Egg yolk-free cryopreservation of bull semen
Bibliographic record
Abstract
Egg yolk is a common ingredient of mammalian semen extender to protect sperm against initial cold shock. However, egg yolk has biosecurity risks. Our main objectives were to cryopreserve bull semen without egg yolk using exogenous cholesterol and to study the protective role of glycerol in egg yolk-free semen extender. Other objectives were to compare protein profiles and in vitro fertilization potential of bull sperm frozen with and without egg yolk. In first experiment, semen was either diluted in conventional tris-egg yolk glycerol (TEYG control) extender or first treated with cholesterol-cyclodextrin complex (CC, 2 mg/ml semen) followed by dilution in egg yolk-free tris-glycerol (TG) extender (collectively called as "CC+TG") at 22°C or 4°C, and frozen. Post-thaw sperm motion characteristics were similar between CC+TG and TEYG control extenders, and temperature of glycerol addition. In second experiment, semen was frozen in CC+TG extender varying in glycerol concentration (7 to 0%; v/v). Post-thaw sperm quality decreased with the decline in glycerol concentration in TG extender, even higher concentration of CC complex (3 or 4 mg/ml semen) could not protect sperm in the absence of glycerol in TG extender. In third experiment, SDS electrophoresis of proteins from fresh sperm and sperm frozen in CC+TG, and TEYG control extenders was conducted. Protein profiles in fresh sperm and CC+TG frozen sperm were almost similar. Egg yolk proteins bound tightly with sperm plasma membrane. In fourth experiment, in vitro fertilization potentials of sperm frozen in TEYG control and CC+TG extenders were tested. Cleavage and blastocyst rates of semen frozen in CC+TG and TEYG control extenders were similar. In conclusion, cholesterol-cyclodextrin replaced egg yolk from the semen extender; glycerol remained essential for egg yolk-free sperm cryopreservation; and CC+TG extender did not modify sperm plasma membrane CC+TG whereas egg yolk extender changed the plasma membrane composition of bull sperm.
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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) | 0.001 | 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 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".