猪IGF2基因外显子3的遗传多态性及遗传效应分析

采用PCR-SSCP方法检测猪胰岛素样生长因子2(insulin-like growth factor 2,IGF2)基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应,根据猪IGF2基因的DNA序列(AY044828)设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现1GF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型(A36A/G109G.A36T/G109A和T36T/A109A),统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著(P＜0.01);其它猪种间基因型分布差异均不显著(P＞0.05),固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著(P＜0.05),而断奶重和6月龄重基因型间差异不显著(P＞0.05),最小二乘分析结果表明,A36A/G109G基因型个体同A36T/G109A和T36T/A109A基因型个体比较初生重和背膘厚的差异显著(P＜0.05),3种基因型初生重的大小排列顺序为A36A/G109G＜A36T/G109A＜T36T/A109A,背膘厚的大小排列顺序为A36A/G109G＞A36T/G109A＞T36T/A109A.因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择,将可以改善猪肉品质,加快猪的育种进程.     

猪IGF2基因外显子3的遗传多态性及遗传效应分析

采用PCR-SSCP方法检测猪胰岛素样生长因子2 (insulin-like growth factor 2,IGF2)基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应.根据猪IGF2基因的DNA序列（AY044828）设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现IGF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型（A36A/G109G,A36T/G109A 和 T36T/A109A）.统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著（Ｐ<0.01）;其它猪种间基因型分布差异均不显著（Ｐ>0.05）.固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著（Ｐ<0.05）,而断奶重和6月龄重基因型间差异不显著（Ｐ>0.05）.最小二乘分析结果表明,A36A/G109G基因型个体同A36T/G109A和 T36T/A109A基因型个体比较初生重和背膘厚的差异显著（Ｐ<0.05）,3种基因型初生重的大小排列顺序为A36A/G109G < A36T/G109A < T36T/A109A,背膘厚的大小排列顺序为A36A/G109G > A36T/G109A >T36T/A109A.因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择,将可以改善猪肉品质,加快猪的育种进程.     

猪MyoG基因内含子1的一个遗传多态性及其遗传效应分析

以长白猪(73),大白猪(68),沂蒙黑猪(57)和莱芜猪(83)为研究对象,采用PCR-SSCP方法 对猪MyoG基因遗传多态性进行分析,并研究基因型与初生重、日增重、肌肉嫩度和背膘厚的相关性.根据猪MyoG 基因的DNA序列（M14331）设计引物,结果在内含子1扩增的片段上发现了一个多态性,检测到2个等位基因(A、B),3种基因型（AA、AB、BB）,并对纯合子进行测序,发现2　943位G→C突变.基因型在不同猪种分布的多重比较,结果表明,大白猪与长白猪、沂蒙黑猪和莱芜猪比较差异显著（P<0.05）,莱芜猪与长白猪和沂蒙黑猪比较差异显著（P<0.05）,长白猪与沂蒙黑猪比较差异不显著（P>0.05）.固定效应模型分析结果表明,初生重及嫩度基因型间差异显著（P<0.01）,而日增重及背膘厚基因型间差异不显著（P>0.05）.最小二乘分析结果表明,BB基因型个体与AA基因型个体比较肌肉嫩度的差异显著（P<0.05）,AA基因型个体与AB和BB基因型个体比较背膘厚的差异显著（P<0.05）.因此,推测MyoG基因对猪肉品质、生长速度及背膘厚存在一定的影响,将 MyoG基因应用于猪育种过程中的标记辅助选择将可以改善猪肉品质,提高生长速度,加快猪的育种进程.     

