Effects of different levels of organic Selenium supplementation on fattening performance, carcass characteristics and blood GSH-Px activity in lambs

The aim of this study was to determine the effects of organic selenium supplementation on growth performance, slaughtering and carcass characteristics and blood GSH-Px activity in lambs. A total of 24 weaned, 2-2.5 months old, Anatolian Merino lambs were used in the experiment and randomly divided into 3 equal groups (n = 8): while control group was fed only with basal diet (250 g/ day alfalfa hay and concentrate ad libitum). the 2 other groups were fed with basal diet and supplemented with 200 and 300 ppm respectively organic selenium (Sel-plex) for 84 days. Although body weights did not significantly differ among the 3 groups, significant increases of the cumulated weight gains compared to the controls were recorded in lambs supplemented with 200 ppm of Sel-plex since the 28(th) day until the 86(th) day and the food conversion ratios (total, for concentrate or for roughage) were also improved in this group. The cold carcass yield and the inner fat ratio were significantly reduced in all supplemented animals whereas testicle weight was significantly increased in lambs receiving 200 ppm Sel-plex and bone yield was significantly decreased in lambs treated with the highest dose (300 ppm). Blood glutathione peroxidase mean activity was also greatly enhanced in both Sel-plex treated groups. These results show the beneficial effects of organic selenium supplementation (Sel-plex) with moderate dose (200 ppm) on growth and fat metabolism probably linked to the improvement of antioxidant systems.