Dhanasiri Anusha K S, Li Yanxian, Krogdahl Åshild, Forberg Torunn, Kortner Trond M
Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway.
Biomar, Trondheim, Norway.
Anim Microbiome. 2024 Dec 20;6(1):71. doi: 10.1186/s42523-024-00360-1.
Antibiotic use has undesirable side-effects on the host, including perturbations of gut microbiota, immunity, and health. Mammalian studies have demonstrated that concomitant/post antibiotic use of pro-, pre-, and synbiotics could re-establish gut microbiota and prevent detrimental host effects. However, studies evaluating similar effects in fish are scanty. This study evaluated the effects of dietary supplementation with a synbiotic mixture on the post-smolt Atlantic salmon gut microbiota, growth performance, and health during antibiotic treatment and subsequent recovery. Fish in five tanks each were fed either a commercial control diet or a synbiotic diet containing Pediococcus acidilactici and fructo-oligosaccharides, for 6 weeks (S1). Then, fish in three tanks per treatment were fed with medicated diets, containing 3500 ppm florfenicol coated onto the control or synbiotic diets, for 2 weeks (S2) and refed with the respective nonmedicated diets for another 3 (S3) and 5 (S4) weeks of recovery period. The fish not subjected to medication were fed the control or synbiotic diets throughout the experimental period. Samples were collected at S1-S4 from both the nonmedicated and medicated fish.
Florfenicol decreased the feed intake in control group. It reduced the growth rate in both control and synbiotic groups with lesser reduction in synbiotic group. Florfenicol did not significantly affect observed taxa and Shannon indexes. Bacterial composition before and after medication clustered distinctly in control and clustered together in synbiotic groups. Lactobacillus dominated in control while Lactobacillus and Pediococcus dominated in synbiotic group during medication and recovery. Florfenicol did not significantly influence the immune or stress response marker gene expressions, though the expression patterns differed between diet groups. Florfenicol did not cause inflammation in the distal intestine or change hepatosomatic index.
This study highlighted the negative impact of a two-week florfenicol treatment on feed intake and growth performance in Atlantic salmon, with moderate effects on gut microbiota and gene expression. Concomitant use of a synbiotic diet helped to maintain the gut microbial composition and influenced the performance positively and immune gene expressions differently during medication. This study indicates the importance of nutritional interventions through synbiotic supplementation as a possible strategy for managing Atlantic salmon during antibiotic treatment.
抗生素的使用会对宿主产生不良副作用，包括扰乱肠道微生物群、免疫力和健康状况。哺乳动物研究表明，在使用抗生素的同时/之后使用益生元、益生菌和合生元可以重建肠道微生物群，并预防对宿主的有害影响。然而，评估鱼类中类似效果的研究却很少。本研究评估了在抗生素治疗及随后的恢复过程中，日粮添加合生元混合物对大西洋鲑鱼幼鲑肠道微生物群、生长性能和健康状况的影响。将每个处理组的鱼分别饲养在五个水箱中，其中一组投喂商业对照饲料，另一组投喂含有嗜酸乳杆菌和低聚果糖的合生元饲料，持续6周（阶段1）。然后，每个处理组的三个水箱中的鱼投喂含3500 ppm氟苯尼考的药饵，药饵分别添加在对照饲料或合生元饲料上，持续2周（阶段2），之后再分别投喂各自的非药饵3周（阶段3）和5周（阶段4）进行恢复期饲养。未接受药物处理的鱼在整个实验期间投喂对照饲料或合生元饲料。在阶段1至阶段4期间，分别从未经药物处理和经药物处理的鱼中采集样本。
氟苯尼考降低了对照组的采食量。它降低了对照组和合生元组的生长速率，其中合生元组的降低幅度较小。氟苯尼考对观察到的分类群和香农指数没有显著影响。药物处理前后的细菌组成在对照组中明显聚类，而在合生元组中聚类在一起。在药物处理和恢复期间，对照组中以乳杆菌为主，而合生元组中乳杆菌和片球菌为主。氟苯尼考对免疫或应激反应标记基因的表达没有显著影响，尽管不同日粮组之间的表达模式有所不同。氟苯尼考没有引起远端肠道炎症或改变肝体指数。
本研究强调了为期两周的氟苯尼考处理对大西洋鲑鱼采食量和生长性能的负面影响，对肠道微生物群和基因表达有中等程度的影响。同时使用合生元日粮有助于维持肠道微生物组成，并在药物处理期间对生长性能产生积极影响，对免疫基因表达产生不同影响。本研究表明，通过添加合生元进行营养干预作为在抗生素治疗期间管理大西洋鲑鱼的一种可能策略具有重要意义。
