Anticoccidial activity and its potential Mechanisms of Stemona tuberosa against Eimeria tenella: In Vivo and In Vitro Investigations and Host Intestinal Protection.

Coccidiosis causes substantial economic losses in poultry, and current control relies largely on chemotherapeutics. Plant-derived extracts offer low toxicity, environmental safety, and reduced resistance risks. This study evaluated the anticoccidial activity of Stemona tuberosa ethanol extract (STEE) and explored its underlying mechanisms. Anticoccidial efficacy was assessed through oocyst sporulation, sporozoite invasion, anticoccidial index (ACI), hematological parameters, inflammatory markers, and intestinal protective proteins. Mechanistic analyses included 16S rRNA sequencing and western blotting. In vitro, 1 mg/mL STEE inhibited oocyst sporulation by 66.5% and invasion by 62.72%. In vivo, high-dose STEE yielded a 92.52% relative weight gain, 100% survival, and an ACI of 164.23. STEE improved intestinal barrier integrity by increasing occludin and tight junction protein-1 expression by 48.85% and 53.76%, respectively. Gut microbiota analysis showed restoration of caecal microbial diversity and correction of coccidia-induced metabolic disturbances. The further study showed that STEE reduced inflammation repsonse induced by Eimeria tenella via downregulating the TLR2/NFκB pathway. These findings support STEE as a promising phytotherapeutic candidate for controlling avian coccidiosis.