Lactulose: effect on apoptotic- and immunological-markers in the gastro-intestinal tract of pre-ruminant calves

The study was conducted to elucidate the effects of orally administered lactulose in combination with Enterococcus faecium on immune response of the intestinal tract in pre-ruminant calves. The mRNA expression of pro- and anti-inflammatory cytokines and proliferation and apoptosis markers were investigated in jejunum, ileum, colon and caecum. Simmental calves were fed diets containing 1% (L1) or 3% (L3) lactulose and the probiotic strain of the genus E. faecium, and compared with a non treated control group. Primarily the high dose feeding with lactulose showed an effect on several mRNA gene expression parameters. In the jejunum a down-regulation of the anti-apoptotic marker Bcl-xl was determined and IL-10 mRNA gene expression was 2.6-fold up-regulated (P < 0.05). In the colon a 1.9-fold (P < 0.05) up-regulation of IL-10 and only in caecum an about 2-fold increase of TGF-β1 (P < 0.05) was found for both lactulose feedings. Caspase 3 was up-regulated in caecum only in the 3% lactulose treated group (P < 0.05). The enhanced apoptotic rate of caspase 3 seems to be associated with a decrease in crypth depth due to lactulose supplementation. The results indicated that mainly the high 3% lactulose dose in probiotic-fed calves has an affect on the intestinal immune function and on diverse apoptotic markers.