秦川肉牛新品系的培育

产于陕西八百里秦川的秦川牛,千百年来一直是关中农业生产的主要动力和粪肥来源,建国后,通过广大科技工作者的通力合作,协同攻关,运用国际育种先进技术,选出优秀公牛,授配主产区大批秦川母牛,配合其他措施,从而加速了秦川牛的选育,使之很快由役用型转变为肉用型,形成了秦川肉牛新品系。经屠宰测定,其肉用,役用性能不仅大大高于５０年代调查时测定的指标,而且其中一些肉用性能指标与国际著名的肉牛品种相比也毫不逊色,     

乌梅不同药用部位对豚鼠离体胆囊平滑肌的作用

目的:观察乌梅、乌梅肉、乌梅核对豚鼠离体胆囊平滑肌的作用,探讨其作用机制。方法:采用离体胆囊平滑肌实验法。结果:乌梅、乌梅肉、乌梅核0.5～20.0g·L-1抑制豚鼠离体胆囊平滑肌活动,收缩频率减慢,幅度降低,张力下降;8.0g·L-1对氯化钾及氯化钡所致胆囊收缩有松弛作用;0.5～8.0g·L-1对乙酰胆碱和组胺致胆囊收缩有松弛作用。结论:乌梅、乌梅肉、乌梅核对豚鼠离体胆囊平滑肌具有抑制作用,该作用可能与其拮抗钙离子有关。     

饲料中维生素K3含量对大口黑鲈消化能力、血清代谢指标、肌肉氨基酸和脂肪酸组成的影响

为研究饲料中维生素K₃含量对大口黑鲈消化能力、血清代谢指标、肌肉氨基酸和脂肪酸组成的影响,在基础饲料中分别添加不同水平的维生素K₃,配制成维生素K₃含量分别为0.78(K0组)、5.80(K5组)、10.82(K10组)、15.84(K15组)和20.85 mg/kg(K20组)的5种试验饲料,对初均重为(12.96±0.07)g健康大口黑鲈幼鱼进行为期8周的饲养试验。结果表明:添加维生素K₃的各组胃和肠道的蛋白酶、淀粉酶和脂肪酶活性均显著低于K0组(P<0.05)。K10组、K15组和K20组的表观消化率和蛋白质表观消化率显著低于K0组(P<0.05)。K20组的血清尿素氮含量显著高于其他4组(P<0.05),血清总蛋白、白蛋白、总胆固醇和甘油三酯含量在各组之间无显著差异(P>0.05)。肌肉必需氨基酸、非必需氨基酸和总氨基酸含量以及必需氨基酸指数在各组之间无显著差异(P>0.05),但是随着饲料中维生素K₃含量的增加,必需氨基酸和总氨基酸含量呈增加的趋势。K15组的肌肉单不饱和脂肪酸含量显著高于其他4组(P<0.05),其中C16∶1n7和C18∶1n5含量均较其他组显著升高(P<0.05)。肌肉饱和脂肪酸和多不饱和脂肪酸含量在各组之间无显著差异(P>0.05)。综上可知,饲料中添加维生素K₃可以改善大口黑鲈肌肉氨基酸组成,但当饲料中维生素K₃含量≥5.80 mg/kg时会使大口黑鲈的消化能力下降,并且高剂量的维生素K₃会改变大口黑鲈的蛋白质和脂质代谢。     

一水肌酸对杜浙猪肉质性状、肌肉磷酸原代谢、纤维类型特征及蛋白质溶解度的影响

本文旨在研究饲粮添加一水肌酸(CMH)对杜浙猪肉质性状、肌肉磷酸原代谢、纤维类型特征及蛋白质溶解性的影响。试验选取体重70 kg左右杜浙猪30头,随机分为2组,每组5个重复,每个重复3头猪。对照组饲喂基础饲粮,试验组饲喂基础饲粮+0.5%CMH,试验期30 d。结果显示:与对照组相比,饲粮添加CMH对杜浙猪生长性能无显著影响(P0.05),使背最长肌宰后24 h p H和剪切力显著增加(P0.05),滴水损失和压榨损失显著降低(P0.05),背最长肌的肌酸(Cr)总量、磷酸肌酸(PCr)储备量、肌酸激酶(CK)活性、白蛋白及肌原纤维蛋白溶解度显著增加(P0.05),背最长肌肌球蛋白重链(My HC)Ⅱa mRNA比例显著降低(P0.05)。结果提示,饲粮添加CMH对杜浙猪肉质性状具有调控作用,对肌肉磷酸原代谢能力、蛋白质溶解度及肉品系水力产生显著影响。     

Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter

Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids.     

