大白猪BF基因多态性与繁殖性状及胎盘效率关联研究

文章以BF基因为产仔数的候选基因, 运用PCR-RFLP方法对大白猪BF基因内含子1序列进行分析, 发现内含子1第79 bp处发生了C→T突变, 命名为BF-intron 1-C79T。所扩增PCR产物经SmaⅠ酶切后, 可分出3种基因型, 分别为CC、CT和TT。经χ²适合性检验, 大白猪群体在该位点达到了Hardy-Weinberg平衡状态。将不同基因型与总产仔数(TNB)、产活仔数(NBA)、初生重(BW)和胎盘效率(PE)进行关联分析, 结果发现, 初产母猪在该位点上, CC基因型比CT基因型个体的TNB和NBA均多3.10头, 但差异不显著(P>0.05); 在BW和PE上, CC基因型均高于CT基因型, 差异不显著(P>0.05)。经产母猪在该位点上, CC基因型比TT基因型个体的TNB和NBA分别多3.45头和3.92头, PE高23.80%, 均达到显著水平; 但CT基因型个体与CC和TT个体之间的TNB 、NBA和PE差异不显著(P>0.05)。因此, BF-intron 1-C79T位点可作为繁殖性状及胎盘效率的潜在分子育种标记, 具有很大的研究价值。     

母猪生殖器官大小和产仔数的分子遗传基础

采用单核苷酸多态分析技术（SNP）分析母猪3个生殖激素受体基因（ESR、PRLR和FSHR）的变异,屠宰103头母猪并测定其生殖器官大小;统计母猪的产仔数;利用SAS或SPSS分析软件分析基因变异与母猪的生殖器官大小,产仔数多少的连锁关系,以探讨母猪生殖器官大小和产仔数多少的分子遗传基础,结果表明,如母猪携带的基因型为位点,ESR的BB型,位点FSHRB的BB型,位点ESRB的AA型,位点PRLR的AA型,则母猪的生殖器官较大,产仔数也较多;在位点ESRB或位点PRLR中,带有AA基因型母猪不仅产仔数显著地高于AB、BB型,而且生殖器官也显著大于AB、BB型;在位点ESR和FSHRB中,带有BB基因型母猪的生殖器官,产仔数显著高于带有AB或AA型母猪。     

Polymorphisms in follicle stimulation hormone receptor, inhibin alpha, inhibin bata A, and prolactin genes, and their association with sperm quality in Chinese Holstein bulls

Candidate genes follicle stimulation hormone receptor (FSHR), inhibin alpha (INHA), inhibin bata A (INHBA) and prolactin (PRL) were investigated for their association with sperm quality traits of semen volume per ejaculate (VOL), sperm concentration (SCON), motility (MOT), sperm motility in frozen semen (FMOT), acrosome integrity rate (AIR) and abnormal sperm rate (ASR) in a total of 123 normal mature Holstein bulls. Three reported single nucleotide polymorphisms (SNPs) of FSHR A-234500T (rs43676359), IHNA A192G (rs41257116), and IHNBA C7639T (rs43408735), and 3 novel SNPs (G7550A, C7661T, and T8370C) in exons 4 and 5 of bovine PRL gene (NC 007324) were analyzed. Analysis of variance revealed that FSHR A-234500T and INHBA C7639T polymorphisms significantly associated with VOL (P<0.05) and SCON (P<0.05), and the polymorphism of INHBA C7639T also had significant effects on MOT (P<0.05). Furthermore, the INHA A192G polymorphism significantly associated with AIR (P<0.05). No significant differences were found between the polymorphisms of PRL gene and sperm quality traits.     

Genetic variation and association of prostaglandin F2alpha receptor (PTGFR) gene with sow maternal behaviors in a White Duroc x Erhualian resource population

