Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Miguel Servet 177, C.P. 50013 Zaragoza, Spain.
Anim Reprod Sci. 2013 Sep;141(1-2):52-61. doi: 10.1016/j.anireprosci.2013.07.007. Epub 2013 Jul 26.
The effect of exogenous melatonin on embryo viability in undernourished ewes was investigated. At lambing, 24 ewes were treated (+MEL) or not (-MEL) with a melatonin implant. After 45 days, both groups were fed to provide 1.5 (Control, C) or 0.5 (Low, L) times daily maintenance requirements, so that experimental groups were: C-MEL, C+MEL, L-MEL and L+MEL. Ewes were mated (Day 0) and on Day 5 embryos were recovered and classified according to their developmental stage and morphology. Ovaries were used for in vitro fertilization and uterine horns were processed to study progesterone and oestrogen receptor (PR and ERα) expression by inmunohistochemistry. After 21 days, groups L-MEL and L+MEL had an average weight loss of 10kg (P<0.001). Number of viable embryos per CL from L+MEL (0.50±0.2) was higher than from other groups (P<0.05). Overall, the melatonin effect was particularly evident in undernourished ewes, increasing both viability (L+MEL: 65%; L-MEL: 25%; P<0.05) and pregnancy rates (L+MEL: 66.6%; L-MEL: 16.6%; P<0.05). Neither nutrition and melatonin nor their interaction had a significant effect on the in vitro oocyte development. Melatonin treatment tended to increase the percentage of positive cells to PR in deep glandular epithelium, independently of diet (P=0.09), and the greatest staining intensity of PR was observed in the luminal and superficial glandular epithelia (P<0.0001). In conclusion, melatonin implants at lambing during the breeding season improve the viability of embryos recovered from undernourished ewes, although this effect seems not to be mediated at the oocyte competence level.
研究了外源性褪黑素对营养不足母羊胚胎活力的影响。在产羔时，24 只母羊接受（+MEL）或不接受（-MEL）褪黑素植入物治疗。45 天后，两组均进行饲养，提供 1.5（对照，C）或 0.5（低，L）倍每日维持需要量，使实验组为：C-MEL、C+MEL、L-MEL 和 L+MEL。母羊配种（第 0 天），第 5 天回收胚胎并根据其发育阶段和形态进行分类。对卵巢进行体外受精，处理子宫角以通过免疫组织化学研究孕激素和雌激素受体（PR 和 ERα）的表达。第 21 天，L-MEL 和 L+MEL 组平均体重减轻 10kg（P<0.001）。来自 L+MEL 的每个黄体的存活胚胎数（0.50±0.2）高于其他组（P<0.05）。总体而言，褪黑素在营养不足的母羊中效果更为明显，既提高了胚胎的活力（L+MEL：65%；L-MEL：25%；P<0.05）又提高了妊娠率（L+MEL：66.6%；L-MEL：16.6%；P<0.05）。营养和褪黑素及其相互作用对体外卵母细胞发育均无显著影响。褪黑素处理倾向于增加深层腺上皮中 PR 阳性细胞的百分比，而与饮食无关（P=0.09），并且在腔和浅层腺上皮中观察到 PR 的最大染色强度（P<0.0001）。总之，在繁殖季节产羔时植入褪黑素可提高从营养不足的母羊中回收的胚胎的活力，尽管这种作用似乎不是在卵母细胞能力水平上介导的。