Positional strategy of trunk muscles among aquatic,semi-aquatic and terrestrial species in Urodela

Clarification of the trunk structure in Urodela is important in understanding the locomotive evolution of basal tetrapods. The components of the muscular trunk wall among Urodela using different modes of locomotion were compared. Since the whole trunk may be used for swimming and the effect of limbs may be small in the more aquatic species, they showed smaller differences in the trunk muscles among anterior, middle and posterior sections of the trunk. By contrast, in the more terrestrial species, the dorsal and abdominal muscles are larger in the middle section than those in the anterior and posterior sections. High compressive stresses occur in the supporting limbs and their insertion at the trunk on the ventral side, and spread from the forelimbs along the back to the supporting hindlimbs on the dorsal side. Tensile stresses occur in the middle ventral part. The components of the trunk muscles among the three sections may reflect differences in stresses occurring in the trunk of the more terrestrial species. The findings also suggest that in the middle section, larger dorsal muscles for stiffening the back to maintain posture and larger abdominal muscles are responsible for balancing the body weight while it is supported by the limbs in the more terrestrial species.     

The Expression of Long Noncoding RNA (H19) in Mouse Skeletal Muscle Development

This experiment was intend to study the changes of long non-coding RNA (H19) expression levels in skeletal muscle development and regeneration,and lay the foundation of its mechanism reach in skeletal muscle development.C2C12 cell line and ICR mice were used as experimental material,bioinformatics assay was used to exploit its non-coding character and low conservatism in different species,and the expressions of H19 in C2C12 cell differentiation,skeletal muscle development and the phase of muscle regeneration were detected by quantitative Real-time PCR (qRT-PCR).The results showed that,H19 expression levels in postnatal mouse skeletal muscle decreased with increasing age;during C2C12 cell differentiation,H19 mRNA increased gradually,and then maintained a high level;The expression of H19 was maintained at a high level through days 4 to 6 after injury.In consideration of its express character in C2C12 cell differentiation and skeletal muscle damage repair model,H19 may play an important role in promoting myogenesis and skeletal muscle regeneration.     

Analysis of Regular Nutritional Components and Amino Acid Contents of Mongolia Bullock Muscle Grazed in Kubuqi Desert

In order to evaluate the Mongolia muscle characteristics and nutritional value, six Mongolia bullocks aged 4 years grazed in Kubuqi desert were chosen to analyze the regular nutritional components and amino acid contents of Mongolia muscle.The results showed that the contents of water, crude protein (CP), crude fat (EE), crude ash (ash), calcium and phosphorus of Mongolia muscle (fresh) were 68.21%, 22.60%, 6.49%, 2.69%, 0.58% and 0.55%, respectively.A total amino acid (TAA) content of beef was 24.297 g/100 g, essential amino acid content was 10.265 g/100 g, the proportion of essential amino acid justified and exceeded the FAO/WHO standard.The ratio of essential amino acid and total amino acid contents (EAA/TAA) was 42.25%, the ratio of essential amino acid and the non-essential amino acid (EAA/NEAA) was 73.15%.In functional amino acid, the content of palatable taste amino acid and sweet flavor amino acid in total amino acid was 46.891%.In addition to valine, essential amino acid contents of Mongolia muscle were superior to ideal protein of FAO/WHO standard, the percentage of valine reached 83.972% in ideal protein.These results indicated that Mongolia muscle belonged to the comprehensive nutrition and high quality protein food on the evaluation of the regular nutrient content and the amino acid content of beef.     

Zinc supplementation strategies in feedlot heifers receiving an extended-release implant or an aggressive re-implant program