猪ATF4基因多态性与生产性状的关联及基因表达分析

为进一步了解和认识ATF4基因的功能,揭示ATF4对猪脂肪代谢的影响,寻找与肉质性状相关联的分子标记,文章采用PCR方法扩增了ATF4基因部分序列,通过序列比对发现在翻译起始密码子ATG下游159 bp处存在A159G转换,通过PCR-AluⅠ-RFLP对大白猪、长白猪、梅山猪和通城猪进行酶切分型,发现在大白猪和长白猪中均为AA基因型,在梅山猪和通城猪中均为GG基因型。进一步对大白猪×梅山F2群体资源家系进行了酶切分型,并分析该位点的多态性与生产性状的关系。结果表明,ATF4的多态性与臀部平均膘厚存在极显著相关(P<0.01),与胸腰椎间膘厚、平均膘厚、眼肌高、眼肌面积存在显著相关(P<0.05)。采用Real-time PCR分析了ATF4基因在大白猪与梅山猪背最长肌不同发育阶段的表达模式。结果表明,ATF4基因在大白猪和梅山猪胚胎期65 d和出生后3 d中的表达水平相对都比较低,且在两品种间无明显差异;而在出生后60 d和120 d,ATF4基因在大白猪中与梅山猪均出现了上调表达,并且在梅山猪中的相对表达水平要显著高于大白猪。研究结果为进一步深入研究猪ATF4基因在脂肪代谢中的分子机理奠定了基础。     

猪IGF2基因外显子4b的遗传多态性及其遗传效应

采用PCR-SSCP方法检测猪胰岛素样生长因子2(insulin-like growth factor 2,IGF2)基因外显子4b的多态性,并分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应。根据猪IGF2基因的DNA序列(AY044828)设计引物,在exon4b上发现了一个多态性位点,并对纯合子进行测序,发现13位C→A转换,且存在3种基因型(AA、AB、BB)。统计结果表明,3种基因型在各品种中的分布不一致,长白猪与大白猪比较,莱芜猪与大薄莲猪比较,沂蒙黑猪和里岔黑猪比较差异不显著(P>0.05);其他猪种间基因型分布的差异均显著(P<0.05)。固定效应模型分析结果表明,初生重,断奶重和背膘厚基因型间差异显著(P<0.05),而6月龄重基因型间差异不显著(P>0.05)。最小二乘分析结果表明,BB基因型个体同AA和AB、基因型个体比较初生重和断奶重的差异显著(P<0.05),3种基因型在初生重和断奶重的大小排列顺序为AA>AB>BB;AA基因型个体同AB和BB基因型个体比较背膘厚的差异显著(P<0.05),3种基因型在背膘厚的大小排列顺序为BB>AB>AA。因此,推测IGF2基因对个体的生长速度和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择可以加快猪的育种进程。     

不同品种猪肌肉生长抑制素基因单核苷酸多态性分析

用PCR-RFLPs和PCR-SSCP分析方法,对"双肌臀”大白猪、大白猪、长白猪、杜洛克、汉普夏、皮特兰、二花脸、东北民猪、湖北白猪和部分杂交猪等不同品种猪肌肉生长抑制素基因3＇编码区、5＇调控区及内含子1区3个单核苷酸多态性位点(SNPs)进行了分析.结果表明,3＇编码区的SNP发生的频率较低,在274头猪中未检出突变纯合体.对5＇调控区的SNP,引进猪种(大白猪、长白猪、杜洛克、汉普夏和皮特兰)及其杂交猪以等位基因T为主,二花脸和湖北白猪则以等位基因A为主,均偏离Hardy-Weinberg平衡状态(P＜0.01).东北民猪的3种基因型近乎相等,处于Hardy-Weinberg衡状态.对内含子1区的SNP,大白猪及其与长白猪的杂交猪等位基因G占优势,二花脸和湖北白猪则以等位基因A为主,均偏离Hardy-Weinberg平衡状态(P＜0.01);东北民猪和大二猪的等位基因G和A近乎相等,处于Hardy-Weinberg平衡状态."双肌臀”大白猪在5＇调控区和内含子1区这两个位点的A等位基因稍高于普通大白猪.5＇调控区和内含子1区SNPs所产生的等位基因表现出连锁遗传现象.     

