Graded levels of pyridoxine in the rat diet during gestation and the physical and neuromotor development of offspring

Abstract

Female rats were maintained throughout gestation on purified diets containing 400, 100, 75, 25, or 0% of the NRC recommendation for pyridoxine and transferred to the 400% vitamin B₆-supplemented diet during lactation. Physical development of the offspring was assessed by measuring crownrump size, body weight, and the times at which the external ear flap opened, the eyes opened, incisors erupted, and hair growth obscured the genitalia. Neuromotor development and coordination were assessed by noting total activity, crawling, head lifting, head waving, standing supported or unsupported, righting reflex, and startle reaction to sound. Grooming was employed as a measure of spontaneous activity. Restriction of pyridoxine resulted in lower body weights, slow physical development, and impaired neuromotor development in the rat pups. The severity of these effects depended on the particular parameter under consideration and the level of vitamin B₆ supplementation, being most marked in the groups receiving the lowest levels of pyridoxine. There was a tendency for the pups from the 100% vitamin B₆-supplemented dams to exhibit inferior performance to that of the 400%-supplementation group in some areas. Pups from the most severely restricted groups (0 and 25% pyridoxine) failed to thrive and did not survive the lactation period. The importance of maternal pyridoxine supplementation during pregnancy has been demonstrated.