Two hundred eight Angus-crossbred heifers (291 ± 23 kg) from four sources were used in a randomized complete block design. The objective of the study was to determine the effects of implant strategy and Zn supplementation on performance, carcass characteristics, muscle fiber diameter, and mineral status of heifers. Heifers were assigned to a 2 × 2 factorial study for 168 d, and factors included Zn and implant (IMP). Heifers were supplemented Zn (mg/kg dry matter [DM]; ZnSO₄) at national (30; NRC) or industry (100; IND) recommendations. Implant strategies (Merck Animal Health, Madison, NJ) included extended-release Revalor-XH on day 0 (REV-XH; 20 mg estradiol + 200 mg trenbolone acetate) containing four uncoated pellets and six coated pellets or the uncoated implant Revalor-200 on day 0 and again on day 91 (REV-200; 20 mg estradiol + 200 mg trenbolone acetate). Heifers were blocked by weight within source to pens of five or six heifers per pen (nine pens per treatment). A corn silage-based diet was fed during the growing period (days 0–55) followed by transition to a corn-based finishing diet. Weights were taken consecutively on days −1/0, 55/56, and 167/168. Liver and muscle from the longissimus thoracis were collected from one heifer per pen on days −5, 14, 105, and 164. Data were analyzed via Mixed Procedure of SAS. Average daily gain (ADG) and liver mineral used Period as the repeated effect. Corresponding to periods of high hormone payout from each implant, days 0–28 and 91–120 ADG were greatest for REV-200, whereas REV-XH numerically peaked during days 56–91 (IMP × Period; P = 0.02). Day 91 IND body weight tended to be heavier (P = 0.06) and day 120 body weight was heavier (P = 0.05) than NRC heifers. No effect of Zn or IMP on final body weight was observed (P ≥ 0.21). Muscle fiber cross-sectional diameter on day 164 was greater (P = 0.05) in IND than NRC. Liver Mn concentrations decreased by day 14 regardless of implant, though days 105 and 164 concentrations were lesser for REV-200 than REV-XH (IMP × Period; P = 0.02). No effects of Zn, IMP, or the interaction were observed for carcass-adjusted gain to feed, days 0–168 DM intake, hot carcass weight, or ribeye area (P ≥ 0.11). The nominal differences in performance between implant strategies suggest that extended-release implants may be an effective implant strategy to replace re-implant programs in heifers, whereas the improved performance of heifers fed IND vs. NRC during times of peak hormone payout suggests a role for Zn in periods of rapid growth.     

IL-15过表达对猪骨骼肌细胞成肌分化的影响

【目的】研究肌肉因子IL-15（interleukin 15）对猪骨骼肌成肌细胞增殖与凋亡的影响,为进一步研究IL-15在动物肌肉品质调控和骨骼肌疾病治疗提供依据。【方法】构建IL-15过表达慢病毒载体GV-492-IL-15,体外无菌分离培养猪骨骼肌卫星细胞,诱导分化,并通过免疫荧光染色进行成肌细胞验证。将成肌细胞转染IL-15过表达重组慢病毒载体,试验分别设置空白对照组（Control）、转染阴性对照病毒组（IL-15-）和转染GV-492-IL-15（IL-15+）慢病毒试验组（n=3）。培养72 h后,收集细胞和培养上清液。分别采用实时定量PCR（qRT-PCR）和Western Blot技术分析目的基因和蛋白的表达情况,采用ELISA试剂盒分析培养液中IL-15含量,采用CCK-8试剂盒分析成肌细胞活力,采用流式细胞术分析细胞周期和细胞凋亡,采用Western Blot技术检测与细胞凋亡密切相关的caspase-3蛋白表达水平的变化。【结果】（1）经鉴定后的质粒转染293T细胞,细胞内可观察到明显的绿色荧光,经Western Blot检测,可以观察到20 kD附近处有特征条带;（2）分离培养的猪骨骼肌卫星细胞呈梭形或纺锤形,诱导后可分化为呈管状的成肌细胞。将分化后的成肌细胞,进行α-SMA单克隆抗体免疫荧光染色,视野中90%的细胞呈阳性反应,胞浆染成红色,表明细胞为骨骼肌成肌细胞。（3）转染GV-492-IL-15慢病毒后,与对照细胞组相比,成肌细胞内IL-15 mRNA和蛋白相对表达量均极显著升高（P<0.001）,但培养液中IL-15蛋白水平变化不大（P>0.05）。CCK-8结果显示,过表达IL-15可增强细胞的增殖能力（P<0.05）。与对照组相比,转染GV-492-IL-15慢病毒的细胞早期凋亡率差异不显著（P>0.05）,但细胞晚期凋亡率显著下降（P<0.05）。与对照组相比,转染慢病毒组细胞中caspase-3蛋白有下降的趋势,但差异不显著（P>0.05）。此外,转染IL-15过表达慢病毒可使G1期细胞比例显著下降,S期和G2/M期细胞比例显著升高（P<0.05）。【结论】在正常生理条件下,IL-15是定位在细胞内并发挥作用的,IL-15过表达对猪骨骼肌成肌细胞早期凋亡没有显著影响,但可以抑制其晚期凋亡,并促进细胞增殖。这一研究将为IL-15正向调控猪骨骼肌肌肉品质和治疗相关肌肉疾病提供技术和理论依据。