不同冻存法对肌肉冰冻切片后HE染色和肌球蛋白ATP酶染色效果的影响

使用分步法和一步法冻存巴马香猪背最长肌,冰冻切片后比较苏木精-伊红染色法(HE染色)和肌球蛋白三磷酸腺苷酶染色法(ATP酶染色)效果。结果表明:分步法冻存的肌肉样品冰晶少,细胞形态完整,HE染色效果好,核质明显;ATP酶染色效果好,可较好地区分Ⅰ型Ⅱ型肌纤维。一步法冻存的肌肉样品冰晶多,细胞形态不完整,HE染色效果差,核质模糊;ATP酶染色效果差,基本染不上色,无法对肌纤维类型进行区分。分步冻存法的建立为通量式制备猪肉的恒冻切片奠定了基础,也为进一步开展相关性状的生理学、遗传学及种猪选育提供了很好的表型测定方法。     

Postnatal changes in electromyographic signals during piglet growth, and in relation to muscle fibre types

This study uses non-invasive evoked surface electromyography (SEMG) to investigate postnatal muscle development in pigs, and to assess any correlation between recorded signal parameters and muscle fibre types in two different skeletal muscles. Four litters (n = 43) of Large White × Landrace pigs were used. Evoked SEMG measurements were taken on days 2, 5, 14, 26, 60 and 151 post partum from m. Longissimus dorsi (LD) and on days 14, 26, 60 and 151 post partum from m. Biceps femoris (BF). A third of each litter was slaughtered at days 27, 61 and 153 post partum. Biopsy samples for LD and BF were taken to categorize muscle fibre types. For LD there was a significant increase in compound muscle action potential (CMAP) parameters from day 2 to day 5 post partum, whilst for BF significant increases occurred from days 14 to 26 post partum. Fibre type development in both muscles showed a significant decrease in type IIA fibre number (P < 0.001) and an increase in type IIB fibre number (P < 0.001). Analysis of CMAP parameters in relation to fibre type percentages showed significant positive correlations between percentage of type I fibres in BF and CMAP Area (r = 0.71; P = 0.05), SlopeL (r = 0.79; P = 0.02) and Corr Peak (r = 0.78; P = 0.02) and a negative correlation with SlopeT (r = 0.89; P = 0.003) at day 151. A greater CMAP Area and Corr Peak as well as steeper leading and trailing slopes were on the other hand correlated to fewer type IIB fibres.

It is concluded that 1) changes in the evoked CMAP are muscle-specific during early postnatal development in the pig, and 2) in spite of a small sample size, the correlations between CMAP signal parameters and fibre type percentages warrant further investigation.     

Dietary dimethylglycine sodium salt supplementation improves growth performance,redox status,and skeletal muscle function of intrauterine growth-restricted weaned piglets

Few studies have focused on the role of dimethylglycine sodium (DMG-Na) salt in protecting the redox status of skeletal muscle, although it is reported to be beneficial in animal husbandry. This study investigated the beneficial effects of DMG-Na salt on the growth performance, longissimus dorsi muscle (LM) redox status, and mitochondrial function in weaning piglets that were intrauterine growth restricted (IUGR). Ten normal birth weight (NBW) newborn piglets (1.53 ± 0.04 kg) and 20 IUGR newborn piglets (0.76 ± 0.06 kg) from 10 sows were obtained. All piglets were weaned at 21 d of age and allocated to the three groups with 10 replicates per group: NBW weaned piglets fed a common basal diet (N); IUGR weaned piglets fed a common basal diet (I); IUGR weaned piglets fed a common basal diet supplemented with 0.1% DMG-Na (ID). They were slaughtered at 49 d of age to collect the serum and LM samples. Compared with the N group, the growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression deteriorated in group I (P < 0.05). The ID group showed improved growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression compared with those in the I group (P < 0.05). The above results indicated that the DMG-Na salt treatment could improve the LM redox status and mitochondrial function in IUGR weaned piglets via the nuclear factor erythroid 2-related factor 2/sirtuin 1/peroxisome proliferator-activated receptorγcoactivator-1α network, thus improving their growth performance.     

When a general morphology allows many habitat uses

During the last decades the study of functional morphology received more attention incorporating more detailed data corresponding to the internal anatomy that together contribute for a better understanding of the functional basis in locomotion. Here we focus on 2 lizard families, Tropiduridae and Liolaemidae, and use information related to muscle‐tendinous and external morphology traits of hind legs. We investigate whether the value of the traits analyzed tend to exhibit a reduced phenotypic variation produced by stabilizing selection, and whether species showing specialization in their habitat use will also exhibit special morphological features related to it. As a result, we identified that evolution of hind limb traits is mainly explained by the Ornstein–Uhlenbeck model, suggesting stabilizing selection. Liolaemids and tropidurids show clear ecomorphological trends in the variables considered, with sand lizards presenting the most specialized morphological traits. Some ecomorphological trends differ between the 2 lineages, and traits of internal morphology tend to be more flexible than those of external morphology, restricting the ability to identify ecomorphs shared between these 2 lineages. Conservative traits of external morphology likely explain such restriction, as ecomorphs have been historically defined in other lizard clades based on variation of external morphology.     

