[Effect of equine follicular fluid and bovine somatotropin in the survival of ovine embryos asynchronously transferred] | Efecto del liquido folicular equino y la somatotropina bovina en la sobrevivencia de embriones ovinos transferidos asincronicamente

Inglés. Maternal-embrionary asynchrony could be overcome by increasing progesterone (P4) levels to improve embryo development or by delaying luteolisis. With this aim, asynchronous recipients were treated wlth bovine somatotropin (ST) or equine folllcular fluid (EFF). Six day embryos were collected from 25 donors. Estrous was synchronized with fluorogestone acetate and PGF2 alpha. Progestagen was removed in asynchronous recipients 3.5 days before the donors. Recipients were alocated to 5 groups: synchronous (syn), n= 15; asynchronous (asyn), n= 16; asynchronous + EFF (asyneff), n= 19; asynchronous + ST (asynst), n=7 and asynchronous + EFF + ST (asynffst), n= 10. Progesterone levels were higher (3.3 ng/ml) in asyneff recipients (PO.05), and the lowest levels (1.4 ng/ml) were found in the asynst ones. Luteal phase was longer (16.8 days) in the non pregnant ewes of the asyn group. Luteolisis was delayed in 4 ewes of the asyneff until day 19. Pregnancy rate was not different between the syn and asyn groups (86.6 vs. 68.7%). Treatment with EFF and ST did not improve pregnancy rates in asynchronous recipients even when P4 levels were increased in pregnant asyneff and asynffst recipients or when luteolisis was delayed in the asyneff ones

Español; castellano. La asincronia materno-embrionaria pudiera resolverse incrementando los niveles de progesterona (P4) para promover el desarrollo embrionario, o retrasando la luteolisis. Para tal fin se administro somatotropina bovina (ST), liquido folicular equino (LFE) o ambos, a receptoras de embriones en asincronia. Se recolectaron embriones en 25 donadoras el dia 6 posestro. Las receptoras se sincronizaron con acetato de fluorogestona y PGF2 alfa, y en las asincronicas de todos los grupos se retiro el progestageno 3.5 dias antes que en las donadoras. Se dividieron en cinco tratamientos: sincronia (sin), n = 15; asincronia (asin), n = 16; asincronia + LFE (asinlfe), n = 1 g; asincronia + ST (asinst), n = 7; y asincronia + LFE + ST (asinlfst), n = 1 0. Las concentraciones de progesterona (3.3 ng/ml) fueron mayores en el grupo asinlfe (PO.05). Las menores concentraciones (1.4 ng/ml) se presentaron en el asinst. La fase lutea de mayor duracion, 16.8 dias promedio, se presento en las no gestantes del grupo asin. En cuatro ovejas del asinlfe se retraso la luteolisis hasta el dia 19. La fertilidad del grupo sin (86.6%) no fue diferente a la del asin (68.7%). Los tratamientos no mejoraron la fertilidad a pesar de incrementarse la P4 en las gestantes asinlfe y asinlfst o retrasarse la luteolisis en las asinlfe. Se propone que antes de modificar la asincronia materno-embrionaria se determine el grado de asincronia tolerable de manera naturla en los ovinos