2026-06-11 東京大学,長崎大学
図1：トラフグ稚魚へのTTX投与実験のイメージ
人工的に孵化、飼育した無毒のトラフグ稚魚を4段階の塩分条件に順馴した後、フグ毒TTXを混ぜた餌を与えながら10日間飼育し、同時に毒を混ぜていない餌を与えた稚魚と腸内フローラを比較した。
＜関連情報＞
- https://www.aori.u-tokyo.ac.jp/research/news/2026/20260611.html
- https://link.springer.com/article/10.1186/s42523-026-00572-7
テトロドトキシン（TTX）は、塩分濃度勾配全体にわたって、幼魚のトラフグ（Takifugu rubripes ）の腸内マイクロバイオームの機能的可能性を再構築する Tetrodotoxin (TTX) reshapes the functional potential of the gut microbiome in juvenile tiger pufferfish (Takifugu rubripes) across salinity gradients
Mai A. Wassel,Yoko Makabe-Kobayashi,Md Mehedi Iqbal,Can Huang,Masafumi Amano,Aika Shimizu,Mary Anne E. Mandario,Tomohiro Takatani,Yoshitaka Sakakura & Koji Hamasaki
Animal Microbiome Published:11 June 2026
DOI:https://doi.org/10.1186/s42523-026-00572-7
Abstract
Background
The gut microbiota of aquatic organisms responds dynamically to environmental stressors such as salinity fluctuations. However, how microbial communities respond to combined environmental and dietary stressors, and how these interactions influence functional potential, remains incompletely understood. Here, we investigated whether dietary administration of tetrodotoxin (TTX), a neurotoxin naturally accumulated by juvenile tiger pufferfish (Takifugu rubripes), alters gut bacterial community composition and functional potential across salinity gradients.
Results
Juvenile T. rubripes were reared under four salinity conditions (34.0, 17.0, 8.5, and 2.1 ppt) and fed either a control or TTX-containing diet (1.22 MU/g). Integrated 16S rRNA gene amplicon and shotgun metagenomic analyses revealed that salinity was the primary driver of gut microbiota structure, with only 5.1% of amplicon sequence variants (ASVs) shared across salinity levels. In contrast, TTX ingestion induced salinity-dependent shifts in specific bacterial taxa rather than broad community restructuring. Core taxa, including Arcobacteraceae, Mycoplasma, Brevinema, and Vibrio, were consistently detected across treatments but exhibited pronounced changes in relative abundance and functional potential under salinity and toxin stress. Metagenomic profiling indicated that Arcobacteraceae encode genetic modules for amino acid and B vitamin biosynthesis that are absent or incomplete in the host genome, suggesting metabolic complementarity. TTX ingestion reduced the genetic representation of these biosynthetic pathways at specific salinities, particularly those associated with Arcobacteraceae. Conversely, phenylalanine biosynthesis potential enriched in TTX-fed fish, primarily associated with Vibrio spp., indicating a possible microbial functional adaptation to toxin administration. Despite these microbiome and functional shifts, TTX ingestion did not affect host growth.
Conclusions
Dietary neurotoxin administration reshaped gut microbiome functional profiles in a salinity-dependent manner, highlighting microbiome plasticity and improving our understanding of host–microbiota–environment interactions relevant to aquaculture health management.
