Vitamin E in cranes: reference ranges and nutrient interactions

Area of Science:

• Avian nutrition
• Wildlife health
• Nutritional biochemistry

Background:

• Fat-soluble vitamins A and E are crucial for avian health.
• Plasma concentrations of these vitamins can reflect nutritional status and environmental factors.
• Understanding vitamin levels in cranes is important for conservation and captive management.

Purpose of the Study:

• To measure plasma concentrations of vitamin E (alpha-tocopherol) and vitamin A (all-trans retinol) in various crane species.
• To investigate factors influencing vitamin levels, including age, sex, habitat, and diet.
• To establish baseline vitamin levels for captive and free-ranging cranes.

Main Methods:

• Plasma samples were collected from 274 captive and 5 free-ranging cranes of all 15 species.
• Vitamins E and A were quantified using established analytical methods.
• Statistical analyses were performed to assess differences based on age, sex, species, and habitat, and to explore dietary correlations.

Main Results:

• Captive cranes had higher mean plasma alpha-tocopherol (6.57 +/- 0.82 microg/ml) than migrating greater sandhill cranes (3.71 +/- 0.22 microg/ml).
• Temperate-dwelling crane species exhibited higher alpha-tocopherol levels than tropical/subtropical species; no significant age or sex effects were found.
• Plasma retinol levels did not differ significantly across groups; dietary vitamin E showed a logarithmic correlation with plasma alpha-tocopherol, and 0.5 mg/kg dietary selenium was linked to lower alpha-tocopherol.

Conclusions:

• Plasma vitamin E levels in cranes are influenced by geographic origin (habitat) and diet.
• Dietary vitamin E intake is a key determinant of circulating alpha-tocopherol concentrations.
• Selenium supplementation may warrant careful consideration due to its potential impact on vitamin E status in cranes.