<abstract xmlns="http://www.w3.org/1999/xhtml">

<p><italic>Clarias gariepinus</italic> is one of the widespread culturable freshwater fish species in Africa, which is prevalent in various natural and human-made aquatic habitats including rice-fish system. This fish species displays predation potential on the aquatic stages of mosquitoes. Bensulfuron-methyl and quinclorac are herbicide active substances that have been extensively applied in rice culture in Egypt and other countries worldwide. This study assessed the adverse effects of sublethal concentration of a commercial herbicide formulation containing quinclorac and bensulfuron-methyl on the predation potential of <italic>C. gariepinus</italic> female and male predatory fish on <italic>Culex pipiens</italic> mosquito larvae. Also, stomach and intestine histopathology of the treated fish was investigated. The exposure of <italic>C. gariepinus</italic> to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide produced detrimental effects on prey consumption and histopathological changes in the stomach and intestine of the fish. The mosquito consumption by the treated female and male fish decreased significantly compared to the untreated fish of both sexes. The histological changes in the intestines were hyperplasia of the intestinal epithelium and goblet cells; edema of lamina propria and broad intestinal villi, and distortion in intestinal villi in comparison to control. The stomach histopathology changes were necrosis and sloughing of mucosal epithelium with severe damage of sub-mucosa. Thus, the tested herbicide at sublethal concentration on <italic>C. gariepinus</italic> decreased the prey consumption on mosquito larvae and caused histopathological alterations in the fish that may impair its digestive physiology. These findings suggest a threat of the tested herbicide to <italic>C. gariepinus</italic> survival and potential as a native successful biocontrol agent against <italic>Cx. pipiens</italic> larvae.</p>
</abstract>

Clarias gariepinus is one of the widespread culturable freshwater fish species in Africa, which is prevalent in various natural and human-made aquatic habitats including rice-fish system. This fish species displays predation potential on the aquatic stages of mosquitoes. Bensulfuron-methyl and quinclorac are herbicide active substances that have been extensively applied in rice culture in Egypt and other countries worldwide. This study assessed the adverse effects of sublethal concentration of a commercial herbicide formulation containing quinclorac and bensulfuron-methyl on the predation potential of C. gariepinus female and male predatory fish on Culex pipiens mosquito larvae. Also, stomach and intestine histopathology of the treated fish was investigated. The exposure of C. gariepinus to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide produced detrimental effects on prey consumption and histopathological changes in the stomach and intestine of the fish. The mosquito consumption by the treated female and male fish decreased significantly compared to the untreated fish of both sexes. The histological changes in the intestines were hyperplasia of the intestinal epithelium and goblet cells; edema of lamina propria and broad intestinal villi, and distortion in intestinal villi in comparison to control. The stomach histopathology changes were necrosis and sloughing of mucosal epithelium with severe damage of sub-mucosa. Thus, the tested herbicide at sublethal concentration on C. gariepinus decreased the prey consumption on mosquito larvae and caused histopathological alterations in the fish that may impair its digestive physiology. These findings suggest a threat of the tested herbicide to C. gariepinus survival and potential as a native successful biocontrol agent against Cx. pipiens larvae.

Behavioral and histopathological changes of <italic>Clarias gariepinus</italic> as a predatory fish against <italic>Culex pipiens</italic> larvae following exposure to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide

Plant Protection Department, Faculty of Agriculture

Pathology Department, Faculty of Veterinary Medicine

Fish Diseases and Management Department, Faculty of Veterinary Medicine

Hellenic Plant Protection Journal

This work is licensed under the Creative Commons Attribution 4.0 International License.

Behavioral and histopathological changes of  as a predatory fish against  larvae following exposure to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide

Clarias gariepinus is one of the widespread culturable freshwater fish species in Africa, which is prevalent in various natural and human-made aquatic habitats...

Behavioral and histopathological changes of Clarias gariepinus as a predatory fish against Culex pipiens larvae following exposure to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide

Published Online: Jul 16, 2023

Page range: 67 - 78

Received: Sep 27, 2022

Accepted: Jun 18, 2023

DOI: https://doi.org/10.2478/hppj-2023-0009

Keywords
herbicide, histopathology, predatory fish, prey

© 2023 I.A. Mohamed et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Behavioral and histopathological changes of Clarias gariepinus as a predatory fish against Culex pipiens larvae following exposure to sublethal concentration of quinclorac and bensulfuron-methyl based herbicide

Published Online: Jul 16, 2023

Page range: 67 - 78

Received: Sep 27, 2022

Accepted: Jun 18, 2023

DOI: https://doi.org/10.2478/hppj-2023-0009

Keywordsherbicide, histopathology, predatory fish, prey

© 2023 I.A. Mohamed et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
herbicide, histopathology, predatory fish, prey