¹Kafkas University, Faculty of Veterinary Medicine, Microbiology Department, TR-36100 Kars - TÜRKİYE
²Siirt University, Faculty of Veterinary Medicine, Histology and Embryology Department, TR-56200 Siirt - TÜRKİYE
³Siirt University, Faculty of Veterinary Medicine, Food Hygiene and Technology Department, TR-56200 Siirt - TÜRKİYE DOI : 10.9775/kvfd.2026.37251 The term "microbiota," formerly known as "microflora," generally refers to bacterial communities found on mucosal surfaces or other parts of the body, such as the skin. The canine gut microbiota plays a critical role in host health and undergoes dynamic changes across life stages. This study aimed to isolate, screen, and presumptively characterize potential probiotic candidate bacteria from canine fecal samples obtained from puppy, young, and adult dogs. Fecal samples were collected from three healthy dogs in each of three age groups (nine dogs): puppies (<6 months), young dogs (6-18 months), and adults (>18 months). From an initial pool of approximately 1000 bacterial isolates, 90 Gram-positive, catalase-negative, and oxidase-negative isolates were selected after a multi-stage in vitro screening for tolerance to pH 2.0, resistance to 3% porcine bile, blood agar hemolysis, and growth under combined stress (pH 4.5 and 2.5% sodium cholate). Following functional and safety screening, 30 representative candidate strains (10 from each age group, selected via balanced randomization among eligible non-redundant isolates) were biochemically characterized using the VITEK® 2 GP system. Presumptively identified taxa belonged predominantly to lactic acid bacteria, including Lactiplantibacillus (Lactobacillus) plantarum, Enterococcus faecium, Pediococcus acidilactici, Limosilactobacillus (Lactobacillus) reuteri, Enterococcus faecalis, and Pediococcus pentosaceus, which were detected across all three age cohorts, as well as stage-associated taxa such as Lactobacillus acidophilus and Weissella confusa. Isolates exhibited distinct substrate utilization profiles, yielding 17, 16, and 10 positive reactions across variable markers in puppy, young, and adult groups, respectively. These findings establish a well-characterized strain collection and demonstrate that canine fecal microbiota harbors viable, stress-tolerant lactic acid bacteria with age-associated phenotypic profiles, providing candidate strains for future molecular confirmation and functional evaluation. Keywords : Animal probiotics, Canine intestinal microbiota, Lactic acid bacteria, Phenotypic characterization, Presumptive identification