Interrelationship between vitamin a and the thyroid of growing chicke

The effects of vitamin A level in the ration of Faryoumi chicken on growth, general metabolism, thyroid function and blood picture has been investigated. ror this purpose hundredone-day old, Fayoumi chicks were obtained fran the Poultry organization Hatching Station at Tanta. These chicken were divided into three groups and kept in a brooder for eightweeks. One group w~s kept as control and received 20000 U.U.of vitamin A palmitate (Pfeizer) per kilogram of the ration which represented 100% of the nutritional requirements. The second group of ch l ck en received a rat ion containing 40000 I.U. of vitamin ~ palmitate per kilogram. Tbi.&. represented 200% of theThe third group of chicken received a vitamin A deficient diet. Eachbird was injected subcutaneously with 5 microcuries of r131 (contained in 0.5 ml saline) one week before the end ofexperiment. The chicken were slaughtered after, three, fiveseven days from admini stration of the isotop.Blood was collected using EDTA as anticoagulant, for the assessment ofthe erythrocytic values. The thyroids were dis sected and their radioactivity was measured.