Maternal behaviors of sows around parturition are important for survival of newborn offspring. Failure to establish normal maternal bonds such as maternal infanticide and crushing often occurs in some individuals. It causes both significant economic losses to the pig industry and severe problems of piglet welfare. Prostaglandin F2-alpha not only can stimulate the nest-building behavior of sows before parturition but also plays an important role in reproductive process and maternal behavior through protein FP encoded by the prostaglandin F receptor gene (PTGFR) as its receptor. In this study, genetic variation and association study of PTGFR gene with nest-building behavior, maternal infanticide, and crushing behavior was carried out in a White Duroc x Erhualian resource population. As a result, five synonymous mutations were identified on exon 1 and exon 2. Exon 1 g .250 A>G, Exon 1 g.619 G>A and Exon 2 g.483 T>C were chosen for genotyping in individuals of F0, F1 and 289 F2 sows. Family-based transmission disequilibrium test (TDT) demonstrated that there were no significant associations of 3 SNPs and haplotypes of PTGFR gene with sow nest-building, maternal infanticide and crushing behavior (P > 0.05). Therefore, it can be concluded that PTGFR gene is not the causative candidate gene for sow maternal behaviors.     

猪PRLR和RBP4基因多态性与产仔性能的关系

采用PCR-RFLP方法, 对莱芜黑猪、鲁莱黑猪、里岔黑猪、鲁烟白猪、新沂蒙黑猪5个山东地方/培育猪种和大约克夏、长白、杜洛克3个引进猪种共8个猪种323头繁殖母猪进行PRLR和RBP4基因的多态性检测, 并采用最小二乘法分析其对产仔数影响的遗传效应。结果表明: 两个基因位点在8个猪种的测定群体中均存在多态性, 但山东地方/培育猪种与引进猪种间在基因型频率上存在较大差异。PRLR和RBP4基因对产仔数性状有显著影响(P<0.05), AA均为优良基因型。对于PRLR基因, 山东地方/培育猪种内AA基因型母猪的总产仔数和活产仔数比BB基因型母猪平均多产1.03头和0.89头, 引进猪种中AA基因型母猪比BB基因型母猪平均多产分别为1.26头和1.11头。对于RBP4基因, 山东地方/培育猪种内AA基因型母猪的总产仔数和活产仔数比BB基因型母猪平均多产0.59头和0.51头, 引进猪种中AA基因型母猪比BB基因型母猪平均多产分别为0.72头和0.64头     

Sequencing and gene expression of the porcine ITIH SSC13 cluster and its effect on litter size in an Iberian × Meishan F2 population

The aim of the present study was to identify polymorphisms and to analyze endometrial gene expression of the porcine SSC13 ITIH cluster that could explain differences in prolificacy of 255 F(2) sows derived from an Iberian (Ib)×Meishan (Me) intercross in which QTL for the number of piglets born alive (NBA) and total number of piglets born (TNB) were previously detected on this chromosome. Sequencing of ITIH-1, -3, and -4 mRNAs was done and several polymorphisms segregating within the Ib×Me population were found in all three genes. Significant associations with NBA were found for two SNPs from ITIH-1, four from ITIH-3, and four SNPs from ITIH-4 (p<0.05). Haplotypes for the significant SNPs were calculated by segregation analysis and a marker assisted association test indicated that the alleles coming from the Meishan breed had a favorable effect on NBA for all three genes. Interestingly, some of the significant SNPs were located within the von Willebrand domain of the ITIH proteins, the binding site of molecules essential for the synthesis of the extracellular matrix during cumulus expansion. Gene expression analyses also revealed differences in the expression level of the ITIH-3 gene regarding the prolificacy performance (high or low) and the uterus sample (apical or basal).     

Association of BF,RBP4, and ESR2 Genotypes with Litter Size in an Autochthonous Pig Population

The aim of the present study was to determine any potential association of the BF, RBP4, and ESR2 genes with reproduction traits in an autochthonous Greek pig population. The PCR-RFLP methodology was implemented for genotyping purposes of the examined genes. No deviation from the Hardy-Weinberg equilibrium was observed for the examined loci, while the B allele noted to be the more frequent in all analyzed genes. In addition, sows with the AA genotype of BF gene found to produce significantly lower numbers of the total born piglets (TNB) and number of piglets born alive (TNA), while the respective BB genotype significantly exceeded in TNB and NBA traits compared to the other two genotypes (P?Abbreviations: TNB: Total number of born piglets; NBA: Number of piglets born alive     

Effect of polymorphism in the leukemia inhibitory factor gene on litter size in Large White pigs

