Yoghurt accelerates the recovery of defence mechanisms against Streptococcus pneumoniae in protein-malnourished mice

• Published in: British journal of nutrition 2006-03, Vol.95 (3), p.591-602
• Main Authors: Villena, Julio, Racedo, Silvia, Agüero, Graciela, Alvarez, Susana
• Format: Article
• Language: English
• Subjects: Acids; animal disease models; Animal models; Animals; Antibodies, Bacterial - analysis; Bacteria; bacterial pneumonia; Biological and medical sciences; Bronchoalveolar Lavage Fluid - immunology; Colony Count, Microbial; Defense; Diet; experimental diets; Experiments; Feeding. Feeding behavior; food intake; Fundamental and applied biological sciences. Psychology; health foods; Immunoglobulin A - analysis; Immunoglobulin G - analysis; immunostimulants; lactic acid bacteria; Leukocyte Count; Lung - immunology; Lung - microbiology; macrophage activation; macrophages; Male; Malnourished mice; Malnutrition; Mice; Mortality; Neutrophils - immunology; Nutrition research; nutritional intervention; Phagocytosis - immunology; Pneumococcal Infections - immunology; Pneumococcal Infections - pathology; pneumonia; Probiotics; Probiotics - therapeutic use; protein energy malnutrition; Protein-Energy Malnutrition - immunology; Protein-Energy Malnutrition - microbiology; Proteins; resistance mechanisms; respiratory infection; Respiratory infections; Respiratory Tract Infections - immunology; Respiratory Tract Infections - microbiology; Streptococcus infections; Streptococcus pneumoniae; Vertebrates: anatomy and physiology, studies on body, several organs or systems; weanlings; Yoghurt; Yogurt
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1079/BJN20051663

Experiments studied the effect of yoghurt on the recovery of defence mechanisms against Streptococcus pneumoniae respiratory infection in malnourished mice. Weaned mice were malnourished with a protein-free diet (PFD) for 21d. Malnourished mice were made replete with a balanced diet (BD), yoghurt, or the BD with supplemental yoghurt (BD+Y) for 7, 14 or 21d. The normal control (NC) group was fed the BD whereas malnourished control (MC) mice consumed only the PFD. Mice were challenged with pneumococci at the end of each dietary treatment. MC mice showed increased susceptibility to pneumococcal infection. Blood leucocytes, phagocyte activity and serum and bronco-alveolar anti-pneumococcal IgG and IgA were significantly lower in the MC than in the NC group. Repletion of malnourished mice with the BD for 21d was necessary to obtain a response to infection similar to that of NC mice; however, administration of the BD+Y for 14d was enough to normalise the immune defence mechanisms. Histological examination of MC lungs showed progressive loss of alveolar architecture. Lung injuries were significantly less pronounced in NC mice. Mice treated with the BD+Y for 14d showed histological signs similar to the NC group. The present study showed that administration of yoghurt to malnourished mice induced an early recovery of the immunological parameters studied. Despite the uncertainties about the mechanisms involved and about the human relevance of the effects observed in animal models, the present study provides a strong rationale for the hypothesis that yoghurt consumption by malnourished hosts will accelerate the recovery of the immune mechanisms involved in the protection against respiratory infections