亚麻油对育肥猪生产性能及猪肉脂肪酸组成的影响

试验旨在研究亚麻油(LO)对育肥猪生产性能及猪肉脂肪酸组成的影响。选用体重63 kg左右的健康大白猪84头,按体重相近的原则随机分为3组,每组设4个重复,每个重复7头猪。3个处理日粮为玉米-豆粕型日粮,分别添加0%、1.5%和3.0%的LO,试验时间50 d。结果表明:与对照组相比,日粮中添加LO对猪平均日增重无显著影响(P>0.05),但有降低平均日采食量(P>0.05)和饲料增重比的趋势(P>0.05);日粮中添加LO能显著提高猪背最长肌α-亚麻酸(ALA)、EPA以及n-3PUFA总含量(P<0.01),而对DHA、SFA和n-6PUFA含量无明显影响(P>0.05);日粮中添加1.5%和3.0%LO分别提高DPA 47.62%(P>0.05)和82.54%(P<0.05),分别降低花生四烯酸含量的26.12%(P>0.05)和15.29%(P>0.05),但两者间均差异不显著(P>0.05);日粮中添加1.5%和3.0%LO均显著降低二十二碳四烯酸含量(P<0.05),但两者间差异不显著(P>0.05)。结果提示,饲料中添加LO显著提高猪背最长肌ALA、EPA和n-3PUFA的含量,降低花生四烯酸和二十二碳四烯酸含量,对DHA含量没有显著影响;要将猪肉n-6:n-3PUFA降低到4.0以下需在日粮中添加3.0%LO。     

亚麻油对宁乡猪不同组织长链脂肪酸谱的影响

本试验旨在研究亚麻油对宁乡猪背肌和3种不同脂肪组织中长链脂肪酸谱的影响,并探究脂肪酸生成的潜在机制。选取日龄相近、平均体重(43.21±0.64) kg的宁乡阉母猪30头,随机分为2组,每组5个重复,每个重复3头。对照组饲喂基础饲粮,试验组在基础饲粮中添加2%亚麻油,试验期56 d。结果显示:与对照组相比,饲粮中添加2%亚麻油后,宁乡猪背肌中花生一烯酸(C20∶1)、γ-亚麻酸(C18∶3n-6)、α-亚麻酸(C18∶3n-3)含量显著提高(P0.05),花生四烯酸(C20∶4n-6)含量显著降低(P0.05);饲粮中添加2%亚麻油对3个脂肪组织中脂肪酸含量的影响与背肌趋于一致,如能显著提高背脂、腹脂和肾周脂中亚油酸(C18∶2n-6c)、C18∶3n-6、C18∶3n-3、二十碳三烯酸(C20∶3n-6)含量(P0.05),降低背脂和腹脂中油酸(C18∶1n-9c)(P0.05)、C20∶4n-6(0.05≤P0.10)及肾周脂中硬脂酸(C18∶0)含量(P0.05);同时,饲粮中添加2%亚麻油还能显著降低3种脂肪组织中n-6/n-3多不饱和脂肪酸(PUFA)比值(P0.05),使3种脂肪组织中平均n-6/n-3 PUFA比值降到5.92。此外,饲粮中添加2%亚麻油能显著下调背脂中乙酰辅酶A羧化酶α(ACCα)、γ-过氧化酶活化增生受体(PPARγ)和脂肪酸去饱和酶2(FADS2)基因的表达(P0.05),对α-过氧化酶活化增生受体(PPARα)基因的表达也有抑制趋势(0.05≤P0.10)。上述结果表明,饲粮中添加2%亚麻油能显著提高宁乡猪背肌、背脂、腹脂和肾周脂中C18∶3n-3含量,使3种脂肪组织中平均n-6/n-3 PUFA比值降至《中国居民膳食指南(2016)》推荐范围(4～6)内;这可能是通过调控细胞分化及抑制脂肪酸从头合成途径实现的。     

亚麻油对宁乡猪生长性能、胴体性状和肉品质的影响

本试验旨在研究饲粮添加亚麻油(LO)对宁乡猪生长性能、胴体性状和肉品质的影响。选取日龄相近、体重约43 kg的宁乡阉母猪30头,随机分为2组,每组5个重复,每个重复3头。对照组饲喂基础饲粮,试验组饲喂在基础饲粮中添加2%LO的试验饲粮,试验期8周。结果表明:与对照组相比,饲粮中添加2%LO后,宁乡猪的平均日采食量显著降低(P0.05),料重比有降低趋势(0.05≤P≤0.10);皮厚提高13.40%(0.05≤P≤0.10);肌肉剪切力降低21.89%(0.05≤P≤0.10),肌肉△pH提高21.37%(P0.05);肝脏苏氨酸(Thr)、丝氨酸(Ser)、甘氨酸(Gly)和精氨酸(Arg)含量显著提高(P0.05),谷氨酸(Glu)、丙氨酸(Ala)和赖氨酸(Lys)含量有提高趋势(0.05≤P≤0.10)。上述结果表明,饲粮中添加2%LO可以改善宁乡猪的饲料转化率,提高肌肉嫩度和肝脏中部分必需氨基酸(Thr、Ser)的含量,但会对宁乡猪的皮厚和肌肉pH产生一定的负面影响。     