DNA polymorphism of the porcine leukemia inhibitory factory (LIF) was investigated and used to study the effects on litter size in Large White pigs. A total of 2,167 litter records from 420 sows genotyped at two SNP loci (LIF1 and LIF2) within LIF gene were analyzed to determine whether LIF influenced total number born (TNB) and number born alive (NBA). The results indicated that B allele at LIF1 locus and A allele at LIF2 locus seem to have advantageous effects on litter size. However, the combined analyzed results demonstrated that genotype AAAA, ABBB, and BBBB are better than genotype AAAB, AABB, and ABAB for TNB and NBA in either third to eighth parity or all parities. In all parities, the sows with AAAA genotype had an advantage of 1.76 piglets (P < 0.001) for TNB and 1.44 piglets (P < 0.01) for NBA per litter over the AAAB sows, respectively. The results in this study demonstrated that LIF gene was significantly associated with litter size in pigs. H. C. Lin and G. F. Liu contributed equally to this work.     

Characterization of swine adiponectin and adiponectin receptor polymorphisms and their association with reproductive traits

In this study, polymorphisms in genes encoding porcine adiponectin (ADIPOQ) and its receptors (ADIPOR1 and ADIPOR2) were evaluated for associations with reproductive traits in a Landrace sow population. Sixteen SNPs were identified, and among these, associations were found between reproductive traits and five SNPs. Heterozygous multiparous females for SNP ADIPOQEF601160:c.178G>A had fewer stillborn piglets (P < 0.05) and shorter weaning-to-oestrus intervals (P < 0.05). Multiparous females bearing the mutant allele for SNP ADIPOQEF601160:c.*1094_1095insC gave birth to fewer stillborn piglets (P < 0.05). In addition, selection for the ADIPOQ [A;C] haplotype is expected to result in multiparous sows having the lowest number of stillborn piglets and shorter weaning-to-oestrus intervals. In second-parity sows, the polymorphism in ADIPOR1 (AY856513:c.*129A>C) showed significant associations with live-born (P < 0.01) and stillborn (P < 0.05) piglets. In multiparous sows, a significant association was observed for an ADIPOR2 polymorphism (AY856514:c.*112G>A), with the c.*112GA genotype associated with shorter weaning-to-oestrus intervals (P < 0.01). Haplotype analyses of ADIPOR2 SNPs revealed that selection in favour of the [A;C] haplotype and against the [G;G] haplotype may result in sows having an increased number of live-born piglets and shorter weaning-to-oestrus intervals. We have therefore described specific SNPs and haplotypes that are associated with large litter size, fewer stillborn and mummified piglets and shorter weaning-to-oestrus intervals. Selection for these SNPs and haplotypes is a strategy to improve reproductive success in pigs.     

中华鳖GHSR基因SNPs的筛选及生长性状的关联分析

为探究GHSR基因多态性对中华鳖(Pelodiscus sinensis)生长相关性状的影响,采用直接测序法在GHSR基因5'侧翼和3'侧翼上筛选SNPs位点,共检测到5个单核苷酸多态性位点:A335T、G397T、A527G、A13482C和T13526A。随机选取同批繁殖的1冬龄200只中华鳖用直接测序法进行SNPs位点的分型,并分析与生长性状的相关性。检测结果显示,所有SNP位点均符合Hardy-Weinberg平衡状态(p>0.05)。方差分析显示,A336T位点的AT、TT基因型的体重、背甲长、背甲宽和裙边宽4项生长数据均显著高于AA基因型。A13482C位点的AC基因型的体重、背甲长、背甲宽和裙边宽4项数据均显著高于AA基因型(p<0.05)。研究表明,本实验在GHSR基因上获得的这些SNP位点可能影响着中华鳖的生长性状或与之紧密连锁,可为中华鳖分子辅助育种提供助力与参考。     

Reproductive performance of purebred landrace and Yorkshire sows in Thailand with special reference to seasonal influence and parity number

