Effect of fructo-oligosaccharides and different doses of Bifidobacterium animalis in a weaning diet on bacterial translocation and Toll-like receptor gene expression in pigs.
OBJECTIVE
Our aim was to study the possible synergic action of one prebiotic with increasing dietary doses of a probiotic strain of Bifidobacterium animalis on the translocation of bifidobacteria and on Toll-like receptor (TLR) gene expression in different organs of weaned piglets.


METHODS
Sixty-four pigs, reared from 21 to 35 d of age, were fed eight different diets according to a 2 x 4 factorial design: a control diet or the control diet supplemented with three different levels of B. animalis (10(7), 10(9), 10(11) colony-forming units/d), crossed with 0% or 2% sugar beet fructo-oligosaccharides. Pigs were then sacrificed, and the jejunum mucosa, ileocecal lymph nodes, and liver were sampled to determine the presence of Bifidobacterium spp. DNA and to quantify the expression of TLR2-, TLR4-, and tumor necrosis factor-alpha-encoding genes.


RESULTS
We found Bifidobacterium spp. genus-specific DNA in lymph nodes of subjects from all dietary treatments, including the control diet, but it increased with the bifidobacteria oral dose (P = 0.065). The linear effect of the dose of B. animalis on the expression of the TLR2-encoding gene in the lymph nodes was observed when fructo-oligosaccharides were added to the diet (P < 0.05). Tumor necrosis factor-alpha-encoding gene expression was positively correlated with TLR4- and TLR2-encoding gene expressions (P < 0.001 and P < 0.01, respectively) and negatively correlated with bifidobacteria DNA (P < 0.05). Moreover, the expression of the TLR4-encoding gene showed a positive correlation with TLR2-encoding gene expression (P < 0.001). In contrast, there was no correlation between expressions of the TLR2- and TLR4-encoding genes with the bifidobacteria DNA.


CONCLUSIONS
Soon after weaning, the translocation of the commensal bacteria in the ileocecal lymph nodes is a physiologic process. Moreover, diet affects the expression of the TLR2-encoding gene.
Trevisi
Paolo
P
Department of Agro-Food Protection and Valorisation, University of Bologna, Reggio Emilia, Italy. pablo.trevisi@unibo.it
De Filippi
Sara
S
Minieri
Laura
L
Mazzoni
Maurizio
M
Modesto
Monica
M
Biavati
Bruno
B
Bosi
Paolo
P
D000818:Animals; D000831:Animals, Newborn; D018988:Bacterial Translocation / Q000187:drug effects* / Q000502:physiology; D001644:Bifidobacterium / Q000254:growth & development*; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D007413:Intestinal Mucosa / Q000382:microbiology; D008099:Liver / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology; D009844:Oligosaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D019936:Probiotics / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D013552:Swine; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis / Q000235:genetics; D051193:Toll-Like Receptors / Q000096:biosynthesis / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014886:Weaning
D004269:DNA, Bacterial; D009844:Oligosaccharides; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; C116580:fructooligosaccharide