Effects of Exposure to Low Levels of Water-Borne 17b-Estradiol on Nest Holding Ability and Sperm Quality in Fathead Minnows
Bibliographic record
Abstract
This study assessed the effects of exposure to low levels of estradiol (E2), as they have been found in some treated sewage effluents, on nest holding ability and sperm quality, two measures likely related to reproductive success in fathead minnows (Pimephales promelas), a species with paternal nest care.Male fathead minnows were exposed for 21 days to either 50 ng/L (E2) in 25 l/L ethanol, an E2 concentration found in the effluent of some British and Canadian sewage treatment plants (STP), or to a 25 l/L ethanol control (aqueous flow-through exposure).After exposure, groups of six males from one treatment were placed into an observation aquarium with females and a limited number of spawning sites and allowed to spawn for four days.Plasma vitellogenin (VTG) concentrations, the ability to acquire and defend a nest site, and sperm quality were compared between E2 exposed and control males.E2 exposure resulted in a significant increase in VTG concentrations in E2 exposed males, but did not affect nest holding ability or sperm quality.These preliminary results indicate little effect of 21-day exposure to levels of E2 that match the highest reported E2 loads in STP effluent, and parallel our findings from a previous study using goldfish.However, caution is warranted in extrapolating these results to populations of wild fish, as other factors such as the overall estrogenic potency of effluent, the duration and timing of exposure to estrogenic compounds, and the competition between fish for spawning opportunities need to be estimated.
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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 | 0.000 |
| 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) | 0.000 | 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".