Matte, J. J., Guay F. and Girard, C. L. 2006. Folic acid and vitamin B12 in reproducing sows: New concepts. Can. J. Anim. Sci.
86: 197–205. In pig nutrition, the present gaps in the information on B-complex vitamins have important implications for empiri-
cism and disparities in dietary recommendations. This is particularly true for folic acid (B9) and vitamin B12. Recent studies sug-
gest that the beneficial effects of B9 on sow prolificacy may be due to enhanced embryo development and survival. Embryo
synthesis of estrogens and uterine secretions of prostanoids and cytokines during attachment appear to be key factors in vitamin
B9 regulation of embryo development. Nevertheless, embryo and uterine responses to B9 are often more pronounced in multi-
parous sows than in gilts. This parity effect on B9 responses can be attributed to the metabolic interaction with another vitamin,
specifically B12. The two vitamins are essential for modulating the transfer of one-carbon groups for protein and DNA synthesis,
methylation and gene expression. The metabolic pathway involved is the remethylation of methionine from an intermediary
metabolite, homocysteine. A deficiency in B9 or B12 may induce a local or systemic accumulation of homocysteine, a powerful
pro-oxidant known to impair embryo development. It appears that B12 status, which is about two times lower in gilts than in mul-
tiparous sows, could be a limiting factor for the action of vitamin B9 on uterus and embryo metabolism during the first pregnan-
cy. Vitamin B12 status is particularly critical since, in early gestation, the sow uterus drains off a massive amount of B12,
representing two to three times the B12 plasma pool. Dietary B12, at levels 10 times higher than recommended, have been found
to maximize B12 status and minimize homocysteine accumulation in first parity sows. It appears that an optimum B9:B12
ratio,
which has yet to be estimated, would enable vitamin B9
to have full beneficial effects on sow prolificacy. In the future, it is like-
ly that there will be an even greater need for updated information on the requirements for B-complex vitamins given the “dietary
fine tuning” that is necessary for the highly producing pigs that have been selected in recent decades.
Matte, J. J., Guay F. and Girard, C. L. 2006. Folic acid and vitamin B12 in reproducing sows: New concepts. Can. J. Anim. Sci.86: 197–205. In pig nutrition, the present gaps in the information on B-complex vitamins have important implications for empiri-cism and disparities in dietary recommendations. This is particularly true for folic acid (B9) and vitamin B12. Recent studies sug-gest that the beneficial effects of B9 on sow prolificacy may be due to enhanced embryo development and survival. Embryosynthesis of estrogens and uterine secretions of prostanoids and cytokines during attachment appear to be key factors in vitaminB9 regulation of embryo development. Nevertheless, embryo and uterine responses to B9 are often more pronounced in multi-parous sows than in gilts. This parity effect on B9 responses can be attributed to the metabolic interaction with another vitamin,specifically B12. The two vitamins are essential for modulating the transfer of one-carbon groups for protein and DNA synthesis,methylation and gene expression. The metabolic pathway involved is the remethylation of methionine from an intermediarymetabolite, homocysteine. A deficiency in B9 or B12 may induce a local or systemic accumulation of homocysteine, a powerfulpro-oxidant known to impair embryo development. It appears that B12 status, which is about two times lower in gilts than in mul-tiparous sows, could be a limiting factor for the action of vitamin B9 on uterus and embryo metabolism during the first pregnan-cy. Vitamin B12 status is particularly critical since, in early gestation, the sow uterus drains off a massive amount of B12,representing two to three times the B12 plasma pool. Dietary B12, at levels 10 times higher than recommended, have been foundto maximize B12 status and minimize homocysteine accumulation in first parity sows. It appears that an optimum B9:B12 ratio,which has yet to be estimated, would enable vitamin B9 to have full beneficial effects on sow prolificacy. In the future, it is like-ly that there will be an even greater need for updated information on the requirements for B-complex vitamins given the “dietaryfine tuning” that is necessary for the highly producing pigs that have been selected in recent decades.
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