[Role of protein in control of the growing chick's appetite]

After a short study of the literature about the effect of proteins on the food intake regulation, the authors conclude that the only way to compare two feeds about their intake level consist in a comparison with animals of nearly the same live weight by expressing the intakes plotted against live weight. Themselves, they compare ingestions by chickens of rations which vary by their protein level and quality. In a first step, authors show that increasing the protein content of the ration led to a rise in the food intake, but then, beyond a critical level of protein, the food intake decreases gradually. In a second step, authors show that a better quality of the food protein leads to an increase on intake. In conclusion, proteins influence food intake not because they satisfy the nitrogen need of the animal, but because they saturate the blood in products coming from the catabolism of their non utilised fraction.