亚麻籽对生长育肥猪生长性能、胴体性状、肉质和脂肪酸组成的影响北大核心CSCD

本试验旨在研究饲粮添加亚麻籽对生长育肥猪生长性能、胴体性状、肉质和脂肪酸组成的影响。试验选用(52.31±2.28) kg的生长猪72头,按体重随机分为3组,每组4个重复,每个重复6头猪。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加5%和10%亚麻籽的饲粮。试验分2个阶段(50~80 kg和81~110 kg),每个阶段结束时对猪进行称重,试验结束后每栏选2头接近平均体重猪进行麻醉屠宰。结果表明:1)与对照组相比,饲粮添加5%和10%亚麻籽显著降低了生长育肥猪50~80 kg阶段平均日采食量、料重比及50~110 kg阶段料重比(P<0.05),并且10%添加量还显著提高了50~80 kg阶段平均日增重(P<0.05)。2)饲粮添加亚麻籽能显著增加生长育肥猪眼肌面积(P<0.05),但对胴体长、屠宰率、平均背膘厚等胴体性状无显著影响(P>0.05)。3)饲粮添加5%和10%亚麻籽能显著降低生长育肥猪背最长肌n-6/n-3多不饱和脂肪酸(PUFA)值(P<0.05),显著提高α-亚麻酸、二十二碳烯酸、二十二碳二烯酸含量及PUFA总含量(P<0.05),且当添加量达到10%时,还能显著提高背最长肌中油酸和亚油酸含量(P<0.05)。结果提示,亚麻籽能一定程度提高生长育肥猪生长性能,增加背最长肌中n-3PUFA含量,降低n-6/n-3 PUFA值,且对胴体性状及肉质无负面影响。     

苜蓿草粉对育肥猪肉品质、肌肉氨基酸和脂肪酸含量的影响

本试验旨在探讨饲粮添加苜蓿草粉对育肥猪生长性能、肉品质、肌肉氨基酸和脂肪酸含量的影响。选择平均体重(60.28±0.73)kg的健康"长×大"或"大×长"二元育肥猪130头,随机分为5组,每组26个重复,每个重复1头猪。对照组饲喂基础饲粮,试验组在基础饲粮中分别添加5%、10%、20%和30%的苜蓿草粉。预试期7 d,正试期72 d。结果表明:1)5%苜蓿草粉组育肥猪的平均日增重(ADG)最高,增重成本最低。2)饲粮添加苜蓿草粉对育肥猪的肌肉p H45 m in、熟肉率、大理石纹和肉色无显著影响(P0.05);与对照组相比,各苜蓿草粉组的肌肉p H24 h极显著降低(P0.01);30%苜蓿草粉组的肌肉滴水损失显著低于对照组和5%苜蓿草粉组(P0.05)。3)与对照组相比,20%苜蓿草粉组育肥猪的肌肉鲜味氨基酸(DAA)(天冬氨酸、谷氨酸、甘氨酸、丙氨酸)、必需氨基酸(EAA)(蛋氨酸、缬氨酸、异亮氨酸、苯丙氨酸、亮氨酸、苏氨酸、赖氨酸)、组氨酸、精氨酸、酪氨酸、丝氨酸、脯氨酸及总氨基酸(TAA)含量显著提高(P0.05)。4)随饲粮苜蓿草粉添加水平的增加,育肥猪的肌肉饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)含量逐渐减少,肌肉不饱和脂肪酸(UFA)、多不饱和脂肪酸(PUFA)、n-6 PUFA和n-3PUFA含量逐渐增加。与对照组相比,20%和30%苜蓿草粉组的肌肉M UFA、油酸含量显著降低(P0.05),肌肉UFA含量显著提高(P0.05);20%和30%苜蓿草粉组的肌肉PUFA、亚油酸、α-亚麻酸、n-6 PUFA和n-3 PUFA含量均显著高于对照组、5%和10%苜蓿草粉组(P0.05);肌肉n-6 PUFA/n-3 PUFA含量极显著低于对照组、5%和10%苜蓿草粉组(P0.01)。综上,饲粮添加20%苜蓿草粉可使育肥猪的肌肉DAA、EAA含量以及PUFA中亚油酸、α-亚麻酸含量提高,n-6 PUFA/n-3 PUFA降低,有利于n-3 PUFA在肌肉中的富集,可以提高猪肉品质和营养价值。     

