Age-related effects of the probiotic bacterium Lactobacillus plantarum 299v on gastrointestinal function in suckling rats

The effect of a probiotic bacterium on gut function was studied in neonatal animals by using a model with suckling rats. Lactobacillus plantarum 299v (Lp299v) or saline (controls) was fed (3.0 x 10(6) CFU/g b.wt per day) for one week to rats aged either 3, 7 or 14 days, after which bacterial colonization, gut growth, and functional parameters were analyzed. In rats fed with Lp299v from 3 to 10 days of age, an increase in ceacal lactobacilli was correlated with reduced intestinal macromolecular permeability and increased mucosal protein compared to age-matched controls. Pups treated from 7 to 14 days of age showed a decrease in pancreas weight and protein content, whereas pups treated from 14 to 21 days of age showed little effect of the Lp299v treatment. The results indicated that the bacterial exposure affected the gut function, where the effects were age-related and the youngest rats appeared most sensitive.