酸氨基转移酶及碱性磷酸酶活性均较对照组显著升高。血糖水平呈现混合变化趋势，但受试鱼两种组织中的总蛋白含量均有所降低。超氧化物歧化酶、过氧化氢酶及谷胱甘肽过氧化物酶活性显著下降，而暴露组鱼肝脏与鳃组织中的丙二醛、总谷胱甘肽及谷胱甘肽还原酶活性均有所升高。经过7天的停药恢复后，绝大多数观测指标均恢复至正常水平。本研究表明，FPB对革胡子鲇幼鱼具有毒性，长期暴露可能对水生生物造成严重健康风险，因此需谨慎使用该药剂。