苜蓿草粉对育肥猪肉品质、肌肉氨基酸和脂肪酸含量的影响北大核心CSCD

本试验旨在探讨饲粮添加苜蓿草粉对育肥猪生长性能、肉品质、肌肉氨基酸和脂肪酸含量的影响。选择平均体重(60.28±0.73)kg的健康"长×大"或"大×长"二元育肥猪130头,随机分为5组,每组26个重复,每个重复1头猪。对照组饲喂基础饲粮,试验组在基础饲粮中分别添加5%、10%、20%和30%的苜蓿草粉。预试期7 d,正试期72 d。结果表明:1)5%苜蓿草粉组育肥猪的平均日增重(ADG)最高,增重成本最低。2)饲粮添加苜蓿草粉对育肥猪的肌肉p H45 m in、熟肉率、大理石纹和肉色无显著影响(P>0.05);与对照组相比,各苜蓿草粉组的肌肉p H24 h极显著降低(P<0.01);30%苜蓿草粉组的肌肉滴水损失显著低于对照组和5%苜蓿草粉组(P<0.05)。3)与对照组相比,20%苜蓿草粉组育肥猪的肌肉鲜味氨基酸(DAA)(天冬氨酸、谷氨酸、甘氨酸、丙氨酸)、必需氨基酸(EAA)(蛋氨酸、缬氨酸、异亮氨酸、苯丙氨酸、亮氨酸、苏氨酸、赖氨酸)、组氨酸、精氨酸、酪氨酸、丝氨酸、脯氨酸及总氨基酸(TAA)含量显著提高(P<0.05)。4)随饲粮苜蓿草粉添加水平的增加,育肥猪的肌肉饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)含量逐渐减少,肌肉不饱和脂肪酸(UFA)、多不饱和脂肪酸(PUFA)、n-6 PUFA和n-3PUFA含量逐渐增加。与对照组相比,20%和30%苜蓿草粉组的肌肉M UFA、油酸含量显著降低(P<0.05),肌肉UFA含量显著提高(P<0.05);20%和30%苜蓿草粉组的肌肉PUFA、亚油酸、α-亚麻酸、n-6 PUFA和n-3 PUFA含量均显著高于对照组、5%和10%苜蓿草粉组(P<0.05);肌肉n-6 PUFA/n-3 PUFA含量极显著低于对照组、5%和10%苜蓿草粉组(P<0.01)。综上,饲粮添加20%苜蓿草粉可使育肥猪的肌肉DAA、EAA含量以及PUFA中亚油酸、α-亚麻酸含量提高,n-6 PUFA/n-3 PUFA降低,有利于n-3 PUFA在肌肉中的富集,可以提高猪肉品质和营养价值。     

饲粮中添加β-羟基-β-甲基丁酸对巴马香猪生长性能和肝脏脂肪代谢的影响

本试验旨在研究饲粮中添加β-羟基-β-甲基丁酸(HMB)对巴马香猪生长性能和肝脏脂肪代谢的影响。试验选用32头体重[(8.58±0.21) kg]相近的(60±2)日龄的健康巴马香猪阉公猪,随机分为4组(每组8头猪),分别饲喂添加0(对照组)、0.13%、0.64%、1.28%HMB的饲粮。试验期60 d。结果表明:1)与对照组相比,饲粮中添加0.13%HMB显著提高了平均日增重和血清高密度脂蛋白(HDL)含量(P0.05);饲粮中添加1.28%HMB显著降低了血清HDL含量(P0.05),显著提高了血清胆固醇(CHOL)含量(P0.05)。2)与对照组相比,饲粮中添加0.13%HMB显著提高了肝脏二十二碳六烯酸(C22∶6n-3)含量(P0.05),显著降低了肝脏n-6/n-3多不饱和脂肪酸(PUFA)比值(P0.05)。3)与对照组相比,饲粮中添加0.13%HMB显著上调了肝脏中脂肪酸移位酶(HSL)和过氧化物酶体增殖子激活受体α(PPARα)的mRNA表达量(P0.05),而添加1.28%HMB则显著下调了肝脏中激素敏感酶(HSL)和脂肪酸转运蛋白-1(FATP-1)的mRNA表达量(P0.05)。综上所述,饲粮中添加适量(0.13%) HMB可改善巴马香猪的生长性能,增加肝脏中C22∶6n-3含量,并可改善肝脏脂肪代谢,其作用机制可能与PPARα信号通路相关。     

