Two cases of reciprocal translocations in domestic pigs producing small litters

SUMMARY: Two boars of Finnish Yorkshire breed were selected for chromosomal analysis because of their small litters. One had a complex three breakpoint reciprocal translocation where the small distal chromosome segments were fused in new combinations between autosomes 2,9 and 14. This boar with a 2n = 38,XY,t(2;9;14)(q23;q22;q25) karyotype had produced approximately 3.3 piglets per litter and its fertility was reduced by 70% compared to average of litter size in Finnish Yorkshire breed pigs. In another Finnish Yorkshire breed boar, the long arm of autosome 7 had broken and attached to the terminal end of autosome 15. The boar had a 2n = 38,XY, rcp(7q-;15q+)(q24;q26) karyotype. The average of piglets per litter sired by this boar was 5.2 and the litter size was reduced by approximately 50%. The chromosomal rearrangements t(2;9;14) was inherited by four of the boar's offspring studied from two whole litters having seven piglets altogether. Meiotic chromosomes were analysed conventionally from one male translocation carrier offspring of the t(2;9;14) boar. Total sperm count and progressive motility of spermatozoa were within normal limits in one male translocation carrier offspring of the t(2;9;14) boar and in the rcp(7q-;15q+) boar. The two reciprocal translocations seem to have arisen spontaneously in these two boars. ZUSAMMENFASSUNG: Zwei F?lle reziproker Translokationen bei Ebern mit kleinen Nachkommen Würfen Von zwei Finnischen Yorkshire Ebern hatte einer drei komplexe reziproke Translokationen, wo kurze distale Chromosomensegmente zu neuen Kombinatioenen zwischen Autosomen 2, 9 und 14 fusioniert waren. Der Eber mit 2n = 38,XY,t(2;9;14)(q23;q22;q25) Karyotyp hatte Nachkommenwürfe mit etwa 3.3 Ferkel weniger und 70% Fruchtbarkeit der bei dieser Rasse normalen. In einem anderen Eber war der lange Arm von Chromosom 7 gebrochen und am Ende von Chromosom 15: 2n = 38,XY, rcp(7q-; 15q+)(q24;q26) Karyotyp. Nachkommenwurfgr??e war 5.2. Das chromosomale Rearrangement t(2;9;14) wurde an 4 Nachkommen in zwei Würfen mit zusammen 7 Ferkel vererbt. Meiotische Chromosomen wurden bei einem m?nnlichen Translokationstr?ger dieser Nachkommen analysiert. Gesamtspermienenzahl und ihre Vorw?rtsbewegung waren in normalen Grenzen bei diesem Nahkommen ebenso wie beim rcp(7q-;15q+) Eber. Die zwei reciproken Translokationen scheinen spontan entstanden zu sein.     

Pharmacokinetic investigations of the marker active metabolites 4‐methylamino‐antipyrine and 4‐amino‐antipyrine after intramuscular injection of metamizole in healthy piglets

Metamizole (MT) is a pyrazolone nonsteroidal anti‐inflammatory drug labelled for humans and animals. The aim of this study was to assess the pharmacokinetics of its active metabolites 4‐methylamino‐antipyrine (MAA) and 4‐amino‐antipyrine (AA) in male piglets after a single intramuscular injection of MT. Eight healthy male piglets were administered MT (100 mg/kg) intramuscularly. Blood was sampled at scheduled time intervals, and drug plasma concentrations evaluated by a validated HPLC method. MAA and AA plasma concentrations were quantitatively detectable from 0.25 to 48 h and 0.50 to 72 h, respectively, in 6 of 8 and 7 of 8 animals. The average maximum concentrations of MAA and AA were of 47.59 and 4.94 mg/mL, respectively. The average half‐lives were 8.57 and 13.3 h for MAA and AA, respectively. This study showed that the amount of MAA and AA produced in piglets is different to that in the animal species previously investigated. Further studies are necessary to understand whether these differences in MAA and AA plasma concentrations between animal species necessitate diverse therapeutic drug dosing.     

