Long-term dietary supplementation of organic selenium modulates gene expression profiles in leukocytes of adult pigs

Seventy-two pigs at 34.4kg body weight (BW) were allotted to two treatments with six replicates/treatment and six pigs/pen: the CON (negative control, no added selenium (Se)) and the OS (0.36mg/kg added selenium from selenium-enriched yeast). Pigs were fed until 130kg BW. The CON diet contained 0.18mg/kg indigenous Se whereas the OS diet contained 0.54mg/kg Se. Blood samples were collected at 130kg BW and further processed for microarray analysis, prepared with 885 genes related to immune function of pigs. Among those, 28 genes related to improved immune status and innate immunity were up-regulated (P<0.05) in leukocytes from Se-fed pigs and those include major histocompatibility class I (>1.66), arginase I (>1.27), integrin beta-1-subunit (>1.20), toll like receptor 2 (>1.12) and double-stranded RNA-dependent protein kinase. However, 24 genes including tissue factor (<4.70), serum amyloid A-2 protein (<3.11) and p27Kip1 (<1.42) were down-regulated (P<0.05) in leukocytes from Se-fed pigs. Expression of four selected genes was validated using quantitative PCR (qPCR) showing significant correlation between mircroarray analysis and qPCR analysis. This study indicates that a long- term dietary supplementation (0.3%) of organic Se improves the expression of genes that are related to enhanced immunity of pigs.