黄体期短期优饲对道寒杂交羊卵泡发育的影响

Effect of short-term nutritional supplementation on follicular development in Dorset×Han crossbred sheep

为研究母羊黄体期短期优饲对其卵泡发育的影响。选择60只道寒杂交羊随机分为试验组和对照组,每组30只。试验羊均先饲喂基础日粮(DE 11.72 MJ/d,DP 79.71 g/d),并对试验羊进行同期发情处理(肌注PG 0.1 mg,3 d后阴道埋置CIDR 12 d,撤栓再次肌注PG 0.1 mg),同期发情处理埋栓2 d后试验组羊饲喂试验日粮(DE 18.75 MJ/d,DP 108.44 g/d),饲喂期10 d,并于饲喂开始第1,2,4,6,8,10天分别采集试验组和对照组羊颈静脉血,测定血浆中葡萄糖,胰岛素,瘦素等含量。在撤栓注射PG后,埋栓第13,14,15天每组随机选择6只羊进行屠宰,采集卵巢,按小卵泡(≤3.0 mm)、中等卵泡(3.0～5.0 mm)和大卵泡(≥5.0 mm)进行卵泡数量统计及卵泡液、颗粒细胞收集。采用实时定量PCR技术,分析不同大小卵泡颗粒细胞中OB-R和IGF-1基因mRNA表达水平。结果显示,与对照组相比,试验组小卵泡数量显著下降(P<0.01),中等卵泡和大卵泡数量显著升高(P<0.01),同时血浆和大卵泡中葡萄糖(P<0.01)、胰岛素(P<0.01)和瘦素(P<0.05)的平均浓度均显著升高,中等卵泡和大卵泡颗粒细胞中OB-R和IGF-1基因的表达显著上升(P<0.05)。结果表明,母羊黄体期短期优饲可提高血浆中葡萄糖、胰岛素、瘦素浓度和颗粒细胞中OB-R和IGF-1基因表达量,促进卵泡期的卵泡优势化数量。

The study was to evaluate the effects of short-term nutritional supplementation on follicular development during luteal phase in ewes.60 Dorset×Han crossbred ewes were divided randomly into two groups of control(n=30) and treatment(n=30).All ewes were fed on basal diet(DE 11.72 MJ/d;DP 79.71 g/d) originally.Then ewes was treated to oestrus synchronization(3 d after intramuscularly injection of PG 0.1 mg,CIDR for 12 d,then PG injection again for the same dose on the day of removal of CIDR).From day 2 of CIDR embedment,a high-energy supplement diet(DE18.75 MJ/d;DP 108.44 g/d) was fed to the treatment group for 10 d.Plasma metabolites(glucose,insulin,leptin)of control and treatment group were measured on day 1,2,4,6,8,10 during supplementation.The numbers of the follicles were counted in categories of small follicle(≤3.0 mm),medium follicle(3.0-5.0 mm) and large follicles(≥5.0 mm) and the follicular fluid and granulose cells were collected respectively,the expression of mRNA of OB-R and IGF-1 were detected in follicular granulose cells by real-time PCR on day 13,14,and 15 of six ewes respectively.Compared with control,the numbers of medium follicles and large follicles significantly increased (P<0.01),whereas the numbers of small follicles significantly decreased(P<0.01)in treatment group.Meanwhile,the mean concentrations of glucose(P<0.01),insulin(P<0.01)and leptin(P<0.05)in plasma and large follicles increased significantly.The expression level of OB-R and IGF-1 increased significantly in granulose cells of medium and large follicles.The short-term nutritional supplementation during luteal phase improves the numbers and dominance of large follicles through increasing the levels of glucose,insulin,leptin in plasma and the expression of OB-Rand IGF-1 mRNA.