THE INHIBITORY EFFECT OF CARBOXYMETHYLCELLULOSE WITH HIGH-VISCOSITY ON LIPID ABSORPTION IN BROILER-CHICKENS COINCIDES WITH REDUCED BILE-SALT CONCENTRATION AND RAISED MICROBIAL NUMBERS IN THE SMALL-INTESTINE

Two diets, with or without a nonfermentable carboxymethylcellulose (CM C) with high viscosity, were fed to broiler chickens beginning at 2 wk of age to study whether the anti-nutritive effect of gelling fibers o n Lipid digestibility maybe associated with reduced intestinal bile sa lt concentration. Moreover,the microflora were examined to study wheth er possible changes in bile salt concentration coincide with alteratio ns in microbial numbers. Carboxymethylcellylose depressed apparent lip id digestibility (P = 0.021). Feed intake and weight gain were not sig nificantly:affected. Water intake was increased in birds fed the CMC d iet (P = 0.039). Bile acid concentration in small intestinal digests w as decreased (P = 0.047) in birds fed the CMC diet, which may have bee n caused by the increased water content of digesta (P < 0.001). The co ncentration of bile acids per gram dry matter or per milligram chromiu m was not reduced in small. intestinal contents. Broiler chickens fed the CMC diet excreted more bile acids in the excreta (P < 0.001). Tota l aerobic and anaerobic microbial counts in the intestinal digesta wer e Significantly increased in the duodenum plus jejunum (P = 0.038) but not in the ileum. Significant increases were found in the numbers of Clostridia (P = 0.017), Lactobacillus (P = 0.009), Bacteroides (P = 0. 022), and yeasts and molds (P 0.012). The present study supports the h ypothesis that a nonfermentable gelling fiber (CMC) decreases apparent lipid digestibility by reducing the concentration of bile acids in th e chyme in broiler chickens. Moreover, the ingestion of gelling fibers may increase the bacterial activity in the small intestine, which may further contribute to malabsorption of lipids.