The purpose of this study was to analyze reproductive performance in purebred Landrace and Yorkshire sows with special reference to seasonal influence and parity number, under tropical conditions where day length is almost constant throughout the year. Data from three purebred sow herds in Thailand during the period from 1993 to 1996 were analyzed. The two breeds were present in all three herds. The analysis comprised records of 3848 Landrace sow litters and 2033 Yorkshire sow litters. The statistical models included the fixed effects of month, year, parity, breed of the sow, herd, and two-way interactions of breed-parity, breed-herd, breed-month, breed-year, parity-month, month-herd, year-herd and month-year. The random effect of sow within breed was included in all models. Analysis of covariance was performed to analyze the effect of temperature, humidity and heat index on number of total born per litter (NTB), weaning to first service interval (WSI) and farrowing rate (FR). Landrace sows had significantly higher NTB (0.6 piglets), number of live born per litter (0.5 piglets), and average birth weight (0.13 kg) than Yorkshire sows (P<0.001). Farrowing rate was 3.9% higher in Landrace sows than in Yorkshire sows (P<0.01). However, Yorkshire sows had significantly shorter WSI (P<0.001) and significantly higher proportion of sows served within 7 days after weaning (P<0.01) than Landrace sows. No breed differences were found in number of stillborn per litter and weaning to conception interval. Parity had significant effect on all reproductive parameters analyzed. Number of total born and live born per litter was significantly lower for sows farrowing during the rainy season than in other seasons. Farrowing rate was low for sows mated during the hot and rainy season. Weaning to service interval and WSI7 were prolonged for sows weaned during the hot and rainy season. Reproductive performance was significantly unfavorably influenced by elevated temperature and heat index after mating (NTB and FR) or during lactation (WSI).     

Genotyping by sequencing reveals a new locus for pig teat number

Teat number is an extremely valuable trait for sow reproduction performance and piglet survival. Here, we used genotyping‐by‐sequencing and a general liner model to carry out genome‐wide analysis of sow total teat number in an Erhualian population. The results indicated that eight SNPs on chromosomes 4, 5, 9 and 10 were significant genome wide (Bonferroni method, P < 2.85E‐7) for sow total teat number. Validation analyses were performed in 298 Erhualian and 904 Large White sows using these significant SNPs and the general liner model procedure in sas . Finally, only the SNP on chromosome 5 was found to be significantly associated with sow teat number in both populations. The GG genotype individuals had 2.23 and 0.82 more teat numbers respectively than did the AA genotype individuals in these two populations (P < 0.05). According to the expression and annotation analyses, we inferred the presence of a gene or lincRNA that could affect teat number by regulating other genes and ultimately affecting the mammogenesis of pigs. Further studies using methods such as Cas9 editing and gene silencing analysis are necessary for additional function analysis.     

Polymorphism of the pig 17beta-hydroxysteroid dehydrogenase type1 (HSD17B1) gene and its association with reproductive traits

17beta-Hydroxysteroid dehydrogenase type 1 (HSD17B1) is a key enzyme of 17beta-estradiol biosynthesis, which might play an important role in follicular development of the ovary. In this study, we isolated the complete coding sequence of porcine HSD17B1 gene and its unique intron sequences of porcine HSD17B1 gene, identified a single nucleotide polymorphism (SNP: A/C) in intron 4, and developed a PCR-MvaI-RFLP genotyping assay. Association of the SNP and litter size was assessed in two populations (purebred Large White and a experimental synthetic Line (DIV) sows). Statistical analysis demonstrated that, in the first parity, AC animals in experimental synthetic Line (DIV) sows had 0.52 more piglets born compared to the CC animals (P<0.05). In the all parities, pigs with the AA genotype had an additional 1.11 and 0.96 piglets born alive compared to the CC animals (P<0.05) in both experimental synthetic Line (DIV) and purebred Large White, respectively. Experimental synthetic Line (DIV) sows inheriting the AC genotype had additional 0.84 piglets born alive compared to the CC animals (P<0.01) in all parities. In addition, significant additive effect of -0.55+/-0.24 piglets/litter and -0.48+/-0.22 piglets/litter on piglet born alive was detected in both experimental synthetic Line (DIV) sows and purebred Large White lines (P<0.05), respectively. Therefore, HSD17B1 gene was significantly associated with litter size in two populations and could be a useful molecular marker in selection for increasing litter size in pigs.     

