鸭胚骨骼肌不同组织Myf6基因表达的发育性变化研究

为研究Myf6基因对鸭肌肉发育的影响,本试验利用实时荧光定量PCR绝对定量技术检测Myf6基因在高邮鸭和金定鸭胚胎期第13、17、21、25、27天及出生后7日龄胸肌、腿肌发育过程中的表达量。结果显示,Myf6基因在2个品种的胸肌和腿肌中均有表达,在不同品种同一肌肉组织中的表达变化规律一致,而在不同肌肉组织中的表达模式不同,其中在胸肌组织中21胚龄时表达量最高,随后表达量下降,维持相对较高表达水平;在腿肌组织中13胚龄时表达量较高,17胚龄时达到最高,随后表达量有所降低,并在21胚龄后急速下降至极低水平,但其表达在胚胎期后期(27胚龄)及初生期(7日龄)又有缓慢上升趋势。上述结果表明,Myf6基因参与了胸、腿肌组织的发育,在胸、腿肌中表达模式不同,推测Myf6基因在胸、腿肌中的调控存在差异,可能与其胸、腿肌不同肌纤维的发育与分化有关。     

巨型玫瑰冠鸡ADSL基因表达及其与IMP的相关分析

为探讨腺苷琥珀酸裂解酶(ADSL)基因在巨型玫瑰冠鸡胸肌与腿肌中的表达以及与肌苷酸(IMP)的关系,研究ADSL基因对巨型玫瑰冠鸡肌肉中鲜味物质的影响作用。本试验采集巨型玫瑰冠鸡与良凤花鸡在不同周龄(2、4、6、8、10、12周龄)的胸肌、腿肌组织样品共96份,采用实时荧光定量PCR方法对巨型玫瑰冠鸡与良凤花鸡不同生长阶段组织中ADSL基因表达量进行检测,并采用高效液相色谱法测定了两种鸡12周龄的胸肌与腿肌的IMP含量。结果表明:巨型玫瑰冠鸡与良凤花鸡的胸肌中ADSL基因表达的变化趋势基本一致,2周龄、4周龄时巨型玫瑰冠鸡的表达量远高于良凤花鸡(P0.01),10周龄时两品种间表达量呈差异显著水平(P0.05);两品种鸡腿肌中ADSL基因的表达均呈波动性变化,且都在8周龄时最低、10周龄时最高;ADSL基因表达量与肌肉中的IMP含量显著正相关。因此,可将ADSL基因作为巨型玫瑰冠鸡肌肉中鲜味物质性状选育的候选基因。     

“花山麻鸡”CPT1A基因时空表达规律研究

试验旨在阐明"花山麻鸡"CPT1A基因的组织表达和时序表达规律,以胚胎期到上市日龄的"花山麻鸡"为试验材料,在不同发育时间点采集胸肌、腿肌、心脏、肝脏组织样品,利用实时荧光定量方法分析CPT1A基因在不同组织不同发育阶段表达规律。在相同发育阶段不同组织差异表达结果显示:在胚胎期(9、12、16日胚龄)和上市日龄(9周龄),CPT1A基因在肝脏的表达量显著高于在心脏、胸肌和腿肌的表达量,在出生后1日龄,CPT1A在心脏表达量最高,1周龄时,CPTA在肝脏的表达量最低;5周龄时,CPT1A在腿肌的表达量最高;7周龄时,CPT1A在腿肌和肝脏的表达量显著高于胸肌和心脏。在同一组织不同发育阶段差异表达结果显示,CPT1A在胸肌、腿肌、肝脏和心脏不同发育阶段表达规律与表达量是不同的。研究表明CPT1A基因在胸肌、腿肌、肝脏和心脏相同发育阶段表达量不同,CPT1A基因在胸肌、腿肌、肝脏和心脏织不同发育阶段表达规律与表达量不同。     

金定鸭胚胎期骨骼肌发育模式及MRFs家族基因表达变化研究

MRFs (Myogenic regulatory factors,MRFs)家族包括肌分化因子MyoD、肌细胞生成素(myogenin)、生肌决定因子Myf5和Myf6,它们参与肌肉发生发育的各个环节.研究采用Real-time PCR方法研究了金定鸭胚胎期13、17、21、25和27日胚龄MRFs家族基因在骨骼肌中的表达变化,并分析其表达变化与胚重、骨骼肌发育的相关性.金定鸭胚重及骨骼肌重发育模式显示胚重在胚胎期呈持续增加趋势,但胸肌在胚胎中后期显示出较腿肌滞后的增重变化.MRFs家族基因在胚胎期骨骼肌中均能检测到表达,MyoD mRNA在21日胚龄前腿肌中的表达量高于胸肌,而在胚胎发育后期(25及27日胚龄)胸肌中表达量渐渐高于腿肌.胸、腿肌中myogenin mRNA的表达与胚重、胸、腿肌发育重量变化均呈强的负线性相关.上述研究结果首次揭示了鸭胚胎期骨骼肌中MRFs家族基因表达具有显著的时空性,推测MyoD mRNA在胸、腿肌中的表达变化可能与胸、腿肌增重表型差异有关,研究结果为进一步深入研究MRFs家族基因在胚胎期骨骼肌发生过程及其调控机理中的功能提供一定的理论依据.     

