精准定时输精对后备母猪早期胚胎发育与繁殖性能的影响

为探讨精准定时输精(fixed-time artificial insemination, FTAI)对后备母猪早期胚胎发育和繁殖性能的影响,试验1选取自主培育的金乌猪后备母猪43头,随机分为2组,其中,对照组24头,为自然发情,观察后人工配种(artificial insemination, AI);试验组19头,为精准定时输精组。分别于0 h(停喂烯丙孕素)、42 h 肌注孕马血清促性腺激素(pregnant mare serum gonadotropin, PMSG)]、122 h 肌注促性腺激素释放激素(gonadotropin releasing hormone, GnRH)]静脉采血,检测孕酮(progesteron, P4)、雌二醇(estradiol, E2)、促卵泡激素(follicle-stimulating hormone, FSH)和黄体生成素(luteinizing hormone, LH)的含量;在配种后33 h,分别屠宰对照组和试验组4头后备母猪,回收受精卵进行体外培养,其余后备母猪继续饲养并进行分娩与产仔情况追踪。结果显示,从停喂烯丙孕素至42 h和122 h,P4值呈下降趋势但差异不显著(P>0.05);停喂烯丙孕素至停喂后42 h,E2值从80 pmol·L^-1显著(P<0.05)下降至58.3 pmo·L^-1,而在PMSG作用后又急剧升至134.07 pmol·L^-1(P<0.01);FSH值未见显著变化(P>0.05);停喂烯丙孕素至停喂后42 h,LH值由0.09 IU·L^-1升至0.12 IU·L^-1(P>0.05),PMSG作用后又降至0.09 IU·L^-1(P>0.05),呈先升后降的趋势,符合正常生理周期的变化趋势,表明用药合理无副作用。屠宰后卵巢排卵点计数结果显示,试验组17.5枚,对照组15.25枚,差异不显著(P>0.05);试验组平均窝均总产仔数、活仔数与对照组相比未见显著差异,但相对提高1.05头。试验2选取大长后备母猪189头,处理方式同试验1,随机分为试验组94头、对照组95头,试验组活仔较对照组约提高0.58头(P>0.05),断奶成活率提高2.99百分点。综上所述,精准定时输精程序处理符合母猪生理发情周期特质,可增加排卵数且对早期胚胎发育无不良影响,在提高后备母猪的利用率、增加窝均活仔数和提高仔猪断奶成活率等方面都有一定的积极作用,值得进一步优化研究和推广应用。

Effect of fixed-time artificial insemination on earlier embryonic development and reproduction performance in gilts

To explore the effect of fixed-time artificial insemination (FTAI) on earlier embryonic development and fertility of gilts, in experiment 1, totally 43 gilts (Jinwu pig) were randomly divided into control (n=24) and FTAI groups (n=19). The control group were natural estrus, and performed artificial insemination (AIs) after a standing reflex, and the FTAI group were performed AIs after administration of altrenogest+pregnant mare serum gonadotropin (PMSG)+gonadotropin releasing hormone (GnRH) (ALT+PMSG+GnRH). Blood samples were collected for detecting of the concentration of progesteron (P4), estradiol (E2), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) at 0 h (stop feeding altrenogest), 42 h (intramuscular injection of PMSG) and 122 h (intramuscular injection of GnRH). Four gilts of each group were slaughtered at 33 h after AIs, and the fertilized eggs were recovered for in vitro culture, the remaining gilts were used to observe the fertility. The results showed that concentration of progesterone were downregulated from 0 h to 122 h, but there was no significant difference(P>0.05). Estradiol levels were dropped from 80 pmol·L^-1 to 58.3 pmol·L^-1 (P<0.05) during 0 h to 42 h, but dramatically increased to 134.07 pmol·L^-1 from 42 h to 122 h (P<0.01). FSH value showed no significant difference (P>0.05). The concentration of luteinizing hormone increased gradually from 0.09 IU·L^-1 to 0.12 IU·L^-1, and decreased to 0.09 IU·L^-1 at these three time points, showing a up and down trend, which conformed the trend of normal physiological cycle, indicating the administration was reasonable and had no side effects. The ovaries were collected from the control and FTAI groups at 33 h after AIs, the ovulation point were counted, showing that there was no significant difference (P>0.05) between FTAI group (17.5) and control group (15.25). Meanwhile, compared with the control group, the litter size and alive litter size of FTAI group did not show significant difference (P>0.05), but the litter size and alive litter size of FTAI group were all increase of 1.05 heads relatively. In experiment 2, totally 189 gilts (Yorkshire×Landrace) were randomly divided into control (n=95) and FTAI groups (n=94). The alive litter size of FTAI group was increased 0.58 heads, and the weaning survival rate increased 2.99 percentage point compared with the control group. In summary, the administration of FTAI procedure was conforming to the characteristics of gilts physiological estrous cycle, and might increase the ovulation number without adverse effects on the earlier embryos development. Meanwhile, the FTAI procedure had a positive effect on improving the utilization of gilts and increasing the alive litter size and survival rate of weaning piglets to a certain degree, which was worthy of further optimization, promotion and application.