Association of B3GNT5 Polymorphisms with Susceptibility to ETEC F4ab/ac in the White Duroc?×?Erhualian Intercross and 15 Outbred Pig Breeds

The B3GNT5 gene is a candidate for the F4ab/ac receptor conferring susceptibility to enterotoxigenic Escherichia coli (ETEC) F4ab/ac in pigs. In this study, we screened mutations in the complete coding region of the porcine B3GNT5 gene and identified four SNPs in the 3' untranslated regions. We genotyped the four SNPs across a large-scale White Duroc × Chinese Erhualian F2 resource population (total F2 = 755) and 292 purebred piglets representing 15 Chinese and Western breeds. We found that the g.1476G→A locus and haplotypes [A;T;G;T] and [A;G;G;T] had significant association with susceptibility to ETEC F4ac in the resource population. None of the B3GNT5 polymorphisms and haplotypes was associated with susceptibility to ETEC F4ab/ac in outbred piglets. This result, together with other reports, supports the conclusion that B3GNT5 is not the responsible gene encoding the ETEC F4ab/ac receptors.     

Use of meta-analysis to combine candidate gene association studies: application to study the relationship between the ESR PvuII polymorphism and sow litter size

This article investigates the application of meta-analysis on livestock candidate gene effects. The PvuII polymorphism of the ESR gene is used as an example. The association among ESR PvuII alleles with the number of piglets born alive and total born in the first (NBA1, TNB1) and later parities (NBA, TNB) is reviewed by conducting a meta-analysis of 15 published studies including 9329 sows. Under a fixed effects model, litter size values were significantly lower in the "AA" genotype groups when compared with "AB" and "BB" homozygotes. Under the random effects model, the results were similar although differences between "AA" and "AB" genotype groups were not clearly significant for NBA and TNB. Nevertheless, the most noticeable result was the high and significant heterogeneity estimated among studies. This heterogeneity could be assigned to error sampling, genotype by environment interaction, linkage or epistasis, as referred to in the literature, but also to the hypothesis of population admixture/stratification. It is concluded that meta-analysis can be considered as a helpful analytical tool to synthesise and discuss livestock candidate gene effects. The main difficulty found was the insufficient information on the standard errors of the estimated genotype effects in several publications. Consequently, the convenience of publishing the standard errors or the concrete P-values instead of the test significance level should be recommended to guarantee the quality of candidate gene effect meta-analyses.     

Breeding replacement gilts for organic pig herds

In this study, breeding structures and commercial sow lines were evaluated by economic and genetic simulation studies for their suitability to provide the Dutch organic pig sector with replacement gilts. Sow and litter performance from over 2000 crossbred sows from 2006 to 2007 were collected on 11 to 14 Dutch organic pig herds, respectively, and compared with conventional herds. Results showed that organic herds had lower farrowing rates (3.6% to 7.5%), more live born piglets per litter (0.4% to 1.2%) and higher preweaning mortality rates (7% to 13%) compared to conventional herds. These results were used to simulate economic performance of various combinations of breeding structures and sow lines under organic conditions, under the assumption of absence of genotype-environment interactions. Sow and litter performance data under organic conditions (total piglets born/litter, stillborn piglets/litter, mortality until weaning, lactation length, interval weaning-oestrus and sow culling rate) and the costprice calculation for the Dutch organic pig sector were used as input for the economic simulation studies. The expected genetic progress was simulated for three potential breeding structures of the organic sector: organic breeding herds producing F1 gilts (OrgBS), a flower breeding system (FlowerBS) and a two-line rotation breeding system (RotBS). In FlowerBS, an organic purebred sow line is bred, using on-farm gilt replacement. The OrgBS with a Yorkshire × Landrace cross had the highest margin per sow place (€779), followed by RotBS with Yorkshire × Landrace cross (€706) and FlowerBS with Yorkshire sow line (€677). In case that an organic purebred sow population of 5000 sows would be available, FlowerBS gave the highest genetic progress in terms of cost price reduction (€3.72/slaughter pig per generation), followed by RotBS and OrgBS (€3.60/slaughter pig per generation). For FlowerBS, additional costs will be involved for maintaining a dedicated breeding programme. In conclusion, OrgBS using conventional genetics is economically the most viable option for the organic pig sector. However, this structure has clear disadvantages in terms of risks with regard to disease transmission and market demand. FlowerBS using a dedicated purebred organic line will only be cost-effective if sow population size is sufficiently large. RotBS might be a viable alternative, especially in combination with artificial insemination (AI) boars that are ranked according to an organic selection index. Regardless of breeding structure, the Yorkshire sow line gave the highest prolificacy and the highest economic returns on organic herds.     

