Antibiotics are widely used in aquaculture to treat the bacterial diseases. However, the improper use of antibiotics could lead to environmental pollution and development of resistance. As a safe and eco-friendly alternative, antimicrobial peptides (AMPs) are commonly explored as therapeutic agents. In this study, a mutant strain of Tetraselmis subcordiformis containing AMP NZ2114 was developed and used as an oral drug delivery system to reduce the use of antibiotics in turbot (Scophthalmus maximus) aquaculture. The gut, kidney, and liver immune-related genes and their effects on gut digestion and bacterial communities in turbot fed with NZ2114 were evaluated in an 11-day feeding experiment. The results showed that compared with the group fed with wild-type T. subcordiformis, the group fed with T. subcordiformis transformants containing NZ2114 was revealed with decreased levels of both pro-inflammatory factors (TNF-α and IL-1β), inhibitory effect on Staphylococcus aureus, Vibrio parahaemolyticus, and Vibrio splendidus demonstrated by the in vitro simulation experiments, and increased richness and diversity of the gut microbiota of turbot. In conclusion, our study provided a novel, beneficial, and low-cost method for controlling bacteria in turbot culture through the oral drug delivery systems.

抗生素在水产养殖中广泛用于治疗细菌性疾病。然而，抗生素使用不当可能会导致环境污染和耐药性的产生。作为一种安全且环保的替代品，抗菌肽（AMP）通常被探索作为治疗剂。在本研究中，开发了一种含有 AMP NZ2114的Tetraselmis subcordiformis突变菌株，并将其用作口服药物递送系统，以减少大菱鲆（ Scophamus maximus）水产养殖中抗生素的使用。在为期 11 天的喂养实验中评估了饲喂 NZ2114 的大菱鲆的肠道、肾脏和肝脏免疫相关基因及其对肠道消化和细菌群落的影响。结果显示，与饲喂野生型亚心形毛虫组相比，饲喂含有NZ2114的亚心形毛虫转化子组，促炎因子（TNF-α和IL-1β）水平降低，抑制作用明显。体外模拟实验证明，对金黄色葡萄球菌、副溶血性弧菌和灿烂弧菌有效，增加了大菱鲆肠道菌群的丰富度和多样性。总之，我们的研究提供了一种通过口服给药系统控制大菱鲆培养物中细菌的新颖、有益且低成本的方法。