الكاتب: Multiple References

Levels in Ghezel Sheep: The present study was conducted to investigate the variations in blood serum and hepatic levels of vitamin A and β- carotene in Ghezel sheep throughout the year. From 1000 sheep aged 1-5 years, blood and liver samples were collected before and after slaughter. The levels of vitamin A and β-carotene in both samples were determined spectrophotometrically. The results showed significant differences between summer and winter values (P < 0.05), but no differences were found between the sexes (P > 0.05). There were significant correlations between the vitamin A levels in serum and the liver (P < 0.05). Due to low levels of vitamin A and β-carotene in Ghezel sheep during the winter, supplementary feeding of vitamin A is recommended during this season.