Influence of diets low in protein or lysine on the cecal flora of rats with reference to cecal contents.

To determine the effect of a certain diet on the intestinal flora of rats, the cecal flora of rats fed a low protein or low lysine diet was examined. Total counts of bacteria in the cecal contents of rats given the four kinds of diet (a normal protein diet, a low protein diet, a normal lysine diet and a low lysine diet) were not significantly different. The counts of Streptococcus, Enterobacteriaceae, and Clostridium perfringens in the cecal contents from rats fed the low protein diet were significantly lower than those from rats fed the normal protein diet. The count of Lactobacillus in the cecal contents of the low protein group were significantly lower than those of the control. But no significant difference was found between the levels of most of the free amino acids in the cecal contents of the low lysine group and those of the control group.