Sophora flavescens seed reinforces chicken cecal barrier against Eimeria tenella

Eimeria tenella (E. tenella) causes severe coccidiosis in chickens, leading to bloody diarrhea, growth retardation, high mortality, and substantial economic losses. Rising drug resistance and residue concerns limit conventional chemical anticoccidials, driving interest in Traditional Chinese Medicine as a safe, cost-effective, and sustainable alternative. To investigate the effects of Sophora flavescens seed extract (SFSE) on E. tenella-infected chicken ceca, 12-day-old chickens were assigned to control, infection, and SFSE groups, with the latter two orally inoculated with sporulated E. tenella oocysts on day 14. Samples were collected at 5- and 7-days post-infection (DPI). Cecal histopathology was assessed with HE and Masson's trichrome staining. DNA damage was detected by TUNEL assay. Goblet cell distribution and glycoprotein composition were evaluated using PAS and AB-PAS staining, respectively. Apoptosis-related proteins, mucins, and cell junction proteins were analyzed via immunofluorescence. Myosin light chain kinase (MLCK) expression was examined via immunohistochemistry analysis. Parameters including relative weight gain, survival rate, oocyst value, cecal lesion score, and anticoccidial index (ACI) were assessed. SFSE treatment improved growth performance, alleviated cecal tissue damage and fibrosis, and yielded an ACI value of 126.26. SFSE reduced Caspase-3 expression and elevated the Bcl-2/Bax ratio. Furthermore, SFSE enhanced intestinal mucosal barrier function by increasing goblet cell counts, glycoprotein expression, and MUC2 and TFF3 secretion. The expression of tight junction proteins Occludin, ZO-1, E-cadherin, and Desmoplakin was upregulated, whereas Claudin-2 and MLCK were downregulated. Collectively, SFSE treatment showed partial anticoccidial efficacy by alleviating cecal damage and apoptosis, increasing goblet cell numbers and mucin secretion, and downregulating MLCK to restore tight junction proteins, thereby improving intestinal barrier function. This study provides a scientific basis for using traditional Chinese medicine in preventing and treating avian coccidiosis, with significant clinical relevance.