The mammalian gastrointestinal(GI) tract habors a dense and complex microbiota, which plays an important role in nutrition,immunity and physiology of host.More attention should be paid to the study on the GI microbiota of piglet since it will suffer the special physiological phase like early-weanlng.This present study was carried out to investigate the changes of microbioia in GI tract of piglets from 7 to 35(two weeks after weaning) days of age by using 16S ribosomal RNA(rRNA) gene based molecular me...