Immunobiotic Lactobacillus rhamnosus Isolated from Goat Milk, Enhances Systemic and Respiratory Innate Immune Response in Malnourished Mice

JULIO VILLENA; HÉCTOR MATÍAS HERRERA; SUSANA SALVA; NATALIA PAOLA BARBIERI; SUSANA ALVAREZ

Pingtung, Taiwan

Congreso; The 14th AAAP Animal Science Congress; 2010

Asian-Australasian Association of Animal Production Societies

Lactobacillus rhamnosus CRL1505 (Lr) strain isolated from goat milk from northwestern Argentina is able to improve resistance of malnourished mice against Streptococcus pneumoniae (Sp) infection. In this work, we studied the effect of Lr on the innate immune response against Sp. Malnourished mice received a balanced conventional diet (BD) or BD supplemented with Lr (108 cells) (BD+Lr) during 7 days. On day 8, these well-nourished (WNC) and malnourished (MNC) control mice were infected with Sp (105 cells) nasally. We analyzed in bronchoalveolar lavages (BAL), blood (B) and bone marrow (BM): a) leukocytes number, b) phagocytic activity, c) Gr1 and CD34 expression by flow cytometry, and d) BAL and serum IL-6 and TNF-α levels. Malnutrition decreased the number of granulocytes in both B and BM, being the mature myeloid cells (Gr1high) the main population responsible for this reduction. In addition, MNC mice showed decreased neutrophils peroxidase activity. BD+Lr treatment was able to normalize the number of B and BM Gr1high cells and improved neutrophils peroxidase activity. After challenge with Sp, there was an increase of the number of respiratory phagocytes in all the experimental groups. However, MNC mice showed impaired respiratory phagocytic activity and neutrophils recruitment into the lungs. Infection increased Gr1+ cells in B and BM. However, in MNC and BD groups it was observed an increase of BM Gr1high cells, while in WNC and BD+Lr mice there was an increase of BM Gr1low cells. Similar results were observed in the number of BM Gr1+CD34+ immature myeloid cells. In addition, BD+Lr treatment induced the normalization of IL-6 and TNF-α levels in response to Sp infection. We demonstrated that immunobiotic Lr is able to induce an early recovery of myeloid cells in B and BM of MNC mice. This effect is probably related with the improved innate immune response against Sp. In previous work, we found that L. rhamnosus CRL1505 has optimal technological properties and can be used to produce a high quality fermented goat milk. This fact and the present results strongly suggest that this strain could be used in the development of probiotic fermented goat milk, which would be especially useful for the recovery of immunocompromised hosts.