玻璃化冷冻牛卵母细胞单精子注射后体外发育能力的研究

实验研究了不同成熟培养时间的牛卵母细胞玻璃化冷冻及胞质内单精子注射(ICSI)后的受精效果。结果表明:成熟后的新鲜牛卵母细胞按照ICSI注射方法穿刺而不注射精子组与未经穿刺的对照组相比,孤雌激活后的卵裂率、囊胚发育率及囊胚细胞数无显著差异(P>0.05);成熟培养16h(MⅠ)和23h(MⅡ)卵母细胞冷冻解冻后形态正常率均显著低于新鲜对照组(76.66%、87.33%vs100.0%)(P<0.05),冷冻解冻后二者分别成熟培养至24h,ICSI后胚胎的囊胚发育率(5.29%、14.41%)显著低于新鲜对照组(24.40%)(P<0.05);成熟培养23h与成熟培养16h的卵母细胞冷冻解冻后形态正常率及ICSI后囊胚发育率(14.41%vs5.29%)均有显著性差异(P<0.05)。实验证明,ICSI操作不会影响卵母细胞发育潜力;玻璃化冷冻影响卵母细胞解冻后形态正常率以及ICSI后胚胎的发育能力;成熟培养23h比16h的卵母细胞冷冻保存后经ICSI的胚胎发育潜力高。     

Sperm Pretreatment with Dithiothreitol Increases Male Pronucleus Formation Rates After Intracytoplasmic Sperm Injection (ICSI) in Swamp Buffalo Oocytes

Failure of male pronucleus formation has hampered the success of intracytoplasmic sperm injection (ICSI) in swamp buffalo. The aim of the present study was to improve male pronucleus formation by pretreating sperm with various chemicals before ICSI. In Experiments1 and 2, sperm were treated according to one of the following protocols: (1) 0.1% Triton-X 100 (TX) for 1 min, (2) 10 µM calcium ionophore (CaI) for 20 min, (3) freezing and thawing (FT) without any cryoprotectant, or (4) no treatment (control). These sperm treatment groups then either did or did not receive additional sperm treatment with 5 mM dithiothreitol (DTT) for 20 min. Acrosomal integrity (Experiment 1) and DNA fragmentation (Experiment 2) were evaluated in the sperm before ICSI. In Experiment 3, oocytes matured in vitro were subjected to ICSI using pretreated sperm as described above and then were cultured either with or without activation. The TX- and CaI-treated sperm caused an increase in the number of acrosome-loss sperm, whereas the FT treatment and control increased the proportion of acrosome-reacted sperm (P<0.05). The DNA fragmentation did not differ among treatments (P>0.05). At 18 h post-ICSI, pronucleus (PN) formation was found only in activated oocytes. The majority of the activated ICSI oocytes contained intact sperm heads. Normal fertilization was observed in the CaI and FT treatment groups and control group when sperm were treated with DTT before ICSI. In conclusion, DTT treatment of sperm with reacted acrosomes before ICSI together with activation of the ICSI oocytes is important for successful male pronucleus formation.     

Reproductive consequences of an X-autosome translocation in a swine herd.

A survey was conducted on the chromosome makeup and breeding data of pigs housed at the Arkell Research Station, University of Guelph, to determine the reproductive impact of a reciprocal translocation previously identified as t(Xp+;14q-). Blood samples were cultured and chromosome spreads were examined to identify carriers in the herd. Gonadal features of carrier boars and piglets and their age-matched normal counterparts were studied, and the reproductive history of carrier sows, including the number of breedings required for conception, mean litter size, prevalence of still births and malformations, and sex distribution among the piglets, was compared with that of normal (noncarrier) sows. Our observations on testicular histology confirmed that X-autosome translocation-carrier boars are sterile, and the analysis of reproductive data showed that the most striking effects of t(Xp+;14q-) on sows are the 50% increase in the number of breedings required for conception and the over 25% reduction in litter size compared with that of normal sows. The reproductive impact of this and similar translocations on the herd and on the swine industry in general is discussed.     

