Efficacy of glacial acetic acid in the control of Trichodina sp. and Apiosoma sp. associated with Mugil liza

Abstract This study evaluated whether glacial acetic acid can control ciliate infestation of Trichodina sp. and Apiosoma sp. on juveniles of Mugil liza . A total of 84 juvenile mullets (11.52 ± 1.23 g, 8.72 ± 0.94 cm) kept in twelve 80 L tanks (useful volume of 45 L each) were used. The acetic acid concentrations tested were 0 (T0), 238 (T1), 476 (T2), and 715 (T3) mg L − 1 , with three replicates of seven fish each. The experimental procedure consisted of 1 h of parasiticidal bath, followed by 2 h of recovery. Following the recovery period, the fish were individually euthanized, and the left and right sides of the body were scraped in the anteroposterior direction. Biometry followed the scraping of the first branchial arch (both left and right sides). The scrapes were set on slides and either stained with silver nitrate or fixed with methanol and stained with Giemsa. Trichodina sp. and Apiosoma sp. were found infesting 100% of the gills and integument of the T0 fish. The efficacy of acetic acid to control Trichodina sp. was high in all treatments (in gills, 71.43% [T1], 95.51% [T2], and 99.20% [T3]; for integument, 64.39% [T1], 99.75% [T2], and 99.97% [T3]). The efficacy of acetic acid to control Apiosoma sp. was also high (in gills, 99.43% [T1], 98.04% [T2], and 99.52% [T3]; for integument, 95.83% [T1], 98.9% [T2], and 99.12% [T3]). Based on our findings, glacial acetic acid concentration of 238 mg L − 1 is effective against Apiosoma sp. and concentration of 476 mg L − 1 is effective against Trichodina sp.