Effect of organic and mineral selenium sources on production performance and selected physiological indicators in swine

The study was conducted on sows (hybrids of wbp x pbz breeds) and their offspring (until day 75 of life) kept on a farm. The aim of the experiment was to compare the effects of different sources of selenium (Se) on the production performance of the animals, Se content in their blood, the level of Se in sow's colostrum, as well as Gpx, haptoglobin and immunoglobulin levels in the serum of sows and their offspring. Experimental feed mixtures for pregnant sows (LP), lactating sows (LK) and piglets (prestarter and starter) in each treatment had an identical basic composition, differing only in the type of selenium forms. Group I received a mineral form of Se in an amount of 0.2 mg/kg; group II received a mixture of a Se amino acid chelate and the mineral form of Se (0.1 mg/kg of each); group III received a Se amino acid chelate (0.2 mg/kg), and group IV received Se-enriched yeasts (0.2 mg/kg). Beneficial effects of the organic forms of Se were evident already in the lactation period. Sows, especially those from group II receiving 0.2 mg/kg of organic Se, had a higher feed intake, which was related to a higher milk production during lactation. As a result, on the weaning day, piglets from this group were significantly heavier than the other piglets. After weaning, as well, the piglets in this group were significantly heavier. These results were confirmed by parameters of blood serum and whey colostrum. Selenium as a chelate was more available than the mineral and enriched yeast forms. For this reason, the animals receiving the chelate were healthier (fewer inflammations were noted). The animals in this group also showed a better feed conversion compared with the others. The Gpx level in sows' serum varied depending on the treatment. The highest level of this parameter was determined in sows from group III (receiving 0.2 mg/kg of organic Se), and it differed significantly from its value in the control group. The results showed that the Gpx level was related to the Se concentration in blood serum, which was also confirmed by a higher production of selenocysteine (a part of Gpx). Cells of the animals from this group were better protected against free radicals. Administration of 0.1 mg/kg of organic Se positively affects the performance of animals, but the recommended level in feed is 0.2 mg/kg of a selenium-containing amino acid.