Therapeutic effect of a self-made herbal formula on a multi-drug resistant Eimeria tenella isolate infection in broiler chickens

In-feed prophylactic chemotherapy is widely considered the mainstay of avian coccidiosis control, while serious drug resistance strictly restricts its application. Confronted with the urgent need for an alternative strategy, a traditional Chinese medicine formula (TCMF) was developed. Meanwhile, its potential to iron out complicated clinical coccidiosis was scrutinized in vivo with a field-isolated multi-drug resistant Eimeria tenella (E. tenella) isolate. Birds were inoculated with 5 × 104 sporulated oocysts and administrated with TCMF supplementation in water from 72 h post-infection to the end of the experiment, diclazuril (DIC) was set as a positive control. As a result, TCMF intervention reduced oocyst shedding, cecal lesion and mortality, and enhanced body weight gain. According to the above, anticoccidial index (ACI) was calculated and TCMF exerted a moderate anticoccidial activity. Besides, macroscopic, histopathological, and ultrastructural observations revealed the safeguarding effects of TCMF on E. tenella-induced cecal injury. Following, TCMF treatment presented an obvious inhibition effect on E. tenella caused oxidative stress and inflammatory response. Moreover, TCMF supplementation restored the cecal flora abundance and diversity, reduced the colonization of harmful bacteria, and increased the probiotics abundance. In conclusion, TCMF exhibited a moderate anticoccidial effect along with alleviating E. tenella-induced cecal injury, redox imbalance, and inflammatory response which may be associated with the microflora modulatory effect.