罗非鱼源肠道益生菌的分离鉴定及其体外益生特性分析

为了筛选出优良的鱼源益生菌，作者以吉富罗非鱼(Oreochromis niloticus)为实验材料，进行肠道芽孢杆菌和乳酸菌的分离、鉴定，并对分离得到的菌株进行抑菌活性、耐酸性、耐胆盐、人工胃肠液耐受、溶血活性和抗生素敏感性等体外益生特性分析。结果表明，从罗非鱼肠道中共分离得到109株菌，其中包括79株乳酸菌和30株芽孢杆菌，经过一系列的实验最终筛选出3株乳酸乳球菌（Lactococcus lactis）。生物学特性研究表明，3株菌均无溶血活性，对抗生素具有一定的敏感性，对强酸、胆盐和人工胃肠液具有一定的耐受性，对水产病原菌具有不同的抑菌活性。筛选得到的3株菌丰富了鱼源益生菌资源，它们均可作为优良的鱼源益生菌候选菌株。其中，菌株R1对强酸和人工胃肠液耐受性最强，菌株R29耐胆盐能力最强，可进行进一步的益生特性研究，挖掘其作为食品源益生菌的益生效果。

Isolation and Identification of Intestinal Probiotics from Tilapia Fish (Oreochromis niloticus) and in vitro Probiotic Characteristics Assessment

To select excellent probiotics of fish origin, tilapia fish (Oreochromis niloticus) was used as the experimental material to isolate and identify intestinal Bacillus and lactic acid Bacteria. The isolated strains were subjected to in vitro probiotic characteristics analysis, including antibacterial activity, acid tolerance, bile salts tolerance, artificial gastrointestinal fluid tolerance, hemolytic activity, and antibiotic susceptibility. The results showed that a total of 109 strains were isolated from tilapia fish intestine, including 79 strains of Lactobacillus and 30 strains of Bacillus. After a series of experiments, three strains of Lactococcus lactis were finally screened out. Biological characteristic studies indicated that all three strains exhibited no hemolytic activity. They showed a certain level of sensitivity to antibiotics and displayed tolerance to strong acids, bile salts, and artificial gastrointestinal fluids. Moreover, they demonstrated different antibacterial activities against aquatic pathogens. The three selected strains enriched the probiotic resources derived from fish, making them excellent candidates for fish-derived probiotics. Among them, strain R1 exhibited the highest tolerance to strong acids and artificial gastrointestinal juices, while strain R29 displayed the strongest bile salt tolerance. Further studies on their probiotic properties can be conducted to explore their probiotic effects as food-source probiotics.