Effects Of Vitamin E And Selenium On Growth, Immune And Antioxidant Functions Of Egg-type Ducklings

The aim of this experiment was to evaluate the effects of dietary vitamin E (VE) and selenium (Se) on growth performance, immune and antioxidant functions of egg-type ducklings in cages. The experiment was conducted with2×3compeletely randomized design by adding VE and Se to the basal diet. VE was added with two levels:suitable VE (15mg/Kg) and high VE (30mg/Kg). And Se was added with three levels:low Se (0mg/Kg), suitable Se (0.15mg/Kg) and high Se (0.30mg/Kg). The six experimental group were shown as follows:group1:15mg/Kg VE+0mg/Kg Se; group II:15mg/Kg VE+0.15mg/Kg Se; group III:15mg/Kg VE+0.30mg/Kg Se; group IV:30mg/Kg+0mg/Kg Se; group V:30mg/Kg+0.15mg/Kg Se; group VI:30mg/Kg+0.30mg/Kg Se. two hundred and sixteen one-day-old Jinding egg-type ducklings with stable body condition were randomly allotted to six dietary groups with6replicates in each group and6ducklings in each replicate. The experiment lasted for four weeks.Our results showed that, high level VE had no significant effects on daily feed intake (DFI), but average daily gain (ADG) and feed:gain (F/G) were increased. Compared with the other groups, the survival rate of ducklings in Group V(30mg/Kg+0.15mg/Kg Se) were increased, and significant dofferences were obtained between Group V(30mg/Kg+0.15mg/Kg Se) and Group I (15mg/Kg VE+0mg/Kg Se)(P<0.05).Immune organ indexes were increased to some extent, although no significant differences were observed with supplementation of30mg/Kg VE. However, additions of Se had significant effects on thymus index, spleen index and bursal index (P<0.05). A combination of supplementations with VE and Se had significant effects on bursal index (P<0.05).IgM、IgG and IL-2were increased by adding high level of VE, and IgA was also significantly increased difference (P<0.05). However, high level Se decreased the concentrations of immunoglobulins and GH. IgA were siginificantly increased with the combination of supplementations with VE and Se (P<0.05).Supplementations of high level VE could increase serum TP, ALB and strengthen the body protein metabolism. The suitable level Se could significantly increased serum TP and ALB (P<0.05), but high level Se decreased serum TP, ALB and ALB/GLB (A/G). Little differences were observed with the combination of supplementations with VE and Se in serum protein concentritions (P>0.05). With the increase of adding amount of Se, serum GLU, TG and CHO concentrations tended decline to rise. Additionally, Se had significant effects on GLU and TG (P<0.05). Associated addition of VE and Se had significant effects on CHO (P<0.05). Meanwhile, better than the other groups, serum CHO concentration of group V (30mg/Kg+0.15mg/Kg Se) was the lowest one.Supplementation of high level VE could increase the activities of T-SOD and T-AOC, and decrease the concentration of MDA. What’s more, significant effect on T-SOD was also obtained by adding high level VE (P<0.05). Suitable level Se could siginificantly increase the activities of T-SOD, GSH-PX and T-AOC (P<0.05), but high level Se decreased the activities of T-SOD, GSH-PX and T-AOC. Significant effects of associated addition of VE and Se were obtained on serum T-AOC and liver MDA (P<0.05).In conclusion, these results may represent synergism between VE and Se in this study. We indicated that addition of high level VE on the basis of suitable level Se could improve the growth, antioxidant and immune functions of ducklings, and decrease GLU and lipid of serum. Therefore, appropriate increase VE has great significances in improving the health of egg-type ducklings on the basis of meeting Se requirements.