Metabolic activity of manganese during late gestation of first-litter gilts

Four pairs of littermate Landrace gilts consuming either a low manganese (LMn) basal corn-soya diet (10 mg/kg) or a high Mn (HMn) supplement diet (84 mg/kg) were maintained in individual stainless steel metabolic cages throughout gestation. On the 100th day of gestation 200 microCi of 54Mn was administered intravenously. Total collection of feces and urine was conducted for a seven-day period. The sows were sacrificed after a three-week lactation period and several tissues excised. All samples were assayed for stable Mn content and 54Mn activity. Urinary excretion of 54Mn was negligible and not dependent on dietary Mn intake. Dietary Mn intake did not influence the rate of 54Mn elimination via the feces. The biological half-life (BHL) of the body Mn pool in late gestation averaged 54 days and was not influenced by treatment. The fecal Mn of endogenous origin was similar between treatments averaging 0.24 mg/d and yielded true absorption estimates of 1.31 and 1.61 mg/d for the LMn and HMn diets or 4.41% and 0.77% of dietary intake.