Effects of Eimeria acervulina infection on the luminal and mucosal microbiota of the cecum and ileum in broiler chickens

Authors: Campos, Philip; Miska, Kate; Jenkins, Mark; Yan, Xianghe; Proszkowiec-Weglarz, Monika

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2024
Publication Date: 5/10/2024
Citation: Campos, P.M., Miska, K.B., Jenkins, M.C., Yan, X., Proszkowiec-Wegla, M.K. 2024. Effects of Eimeria acervulina infection on the luminal and mucosal microbiota of the cecum and ileum in broiler chickens. Scientific Reports. 14: 10702. https://doi.org/10.1038/s41598-024-61299-6.
DOI: https://doi.org/10.1038/s41598-024-61299-6

Interpretive Summary: Chickens provide a nutritious and relatively inexpensive source of meat and are grown intensively in large numbers to meet the demands of an expanding poultry industry. These large numbers cause challenges in preventing the spread of diseases caused by microorganisms. A group of parasites known as Eimeria contains several species which infect the gastrointestinal tract of chickens and causes the disease coccidiosis. Coccidiosis can result in decrease in weight, diarrhea, loss in appetite, and sometimes even death, reducing the profits of poultry farmers. In the past, coccidiosis was treated primarily with anti-microbials, however, these are no longer in use. Alternative solutions to treat infections could include methods that make use of knowledge of the gut microbiome (bacterial species), such as probiotics or nutritional supplementation, therefore we have researched the effects of coccidiosis on the gut microbiome. In this study, chickens were infected with Eimeria acervulina, and parts of the lower small intestine (ileum) and beginning of the large intestine (cecum) were taken at six time points for microbiome analysis. Populations of bacteria that were attached to the gut or were present in the gut contents were analyzed separately. The infection had effects on both bacteria attached to the gut and bacteria in the gut contents in the cecum, while in the ileum, only the bacteria in the gut contents were affected. The type of effect and timing of effect (before or after the peak infection period of seven days) differed depending on where the bacteria was obtained from. Another finding was that certain bacteria that can possibly make and secrete short chain fatty acids can be decreased during the Eimeria infection. Short chain fatty acids are very important molecules because they have anti-inflammatory properties and have been shown to reduce the severity of Eimeria infection. By decreasing the bacteria that produce short chain fatty acids, it is possible the Eimeria infection has more severe effects on chicken health. These small molecules might be an option for an alternative therapy to anti-microbials, however, more research needs to be carried out to confirm the functions of these bacteria and what effects short chain fatty acids have over the course of infection.

Technical Abstract: Coccidiosis, an intestinal disease caused by Eimeria parasites, is responsible for major losses in the poultry industry by impacting chicken health. The gut microbiota is associated with health factors, such as nutrient exchange and immune system modulation. Active research is being applied to understand the effects of Eimeria infection on the gut microbiota. This study aimed to determine the effect of Eimeria acervulina infection on the luminal and mucosal microbiota of both the cecum (CeL and CeM) and ileum (IlL and IlM) at multiple time points (days 3, 5, 7, 10, and 14) post-infection. E. acervulina infection affected alpha and beta diversity in CeL, CeM, and IlL microbiota at varying time points, with more prolonged effects in IlL microbiota (d 3 to 10). Bacterial taxa known for short-chain fatty acid (SCFA) production were reduced in relative abundance in infected birds compared to control birds in CeL, CeM, and IlL microbiota. Based on predicted functional abundances, metabolic pathways related to production of an important SCFA, butyrate, may be impacted. Our findings contribute to our understanding of the effects of Eimeria acervulina alone on the cecal and ileal microbiota and may lead to further research investigating metabolic function of GIT bacteria.