Adaptations to intermittent fasting in large sea caged Atlantic salmon (Salmo salar); effects on feeding, energy homeostasis, and growth
Bibliographic record
Abstract
Feeding fish in excess is a common practice in the farming of Atlantic salmon to maximise fish growth and profitability. Since feed accounts for a large percentage of a farmer's operational expenses, periodic reduction of feed utilization that still enable to maintain production performance in the long run is a possible strategy to mitigate farmers economic costs and reduce feed waste. In this study we investigated how large (>3.3 kg) sea caged Atlantic salmon adapt to feeding being restricted from daily to every third day in an intermittent fasting regime for 6 weeks, followed by a 5-week refeeding period before harvest in June. Fish in control cages were fed daily, except for three days to compare feed intake with the intermittently fasted fish at the end of their fasting period. Both groups were fed based on visual observations and assessments using monitoring cameras. Fish growth, feed intake, gastrointestinal fullness, and endocrine signalling related to energy homeostasis and appetite regulation were analyzed. Salmon fed to satiation every third day gradually increased their feed intake over the first four weeks of intermittent fasting and showed a 3-fold increase in stomach content after feeding when analyzed at 3 and 6 weeks of intermittent fasting. Growth rate in intermittently fasted fish was reduced by ∼50 % and feed conversion ratio increased by ∼130 % compared to the control group. This was accompanied by a decrease in HSI and plasma levels of Ghrl as indicators of energy imbalance and an increase in hypothalamic mRNA expression of agrp1 , a neuropeptide likely involved in glucose sensing and acting as feeding stimulant. At the end of the 6-week intermittent fasting regime, the fish had elevated levels of plasma cholesterol, glucose, and lactate, suggesting reallocation of energy sources and metabolism. The metabolic adjustments did not appear to be detrimental to the fish during the intermittent fasting regime applied in this study, as they continued to grow, albeit at lower rate than fully fed fish. Further, after returning to daily feeding regime, the intermittent fasted fish showed a tendency toward compensatory growth and differences in the endocrine signals related to appetite regulation and energy homeostasis were abolished. The present results provide novel insights into the physiological mechanisms occurring during intermittent fasting in Atlantic salmon and demonstrate a feeding regime that can be applied during periods of limited food availability, or when farmers aim to achieve strategic growth targets in commercial production. • 6 weeks of intermittent fasting reduced growth and K-factor in Atlantic salmon. • When fed, fish exhibited hyperphagia and a 3-fold increase in stomach content. • Feed restriction rearranged fish appetite and energy homeostasis endocrine signalling. • Full refeeding resulted in comparable growth, appetite, and endocrine signals to control fish.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".