Tocopherol absorption and metabolism in the chick and turkey

Area of Science:

• Animal Nutrition
• Nutritional Biochemistry
• Poultry Science

Background:

• Tocopherol (vitamin E) is an essential nutrient for poultry health.
• Differences in tocopherol metabolism between chickens and turkeys are not fully understood.
• Poultry require adequate vitamin E for growth, immunity, and meat quality.

Purpose of the Study:

• To compare tocopherol absorption, metabolism, and excretion in chickens and turkeys.
• To investigate the role of tocopheryl glucuronides in tocopherol bioavailability.
• To correlate dietary tocopherol levels with plasma and tissue concentrations in both species.

Main Methods:

• Chickens and turkeys were fed diets supplemented with varying levels of tocopherol for 28 days.
• Radio-labeled [3H]tocopherol and 141Ce were administered during the final 4 days of the study.
• Tocopherol levels, metabolites (glucuronides, quinone), and excretion were analyzed in plasma, liver, and intestinal contents.

Main Results:

• Plasma and liver tocopherol concentrations were significantly lower in turkeys compared to chickens.
• Tocopherol disappearance (absorption + catabolism) between feed and lower ileum was similar in both species (78-90%).
• Turkeys excreted 2.5- to 7-fold more tocopheryl glucuronides than chickens, with limited intestinal reabsorption.

Conclusions:

• Higher excretion of tocopheryl glucuronides in turkeys contributes to their lower plasma and tissue tocopherol concentrations.
• Tocopherol metabolism and excretion pathways differ between chickens and turkeys, impacting vitamin E bioavailability.
• Understanding these differences is crucial for optimizing vitamin E supplementation in poultry diets.