Glyphosate-induced biochemical changes in female Cynopoecilus sp. inhabiting temporary wetlands

Glyphosate is Brazil’s most widely used pesticide, often applied to different crops that may be close to temporary wetlands. This pesticide poses a threat to populations of annual killifish that live in these locations. Few studies have explored the toxicodynamics of pesticides in annual killifish. Here females of Cynopoecilus sp. at different development stages (young-adult and senile) are exposed to Roundup Original DI® herbicide (65, 130 and 260 µg/L of acid equivalent of N-phosphomethyl glycine (glyphosate)) to analyze its impact on oxidative balance and lipoperoxidation, including superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and SOD/CAT ratio, as well as markers of intermediary metabolism such as total proteins (TPs), glycogen, and uric acid (UA). Senile females showed increased CAT and glutathione S-transferase activities and a decreased SOD/CAT ratio. Total protein and UA values were increased. Two-way ANOVA demonstrated correlations between age and different exposure groups for lipoperoxidation, SOD, CAT, GST, TPs, and UA, especially in senile females. Although it is not considered a target species, Cynopoecilus sp. suffers harmful effects from the interaction with this herbicide even at environmentally relevant concentrations. This impact was observed in senile females, which may result in reduced life cycle and reproduction quality. Exposure to Roundup Original® herbicide does not cause lipoperoxidation in females. Glyphosate-based herbicide exposure modulated oxidative balance markers. Herbicide exposure caused changes in the metabolism (total proteins (TPs) and uric acid) of young adults. The herbicide caused changes in energy markers (glycogen and TPs) in senile females. Senile females were more vulnerable to the glyphosate-based herbicide.

草甘膦是巴西使用最为广泛的农药，常被施用于邻近临时湿地的各类农作物。该农药对栖息于此的一年生鳉鱼种群构成威胁。目前鲜有研究针对一年生鳉鱼开展农药毒效动力学相关探索。本研究以不同发育阶段（青年-成年及老年）的辛普逊鳉（Cynopoecilus sp.）雌性个体为实验对象，使用农达原剂型DI®（Roundup Original DI®）除草剂进行暴露处理，其草甘膦酸当量浓度分别为65、130及260 µg/L（有效成分为N-膦酰甲基甘氨酸，即草甘膦），旨在分析该除草剂对氧化平衡与脂质过氧化的影响。检测指标包括超氧化物歧化酶（superoxide dismutase, SOD）、过氧化氢酶（catalase, CAT）、谷胱甘肽S-转移酶（glutathione S-transferase, GST）及SOD/CAT比值，同时检测中间代谢标志物，如总蛋白（total proteins, TPs）、糖原与尿酸（uric acid, UA）。老年雌性个体的CAT与GST活性显著升高，SOD/CAT比值降低；总蛋白与UA水平亦显著上升。双因素方差分析（two-way ANOVA）结果显示，脂质过氧化水平、SOD、CAT、GST、TPs及UA均与年龄及暴露组别存在显著关联，该关联在老年雌性个体中尤为显著。尽管辛普逊鳉（Cynopoecilus sp.）并非该除草剂的靶标物种，但即便处于环境相关浓度下，其仍会因接触该除草剂而受到有害影响。该有害影响在老年雌性个体中表现最为明显，可能会缩短其生命周期并降低繁殖质量。暴露于农达原剂型®（Roundup Original®）除草剂并不会导致雌性个体发生脂质过氧化。草甘膦类除草剂暴露可调控氧化平衡相关标志物的表达水平。除草剂暴露会改变青年-成年个体的代谢指标（总蛋白TPs与尿酸UA）。该除草剂会改变老年雌性个体的能量代谢标志物（糖原与总蛋白TPs）水平。老年雌性个体对草甘膦类除草剂的敏感性更强。