Abstract：
With the emergence of diseases, the U.S. catfish industry is under challenge. Current trends prefer autochthonous bacteria as potential probiotic candidates owing to their adaptability and capacity to effectively colonize the host\'s intestine, which can enhance production performance and bolster disease resistance. The objective of this study was to isolate an autochthonous bacterium as probiotic for hybrid catfish. Initially, an analysis of the intestinal microbiota of hybrid catfish reared in earthen ponds was conducted for subsequent probiotic development. Twenty lactic acid bacteria were isolated from the digesta of overperforming catfish, and most of the candidates demonstrated probiotic traits, including proteolytic and lipolytic abilities; antagonistic inhibition of catfish enteric bacterial pathogens, negative haemolytic activity and antibiotic susceptibility. Subsequent to this screening process, an isolate of Lactococcus lactis (MA5) was deemed the most promising probiotic candidate. In silico analyses were conducted, and several potential probiotic functions were predicted, including essential amino acids and vitamin synthesis. Moreover, genes for three bacteriocins, lactococcin A, enterolysin A and sactipeptide BmbF, were identified. Lastly, various protectant media for lyophilization of MA5 were assessed. These findings suggest that Lactococcus lactis MA5 can be an autochthonous probiotic from hybrid catfish, holding promise to be further tested in feeding trials.
摘要：
随着疾病的出现,美国鲶鱼产业面临挑战。由于其适应性和有效定殖宿主肠道的能力，目前的趋势更喜欢将本地细菌作为潜在的益生菌候选物。这可以提高生产性能并增强抗病性。这项研究的目的是分离出一种本地细菌作为杂种cat鱼的益生菌。最初，对在土塘饲养的杂交鲶鱼的肠道微生物群进行了分析，以进行随后的益生菌开发。从表现优异的cat鱼的消化物中分离出20种乳酸菌，大多数候选人表现出益生菌特性，包括蛋白水解和脂肪分解能力；拮抗抑制鲶鱼肠道细菌病原体，溶血活性阴性和抗生素敏感性。在这个筛选过程之后，乳酸乳球菌（MA5）的分离株被认为是最有希望的益生菌候选物。进行了计算机模拟分析，并预测了几种潜在的益生菌功能，包括必需氨基酸和维生素合成。此外，三种细菌素的基因，乳球菌A,肠溶素A和肌动肽BmbF，已确定。最后,评估了用于冻干MA5的各种保护剂介质。这些发现表明，乳酸乳球菌MA5可能是来自杂交cat鱼的自生益生菌，持有在喂养试验中进一步测试的承诺。
