Effect of Acetamizuril on enolase in second-generation merozoites of Eimeria tenella.

As an obligate intracellular apicomplexan parasite, Eimeria tenella (E. tenella) can rapidly invade chicken cecum epithelial cells and cause avian coccidiosis. Enolase, an essential enzyme that catalyzes the reversible conversion of 2-phosphoglycerate into phosphoenolpyruvate, plays a very important role in glycolysis. In this study, each chicken was inoculated with 8×10(4) sporulated E. tenella oocysts suspended in 1ml of distilled water to determine the effects of acetamizuril, a new triazine anticoccidial drug, on enolase in the second-generation merozoites of E. tenella. The chickens were divided into two groups: the untreatment group (challenged with E. tenella oocysts and provided with normal feed) and the treatment group (challenged with E. tenella oocysts and provided with 5mg/kg of acetamizuril by oral gavage at 96h after inoculation). The second-generation merozoites of E. tenella (mz-En) were obtained at 120h after inoculation. Subsequently, quantitative real-time PCR and Western blotting were conducted to detect the enolase changes in mz-En at the transcriptional and translational levels. The results showed that enolase mRNA expression was downregulated, and the translational level was decreased in the treatment group. In addition, the subcellular localization of enolase demonstrated that enolase was distributed primarily at the top of the mz-En and that the fluorescence intensity was weak after treatment with acetamizuril. These findings indicated that enolase may be a promising target to prevent coccidiosis.