Large Overlap Between the Intestinal and Reproductive Tract Microbiomes of Chickens

Naama Shterzer, Nir Rothschild, Yara Sbehat, Einav Stern, Albert Nazarov, Erez Mills*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Recent work characterized the chicken reproductive tract (oviduct) microbiome composition and its similarity to the egg and chick microbiomes. However, the origin of the oviduct microbiome has not been addressed yet. Here, we characterized the microbiome composition along the oviduct (infundibulum, magnum, and shell gland) as well as in the gut (jejunum and cecum) of broiler breeders at 37 weeks of age of the Cobb industrial breed. We found that while the microbiome composition along the oviduct is similar, the three sites, jejunum, cecum, and oviduct hold distinct microbiomes. However, there was also a large overlap in the composition of the gut and oviduct microbiomes, with 55 and 53% of amplicon sequence variants (ASVs) representing 96 and 90% of the total abundance in the jejunum and cecum, respectively, shared with the magnum. Furthermore, we identified a strong correlation between the relative abundance of ASVs in the gut and their probability to be found in the oviduct. These results suggest that material from the gut travels the full length of the oviduct. This is possibly the result of chicken physiology which includes the cloaca, a cavity to which both the intestinal and reproductive tracts open into. As the cloaca is common to birds, reptiles, amphibians, most fish, and monotremes, our finding may be relevant to many vertebrates. Importantly, these results indicate that mere presence in, and ascending of the oviduct are not virulence characteristics specific to pathogens, as commonly thought, but are the result of chicken physiology and characterize all gut bacteria. Furthermore, whereas a vertical transmission route from the hen to the chick has been suggested, our work starts laying a mechanistic foundation to this route, by describing the movement of gut bacteria to the oviduct, where they may be enclosed in the developing egg. Last, as our results show that gut material travels the full length of the oviduct, fertilization in poultry occurs in the presence of at least bacterial products if not live bacteria, and therefore food additives, probiotics, and diet possibly have a much more direct effect on reproduction and egg formation than previously considered.

Original languageAmerican English
Article number1508
JournalFrontiers in Microbiology
StatePublished - 14 Jul 2020

Bibliographical note

Publisher Copyright:
© Copyright © 2020 Shterzer, Rothschild, Sbehat, Stern, Nazarov and Mills.


  • 16S rDNA (amplicon sequencing)
  • gut micobiota
  • oviduct microbiota
  • poultry
  • vertical transmission of bacteria


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