Effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of starter White Pekin ducks

Two experiments were conducted to evaluate the effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of White Pekin ducks from hatch to 21 d of age. The 6 supplemental vitamin E levels (0, 5, 10, 20, 40, and 100 mg DL-α-tocopheryl acetate/kg) and 4 supplemental vitamin E levels (0, 10, 20, and 100 mg DL-α-tocopheryl acetate/kg) were utilized in experiments 1 and 2, respectively. All treatments were replicated 8 times using 7 ducklings per pen in experiment 1 and 6 times using 8 birds per pen in experiment 2. All ducks were raised from hatch to 21 d of age. In both experiments, compared with ducks fed vitamin E-supplemented diets, the birds fed basal diets with no supplemental vitamin E had less weight gain and feed intake (P < 0.05) but these two criteria showed no linear or quadratic response to increasing supplemental vitamin E levels (P > 0.05). On the other hand, the plasma or liver α-tocopherol was dependent on supplemental vitamin E levels. The plasma or liver α-tocopherol increased linearly or quadratically as supplemental vitamin E increased gradually in both experiments (P < 0.05). In addition, supplementation of vitamin E in basal diets could reduce liver lipid peroxidation but the further reduction did not take place when supplemental vitamin E level was above 5 mg/kg in experiment 1 or 10 mg/kg in experiment 2 due to no linear or quadratic response to increasing supplemental levels of this vitamin (P > 0.05). Therefore, when including the vitamin E content of basal diets, the dietary total vitamin E should not be less than 10 mg/kg in order to keep optimal growth performance and antioxidant capacity of starter Pekin ducks from hatch to 21 days of age. Plasma or liver α-tocopherol were sensitive indicators for the status of this vitamin.