Fructo-oligosaccharides(FOS) have been studied extensively as a new feed additive in the past years.Many researches indicated that FOS could influence the balance of the intestinal micro-ecosystem,improve the ability of healthy intestinal microbial-ecosystem competition aginst enteric pathogens,resist the adhesion of the potential intestinal pathogen,and enhance the metabolism and economic efficiency.This article was aimed to elaborate the biological roles,nutrition physiological function of FOS in the in...