The gut microbiota of healthy and Flavobacterium psychrophilum-infected rainbow trout fry and the effect of antibiotics and phage therapies

In the aquaculture sector, there is an increased interest in developing environmentally friendly alternatives to antibiotics in the treatment and prevention of bacterial infections. In this study, we focused on the freshwater pathogen Flavobacterium psychrophilum and investigated the effects of antibiotics (florfenicol) and phage therapies on the gut microbiota of healthy and infected rainbow trout fry (1-2 g). Florfenicol-coated feed was administered for 10 days starting two days after the infection procedure. A two component mix of phage targeting F. psychrophilum (FpV4 and FPSV-D22) was continuously delivered by feed with a prophylactic period of 12 days. Samples of the distal intestine were collected over time (day -1 and 1, 8 and 33 days post infection) and analyzed by community analysis targeting the 16S rRNA gene (V3-V4 region).

在水产养殖领域，开发用于治疗和预防细菌性感染的环保型抗生素替代方案的关注度日益提升。本研究以淡水致病菌嗜冷黄杆菌（Flavobacterium psychrophilum）为研究对象，探究了抗生素（氟苯尼考，florfenicol）与噬菌体疗法对健康及感染状态下体重1~2g的虹鳟鱼苗肠道菌群的影响。于感染操作完成后2天开始，给受试鱼投喂包被有氟苯尼考的饲料，持续给药10天。针对嗜冷黄杆菌的双组分噬菌体混合物（FpV4与FPSV-D22）通过饲料持续递送，预防给药周期为12天。在不同时间点（感染前1天、感染后第1、8及33天）采集远端肠道样本，通过靶向16S rRNA基因V3~V4区的菌群群落分析完成相关检测。