The relationship between the alpha-tocopherol content of the yolk and its accumulation in the tissues of the newly hatched chick

The effect of a range of concentrations of a-tocopherol in the initial yolk on the subsequent levels of this vitamin in the tissues of the newly hatched chick was investigated. Four batches of fertile eggs (Ross 1 broiler-breeder type) with mean yolk alpha-tocopherol concentrations (mu g g(-1) yolk) of 60.8, 155 3, 272.2 and 376.6 were incubated and the levels of the vitamin in the liver, brain, heart and kidney of the resultant chicks were measured. The liver of the day-old chick contained far higher levels of the vitamin than were found in the other tissues studied. The concentration of alpha-tocopherol in the liver was directly proportional to the initial level of this vitamin in the yolk. The concentrations of alpha-tocopherol in the brain were only about 1% of the corresponding liver values but were also directly proportional to the levels initially present in the yolk. The concentrations of alpha-tocopherol exhibited by the heart and kidney were affected by the initial yolk values but the response was not linear over the range of yolk alpha-tocopherol concentrations studied. The results indicate that the initial concentration of alpha-tocopherol in the yolk has a profound effect on the subsequent levels of this vitamin in the tissues of the chick. In a separate experiment, the changes in the concentration of alpha-tocopherol in the liver were studied over the first 9 days after hatching. The vitamin was found to be rapidly depleted from the liver after hatching.