The Synthesis of Vitamin B12 After Oral and Parenteral Administration of Inorganic Cobalt to Cobalt-Deficient Sheep

Abstract

The level of vitamin B12 in the blood of sheep on a cobalt-deficient ration decreased rapidly. However, the lambs continued to eat well and gained weight for some time after the level of B12 in the blood declined to low levels. This suggests that tissue vitamin B12 is efficiently conserved. The administration of cobalt orally to cobalt-deficient lambs significantly increased the vitamin B12 level in the blood, kidney, pancreas, adrenals, rumen-reticulum, omasum-abomasum, duodenum-jejunum and ileum; the total vitamin B12 content was significantly increased in the liver, kidney, pancreas, rumen-reticulum, omasum-abomasum, duodenum-jejunum, ileum, cecum and large intestine. The parenteral administration of cobalt to the deficient lambs failed to significantly increase the vitamin B12 level in the blood or body tissues. However, the vitamin B12 content in the cecum and large intestine was significantly increased, presumably as a result of bacterial synthesis following the excretion of cobalt into the duodenum via the bile.