Rhythmic Responses of Chicks to Injected Thiamine , ,

Abstract

The growth of chicks fed diets suboptimum or adequate in thiamine took place mainly during the day, even though the laboratory was illuminated continuously. When suboptimum amounts of thiamine were injected, chick weight increased rapidly for a few hours, followed by a decline in weight. The duration and intensity of the “growth” phase varied with dosage, and was sufficient to overcome and to reverse the normal diurnal rhythm. Total growth varied with the frequency of injection; thiamine injected every other day was utilized less effectively than that injected daily or twice a day. Large injections were relatively wasteful.