放养模式下不同鸡种屠宰性能、肉质特性及相关基因表达规律研究

研究以大恒699优质肉鸡和沐川黑鸡为素材,于3个日龄点进行屠宰性能和肉质特性的分析,同时采用RT-PCR法对ADSL基因和H-FABP基因表达量进行测定,分析基因表达规律及其与肉质性状之间的相关性。结果:1屠宰性能:大恒699在120日龄时屠宰率最高,90日龄时胸肌率和腿肌率最佳;沐川黑鸡90日龄时胸肌率、腿肌率偏低,120日龄时屠宰率、胸肌率和腿肌率均较高。2肉质特性:大恒699与沐川黑鸡肌苷酸(IMP)含量均为先降后升的趋势,品种间差异不显著(P0.05)。大恒699肌内脂肪(IMF)含量随日龄增加而增加;沐川黑鸡IMF含量120日龄150日龄90日龄,大恒699 IMF含量略高于沐川黑鸡。3基因表达规律及与肉质性状相关性:大恒699和沐川黑鸡ADSL基因相对表达量90日龄时高于120和150日龄,大恒699差异显著(P0.05)。ADSL基因相对表达量均与IMP含量显著相关(P0.05),基因表达量的增减趋势与IMP含量的变化趋势一致。两个品种H-FABP基因相对表达量日龄间差异不显著(P0.05),90和150日龄H-FABP基因相对表达量与IMF含量显著或极显著负相关(P0.05或P0.01),而120日龄H-FABP基因相对表达量与IMF含量不相关(P0.05)。     

种鸡及子代肉仔鸡饲粮添加外源肌苷酸对子代肉仔鸡生长性能、肉品质及相关基因表达的影响

本试验旨在研究种鸡及子代肉仔鸡饲粮添加外源肌苷酸(IMP)对子代肉仔鸡生长性能、肉品质及相关基因表达的影响。选取遗传背景相同、体重相近、产蛋率达到5%的20周龄健康爱拔益加(AA)种鸡864羽,随机分为2组,每组6个重复,每个重复72羽。对照组饲喂基础饲粮,试验组在基础饲粮中添加0.5%肌苷酸,试验期30 d。试验结束前1周,母鸡产蛋率到达高峰期,连续收集7 d种蛋,共3 700枚种蛋孵化,孵化结束后,依据母代分组情况,选取孵化所得1日龄健康子代肉仔鸡3 000羽,分成4组,分别记为II(母代饲喂基础饲粮+0.5%肌苷酸,子代饲喂基础饲粮+0.5%肌苷酸)、IN(母代饲喂基础饲粮+0.5%肌苷酸,子代饲喂基础饲粮)、NI(母代饲喂基础饲粮,子代饲喂基础饲粮+0.5%肌苷酸)和NN组(母代饲喂基础饲粮,子代饲喂基础饲粮),每组6个重复,每个重复125羽。试验期42 d。结果表明:1)与NN组相比,II、IN和NI组子代肉仔鸡的平均日增重、平均日采食量和料重比均无显著差异(P0.05)。2)与NN组相比,II、IN和NI组子代肉仔鸡胸肌率和腿肌率均无显著差异(P0.05);II组腹脂率显著高于NI组(P0.05)。3)与NN组相比,II、IN和NI组子代肉仔鸡胸肌、腿肌的红度(a*)和黄度(b*)值均无显著差异(P0.05),II组胸肌的亮度(L*)值显著降低(P0.05);IN和NI组胸肌和腿肌pH45 min显著提高(P0.05),IN和NI组胸肌pH24 h显著提高(P0.05),II、IN和NI组腿肌pH24 h显著升高(P0.05)。4)与NN组相比,II、IN和NI组21和42日龄胸肌和腿肌的谷氨酰胺磷酸核糖焦磷酸酰胺转移酶(GPAT)基因相对表达量没有显著差异(P0.05),21日龄NI组胸肌和IN组腿肌的腺苷琥珀酸裂解酶(ADSL)基因相对表达量显著提高(P0.05),42日龄II和IN组胸肌的ADSL基因相对表达量显著提高(P0.05)。以上结果提示,种鸡及子代肉仔鸡饲粮添加外源肌苷酸对子代肉仔鸡生长性能、屠宰性能无显著影响;能够提高肌肉pH,降低胸肌L*值,提高胸肌ADSL基因表达量,在一定程度上能够提高子代肉仔鸡肉品质。     