Production of porcine aminopeptidase N (pAPN) site‐specific edited pigs

Porcine viral diarrhea is an acute and highly contagious enteric disease in pigs which causes huge economic losses in pig industry worldwide. Transmissible gastroenteritis virus (TGEV) is main pathogens responsible for piglets viral diarrhea. Knockout the host cellular surface receptor for TGEV may be an effective way to accelerate the breeding of resistant pigs. In this study, we applied site‐specific editing pAPN which is effective in swine testis (ST) cells. Site‐specific editing of pAPN reduced TGEV proliferation in ST cells by 96%–99% at different time periods post‐infection. Next, the site‐specific editing of pAPN porcine fetal fibroblasts were produced, and then the cell colonies were used as donor cells to generate the site‐specific editing of pAPN pigs. Our research findings will not only offer a more thorough understanding of the pathogenesis of piglet diarrhea and lay the foundation for breeding TGEV‐resistant piglets, but also understanding the molecular mechanisms involved in coronaviral infections.     

仔猪脾虚状态下单剂量口服左旋氧氟沙星的药动学研究

10头健康仔猪随机均分为健康组、脾虚组 ,按 2 0mg/kg的剂量进行内服左旋氧氟沙星的药动学研究。高效液相色谱法测定血浆中药物浓度 ,3P97药代动力学程序处理药时数据。健康组和脾虚组药动学数据适合一级吸收一室模型。健康组主要药动学数据为 :吸收半衰期 (t1 / 2ka)(0 42± 0 0 8)h ,消除半衰期 (t1 / 2ke) (7 62± 0 38)h ,达峰时间 (tmax) (1 85± 0 2 5)h ,达峰浓度 (Cmax) (6 99± 0 92 )mg/L ,药时曲线下面积 (AUC) (90 7± 1 0 0 7)mg·L- 1 ·h ,表观分布容积 (V/ F(s) ) (2 45± 0 2 8)L·kg,平均滞留时间 (MRT) (1 1 92± 0 94)h。脾虚组 :t1 / 2ka(1 1 7± 0 38)h ,t1 / 2ke (9 0 2± 1 1 8)h ,tmax (3 93± 1 0 5)h ,Cmax (4 2 8± 1 45)mg/L ,AUC (72 2 1± 1 6 0 7)mg·L- 1 ·h ,V/ F(s) (3 95±1 2 8)L·kg,MRT (1 3 74± 1 2 1 )h。结果表明 :仔猪脾虚状态下明显影响左旋氧氟沙星内服给药的药动学特征     

Full‐Term Development of Rabbit Embryos Produced by ICSI with Sperm Frozen in Liquid Nitrogen without Cryoprotectants

The aim of the present study was to establish the technology of intracytoplasmic sperm injection (ICSI) in rabbit by using the sperm frozen without cryoprotectants. Observation under an electron microscope revealed that the rabbit spermatozoa frozen without cryoprotectants had severe damage especially in the plasma membrane and junction between head and tail. However, after being injected into the oocytes, the sperm frozen without cryoprotectants retained the capability of supporting the cleavage and development of the ICSI oocytes, with no significant difference from that of fresh sperm, although the development of ICSI embryos derived from either frozen sperm or fresh sperm is much lower than that of in vivo‐fertilized zygotes. When additional artificial activation was applied following ICSI, the rates of cleavage and blastocyst formation of ICSI oocytes were significantly increased when compared with the oocytes without additional activation. Yet, the cell numbers in blastocysts were not significantly different between the activation and non‐activation group. After embryo transfer, four offspring were obtained from the oocytes microinjected with the sperm frozen without cryoprotectants. The technology established by this study may facilitate exploring the ICSI‐based transgenic method in rabbit and broaden the application of ICSI technique in related field.     

