نبذة مختصرة : Concomitantly with the development of the embryo and extra-embryonic structures, initial chicken egg defenses are progressively altered, which suggests that alternative mechanisms appear to protect the embryo until hatching. To better understand the role of extra-embryonic fluids in the chicken egg defense during incubation, we analyzed the biochemical composition and antibacterial properties of the chicken amniotic and allantoic fluids. As for humans, the chicken amniotic fluid protects the embryo against mechanical shocks and microbial infections. Moreover, at the 12th day of incubation, the transfer of antibacterial molecules from the egg white increases the antibacterial potential of the chicken amniotic fluid, thus protecting the embryo until hatching, and probably after, all along its digestive tract, after oral absorption of the amniotic fluid. Some of these antibacterial proteins are specific to oviparous species and/or birds, which highlights the processes of evolution and adaptation of birds to their terrestrial environment. On the other hand, the antibacterial potential of the allantoic fluid still needs to be explored, but our study demonstrated the presence of active proteases, which could contribute to the digestion and recycling of embryonic metabolic wastes. ; Avec le développement concomitant de l’embryon et des structures extra-embryonnaires, les défenses initiales de l’oeuf de poule s’altèrent, ce qui suggère la mise en place de systèmes relais pour protéger l’embryon jusqu’à son éclosion. Pour comprendre le rôle des fluides extra-embryonnaires dans cette fonction, nous avons analysé la composition et les propriétés biochimiques et antibactériennes des fluides amniotique et allantoïque de l’oeuf. Comme chez l’humain, le fluide amniotique chez la poule protège l’embryon contre les agressions physiques et microbiennes. De plus, nous avons démontré que le transfert des molécules antibactériennes du blanc au 12ème jour d’incubation augmente son potentiel antibactérien, assurant ainsi une ...
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