[Changes in the cAMP content in the intestinal and liver tissue and in 35S-thiamine transport in chickens fed a low-protein diet].

An experiment was carried out with 45 male broiler birds divided into three groups: I (controls), given a full-diet ration with 22.16 per cent protein; II, given a ration with 18.12 per cent protein; and III, fed a ration with 14.14 per cent protein. The chickens were given the respective ration mixture up to the age of 35 days. It was found that the group treated with the lowest amount of protein showed dependably lower absorption of 35S-thiamine as compared to the control group. The lower intake of dietary protein (groups II and III) was found to produce a negative effect on thiamine phosphates and the total and free thiamine in the liver. Protein deficiency led to a reliable drop of the cyclic adenosine 3', 5'-monophosphate in the jejunal mucosa and the liver tissue. The lower intake of protein with the ration produced an unfavourable effect on the respiratory activity of the intestinal mucosa. The birds of group III showed considerable disturbances in the ultrastructure of enterocytes. Discussed is the relation between the amount of dietary protein and the changes in the cAMP content and the 35S-thiamine absorption in the small intestine.