Animal Nutrition and Feed Technology

Wan, X.L., Zheng, X.C., Dai, H., Liang, J.R., Yang, H.M. and Wang, Z.Y. 2023. Effects of graded levels of dietary vitamin A supplementation on reproductive performance in geese. Animal Nutrition and Feed Technology, 23: 77–86.

A 28 weeks experiment was conducted to investigate the effects of vitamin A (VA) on reproductive performance of Geese. A total of 75 female and 15 male, 180 d old healthy Yangzhou geese were allocated to five treatment groups (15 female geese and 3 male geese each). The geese in the five groups were fed the basal diet supplemented with 0 (control), 4000, 8000, 12000, and 16000 IU/kg VA, respectively. The fertility, hatchability of fertile eggs, hatchability of settable eggs, and percentage of healthy day-old goslings were increased linearly and quadratically with increasing dietary VA supplementation (P<0.05). At the end of 8^th and 20^th week, dietary VA linearly increased serum progesterone concentration, and linearly and quadratically increased serum estradiol (E2) concentration (P<0.05). However, at the end of 28^th week, dietary VA addition decreased serum E2 concentration (P<0.05). The mRNA levels of gonadotropin releasing hormone, luteinizing hormone, estrogen receptor 1, and estrogen receptor 2, and follicle stimulating hormone receptor were linearly and quadratically increased by increasing dietary VA level (P<0.05), and a-follicle stimulating hormone was increased linearly by dietary VA supplementation. In conclusion, various dietary VA supplementations improved the reproductive performance of breeder geese, and the positive effects were associated with the regulation of genes in hypothalamic-pituitary-gonadal (HPG) axis. In this study, the recommended VA supplementation level in breeder geese diet was 12000IU/kg.