Abstract

Feline obesity is an increasingly prevalent health concern and is closely associated with metabolic disorders and intestinal dysbiosis. This study aimed to screen feline-derived lactic acid bacteria (LAB) for bile salt hydrolase activity, in vitro cholesterol-removal capacity, and selected probiotic-associated characteristics. Approximately 700 LAB isolates were obtained from fecal samples of healthy domestic cats and evaluated for bile salt hydrolase (BSH) activity, among which 105 isolates were identified as BSH-positive. Further screening was performed based on BSH activity, cholesterol-removal capacity, adhesion-related properties, antioxidant activity, gastrointestinal tolerance, antibacterial activity, organic acid production, hemolytic activity, and antibiotic susceptibility. Three candidate strains were ultimately selected and preliminarily identified by 16S rRNA gene sequencing as Enterococcus hirae C283, Ligilactobacillus animalis C289, and Enterococcus faecium C422. These strains exhibited BSH activity and preliminary in vitro cholesterol-removal phenotypes under the tested culture conditions, together with tolerance to simulated gastrointestinal conditions, antioxidant activity, antibacterial activity, and organic acid production. No hemolytic activity was detected; however, all three strains exhibited resistant or intermediate phenotypes to multiple antibiotics, highlighting the need for further genome-based safety assessment, particularly for the two Enterococcus strains. Overall, these findings identified feline-derived LAB candidates with BSH activity, preliminary in vitro cholesterol-removal phenotypes, and multiple probiotic-associated characteristics. However, these in vitro findings do not demonstrate regulation of host lipid metabolism or blood lipid levels. Comprehensive safety assessment, particularly for the Enterococcus strains, and in vivo validation are required before further application.

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