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

To determine the effect of a certain diet on the intestinal flora of chicks, the cecal flora of chicks fed on a low protein or low lysine diet was examined. The cecal flora of chicks fed on the low protein diet was similar to that of chicks fed on a normal protein diet, but the total count of bacteria, Eubacterium and Enterobacteriaceae in the cecal content of chicks fed on the low lysine diet containing a formulated amino acid mixture minus lysine was significantly lower than that of chicks fed on the control diet. The total count of Lactobacillus in the cecum was remarkably reduced by feeding the amino acid diet, especially the low lysine diet. Levels of most free amino acids in the cecal contents of the low protein group were significantly lower than those of the control. Lysine, leucine, phenylalanine, methionine, histidine, glycine and tyrosine of the cecal contents in the low lysine group were significantly lower than those of the control group.