Integrated transcriptomic and metabolomic analyses provide new insights into the response of black rockfish (Sebastes schlegelii) larvae to temperature fluctuations.
Black rockfish larvae show significantly reduced survival rates under constant high temperatures compared to fluctuating temperatures, indicating different physiological stress responses.
Where it sits
this study against the rest of the matrixyl corpusSummary and findings
This study examined the hepatic responses of black rockfish (Sebastes schlegelii) larvae to different temperature regimes over 8 days. The larvae were subjected to constant temperatures and intermittent fluctuations, with survival rates measured. Notably, the survival rate in the high-temperature group was significantly lower than in the other groups.
Abstract
Sebastes schlegelii usually encounter elevated and fluctuating water temperatures near its upper thermal limit in summer, yet the hepatic responses of larvae to repeated temperature fluctuation regimes remain unclear. To address this question, S. schlegelii larvae were exposed for 8 days to four thermal regimes: constant 18 °C (CT), constant 28 °C (HT), intermittent cooling from 18 to 8 °C followed by recovery to 18 °C (FL), and intermittent warming from 18 to 28 °C followed by recovery to 18 °C (FH). Survival rate was evaluated, and integrated liver transcriptomic and metabolomic analyses were performed. Final survival rates were 96.67% in the CT group, 97.78% in the FL group, and 77.78% in the FH group. Survival rate in the HT group (38.89%) was significantly lower than that in the other three groups (P < 0.05). HTvsCT, FLvsCT, FHvsCT, and FHvsHT comparisons identified 2598, 1207, 622, and 2404 differentially expressed genes and 627, 606, 690, and 610 differential metabolites, respectively. KEGG enrichment analyses of DEGs and SDMs in HTvsCT highlighted HSP-mediated proteostasis, endoplasmic-reticulum protein processing, branched-chain and sulfur amino acid metabolism, glutathione metabolism, and central carbon metabolism, with upregulated hsp90aa1, bckdha, gclc, and pfkp and reduced levels of branched-chain amino acids and methionine. Compared with HT, FH showed attenuated disturbances in proteostasis, amino acid and redox regulation, and central carbon metabolism, together with recovery-associated glycerophospholipid turnover. FL primarily induced polyunsaturated fatty acid (PUFA)-related membrane lipid remodeling. These findings indicate that hepatic responses differed between continuous high-temperature exposure and temperature fluctuations and between fluctuation regimes.
Background
The study investigates the hepatic responses of black rockfish larvae to temperature fluctuations, a critical environmental stressor. Prior research has indicated that temperature extremes can affect fish physiology, but the specific responses of larvae to fluctuating temperatures remain poorly understood. This study aims to fill that gap by analyzing both transcriptomic and metabolomic changes in response to different thermal regimes.
Methods
The study employed an experimental design exposing S. schlegelii larvae to four thermal regimes for 8 days: constant 18 °C (CT), constant 28 °C (HT), intermittent cooling (FL), and intermittent warming (FH). The primary outcome measure was survival rate, while secondary measures included transcriptomic and metabolomic analyses.
Results
The primary endpoint indicated that the survival rate in the HT group was 38.89%, significantly lower than in the CT, FL, and FH groups (P < 0.05). The study identified a total of 2598 differentially expressed genes in the HT vs CT comparison, with corresponding metabolomic changes.
Interpretation
The findings suggest that continuous high-temperature exposure leads to significant physiological stress compared to temperature fluctuations. The effect sizes observed, while statistically significant, may not translate to clinically meaningful outcomes in broader ecological contexts. Limitations include the lack of long-term follow-up and potential confounding factors related to the experimental setup.
Key findings
- Final survival rates were 96.67% in the CT group, 97.78% in the FL group, and 77.78% in the FH group.
- Survival rate in the HT group was 38.89%, significantly lower than that in the other three groups (P < 0.05).
- HTvsCT identified 2598 differentially expressed genes and 627 differential metabolites.
- FLvsCT identified 1207 differentially expressed genes and 606 differential metabolites.
- FHvsCT identified 622 differentially expressed genes and 690 differential metabolites.
- FHvsHT identified 2404 differentially expressed genes and 610 differential metabolites.
Limitations
- Not reported in abstract.