胰岛素和酶解配方乳对初生仔猪胃肠道生长发育影响的研究

为研究胰岛素和酶解配方乳是否促进初生仔猪胃肠道的生长发育 ,本试验比较了饲喂配方乳、配方乳补加胰岛素(60mIU/ml)或酶解(胰蛋白酶和糜蛋白酶)配方乳3天后仔猪胃肠的重量 ,肠道长度 ,肠粘膜DNA、RNA和蛋白质含量 ,血浆中皮质醇、胰岛素和胃泌素的水平。饲喂配方乳补加胰岛素或酶解配方乳的仔猪与饲喂配方乳的仔猪相比 ,胃、小肠、结肠的重量 ,小肠和结肠的长度 ,小肠粘膜DNA、RNA含量和结肠粘膜DNA、RNA、蛋白质含量均无显著变化(P>0.05) ;血浆中皮质醇、胰岛素水平也无显著差异(P>0.05)。但饲喂配方乳补加胰岛素的仔猪小肠粘膜尤其是回肠后段粘膜的重量(P<0.05)和蛋白质含量(P<0.01)显著高于饲喂配方乳的仔猪 ;饲喂酶解配方乳仔猪血浆的胃泌素水平均显著(P<0.01)高于饲喂配方乳的仔猪 ,酶解配方乳中可能含有刺激初生仔猪胃泌素释放的物质     

Comparisons of blood biochemical parameters,digestive enzyme activities and volatile fatty acid profile between Meishan and Yorkshire piglets

This study was conducted to compare physiological characteristics between Meishan and Yorkshire piglets in their early lives. Six healthy purebred Meishan sows and Yorkshire sows with close farrowing dates were used in this research. The piglets sucked their respective sow's milk for 14 days, then they were slaughtered to collect samples of blood, pancreas, contents of stomach, jejunum, cecum, colon as well as feces for analysis of blood biochemical parameters, digestive enzymes, and volatile fatty acid(VFA). The results showed that Yorkshire piglets had higher concentrations of high-density lipoprotein cholesterol(HDL-C) and total cholesterol(TC)(P 0.05). Gastric lipase activity was higher in Meishan piglets but Yorkshire piglets had higher lactase activity(P 0.05). The total VFA together with acetate and propionate in cecum and colon were higher in Meishan piglets than in Yorkshire piglets(P 0.05),but acetate in jejunum and ratio of acetate to propionate in colon were lower in Meishan piglets than in Yorkshire piglets(P 0.05). In conclusion, in early suckling period, significant differences exist in host metabolism and intestinal microbial metabolism between Meishan and Yorkshire piglets.     

ICSI受精卵胞质注射生产转基因猪胚胎的初步研究

试验旨在探讨单精子胞浆内注射（intracytoplasmic sperm injection,ICSI）法生产猪体外受精卵和应用猪ICSI受精卵进行胞质注射生产转基因胚胎的可行性。首先对比了猪体外受精（in vitro fertilization,IVF）受精卵与ICSI受精卵的胚胎发育效率;然后观察了猪ICSI受精卵的双原核形成时间及效率,对精子注射到胞质后6~18 h分6个时间段进行地衣红染色,对比精子进入卵胞质后的状态及原核形成;最后对猪IVF受精卵受精后8~10 h及ICSI受精卵受精后12~14 h进行EGFP-N1质粒（20 ng/μL）胞质注射,观察胚胎发育效率及转基因效率。结果表明,ICSI受精卵的胚胎发育率（卵裂率89.4%和67.9%、囊胚率36.5%和16.1%）显著优于IVF组（P<0.05）,适合用于猪的体外受精卵试验;猪ICSI受精卵双原核在精子注射到卵胞质后12~14 h形成,双原核形成率为54.90%,显著高于其余5个试验组（P<0.05）;ICSI受精卵胞质注射组胚胎卵裂率（86.2%和66.3%）、囊胚率（30.0%和13.6%）及转基因效率（18.5%和0）均显著高于IVF受精卵胞质注射试验组（P<0.05）。本试验结果为采用ICSI受精卵进行胞质注射生产转基因猪的研究奠定了基础。     

