Role of vitamin B 12 in methionine and valine metabolism in chickens
Snegireva, L.V.; Bekker, V.F.; Areshkina, L.Ia.
Prikladnaia Biokhimiia i Mikrobiologiia 8(4): 475-480
1972
ISSN/ISBN: 0555-1099 PMID: 4670423 Document Number: 47334
Chicks from 2 days old were kept on wire floors and given a diet with 18% protein low in vitamin B-12 and methionine and somewhat low in lysine. The control group on that diet alone had methionine 3% of crude protein, against the recommended 4%. Two test groups had methionine added to make up the norm and 2 other groups an excess of 3 times the norm; of each pair of groups one got also vitamin B-12 50 mu g/kg. Two additional groups with normal methionine were given sodium propionate 1.5% by weight of the diet with or without added vitamin B-12. After 32 days subgroups of 4 or 5 birds were given for 4 days 3 times the normal amount of valine or 1% propionic acid.Weight gain in 30 days was greatest with normal methionine intake and added vitamin B-12 and least with excess methionine. Vitamin B-12 in the liver (estimated with Escherichia coli 113-3) was low unless the vitamin was added to the diet. Excretion of methylmalonic acid was not affected by adding methionine but rose tenfold on the diet with added propionate unless the vitamin also was given. Valine given for 4 days caused an even larger increase in MMA excretion except when the vitamin was given. It is concluded that in vitamin B-12 deficiency metabolism of methionine was disturbed at a stage before the production of propionate, in addition to the block in metabolism of MMA.