苏尼特羊体脂脂肪酸组成的研究

旨在了解年龄、育肥及解剖部位对苏尼特肉羊体脂脂肪酸组成的影响,为有效利用羊油脂提供依据。本研究从苏尼特左旗改良站种羊场放牧群中选取当年(1岁)、1.5岁和成年(3岁)羯羊各6只,育肥群中选取6只肥羔,进行屠宰测试,并分别采集尾油、板油、网油和胸椎上方皮下脂肪样品;同时采集草场混合牧草样品和育肥饲粮样品,并分别检测其脂肪酸组成。结果表明:(1)放牧饲粮的n-6/n-3为2.205,低于育肥饲粮(8.779);(2)随着年龄的增加苏尼特羊净肉率和胴体脂肪率极显著提高(P0.05),但1.5岁羊与成年羊之间无显著差异(P0.05);(3)随着年龄的增长苏尼特羊体脂中:1中链饱和脂肪酸(MCFA)组成上升(P0.05)。2n-3多聚不饱和脂肪酸(n-3PUFA)组成下降(P0.05)。3c18∶0组成和c4∶0等短链饱和脂肪酸(SCFA)组成上升(P0.05)。4c18∶1c9组成下降(P0.01)。5n-6/n-3和S/U上升(P0.05);(4)育肥使苏尼特羊体脂中:1MCFA组成上升(P0.05)。2n-3PUFA组成下降(P0.05),n-6/n-3提高(P0.05)。3c18∶0组成(P0.05)和SCFA组成(P0.01)上升。同时使c18∶1c9组成下降(P0.01);(5)在部位间:1饱和脂肪酸,网油和板油c18∶0组成高而c16∶0组成低(P0.01),相反皮下脂肪c16∶0组成高而c18∶0组成低(P0.01),相比之下,尾油上述2种脂肪酸组成则相对都较低(P0.01)。2不饱和脂肪酸,尾油c18∶1c9(P0.01)和n-3PUFA(P0.05)组成高,而n-6PUFA组成低(P0.05)。网油中n-6PUFA组成高,而c18∶1c9组成低。板油和皮下脂肪中上述3种脂肪酸组成则均很低。3皮下脂肪中MCFA组成显著高于其他3个脂肪组织(P0.01),而其他3个脂肪组织之间则无显著差异(P0.05)。4n-6/n-3为尾油(1.512)皮下脂肪(2.435)板油(2.468)网油(2.675)(P0.05)。说明,放牧组饲粮具有n-3PUFA营养特性,而育肥组饲粮则具有n-6PUFA营养特性;苏尼特肉羊早期生长发育速度显著高于后期,而且体脂沉积量也最佳;苏尼特羊体脂具有n-3PUFA营养特性,但年龄和育肥使体脂n-3PUFA营养特性明显降低;尾油PUFA的营养价值要明显高于网油和板油,最差的是皮下脂肪。另外,从脂肪酸对其风味的贡献看,尾油更优于其他3个脂肪组织,其中最差的也是皮下脂肪。     

半胱胺对宁乡猪胴体性状和肉品质的影响

本试验旨在研究饲粮中添加半胱胺对宁乡猪胴体性状和肉品质的影响。选取日龄相近、体重约43kg的宁乡阉公猪30头,随机分为2组,每组5个重复,每个重复3头,对照组饲喂基础饲粮,试验组在基础饲粮中添加80 mg/kg半胱胺,试验期8周。结果表明:1)与对照组相比,试验组屠宰率提高了3.04%(P0.05)。2)与对照组相比,试验组背最长肌滴水损失降低了21.83%(0.05≤P0.10)。3)与对照组相比,试验组背最长肌饱和脂肪酸中硬脂酸含量下降了6.71%(P0.05);单不饱和脂肪酸中反油酸含量降低了62.57%(P0.01),二十碳烯酸含量降低了28.02%(P0.01);多不饱和脂肪酸含量升高了7.14%(P0.05),其中亚油酸含量升高了7.89%(P0.05),二十碳三烯酸含量升高了34.10%(0.05≤P0.10),α-亚麻酸含量下降了15.87%(P0.01)。由此可知,在饲粮中添加半胱胺提高了宁乡猪屠宰率,通过降低硬脂酸和提高亚油酸的含量改善了肉品质。     

