THE RELATIONSHIP BETWEEN THE ALPHA-TOCOPHEROL CONTENT OF THE YOLK ANDITS 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 n ewly hatched chick was investigated. Four batches of fertile eggs (Ros s 1 broiler-breeder type) with mean yolk alpha-tocopherol concentratio ns (mu g g(-1) yolk) of 60.8, 155 3, 272.2 and 376.6 were incubated an d the levels of the vitamin in the liver, brain, heart and kidney of t he resultant chicks were measured. The liver of the day-old chick cont ained far higher levels of the vitamin than were found in the other ti ssues 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 proportion al to the levels initially present in the yolk. The concentrations of alpha-tocopherol exhibited by the heart and kidney were affected by th e initial yolk values but the response was not linear over the range o f yolk alpha-tocopherol concentrations studied. The results indicate t hat the initial concentration of alpha-tocopherol in the yolk has a pr ofound effect on the subsequent levels of this vitamin in the tissues of the chick. In a separate experiment, the changes in the concentrati on 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.