Absorption of Vitamin B12 from the Cecum of the Hen.

Summary 1. Cecectomy did not shorten the time required to deplete the egg of vit. B12 when the hen was fed a corn-soybean meal type diet deficient in the vitamin. Thus it appears that the hen on a deficient diet does not derive any appreciable benefit from the B12 present in the ceca. 2. Following injection of Co-60 labeled vit. Bi2 into the occluded cecum of the hen7 small amounts of radioactivity, chromatographically similar to B12 were found in the tissues. The data indicate that this B12 was absorbed as the free vitamin and that the Bi2 retained in the cecum became bound. It is suggested that the vit. B12 normally present in the ceca of the hen is essentially unavailable for absorption. 3. When S-35 labeled methionine or sodium sulfate was injected into the cecum an average of 93 and 96%, respectively, of the dose was absorbed within 48 hours. Studies on the uptake of these 2 compounds in the blood show that they were rapidly absorbed.