Contents of the glucose transporters GLUT1 and GLUT4 in oxidative and glycolytic muscles of goat kids and adult goats

The objective of this study was to elucidate, whether the impaired insulin sensitivity with regard to glucose utilisation in ruminating goats compared with suckling goat kids may be due to a reduced expression of the glucose transporters GLUT1 and GLUT4 in skeletal muscle. Muscle samples were removed from red, oxidative muscles (M. masseter, diaphragm) and white, glycolytic muscles (M. longissimus dorsi, and M. semitendinosus) of five goat kids fed with milk exchanger and nine adult goats of different stages of life. Samples were analysed for their GLUT1 and GLUT4 contents. The muscles were characterised metabolically by measuring the activities of isocitrate dehydrogenase (ICDH) and of lactate dehydrogenase. In all four analysed muscles the GLUT4 contents of adult goats were significantly (p < 0.05) lower than in goat kids. Significant differences concerning the GLUT4 contents in skeletal muscles were not detected in adult goats of different stages of life. The GLUT1 contents differed to a lower extend between goat kids and adult goats. The results of this investigation indicate that the impaired insulin sensitivity of adult compared with suckling ruminants is accompanied by or leads to a decreased GLUT4 expression.     

长期饲喂高精料日粮对泌乳期山羊血液生化参数及组织中糖代谢相关基因表达的影响

为了研究长期饲喂高精料日粮对泌乳期山羊血液生化指标和糖代谢的影响,选择8只安装永久性瘤胃瘘管的健康经产泌乳中期山羊,分别饲喂精粗比为40∶60 (low concentrate, LC,n=4) 和60∶40 (high concentrate, HC,n=4)的日粮。实验期共8周,实验期间采集瘤胃液,血液;实验结束时采集肝脏,肌肉,脂肪组织置于液氮速冻后于-70℃保存待测。结果显示,饲喂高精料日粮2周后山羊瘤胃液pH显著降低,采食后瘤胃液pH持续低于5.8超过3 h,8周后瘤胃液pH升高维持在6.0以上,但仍低于LC组山羊。与LC组山羊相比较,HC组山羊血液中葡萄糖、游离脂肪酸含量均升高(P<0.05,P=0.071),谷草转氨酶含量有上升的趋势(0.05相似文献   

不同高精料耐受时间对泌乳期山羊肝脏糖脂代谢的影响

为了研究饲喂高精料日粮对泌乳期山羊肝脏糖脂代谢的影响,试验选用16只健康经产泌乳中期关中奶山羊,随机分为3组,低精料组(LC, n=5)、长期高精料组(HL, n=7)和短期高精料组(HS, n=4)。实验结束后采集血液和肝脏组织。结果显示,与LC组相比,HL和HS组奶山羊血糖和肝糖原水平显著升高(P<0.05),血液中甘油三酯(TG)水平显著降低(P<0.05),胆固醇(Tch)含量没有显著变化(P>0.05);HS组山羊肝脏TG和Tch水平显著增加(P<0.05),HL组无显著变化 (P>0.05)。HL组肝脏中丙酮酸羧化酶(PC)和葡萄糖转运蛋白2(GLUT2)mRNA表达水平显著上调;HS组肝脏PC、固醇调节元件结合蛋白1(SREBP1)、硬脂酰辅酶A去饱和酶(SCD)、二酰基甘油酰基转移酶(DGAT)和3-羟基-3-甲基戊二酰辅酶A还原酶(HMGCR) mRNA表达水平显著升高(P<0.05),SREBP-2有升高的趋势(P=0.76),肉碱棕榈酰转移酶-1(CPT-1)和胆固醇7α-羟化酶(CYP7α1)mRNA表达显著下降(P<0.05);线粒体型磷酸烯醇式丙酮酸羧激酶(PCK2)蛋白表达水平显著升高(P<0.05)。以上结果表明,短期饲喂高精料日粮能增强肝脏糖异生能力,促进肝脏胆固醇和脂肪合成;而长期饲喂高精料日粮能增强肝脏糖异生作用,但对胆固醇和脂肪代谢相关基因的表达没有影响。     

