Duress without stress: Cryptobia infection results in HPI axis dysfunction in rainbow trout
Bibliographic record
Abstract
Despite clear physiological duress, rainbow trout (Oncorhynchus mykiss) infected with the pathogenic haemoflagellate Cryptobia salmositica do not appear to mount a cortisol stress response. Therefore, we hypothesized that the infection suppresses the stress response by inhibiting the key effectors of the hypothalamic-pituitary-interrenal (HPI) axis. To test this, we characterized the basal activity of the HPI axis and the cortisol response to air exposure in saline- and parasite-injected fish. All fish were sampled at 4 and 6 weeks post-injection (wpi). While both the treatment groups had resting plasma cortisol levels, the parasite-infected fish had lower levels of plasma ACTH than the control fish. Relative to the control fish, the infected fish had higher mRNA levels of brain pre-optic area corticotrophin-releasing factor (CRF) and pituitary CRF receptor type 1, no change in pituitary POMC-A1, -A2 and -B gene expression, higher and lower head kidney melanocortin 2 receptor mRNA levels at 4 and 6 wpi respectively and reduced gene expression of key proteins regulating interrenal steroidogenesis: StAR, cytochrome P450scc and 11β-hydroxylase. The parasite-infected fish also had a reduced plasma cortisol response to a 60-s air exposure stressor. Superfusion of the head kidney tissues of the parasite-infected fish led to significantly lower ACTH-stimulated cortisol release rates than that observed in the control fish. These novel findings show that infection of rainbow trout with C. salmositica results in complex changes in the transcriptional activity of both central and peripheral regulators of the HPI axis and in a reduction in the interrenal capacity to synthesize cortisol.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".