原鸡与家鸡杂交F_1代肉质特性分析

以原鸡滇南亚种(父本)与原鸡(母本)、茶花鸡(母本)、绿耳乌骨鸡(母本)、楚雄麻鸡(母本)不同组合F1代为研究素材,分析比较了其常规肉质性状和基本营养成分。结果表明:宰后45 min,原鸡杂交F1代胸、腿肌pH值显著低于纯种原鸡(P<0.05),宰后24 h pH值与宰后45 min相比呈下降趋势,纯种原鸡下降最为明显;胸、腿肌系水力、滴水损失率、蒸煮损失率、肌纤维直径(密度)等指标在不同组合间多数存在显著差异(P<0.05)。就营养成分而言,胸、腿肌水分含量及胸肌粗蛋白含量在各组合间差异均不显著(P>0.05),原鸡(父本)与茶花鸡(母本)杂交F1代、纯种原鸡腿肌粗蛋白含量显著高于其余两组(P<0.05);胸肌及腿肌的粗脂肪、粗灰分含量在不同组合间存在差异,且多数达到显著水平(P<0.05)。总体而言,原鸡(父本)与茶花鸡(母本)肉质特性杂种优势较大,原鸡(父本)与楚雄麻鸡(母本)杂种优势较小。     

Cholecalciferol-induced bait shyness in possums (Trichosurus vulpecula)

Cholecalciferol (vitamin D₃) is used in a variety of bait formulations to control populations of the brushtail possum (Trichosurus vulpecula), an introduced pest that seriously damages and threatens primary production and native biota in New Zealand. In cage trials, possums readily ate sublethal baits containing either an estimated LD₁₅ or LD₄₀ dose of cholecalciferol, leading to a depression of appetite that lasted for 7-15 days. When lethal quantities of baits were presented 21-30 days after the initial LD₁₅ or LD₄₀ baits, 40 and 88% of possums survived, respectively, compared with a 21% survival rate among naive possums, and bait consumption was also reduced among survivors of the initial baits. Subsequent switching of the bait base to a gel was partially successful in overcoming bait shyness, killing 40% of one group (formed by pooling the original groups), while switching both the bait type (to gel) and the toxicant (to 1080) resulted in a 63% mortality rate in a second group. By comparison, 95 and 100% of naive groups were killed by cholecalciferol and 1080 gel respectively. Practical measures are identified for both avoiding and overcoming bait shyness based on the use of alternative bait types and toxicants.     

虹鳟肌肉纤维组织学特性研究

[目的]为虹鳟肉质评定提供参考。[方法]用显微镜对组织切片进行观察,研究不同体重的虹鳟肌肉纤维组织学特性(背最长肌)。[结果]体重60～90 g虹鳟的肌肉纤维密度达到峰值,为(698.47±9.75)n/mm2;体重90～120 g虹鳟的肌肉纤维密度为(644.31±14.23)n/mm2;体重120～150 g虹鳟的肌肉纤维密度为(610.86±15.45)n/mm2;体重150～180 g虹鳟的肌肉纤维密度为(578.51±16.38)n/mm2;体重180～210 g虹鳟的肌肉纤维密度为(521.22±13.27)n/mm2。体重60～90 g虹鳟的肌纤维直径为(41.13±1.93)μm;体重90～120 g虹鳟的肌纤维直径为(43.67±1.49)μm,体重120～150 g虹鳟的肌纤维直径为(44.92±2.33)μm,体重150～180 g虹鳟的肌纤维直径为(46.38±0.94)μm,体重180～210 g虹鳟的肌纤维直径为(48.22±1.38)μm。[结论]随着体重的增加,虹鳟的肌纤维密度减小、肌纤维直径增加,但其变化幅度由营养状况、年龄和体重决定。     

人工养殖鲟鱼生长与肌肉品质的研究进展

鲟鱼肉和卵极具营养价值,鲟鱼养殖规模稳定扩大,中国已经成为世界上最大的鲟鱼养殖国家。尽管国内外在鲟鱼保护生物学和应用技术方面取得了一系列科研成果,但对养殖鲟鱼的生长和肌肉品质的发育规律所知甚少。本文综述了国内外养殖鲟鱼异速生长模式和肌肉品质分析的研究现状,发现现有鲟鱼生长于肌肉品质的研究主要集中于幼鱼或某一个生长期,缺少系统性和完整性。因此,建议针对主要养殖鲟鱼品种,从幼鱼到成鱼系统开展养殖鲟鱼生长与肌肉品质变化规律的研究,揭示鲟鱼肌肉品质的生长发育规律。     