鸡肝细胞中C/EBPα基因的敲低及对糖脂代谢相关基因表达的影响

C/EBPα即CCAAT/增强子结合蛋白α基因,其编码的CCAAT/增强子结合蛋白是重要的转录调控因子,在细胞的分化和代谢过程中发挥着重要的调节作用。试验利用RNAi来敲低鸡LMH细胞系中C/EBPα基因的表达,以研究C/EBPα基因影响脂肪代谢的机制。根据鸡C/EBPα基因的mRNA序列,设计3对siRNA,用RNAi干扰技术来敲低鸡LMH细胞中的C/EBPα基因表达,然后用荧光定量PCR检测C/EBPα基因的表达情况,发现其中的C/EBPα-siRNA-161能够显著降低C/EBPα基因的表达;并将C/EBPα-siRNA-161转染LHM细胞后48 h后,利用荧光定量PCR检测LMH细胞中糖脂代谢相关基因(PCK1、SCD、GLUT2、PPARγ、INS、G6PC、IGF1、IGF2、INSR、STAT3)的表达,发现在LMH细胞中PCK1、G6PC、GLUT2基因的mRNA表达量下降,结果表明C/EBPα基因能影响糖代谢相关基因G6PC、GLUT2、甘油异生相关基因PCK1的表达,证实了C/EBPα基因对鸡肝细胞中的糖脂代谢具有调控作用,通过调控C/EBPα基因的表达将影响糖吸收及甘油异生。     

Endocrine,blood metabolite,and meat quality changes in goats as influenced by short-term,preslaughter stress

The purpose of this study was to determine the effects of short-term, preslaughter stress on physiological responses and meat quality in goats of different age groups. The goats (n = 28) were classified into young (6 to 12 mo of age) and old (24 to 30 mo of age) groups, feed deprived overnight, and slaughtered at three different times (replicates). On each slaughter day, goats were either subjected to a 2-h transportation stressor (TS) or remained unstressed in holding pens (NS) before slaughter. Blood samples were collected via jugular venipuncture from TS and NS goats at 2, 1, and 0 h before slaughter. Muscle glycogen and pH were measured on samples from longissimus muscle (LM) collected at 15 min and 24 h postmortem, and instrumental measures of meat color were obtained on the LM after a 24-h chilling period at 4 degrees C. The TS goats had higher plasma cortisol (P < 0.01) and glucose (P < 0.05) concentrations than NS goats. The rates of increase in plasma cortisol, glucose, and nonesterified fatty acid concentrations were greater in TS than in NS goats (stressor treatment x blood sampling time, P < 0.01). Muscle glycogen concentrations were greater (P < 0.05) in NS than in TS goats and higher (P < 0.01) in old vs. young goats; however, pH measured at 15 min and 24 h postmortem was not (P > 0.05) influenced by stressor treatment. Water-holding capacity of meat was not (P > 0.05) influenced by stressor treatment. Older goats had lower (P < 0.01) L* values and greater (P < 0.01) a* and chroma values than the younger goats. The a* and chroma values of loin cuts from young goat carcasses were lower in the TS than NS treatment groups, but this effect was absent in the old goat carcasses (stressor treatment x age, P < 0.05). Cooking loss percentages and shear force values for loin chops aged for 7 d were not (P < 0.05) affected by stressor treatment; however, old goats produced tougher (P < 0.01) loin chops than young goats. These results indicate that short-term preslaughter transport can cause noticeable changes in stress responses and muscle metabolism in goats.     

猪A-FABP基因真核表达载体的构建及其组织表达

本实验以长白猪背最长肌为实验材料,进行组织RNA的提取及A-FABP基因的克隆,构建p EGFPN1-A-FABP真核表达载体,并通过脂质体转染成纤维细胞,48 h观察荧光表达。同时应用荧光定量PCR法检测猪7种不同组织(心脏、肝脏、脾脏、肺脏、肾脏、背最长肌、腿肌)中A-FABP基因的差异表达。结果表明:成功构建p EGFP-N1-A-FABP融合表达载体,并在细胞中表达绿色荧光蛋白;A-FABP基因在7种组织中均有表达,其中背最长肌和腿肌中A-FABP基因的表达量最高,与其他组织相比差异极显著(P0.01),而脾脏和肾脏中的表达量相对于心脏、肝脏和肺脏差异显著(P0.05),而A-FABP基因表达量在心脏、肝脏和肺脏中差异不显著(P0.05)。表明该基因能够在真核载体和细胞中表达,并且在猪不同组织的表达具有差异性。     

