Integration of photoperiod and time-restricted feeding on the circadian gene rhythms in juvenile salmon
Bibliographic record
Abstract
The circadian clock has evolved to synchronize animal behaviour and physiology with the external environment. Present in almost all cells, the clock is made up of a transcription-translation feedback loop that is responsive to cues such as light/dark cycles (photoperiod) and the time of feeding. Chinook salmon (Oncorhynchus tshawytscha) is a fish species whose clock is thought to be adapted in natural populations according to their latitude, where photoperiod variation can be extreme in northern spring/summer conditions. Here, we probed for the expression of circadian clock genes in four tissues of juvenile Chinook salmon under different environmental conditions. We find that the circadian clock is optimal when photoperiod is coupled with regular feeding during daylight hours. We further tested the effects of constant light and time-restricted feeding, environmental factors that are known to affect daily gene expression rhythms, on the expression of clock genes, appetite-regulating hormones, and metabolic regulators in the intestine of juvenile Chinook. We find that overall constant light is chrono-disruptive irrespective of the timing of food. The resulting disruption in gene expression produces aberrant rhythms, and affects glucose homeostasis, despite an increase in growth. Our data suggests photoperiod and time-restricted feeding could be optimized in Chinook aquaculture and raise the question of whether and how photoperiod changes are compensated in northern-adapted populations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".