Dietary vitamin C improves reproductive performance by increasing antioxidant capacity, steroid hormone concentration and expression of genes involved in steroid hormone synthesis in Yangzhou geese

1. This study aimed to evaluate the effects of dietary ascorbic acid (vitamin C) supplementation on the reproductive performance, follicular development, antioxidant capacity, serum steroid hormone concentration and expression of genes involved in steroid hormone synthesis in Yangzhou geese.2. A total of 540, 221-day-old geese (450 females and 90 males) were randomly divided into five groups that received different diets. Treatments included vitamin C levels of 0, 100, 200, 300 or 400 mg/kg, respectively.3. Dietary vitamin C supplementation led to a highly significant linear increase in laying rate (p < 0.01), with significant improvements detected at 300 mg/kg and 400 mg/kg (p < 0.01). Thus, within the supplement range of 0–400 mg/kg, graded additions of vitamin C linearly improved reproductive performance with economic benefits. In consideration of commercial breeding practices together with the observed physiological and productive indices, dietary vitamin C supplementation at 300 mg/kg was effective.4. Feeding 300 mg/kg prompted oestradiol and progesterone concentrations in both serum and hierarchical follicular yolks (p < 0.05) and the number of primordial follicles increased significantly (p < 0.01). This level of vitamin C in the feed resulted in elevated activity levels of total antioxidant capacity, superoxide dismutase and catalase in both serum and follicles, along with a reduction in malondialdehyde levels.5. Dietary supplementation with 300 mg/kg vitamin C increased the expressions of StAR, HSD3B1 and CYP11A1 in granulosa layer. Similar expression patterns of CYP17A1, CYP19A1, HSD3B1 and HSD17B1 were detected in the theca layer.