中文摘要：

本试验选用63头长白-大白杂交初产母猪，研究营养水平对初产母猪妊娠早期胚胎存活和瘦素（leptin）、孕酮分泌及胚胎瘦素、瘦素受体（Ob-R）、信号传导和转录活化因子-3（STAT-3）、孕酮受体（PGR）、DNA甲基化转移酶-1（DNMT-1）基因表达的影响。将配种后的母猪随机分到高、中、低3个营养水平组按2倍、1．2倍和0．6倍维持需要（分别记为2．0M、1．2M和0．6M）供给饲粮，妊娠12、25和35d屠宰母猪收集血清和胚胎，用ELISA方法测定血清中瘦素、孕酮水平，用RT-PCR方法研究目的基因在胚胎中的表达差异。结果表明：①胚胎存活率，妊娠12、25和35d时，1．2M组均显著高于2．0M组（P〈0．05）；1．2M组妊娠12d时与0．6M组间差异不显著（P〉0．05），而妊娠25、35d高于0．6M组（P〈0．05）；②血清瘦素水平，妊娠12d时，2．0M组显著高于1．2M组（P〈0．05），极显著高于0．6M组（P〈0．01）；妊娠25和35d时，2．0M组极显著高于1．2M和0．6M组（P〈0．01）；1．2M组极显著高于0．6M组（P〈0．01）。血清孕酮水平，妊娠12、25和35d时，2．0M组极显著低于1．2M组和0．6M组（P〈0．01），1．2M组和0．6M组之间差异不显著（P〉0．05）；③营养水平对胚胎存活重要基因表达的影响，leptin和Ob-R基因mRNA的相对表达量在妊娠12、25和35d时，2．0M组显著高于1．2M和0．6M组（P〈0．05），而1．2M与0．6M组差异不显著（P〉0．05）。妊娠12和25d时，2．0M组胚胎STAT-3基因的相对表达极显著高于0．6M组（P〈0．01）；妊娠35d时，2．0M和1．2M组极显著高于0．6M组（P〈0．01）。妊娠12、25和35d时，2．0M组胚胎DNMT-1的相对表达显著高于0．6M组（P〈0．05）。妊娠12d时，各水平组胚胎PGR表达差异不显著（P〉0．05），妊娠25d时，0．6M组极显著高于2．0M组（P〈0．01），显著高于1．2M组（P〈0．05），妊娠35d时?

英文摘要：

Sixty three crossbred gilts （Landrace × Yorkshire） were used to investigate the effects of nutrition levels on the embryonic survival, secretion of leptin and progesterone and mRNA expression of leptin, obesity receptor （Ob-R）, signal transducer and activator of transcription-3 （STAT-3）, progesterone receptor （PGR） and DNA methyltransferase-1 （DNMT-1） in embryos during early pregnancy of gilts. The gilts were randomly divided into 3 nutrition levels （High： 2 × maintenance nutrition （2M） ; Medium： 1.2 × maintenance nutrition （1.2M） ; Low： 0.6×maintenance nutrition （0. 6M）） after mating. Gilts were killed on the 12^th , 25^th and 35^th day of pregnancy, and the serum and embryos were collected. Enzyme-linked immuneosorbent assay （ELISA） was applied to determine the leptin and progesterone concentration in serum, and real-time polymerase chain reaction （RT-PCR） was applied to determine gene expression in embryos. The results showed that （1） Embryonic survivals on the 12^th, 25^th and 35^th day of pregnancy in 1.2M group were significantly higher than that of 2.0M group （P〈0. 05） and no significant difference was obtained between 1.2M group and 0. 6M group on the 12^th day （P〉0. 05）, but embryonic survivals in 1.2M group on the 25^th and the 35^th day were higher than that of 0. 6M group （P〈0. 05）. （2） On the 12^th day of pregnancy, leptin concentrations of serum in 2. 0M group were significantly higher than that in 1.2M group （P〈0. 05） and very significantly higher than that in 0.6M group （P〈0. 01） ; on the 25^th day and 35^th day of pregnancy, leptin concentrations of serum in 2.0M group were very significantly higher than that in 1.2M group and 0. 6M group （P〈0. 01）, and leptin concentrations of serum in 1.2M group were very significantly higher than that in 0. 6M group （P〈0. 01）. Progesterone concentrations of serum in 2.0M group were very significantly lower than that in 1.2M group and 0. 6M group （P〈0. 01