秦川牛IGF2基因SNPs检测及其与胴体、肉质性状的相关性

采用PCR-SSCP方法对186头24月龄秦川牛IGF2基因进行了SNPs多态性检测, 并将其与部分胴体和肉质性状进行关联分析。在IGF2基因120碱基处发现C→T 突变, 在279碱基处发现 A→G 突变。方差分析结果表明: BB、DD 两个位点与胴体性状中与宰前活重、胴体重、胴体长、胴体胸深、眼肌面积显著相关(P<0.05), 其中背部皮下脂肪厚达到差异极显著(P<0.01); 与肉质性状大理石花纹、嫩度、pH24 (牛肉排酸24 h后的酸度值)显著相关(P<0.05)。但是在胴体深、系水力指标中差异不显著(P>0.05)。A、D 等位基因是群体中的优势等位基因, AA、DD 基因型是优势基因型, 而含有B、D 等位基因的个体的胴体和肉质性状优于其他个体, 尤其有着极强脂肪沉积能力     

猪IGF2基因的遗传多态性及其遗传效应分析

采用PCR-SSCP方法检测胰岛素样生长因子2 (insulin-like growth factor 2, IGF2)基因外显子7, 8, 9的多态性, 并分析其对初生重、断奶重、6月龄重和6月龄背膘厚的遗传效应。根据猪IGF2基因的DNA序列(AY044828)设计3对引物, 结果在Ex8引物对扩增的片段上发现了多态性, 并对纯合子进行测序, 发现exon8的53位存在C→T转换, 且检测到3种基因型(AA、AB、BB)。统计结果表明, 3种基因型在各品种中的分布不一致, 长白猪与大白猪比较, 莱芜猪与大薄莲猪比较, 沂蒙黑猪和里岔黑猪比较差异不显著(P > 0.05); 其他猪种间基因型分布的差异均显著(P < 0.01)。固定效应模型分析结果表明, 初生重和6月龄背膘厚基因型间差异显著(P < 0.05), 而断奶重和6月龄重基因型间差异不显著(P > 0.05)。最小二乘分析结果表明, BB基因型个体同AA和AB基因型个体比较初生重的差异显著(P < 0.05), 3种基因型在初生重的大小排列顺序为AB > AA > BB; AA基因型个体同AB和BB基因型个体比较6月龄背膘厚的差异显著(P < 0.05), 3种基因型在6月龄背膘厚的大小排列顺序为BB > AB > AA。因此, 推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响, 将IGF2基因应用于猪育种过程中的标记辅助选择可以加快猪的育种进程。     

猪esr基因反转录转座子插入多态性及其与大白猪生产性能的关联性分析

雌激素受体 (Estrogen receptor,esr) 介导雌激素影响相关基因表达,从而调控哺乳动物的生长和繁殖机能。为了探讨esr基因的反转录转座子多态性对猪生长性能的影响,文中应用比较基因组学和生物信息学方法,预测猪esr基因的反转录转座子插入位点,采用PCR方法验证不同品种猪中插入多态性,并将该基因型与大白猪性能进行关联分析。结果显示,esr1和esr2基因验证后得到4个反转录转座子多态性位点,分别是位于esr1基因内含子2的esr1-SINE-RIP1、位于内含子5的esr1-LINE-RIP2和esr1-SINE-RIP3,以及位于esr2基因内含子1的esr2-LINE-RIP。其中esr1-SINE-RIP1的287 bp SINE插入对大白猪的活体背膘厚和100 kg体重背膘厚有显著影响 (P<0.05) ,纯合有插入 (SINE+/+) 的活体背膘厚和100 kg体重背膘厚显著高于杂合有插入 (SINE+/-) 和无插入 (SINE-/-) 型。这表明esr1-SINE-RIP1位点可作为分子标记辅助选育大白猪的背膘厚性状。     