鸡胚胎期和出生后Pax3基因时空表达规律的研究

为探讨鸡Pax3基因在胚胎阶段以及不同生长阶段的时空表达规律,试验选取同一批鸡胚(8、16、20 d和21 d)以及2、4、6、8、10、12周龄的如皋鸡各6只,公、母各半,采用SYBR GreenⅠ实时荧光定量PCR技术分析了Pax3基因在胸肌、腿肌中的表达规律。结果表明:胸肌和腿肌组织中公、母鸡表达水平变化趋势一致,无性别效应;在胸肌组织中,Pax3基因在8 d的鸡胚中表达水平最高,随后降到最低,出雏前缓慢上升,出雏后随着周龄的增加表达水平保持在较低状态。但在腿肌组织中,Pax3基因的表达高峰在出雏前(20 d和21 d),出雏后随周龄的增加表达量持续降低,并保持在较低的水平。表明Pax3基因表达存在组织特异性,且集中在胚胎期大量表达,出雏后表达水平较低,揭示该基因可能对鸡肌纤维生长发育存在调控作用。     

鸭胚胎及其组织器官生长发育规律的研究

为了研究高邮鸭胚胎及其重要组织器官的生长发育情况,测定了高邮鸭胚胎的胚重、胚长、肝脏重、胸肌重及腿肌重,并对其进行分析.结果表明:随着胚龄的增加,鸭胚胎的胚重、肝脏、胸肌和腿肌性状的测定值由慢到快逐渐增大,而胚长的累积生长趋势较为平缓.鸭胚胎的胚重、肝脏的绝对生长速度随着胚龄的增加而增加,胚长的生长速度较为平缓,17胚龄达到高峰(0.59 cm/d),然后缓慢下降;胸肌的生长速度较为缓慢,17胚龄最高(0.06 mg/d),然后逐渐下降;腿肌的绝对生长速度随着胚龄的增加而缓慢增加,但在27胚龄后有所下降.鸭胚胎的所有性状的相对生长都表现为前期强后期弱的趋势.不同孵化阶段鸭胚胎的各组织器官与整体的生长速度不一致,13～27胚龄期间,肝脏、腿肌为晚熟部位,胸肌为早熟部位.本研究结果为鸭胚胎的相关研究提供了基础理论依据.     

鸭发育早期骨骼肌NFATc3 mRNA差异表达及其与生长性状的相关性研究

为研究不同品种鸭胚胎期和出雏早期骨骼肌中NFATc3基因mRNA表达规律及其与生长发育的相关性,运用荧光绝对定量PCR技术检测了生长速度差异较大的高邮鸭和金定鸭13、17、21、25、27胚龄和7日龄胸肌和腿肌中NFATc3 mRNA的表达水平。结果表明胸肌和腿肌NFATc3 mRNA在两鸭品种中均具有相似的表达模式,不存在品种效应,胸肌和腿肌NFATc3 mRNA的表达均是13胚龄时表达量最高,显著高于其它各胚龄或日龄(P0.05);相关性分析结果表明两个品种鸭骨骼肌NFATc3 mRNA表达量与其组织重、体重均呈极显著负相关(P0.01),而与肌肉组织中IGF-Ⅰm RNA的表达量呈极显著正相关(P0.01)。鸭骨骼肌中NFATc3主要在早期的肌纤维生成中起作用,与IGF-Ⅰ可能共同参与了对骨骼肌生长发育的调节。     

高邮鸭和金定鸭胸肌早期发育及MyoD1基因表达分析

 
采用qPCR分析生肌调节因子MyoD1基因在高邮鸭和金定鸭胚胎期及初生早期(13、17、21、25、27胚龄和出雏后7日龄)胸肌发育中的表达模式以及与胚胎和胸肌发育的相关性。结果表明,MyoD1 mRNA在两个品种鸭胸肌早期发育中表现出一致的表达规律,均呈“波浪形”,在13胚龄时表达量相对较高,17胚龄时下降,21胚龄时上升到最高,随后下降,出雏后又维持较高水平;品种间比较结果显示除了在25胚龄时金定鸭胸肌中MyoD1 mRNA表达量稍低于高邮鸭,在其他所检测的胚龄/日龄中,金定鸭胸肌中MyoD1 mRNA表达量均高于高邮鸭胸肌中的表达量(P>0.05);高邮鸭胸肌MyoD1 mRNA表达与胚胎和胸肌发育无显著相关性,而金定鸭胸肌中MyoD1 mRNA的表达与其胚胎和胸肌发育呈强负相关(P胚重=0.048;P胸肌重=0.006)。MyoD1基因参与鸭胚胎期及出雏早期胸肌的发育,胸肌中MyoD1基因表达分析研究为进一步深入研究MyoD1基因在胚胎期胸肌发生过程及其调控机理中的功能提供一定的理论依据     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.