Plants, plant-derived compounds, probiotics, and postbiotics as green agents to fight against poultry coccidiosis: A review

The intestinal tract is the main place for animals to digest food and absorb nutrients, which also serves as the first line of defense against pathogens that invade the internal environment. Therefore, normal intestinal structure and function are essential for animal health. Poultry coccidiosis is an intestinal disease primarily caused by the parasitization of intestinal epithelial cells by protozoa of the genus Eimeria. The occurrence of coccidiosis not only compromises the intestinal integrity of poultry but also increases their disease susceptibility, thus posing a serious threat to the overall health and productivity of poultry. Nowadays, the primary methods for controlling and preventing coccidiosis in poultry are anticoccidial drugs or live oocyst vaccines. However, the use of the former may be associated with problems of resistance and drug residues, while the use of the latter may cause intestinal damage and significantly increase farming costs. For these reasons, it is critical to investigate green, safe, and cost-effective natural alternative strategies such as phytochemicals and probiotics for controlling coccidiosis as well as mitigating the deleterious effects of coccidial infections in production. In this review, we aim to summarize the role, mechanisms, and therapeutic potential of natural products in the treatment of coccidiosis to lay a theoretical foundation for effective coccidiosis control.