Datos del Documento
|Título :||Genetic diversity loss due to selection for scrapie resistance in the rare Spanish Xalda sheep breed|
|Autor :||Álvarez, Isabel|
Royo Martín, Luis J.
Gutiérrez, Juan P.
Arranz, J. J.
|Palabras clave :||Genetic variability|
|Fecha de publicación :||sep-2007|
|Citación :||Álvarez, I.; Royo, L. J.; Gutiérrez, J. P.; Fernández, I.; Arranz, J. J.; Goyache, F. Genetic diversity loss due to selection for scrapie resistance in the rare Spanish Xalda sheep breed. Livestock Science. 2007; 111 (3): 204-212.|
|Resumen :||Lipid contained in embryonic cells can adversely affect survival of frozen/thawed in vitro produced (IVP) bovine embryos (Leibo et al, Theriogenology 43:265, 1995). Moreover, glycogen accumulates in excess in cells from IVP mouse embryos (Ozias and Stern, Biol Reprod, 8:467-472, 1973) and could retain water and render difficult the dehydration when freezing embryos. Mobilizing these stocks could therefore increase the ability of IVP embryos to be cryopreserved and it is known that epinephrine causes lipid and glycogen breakdown in adult tissues. Degradative products of glycogen and lipids could be used by the embryo depending on the presence of other energy substrates in the culture medium.The effects of epinephrine on the freezability of IVP embryos were evaluated. Cumulus-oocyte complexes (COCs) were matured in TCM 199, 10% fetal bovine serum (FBS) and FSHp (20 g/ml) for 24 h. Culture conditions were 39o C, 5% CO2 in air and high humidity. Matured COCs were incubated together with Percoll-separated sperm in Fert-TALP and 10 g/ml heparin for 20 h. Zygotes were vortexed for 2 min, allotted to each group and cultured in mSOF, 3g/L BSA and 10% FBS. The effect of 1M epinephrine during the initial 48 h of culture was determined in a 2 x 2 factorial design in presence (+LP) or absence (-LP) of lactate (3.3 mM) and pyruvate (0.3 mM) in mSOF. From 48 h to Day 7, culture in all groups was performed in mSOF+LP without epinephrine. Day 7 blastocysts were slowly frozen in PBS and 1.5 M ethylene glycol, thawed for 5 sec in air and 30 sec in water at 30 oC and directly rehydrated in PBS. Thawed blastocysts were cocultured for 48 hours with bovine oviductal cells. Morphological normality at thawing and blastocoelic re-expansion were the criteria for survival. Data were analyzed by ANOVA and REGWF test for means. No interactions between epinephrine and LP were detected.Both, presence of epinephrine and absence of LP during the first 48 hours of culture significantly decreased blastocyst rate. Survival rate after thawing was not altered by these treatments.|
|Aparece en las colecciones:||Agroalimentación y Ganadería|
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