Effects of zinc and Bacillus subtilis on the reproductive performance, egg quality, nutrient digestion, intestinal morphology, and serum antioxidant capacity of geese breeders

The effects of zinc (Zn) and Bacillus subtilis (B. subtilis) on reproductive performance, egg quality, nutrient digestion, intestine morphology, and antioxidant capacity were explored in geese breeders. Geese breeders (n = 120, 46-wk of age) were randomly assigned into 6 groups with 4 replicates of 5 birds each (1 male and 4 female). Breeders were fed diets with 2 levels of B. subtilis (2.5 × 109 and 5 × 109 CFU/kg) crossed with three levels of Zn (25, 45, and 65 mg/kg) for duration of 10-wk. The results showed that the egg laying rate (P < 0.05), fertility rate (P < 0.01), hatchability rate (P < 0.05), yolk color (P < 0.05), and the retentions of crude protein (P < 0.05), ether extract (P < 0.05) and phosphorus of geese breeders were improved by dietary supplementation of 5 × 109 CFU/kg B. subtilis and 25 mg or 45 mg/kg Zn. The serum T-SOD (P < 0.05) was increased by 45 mg/kg Zn supplementation. The serum T-AOC (P < 0.05) and retention of Zn (P < 0.05) were increased by 5 × 109 CFU/kg B. subtilis supplementation. The birds fed with 5 × 109 CFU/kg B. subtilis and 25 mg or 45 mg/kg Zn showed improved villus length (P < 0.01) and villus length/ crypt depth (P < 0.01) in both the jejunum and ileum. In conclusion, the combination of B. subtilis and Zn may have synergistic effects on these parameters, and dietary inclusion of 5 × 109 CFU/kg B. subtilis and 45 mg/kg Zn is recommended for improving the reproductive performance of geese breeders.