Heat stress (HS) during gestation has been associated with negative outcomes, such as preterm birth or postnatal metabolic syndromes. The intestinal microbiota is a unique ecosystem playing an essential role in mediating the metabolism and health of mammals. Here we hypothesize late gestational HS alters maternal microbial transmission and structures offspring’s intestinal microbiota and serum metabolic profiles. Our results show maternal HS alters bacterial β-diversity and composition in sows and their piglets. In the maternal intestine, genera Ruminococcaceae UCG-005, [Eubacterium] coprostanoligenes group and Halomonas are higher by HS (q < 0.05), whereas the populations of Streptococcus, Bacteroidales RF16 group_norank and Roseburia are decreased (q < 0.05). In the maternal vagina, HS mainly elevates the proportions of phylum Bacteroidetes and Fusobacteria (q < 0.05), whereas reduces the population of Clostridiales Family XI (q < 0.05). In the neonatal intestine, maternal HS promotes the population of Proteobacteria but reduces the relative abundance of Firmicutes (q < 0.05). Moreover, the core Operational taxonomic units (OTU) analysis indicates the proportions of Clostridium sensu stricto 1, Romboutsia and Turicibacter are decreased by maternal HS in the intestinal and vaginal co-transmission, whereas that of phylum Proteobacteria and Epsilonbacteraeota, such as Escherichia-Shigella, Klebsiella, Acinetobacter, and Comamonas are increased in both the intestinal and vaginal co-transmission and the vagina. Additionally, Aeromonas is the only genus that is transmitted from environmental sources. Lastly, we evaluate the importance of neonatal differential OTU for the differential serum metabolites. The results indicate Acinetobacter significantly contributes to the differences in the adrenocorticotropic hormone (ACTH) and glucose levels due to HS (P < 0.05). Further, Stenotrophomonas is the most important variable for Cholesterol, low-density lipoprotein (LDL), diamine oxidase (DAO), blood urea nitrogen (BUN) and 5-hydroxytryptamine (5-HT) (P < 0.10). Overall, our data provides evidence for the maternal HS in establishing the neonatal microbiota via affecting maternal transmission, which in turn affects the maintenance of metabolic health.

Potential nuclear accidents propel serious environmental pollution, and the resultant radionuclide release devastates severely the environment severely and threatens aquatic organism survival. Likewise, ongoing climate change coupled with the gradual increase in global surface temperatures can also adversely impact the aquatic ecosystems. In the present study, we preconditioned zebrafish (Danio rerio) at three different temperatures (18 °C, 26 °C and 34 °C) to investigate the effects of a temperature profile on their radiosensitivity (exposure to 20 Gy of gamma rays) to identify the potential biochemical mechanism responsible for influencing radiosensitivity. We found that preconditioning of zebrafish at different temperatures moulded specific gut microbiota configurations and impacted hepatic glycometabolism and sensitivity to subsequent radiation. Following antibiotic treatment to reduce gut bacteria, these observed differences in the expression of hepatic glycometabolism-related genes and radiation-induced intestinal toxicity were minimal, supporting the hypothesis that the gut bacteria reshaped by different ambient temperatures might be the key modulators of hepatic functions and radiosensitivity in zebrafish. Together, our findings provide novel insights into the connection of radiation injuries with temperature alterations in fish, and suggest that maintaining the stability of gram-positive bacteria may be efficacious to protect aquatic organisms against short or long-term radioactive contamination in the context of global climate change.