The effects of nitrilotriacetic acid on solubilities of zinc, copper, manganese, and iron in the stomach of sheep

Abstract

Four sheep, each prepared with a rumen fistula and reentrant cannula in the proximal duodenum, were used to study the effects of ruminal administration of nitrilotriacetic acid on solubilities of zinc, copper, manganese, and iron in rumen and duodenal digesta. The sheep received a pelleted diet and were dosed with 0, 300, 600, and 1200 μg of nitrilotriacetic acid per gram of diet via the rumen fistula.Higher concentrations of soluble zinc, manganese, and iron, but not copper, were found in the rumen of the sheep when they were dosed with nitrilotriacetic acid. The concentrations increased with increasing dose of the acid. However, only the solubility of iron was increased in the duodenal digesta. Concentrations of soluble zinc and manganese in the rumen increased, whereas copper decreased, during the first 2 h after feeding. The pattern was reversed thereafter. Changes in the concentrations of soluble iron during 6 h after feeding were comparatively small.It is concluded that the solubility of iron in the stomach of sheep is increased by ruminal administration of nitrilotriacetic acid.