GreenCoLab-Associação Oceano Verde, University of Algarve, Campus of Gambelas, Bldg7, Faro, Portugal.
MARE-Marine and Environmental Sciences Centre, Polytechnic of Leiria, Edifício CETEMARES, Av. Porto de Pesca, 2520-620, Peniche, Portugal.
Sci Rep. 2022 Sep 1;12(1):14836. doi: 10.1038/s41598-022-17891-9.
Seaweeds are an important source of nutrients and bioactive compounds and have a high potential as health boosters in aquaculture. This study evaluated the effect of dietary inclusion of Gracilaria gracilis biomass or its extract on the European seabass (Dicentrarchus labrax) gut microbial community. Juvenile fish were fed a commercial-like diet with 2.5% or 5% seaweed biomass or 0.35% seaweed extract for 47 days. The gut microbiome was assessed by 16S rRNA amplicon sequencing, and its diversity was not altered by the seaweed supplementation. However, a reduction in Proteobacteria abundance was observed. Random forest analysis highlighted the genera Photobacterium, Staphylococcus, Acinetobacter, Micrococcus and Sphingomonas, and their abundances were reduced when fish were fed diets with algae. SparCC correlation network analysis suggested several mutualistic and other antagonistic relationships that could be related to the predicted altered functions. These pathways were mainly related to the metabolism and biosynthesis of protective compounds such as ectoine and were upregulated in fish fed diets supplemented with algae. This study shows the beneficial potential of Gracilaria as a functional ingredient through the modulation of the complex microbial network towards fish health improvement.
海藻是营养物质和生物活性化合物的重要来源，具有作为水产养殖健康促进剂的巨大潜力。本研究评估了在饲料中添加裙带菜（Gracilaria gracilis）生物质或其提取物对欧洲海鲈（Dicentrarchus labrax）肠道微生物群落的影响。幼鱼食用含 2.5%或 5%海藻生物质或 0.35%海藻提取物的商业饲料 47 天。通过 16S rRNA 扩增子测序评估肠道微生物组，海藻补充并未改变其多样性。然而，观察到变形菌门丰度减少。随机森林分析突出了 Photobacterium、Staphylococcus、Acinetobacter、Micrococcus 和 Sphingomonas 等属，当鱼食用含有藻类的饲料时，它们的丰度降低。SparCC 相关网络分析表明了几种互利和其他拮抗关系，这些关系可能与预测的功能改变有关。这些途径主要与保护化合物如章鱼胺的代谢和生物合成有关，在食用藻类补充饲料的鱼类中上调。本研究表明，通过调节复杂的微生物网络，裙带菜作为一种功能性成分具有潜在的益处，可改善鱼类健康。
