Abstract
This study was conducted to investigate the effects of broiler breeder dietary vitamin E and egg storage time on the egg characteristics, hatchability, and antioxidant status of the egg yolks and newly hatched chicks. A total of 512 71-week-old Ross 308 breeder hens were fed the same basic diets containing 6 or 100 mg/kg vitamin E for 12 weeks. During this time, a total of 1532, 1464, and 1316 eggs were independently collected at weeks 8, 10, and 12, respectively, and subsequently stored for 0 or 14 d before hatching. The outcomes from three trials showed that prolonged egg storage time (14 vs. 0 d) negatively affected (p < 0.05) the egg characteristics, hatchability traits, and the yolk total antioxidant capacity (T-AOC) (p < 0.05). Chicks derived from the stored eggs exhibited higher malonaldehyde (MDA) and T-AOC in the serum and yolk sac (p < 0.05). Broiler breeder dietary vitamin E (100 vs. 6 mg/kg) increased (p < 0.05) the hatchability and the antioxidant status of the yolks as indicated by a higher α-tocopherol content and T-AOC and lower MDA level (p < 0.05). The supplementation of vitamin E also remarkably increased (p < 0.05) the total superoxide dismutase (T-SOD) activity (yolk sac, weeks 8 and 12) and T-AOC (serum, weeks 8, 10, and 12; yolk sac, weeks 8 and 12) and decreased (p < 0.05) the MDA content of chicks (yolk sac, week 10; serum, week 12). Interactions (p < 0.05) were found between the broiler breeder dietary vitamin E and egg storage time on the hatchability and antioxidant status of chick tissues. Broiler breeder dietary vitamin E (100 vs. 6 mg/kg) increased (p < 0.05) the hatchability and the T-AOC in the serum and liver of chicks, and decreased (p < 0.05) the early embryonic mortality and the MDA content in the yolk sacs of chicks derived from eggs stored for 14 d but not for 0 d. In conclusion, prolonged egg storage time (14 vs. 0 d) increased the embryonic mortality, decreased the hatchability, and impaired the antioxidant status of egg yolks and newly hatched chicks, while the addition of broiler breeder dietary vitamin E (100 vs. 6 mg/kg) could partly relieve these adverse impacts induced by long-term egg storage.