单精注射法生产转基因小鼠的研究

精子胞质内显微受精技术（ICSI）作为辅助受精的一种手段,将体外受精研究和胚胎的显微操作技术结合起来,比以往对精子质量的要求大大降低,使其无论在畜牧业生产实践还是在哺乳动物的生殖生理基础研究中都有着十分重要的意义。本研究用小鼠精子及小鼠精子与GFP基因孵育后对小鼠卵母细胞进行ICSI,获得子代鼠。提取鼠尾基因组DNA,应用PCR、Southern blot进行整合检测。在发育至成年的11只小鼠中经PCR和Southernblot检测到3只阳性（27.3%）。结果表明,利用ICSI技术可以高效地生产转基因小鼠。     

Delay in Cleavage of Porcine Embryos after Intracytoplasmic Sperm Injection (ICSI) Shows Poorer Embryonic Development

In pigs, the embryonic developmental ability after intracytoplasmic sperm injection (ICSI) is inferior to that resulting from in vitro fertilization (IVF). We evaluated the timing of cell division up to blastocyst formation on embryonic development after ICSI using either whole sperm (w-ICSI) or the sperm head alone (h-ICSI) and IVF as a control. At 10 h after ICSI or IVF, we selected only zygotes, and each of the zygotes/embryos was evaluated for cleavage every 24 h until 168 h. We then observed a delay in the 1st and 2nd cleavages of h-ICSI embryos and also in blastocoele formation by w-ICSI embryos in comparison with IVF embryos. The rate of blastocyst formation and the quality of blastocysts in both ICSI groups were inferior to those in the IVF group. In conclusion, the delay in cleavage of porcine ICSI embryos shows poorer embryonic development.     

饲粮补充精氨酸对低出生重哺乳仔猪肝脏氧化还原状态和线粒体功能的影响

本试验通过研究精氨酸(Arg)对低出生重(LBW)哺乳仔猪机体氧化还原平衡状态和线粒体功能的影响,探讨Arg改善LBW哺乳仔猪生长发育的可能机制。试验选取体况接近、产期一致和胎次相近的初产母猪所产仔猪,4日龄时,选取20头LBW[体重(1.16±0.08)kg]和10头正常出生重(NBW)[体重(2.07±0.10)kg]仔猪,按体重相近、公母比例一致的原则分为NBW组(饲喂基础饲粮)、LBW组(饲喂基础饲粮)和LBW+Arg组(基础饲粮补充1%Arg)3个组,每组10个重复,每个重复1头猪,人工乳饲养21 d。在第22天,屠宰并收集所有试验猪的血清与肝脏样品,检测生长性能、氧化还原状态与线粒体功能指标。结果表明:1)与NBW仔猪相比,LBW仔猪末重、平均日增重(ADG)和平均日干物质摄入量(ADMI)显著降低(P<0.05),肝脏过氧化氢酶(CAT)活性和ATP含量显著下降(P<0.05),肝脏环氧化酶(COX)ⅠmRNA表达量显著下调(P<0.05),肝脏视神经萎缩症蛋白1(OPA1)mRNA表达量有下调的趋势(P=0.089);2)饲粮补充Arg显著提高LBW仔猪末重、ADG和ADMI(P<0.05),显著提高血清CAT活性和肝脏CAT、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPx)活性(P<0.05),显著提高肝脏ATP含量(P<0.05),显著上调肝脏GPx1和线粒体融合蛋白1(Mfn1)mRNA表达量(P<0.05),并且有上调肝脏CAT(P=0.056)、COXⅣ(P=0.063)和OPA1(P=0.087)mRNA表达量的趋势。以上研究表明,LBW仔猪肝脏抗氧化能力下降,线粒体功能受阻,生长发育受到抑制;而饲粮补充1%Arg显著提高LBW仔猪肝脏抗氧化能力,改善线粒体功能,提高LBW仔猪生长性能。     

