The viability of the
freeze-dried bacteria, 1.051013 CFU/g, was determined by flow cytometry [11] and by plate counting on
MRS agar (de Man, Rogosa and Sharpe; MRS, Merck, Darmstadt). Commercial dry feed served as a basis
in which the various concentrations of bacteria were added, in 20 ml of sunflower oil, to commercial dry
feed followed by mixing with a blender.