Identification of mutations of zona pellucida glycoprotein (ZP3) and its association with pig reproductive traits

Reproduction is a complex trait, controlled by genetic and environmental factors. Genetic improvement of this trait is important for animal breeders to improve the animal's production efficiency. Apart from genetic factors, animal production can be affected by environmental factors, i.e. the nursing ability of the sow, which is in turn affected directly by effective teat number (teats producing milk normally, TN) and number of piglets born alive (NBA). The objective of this study was to find new mutations, such as single nucleotide polymorphisms (SNPs) from the Zona Pellucida glycoprotein gene (ZP3) using Single Strand Chain Polymorphism (SSCP) and nucleotide sequencing and to investigate association between genetic variations and sow reproductive traits. We identified 13 new SNPs from exon 1, two new SNPs from intron 2, one SNP from intron 6 and a 18 bp (GCACGTGGTCCTCCTGG)‐deletion/insertion from intron 2 of the ZP3 gene. Five out of these mutations were selected to genotype in five different breeds (Small Meishan, Qingping, Duroc, Landrace and Large White) and association with reproductive traits in European breeds (Duroc, Landrace and Large White). The sows with genotype AA had more 1.11 piglets NBA than of the sows with genotype AB (p < 0.05) in the 18 bp deletion/insertion of intron 2, while non‐significant associations between the other mutations and reproductive traits (NBA and TN) were found.     

A substitution within erythropoietin receptor gene D1 domain associated with litter size in Beijing Black pig,Sus scrofa

Studies of uterine capacity and litter size in swine have suggested that erythropoietin receptor (EPOR) plays an important role in fetal survival through maturation of red blood cells. In this study, we screened the porcine EPOR gene for mutations and identified three single nucleotide polymorphisms (SNPs): two missense mutations and one synonymous mutation. We then genotyped 272 Beijing Black sows, Sus scrofa, and compared this data with litter sizes from a total of 1523 parities among the sows. The G allele of the nonsynonymous SNP, EPOR c.434A>G, was associated with greater litter size at both first parity (P < 0.05) and at later parities (P < 0.01). This SNP causes His92Arg adjacent to the fourth conserved cysteine residue in the mature protein and is in the D1 domain of the protein. Additionally, we determined the allele frequencies for this SNP among six Chinese indigenous pig breeds (Bamei, Erhualian, Laiwu Black, Mashen, Meishan and Min) and three Western commercial pig breeds (Duroc, Landrace and Large White). The c.434G allele was significantly more common among the more prolific Chinese breeds than the Western breeds, implying that EPOR c.434A>G could be a useful genetic marker to improve litter size in swine.     

禽肉色泽影响因素研究进展

本文对禽肉色泽及其影响因素包括内在因素(肌红蛋白含量、血红素的化学形态、pH)及人为因素(应激、营养因子、视觉缺陷)进行了综述。     

Association of a single nucleotide polymorphism in the 5' upstream region of the porcine myosin heavy chain 4 gene with meat quality traits in pigs

We identified a potential molecular marker associated with meat quality traits in the myosin heavy chain 4, MYH4 gene of Landrace pigs. Sequencing revealed a single nucleotide polymorphism (SNP; g.‐1398G>T) in the 5' upstream region of MYH4. It was significantly associated with the number of type IIa muscle fibers and water‐holding capacity based on filter‐paper fluid uptake. The GG genotype groups had a greater number of type IIa fibers and a larger area composed of type IIa fibers than the other genotype group (P = 0.004 and P = 0.061, respectively). Expression level of MYH4 gene in the genotype TT or GT was higher than in genotype of GG (P < 0.0001). The T allele may enhance expression level of MYH4 gene and then the portion of IIb type fiber in the muscle be increased by the T allelle. Therefore, we suggest that the g.‐1398G>T in the 5' upstream region of the porcine MYH4 may be used as a molecular marker for meat quality traits, although its functional effect is not defined yet.     

