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 the three test diets containing either cellulose, freeze‐dried kiwifruit or kiwifruit fibre as the sole fibre source for 14‐day 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 because of 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 influence of fibre inclusion and transit time regulation on the performance, health status, microbial activity and population, physico-chemical characteristics of the hindgut digesta and intestinal morphology in early weaned pigs were examined. For these experiments, wheat bran (WB) was used as fibre source and loperamide as a drug (LOP) to increase the digesta transit time. In Expt 1, a total of 128 early weaned pigs were randomly distributed in a 2 £ 2 factorial combination of WB inclusion (0 v. 40 g/kg) and LOP administration (0 v. 0·07 mg/kg body weight) during 13 d. For Expt 2, a total of twenty-four piglets were allotted to three dietary treatments for 15 d with the same basal diet (control diet) as Expt 1; a diet with 80 g/kg of WB and the combination of WB and LOP. In Expt 1, LOP improved the average daily feed intake and average daily gain of the animals (P¼ 0·001 and 0·007, respectively). The same result was obtained when WB was combined with LOP. The WB -LOP group also showed a higher concentration of SCFA (P¼0·013), acetic acid (P¼ 0·004) and propionic acid (P¼ 0·093). On the other hand, WB inclusion reduced the organic matter and crude protein digestibility (P¼ 0·001) and tended to decrease the enterobacteria population (P¼ 0·089). In Expt 2, WB increased the butyric acid concentration (P¼0·086). We concluded that the inclusion of WB to modify the intestinal microbiota activity combined with LOP may be beneficial to animal health and performance.