九龙牦牛PPARγ基因的克隆及其表达谱分析

根据普通牛(Bos tarus)过氧化物酶体增殖物激活受体γ(PPARγ)基因序列设计引物,用成年九龙牦牛(Bos grunniens)脂肪组织总RNA,经RT-PCR扩增获得了PPARγ基因序列(GenBank登陆号:GU061328),其中cDNA的ORF为1 428 bp,编码475个氨基酸,与普通牛PPARγ氨基酸的同源性达99%,有2个氨基酸发生突变。利用半定量RT-PCR分析九龙牦牛PPARγ基因的mRNA表达特性。结果表明:在脂肪、背最长肌、心、肝、肾、脾和肺脏中均检测到PPARγ基因的表达,并且在脂肪组织中表达量极显著高于其他组织(P0.01),在肝脏和脾脏中亦有较高表达。PPARγ基因在背最长肌中的表达5.5岁九龙牦牛显著高于0.5、3.5岁和9岁以上,其表达与背最长肌的肌内脂肪含量未见显著相关性。     

Acute immobilization stress in prone position in susceptible Pietrain and resistant Duroc pigs. II. Glycolytic metabolism in Piettrain and Duroc skeletal muscle and liver

Duroc (D) and Pietrain (P) pigs were used to study the effect of acute immobilization stress on carbohydrate metabolism. Changes in the activities of several glycolytic enzymes and the content of glycogen in longissimus dorsi muscle (LDM), glycogen content in the liver and glucose level in plasma were observed. The glycogen level in LDM of pigs was about five times higher in P pigs compared with D ones. The immobilization stress of 15 min caused a decrease of glycogen LDM content by 27% in D and by 44% in P pigs. In the liver, these changes were 75% in P pigs, but in D pigs the glycogen content was lowered during the time of experiment by 37% (control versus 60 min stress). Plasma glucose level was elevated by 118% in D and by 50.5% in P pigs after 15 min of immobilization stress. The activities of the glycolytic enzymes investigated changed in different way in LDM: the PGluM decreased by 20% in D and by 19% in P pigs; the GPI by 8.5% in both strains of pigs; the PFK and PK were higher in D than in P pigs (some statistically significant differences between PK activities of control and 15‐, 30‐ and 60‐min‐stressed animals); the ALD activity was similar in both investigated strains of pigs and LDH was lower in D than in P pigs. It can be assumed that the changes led to the new homeostasis connected with the stress to which the pigs were subjected.     

Changes in gene expression of glucose transporters in lactating and nonlactating cows

Glucose delivery and uptake by the mammary gland are a rate-limiting step in milk synthesis. It is thought that insulin-independent glucose uptake decreases in tissues, except for the mammary gland, and insulin resistance in the whole body increases following the onset of lactation. To study glucose metabolism in peak-, late-, and nonlactating cows, the expression of erythrocyte-type glucose transporter (GLUT1) and the insulin-responsive glucose transporter (GLUT4) in the mammary gland, adipose tissue, and muscle were assessed by Western blotting and real-time PCR. Our results demonstrated that the mammary gland of lactating cows expressed a large amount of GLUT1, whereas the mammary gland of nonlactating cows did not (P < 0.05). On the other hand, adipose tissue of late and nonlactating cows expressed a large amount of GLUT1, whereas the adipose tissue of peak-lactating cows did not (P < 0.05). There were no significant differences in the abundance of GLUT4 mRNA in adipose tissue and muscle, whereas GLUT4 mRNA was not detected in the mammary gland. The plasma insulin concentration was greater (P < 0.05) in nonlactating cows than in peak- and late-lactating cows. The results of the present study indicate that in lactation, GLUT1 expression in the mammary gland and adipose tissue is a major factor for insulin-independent glucose metabolism, and the expression of GLUT4 in muscle and adipose tissue is not an important factor in insulin resistance in lactation; however, the plasma insulin concentration may play a role in insulin-dependent glucose metabolism. Factors other than GLUT4 may be involved in insulin resistance.     

