Anal Sucking-like Movements in the Chicken and Chick Embryo Followed by the Transportation of Environmental Material to the Bursa of Fabricius, Caeca and Caecal Tonsils

Abstract

Anal sucking-like movements and the uptake of tracer materials by the bursa Fabricii, caeca and caecal tonsils were studied in chick embryos and chickens of various ages. In embryos, aged 15 days or more, sucking movements were associated with transportation of colloidal carbon from the anal lips into the bursal lumen. Since sucking was found only after mechanical irritation of the skin, occurring simultaneously with slow respiratory efforts, we conclude that it may not have any biological importance during the embryonal period. After hatching, the sucking movements were spontaneous and occurred also in old chickens after bursal involution. In young chickens movements were simultaneous with the respiratory motions, increasing in older birds. In chickens with intact bursa, anal sucking was associated with effective transport of tracer materials into the bursal lumen, immediately after application; later the tracers were found in the caecal lumina. Also in old chickens, after bursal involution, the tracers were taken up into the cloaca, colon and the caeca. As in the bursa, a further transport of colloidal carbon from the lumen into the mucosal lymphoid tissue was found also in the caecal tonsils, but in the bursa this transport was by far more effective.