In ruminant animals like cows and sheep, bacteria in the stomach produce vitamin B12 by breaking down inorganic minerals found in the plants they eat.
Mechanism
Synthesis from 2 studies
Rumen bacteria build vitamin B12 using cobalt and a special chemical from the plants the animal eats. This vitamin helps the bacteria turn food into energy without making too much acid, while also making more protein and useful nutrients. Without these two ingredients, the bacteria can't make...
Most probable mechanism
Bacteria in the rumen use cobalt from plant material and a special chemical called dimethylbenzimidazole to build vitamin B12. This vitamin helps the bacteria turn food into energy more efficiently, which reduces acid buildup and lets them make more protein and useful fatty acids. Without these two building blocks, the bacteria can't make enough vitamin B12, and the whole process slows down.
Cobalt ions from dietary plant material are absorbed by rumen microorganisms and incorporated into the core structure of vitamin B12 as the central metal atom.
5,6-Dimethylbenzimidazole, derived from microbial metabolism or dietary sources, binds to the cobalt ion to form the lower ligand of the vitamin B12 molecule.
The assembled vitamin B12 acts as a coenzyme for methylmalonyl-CoA mutase, enabling the conversion of methylmalonyl-CoA to succinyl-CoA in the propionate metabolism pathway.
Efficient propionate metabolism reduces accumulation of lactic acid intermediates, lowering rumen acidity and stabilizing pH.
Vitamin B12 enhances the activity of ammonia-assimilating enzymes in rumen microbes, promoting the incorporation of ammonia nitrogen into microbial protein.
Increased propionate flux supports higher total volatile fatty acid production, improving energy availability for the host.
Evidence from Studies
Supporting (1)
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Contradicting (1)
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