Prolonged feeding of high dietary levels of organic and inorganic selenium to gilts from 25 kg body weight through one parity.

Abstract

An experiment evaluated the selenosis effects from feeding high dietary Se levels of organic or inorganic Se sources to growing gilts with the dietary treatments continued through a reproductive cycle. A total of 88 gilts were allotted at 25 kg BW to two replicates in a 2 x 4 factorial arrangement in a randomized complete block design. Inorganic Se (sodium selenite) or organic (Se-enriched yeast) Se were added to diets at 0.3, 3, 7, or 10 ppm Se. At 105 kg BW, four gilts per treatment were killed and livers collected for Se analysis. At 8 mo of age, three gilts from each treatment group were bred and fed their treatment diet, with subsequent reproductive performance and selenosis effects evaluated. Serum collected at various intervals in gilts, sows, and progeny measured glutathione peroxidase activity and Se concentrations. Sow colostrum and milk was analyzed for their Se concentrations. Three pigs per treatment were killed before colostrum consumption and at weaning (14 d) and tissue collected for Se analysis. Gilt gains (P < 0.01) and feed intakes (P < 0.05) declined during the grower period as dietary Se level increased for both Se sources. Serum and liver Se concentrations increased as dietary Se level increased and was higher when organic Se was fed (P < 0.01). Sows fed dietary Se levels at > 7 ppm had lower gestation weights (P < 0.05) and lower lactation feed intakes (P < 0.05). As Se level increased, sows fed organic Se had a lower number of live pigs born (P < 0.05) and weaned fewer pigs (P < 0.05) with lower litter gains (P < 0.05) than did sows fed inorganic Se. Colostrum and milk Se concentrations increased as dietary Se levels increased particularly when organic Se was fed (P < 0.01). Neonatal and weanling pig tissue Se and serum Se concentrations increased as dietary Se level increased and when organic Se was fed, resulting in interaction responses (P < 0.01). Pigs nursing sows fed > 7 ppm inorganic Se had hoof separation and alopecia, with the severity being greater when sows were fed the inorganic Se source. These results suggest that both the organic and inorganic Se sources were toxic when fed at 7 to 10 ppm for a prolonged period, but organic Se seemed to express the selenotic effects more on reproductive performance, whereas inorganic Se was more detrimental during lactation.