Effect of polymorphism in the peroxisome proliferator-activated receptor gamma gene on litter size of pigs

The association of polymorphisms in peroxisome proliferator-activated receptor γ (PPARγ) gene with litter size was studied in Large White and Landrace pig. Three SNP loci (P1, P2 and P7) on PPARγ₂ gene were determined by PCR–SSCP and the results showed that there were A → G mutations at 220 and 324 bp in 5′-regulator region and at 147 bp in exon 6, respectively. Allele frequencies were analysed in two breeds. Information on 2341 litter records from 564 sows was used to analyse the trait total number born (TNB) and number born alive (NBA). In Large White, TNB and NBA of genotype BB for P2 locus were the lowest, and the TNB and NBA of third and following parities and all parities were 0.74 and 0.51 piglets per litter less (P < 0.001) than those of the highest genotype AB, respectively, but for P1 and P7 locus the beneficial genotype AA were more 0.4–0.8 piglets per litter (P < 0.05) than the inferior genotype AB. In landrace, TNB and NBA of the first parity of genotype BB for P1 locus were 2.0 piglets per litter higher than AA (P < 0.05), but for all parities the TNB and NBA of genotype BB were 0.66 and 0.97 piglets per litter (P < 0.05) higher than AA, respectively. At P2 locus, the TNB and NBA of the second parity of genotype AA were obviously higher than those of AB (P < 0.05). And at P7 locus, the TNB and NBA of each parity of genotype AA were both about 2 piglets per litter more than those of BB (P < 0.05). The results indicated that PPARγ gene was significantly associated with litter size in pigs.     

The effect of a SNP in ESR gene on the reproductive performance traits in Polish sows

The aim of the experiment was to detect polymorphism in the ESR gene to determine associations between the genotype and litter size in Polish Large White and Landrace sows. Reproductive traits investigated were: total number of piglets born (TNB), number of piglets born alive (NBA) and number of piglets weaned (TW). The polymorphism in ESR gene was detected using the PCR-RFLP method, with specific primers and the restriction enzyme AvaI. Two different alleles of ESR gene were identified: alleles A (0.71) and B (0.29). The relationship between the ESR genotypes and TBN, NBA and NW were analyzed. The analysis showed in first parity sows statistically significant (P < 0.01) differences between sows carrying different ESR genotypes. The analysis of ESR gene showed that sows with BB genotype had the largest litter size compared to AB and BB sows, but the difference was statistically not significant.     

中华绒螯蟹MSTN基因SNPs多态性及与生长性状的关联分析

为研究中华绒螯蟹(Eriocheir sinensis)肌肉生长抑制素基因(myostatin, MSTN)的多态性及其与生长性状的相关性, 对中华绒螯蟹3个群体(育种群体、大赛群体、野生群体)共321个个体MSTN基因的多态性进行筛选, 发现该基因的第1外显子存在3个多态性SNP位点(S1: C714T; S2:G729A; S3:G753T), 均为处于Hardy-Weinberg平衡(P>0.05)的中、高度多态性位点。利用一般线性模型分析3个位点及其基因型组合与生长性状的相关性, 发现S1位点对中华绒螯蟹的体重和壳长等生长性状有显著影响(P≤0.05), 而其余2个位点与生长性状无显著关联性。结果表明S1位点的TT基因型对中华绒螯蟹的生长最为有利, 可作为分子标记辅助育种的候选标记。     

鸽黑素皮质素受体3、4(MC3R、MC4R)基因多态性与生长性状的相关分析

利用PCR-SSCP技术和DNA测序方法检测广东石岐肉鸽和哈尔滨地区灰色家鸽MC3R和MC4R基因部分编码区序列的单核苷酸多态性, 分析了MC3R基因T91G突变位点和MC4R基因A903G突变位点导致的基因型与两群体鸽生长和体组成性状的关系。结果表明, 这两个多态位点所导致的基因型对石岐肉鸽活重、屠体重、全净膛重均有显著影响(P<0.05); 另外, 利用这两个突变位点所产生的合并基因型在鸽群体中与生长和体组成性状作最小二乘分析, 结果表明, 两位点合并后的基因型对全净膛重影响显著(P<0.05)。多重比较结果表明, BBAA型全净膛重显著大于AABB型, BBAA型对于体重增长是有利基因型。