This study was aimed to assess the effect of a novel postbiotic on bacterial community composition and structure within the intestinal ecosystem of rainbow trout (Oncorhynchus mykiss), as well as evaluate its capacity to protect rainbow trout from Lactococcus garvieae infection. After 30 days of dietary postbiotic supplementation, high-throughput 16S rRNA gene sequencing revealed that bacterial community composition, diversity and richness were significantly higher in treated fish than in control fish. The proportion of sequences affiliated to the phylum Tenericutes, and to a lesser extent, the phyla Spirochaetes and Bacteroidetes was increased in fish fed a postbiotic-enriched diet compared to control fish, whereas the abundance of Fusobacteria was higher in control fish. Moreover, the treated fish showed significantly (p < 0.05) improved protection against L. garvieae compared to control fish. These findings suggest that dietary postbiotic supplementation may represent an environmentally friendly strategy for preventing and controlling diseases in aquaculture.

中文翻译：

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一种含有乳酸菌的新型后生素对虹鳟鱼肠道菌群和抗病性的影响（Oncorhynchus mykiss）

本研究旨在评估一种新型后生素对虹鳟 (Oncorhynchus mykiss) 肠道生态系统内细菌群落组成和结构的影响，并评估其保护虹鳟免受加维乳球菌感染的能力。在膳食补充益生菌 30 天后，高通量 16S rRNA 基因测序显示，处理鱼的细菌群落组成、多样性和丰富度显着高于对照鱼。与对照鱼相比，与对照鱼相比，在富含益生菌的饮食喂养的鱼中，隶属于 Tenericutes 门的序列比例增加，螺旋菌门和拟杆菌门在较小程度上增加，而梭杆菌在对照鱼中的丰度更高。此外，经过处理的鱼表现出显着性（p < 0. 05) 与对照鱼相比，提高了对 L. garvieae 的保护。这些发现表明，膳食后生素补充剂可能代表了一种预防和控制水产养殖疾病的环保策略。