Evaluating the impact of maternal vitamin D supplementation: I. Sow performance, serum vitamin metabolites, and neonatal muscle characteristics
J. R. Flohr, J. C. Woodworth, J. R.Bergstrom, M. D. Tokach, S. S. Dritz, R. D. Goodband and J. M. DeRouchey
In Exp. 1, 56 gestating sows (PIC 1050; 35d post insemination) were used in a 30-d trial to determine serum 25(OH)D3 response to increasing concentrations of dietary vitamin D3. Sows were randomly allotted to 1 of 7 dietary D3 treatments (200, 800, 1,600, 3,200, 6,400,12,800, or 25,600 IU of added D3 per kilogram of complete diet) with 8 sows per treatment. Increasing D3 increased (quadratic; P < 0.001) serum 25(OH)D3 with the response depicted by the prediction equation: serum 25(OH)D3, ng/mL =35.1746 + (0.002353 × dietary D3, IU/d) − (0.0000000156 × dietary D3, IU/d2). In Exp. 2, 112 sows and their litters were used to determine the effects ofdietary vitamin D regimen on sow performance, subsequent preweaning pig performance, neonatal bone and muscle characteristics, and serum vitamin metabolites. Sows were allotted to 1 of 4 dietary treatments 3 to 5 d following breeding: 800, 2,000, or 9,600 IU of D3 per kilogram of the diet or 50 μg of 25(OH)D3 (2,000 IU of D3 equivalent from Hy-D, DSM Nutritional Products, Parsippany, NJ) per kilogram of diet. There were 25 to 27 sows per treatment. Increasing dietary D3 increased (linear, P = 0.001) serum 25(OH)D3 of sows on d100 of gestation, at farrowing, and at weaning. Increasing D3 in sow diets increased piglet serum 25(OH)D3 at birth (linear, P = 0.001) and weaning (quadratic, P = 0.033). Sows fed 50 μg of 25(OH)D3/kg had intermediate (P <0.004) serum 25(OH)D3 concentrations on d 100 of gestation, at farrowing, and at weaning compared with sows fed 2,000 IU of D3/kg and sows fed 9,600 IU of D3/kg. Pigs from sows fed 50 μg of 25(OH)D3/kg had greater serum 25(OH)D3 compared with pigs from sows fed 2,000 IU of D3/kg, but at weaning, serum 25(OH)D3 concentrations were similar. Also, pigs from sows fed 9,600 IU of D3/kg had greater (P = 0.011) serum 25(OH)D3 at birth and weaning compared with pigs from sows fed 50 μg of 25(OH)D3/kg. Maternal performance, litter characteristics, neonatal bone ash content, and neonatal muscle fiber characteristics were largely unaffected by the dietary vitamin D treatments. Overall, D3 and 25(OH)D3 are both useful at increasing serum 25(OH)D3 concentrations, but more D3 (on an equivalent IU basis) is needed to achieve similar serum 25(OH)D3 responses compared with feeding 25(OH)D3. Concentration of maternal vitamin D supplementation in lactation impacted milk transfer of the vitamin more so than the form of the vitamin, as evidence by the weaned pig serum 25(OH)D3 concentrations.