GIANT PANDA SPERM TOLERATE CRYOPRESERVATION AT RAPID FREEZING AND THAWING RATES
Notice bibliographique
Résumé
Many individuals in the ex situ giant panda (Ailuropoda melanoleuca) population do not reproduce, largely due to behavioral deficiencies. Artificial insemination is an important assisted breeding tool for genetically managing this species. To optimize sperm cryopreservation, this study compared three cryomethods and three thawing temperatures. Ejaculates (n = 28) from five adult (5.5 to 20.5 y) giant pandas were assessed for sperm traits, diluted in a TEST egg-yolk diluent containing 3.3% glycerol, cooled slowly to 5°C over 4 h, loaded in 0.25 ml straws and cryopreserved using a (1) manual two-step method, (2) automated Cryomed and (3) field-ready dry shipper. For the two-step method, samples were placed 7.5 cm above liquid nitrogen for 1 min (− 35°C/min), then 2.5 cm above liquid nitrogen for 1 min (− 100°C/min) before plunging. Using a programmable freezer (Forma Cryomed), sperm were frozen at − 40°C/min, then −100°C/min. For the field-ready method, samples were placed directly into a dry shipper for 10 min (− 35°C/min). Samples were thawed in a waterbath at (1) 22°C for 30 sec, (2) 37°C for 30 sec or (3) 50°C for 10 sec. Each aliquot then was diluted in Ham's F10 culture medium at 37°C and incubated for 24 h. Samples were assessed for sperm motility (0–100%), forward progression (scale, 0–5; 5 is best), intact acrosomes (0–100%) and longevity quotient (initial motility ÷ absolute gradient of motility decline over 24 h). Mean (± SEM) fresh ejaculate traits were: sperm motility, 83.2 ± 1.3%; forward progression, 4.0 ± 0.1; and intact acrosomes, 86.4 ± 1.4%. Cryomethod influenced (P < 0.05) giant panda sperm quality. Post-thaw sperm motility was similar (P > 0.05) among the two-step (65.7 ± 2.0%), dry shipper (61.1 ± 2.3%) and Cryomed (58.5 ± 2.4%). Sperm progression post-thaw also did not differ (P>0.05) among cryomethods (range, 3.0 to 3.3). Post-thaw intact acrosomes were highest (P < 0.05) in the two-step (53.0 ± 2.1%) and dry shipper (50.6 ± 2.4%) compared to the Cryomed (44.2 ± 2.5%). The longevity quotient was higher (P < 0.05) in the dry shipper (25.8 ± 3.1) than the Cryomed (16.7 ± 1.5), and both were similar (P > 0.05) to the two-step (21.5 ± 1.5). Thawing temperature also influenced (P < 0.05) giant panda sperm quality. Post-thaw sperm motility was higher (P < 0.05) when thawed at 50°C (67.5 ± 2.2%) compared to 22°C (56.7 ± 2.2%), and both were similar (P > 0.05) to 37°C (62.7 ± 2.2%). Sperm progression post-thaw was better (P < 0.05) in samples thawed at 50°C (3.4 ± 0.1) compared to 37°C (3.0 ± 0.1) or 22°C (3.0 ± 0.1). Thawing temperature had no influence (P > 0.05) on intact sperm acrosomes (range, 47.6% to 51.9%) or longevity quotients (range, 16.8 to 23.6). These data illustrate that optimal post thaw sperm quality in the giant panda is achieved with the manual two-step or dry shipper technique using a 50°C thawing temperature. This demonstrates that giant panda sperm can tolerate a rapid freezing rate (−35 to −100°C/min) in conjunction with a high thawing temperature (50°C). This finding suggests the possibility of successfully cryopreserving giant panda sperm in the field using the simple dry shipper technique. (Supported by the Morris Animal Foundation and the Friends of the National Zoo). (poster)
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,000 |
| 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 ».