Which of the following is not a function of gut flora

If the intestinal microbes are eliminated, the intestinal contents become voluminous, the caecum is dilated and the intestine remains thinly walled. Historically, in germ-free animals, the villi are shoer, epithelial cell turnover is reduced and gut-associated lymphoid tissue is atrophic. From a functional point of view, in the absence of flora, mucosal disaccharidase activity is increased and nutrient absorption is more efficient, but gastric and intestinal motility is slower, and immunological defense mechanisms are weaker. Regarding infections, the protective influence of intestinal microflora extends beyond the gut. Through an ill-understood mechanism, normal enteral flora protects also against parenteral infections. Bowel flora has also been given the credit for synthesizing several vitamins. These vitamins include vitamin K, cyanocobalamin, folate, pyridoxine, biotin, pantothenate, and riboflavin. Anaerobic bacterial fermentation of fiber in the colon results in the formation of water, carbon dioxide, hydrogen, and sho-chain fatty acids such as acetic, propionic, and butyric acids.