Microbiota continuum along the chicken oviduct and its association with host genetics and egg formation

Managing Gut Microbiota through In Ovo Nutrition Influences Early-Life Programming in Broiler Chickens

“…However, new technologies in the field, such as next-generation sequencing techniques, have shed light on the fact that this conventional idea is no longer accurate [ 41 ]. These techniques allowed scientists to demonstrate that pathogenic bacteria can transfer vertically or horizontally to eggs and subsequently to the chick’s gut [ 42 , 43 ].…”

“…The microbiota diversity was found to be increased throughout the reproductive tract, beginning at the infundibulum and extending to the cloaca, but the communities present in the vagina, uterus, and other reproductive tract regions were clearly distinct. Though some parts of the reproductive tract are resistant to various pathogens due to the secretion of lysozyme and other antimicrobial proteins in these parts [ 44 , 45 ], some pathogenic bacteria are present in their microbiome [ 42 ]. Hence, pathogens can contaminate eggs during egg formation and oviposition.…”

“…Interestingly, egg white and the embryo’s gut exhibited similar microbial structures. In a more recent study, Escherichia-Shigella and Enterococcus were two dominant genera in the maternal oviduct and might also be found in yielded eggs [ 42 ]. These findings dispute the idea that avian eggs and their embryos are entirely sterile before hatching, as evidenced by the fact that embryos swallow yolk by the latter stages of embryonic development.…”

Recovered microbiome of an oviparous lizard differs across gut and reproductive tissues, cloacal swabs, and feces

“…While localization has been seen in other reptiles (Colston et al, 2015;Costello et al, 2010;Keenan et al, 2013;Kohl et al, 2017), the cloaca in previously sampled reptiles was found to have relatively high diversity and to host representatives from the upper regions of the gut. This pattern may be expected as the cloaca is the terminus of the GI and reproductive systems, and is often assumed to be both inoculated by feces that pass through and influenced by sexual transmission during copulation (Videvall et al, 2018;Wen et al, 2021;White et al, 2011). Similarly, the reproductive tract of chickens shows increasing levels of diversity from oviducts to cloaca, which has the highest diversity (Wen et al, 2021).…”

“…This pattern may be expected as the cloaca is the terminus of the GI and reproductive systems, and is often assumed to be both inoculated by feces that pass through and influenced by sexual transmission during copulation (Videvall et al, 2018;Wen et al, 2021;White et al, 2011). Similarly, the reproductive tract of chickens shows increasing levels of diversity from oviducts to cloaca, which has the highest diversity (Wen et al, 2021). In contrast to these previously described patterns, the cloacal microbiome of S. virgatus females is low diversity, especially at the Family and Phylum level at which it was dominated byEnterobacteriaceae and Protobacteria, and is distinct from upper intestine, oviductal, and fecal microbiomes.…”