Characterisation of glucose transporter (GLUT) gene expression in broiler chickens

1. Glucose transporter (GLUT) proteins, one of which is the major insulin-responsive transporter GLUT4, play a crucial role in cellular glucose uptake and glucose homeostasis in mammals. The aim of this study was to identify the extent of mRNA expression of GLUT1, GLUT2, GLUT3 and GLUT8 in chickens intrinsically lacking GLUT4. 2. GLUT1 mRNA was detected in most tissues of 3-week-old broiler chickens, with the highest expression measured in brain and adipose tissue. GLUT2 was expressed only in the liver and kidney. GLUT3 was highly expressed in the brain. GLUT8 was expressed ubiquitously, with expression in kidney and adipose tissue relatively higher than that of other tissues. 3. Expression levels of GLUT isoforms 1, 3 and 8 in skeletal muscle tissue were very low compared to the other tissues tested. 4. [3H]Cytochalasin B binding assays on tissue from 3-week-old chickens showed that the number of cytochalasin B binding sites in skeletal muscle plasma membranes was higher than in liver plasma membranes. These results suggest that GLUT proteins and/or GLUT-like proteins that bind cytochalasin B are expressed in chicken skeletal muscles. 5. It is proposed that GLUT expression and glucose transport in chicken tissues are regulated in a manner different from that in mammals.     

不同品种猪在不同生理阶段骨骼肌葡萄糖转运体和胰岛素受体表达的发育性变化

本试验旨在研究不同品种猪在不同生理阶段骨骼肌葡萄糖转运载体(GLUT)1、GLUT4和胰岛素受体(IR)mRNA表达的发育规律.试验以1、7、30、60、90和150日龄蓝塘和长白两品种猪背最长肌、半膜肌和半腱肌组织样品cDNA为模板,采用实时荧光半定量PCR的方法,检测猪GLUT1和GLUT4 mRNA在不同骨骼肌中的表达模式.结果显示:1)1～ 150日龄蓝塘和长白猪背最长肌、半膜肌和半腱肌GLUT1 mRNA表达存在相似的发育变化规律,在1日龄时相对表达丰度最高.2)1 ～ 150日龄蓝塘和长白猪半膜肌和半腱肌GLUT4 mRNA相对表达丰度随日龄呈波形式变化,变化速度和程度存在品种差异.1日龄和150日龄时蓝塘猪背最长肌GLUT4mRNA相对表达丰度低于同日龄长白猪(P>0.05),而在其余日龄时高于同日龄长白猪(P>0.05).3)蓝塘和长白猪背最长肌、半膜肌和半腱肌IR mRNA相对表达丰度在1和30日龄时表现出较高水平,而在7、60、90和150日龄时无显著差异(P>0.05);同日龄蓝塘和长白猪之间IR mRNA相对表达丰度无显著性差异(P>0.05).结果表明:猪骨骼肌GLUT1 mRNA的表达在不同生理阶段存在差异,猪骨骼肌GLUT4 mRNA的表达在不同品种和生理阶段存在显著差异,且其与IR mRNA的表达相关性较弱,无明显规律.     

Effect of nutrient intake on intramuscular glucose metabolism during the early growth stage in cross‐bred steers (Japanese Black male × Holstein female)

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism‐related genes in skeletal muscle of cross‐bred cattle. From 1.5 to 5 months of age, group H (n = 7) animals were intensively fed a high‐protein and low‐fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n = 7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high‐nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real‐time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3‐kinase (PI‐3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin‐independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin‐dependently mediated glucose uptake in LT of cattle.     

Study on the Intervention Effect and Mechanism on Insulin Resistant Mice of Total Flavone from Melastoma dodecandrum Lour.

