O'Meara C M, Donovan A, Hanrahan J P, Duffy P, Fair S, Evans A C O, Lonergan P
School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Lyons Research Farm, Newcastle, County Dublin, Ireland.
Theriogenology. 2007 Apr 15;67(7):1262-8. doi: 10.1016/j.theriogenology.2007.01.012. Epub 2007 Mar 2.
The role of seminal plasma (SP) components on the maintenance of motility, viability and fertilising ability of frozen-thawed spermatozoa is of considerable interest. However, differences observed in constituents of SP among males could explain differences in fertility obtained in vivo. Two experiments were designed to examine the effects of seminal plasma on fertility from cervically inseminated frozen-thawed semen. The objective of Experiment 1 was to investigate if source or type of SP influences pregnancy rate. Seminal plasma was collected from rams previously classified as having either High (HSP; n=3) or Low (LSP; n=3) fertility in vivo. Artificial SP (fructose/sodium solution with 10% BSA; ASP) was made. Frozen semen from the same 6 rams was thawed and inseminated (Control) or resuspended either in HSP, LSP or ASP (20% in semen) prior to insemination of ewes (n=284, over 2 farms). The overall pregnancy rate was 28.1%. Treatments (Control, ASP, HSP and LSP) were not significantly different (P>0.3). There was no difference between HSP and LSP (P>0.5), and no effect of using ASP compared to ram SP (P>0.7), on pregnancy rate. As there was no effect of SP on pregnancy rate a repeat experiment (Experiment 2) was designed to test the effect of washing and selecting motile sperm prior to resuspending in phosphate-buffered saline (PBS) containing SP on pregnancy rate. Frozen-thawed semen from each of 2 rams was centrifuged through a density gradient, pellets were centrifuged through a wash medium and the sperm concentration/ram was counted. Sperm cells were resuspended in: (1) control PBS, (2) PBS containing 30% HSP or (3) PBS containing 30% LSP to give 100 x 10(6) motile sperm in 0.25 mL. Control straws were thawed and inseminated directly. Ewes (n=223 over 2 farms) were inseminated 57 h post-sponge withdrawal and those not returning to oestrus were slaughtered 29-50 days post-insemination for pregnancy determination. In Experiment 2, the pregnancy rate for Control, PBS, HSP and LSP were 15.4%, 2.3%, 0% and 0%, respectively, for Farm 1 (P>0.05) and 17.8%, 11.0%, 3.9% and 12.4%, respectively, for Farm 2. Under the conditions of the current study, addition of SP from different donors of either High or Low fertility status to frozen-thawed ram semen post-thawing did not improve pregnancy rate in ewes. ASP had no effect on pregnancy rate in ewes when added to frozen-thawed semen. Washing and selection of motile sperm prior to resuspension in PBS with or without SP (30%) before insemination had a negative effect on pregnancy rate in cervically inseminated ewes. Hence, the addition of seminal plasma or some of its constituents to semen does not appear to improve pregnancy rate in cervically inseminated ewes.
精浆（SP）成分对冻融精子活力、生存能力和受精能力维持的作用备受关注。然而，雄性之间精浆成分的差异可能解释体内受精率的差异。设计了两个实验来研究精浆对经宫颈授精的冻融精液生育力的影响。实验1的目的是研究精浆的来源或类型是否影响妊娠率。精浆取自先前在体内被分类为高生育力（HSP；n = 3）或低生育力（LSP；n = 3）的公羊。制备了人工精浆（含10%牛血清白蛋白的果糖/钠溶液；ASP）。将来自相同6只公羊的冷冻精液解冻并授精（对照），或在给母羊授精前（2个农场共n = 284只），将其重悬于HSP、LSP或ASP中（精液中的比例为20%）。总体妊娠率为28.1%。各处理组（对照、ASP、HSP和LSP）之间无显著差异（P>0.3）。HSP和LSP之间无差异（P>0.5），与公羊精浆相比，使用ASP对妊娠率无影响（P>0.7）。由于精浆对妊娠率无影响，设计了重复实验（实验2）来测试在含有精浆的磷酸盐缓冲盐水（PBS）中重悬前，洗涤和选择活动精子对妊娠率的影响。将2只公羊的冻融精液通过密度梯度离心，沉淀通过洗涤介质离心，并计数每只公羊的精子浓度。精子细胞重悬于：（1）对照PBS，（2）含30%HSP的PBS或（3）含30%LSP的PBS中，使0.25 mL中有100×10⁶个活动精子。对照细管解冻后直接授精。在撤栓海绵后57小时给母羊授精（2个农场共n = 223只），未返情的母羊在授精后29 - 50天屠宰以确定妊娠情况。在实验2中，农场1对照、PBS、HSP和LSP的妊娠率分别为15.4%、2.3%、0%和0%（P>0.05），农场2分别为17.8%、11.0%、3.9%和12.4%。在本研究条件下，解冻后向冻融公羊精液中添加来自不同生育力状态（高或低）供体的精浆并不能提高母羊的妊娠率。将ASP添加到冻融精液中对母羊妊娠率无影响。在授精前，在有或无精浆（30%）的PBS中重悬前洗涤和选择活动精子对经宫颈授精母羊的妊娠率有负面影响。因此，向精液中添加精浆或其某些成分似乎并不能提高经宫颈授精母羊的妊娠率。
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