生长激素基因(GH2)多态性与猪部分生产性能的关系

采用PCR -RFLP对南昌白猪 (117头 )和大约克夏猪 (36 1头 )的GH 2基因 - 119～ +486bp的片段进行了扩增 ,并用ApaⅠ酶切 ,产生了 2个等位基因A(44 9+10 1+5 5bp)和B(316 +133+10 1+5 5bp)。分析了不同基因型对个体初生重、2月龄重、4月龄重、6月龄重、校正背膘厚、平均背膘厚、瘦肉率和料重比等生产性能的影响。结果表明 ,在南昌白猪中 ,不同GH 2基因型间在所测的生产性能上差异不显著 (P >0 0 5 ) ;在大约克夏猪中 ,AA型猪的瘦肉率最低、与BB型猪相比 ,差异显著 (P <0 0 5 )。     

MyoG基因的遗传效应分析

实验采用PCR-RFLP技术分析了不同品种猪MyoG基因3′端MspⅠ位点的多态性,应用单标记回归模型分析了不同基因型与相关性状间的关联性及不同等位基因的遗传效应。结果表明：N等位基因能极显著地增加胴体瘦肉率和眼肌面积,降低皮脂含量（P<0.01）,改善胴体产肉量和提高胴体品质;同时,不同基因型对肉质性状的遗传影响作用较大,表现为N等位基因能极显著地降低猪肉品质,使pH值、肉色和肌内脂肪含量降低,并使肌肉的系水力变差（P<0.01）。N等位基因对增加胴体瘦肉率的加性效应值和显性效应值分别为3.929%和-0.602%;对增加眼肌面积的加性效应值和显性效应值分别为2.0985 cm2和-0.5775 cm2;对皮脂率的加性效应值为-3.0245%,显性效应值为-0.4045%。N等位基因对pH1的加性效应值和显性效应值分别为-0.167和0.034;对贮藏损失的加性效应值和显性效应值分别为0.558和-0.347;对肌内脂肪含量的加性效应值和显性效应值分别为-0.963和-0.217。但MyoG基因3′端MspⅠ位点的突变对FOM肉脂仪测定的胴体等级性状的影响不显著（P>0.05）。     

Quantitative trait loci for carcass traits on pig chromosomes 4, 6, 7, 8 and 13

For 22 carcass traits, we identified 16 QTLs (based on data for pig resource population no. 214, including 180 F2 hybrids of 3 Yorkshire boars and 8 Meishan sows) and mapped them with the use of 39 microsatellite marker loci on chromosomes 4, 6, 7, 8 and 13. Five QTLs were highly significant (P < or = 0.01 at chromosome level): for skin weight (on chromosome 7 at SW1856 and on chromosome 13 at SW1495), skin percentage (on chromosome 7 between SW2155 and SW1856 and on chromosome 13 between SW1495 and SW520), and ratio of leg and butt to carcass (on chromosome 4 at SW1996). The remaining 11 QTLs were significant (P < or = 0.05 at chromosome level): for backfat thickness at shoulder, loin eye width, loin eye height, fat meat weight, lean meat weight, skin weight, bone weight, skin percentage, fat meat percentage, and ratio of lean meat to fat meat. The proportion of phenotypic variance explained by these QTLs ranged from 0.06% (QTL for loin eye width on chromosome 8 between SW1037 and SW1953) to 18.04% (QTL for ratio of lean meat to fat meat on chromosome 7 between SW252 and SW581). Seven of the QTLs reported here are novel.     

