22 Strategies for oocyte collection procedures in free-roaming bison herds
Notice bibliographique
Résumé
The study was conducted to test the feasibility of protocols for field collection of cumulus–oocyte complexes (COC) for in vitro embryo production (IVP) in wild bison. The study was done with captive wood bison during the late anovulatory season (July). In Experiment 1, bison were assigned randomly to 2 groups (n = 8/group) in which transvaginal ultrasound-guided COC collection was done in a chute without sedation or in lateral recumbency after chemical immobilization using a dart gun to compare collection efficiencies. In Experiment 2, a 2 × 2 design was used to examine the effects of superstimulation treatments [single-dose equine chorionic gonadotrophin (eCG) vs. multiple-dose FSH] and methods of drug administration (manual injection vs. field darting) on COC collection and IVP. Initial COC collection was done to serve as a non-superstimulated random start and to synchronize follicular wave emergence on the following day (Day 0; n = 16). Half of the bison were given a single dose of 5000 IU of eCG intramuscularly (IM) on Day −1. The other half were given 200 mg of FSH IM on Day 0 and Day 2, followed by 2000 IU human chorionic gonadotrophin IM on Day 4. Superstimulatory treatments were given by manual injection (chute restrained) to half of the bison in each group and by field darting in the other half. The COC were collected on Day 4 in the eCG group and Day 5 in the FSH group. Recovered COC were matured in vitro for 25 to 28 h at 38.8°C, fertilized (2 × 106 sperm mL−1) and co-incubated at 38.8°C in 5% O2, 5% CO2, and 90% N2 for 18 h. Presumptive zygotes were denuded and cultured at 38.8°C in 5% O2, 5% CO2, and 90% N2. A commercially available IVF media set was utilised (IVF Bioscience). Data were compared by ANOVA and GLIMMIX. In Experiment 1, no difference was detected between chute-restrained vs. chemically immobilized groups in the time required to complete COC collection (6.9 ± 1.0 vs. 8.9 ± 1.0 min; P = 0.2), the number of follicles aspirated (11.5 ± 1.9 vs. 9.3 ± 1.8; P = 0.4), or the COC recovery rate [COC recovered/follicle aspirated; 58/92 (63%) vs. 44/69 (64%); P = 0.9]. In Experiment 2, no differences were detected between superstimulation treatments (eCG vs. FSH) or method of drug administration (manual injection vs. field darting) for any endpoint. The number of medium (4.5–7.5 mm; 9.5 ± 1.0 vs. 2.5 ± 0.6; P < 0.0001) and large (>8 mm; 8.6 ± 0.8 vs. 3.4 ± 1.5; P = 0.004) follicles available was greater after superstimulation (groups combined) than without superstimulation (random start). Although there was no difference in the number of recovered compact COC between the superstimulated and non-superstimulated bison (8.9 ± 1.3 vs. 6.2 ± 1.7; P = 0.2), the embryo production rate (number of embryos produced/number of COC matured) was greater after superstimulation than without superstimulation [54/189 (39%) vs. 19/108 (18%); P < 0.05]. We conclude that COC collection in a field setting is feasible and minimum-handling superstimulation with a single dose of eCG is as effective as a multiple-dose FSH protocol for the in vitro production of embryos in bison. This research was supported by NSERC and Vetoquinol.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».