Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2025
Publication Date: 4/24/2025
Citation: Campos, P.M., Miska, K.B., Jenkins, M.C., Proszkowiec-Wegla, M.K. 2025. Temporal changes in cecal luminal and mucosal microbiota of broiler chickens with clinical coccidiosis (Eimeria maxima). PLOS ONE. https://doi.org/10.1371/journal.pone.0321212 .
DOI: https://doi.org/10.1371/journal.pone.0321212

Interpretive Summary: Broiler (meat) chickens are grown in large numbers to meet the demands of the poultry industry, and these large numbers can be a challenge in preventing the spread of diseases. A disease called coccidiosis involves the infection of the gastrointestinal tract of chickens and is caused by Eimeria parasites, which include at least seven species that infect chickens. The infection can lead to decreased growth rate, diarrhea, loss in appetite, and sometimes even death, causing economic losses. Previously, infections were treated with anti-microbials, but these are no longer in use. The community of bacteria present in the gut, known as the gut microbiome, has been linked to host health, and research in this field may lead to alternative treatments such as probiotics or nutritional supplementation. The goal of this study was to determine changes in bacteria in the cecum (beginning of large intestine) after an infection with Eimeria maxima. Cecum samples were taken at 0, 3, 5, 7, 10, and 14 days after infection, and the populations of bacteria that were present in the cecum contents or were attached to the cecum were analyzed separately. Both populations of bacteria were affected by Eimeria, but the patterns were different. In the cecum contents, bacterial diversity was decreased by infection early in the study (day 3), but diversity was later increased past the peak of infection (day 10). Diversity of bacteria attached to the cecum was increased by infection early (day 5), but then decreased at the end of the study (day 14). We also found that bacteria known for producing short-chain fatty acids such as butyrate could decrease in the infected chickens, which is similar to findings in our previous studies. Butyrate or the bacteria that produce it could be candidates in the future as alternative therapies to anti-microbials because of their potential to limit infection severity and maintain chicken growth rates. More research with other technologies could be carried out to confirm the functions of bacteria found in samples and what effects butyrate and similar molecules have over the course of infection.

Technical Abstract: Coccidiosis is a gastrointestinal disease caused by Eimeria parasites which leads to major economic losses in the poultry industry worldwide. Eimeria infection may impact the gut microbiota, which has been associated with chicken health and performance. This study aimed to determine the effects of Eimeria maxima infection on the luminal and mucosal microbiota of the cecum (CeL and CeM) at multiple time points post-infection (days 3, 5, 7, 10, and 14). Infection decreased Shannon diversity at d 3 (P = 0.03), increased observed features (ASVs) at d 5 (P < 0.01), and increased Shannon diversity at d 10 (P = 0.04) in the CeL microbiota compared to the control. In CeM microbiota, infection increased observed features at d 5 (P = 0.03), but later decreased observed features at d 14 (P = 0.01). Relative abundance of potential butyrate-producing bacteria such as [Ruminococcus] torques group in CeL and Butyricicoccus in CeM were decreased in infected birds, and some metabolic pathways related to butyrate production were predicted to be decreased. These findings show E. maxima may affect cecal microbiota alpha diversity in a time-dependent manner and reduce abundance of bacteria potentially important to gut health.