Aims: To investigate whether green kiwifruit modulates the composition of colonic microbiota in growing pigs. Methods and Results: Thirty two pigs were fed the control diet or one of three test diets containing either cellulose, freeze-dried kiwifruit or kiwifruit fibre as the sole fibre source for 14 days’ study. A Ward’s dendrogram of similarity cluster analysis on PCR-DGGE gels revealed that inclusion of freeze-dried kiwifruit and kiwifruit fibre into diets altered the bacterial community, indicating the presence of two distinct clusters. Quantification of different bacterial groups by qPCR demonstrated that pigs fed the freeze-dried kiwifruit or kiwifruit fibre diets had a significantly higher number (p<0.05) of total bacteria and Bacteroides group and a lower number of Enterobacteria and Escherichia coli group, as well as a greater ratio of Lactobacillus to Enterobacteria when compared to pigs fed the control or cellulose diets. Conclusions: Green kiwifruit, mainly due to fibre, modulated the colonic microbiota, leading to an improved intestinal environment in growing pigs. Significance and Impact of the Study: This is the first report regarding the effect of green kiwifruit on gut microbiota using the in vivo pig model. These results provide the first evidence of interaction between green kiwifruit and colonic microbiota. The report is from the Riddet Institute, Massey University, Palmerston North, New Zealand and the Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, Barcelona, Spain. Han KS, Balan P, Molist Gasa F, Boland M. Lett Appl Microbiol 2011. doi: 10.1111/j.1472-765X.2011.03012.x. [Epub ahead of print].