Differential effects of cooked beans and cooked lentils on protein metabolism in intestine and muscle in growing rats.

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.

Differential effects of cooked common bean (Phaseolus vulgaris) and lentil (Lens esculenta puyensis) feeding on protein and nucleic acid contents in intestines, liver and muscles in rats.

AIM: Our aim was to investigate the influence of legume feeding on the protein and nucleic acid content of intestinal tissues and muscles. METHODS: Growing male Wistar rats were fed ad libitum on balanced diets containing cooked common bean or lentil as the unique protein source (180 g.kg(-1) dry matter) for 20 days. The control group was pair-fed with an iso-energetic, iso-nitrogenous balanced casein diet. RESULTS: Intestinal tissues were heavier in the legume-fed groups and higher relative mass (g per 100 g body mass) of protein, RNA and DNA were found in these tissues as compared to those of the control groups. In liver protein and RNA masses were significantly lower in the bean group than in the control group but the DNA content was not different in the legume and in the control groups. In gastrocnemius and soleus muscles, there was no significant effect of legume feeding on the fresh mass and on the protein and RNA contents, but the DNA content of the m. gastrocnemius was significantly lower in both legume groups than in their control group. The ribosomal capacity of intestines, liver and muscles was not significantly affected by legume feeding. CONCLUSION: Legume feeding had a trophic effect on both proximal and distal intestinal tissues; dietary fiber appears to be the main cause of this effect.

Differential effect of lentil feeding on proteosynthesis rates in the large intestine, liver and muscle of rats.

The aim of this work was to test the hypothesis that the trophic effect of lentil feeding on large intestine results from a stimulation of protein synthesis and to determine whether it interferes with protein metabolism in other splanchnic or peripheral organs. Two groups of growing Sprague Dawley male rats were pair-fed iso-caloric iso-nitrogenous balanced diets containing either cooked lentils (Lens esculenta puyensis) or casein as unique protein source. Protein synthesis rates were measured in vivo, in large intestine, liver and gastrocnemius at the postprandial state. In large intestine, protein and ribonucleic acid contents were higher in the lentil-fed group than in the control group, and the amount of proteins synthesized was also higher (+57%). By contrast, liver protein and ribonucleic acid contents as well as protein synthesis rates were significantly lower in the lentil-fed group than in the control group. In the gastrocnemius muscle protein and ribonucleic acid contents were significantly lower and the amount of protein synthesized was also lower (-18%) in the lentil fed group than in the control group. This study suggests that stimulation of protein synthesis in the large intestine is compensated for by a decrease in liver and muscle.