Effect of inorganic or organic selenium at two dietary levels on reproductive performance and tissue selenium concentrations in first-parity gilts and their progeny

A 2 x 2 factorial arrangement of treatments in a randomized complete block design was conducted at two time periods using a total of 43 first-parity gilts. Two sources of Se (selenite or Se-enriched yeast) were added at .1 or .3 ppm to corn-soybean meal diets to evaluate reproductive performance and gilt and progeny tissue Se contents. Treatment diets were initially provided approximately 60 d before breeding. Gilts were bled at periodic intervals and serum glutathione peroxidase (GSH-Px) activity and Se concentrations were determined. Milk was collected at parturition and at weekly intervals to weaning (21 d) for Se analysis. Liver and loin tissues were collected from stillborn (n = 17) and neonatal pigs (n = 19) before colostrum consumption. Three pigs from each litter were bled at weaning, and six pigs per treatment group were killed (two/litter) and tissue (liver, loin, kidney) collected. Three to four sows per treatment were killed at weaning and tissue (loin, liver, pancreas, kidney) collected. Tissues collected from each were analyzed for Se. Dietary Se level or Se source had no effect (P > .15) on gilt reproductive performance. Gilt serum GSH-Px activity was generally similar at the .1 and .3 ppm Se level for either Se source, whereas serum Se was consistently higher when the dietary Se level was .3 ppm. Colostrum Se content was unaffected by Se source and Se level, but milk Se increased as the dietary Se level increased and when the Se-enriched yeast source was fed, resulting in an interaction response (P < .01). Loin tissue had similar Se contents between stillborn and neonatal pigs. Loin Se content was higher when dietary Se level increased (P < .05) and when the Se-enriched yeast source (P < .01) was fed to gestating gilts. Weanling pig loin Se content increased as dietary Se level increased (P < .01) and when the Se-enriched yeast source was fed (P < .01). A higher liver Se content in weaned pigs also resulted when the dietary Se level was .3 ppm (P < .08) and when the Se-yeast(P < .01) was provided. Weanling pig serum GSH-Px activity was similar regardless of the Se level or Se source fed to the dam, but serum Se increased when the .3 ppm Se level and the Se-yeast was fed to the gilt. If GSH-Px activity is used as the criterion to evaluate Se adequacy, then .1 ppm Se from either Se source was adequate, but if higher milk Se or pig tissue content is desired, then a .3 ppm Se level from the Se-enriched yeast source was superior to inorganic Se.