Season affects sperm quality, seminal extracellular vesicles, and antioxidant-related genes in Egyptian Buffalo bulls
Bibliographic record
Abstract
Global climate change threatens livestock production, especially in regions where heat stress diminishes fertility. Extracellular vesicles (EVs), key players in biological processes like intercellular communication and oxidative stress regulation, are crucial in reproductive biology. The objective was to determine seasonal impacts on semen quality, oxidative stress, and antioxidant enzyme activity in Egyptian buffalo bulls, focusing on differences in EV content between bulls having high- or low-quality sperm (HQS and LQS, respectively), based on sperm motility and morphology. Semen samples were collected by artificial vagina in summer and winter. Oxidative stress markers, such as malondialdehyde (MDA), and antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GPx]) were measured in seminal plasma. Seminal plasma EVs (SP-EVs) were isolated and characterized by size, concentration, and surface markers (CD9 and CD63). Additionally, gene expression of antioxidant and apoptotic markers was analyzed using qRT-PCR. Semen quality peaked in the winter, with HQS exhibiting superior total motility (winter total motility: 79.4 ± 0.65% vs. summer: 69.9 ± 0.65%) and morphology (winter normal morphology: 75.5 ± 0.87% vs. summer: 71.3 ± 0.87%). Furthermore, LQS semen had higher MDA concentrations (summer: 1.31 ± 1.67 nmol/ml; winter: 2.62 ± 1.21 nmol/ml), indicating greater oxidative stress, whereas HQS exhibited elevated antioxidant enzyme activity, especially in summer (SOD: 292.0 ± 3.93 U/ml; CAT: 949.7 ± 15.23 U/ml; GPx: 77.7 ± 2.15 mU/ml; TAC: 9.83 ± 4.75 mM/L). Notably, SP-EVs from LQS were larger and had increased CD9 and CD63 expression, suggesting their association with oxidative damage. Conversely, SP-EVs from HQS were smaller, had lower CD9 and CD63 expression, and had upregulated (p ≤ 0.001) antioxidant genes (SOD, NFE2L2) and downregulated (p ≤ 0.001) apoptotic markers (CASP3). Expression of DNMT1 and ATF6 mRNA were elevated (p ≤ 0.001) in HQS sperm and SP-EVs, especially in summer, indicating a seasonal effect on epigenetic regulation and stress response in reproductive health. These findings highlighted the potential of SP-EVs as biomarkers for semen quality, their role in protecting sperm functions under seasonal stress, and epigenetic mechanisms, providing critical insights for improving the reproductive performance of buffalo bulls under climate-induced stress.
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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 | 0.000 |
| 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 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".