Myf-6基因在不同猪种中的PCR-RFLP遗传多态性及其遗传效应分析

作为生肌调节因子家族的一个成员,Myf-6基因在肌形成的过程中发挥着重要的作用。实验采用PCR-RFLP技术分析了Myf-6基因在12个中外猪种及部分杂交群体中的分布情况,并分析了Myf-6基因对肌纤维、胴体品质、胴体等级性状和肉质性状的遗传效应。结果表明：Myf-6基因内含子1内的Ava I酶切位点多态性不丰富,多数中国地方猪种群体中A等位基因已经完全固定,B等位基因仅以较低的频率存在于外种猪或含外种猪血缘的杂交群体中。尽管没有检测到BB纯合个体,但AB杂合子的平均瘦肉率为50.344 %,极显著地高于AA纯合子的45.875 %(P<0.01)。AB杂合子的眼肌面积为27.097 cm2,极显著地大于AA纯合子的22.572 cm2(P<0.01)。AB杂合子的皮脂率（39.889 %）极显著地低于AA纯合子（44.503 %）(P<0.01)。上述结果说明本次试验群体中的B等位基因具有增加胴体瘦肉率和眼肌面积,降低胴体脂肪含量从而改善胴体品质的遗传效应。此外,Myf-6基因对肌纤维生长性状、FOM肉脂仪测定的胴体等级性状以及肉质性状等都没有显著影响(P>0.05)。     

Polymorphisms of the 5′ regulatory region of the porcine <Emphasis Type="Italic">PPARGC1A</Emphasis> gene and the effects on muscle fiber characteristics and meat quality

The purpose of this study was to determine the structure of the porcine PPARGC1A 5′ upstream region, and to find suitable molecular markers for improved meat quality and good lean meat production. Ten DNA polymorphisms, including 7 SNPs, 2 microsatellites, and 1 insertion or deletion were newly found in the 5′ upstream region of PPARGC1A. Three SNPs that had restriction enzyme site were evaluated for associations with muscle fiber characteristics and production traits. Two hundred fifty-two pigs (Yorkshire and Landrace) were used in this analysis. The c.-2894G>A genotypes was significantly associated with muscle fiber characteristics, including the number of fiber type I and IIb composition (P < 0.05), mean cross-sectional area of fibers (P < 0.01), and fiber number per unit area (P < 0.05). The animals with the GG genotype had a higher percentage of type I fibers and a lower percentage of type IIb fibers with better meat quality [higher pH value (P < 0.05) and lower drip loss (P < 0.05)] and lean meat production [larger loin eye area (P < 0.05)]. Moreover, the mRNA expression levels of PPARGC1A among genotypes were significantly different with the highest level of GG genotype. The c.-2885G>T and c.-1402A>T sites showed similar results that had significant effects on the mean cross-sectional area (CSA; P < 0.05), fiber number per unit area (P < 0.05) and loin eye area (P < 0.01). Therefore, we suggest that the c.-2894G>A polymorphism in the 5′ upstream region of the porcine PPARGC1A gene can be used as a meaningful molecular marker for simultaneous improvement of lean meat production and quality traits.     

Effects of the monoclonal antibody against porcine 40 kDa adipocyte-specific plasma membrane protein on adipocytes and carcass composition

The effects of the mouse monoclonal antibody against 40 kDa adipocyte-specific plasma membrane protein on porcine adipocytes and carcass composition were investigated in vitro and in vivo. Results revealed that the in vitro complement-mediated cytotoxicity of this monoclonal antibody can lead to adipocyte lysis, remarkable reduction of adipocyte lipid accumulation （P〈0.01）, and significant decrease of well-differentiated fat cells （P〈0.01）. Treatment of adipocytes with this antibody alone in vitro did not induce cell lysis, but could lead to noticeable reduction of well-differentiated cells and lipid accumulation （P〈0.05） at the pre-adipocyte stage. In vivo, pigs injected with 0.5 mg/kg or 1.0 mg/kg of antibody showed smaller adipocyte sizes （P〈0.01） and reduced lipid accumulation of adipocytes （P〈0.01）. Our results also indicated that pigs intraperitoneally or subcutaneously immunized with 0.5 mg/kg of monoclonal antibody at 15 kg or 1.0 mg/kg antibody at 60 kg had a higher lean meat percentage （P〈0.05）, larger loin eye area （P〈0.05）, lower fat meat percentage （P〈0.05）, less backfat thickness （P〈0.05） and smaller leaf fat weight （P〈0.05） than the control pigs, but other carcass traits such as caul fat weight, heart weight, liver weight, spleen weight, kidney weight, lung weight, and dressing percentage were not significantly affected. These results suggested that this monoclonal antibody could be applied to restrain excessive fat deposition in porcine production.     