This experiment was conducted to explore the intervention effect and mechanism on insulin resistance (IR) mice of total flavonoids from Melastoma dodecandrum Lour.(TFMD).The model of IR mice was established by intragastric administration of high-fat emulsion,while 600,300 and 150 mg/kg TFMD were administered once daily for 30 days.After the end of the experiment the mices' fasting blood glucose (FBG),fasting serum insulin (FINS),serum total cholesterol(TC),triglyceride (TG),high density lipoprotein(HDL) were determined.The mRNA expression level of liver insulin receptor(InsR),fat peroxisome proliferator-activated receptor-γ(PPAR-γ),and glucose transporter 4 gene (GLUT4) in skeletal muscle were detected by Real-time quantative PCR,and the protein levels were detected by immunohistoche mical method.The results showed that TDMF could reduce the body weight of IR mice,decrease the level of serum FBG,FINS and HOMA-IR,increase the level of ISI,decrease the content of serum TG,TC and LDL,and increase the content of HDL(P<0.01,P<0.05);And the mRNA expression of INSR,PPAR-γ in liver and GLUT4 in skeletal muscle of IR mice were increased(P<0.01,P<0.05),and the protein expression level of InsR,PPAR-γ in liver and GLUT4 in skeletal muscle of IR mice were increased(P<0.01,P<0.05).The results confirmed that the TFMD could relieve experimental insulin resistance in mice,and the activity was related to the regulation of glucose and lipid metabolism and the enhancement of insulin sensitivity.     

地菍总黄酮对胰岛素抵抗小鼠的干预作用及机制研究

本研究旨在探讨地菍总黄酮（TFMD）对胰岛素抵抗（IR）小鼠的干预作用及其机制。试验以灌胃高脂乳剂建立胰岛素抵抗小鼠模型，同时灌胃给予地菍总黄酮混悬液（高剂量（600 mg/kg）、中剂量（300 mg/kg）及低剂量（150 mg/kg））进行治疗，治疗周期为30 d。试验结束后测定小鼠血清中空腹血清胰岛素（FINS）、空腹血糖（FBG）、胰岛素抵抗指数（HOMA-IR）、胰岛素敏感指数（ISI）、血清甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白（LDL）及高密度脂蛋白（HDL）水平；利用实时荧光定量PCR法检测各组小鼠肝脏中胰岛素受体（InsR）、过氧化物酶体增殖物激活受体-γ（PPAR-γ）及骨骼肌中葡萄糖转运体4（GLUT4）的mRNA表达水平；利用免疫组化技术检测各组小鼠肝脏中InsR、PPAR-γ和骨骼肌中GLUT4的蛋白表达水平。结果显示，与模型组相比，地菍总黄酮能降低IR小鼠的体重，降低血清FBG、FINS及HOMA-IR水平，升高ISI水平（P<0.01，P<0.05）；降低血清TG、TC及LDL含量，升高HDL含量（P<0.01，P<0.05）；同时提高IR小鼠肝脏中InsR、PPAR-γ及骨骼肌中GLUT4的mRNA表达量，提高小鼠肝脏InsR、PPAR-γ及骨骼肌中GLUT4的蛋白表达水平（P<0.01，P<0.05）。以上试验结果证实，地菍总黄酮能有效缓解小鼠试验性胰岛素抵抗症状，该活性与调节糖脂代谢、增强胰岛素敏感性有关。     

肉碱棕榈酰转移酶基因在绵羊和山羊不同肌肉组织中的表达分析

采用实时荧光定量PCR方法比较分析了肉碱棕榈酰转移酶(carnitine palmitoyl transferase,CPT)基因在绵羊和山羊不同组织中的表达差异。研究结果表明,CPT1A mRNA在绵羊肝脏、脾脏中表达明显高于CPT1B、CPT2,CPT1B mRNA在绵羊腹外斜肌中的表达明显高于CPT1A、CPT2。CPT1A mRNA在山羊脾脏中表达明显高于CPT1B、CPT2 mRNA在山羊脾脏中的表达,CPT1B mRNA在山羊后腿股二头肌、腹外斜肌中的表达明显高于CPT1A、CPT2 mRNA在山羊后腿股二头肌中的表达。CPT1A mRNA在绵羊肝脏中的表达显著高于山羊中CPT1A mRNA的表达(P＜0.05)。CPT1A、CPT1B、CPT2基因在绵羊心脏、脾脏、腰大肌中的表达显著高于在山羊中的表达(P＜0.05),CPT1A、CPT1B、CPT2基因在山羊后腿股二头肌中的表达显著高于在绵羊中的表达(P＜0.05)。CPT1A、CPT1B、CPT2基因在绵羊、山羊各组织中的表达存在差异,可能与各基因表达模式、肌肉组织纤维类型、脂肪沉积含量不同等因素有关。     

Bovine longissimus muscle glycogen concentration in response to isometric contraction and exogenous epinephrine

