Disruption in stable establishment of commensal gut microbiota by early weaning is an important factor in susceptibility of young animals to enteric disorders. The artificial sweetener SUCRAM [consisting of neohesperidin dihydrochalcone (NHDC) and saccharin] included in piglets' feed reduces incidence of enteric disease. Pyrosequencing of pig caecal 16S rRNA gene amplicons identified 25 major families encompassing seven bacterial classes withBacteroidia,ClostridiaandBacillidominating the microbiota. There were significant shifts in microbial composition in pigs maintained on a diet containing SUCRAM, establishing SUCRAM as a major influence driving bacterial community dynamics. The most notable change was a significant increase ofLactobacillaceaepopulation abundance, almost entirely due to a single phylotype, designatedLactobacillus4228. The sweetener-induced increase inLactobacillaceaewas observed in two different breeds of pigs signifying a general effect. We isolatedLactobacillus4228, sequenced its genome and found it to be related toLactobacillus amylovorus.In vitroanalyses ofLactobacillus4228 growth characteristics showed that presence of NHDC significantly reduces the lag phase of growth and enhances expression of specific sugar transporters, independently of NHDC metabolism. This study suggests that sensing of NHDC by a bacterial plasma membrane receptor underlies sweetener-induced growth of a health promoting gut bacterium.