饲粮n-6/n-3多不饱和脂肪酸配比对北极狐冬毛期体脂沉积、体脂肪酸组成及血液生化指标的影响

本试验旨在研究饲粮n-6/n-3多不饱和脂肪酸(PUFA)配比对冬毛生长期雄性北极狐体脂沉积、体脂肪酸组成及血液生化指标的影响。试验选取48只157日龄,平均体重为(5 658±47)g的健康雄性北极狐,随机分成4组(每组12个重复,每个重复1只),分别饲喂n-6/n-3PUFA配比为3、18、41和136的试验饲粮,试验饲粮对应添加的油脂为12%鱼油和2%豆油(Ⅰ组),9.38%玉米油和4.62%豆油(Ⅱ组),12%玉米油和2%豆油(Ⅲ组),1.5%鱼油和12.5%玉米油(Ⅳ组)。预饲期7d,试验期40d。结果表明:1)饲粮n-6/n-3PUFA配比极显著影响北极狐肝体指数(P0.01),Ⅳ组极显著高于Ⅱ和Ⅲ组(P0.01),与Ⅰ组差异不显著(P0.05),对肝脂肪含量、肝脂率、皮下脂肪重、皮脂率均无显著影响(P0.05);2)饲粮n-6/n-3PUFA配比显著或极显著影响北极狐肌内脂肪饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、PUFA、n-6和n-3PUFA含量(P0.05或P0.01),Ⅰ组SFA显著高于Ⅱ组(P0.05),与Ⅲ和Ⅳ组差异不显著(P0.05),Ⅰ组MUFA显著高于Ⅲ和Ⅳ组(P0.05),与Ⅱ组差异不显著(P0.05),Ⅱ组PUFA极显著高于Ⅰ和Ⅳ组(P0.01),与Ⅲ组差异不显著(P0.05),Ⅰ和Ⅲ组n-3极显著高于Ⅱ和Ⅳ组(P0.01),Ⅲ组n-6极显著高于Ⅰ和Ⅳ组(P0.01),与Ⅱ组差异不显著(P0.05);饲粮n-6/n-3PUFA配比极显著影响皮下脂肪中的MUFA,PUFA,n-3和n-6PUFA(P0.01),而对SFA无显著影响(P0.05),Ⅰ组MUFA极显著高于Ⅱ、Ⅲ和Ⅳ组(P0.01),Ⅱ和Ⅲ组PUFA极显著高于Ⅰ和Ⅳ组(P0.01),Ⅰ和Ⅲ组n-3极显著高于Ⅱ和Ⅳ组(P0.01),Ⅱ组n-6极显著高于Ⅰ和Ⅳ组(P0.01),与Ⅲ组差异不显著(P0.05);3)饲粮n-6/n-3PUFA配比显著影响了北极狐血清中的高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)和补体4(C4)(P0.05),而对血清中的TG、TC和GLU、ⅠgA、ⅠgM、ⅠgG、补体3、TNF和ⅠL-2无显著影响(P0.05),Ⅰ组HDL-C显著高于Ⅱ、Ⅲ和Ⅳ组(P0.05),Ⅰ组LDL-C显著高于Ⅲ和Ⅳ组(P0.05),与Ⅱ组差异不显著(P0.05),Ⅳ组C4显著高于Ⅱ和Ⅲ组(P0.05),与Ⅰ组差异不显著(P0.05)。饲粮n-6/n-3PUFA配比为41时,降低了肝体指数,动员了肌内脂肪和皮下脂肪中不饱和脂肪酸(UFA)含量,利于机体SFA的沉积,降低了血脂中高密度脂蛋白(HDL-C)和低密度脂蛋白(LDL-C)含量,保证了北极狐机体的健康。     

Incorporation of dietary polyunsaturated fatty acids into pork fatty tissues.

The incorporation and elimination rate of dietary PUFA in pork fat was investigated in this study. Experiment 1 examined the incorporation of dietary PUFA into backfat (BF) and into the triglyceride (TG) and phospholipid (PL) fractions of the i.m. fat of the loin. Experiment 2 examined the elimination of PUFA from BF due to withdrawal of PUFA from the diet. In Exp. 1, Piétrain x Seghers Hybrid pigs (70 barrows and 70 gilts averaging 11 wk of age and 30 kg initially) were assigned to five dietary treatments in a 2 x 5 factorial arrangement during a 16-wk feeding period. Pigs received a diet containing about 2.5% tallow (T) for 8, 10, 12, 14, or 16 wk, followed by a diet containing about 15% full-fat soybeans (FFS) for 8, 6, 4, 2, or 0 wk, respectively. Additionally, BF biopsies were taken every 2 wk from eight pigs on the 8-wk FFS dietary treatment, starting from the time pigs were switched to the FFS diet. Linoleic acid [18:2(n-6)], linolenic acid [18:3(n-3)], eicosadienoic acid [20:2(n-6)], arachidonic acid [20:4(n-6)], and PUFA contents in BF increased (P < .01) with time on the FFS diet, but contents of these fatty acids were similar for pigs fed FFS for 6 or 8 wk. The PUFA content of the biopsies rose throughout the FFS treatment; the greatest increase in PUFA occurred during the first 2 wk of feeding FFS. The PUFA content of the TG and PL fractions in i.m. fat of the longissimus muscle tended to increase with time on the FFS diet. The increase was significant (P < .01) in the TG fraction for 18:3(n-3) and in the PL fraction for 20:4(n-6) and 22:6(n-3). In Exp. 2, 11-wk-old pigs (10 barrows and 10 gilts) were fed a FFS-based diet from 11 to 19 wk of age, followed by the T-diet for an additional 8 wk. During the latter period, biopsies were taken every 2 wk. The elimination of PUFA from BF was greatest during the first 2 wk after the dietary change. The PUFA reached the lowest level at the age of 25 wk. These experiments show that the PUFA: saturated fatty acid ratio of BF can be increased from .34, corresponding with a T-based diet, to .55, by feeding a FFS diet for 6 wk before slaughter.     