Developmental changes of carcass composition, meat quality and organs in the Jinhua pig and Landrace

The present study was aimed to compare the developmental changes of carcass composition, meat quality characteristics and organ weight in pigs of different breeds. Six pigs (sex balance) of each breed were slaughtered at 35, 80 and 125 days of age, respectively. The carcass was chilled and the left carcass side was dissected into bone, lean meat, fat and skin; additionally, organ weight and meat quality parameters were observed. Carcasses of the Jinhua pig were lighter (P < 0.001), contained less lean meat percentage (P < 0.01) and more carcass fat percentage (P < 0.05) than did carcasses of the Landrace. L*-values were lower in Jinhua pigs than in Landrace at 125 days of age (P < 0.05), but the Jinhua pig had higher a*-values compared with Landrace at the age of 80 days (P < 0.01) and 125 days (P < 0.01), respectively. In addition, Jinhua pigs showed lower colour scores (P < 0.05), higher intramuscular fat (IMF) percentage (P < 0.05), less marbling scores (P < 0.05) and lower drip loss (P < 0.05) than Landrace. For organ weight, Jinhua pigs had higher relative heart weight at the age of 80 days (P < 0.05) and 125 days (P < 0.001), and higher relative liver weight at 125 days of age (P < 0.01) than that of Landrace. In addition, the relative kidney weight was heavier (P < 0.001) in the Jinhua pig than in the Landrace during the whole experiment. These results indicated that developmental changes of carcass composition, meat quality parameters and organ weight displayed breed differences. Jinhua pigs were fatter than Landrace but the former had better quality characteristics in the meat.     

H2AFZ,RNF4 and NR4A1 loci are associated with boar semen quality by population association studies

Abstract

Spermatogenesis is a complex process regulated by many genes. In this study, H2AFZ, RNF4 and NR4A1 genes were selected as candidate genes for boar semen quality traits based on their functions during spermatogenesis, and the associations of three loci (H2AFZ c.192?+?210–192?+?213delCGAT, RNF4 c.374?+?358 T?>?C and NR4A1 c.956?+?796 A?>?G) with sperm quality traits were analyzed in Duroc (n?=?185), Large White (n?=?87) and Landrace (n?=?49) pig populations. The results showed H2AFZ c.192?+?210–192?+?213delCGAT AA boars produced 1.52% lower abnormal sperm rate (ASR) than AB boars in Landrace pigs (p?<?0.05); RNF4 c.374?+?358?TC boars produced 0.31?×?10⁸/ml higher sperm concentration (SCON) than CC boars (p?<?0.05) in Large White pigs; NR4A1 c.956?+?796 A?>?G was associated with ASR in Duroc and Large White pigs and was associated with sperm motility (MOT) in Large White and Landrace pigs. This study indicated the H2AFZ, RNF4 and NR4A1 loci were the potential molecular markers for improving the semen quality traits in boars.     

