Relationship of Vitamin A to S35 Metabolism in the Baby Pig

Abstract

Two experiments were employed in studying the relationship between vitamin A and S³⁵ metabolism in pigs. The first showed that maximum accumulation of S³⁵ in blood and lung tissues occurred 9 hours or less following intraperitoneal injection of Na₂S³⁵O₄; about 17 hours were required for maxima in ear cartilage and the costochondral junctions. In the second experiment, pigs maintained at various levels of dietary vitamin A were sacrificed 17 hours after intraperitoneal injection of Na₂S³⁵O₄. An extreme deficiency in vitamin A effected a high concentration of S³⁵ in all tissues, especially in the rib junction. The addition of dietary vitamin A considerably reduced this activity; minimum activity occurred at the level of 790 I.U./lb. of feed. Higher levels of the vitamin A (up to 11,393 I.U./lb. of feed) brought about some return to higher specific activities in the tissues investigated. The relationships between S³⁵ accumulation, growth and cerebrospinal fluid pressure suggest that the sulfur metabolism of the growing regions of bones is intimately concerned with bone growth and the pathological spinal pressures in vitamin A deficiency. The appearance of metaplasia in the interlobular ducts of the parotid gland would seem to be less frequent in the pig than that reported for the bovine animal. Color of the thyroid glands was influenced by level of vitamin A intake. Pigs receiving the levels of vitamin A near the optimum for maximum weight gain possessed the darkest colored glands.