SEGREGATED INTAKE OF PROTEIN-RICH AND PROTEIN-FREE DIETS IN 2 MEALS A DAY - ITS EFFECT ON GROWTH AND VITAL FUNCTIONS IN RATS

Growing rats meal-fed for 4 weeks with a 20% or 40% casein diet in the morning (9:00-11:00) and a non-protein diet in the evening (19:00-21:00), or vice versa, were examined for growth and metabolic changes. A pair of groups given the 40% casein diet at one meal and the protein-free diet at the other meal, although becoming a little different from each other in growth, did not significantly differ from the control given only the 20% casein diet at the two meals. A pair of groups alternately given the 20% casein and protein-free diets, although excelling in protein efficiency ratio, were far inferior in growth to the groups given the 40% casein diet at either of the two meals. In any case, the rats with alternation of the diets sufficient and deficient in protein preferred the 20% or 40% casein diet to the protein-free one at whichever feeding time, and had a higher body weight gain when the casein diet was administered in the evening. The differences among these groups in protein intake throughout the experimental period were roughly reflected in their growth curves. A similar tendency was also observed for the blood urea level and hepatic serine dehydratase activity. As to the individual free amino acids in the plasma, however, there was no significant difference between the control and other groups except for a few amino acids (Ser, Gly and Phe).