A selectively suppressing amino acid transporter: Sodium-coupled neutral amino acid transporter 2 inhibits cell growth and mammalian target of rapamycin complex 1 pathway in skeletal muscle cells

Sodium-coupled neutral amino acid transporter 2 (SNAT2), also known as solute carrier family 38 member 2 (SLC38A2), is expressed in the skeletal muscle. Our research previously indicated that SNAT2 mRNA expression level in the skeletal muscle was modulated by genotype and dietary protein. The aim of this study was to investigate the key role of the amino acid transporter SNAT2 in muscle cell growth, differentiation, and related signaling pathways via SNAT2 suppression using the inhibitor α-methylaminoisobutyric acid (MeAIB). The results showed that SNAT2 suppression down-regulated both the mRNA and protein expression levels of SNAT2 in C2C12 cells, inhibited cell viability and differentiation of the cell, and regulated the cell distribution in G0/G1 and S phases (P < 0.05). Meanwhile, most of the intercellular amino acid content of the cells after MeAIB co-culturing was significantly lower (P < 0.05). Furthermore, the mRNA expression levels of system L amino acid transporter 1 (LAT1), silent information regulator 1, and peroxisome proliferator-activated receptor-gamma co-activator 1 alpha, as well as the protein expression levels of amino acid transporters LAT1 and vacuolar protein sorting 34, were all down-regulated. The phosphorylated protein expression levels of mammalian target of rapamycin (mTOR), regulatory-associated protein of mTOR, 4E binding protein 1, and ribosomal protein S6 kinase 1 after MeAIB treatment were also significantly down-regulated (P < 0.05), which could contribute to the importance of SNAT2 in amino acid transportation and skeletal muscle cell sensing. In conclusion, SNAT2 suppression inhibited C2C12 cell growth and differentiation, as well as the availability of free amino acids. Although the mTOR complex 1 signaling pathway was found to be involved, its response to different nutrients requires further study.     

家禽肌肉组织中硝基咪唑类药物残留高效液相色谱检测法研究

 建立了检测家禽肌肉组织中甲硝唑、洛硝哒唑、二甲硝咪唑残留的高效液相色谱法。样品经乙酸乙酯振荡提取 ,浓缩 ,盐酸溶解残渣 ,己烷萃取除去脂肪。氢氧化钠调节溶液到pH 4 .8～ 5 .2 ,过C18小柱 ,甲醇洗脱 ,SpherisorbC18柱分离 ,32 0nm处检测。流动相为醋酸缓冲液 乙腈 (85∶15 ,v/v)。甲硝唑、洛硝哒唑和二甲硝咪唑检测限分别为 0 .5、1.0和 1.0ng·g-1。肉鸡肌肉组织中添加 6 .0ng·g-1水平回收率分别为 :甲硝唑 89.8% ,洛硝哒唑81.7% ,二甲硝咪唑 86 .6 %。此方法具有定性合理 ,检测限低 ,分析快速 ,准确等特点。     

兔疥螨体壁和肌肉超微结构的研究

透射电镜观察表明：兔疥螨（Ｓａｒｃｏｐｔｅｓｓｃａｂｉｅｉ）雌性成虫的体壁由表皮层和真皮组成．表皮层由上表皮、外表皮和内表皮组成．其中上表皮又可分为盖质层和表皮质层．真皮层则由一单层的表皮细胞层所构成．起源于表皮细胞的微管穿过内、外表皮，终止于近盖质层的表皮质层内，为单线型微管．本文还对皮纹、皮棘、杆状毛和基腹板等体壁附属构造进行了观察．骨胳肌细胞由肌质膜、肌质和核所组成．肌质膜为双层单位膜所组成．肌质内含肌原纤维、肌质网、线粒体、β－型糖原以及少许脂滴．肌原纤维显示色淡的Ｉ带和色深的Ａ带相间排列，Ｉ带中心为Ｚ线．Ａ带中每条粗肌丝周围配有９～１１条细肌丝．核单个，内含多量常染色质，核仁一个，电子密度深，位于一端．     

