Use of a Vascular Access Port for the Measurement of Pulsatile Luteinizing Hormone in Old Broiler Breeders
Bibliographic record
Abstract
Techniques used to measure circulating hormone concentrations in avian species over extended periods routinely involve cannulation or multiple venipunctures under physical restraint, resulting in sepsis and stress. We adapted a method for serial blood sampling in chickens using a vascular access port (VAP) surgically implanted under the skin of the neck and connected to a catheter inserted in the right jugular vein. The system was used to measure circulating luteinizing hormone (LH) profiles in six, 21-mo-old broiler breeders at the end of their laying period. The VAP were implanted under general anesthesia, and, after a period of recovery, serial blood samples (every 10 min for 6 h) were collected using an extension line connected to a push-pull system. Birds were unrestrained and had free access to food and water. Red blood cells were recovered by centrifugation, reconstituted in saline solution, and returned to the donor bird through the VAP once every 90 min. Luteinizing hormone levels were subsequently measured in plasma by radioimmunoassay. With the exception of 1 hen that developed valvular endocarditis, no sign of disease or infection was observed throughout the study, and the VAP remained functional in all birds for at least 3 mo. Thus, our results suggest that VAP are a safe, reliable, and less stressful technique for serial blood sampling and long-term studies. Radioimmunoassay results revealed that in old birds, circulating LH levels followed a pulsatile pattern, with pulse amplitudes ranging from 1.35 to 2.02 ng/mL and pulse frequencies ranging from 5 to 6 peaks per 6 h. Although not significant, amplitude of LH pulses in out-of-lay hens appeared to be lower than in laying hens.
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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 | 0.001 | 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".