Duration of feeding linseed diet influences expression of inflammation-related genes and growth performance of growing-finishing barrows

The aim of the study was to investigate the effects of dietary linseed (rich in n-3 PUFA) on expression of inflammation-related genes and on growth performance of growing-finishing barrows. Two isoenergetic and isonitrogenous diets were formulated, one as the basal diet and the other containing 10% linseed. Twenty-four Landrace x Yorkshire barrows weighing 35 +/- 3.7 kg were randomly assigned to 1 of 4 treatment groups, with 6 pigs per group. During the entire experimental period of 90 d, these 4 groups of pigs were first fed the basal diet and then fed the linseed diet for 0, 30, 60, and 90 d before slaughter, respectively. Pig growth; messenger RNA (mRNA) expression of peroxisome proliferator-activated receptor-gamma (PPARgamma), IL-1beta0, IL-6, and tumor necrosis factor-alpha (TNF-alpha); and plasma concentrations of the 3 proinflammatory cytokines were measured and analyzed. Average daily feed intake did not differ among treatment groups (P > 0.05), but ADG (P < 0.05) and G:F (P < 0.01) responded quadratically to the duration of linseed diet feeding, and pigs in the 60-d treatment group had the greatest ADG and G:F. The mRNA expression of PPARgamma in loin muscle and spleen increased linearly (P < 0.01) with the duration of linseed diet feeding, whereas its expression in adipose tissue was not affected (P = 0.095). Tumor necrosis factor-alpha and IL-6 mRNA expression in muscle, adipose, and spleen, as well as serum concentration of TNF-alpha, decreased linearly (P < 0.01) with the duration of linseed diet feeding. Peroxisome proliferator-activated receptor-gamma mRNA abundance was negatively correlated with IL-1beta, IL-6, and TNF-alpha mRNA abundance both in muscle (R(2) = 0.63, P < 0.001) and in spleen (R(2) = 0.69, P < 0.001), and PPARgamma mRNA expression in spleen (R(2) = 0.59, P < 0.01) and muscle (R(2) = 0.52, P < 0.05) was negatively correlated with serum TNF-alpha concentration. There were also significant quadratic relations between ADG and expression of PPARgamma (P < 0.05) and splenic TNF-alpha (P < 0.05). These data suggest that intake of n-3 PUFA from the linseed diet led to significant decreases in the expression of proinflammatory cytokine genes, which may stimulate growth in growing-finishing barrows, at least in part, through a PPARgamma-dependent mechanism.     

Effect of a linseed diet or a sunflower diet on performances, fatty acid composition, lipogenic enzyme activities and stearoyl-CoA-desaturase activity in the pig

The aim of this study was to compare the influence of a high α-linolenic acid (ALA) diet (linseed diet) and a high linoleic acid (LA) diet (sunflower diet) on performances of pigs, on the dietetical quality of their tissues (adipose tissues and muscles), and on the lipogenic potential of these tissues. Growth and carcass performances, and the lipid content of the tissues were not affected by the diet. Feeding the linseed diet increased the content of n-3 PUFA and decreased the LA/ALA ratios in all the tissues, while the sunflower diet led to an increase in the n-6 PUFA contents. Neither the stearoyl-CoA-desaturase and glucose-6-phosphate-dehydrogenase activities nor the β-hydroxyacyl-CoA-dehydrogenase activity were affected by the diet. Acetyl-CoA-carboxylase and fatty acid synthase activities were enhanced with the linseed diet in respectively subcutaneous adipose tissue and intermuscular adipose tissue, while malic enzyme activity was decreased in liver and subcutaneous adipose tissue of pigs fed the linseed diet.     

甜菜碱对生长肥育猪体脂重分配的作用及机理研究

通过48头20～65　kg生长猪和60头60～95　kg肥育猪（Duroc×Landrace×Yorkshire）饲养、屠宰试验和有关生化指标分析，探讨了甜菜碱对生长肥育猪皮下脂肪沉积、胴体脂肪率和肌内脂肪含量的影响及其作用机理。48头生长猪和60头肥育猪分别分成对照和试验2个处理组，每个处理含3个重复，生长猪和肥育猪的试验组分别饲喂含1000　mg／kg和1500　mg／kg甜菜碱的饲粮。结果表明添加甜菜碱，提高了生长猪的日增重13.20％（P＜0.05），降低了料重比7.93％（P＜0.05）；分别降低生长猪和肥育猪的背膘厚14.82％（P＜0.05）和14.93％（P＜0.05）、脂肪率5.76％（P＞0.05）和11.51％（P＜0.05）；分别提高背最长肌肌内粗脂肪含量36.00％（P＜0.05）和17.66％（P＜0.05）。血清生化指标分析表明甜菜碱分别提高生长猪和肥育猪脂肪酶活性10.49％（P＜0.05）和7.50％（P＝0.06），分别提高了血清游离脂肪酸含量20.16％（P＜0.05）和13.43％（P＜0.05），显示甜菜碱加强了猪体脂动员。进一步研究表明，饲喂甜菜碱的生长猪和肥育猪肝脏游离肉碱含量分别提高了20.68％（P＜0.05）和23.53％（P＜0.05），肥育猪背最长肌中酸不溶肉碱含量以及酸不溶肉碱和游离肉碱比例分别提高了48.59％（P＜0.01）和38.24％（P＜0.01），结果揭示甜菜碱似通过提供肉碱合成所必需的甲基以提高生长肥育猪肝脏游离肉碱的含量，促进长链脂肪酸进入肌肉线粒体进行β-氧化，在减少体脂（主要是皮下脂肪）同时，适度增加肌肉脂肪含量，从而发挥着重新分配体脂的作用。     