A retrospective analysis of allele frequency changes of major genes during 20 years of selection in the Italian Large White pig breed

In this study, we investigated whether a selection programme based on boar genetic evaluation obtained with a classical BLUP animal model can change allele frequencies in a pig population. All Italian Large White boars born from 1992 to 2012 with estimated breeding value reliability >0.85 (n = 200) were selected among all boars of this breed. Boars were genotyped with markers in major genes (IGF2 intron3‐g.3072G>A, MC4R p.D298N, VRTN PRE1 insertion, PRKAG3 p.I199V and FTO g.276T>G). Genotyping data were analysed grouping boars in eight classes according to their year of birth. To evaluate the influence of time on allele frequencies of the genotyped markers, multinomial logistic regression models were computed. Four of five polymorphic sites (IGF2, MC4R, VRTN and FTO) showed significant (p < 0.01) changes in allele frequencies over time due to a progressive and continuous increase of one allele (associated with higher lean meat content, higher average daily gain and favourable feed: gain ratio) and, consequently, decrease of the other one, following the directional selection of the selection programme of this pig breed. The retrospective analysis that was carried out in Italian Large White boars suggests that selection based on methodologies assuming the infinitesimal model is able to modify in a quite short period of time allele frequencies in major genes, increasing the frequency of alleles explaining a relevant (non‐infinitesimal) fraction of the overall genetic variability for production traits.     

宰前短期添加镁对PIC育肥猪肉色和pH值的影响

试验研究了宰前短期添加不同剂量镁对PIC育肥猪肉质的影响。试验以PIC育肥猪为研究对象,共分4个处理,每个处理4头。分别在限饲基础日粮基础上每日补饲0、2、4、6 g镁。结果表明:每头添加镁2 g/d有提高色素含量趋势(P>0.05),添加4 g/d可极显著提高肌肉色素含量7.41%(P<0.01),添加6 g/d显著提高肌肉色素含量(P<0.05);肉色评分随添加剂量的增加而提高,2 g/d可以显著提高肉色评分(P<0.05),4、6 g/d可极显著提高肉色评分(P<0.01);随镁添加量的增加,肌肉pH值显著提高(P<0.05),6 g/d添加组与对照组相比较差异极显著(P<0.01)。宰前5 d补镁可增加肉色,显著提高肌肉pH值,改善猪肉品质。     

Ob基因对松辽黑猪肉质和胴体性状的影响

以松辽黑猪为研究对象,分析Ob基因对其肉质和胴体性状的影响。测定30头松辽黑猪的9个肉质性状和6个胴体性状,用PCR-RFLP方法检测Ob基因型。结果显示,松辽黑猪TT基因型平均膘厚比CT基因型低,而肌内脂肪含量、瘦肉率则显著高于后者(P<0.05),其他肉质和胴体性状在Ob基因型间没有显著差异(P>0.05)。结果表明,Ob基因的TT基因型对猪的肉质和胴体性状具有显著的正遗传效应。     

Comparative study of the characteristics of the carcass and the meat of the Chato Murciano pig and its cross with Iberian pig, reared indoors

The Chato Murciano pig is a breed catalogued as a Special Protection breed in danger of extinction. At present it is commonly reared in an intensive system. We have studied the mineral composition and other characteristics of its carcass and meat. Samples from the Musculus longissimus lumborum were taken from a total number of 43 animals, divided into two groups, Chato Murciano and Chato Murciano crossed with Iberian, reared in a conventional indoor system. The resulting meat of the Chato Murciano pig and its cross with Iberian was especially rich in iron and copper, rich in phosphorus, and marginally poor in calcium and sodium. The evolution of the pH of the carcass was that of pigs which do not produce PSE (pale, soft and exudative) meat. Some relevant positive correlation coefficients between minerals (P ≤ 0.05) have been found.     

Validation of the QTL on SSC4 for meat and carcass quality traits in a commercial crossbred pig population

Porcine chromosome 4 harbours many quantitative trait loci (QTL) affecting meat quality, fatness and carcass composition traits, detected in resource pig populations previously. However, prior to selection in commercial breeds, QTL identified in an intercross between divergent breeds require confirmation, so that they can be segregated. Consequently, the objective of this study was to validate several QTL on porcine chromosome 4 responsible for meat and carcass quality traits. The experimental population consisted of 14 crossbred paternal half-sib families. The region of investigation was the q arm of SSC4 flanked by the markers S0073 and S0813. Regression analysis resulted in the validation of three QTL within the interval: Minolta a * loin, back fat thickness and the weight of trimmed ham. The results were additionally confirmed by factor analysis. Candidate genes were proposed for meat colour, which was the most evident QTL validated in this study.     

