Effects of Eimeria tenella on cecal luminal and mucosal microbiota in broiler chickens

Authors: CAMPOS, PHILLIP - Oak Ridge Institute For Science And Education (ORISE); Miska, Kate; Kahl, Stanislaw; Jenkins, Mark; Shao, Jonathan; Proszkowiec-Weglarz, Monika

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2021
Publication Date: 1/10/2022
Citation: Campos, P., Miska, K.B., Kahl, S., Jenkins, M.C., Shao, J.Y., Proszkowiec-Wegla, M.K. 2022. Effects of Eimeria tenella on cecal luminal and mucosal microbiota in broiler chickens. Avian Diseases. 66(1):1-14. https://doi.org/10.1637/21-00068.
DOI: https://doi.org/10.1637/21-00068

Interpretive Summary: Coccidiosis is one of the most prevalent diseases seen in chickens leading to economic losses in poultry industry. This disease is caused by parasite Eimeria and several species of Eimeria are responsible for coccidiosis in poultry. Each of the species has the ability to infect gut epithelial cells that line the inside of the intestine at specific regions of the gastrointestinal tract. The parasites can cause damage to the intestine, and lead to loss of appetite, decrease in weight gain, increase in feed conversion, diarrhea, and sometimes death. The aim of this study was to evaluate the effect of Eimeria infection on cecal microbiota in chickens. This study utilized modern broiler chickens that at the age of 21 days were infected with Eimeria tenella, that shows infection specificity to ceca. Our results revealed that the Eimeria tenella infection disturbed microbiota balance in both cecal bacterial populations, luminal (inside cecal digesta) and mucosal (bacteria attached to cecal epithelial cells). Additionally, luminal microbiota seemed to be more susceptible to infection caused by Eimeria tenella.

Technical Abstract: The intestinal disease coccidiosis, caused by parasitic Eimeria species, severely impacts poultry production, leading to an estimated $14 billion in annual losses worldwide. As the poultry industry moves away from antibiotics as a treatment for diseases, a better understanding of the microbiota is required to develop other solutions such as probiotics, prebiotics, and nutritional supplements. This study aimed to investigate the effects of Eimeria tenella infection on cecal luminal (contents, CeC) and mucosal (epithelial scrapings, CeS) microbial populations in Ross 708 broiler chickens (288) at multiple time points post-infection (PI). Using 16S rRNA amplicon sequencing, it was revealed that microbial diversity differed in infected (IF) chickens in comparison to the control (C) in both CeC and CeS microbiota at the peak of infection (7 d PI), where simultaneously infected birds saw reduced body weight gain and higher feed conversion ratio. Infection resulted in significant differential abundance of some bacterial taxa, including increases in potential secondary pathogens Escherichia coli, Enterococcus, Clostridium, and Proteus and a decrease in the short chain fatty acid producing family Lachnospiraceae. Predicted metagenomic pathways associated with E. coli, such as those responsible for amino acid biosynthesis, were differentially expressed in IF birds. In conclusion, our results show that E. tenella infection disturbs luminal and mucosal microbiota balance in chickens. Moreover, luminal microbiota seems to be more susceptible to prolonged imbalance due to IF, while mucosal microbiota appeared to be affected only in the short term, demonstrating the importance of researching both the luminal and mucosal microbiota of the cecum.