背景:包括杀真菌剂在内的农药的不当使用会造成严重的生物危害,从而危害鱼类健康并阻碍可持续的水产养殖。
目的:本研究调查了美替拉姆(MET)的负面影响,作为静态更新系统中的急性暴露,对尼罗罗非鱼(Oreochromisniloticus)的健康状况持续96小时。
方法:将三百条鱼(平均体重:37.50±0.22g)分为六组(50条鱼/组),重复五次(10条鱼/重复)。鱼暴露于不同浓度(0、1.5、3、4.5、6和7.5mg/L)的MET中,作为水暴露96小时,没有水交换。鱼的行为,临床体征,和死亡率记录在暴露期的每一天。此外,MET对血液特征的影响,压力生物标志物,肝肾功能,免疫-抗氧化状态,和大脑生物标志物被密切监测。
结果:使用Finney的probit技术估算的MET的致死浓度(LC50)为3.77mg/L。鱼的行为受到急性MET暴露的严重影响,从堆焊的增加可以看出,失去平衡,不寻常的游泳,偏侧性,异常运动,攻击性行为的下降。生存能力和血液学指标(白细胞和红细胞计数,白细胞分类计数,血细胞比容值,和血红蛋白)在MET暴露后以浓度依赖性方式显着降低。急性暴露于MET(1.5-7.5mg/L)逐渐增加的应激生物标志物(去甲肾上腺素,皮质醇,和葡萄糖),脂质过氧化物(丙二醛),和脑氧化DNA损伤生物标志物(8-羟基-2-脱氧鸟苷)。丙氨酸和天冬氨酸转氨酶和肌酐值的显着增加证明了MET暴露(4.5-7.5mg/L)导致的肝肾功能障碍。此外,免疫参数的大幅下降(溶菌酶,补体3,血清杀菌活性,和抗蛋白酶活性)和抗氧化变量(总抗氧化能力,超氧化物歧化酶,和谷胱甘肽过氧化物酶)是由急性MET暴露引起的。
结论:根据这些发现,尼罗罗非鱼MET的96小时LC50为3.77mg/L。MET暴露引发尼罗罗非鱼的毒性,从鱼类神经行为的改变可以看出,免疫-抗氧化状态,肝肾功能,表示生理紊乱。这项研究强调了MET作为水生系统的环境污染物引起的潜在生态危险。然而,长期MET暴露仍需要调查。
BACKGROUND: The inappropriate use of pesticides including fungicides creates severe biological hazards that can endanger fish health and impede sustainable aquaculture.
OBJECTIVE: This study investigated the negative impacts of metiram (MET), a fungicide on the health status of Nile tilapia (Oreochromis niloticus) for a 96-hour duration as an acute exposure in a static renewal system.
METHODS: Three hundred fish (average body weight: 37.50 ± 0.22 g) were assigned into six groups (50 fish/group) with five replicates (10 fish/replicate). Fish were exposed to various six concentrations (0, 1.5, 3, 4.5, 6, and 7.5 mg/L) of MET as a water exposure to for 96-hour without water exchange. The fish\'s behavior, clinical signs, and mortalities were documented every day of the exposure period. Additionally, MET\'s impact on blood profile, stress biomarkers, hepato-renal functions, immune-antioxidant status, and brain biomarker were closely monitored.
RESULTS: The lethal concentration (LC50) of MET estimated using Finney\'s probit technique was 3.77 mg/L. The fish\'s behavior was severely impacted by acute MET exposure, as clear by an increase in surfacing, loss of equilibrium, unusual swimming, laterality, abnormal movement, and a decline in aggressive behaviors. The survivability and hematological indices (white and red blood cell count, differential white blood cell count, hematocrit value, and hemoglobin) were significantly reduced in a concentration-dependent manner following MET exposure. Acute exposure to MET (1.5-7.5 mg/L) incrementally increased stress biomarkers (nor-epinephrine, cortisol, and glucose), lipid peroxides (malondialdehyde), and brain oxidative DNA damage biomarker (8-hydroxy-2-deoxyguanosine). A hepato-renal dysfunction by MET exposure (4.5-7.5 mg/L) was evidenced by the significant increase in the alanine and aspartate aminotransferases and creatinine values. Moreover, a substantial decline in the immune parameters (lysozyme, complement 3, serum bactericidal activity, and antiprotease activity) and antioxidant variables (total antioxidant capacity, superoxide dismutase, and glutathione peroxidase) resulted from acute MET exposure.
CONCLUSIONS: According to these findings, the 96-hour LC50 of MET in Nile tilapia was 3.77 mg/L. MET exposure triggered toxicity in Nile tilapia, as seen by alterations in fish neuro-behaviors, immune-antioxidant status, hepato-renal functioning, and signifying physiological disturbances. This study emphasizes the potential ecological dangers provoked by MET as an environmental contaminant to aquatic systems. However, the long-term MET exposure is still needed to be investigated.