# Effects of Dietary Vitamin C Supplementation on Vitamin C Synthesis, Transport, and Egg Deposition in Breeding Geese

## TL;DR

This study shows that adding vitamin C to geese diets increases vitamin C in their eggs by boosting absorption and reducing internal synthesis.

## Contribution

The study reveals how dietary vitamin C affects synthesis, transport, and deposition in geese eggs, identifying an optimal supplementation level.

## Key findings

- Dietary vitamin C increased serum and egg yolk vitamin C levels in geese.
- Vitamin C supplementation upregulated intestinal and ovarian transporters while suppressing hepatic synthesis enzymes.
- A 300 mg/kg vitamin C dose was found to be effective and practical for geese.

## Abstract

Vitamin C is an essential antioxidant that helps maintain the physiological balance in poultry. The nutrition of developing embryos, which relies on nutrients stored in the egg, significantly impacts poultry production. Unlike laying hens, geese have longer egg formation periods—approximately 10 to 12 days for yolk and about 3.5 to 4 h for albumen, which may favor vitamin C deposition in eggs. However, it has not yet been studied whether dietary vitamin C supplementation in breeding geese can effectively increase the vitamin C concentration in eggs. This study aims to investigate the effects of dietary vitamin C supplementation on vitamin C synthesis, transport, and egg deposition. The results demonstrated that dietary vitamin C elevated egg yolk and serum vitamin C levels, altered vitamin C transporter expression in intestines and ovaries, and suppressed synthesis-related enzymes in the liver and kidney. These findings indicate that exogenous vitamin C enhances intestinal absorption, inhibits hepatic synthesis, and promotes yolk deposition in geese.

This study aims to investigate the effects of dietary vitamin C supplementation on vitamin C synthesis, transport, and egg deposition in breeding geese. A total of 450 female and 90 male 221-day-old Yangzhou geese were randomly assigned to five treatment groups with six replicates each (15 females and 3 males per replicate). The control group received a basal diet, while the other four groups were fed diets supplemented with 100, 200, 300, and 400 mg/kg vitamin C over a 16-week feeding trial. The results showed that dietary vitamin C supplementation increased the vitamin C content in both serum and egg yolks and modulated the expression of key vitamin C-related genes. Specifically, the intestinal and ovarian sodium-dependent vitamin C transporters 1 and 2 (SVCT1/SVCT2) were upregulated, whereas hepatic and renal L-Gulonolactone oxidase (GLO) and SVCT1 were suppressed. These findings indicate that exogenous vitamin C enhances intestinal absorption, inhibits hepatic synthesis, and promotes yolk deposition, with 300 mg/kg emerging as an effective and practical supplementation level that provides a physiological basis for its application in poultry nutrition.