Ectothermic fish exposure to hypothermal stress requires adjusting their metabolic molecular machinery, which was investigated using Indian medaka (Oryzias dancena; 10 weeks old, 2.5 ± 0.5 cm) cultured in fresh water (FW) and seawater (SW; 35‰) at room temperature (28 ± 1 °C). The fish were fed twice a day, once in the morning and once in the evening, and the photoperiod was 12 h:12 h light: dark. In this study, we applied two hypothermal treatments to reveal the mechanisms of energy metabolism via pgc-1α regulation in the gills of Indian medaka; cold-stress (18 °C) and cold-tolerance (extreme cold; 15 °C). The branchial ATP content was significantly higher in the cold-stress group, but not in the cold-tolerance group. In FW- and SW-acclimated medaka, the expression of genes related to mitochondrial energy metabolism, including pgc-1α, prc, Nrf2, tfam, and nd5, was analyzed to illustrate differential responses of mitochondrial energy metabolism to cold-stress and cold-tolerance environments. When exposed to cold-stress, the relative mRNA expression of pgc-1α, prc, and Nrf2 increased from 2 h, whereas that of tfam and nd5 increased significantly from 168 h. When exposed to a cold-tolerant environment, prc was significantly upregulated at 2 h post-cooling in the FW and SW groups, and pgc-1α was significantly upregulated at 2 and 12 h post-cooling in the FW group, while tfam and nd5 were downregulated in both FW and SW fish. Hierarchical clustering revealed gene interactions in the cold-stress group, which promoted diverse mitochondrial energy adaptations, causing an increase in ATP production. However, the cold-tolerant group demonstrated limitations in enhancing ATP levels through mitochondrial regulation via the PGC-1α energy metabolism pathway. These findings suggest that ectothermic fish may develop varying degrees of thermal tolerance over time in response to climate change. This study provides insights into the complex ways in which fish adjust their metabolism when exposed to cold stress, contributing to our knowledge of how they adapt.

Cold snaps during the winter present a critical challenge for Asian seabass (Lates calcarifer) in Taiwan, as sudden temperature drops significantly affect their growth and survival. This study explores the effects of dietary grape extract (GE) from Vitis vinifera on the growth performance, oxidative stress regulation, and thermal tolerance of this commercially valuable fish. Over a 60-day feeding trial, four dietary groups were tested: a control diet without GE and three diets supplemented with GE at 2% (GE20), 3% (GE30), and 4% (GE40) with commercial feed. The results demonstrated that GE supplementation positively influenced growth, with the GE20 group achieving the best weight gain and feed conversion ratio among all groups. The upregulation of the growth-related gene igf-1 in the liver of the GE20 group further supported its superior growth performance. Additionally, GE-fed groups showed increased expression of antioxidant-related genes sod1 and sod2 in the liver, while gpx1 exhibited a significant increase only in the GE20 group, indicating enhanced antioxidant defenses. Cat gene expression remained unchanged, and higher GE doses reduced the expression of gpx1, cat, and igf-1. Furthermore, GE supplementation improved cold tolerance in all treated groups compared to the control. These findings suggest that dietary GE at 20 g/kg is particularly effective in enhancing growth performance and cold tolerance in Asian seabass, offering a promising strategy for boosting fish health and adaptability in aquaculture.

Rapid climatic fluctuations increasingly expose fish to concurrent temperature and salinity stresses, threatening physiological stability and aquaculture productivity. Euryhaline teleosts, which tolerate wide osmotic ranges, serve as ideal models for exploring adaptive mechanisms to such compound environmental challenges. This chapter integrates recent multi-omics findings – encompassing transcriptomic, proteomic, metabolomic, and lipidomic data – to elucidate the molecular and cellular bases of cold stress adaptation in relation to salinity. Cold exposure suppresses aerobic metabolism, disrupts ion transport, and induces oxidative stress through mitochondrial dysfunction. Euryhaline fishes mitigate these effects through coordinated activation of mitochondrial biogenesis, antioxidant defenses, and membrane remodeling, regulated by PGC-1α, NRF2, TFAM, and AMPK–SIRT1 signaling. Salinity modulates the energetic cost of osmoregulation, shaping mitochondrial plasticity and ionic resilience; seawater acclimation consistently enhances adenosine triphosphate (ATP) production, stabilizes redox balance, and reduces apoptotic injury. Integrated omics analyses reveal that cross-talk between ionoregulatory pathways, energy metabolism, and redox regulation underpins osmo-thermal tolerance. Application of these mechanistic insights – through cold salinity acclimation regimes, nutritional fortification, and marker-assisted selection targeting genes linked to mitochondrial efficiency and ion transport – offers promising strategies to improve cold resilience in aquaculture species. Future incorporation of epigenomic and small-RNA profiling, coupled with functional validation using CRISPR-based editing, will further clarify causal regulatory networks and support predictive modeling of fish adaptation under compound environmental stress.

Background: Polygonum cuspidatum (Hu Zhang) is a polyphenol-rich botanical in which resveratrol occurs at low levels mainly as polydatin. In this study, we generated a microbially converted P. cuspidatum extract (CPE) with markedly enriched resveratrol content from the unconverted P. cuspidatum extract (PE), and evaluated its anticancer efficacy and safety in comparison with those of the unconverted extract. Methods: High-performance liquid chromatography (HPLC), A549 cell-based assays, an A549 xenograft model, and a 28-day repeated-dose rat study were performed. Results: HPLC showed near-complete depletion of polydatin, marked enrichment of resveratrol, and a modest reduction in emodin. CPE more effectively inhibited A549 cell proliferation and migration than PE, suppressed NLRP3 inflammasome and nuclear factor kappa B (NFκB) signaling, and promoted reactive oxygen species (ROS) accumulation and mitochondrial apoptosis. Oral CPE also significantly reduced tumor growth in an A549 xenograft model. In a 28-day repeated-dose rat study, no treatment-related abnormalities were observed in blood biochemistry or histopathology. Conclusions: These findings support CPE as a promising functional food ingredient.

Geometric morphometrics and mitochondrial cytochrome oxidase I (COI) DNA barcoding are crucial for identifying closely related cryptic carangid species. We integrated both taxonomic methods for promising identification within selected carangid groups, trevallies (Turrum coeruleopinnatum, Platycaranx malabaricus, and Atropus hedlandensis) and scads (Selar crumenophthalmus, Selar boops, and Atule mate). Despite a plethora of carangid barcode data, the knowledge bridge on carangid evolutionary footprints provides limited information on their origin, evolution, and distribution. Procrustes-defined data derived from shape differences between species and between morphs within species were analyzed by principal component analysis (PCA) and canonical variate analysis (CVA) (P < 0.0001), and were independent of intraspecific variation. Geometric morphometric clustering was evaluated using mtDNA COI barcoding, and each morph/species cluster was found to be compatible with the corresponding species. Average Kimura 2- Parameter (K2P) divergences were obtained in accordance with taxonomic hierarchy and were consistent with the 2% species delimitation: conspecific, congeneric, confamilial divergences were 0.28%, 4.50%, and 11.90% respectively and intraspecific and interspecific divergences were in the ranges (0.00-0.60)% and (2.10-18.70)% respectively. The greatest divergence was observed between the Indian and Indo-Australian Archipelago (IAA) individuals, whereas the lowest divergence was observed between the common ancestral cluster and IAA individuals. However, both consolidated taxonomic approaches provided a clear resolution of the selected carangid species over cryptic speciation. The origin of the carangid ancestor and its centered distribution in the IAA region are well described by regional characteristic divergences and are further explained by the center of origin and overlap hypotheses.