Impact of Adding Different Levels of Nanoselenium to Duck Diets on Growth Performance, Immunity Status, Antioxidant Activity and some Blood Parameters

An experiment was designed to investigate the effects of dietary supplementation of various concentrations of nanoselenium (NS) on the growth performance, immune status, antioxidant activity and hematological parameters of ducks. A total of 40 (1 day old) Pekin ducklings were equally divided into groups of 10 ducklings each. The 1st group was considered a control and was fed basal diet ad-libitum without nanoselenium (NS) supplementation; 2nd group (fed basal diet + 0.2 mg NS/kg diet); 3rd group (fed basal diet + 0.4 mg NS/kg diet) and 4th group (fed basal diet + 0.6 mg NS/kg diet). The selenium content of the unsupplemented control diet was 0.09 mg/kg during the starter period (0-2 weeks) and 0.07 mg/kg during the grower-finisher period (2-10 weeks). All feeds were formulated according to NRC (1994) to meet the nutritional needs of growing ducks. The experiment was extended for 10 weeks. Growth performance parameters such as body weight development, weight gain, feed consumption, feed-to-gain ratio, performance index and mortality were recorded. At the end of experiment, three randomly selected ducks from each group were selected to assess immune status, antioxidant activity, and blood biochemical parameters. The results showed that ducks fed on diets supplemented with different levels of nanoselenium had significantly higher body weight and weight gain (P<0.05) and consumed less feed than ducks fed the control diet. The third group had the highest body weight and weight gain and the lowest feed intake, followed by the second and fourth groups respectively. The NS supplemented birds had no mortality throughout the experimental period compared with control group which recorded highest mortality rate (20%). Different levels of NS supplementation improved the feed conversion ratio and performance index, the best values was achieved in 3rd group followed by 2nd and 4th groups, respectively. Addition of NS to duck diets significantly (P˂0.05) increased the serum immunoglobulins (IgA, IgG, IgM), glutathione peroxidase (GPx) and superoxide dismutase (SOD) levels, but decreased the malondialdehyde (MDA) levels compared to control. Concerning blood picture, NS supplementation significantly increased white blood cell and lymphocytic counts (P<0.05). However, no significant differences in other hematological parameters between tested groups. In conclusion, the present study found that supplementing duck diets with nano-selenium improved growth performance parameters, immune status, antioxidant activity, blood picture and 0.2-0.4 mg/kg is considered the optimum nano-Se supplementation level, and the maximum nano-Se supplementation level for ducks should not exceed 0.6 mg/kg