Comparative immunomudulating effects of five orally administrated bifidobacteria species in male albino rats

Bifidobacteria belong to effective probiotics in preventing and reducing the severity of some diseases by modulating the host immune response. Each probiotic species is unique, and thus its properties and effects have to be assessed separately. We investigate here the effects of B.infantis, B.longum, B.adolescentis, B.bifidum, B.breve and B.bifidum on immune parameters of albino rats orally administrated a yogurt fermented with one of the five bifidobacteria species for 30 days. B.adolescentis (adult-type bifidobacteria) induced a significant increase in pro-inflammatory cytokine secretion (IL-1, IL-4, IL-12 and TNF-alpha) relative to B.breve and B.infantis (infanttype bifidobacteria). B.bifidum, B.longum and B.adolescentis induced significantly high levels of the anti-inflammatory IL-10. B.adolescentis stimulated and increased the release of antioxidant enzymes (SOD, glutathione and catalase), and also stimulated secretion of high levels of total serum Ig. All studied bifidobacteria species, particularly B. adolescentis, caused significant reduction of the number of the pathogenic bacteria. In conclusion, B. adolescentis is superior to the other studied species of bifidobacteria in enhancing immune parameters.