Impairment of the Peripheral Lymphoid Compartment in Iron‐deficient Piglets

The aim of this study was to investigate the effect of neonatal iron deficiency on immune functions in young piglets. While control piglets were not given any iron preparation until the age of 21 days, another group of piglets was given 200 mg of Fe³⁺‐dextran i.m. on day 3. Red blood cell parameters in the former, iron‐deficient group were characteristic of hypochromic anaemia. In addition, the total leucocyte count (P < 0.01), relative and absolute neutrophil count (P < 0.01) and absolute lymphocyte count (P < 0.05) in peripheral blood were found significantly lower in iron‐deficient piglets than in their iron‐supplemented counterparts. Lymphocyte activity as measured by in vitro lymphocyte transformation test was impaired in iron‐deficient piglets. A statistically significant decrease in circulating B‐lymphocyte numbers was found in non‐supplemented animals. Iron deficiency apparently negatively influenced the immunocompetence in piglets.     

Improved embryo development in Japanese black cattle by in vitro fertilization using ovum pick-up plus intracytoplasmic sperm injection with dithiothreitol

The purpose of this study was to determine whether dithiothreitol (DTT) treatment of sperm and ethanol activation improve embryo production by intracytoplasmic sperm injection (ICSI). Further, we compared ICSI with standard in vitro fertilization (IVF) in oocytes obtained from cattle. We demonstrated that DTT reduced the disulfide bond in the bovine sperm head. Using oocytes obtained from a slaughterhouse, ICSI-DTT treatment without ethanol showed the highest rate of blastocyst formation. We applied these results to fertilization using ovum pick-up (OPU). Eleven Japanese black cattle served as donors for OPU plus standard IVF (OPU-IVF). Of them, four donors with low embryo development rates were selected to determine whether embryo development was enhanced by OPU plus ICSI (OPU-ICSI). We assessed effects on embryo development following IVF and ICSI in oocytes obtained using OPU. Blastocyst rates were significantly higher for OPU-ICSI than for OPU-IVF. Our results suggest that OPU-ICSI improves the blastocyst development rate in donors with low embryo production compared with the standard OPU-IVF.     

Impact of RYR1 genotype of Piétrain boars on litter traits of Czech Large White × Czech Landrace crossbred sows

Summary Piétrain boars of different ryanodine receptor (RYR1) genotypes (NN, Nn and nn, three boars each) were mated with approximately 10 Czech Large White × Czech Landrace sows (genotype NN) each to produce one litter per sow. The progeny of nn boars had a significantly higher individual weaning weight (7.31 kg versus 6.86 kg) and average daily gain from birth to weaning (252 g/day versus 240 g/day) than the progeny of NN boars. Furthermore, piglets from nn boars differed statistically significant also from piglets of boars with the Nn genotype for these two traits. The litters of the NN boars were greater by 0.5 piglets than the litters of the nn boars for the total number of piglets born, piglets born alive and piglets weaned, but the differences were not significant. The Nn genotype showed for all litter size traits and the number of stillborn piglets the best values. The difference between the genotypes Nn and nn was statistically significant at the 0.05 level for the number of piglets born alive and the number of piglets weaned.     

