alpha-tocopherol, beta-carotene, and retinol enrichment of chicken eggs

Due to the numerous health benefits associated with consumption of antioxidants such as alpha-tocopherol and beta-carotene, an experiment was conducted to determine dietary levels that would significantly enhance their concentration in chicken egg yolks. In the experiment, 127 Single Comb White Leghorn laying hens were divided into treatment groups (n = 40 per treatment group) and fed diets containing 0, 50, 100, 200, or 400 mg/kg beta-carotene, dl-alpha-tocopheryl acetate, or their combination. Yolk alpha-tocopherol increased (P < .05) from the control level of 144 micrograms/g of yolk to 477 micrograms/g of yolk when 400 mg dl-alpha-tocopheryl acetate/kg of diet was supplemented. Yolk retinol levels increased (P < .05) from 11.6 micrograms/g of yolk in controls to 13.9 micrograms/g of yolk at 200 mg beta-carotene/kg of diet. beta-Carotene content in the yolk also increased (P < .05) from .14 micrograms/g of yolk in controls to 5.19 micrograms/g of yolk at 200 mg beta-carotene/kg of diet. Supplemental beta-carotene markedly decreased the yolk deposition of alpha-tocopherol when the two compounds were fed together. Egg production, egg weight, and egg yield were not affected by dietary supplementations. Although the data indicated that it is possible to significantly increase the concentration of all three compounds in chicken eggs, because of the relative expense involved it may not be commercially viable to increase egg yolk concentrations of beta-carotene or retinol by supplementing beta-carotene in the diet.