Effect of a non-lethal High Pressure Homogenization treatment on the in vivo response of probiotic lactobacilli.

Low levels of High Pressure of Homogenization (HPH) can be applied directly to lactic acid bacteria cells in order to enhance some functional properties. In a previous work we observed that a 50 MPa HPH treatment increased Lactobacillus paracasei A13 hydrophobicity and resistance to simulated gastric digestion. The aim of this work was to assess the in vivo effects of HPH treatment applied to probiotic lactobacilli on their interaction capacity with the gut and on their ability to induce IgA cell proliferation in mice intestine. BALB/c mice received FITC-labelled cultures of strains, previously treated or not (control) at 50 MPa. Fluorescently labelled cells were studied in the intestine of animals sacrificed 10 and 30 min after intragastric intubation. HPH-treated and control cultures of each strain were orally administered to mice for 2, 5 or 7 consecutive days. The number of IgA-producing cells in the gut was studied by immunohistochemistry. HPH treated probiotic lactobacilli modified their interaction with the small intestine. HPH-treated cells induced a higher IgA response compared to untreated ones, in a strain- and feeding period-dependent way. HPH treatment could increase some in vivo functional characteristics of probiotic strains, highlighting the potential of this technique for the development of probiotic cultures.