Influence of extruded linseed on growth, carcass composition, and meat quality of slaughtered pigs at one hundred ten and one hundred sixty kilograms of liveweight

The Western diet is characterized by a high intake of SFA relative to PUFA, and the consumption of n-3 PUFA is decreased relative to n-6 PUFA. Therefore, there has been much interest in recent years in ways to manipulate the fatty acid composition of meat. The objective of this work was to determine the effects of dietary extruded linseed, an n-3 PUFA source, on growth performance, carcass composition, meat quality, and oxidative stability of pigs slaughtered at 111.0 (+/-4.8) kg of BW and 160.0 (+/-9.2) kg of BW. The association of these factors with BW at slaughter was also examined. Forty barrows, 78.1 (+/-1.75) kg of initial BW, were fed a control diet (2.5% sunflower oil) or a linseed diet containing 5% of whole extruded linseed. Both diets contained 170 mg of vitamin E and 250 mug of selenium. Eight pigs from each dietary treatment were slaughtered at 110 kg of BW and the others at 160 kg of BW. There was no dietary effect (P > 0.05) on growth, carcass characteristics, meat quality, or the activity of malic enzyme in LM and backfat. Inclusion of linseed increased (P < 0.05) n-3 PUFA content in both LM and backfat and decreased the n-6:n-3 PUFA ratio from 12 to 4.5 in LM, and from 11 to 3 in backfat. Liveweight at slaughter significantly influenced carcass characteristics, meat quality, total lipid and oxidative stability of LM, malic enzyme activity in adipose tissue, and fatty acid content of LM and backfat. This study shows that the inclusion of linseed in swine diets may improve the fatty acid profile of pork without deleteriously affecting oxidation or color stability. Thus, such a feeding practice may improve human health based on the n-6:n-3 PUFA ratio recommended for the human diet.     

Effect of a high-linolenic acid diet on lipogenic enzyme activities,fatty acid composition,and meat quality in the growing pig

Forty-eight Duroc-cross gilts (40 kg initial BW) were fed a control or a linseed diet containing 60 g of whole crushed linseed/kg. Both diets were supplemented with 150 mg of vitamin E/kg. Eight pigs from each dietary treatment were slaughtered at 20, 60, or 100 d after the start of the experiment. There was no effect (P > 0.05) of diet on growth, carcass characteristics, or foreloin tissue composition. Feeding the linseed diet increased (P < 0.05) the content of n-3 PUFA in plasma, muscle, and adipose tissue, but docosahexaenoic acid was not (P > 0.05) altered by diet. The proportions of n-3 PUFA were highest (P < 0.01) in pigs fed the linseed-diet for 60 d, regardless of tissue (plasma, muscle, or adipose tissue) or lipid (neutral lipids and phospholipids) class. The linseed diet produced a PUFA:saturated fatty acid ratio > or = 0.4 in all groups and tissues, which is close to the recommended value for the entire diet of humans, as well as a robust decrease in the n-6:n-3 ratio. The decrease (P < 0.01) in the percentage of oleic acid in adipose tissue of pigs fed the linseed diet for 60 d could be attributed to a 40% decrease (P < 0.001) in stearoyl-CoA-desaturase activity. Diet did not (P > 0.05) affect the activities of acetyl-CoA-carboxylase, malic enzyme, or glucose-6-phosphate-dehydrogenase in any tissues. Muscle vitamin E content was decreased (P < 0.001) 30% in pigs fed crushed linseed for 60 d, whereas lower (P < 0.001) concentrations of skatole in pork fat were observed in linseed-fed pigs at all slaughter times. Inclusion of linseed (flaxseed) in swine diets is a valid method of improving the nutritional value of pork without deleteriously affecting organoleptic characteristics, oxidation, or color stability.     

The fatty acid composition of muscle fat and subcutaneous adipose tissue of grazing heifers supplemented with plant oil-enriched concentrates

Our objective was to determine the effect of oil supplementation of pasture fed, beef cattle on the fatty acids, particularly CLA and PUFA, of muscle and s.c. adipose tissue. Forty-five Charolais crossbred heifers were blocked on BW and randomly assigned to 1 of 3 dietary regimens in a randomized complete block design (n = 15). The 3 treatments were: unsupplemented grazing (GO), restricted grazing plus a sunflower oil-enriched ration (SO), or restricted grazing plus a linseed oil-enriched ration (LO). Heifers were fed the experimental diets for approximately 158 d. Samples of LM muscle and s.c. adipose tissue were taken postmortem, the muscle fat was separated into neutral lipid and polar lipid (no separation was performed on the s.c. adipose tissue), and the fatty acid profile was determined by GLC. No effect of dietary treatment on carcass weight or total fatty acid concentration (mean 2,571 mg/100 g of muscle) in muscle fat was detected. Heifers offered SO had a greater (P < 0.001) proportion of CLA and C18:1trans-11 (1.90 and 9.35 vs. 1.35 and 6.89 g/100 g of fatty acids, respectively) in neutral lipid of muscle fat compared with those offered LO, which had a greater proportion of CLA and C18:1trans-11 than heifers offered GO (0.78 and 3.37 g/100 g of fatty acids, respectively). Similar effects were observed in the polar lipid and s.c. lipid. The PUFA:SFA ratio was greater in muscle fat and s.c. adipose tissue from supplemented heifers than in those offered GO (P < 0.001). Compared with LO, the PUFA:SFA ratio was greater (P < 0.05) in muscle fat of heifers offered SO, but there was no difference between SO and LO for this ratio in s.c. adipose tissue. The n-6:n-3 PUFA ratio was similar in muscle and s.c. adipose tissue for GO and LO, but it was greater (P < 0.05) for SO. It is concluded that supplementation of pasture-fed cattle with plant oil-enriched concentrates resulted in an increase in beef fat of some fatty acids considered to be of benefit to human health. Concentrates enriched with sunflower oil were more effective in increasing the CLA concentration, whereas linseed oil-enriched concentrates resulted in a more favorable n-6:n-3 PUFA ratio. The relevance to human health of the associated increase in C18:1trans-11 merits investigation.     

