Trace mineral metabolism in non-gravid, gestating and lactating gilts fed two dietary levels of manganese.

Six pairs of littermate Landrace gilts weighing 100-110 kg were randomly assigned to one of the experimental diets; 1) Low Mn: basal corn-soya diet (10 mg/kg) or 2) High Mn: basal+supplement (84 mg/kg), and maintained in individual stainless steel metabolic cages. Consumption of the semipurified diet was restricted to 2.5 kg/d with water available at all times ad libitum. Retention of Mn, Cu, Zn, and Fe were determined using the balance technique in the non-gravid state and at 30, 60 and 100 days of gestation. Blood samples were collected at the initiation of each balance period, the day before farrowing and at the end of lactation. Colostrum and milk were collected at birth and one week after farrowing, respectively. Piglets were bled at birth and weaning. Significant differences in mineral retention were not detected between the two dietary treatments. Retention of Mn was not influenced by pregnancy and averaged 1.37 +/- 0.92 mg/d and 0.97 +/- 0.92 mg/d for the supplemented and basal treatments, respectively. Fecal Zn excretion declined (P less than 0.01) at 100 days of gestation in both treatment groups and thus tended to improve Zn retention. Plasma Mn did not reflect Mn intake, but was significantly reduced at 100 days of gestation from the non-gravid state. Colostrum and milk from supplemented dams tended to contain higher concentrations of Mn. Total litter weight at birth was significantly greater for supplemented gilts.