Linking swimming performance, cardiac pumping ability and cardiac anatomy in rainbow trout
Bibliographic record
Abstract
We exploited the inherent individual diversity in swimming performance of rainbow trout Oncorhynchus mykiss to investigate the hypothesis that maximum cardiac performance is linked to active metabolic rate (AMR) and critical swimming speed (U crit). Six hundred juveniles (body mass approximately 150 g) were screened using a swimming challenge of 1.2 m s(-1) to identify 'poor swimmers' and 'good swimmers', i.e. the first and last 60 fish to fatigue, respectively. These 120 fish were individually tagged and then reared in common tanks for 9 months, where they grew at similar rates and achieved a similar body mass of approximately 1100 g. Critical swimming speed (U crit) was then measured individually in tunnel respirometers, with simultaneous recordings of cardiac output via a ventral aortic flow probe. The group of individuals that were screened as poor swimmers remained so, with a significantly (27%) lower U crit than good swimmers [89+/-10 cm s(-1) vs 123+/-5 cm s(-1) (mean +/-s.e.m.), respectively, N = 6], a 19% lower AMR (147+/-12 micromol min(-1) kg(-1) vs 181+/-11 micromol min(-1) kg(-1), respectively), and a 30% lower maximum in vivo cardiac output (47.3+/-4.7 ml min(-1) kg(-1) vs 68.0+/-5.2 ml min(-1) kg(-1), respectively). When cardiac performance was compared with an in situ heart preparation, hearts from poor swimmers had a significantly (26%) lower maximum cardiac output (45.9+/-1.9 ml min(-1) kg(-1) vs 56.4+/-2.3 ml min(-1) kg(-1), respectively) and a 32% lower maximum cardiac power output at a high afterload (3.96+/-0.58 mW g(-1) vs 5.79+/-1.97 mW g(-1), respectively). Cardiac morphology was visualised in vivo by Doppler echography on anaesthetised individual fish and revealed that poor swimmers had a significantly more rounded ventricle (reduced ventricle length to height ratio) compared with good swimmers, which in turn was correlated with fish condition factor. These results provide clear evidence that maximum cardiac performance is linked to AMR and U crit and indicate that a simple screening test can distinguish between rainbow trout with lower active metabolic rate, U crit, maximal cardiac pumping capacity and a more rounded ventricular morphology. These distinguishing traits may have been retained for 9 months despite a common growing environment and growth.
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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 | 0.001 |
| 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".