Screening for Cholesterol-Lowering Lactic Acid Bacteria from Calf Feces and Their Antioxidant Activity

The aim of this study was to screen for lactic acid bacteria (LAB) with cholesterol-lowering capacity and to evaluate their antioxidant activity. In total, 45 strains of LAB were isolated from fecal samples of Jersey and Jersey × Wagyu calves before and after colostrum intake. By 16S rDNA sequence analysis, these strains were identified to belong to five genera, including Lactococcus taiwanensis, Lactococcus lactis, Ligilactobacillus salivarius, Weissella cibaria and Weissella confusa. Due to their strong cholesterol-lowering ability, W. confusa JCM11 and JCF7 were selected for evaluation of their safety, acid and bile salt tolerance, and antioxidant capacity. The experimental results demonstrated that W. confusa JCM11 and JCF7 removed 43.8% and 43.4% of cholesterol, respectively. Safety assessments showed that both strains were non-hemolytic, exhibited significant antibacterial activity against Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes, and tested negative in nitrate reductase, indole, and gelatin liquefaction tests. W. confusa JCM11 and JCF7 were highly tolerant to low pH and high bile salt concentrations. The fermentation supernatants of both strains showed good antioxidant activity. In conclusion, W. confusa JCM11 and JCF7 possess remarkable cholesterol-lowering and antioxidant activity along with excellent safety and gastrointestinal tolerance, making them valuable microbial resources for the development of functional probiotic products.