兰州市肉与肉制品微生物污染状况的研究

目的：了解兰州市定点屠宰场生猪屠宰加工产品的卫生质量以及肉与肉制品致病菌污染状况。方法：2003-2006年,应用国标法对2个定点生猪屠宰场300份生猪胴体样品进行了菌落总数、大肠菌群和沙门氏菌检验;采用随机采样法对兰州市不同酒店和超市的生猪肉、牛肉、羊肉、禽肉100份,熟肉制品1 200份进行了常见致病菌的检验。结果：生猪胴体体表和肉样沙门氏菌检出率分别为7.5%和14%;生肉检出致病菌阳性20份,总检出率为20%;熟肉制品检出致病菌阳性39份,阳性率为3.25%。生肉中以猪肉致病菌阳性率最高,为20%。结论：兰州市生猪胴体的卫生质量急需提高,屠宰生产加工水平亟待改善。     

Effect of candidate gene polymorphisms on reproductive traits in a Large White pig population

The objective of this study was to test for association of candidate single nucleotide polymorphisms (SNPs) with sow prolificacy reproductive traits, such as litter size, ovulation rate and lifetime performance, in gilts of a Large White pig population. Preliminary research on 25 animals selected from the high‐ and low‐performance groups of 347 animals with case‐control studies indicated that seven genes were associated with total number of piglets born (TNB). Six of the seven genes were associated with reproductive traits, including TNB, number of piglets born alive (NBA) and average weight of piglet weaning (AWW). A MBL2 SNP was significantly associated with TNB and NBA in first parity. A CFB SNP was associated with TNB in first parity. An ACE SNP was associated with TNB in first and second parities. An EGF polymorphism was associated with TNB, NBA and AWW in second parity. A KCNC2 polymorphism was significantly associated with TNB and NBA in second parity. A SLC22A5 SNP was associated with TNB and NBA in second parity. Six candidate SNPs were associated with TNB; the only exception was a PRKAG3 polymorphism. A candidate gene approach enables some of these polymorphisms to be used in genetic improvement programs based on marker‐assisted selection.     

Polymorphisms in genes of the somatotrophic axis are independently associated with milk production, udder health, survival and animal size in Holstein-Friesian dairy cattle

The somatotrophic axis consisting of pituitary-derived growth hormone and circulating insulin-like growth factor 1 has been well established as key regulators of animal health, metabolism, lactation, fertility, body composition and growth rate. The aim of this study was to simultaneously quantify the associations between SNPs in candidate genes of the somatotrophic axis (i.e., IGF-1, GH1 and GHR) with performance traits in Holstein-Friesian (HF) dairy cattle. Both novel SNPs identified previously by this group alongside other published SNPs within these genes were analysed for associations with performance in dairy cattle. Multiple regression analyses regressing genetic merit of up to 848 HF sires on novel SNPs (n = 76) and published SNPs (n = 33) were undertaken using weighted animal mixed linear models. Twenty-three SNPs were significantly associated with at least one of 18 traits analysed and involved in milk production, udder health, fertility and growth. Eight traits including milk fat composition, carcass conformation, stature, chest width, body depth, rump width, carcass and cull cow weight were independently associated with SNPs in two genes. Furthermore, for several traits including milk fat yield, somatic cell count, survival and carcass fat, SNPs in all three genes were independently associated with performance. Milk fat yield and carcass fat showed the highest number of independent associations across all three genes with five SNPs associated with both traits. The cumulative effects of the favourable alleles of all five SNPs across GH1, GHR and IGF-1 result in an increase of 5.9 kg and 28.6 units of milk fat and carcass fat, respectively. Cow survival was associated with a single SNP in each of the three genes with a cumulative allele effect of 1.5%. Independent effects of polymorphisms in GH1, GHR and IGF-1 reinforce the central role of the somatotrophic axis on animal development and performance.     

Effects of the rearing system on the quality traits of the carcass, meat and fat of the Chato Murciano pig

To evaluate the performance of the Spanish autochthonous pig breed Chato Murciano under different rearing conditions, a total of 30 castrated male pigs were used. Eighteen pigs were reared in an outdoor system, and sent to slaughter with an average age of 210 days and live weight (LW) of 124.41 kg; and 12 pigs were reared in an indoor system, and slaughtered with 119.58 kg of LW and 236 days old. The pigs reared outdoors showed a better growing rate and final live weight in relation to age, as well as higher hot and cold carcass yields, and superior weights for the most valuable meat cuts, but their morphometric parameters were similar to those of the pigs reared indoors. The rearing system did not affect many of the meat quality traits (intramuscular fat (IMF) content, pH, color, tenderness and cooking loss), but drip losses were higher in the outdoor group. The levels of IMF found in this study in both rearing systems (2.65–3.19%) were notably lower than those from previous studies, probably due to differences in the diet used. The rearing system affected the mineral and fatty acid (FA) composition. The distribution of fatty acids in both groups, with a low Polyunsaturated Fatty Acid (PUFA) content, can be expected to produce good quality processed products.     