Stillbirth in the pig in relation to genetic merit for farrowing survival

The objectives of this study were to analyze the incidence of different categories of stillborn piglets in relation to genetic merit for farrowing survival of sows and litters and to analyze relationships of total number of piglets born per litter, average BW of the litter, and within-litter variation in BW with genetic merit for farrowing survival of sows and litters. Records of 336 purebred litters, produced by 307 first-to eighth-parity sows, were collected on a nucleus farm in Brouennes, France. Breeding values for farrowing survival were estimated for sows (EBVfs_maternal) and litters (EBVfs_direct) using a large data set from which information obtained in the current study was excluded. For each litter, BW, number of stillborn piglets (classified as nonfresh stillborn, prepartum stillborn, intrapartum stillborn, and postpartum stillborn), and number of live-born piglets were recorded. Birth weights of stillborn piglets were lower than BW of live-born piglets (P < 0.0001), except for prepartum stillbirths. The total number of stillborn piglets per litter and the number of stillborn piglets in each category decreased with increasing EBVfs_maternal (P < 0.01). An increase in EBVfs_direct was also associated with a decrease in the total number of stillborn piglets per litter (P < 0.01). This decrease was due to a decrease in the number of nonfresh, prepartum, and postpartum stillborn piglets but not to a decrease in the number of intrapartum stillborn piglets. Probabilities of stillbirth in relation to EBVfs_maternal were higher than probabilities of stillbirth in relation to EBVfs_direct. Total number of piglets born decreased with increasing EBVfs_direct (P = 0.0003), but was not related to EBVfs_maternal. Average BW of the litter (P < 0.0001) and within-litter variation in BW (P = 0.05) decreased with increasing EBVfs_maternal but were not related to EBVfs_direct. Selection for the maternal genetic component of farrowing survival seems a better strategy than selection for the direct genetic component. Selection for the maternal genetic component of farrowing survival reduces stillbirth in all categories and does not affect litter size.     

增食欲素受体2在哺乳仔猪空肠中的表达规律

采食状况是影响猪早期生长发育的一个主要因素。增食欲素在调节食欲上具有重要作用,但其发挥作用的前提是必须与其受体结合。为研究增食欲素受体2(HCRTR2)在哺乳仔猪肠道是否表达及其表达规律,本研究采用实时荧光定量PCR方法,检测其在0、3、8、14、21日龄大约克仔猪空肠中的表达。结果表明:HCRTR2能在哺乳仔猪空肠中表达,与0日龄相比,HCRTR2在3、8、14、21日龄表达水平均明显上升,其中在3日龄的表达量达到最高水平,而后逐渐下降趋于平稳状态,增加幅度分别为5.2、3.5、2.9、2.7倍。这表明HCRTR2在哺乳仔猪空肠中有表达,且在3日龄达到高峰。据此可以推测,该基因在仔猪肠道生长发育过程中具有调节作用。     

Development and evaluation of a nested-PCR assay for <Emphasis Type="Italic">Senecavirus A</Emphasis> diagnosis

Senecavirus A (SVA) has been associated with vesicular disease in weaned and adult pigs and with high mortality of newborn piglets. This study aimed to establish a nested-PCR assay for the routine diagnosis of SVA infection. Tissue samples (n = 177) were collected from 37 piglets of 18 pig farms located in four different Brazilian states. For the nested-PCR, a primer set was defined to amplify an internal VP1 fragment of 316 bp of SVA genome. Of the 37 piglets, 15 (40.5%) and 23 (62.2%) were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. The SVA RNA was detected in 61/177 (34.5%) samples with the RT-PCR, while the nested-PCR assay showed 84/177 (47.5%) samples with the virus (p < 0.05). According to the herds, 11 (61.1%) and 16 (88.9%) of the 18 pig herds were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. Nucleotide sequencing analysis revealed similarities of 98.7–100% among SVA Brazilian strains and of 86.6–98% with SVA strains from other countries. The nested-PCR assay in this study was suitable to recover the SVA RNA in biological specimens, piglets, and/or herds that were considered as negative in the RT-PCR assay, and is proposed for the routine investigation of the SVA infection in piglets, especially when other techniques are not available or when a great number of samples has to be examined.