Isometric contraction was elicited in cattle by electrical stimulation (electrical immobilization) and was used as a means of investigating the interaction between muscle contraction and epinephrine-induced muscle glycogen degradation. At 0.5 and 24 hours after a 15-minute period of continuous muscle contraction, glycogen content of longissimus muscle specimens collected via needle biopsy was not different from precontraction concentrations. Epinephrine (13.2 mg/kg of body weight) given subcutaneously resulted in a 30% to 35% reduction of muscle glycogen. Reduction of muscle glycogen was slightly greater when epinephrine was used in conjunction with isometric contraction, compared with epinephrine treatment alone. Muscle glycogen increased, and free glucose, lactate, and glucose-6-phosphate decreased, with increases in body weight. In younger, lighter cattle (370 kg), epinephrine decreased muscle glycogen and lactate concentrations and generally decreased muscle glucose concentrations. Muscle-free glucose and lactate concentrations were increased in older, heavier cattle (446 kg) by contraction and epinephrine injection when the animals were immobilized for 30 minutes, with intermittent periods of muscle relaxation. In these cattle, muscle glycogen concentration slightly decreased with isometric contraction. Data indicate that reports of increased glycogenolysis observed in cattle subjected to stress by mixing strange animals or exercise is due to dynamic muscle contraction and not due to isometric muscle contraction.     

Fetal development in the pig in relation to genetic merit for piglet survival

The objective of this study was to investigate if litters with different genetic merit for piglet survival differ in late fetal development. In total, 507 fetuses from 46 litters were delivered by Caesarean section at, on average, d 111 of gestation. All litters had known estimated breeding values for piglet survival (EBVps). The obtained range of EBVps of the litters was continuous, and the difference between litters with the lowest and highest EBVps was 16.4%. Analysis of relationships between fetal characteristics and EBVps was performed with litter averages, using linear regression analysis with inclusion of EBVps as a covariate. An increase in EBVps of the litter was associated with decreases in average placental weight (P = 0.01) and within-litter variation in placental weight (P = 0.02), and an increase in average placental efficiency (P = 0.08). Average fetal length decreased with increasing EBVps (P = 0.04), but weights of liver (P = 0.02), adrenals (P = 0.0001), and small intestine (P = 0.01) showed relative increases with increasing EBVps. Average serum cortisol concentrations increased with increasing EBVps (P = 0.0001), but the other blood characteristics (hematocrit, glucose, fructose, albumin, estradiol-17beta) were not related to EBVps. Glycogen concentrations in liver (P = 0.07) and longissimus dorsi muscle (P = 0.04) and total liver glycogen content (P = 0.05) increased with increasing EBVps, whereas heart glycogen concentration decreased with increasing EBVps (P = 0.005). The percentage of carcass fat increased with increasing EBVps (P = 0.05). Relationships of relative liver weight, relative small intestinal weight, and liver and muscle glycogen levels with EBVps were absent after adjustment for differences in cortisol levels between litters. The observed differences in fetal development in relation to EBVps suggest a higher degree of physiological maturity in litters with high EBVps. Differences in fetal cortisol most likely accounted for most of these maturational differences. The results imply that selection for improved piglet survival will lead to slightly smaller piglets that nevertheless have an improved ability to cope with hazards during birth or within the first days of life.     