Associations of the variation in the porcine myogenin gene with muscle fibre characteristics, lean meat production and meat quality traits

Pig breeding is aimed at improving lean meat production ability as well as meat quality, and muscle fibre characteristics may be important for enhancing these traits. Therefore, new molecular markers have been demanded for selecting lean meat production ability and meat quality in live animals. Myogenin belongs to the MyoD gene family, and is a candidate gene responsible for muscle fibre characteristics. We identified a new single nucleotide polymorphism (SNP) site in the 5' upstream region of the myogenin gene (nucleotides C and T). A total of 252 pigs of three breeds were genotyped by polymerase chain reaction–restriction fragment length polymorphism using BspCNI . Additionally, they were genotyped for the previously detected Msp I site in the 3'-flanking region (alleles A and B). The CCBB diplotype had the highest frequency over breeds, followed by TCBB and CCAB. The other diplotypes were not found in studied pigs. Association analysis performed for the markers found that the TCBB diplotype has desirable effects on the total number of fibres (p   < 0.002), fibre cross-sectional area (p   < 0.06), and loin eye area (p   < 0.001) than the other diplotypes. Moreover, the diplotype had the highest muscle pH value (p   < 0.07) and all meat quality traits were near the upper limit of the normal range as a reddish pink, firm and non-exudative (RFN) pork. Therefore, we suggest that selection for the myogenin diplotypes could improve total muscle fibre number, size and lean meat production ability with good meat quality.     

四川6个地方猪种的育肥和胴体性能以及肉质和风味物质比较研究

为了研究四川地方猪的种质特性,本试验测定了成华猪、雅南猪、青峪猪、内江猪、丫杈猪和凉山猪6个纯种地方猪的肥育性能、胴体性能、肉质常规理化指标和代谢组(滋味物质和挥发性风味物质)相关肉质指标.结果:丫杈猪的日增重、料重比、屠宰率和眼肌面积均显著或极显著地优于成华猪(P＜0.01或P＜0.05),油酸+亚油酸和己醛+壬醛含...     

Novel variants within the coding regions of the Slc11A1 gene identified in Bos taurus and Bos indicus breeds

Although in the cow the genetic resistance to brucellosis has been previously attributed to the Slc11A1 gene encoding Nramp1 protein, none of the mutations described to date seems to be the cause. To be able to associate another polymorphism of the gene to brucellosis resistance, we characterized the gene and identified in different breeds of Bos taurus and Bos indicus, six new variants among a total of 11 single nucleotide mutations, of which five occurred in the coding sequence (three are missense mutations), one in the promoter region and five in introns. The allelic and genotypic frequencies calculated revealed differences (p < 0.05) among the breeds studied.     

牛CAPN3基因多态性及与肉质性状相关性分析

以中国草原红牛、西门塔尔牛、利木赞牛、天一冈山黑牛为试验对象,利用PCR-SSCP结合测序的方法进行SNPs检测,并采用SPSS软件分析CAPN3基因的遗传多态性与肉质性状的关系。结果表明,仅在草原红牛及天一冈山黑牛中发现第46 414处（NC_007308）发生G→T的突变,且发生G→T突变的位点所对应不同基因型的个体,其大理石花纹、失水率、滴水损失和剪切力这些肉质性状存在显著差异,而西门塔尔牛和利木赞牛中未发现此突变。     

Association of DGAT2 gene polymorphisms with carcass and meat quality traits in domestic pigeons (Columba livia)

1. Diacylglycerol acyltransferase (DGAT) plays an important role in the synthesis of triacylglycerol, but its effects on meat quality and carcass composition in pigeons are unclear. In this study, single-nucleotide polymorphisms (SNPs) in the exons of the DGAT2 gene were identified and analysed by using DNA sequencing methods in 200 domestic pigeons (Columba livia). The associations between DGAT2 polymorphisms and carcass and meat quality traits were also analysed.