野生及人工养殖暗纹东方鲀肌肉营养成分的比较分析(英文)

[Objective] The aim of this study was to evaluate the nutritive value of Takifugu obscurus and provide the scientific basis for artificially feed research.[Method] The nutrient components and nutritive qualities in the muscle of wild and artificially reared Takifugu obscurus were comparatively analyzed.[Result] The contents of crude protein,crude fat,crude ash,total amino acids,essential amino acids and half essential amino acid in the muscle of wild Takifugu obscurus were all higher than those of the artificially reared.The content of four delicious amino acids in the muscle of wild and artificially reared Takifugu obscurus was 17.59% and 14.44%(percentage of dry weight),respectively.The essential amino acid index(EAAI)was 52 and 40 separately,and the constitutional rate of the essential amino acids met the FAO/WHO standard.Valine was the first limiting amino acid of Takifugu obscurus.[Conclusion] The muscle of wild and artificially reared Takifugu obscurus were all high quality food full of animal protein,while the protein nutritive value of wild Takifugu obscurus was higher than that of the artificially reared.     

朗德鹅肌肉生成抑制因子基因（MSTN）的克隆及其表达量与日粮能量、血清IGF-I和GH的关系

 【目的】采用反转录－聚合酶链反应（RT-PCR）技术,克隆朗德鹅肌肉生成抑制因子基因（MSTN）,研究MSTN基因表达和日粮能量及其部分血清激素含量的相互关系,了解MSTN的功能,为水禽分子营养和分子育种提供基础资料。【方法】从朗德鹅（Anser anser）的腿肌中抽提总RNA,用两步法RT-PCR扩增出MSTN基因的cDNA编码序列,以pGEM-T Vector为载体,将该片段克隆到大肠杆菌（Escherichia coli）中。通过筛选阳性克隆,双酶切鉴定后测序;以MSTN基因的克隆为基础,以β-actin为内标,构建优化的半定量RT-PCR方法,研究高中低（A:13.38MJ•kg-1、B:12.13MJ•kg-1、C:10.87MJ•kg-1）3种不同能量对朗德鹅21日龄和70日龄2个时期,肌肉组织MSTN基因表达的差异;同时用放免法测定21、70日龄的血清GH和IGF-I浓度。【结果】克隆朗德鹅MSTN基因cDNA的部分序列,其片段大小为1 128bp,编码375个氨基酸组成的多肽,与已发表的鸡、鸭、鹅的MSTN 核苷酸相似性分别为94%、94%、99%;氨基酸的相似性分别为98%、97%、98%;21日龄时,朗德鹅公鹅、母鹅MSTN表达量差异不显著;70日龄时朗德鹅公鹅MSTN的表达量情况为能量A＞C＞B,朗德鹅母鹅MSTN的表达量情况为C＞B＞A;对于朗德鹅21～70日龄阶段的生长,MSTN基因的表达量和血清IGF-I的变化基本一致;与血清GH含量之间并不存在很大关联,GH和能量的高低呈正相关。【结论】日粮能量对21日龄后朗德鹅MSTN基因的表达有影响,且MSTN基因表达量和血清IGF-I具有相关性,和血清GH无较大相关性。     

A method for inducing muscle relaxation in the abalone, Haliotis iris

Four chemical and two non-chemical methods for induction of relaxation in the abalone, Haliotis iris, were tested for prospective use in pearl seeding. Requirements were for rapid onset of relaxation, full extension and softening of the foot and epipodium muscle for at least 10 min, and recovery with minimal stress and no mortality. Nembutal at 1 ml/l was most successful, producing relaxed and soft muscle with good accessibility to operation sites, and no mortality. Benzocaine and MS-222 made animals release from container walls within 30–60 min, but the animal's muscle was hard and contracted. Propylene phenoxytol caused muscle contraction and mortality at 2.5 ml/l. The effects of the chemical relaxants were similar in warm (21–22.5°C) and cool (15–16°C) water. Elevation of the water temperature from 18°C to 23°C (without chemicals) caused some softening of the muscle, but was much less effective than Nembutal. Air exposure for up to 4 h was ineffective. This work provides a simple method to relax live abalone for pearl nucleation or other manipulations.