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）对革胡子鲶（Clarias gariepinus）的亚致死效应，重点分析其血液学、生化及氧化应激指标的变化。将幼龄革胡子鲶暴露于浓度分别为1.80、3.50和7.10 mg/L的FPB溶液中，上述浓度分别对应该物质96小时半致死浓度（96h LC₅₀）的5%、10%和20%，暴露周期为21天，随后设置7天的恢复期。采集受试鱼的血液、肝脏及鳃组织进行检测分析。结果显示，不同FPB暴露浓度组的幼鲶红细胞比容、血红蛋白含量及红细胞计数均显著下降，而白细胞计数呈上升趋势。其中中性粒细胞计数升高，淋巴细胞计数降低，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转氨酶、丙氨酸转氨酶及碱性磷酸酶活性较对照组显著升高。葡萄糖含量在各组间呈现混合变化趋势，但两种组织中的总蛋白含量均有所降低。受试鱼肝脏与鳃组织中超氧化物歧化酶、过氧化氢酶及谷胱甘肽过氧化物酶活性显著下降，而丙二醛、总谷胱甘肽及谷胱甘肽还原酶含量均升高。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对幼龄革胡子鲶具有毒性，长期暴露可能对水生生物造成严重健康风险，因此该药剂需谨慎使用。