Survey of vitamin D metabolite levels during growth and development in Japanese quail.

Plasma calcium and vitamin D metabolite levels were monitored during growth and development in male and female Japanese quail. In male Japanese quail, plasma calcium levels were constant (range 9.0 to 10.9 mg/dl); the 1,25-dihydroxyvitamin D [1,25-(OH)2D] levels remained undetectable in all age groups. Plasma calcium levels in the females rose at 6 weeks of age and remained elevated. The female 1,25-(OH)2D levels increased from undetectable levels at 3 to 5 weeks to a peak of 297 pg/ml at 8 weeks and remained elevated at 12 weeks of age in ovulating birds. Twelve-week old female without an egg in their oviduct had plasma 1,25-(OH)2D levels similar to males and immature females. No marked changed occurred in plasma 25-(OH)D levels due to sex or age. Plasma 24, 25-(OH)2D levels stayed relatively constant at about 2 ng/ml for both male and females at all ages studied.