The effects of dietary vitamin B12 deficiency on sperm maturation in developing and growing male rats.

To evaluate the role of vitamin B12 on spermatogenesis, the effects of dietary vitamin B12 deficiency on sperm maturation in developing rat fetuses and young growing rats were examined. The vitamin B12-deficient diet was given to all the animals for three different periods: whole period (gestation to mature), gestation period (gestation to weaning), or immature period (3-12 weeks postnatal). Sperm examination revealed that the sperm count was markedly lower in male progeny (F1) that were vitamin B12-deficient during the whole period. In addition, a significantly higher number of abnormal sperm, such as tailless and amorphous sperm, was observed. In male rats that were vitamin B12-deficient during the immature period, the incidence of abnormal sperms was 14.4% and 4.8% for tailless and short tail, respectively. The motion rates, such as path velocity and straight line velocity, were decreased to 20-40% of the control value in rats that were vitamin B12-deficient both during the whole and gestation periods. However, no effects of vitamin B12 deficiency on sperm motility were observed during the immature and mature periods. From these findings, we suggest that dietary vitamin B12 deficiency during pregnancy may induce irreversible damage in the germ cells of embryos and affect the maturation of spermatozoa.