t10,c12-CLA对猪皮下脂肪和背最长肌组织脂类代谢的影响

试验首先建立了30日龄猪皮下脂肪和背最长肌组织块体外培养体系,共设2个处理,处理1为阴性对照（添加0.1mmol/L牛血清白蛋白,BSA）,处理2添加100μmol/L的t10,c12-CLA,每个处理设6个平行,接种时即加入BSA与t10,c12-CLA进行处理至第10天,试验结束后收集细胞保存备用。采用荧光定量PCR技术及试剂盒检测研究t10,c12-CLA对猪皮下和背最长肌脂肪代谢关键酶（FAS、ME、LPL、HSL）和激素（INSR、GHR）及甘油三酯（TG）合成的影响。结果表明：①100μmol/Lt10,c12-CLA显著降低了猪皮下脂肪TG含量并提高了猪背最长肌的TG含量（P〈0.05）;②100μmol/Lt10,c12-CLA显著抑制了猪皮下脂肪FAS、INSR与背最长肌HSL和LPL的基因表达,促进了猪皮下脂肪HSL和背最长肌INSR的基因表达（P〈0.05）;③该研究结果从脂肪代谢关键酶类与调控激素方面揭示了t10,c12-CLA对猪皮下和背最长肌组织脂肪代谢与沉积的差异性调控机制,进一步证实了t10,c12-CLA抑制猪皮下脂肪沉积同时提高肌内脂肪含量。     

基于数学形态学的牛肉图像中背长肌分割和大理石纹提取技

牛肉图像中背长肌区域的分割和大理石纹提取是利用计算机视觉评定牛肉胴体等级的重要步骤.研究了利用数学形态学的方法来分割牛肉眼肌切面图像中背长肌区域并将大理石纹提取出来的技术.眼肌切面图像经过去除背景并进行肌肉和脂肪像素识别等预处理后,再用形态学腐蚀与膨胀相结合获得背长肌区域图像,通过图像逻辑运算提取大理石纹.结果表明,这种方法能有效地把背长肌区域与其周围肌肉组织分离开来并提取大理石纹.     

早期断奶对藏西北绒山羊背最长肌氨基酸和脂肪酸含量的影响

[目的] 研究早期断奶对藏西北绒山羊背最长肌中氨基酸和脂肪酸含量的影响。[方法] 将18只健康羔羊按照体重相近原则随机分为试验组和对照组,试验组在28日龄（D28）实施早期断奶,对照组在60日龄（D60）自然断奶,羔羊断奶后饲喂相同的代乳料至75日龄;从两组随机选取5只羔羊进行屠宰采样,对其背最长肌中氨基酸和脂肪酸指标进行测定分析。[结果] 在藏西北绒山羊背最长肌中检测出17种氨基酸,包括赖氨酸、亮氨酸等7种必需氨基酸,天冬氨酸、精氨酸等10种非必需氨基酸。两组断奶羔羊肉中总氨基酸含量、必需氨基酸含量、非必需氨基酸含量均无显著差异（P>0.05）,28日龄断奶组羔羊肉中EAA/TAA、EAA/NEAA比值显著（P<0.05）高于60日龄断奶羔羊。共检测出29种饱和脂肪酸、不饱和脂肪酸,以棕榈酸和油酸含量最高,早期断奶对羔羊肉中饱和脂肪酸含量、单不饱和脂肪酸含量以及多不饱和脂肪酸含量影响不显著（P>0.05）。[结论] 藏西北绒山羊羔羊肉中所含氨基酸和脂肪酸种类多、含量丰富,实施早期断奶、及早补充颗粒料对肉中脂肪酸和氨基酸含量无影响,且可提高EAA/TAA、EAA/NEAA比值,使其更符合FAO/WHO氨基酸评分模式;该试验可为藏西北绒山羊羔羊实施早期断奶、提高母羊的繁殖率提供参考。     

维生素E缺乏对鲤骨骼肌损伤的影响

本文旨在探讨VE缺乏对鲤骨骼肌损伤的形态学影响。在半纯合日粮中分别添加0、25、50和100 mg/kg的VE,投喂体重约60 g的鲤鱼20周。结果表明:鲤鱼摄入VE缺乏的饲料后,出现“瘦背症”、脊柱弯曲及以突眼、竖鳞和腹水为特征的渗出性素质样病变。病理剖解见体壁肌肉萎缩,特别是背部两侧肌肉萎缩变薄,其厚度仅为对照组的1/4~1/2,似刀刃状;体侧红肌纤维褪色变白,呈白肌肉外观。组织学变化主要表现为肌营养性不良,骨骼肌变性、坏死,淋巴细胞和单核细胞浸润,大量结缔组织增生,残存的肌纤维萎缩变细。超微结构上表现为骨骼肌细胞核膜间隙增宽,呈锯齿状,并发生局部或广泛性的断裂,核变形,电子密度降低;肌浆内糖原颗粒明显减少,线粒体肿胀,嵴断裂,甚至溶解呈空囊泡状,肌原纤维的横纹模糊不清或完全消失。结论:日粮中0、25和50 mg/kgVE水平会导致鲤出现VE缺乏症,其骨骼肌主要表现为变性、坏死、肌萎缩和炎症细胞浸润的肌营养性不良。     

运动诱发肉鸡胸深肌病的病理学研究

强迫肉鸡进行拍翅运动诱发胸深肌病,１９只试验鸡在６ｄ中拍翅７次,有８／１９只发生典型胸深肌病,其中单侧或双侧胸深肌病各占４例。胸深肌病的病变程度不等,有些病例只有局部病变。严重急性病例整块肌肉出血、肿胀,呈深绿色,在胸深肌和胸浅肌之间有大量纤维素性血色渗出物并在肌块表面形成伪膜。胸浅肌和体内其它肌肉正常,只在严重病例的胸浅肌内侧面充血或出血。胸深肌病的病理组织学变化是出血性坏死性肌炎,肌肉出现变性、坏死、炎症和再生。并分析了胸深肌病的发生原因和发生机理,以及和屠猪运输应激引起的腿肌坏死相似性。