Comparison of the caecal microbial community structure and physiological indicators of healthy and infection Eimeria tenella chickens during peak of oocyst shedding

ABSTRACT

Eimeria tenella (E. tenella), an important intestinal parasite of chicken caeca, causes coccidiosis and brings large economic losses to the poultry industry annually. Gut microorganismal alterations directly affect the health of the body. To understand how E. tenella affects its host, we analysed the changes in caecal microbial diversity and the physiological and morphological changes during the peak of oocyst shedding. Infected and healthy chickens differed significantly in caecal pathology and blood indicators. At the genus level, the abundances of Faecalibacterium, Clostridium, Lachnoclostridium, Gemmiger, Flavonifractor, Pseudoflavonifractor and Oscillibacter were significantly decreased in the infected samples, whereas Escherichia, Nocardia and Chlamydia were significantly increased. Functional gene pathways related to replication, recombination and repair, and transcription were significantly decreased, and functional genes related to metabolism were highly significantly reduced in the infected samples. Furthermore, in the infected samples, E. tenella reduced the haemoglobin levels and red blood cell counts, greatly reduced the beneficial bacteria and increased the potentially pathogenic bacteria. This study provides a research basis for further understanding the pathogenic mechanisms of E. tenella and provides insight for potential new drug development.

RESEARCH HIGHLIGHTS

• First simultaneous description of caecal microbiota and physiological indicators during E. tenella infection.

• Metagenomics used to explore functional properties of chicken caecal microbiota during E. tenella infection.

• Caecal microbial compositions and functional genes altered significantly after infection.

• Blood indicators and caecal morphology were significantly altered in the infected group.

KEYWORDS:

• Eimeria tenella
• microbial community
• metagenomic sequencing
• blood indicator
• histological evaluation
• functional gene

Ethical statement

Experimentation with animals was approved by the Animal Ethics Committee of Guizhou University (approval number EAE-GZU-2021-T012) and followed the Regulations of Experimental Animals of Guizhou Authority.

Acknowledgements

We specially thank Prof. Xianyong Liu from the Parasite Research Group of the School of Veterinary Medicine of China Agricultural University, who provided us the E. tenella oocysts. We also thank Traci Raley, MS, ELS, from Liwen Bianji (Edanz) (www.liwenbianji.cn/) for editing a draft of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was supported by grants from the National Natural Science Foundation of China [grant number 32060786], [grant number 31660723]; the Science and Technology Foundation of Guizhou Province [grant number QKHZC-2018-2264]; the Guizhou University Introduced Talents Scientific Research Project [GRDJHZ-2020-69]; the Science and Technology Program of Guizhou Province [grant number QKHJC-ZK-2022-116]; the Science and Technology Program of Guizhou Province [grant number QKHJC-ZK-2022-129]; Guizhou Province General Colleges and Universities Youth Science and Technology Talent Growth Project [grant number QJH-KY-2022-151].