Pre- and postweaning performance of pigs injected with dexamethasone at birth

A trial was conducted to determine pre- and postweaning performance of pigs injected with dexamethasone either 1 or 24 h after birth. In Exp. 1, 225 pigs (Triumph4 x PIC Camborough 22) were assigned according to birth weight and sex to three treatments. Treatments included either saline (Control), Dex1 (2 mg/kg BW i.m. injection of dexamethasone within 1 h of birth), or Dex24 (2 mg/kg BW i.m. injection of dexamethasone within 24 h after birth). Birth weights (1.56 +/- 0.06 kg) did not differ among treatments (P > 0.10) or between sexes (P > 0.10). There was a treatment x sex interaction on BW at weaning (15 d; P < 0.05) with Dex1 and Dex24 males 10% heavier than Control males (4.77 and 4.78 vs. 4.34 kg, respectively), and no significant differences in BW among the females (P > 0.05). In Exp. 2, 180 pigs from Exp. 1 were transported to a segregated early weaning nursery facility where each sex was assigned to 10 pens per treatment (60 pens total). Pigs were fed fortified corn-soybean meal diets in a three-phase feeding program. At the end of Exp. 2 (49-d period), there was a treatment x sex interaction (P < 0.01) for BW with Dex1 and Dex24 barrows being on average 8% heavier than the Control barrows (30.1 and 29.8 vs. 27.7 kg, respectively), and no significant difference in BW (P > 0.10) among the gilts. No treatment differences in feed efficiency (gain:feed) were observed during the nursery period (P > 0.10). In Exp. 3, pigs from the nursery were moved to a finishing facility where each sex was assigned to 4 pens per treatment (24 pens total). All pigs were fed fortified corn-soybean meal diets in a four-phase feeding program with sexes fed separately. Real-time ultrasound was used to measure 10th rib backfat depth and longissimus muscle area. At the end of Exp. 3 (83-d period), there was a treatment x sex interaction (P < 0.05) for final BW with Dex1 and Dex24 barrows being on average 5.45 kg heavier than Control barrows (119.6 and 120.7 vs. 114.4 kg, respectively), and no difference (P > 0.05) in BW among the gilts. No treatment differences (P > 0.10) were observed for backfat depth, longissimus muscle area or gain:feed. These studies demonstrate that dexamethasone (2 mg/kg BW) given within 24 h of birth significantly improves both pre- and postweaning performance of barrows with no beneficial effects on gilts.     

努比亚山羊LMCD1基因生物信息学分析、真核表达载体的构建及表达

【目的】 扩增努比亚山羊LIM结构域基因1（LIM domain gene 1,LMCD1）并进行生物信息学分析,构建真核表达载体并检测LMCD1基因的表达情况,为研究努比亚山羊LMCD1基因功能及探究LMCD1基因在山羊骨骼肌肉发育中的作用提供依据。【方法】 从努比亚山羊背最长肌组织中提取总RNA,应用RT-PCR方法扩增LMCD1基因CDS区序列,并进行生物信息学分析;将LMCD1基因以同源重组的方式连接pEGFP-N1载体,经酶切、测序鉴定后重组阳性质粒命名为pEGFP-N1-LMCD1;将pEGFP-N1-LMCD1重组质粒转染至山羊骨骼肌卫星细胞,通过实时荧光定量PCR检测努比亚山羊LMCD1基因的表达情况。【结果】 努比亚山羊LMCD1基因CDS区序列全长1 092 bp,编码363个氨基酸。LMCD1蛋白分子式为C₁₇₇₅H₂₈₁₈N₅₀₈O₅₃₃S₂₉,分子质量为40.73 ku。努比亚山羊LMCD1基因CDS区序列与山羊相似性最高（99.8%）,与斑马鱼相似性最低（55.4%）,与其他物种的相似性在87.0%~98.8%之间。LMCD1蛋白无信号肽,不存在跨膜结构域,为亲水性蛋白。通过构建努比亚山羊pEGFP-N1-LMCD1真核表达载体并转染至骨骼肌卫星细胞,过表达LMCD1基因,产生绿色荧光信号。【结论】 试验成功扩增LMCD1基因CDS区序列,构建了pEGFP-N1-LMCD1真核表达载体,并分析了生物学功能,为后续开展LMCD1基因在山羊骨骼肌肉发育中的机制研究提供了理论基础。     

Use of biochemical and biophysical indicators in muscles (m. longissimus dorsi) obtained by harpoon biopsy in predicting the quality of pork

Forty-two pigs (German Landrace and commercial hybrids) were subjected to harpoon biopsy. A possibility of using the biochemical (adenosine triphosphate, creatine phosphate, glucose-6-phosphate, glucose, lactate, glycogen) and biophysical (pH value, R-value, water-binding capacity) parameters of muscle (m. longissimus dorsi) for forecasting the quality of pork was demonstrated. The post-mortem processes were simulated in muscle bioptate (1 hour of incubation at 39 degrees C). The highest correlations with meat quality in slaughtered animals (pH) were recorded in adenosine triphosphate, creatine phosphate, R-value, pH value, lactate and glycogen. No significant differences were found between the left and right side of the muscle (m. longissimus dorsi) in the studied parameters.