Target epidermal damage of Gyrodactylus kobayashii to obtain the effective anthelmintic compound glacial acetic acid

Gyrodactylosis causes fish to be infected by other harmful pathogens, resulting in high mortality rates and serious economic losses to the aquaculture industry. Currently, unapproved chemicals are the main reliance for gyrodactylosis treatment, which is not always satisfactory. Targeted selection of compounds that destroy the epidermal structure of the parasite becomes an ideal strategy for parasites control. Therefore, glacial acetic acid (GAA) was found to have the ability to corrode the body surface of the parasite and thus achieve an antiparasitic effect. Next, we evaluated the anthelmintic activity of GAA, the maximum anthelmintic activity of 0.005% GAA for 48 h was 89%, and 0.01% GAA completely killed all Gyrodactylus kobayashii in 40 min. Further research involved evaluating water quality parameters and mRNA expression patterns of xenobiotics sensitive genes, ultimately selecting the treatment method of 0.01% for 40 min followed by transferring the goldfish to normal water for further study. In vitro experiments and scanning electron microscopy results revealed that GAA inhibits parasite activity and ultimately leads to parasite death by disrupting the structure of the parasite's body surface. Overall, these findings suggest that GAA could be a promising alternative compound for controlling Gyrodactylus infections and targeted disruption of the worm's body surface structure is an effective strategy for eliminating the parasite.