Abstract
This study examined the relationship between Vitamin B_<12> (B_<12>) synthesized from Cobalt (Co) in the diet and actual excreted B_<12> in coprophagy-prevented or allowed rats fed either a commercial diet (B_<12>: 170μg/kg, Co: 1380μg/kg) or a purified diet (B_<12>: 25μg/kg, Co: 1.09μg/kg contain in B_<12>). Twelve healthy Sprague-Dawley strain male rats age 4 weeks were used in this experiment. Coprophagy was prevented for the first 4 weeks, then allowed for the following 7 days. We found that B_<12> excretion was greater than B_<12> intake in each diet group, and coprophagy-allowed rats excreted larger amounts of B_<12> than coprophagy-prevented ones. This suggests that for large Co intake in rats, synthesizable-B_<12> from Co-intake is excreted. However, for small Co-intake, the entire Co-intake was used by intestinal microorganisms in synthesizing B_<12>, but excreted even if it was insufficient.
