Abstract: 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.

Key words: Weissella confusa; cholesterol-lowering; safety evaluation; antioxidant activity

摘要： 为筛选降胆固醇乳酸菌并评估其抗氧化活性，从娟姗及娟姗-和牛杂交犊牛摄入初乳前后的粪便样本中分离出45 株乳酸菌，通过16S rDNA序列分析鉴定出5 个属的菌株，包括台湾乳球菌（Lactococcus taiwanensis）、乳酸乳球菌（Lactococcus lactis）、唾液联合乳杆菌（Ligilactobacillus salivarius）、食窦魏斯氏菌（Weissella cibaria）和融合魏斯氏菌（Weissella confusa）。由于W. confusa JCM11和W. confusa JCF7降胆固醇能力较强，对其安全性、耐酸与耐胆盐能力及抗氧化能力进行测定。结果表明，W. confusa JCM11和W. confusa JCF7表现出显著的降胆固醇能力，胆固醇清除率分别达43.8%和43.4%。安全性评价显示，2 株菌均无溶血活性，对大肠杆菌、金黄色葡萄球菌和单核细胞增生李斯特菌均表现出显著的抑菌效果，在硝酸还原酶实验、吲哚实验和明胶液化实验中均表现为阴性。耐酸与耐胆盐实验表明，W. confusa JCM11和W. confusa JCF7在低pH值和高胆盐浓度下表现出较强的耐受性。抗氧化活性检测结果显示，2 株菌的发酵上清液均具有良好的抗氧化活性。综上所述，W. confusa JCM11与W. confusa JCF7不仅具备出色的降胆固醇能力与抗氧化活性，还具有良好的安全性及胃肠道适应性，这为功能性益生菌产品的开发提供了宝贵的菌种资源。

关键词: 融合魏斯氏菌；降胆固醇；安全性评价；抗氧化活性