Differential Effects of Cooked Beans and Cooked Lentils on Protein Metabolism in Intestine and Muscle in Growing Rats

Abstract

Aims: The effect of diets based on cooked beans or lentils on protein metabolism in intestines and muscles was studied in rats. Method: The cooked seeds were used as the unique protein source in balanced diets (containing 229 and 190 g of crude protein per kg dry matter) fed to young growing rats for 20 days. Their effects were compared with those of the control casein diet in pair-fed rats. Protein synthesis rates in small and large intestines and in gastrocnemius and soleus muscles were determined in vivo, in a fed state, by the flooding dose method, using ¹³C-valine. Results: In the small and large intestine tissues of the legume fed groups, protein, RNA relative masses (mg·100 g BM^–1) and protein synthesis rates (FSR and ASR) were higher than in the control rats (p < 0.05). In gastrocnemius and soleus muscles,protein and RNA contents (in mg) and protein synthesis rates were significantly (p < 0.05) lower in the legume-fed groups than in the control rats. Conclusion: The chronic intake of cooked legumes increased protein synthesis rates in intestinal tissues and decreased them in muscles. This effect was greater for beans than for lentils in the large intestine and in gastrocnemius muscle.