Selenoprotein W (SelW) is expressed in the immune systems of mammals.
However, its pattern of expression in the immune organs of birds is still unclear. To
investigate the distribution of SelW and effects of dietary Se levels on the SelW mRNA
expression in the immune organs of birds, 1-day-old male chickens were fed either a
commercial diet or an Se-supplemented diet containing 0.601, 1.058, 1.514, or 2.427 mg Se
per kilogram, and 1.0, 2.0, 3.0 or 5.0 mg sodium selenite per kilogram for 90 days. The
immune organs (spleen, thymus, and bursa of Fabricius) were collected and examined for
Se content and SelW mRNA levels. The mRNA expression of SelW was detected in all the
tissues. Although Se content was the highest in the spleen, the remarkable stability of the
SelW mRNA level was observed in this organ during different times of dietary Se
supplementation. Se-supplemented diet can make the SelW expression levels higher within
a certain range in thymus and bursa of Fabricius. The present study demonstrates that SelW
is widely expressed in immune organs of birds and that Se-supplementation of the feed
increases SelW expression in the thymus and the bursa of Fabricius.