IntroductionThis study aimed to evaluate the effects of a single-cell protein (SCP) source from Paecilomyces variotii on the apparent total tract digestibility (ATTD) of macronutrients and energy, diet palatability, fecal fermentative metabolites, and microbiota in dogs.Materials and methodsFive extruded diets containing 0, 4, 8, 12, and 16% of SCP were manufactured. To isolate the metabolizable energy (ME) and the ATTD of the SCP, an additional test diet was manufactured containing 80% of the 0