2. Sequencing results showed that 5 nucleotide mutations were detected in exons 3, 4, 5 and 6 of the DGAT2 gene. The analysis revealed three genotypes (AA, AB and BB) in G18398T and G22484C, in which the AA genotype and A allele had the highest frequency.

3. In the SNP of G18398T located in exon 5, individuals with genotype BB had significantly higher meat quality and lower abdominal fat content than those with AA or AB genotype. In the SNP of G22484C located in exon 6, the genotype AA showed highest carcass trait values, while the genotype BB represented better meat quality, compared to AA and AB genotypes.

4. The results imply that DGAT2 gene has a close relationship with carcass and meat quality traits in pigeons, and the SNPs of G18398T and G22484C can be used as genetic markers for marker-assisted breeding in pigeon.     

Use of bioinformatic SNP predictions in differentially expressed genes to find SNPs associated with Salmonella colonization in swine

Asymptomatic Salmonella-carrier pigs present a major problem in preharvest food safety, with a recent survey indicating >50% of swine herds in the United States have Salmonella-positive animals. Salmonella-carrier pigs serve as a reservoir for contamination of neighbouring pigs, abattoir pens and pork products. In addition, fresh produce as well as water can be contaminated with Salmonella from manure used as fertilizer. Control of Salmonella at the farm level could be through genetic improvement of porcine disease resistance, a potentially powerful method of addressing preharvest pork safety. In this research, we integrate gene expression profiling data and sequence alignment-based prediction of single nucleotide polymorphisms (SNPs) to successfully identify SNPs in functional candidate genes to test for the associations with swine response to Salmonella. A list of 2527 genes that were differentially regulated in porcine whole blood in response to infection with Salmonella enterica serovar Typhimurium were selected. In those genes, SNPs were predicted using ANEXdb alignments based on stringent clustering of all publically available porcine cDNA and expressed sequence tag (EST) sequences. A set of 30 mostly non-synonymous SNPs were selected for genotype analysis of four independent populations (n = 750) with Salmonella faecal shedding or tissue colonization phenotypes. Nine SNPs segregated with minor allele frequency ≥15% in at least two populations. Statistical analysis revealed SNPs associated with Salmonella shedding, such as haptoglobin (HP, p = 0.001, q = 0.01), neutrophil cytosolic factor 2 (NCF2 #2, p = 0.04, q = 0.21) and phosphogluconate dehydrogenase (p = 0.066, q = 0.21). These associations may be useful in identifying and selecting pigs with improved resistance to this bacterium.     

广西规模猪场猪呼吸道疾病综合征的病原学调查

为了解猪呼吸道疾病综合征(PRDC)在广西规模场猪群中的感染状况,采用PCR和RT-PCR方法,对2007～2009年期间采自广西13个市65个规模猪场的281份疑似PRDC感染组织样品进行了12种病原体检测。结果显示:73.85%(48/65)的猪场和71.87%(202/281)的组织样品为PRDC感染,其中,被猪繁殖与呼吸综合征病毒(PRRSV)、猪圆环病毒2型(PCV2)、猪瘟病毒(CSFV)、猪链球菌(SS)、猪伪狂犬病毒(PRV)、败血性波氏杆菌(Bb)、猪附红细胞体(E-su is)、猪流感病毒(SIV)、产毒素多杀性巴氏杆菌(T+PM)、副猪嗜血杆菌(HP)、猪细小病毒(PPV)和猪传染性胸膜肺炎放线杆菌(APP)感染(包括混合感染)的阳性样品分别占49.11%(138/281)、34.52%(97/281)、9.60%(27/281)、8.19%(23/281)、6.41%(18/281)、6.41%(18/281)、6.05%(17/281)、6.14%(15/281)、4.63%(13/281)、3.91%(11/281)、0.36%(1/281)和0.00%(0/281);单纯感染占28.11%(79/281);混和感染占43.77%(123/281)。二重、三重和四重混合感染分别占28.11%(79/281)、12.46%(35/281)和3.20%(9/281)。其中,以PRRSV+PCV2(+其他)混合感染形式较多见,占所有混合感染样品的52.03%(64/123)。细菌性病原体感染样品占20.28%(57/281),其中19.22%(54/281)为混合感染。可见:广西地区规模猪场普遍存在PRDC感染,其中PRRSV和PCV2是引起PRDC的主要病原;感染类型复杂多样,以PRRSV+PCV2(+其他)混合感染最为常见。