Carcass composition and meat quality of indigenous Yanan pigs of China

The Yanan (YN) pig is a traditional Chinese indigenous breed that is raised in southwest China in the Sichuan Province, but there is little data on the germplasm characteristics of this breed. To evaluate carcass characteristics and meat quality of the YN pig, we compared carcass and meat quality of YN pigs and Landrace × Yanan (CY) hybrid pigs; 30 YN pigs and 30 CY pigs weighing 20 ± 2 kg were reared and slaughtered at the normal slaughter weight (100-120 kg). The carcasses were chilled and the left carcass side was dissected into bone, lean meat, fat, and skin; meat quality parameters were measured. Carcasses of YN pigs were lighter (88.85 vs 90.05 kg, P < 0.05) and shorter (71.88 vs 77.61 cm, P < 0.001); they contained less lean meat (41.60 vs 49.25%, P < 0.001), less ham and breech (25.93 vs 27.53%, P < 0.001) and less carcass bone (9.83 vs 10.53%, P < 0.01) than did carcasses of CY pigs. On the other hand, YN pigs had more carcass subcutaneous fat and skin (48.58 vs 40.23%, P < 0.001), thicker backfat (3.67 vs 3.43 cm, P < 0.001) and smaller loin muscle area (9.83 vs 26.91 cm(2), P < 0.001) compared with CY pigs. Among meat quality parameters, YN pigs had higher pH(1) (6.41 vs 6.17, P < 0.001), higher color score(u) (3.86 vs 3.36, P < 0.001) and lower Minolta L(u) values (40.89 vs 45.32, P < 0.01) than CY pigs. On the other hand, YN pigs had lower drip loss (1.31 vs 2.26%, P < 0.05) and lesser fiber area (2351.34 vs 3025.43 μm(2), P < 0.01) than CY pigs. Both breeds had high intramuscular fat (4.46% in YN and 4.45% in CY). No significant differences in other carcass traits and meat quality were found in the two populations. We conclude that YN pigs could be used in commercial pig production to provide good tasting and high-quality niche products.     

The effects of immunization against gonadotropin-releasing hormone on growth performance,reproductive activity and carcass traits of heavy weight gilts

Heavy weight gilts commonly show signs of oestrus during the late finishing phase, which results in a period of reduced feed intake and growth rate. Immunization against gonadotropin-releasing hormone (GnRH) (IM, immunocastration) was developed for finishing boars and recently extrapolated to females. Immunocastration acts by suppressing reproductive activity and improving the growth potential. The objective of this study was to evaluate the effects of IM on growth performance, reproductive activity and carcass characteristics of late finishing gilts. Seventy-two gilts (63.49 ± 0.39 kg) were either injected with saline (Intact) or immunized against GnRH (Immunized). The study consisted of three experimental periods: between the first to second immunization (V1 to V2, 15 to 19 weeks of age), from the second immunization to the beginning of daily boar exposure (DBE) (V2 to DBE, 19 to 21 weeks of age) and from the beginning of DBE to slaughter (S) (DBE to S, 21 to 25 weeks of age). Immunized gilts showed an overall increase (from 15 to 25 weeks) of 3.90 kg (P < 0.05) of live weight, 56 g (P < 0.05) of average daily gain (ADG) and 250 g (P < 0.001) of average daily feed intake (ADFI). Immunized gilts had a greater ADFI (+240 g, P < 0.05) and worse feed conversion ratio (+0.26, P < 0.05) from 19 (V2) to 21 weeks of age (before DBE). Furthermore, those females had higher feed intake (+410 g; P < 0.001) plus greater daily weight gain (+92 g; P < 0.05) from V2 to S, and from DBE to S (+470 g of ADFI, P < 0.001; +129 g of ADG, P < 0.01, respectively). Immunocastration had no effect on backfat thickness, lean meat percentage and weight, cold carcass yield or loin depth (P > 0.05). Immunized gilts showed 4.4% increased cold carcass weight (P < 0.01) and 10.6% greater gross flank weight (P < 0.001). Immunization against GnRH did not influence shoulder, collar, loin, belly or ham weights. Nor did it influence belly fat thickness, or meat, skin plus fat and bones yields of cold ham (P > 0.05). Immunocastration reduced ovarian and uterine weights by 82% (P < 0.001) and 93% (P < 0.001), respectively, and suppressed oestrus manifestation in all gilts in the immunized group (P < 0.001). These results indicate that immunization against GnRH is a promising tool for stimulating growth performance with no detrimental effects on carcass quality of heavy weight finishing gilts, by means of oestrus suppression.