饲粮类型和肥育后期不添加维生素和微量矿物元素对猪生长性能、胴体和肌肉品质、粪中矿物元素排泄的影响

本研究共开展两个试验,探讨饲粮类型和不添加维生素和微量矿物元素对猪肥育后期生长性能、胴体和肌肉品质、粪中微量矿物元素排泄的影响。在试验1中,选用128头平均体重(78.5±4.6)kg的肥育猪,根据体重和性别分成4组,每组4圈(重复),每个重复8头猪。四组试验猪的试验处理为2×2因子设计,即两种类型(玉米-豆粕型和玉米-杂粕型)饲粮和添加或不添加维生素/微量矿物元素预混料。在试验2中,选用112头平均体重(90.3±6.3)kg的肥育猪,根据体重和性别分成4组,每组4圈(重复),每个重复7头猪。试验处理同试验1。结果显示,在79~110kg肥育期中(试验1),采食玉米-豆粕型饲粮的猪的增重速度和采食量显著高于采食玉米-杂粕型饲粮的猪(P<0.01或0.05)。在90~105kg肥育期中(试验2),采食玉米-豆粕型饲粮的猪的增重速度仍然高于采食玉米-杂粕型饲粮的猪(P<0.05)。但是,维生素和微量矿物元素添加与否对生长性能无显著影响(P>0.05)。饲粮类型和不添加维生素和微量矿物元素对胴体和肌肉品质均无显著影响(P>0.05)。粪中微量矿物元素含量不受饲粮类型的影响(P>0.05),但不添加维生素和微量矿物元素时,粪中铜、铁、锰的含量显著降低(P<0.01),粪中锌含量也有降低的趋势(P>0.05)。对于生长性能、胴体和肌肉品质以及微量矿物元素排泄量,饲粮类型×维生素/微量矿物元素预混料的交互作用不显著(P>0.05)。结果表明,在猪的肥育后期(最后约25~40d),在玉米-豆粕型和玉米-杂粕型饲粮中可不添加维生素和微量矿物元素,从而可降低饲料成本和减少微量矿物元素的排泄。     

Effects of dietary energy density on plasma glucose and lipid profile,morphological aspects and chemical characteristics of adipose tissue in finishing pigs

Peroxisome proliferator-activated receptor-γ (PPAR-γ) plays a pivotal role in controlling adipogenesis.We hypothesized that changes in dietary energy density might alter fat deposition in finishing pigs via modulation of the expression of PPAR-γ.To test this hypothesis,thirty female finishing pigs were fed diets containing low (LD),medium (MD) or high (HD) energy density.Blood samples were collected on day 53,and then the pigs were sacrificed to collect samples of the dorsal subcutaneous (ST),abdominal (AT) and mesenteric (MT) adipose tissue.Compared with pigs fed the MD diet,malate dehydrogenase activity was increased in the ST and MT of pigs fed the HD diet,while activity was decreased in the MT of pigs fed the LD diet (P0.05).Glucose-6-phosphate dehydrogenase activity was increased in all three fat depots of pigs fed the HD diet (P0.05) in comparison with pigs fed the MD diet.Both HD and LD diets increased the size of the adipocytes in the AT and MT (P0.05).Pigs fed the HD diet had a higher cell proliferation index in the ST compared with pigs fed the other two diets (P0.05).Compared with pigs fed the MD diet,a decreased apoptosis index was seen in the ST of pigs fed the HD diet,and in the AT of pigs fed the LD diet,as well as in the MT of both HD and LD fed pigs (P0.05).PPAR-γ positive percentage was elevated in the ST and MT of HD fed pigs compared with pigs fed the MD and LD diets,while it was decreased in the ST of LD compared with MD fed pigs (P0.05).These results suggest that dietary energy density may regulate fat deposition in finishing pigs.It is possible that feeding a high energy diet may induce fat deposition via up-regulation of PPAR-γ expression.     

The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle.

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.