青贮玉米植株剪切力学特性试验研究

为获得青贮玉米植株机械化收获时切碎揉搓过程的剪切力学特性,以云南地区广泛种植的路单20号、曲辰9号和红单10号青贮玉米植株为试验对象,使用万能试验机进行植株的径向剪切试验。通过试验测得青贮玉米秸秆剪切破坏力为680.38~1 613.75 N,抗剪强度为1.04~2.78 MPa;青贮玉米果穗剪切破坏力为585.91~938.47 N,抗剪强度为0.29~1.10 MPa。结果表明,在相同的加载速度下,秸秆的径向剪切破坏力和抗剪强度都随着取样高度的增加而减小。果穗的径向剪切破坏力和抗剪强度都随着果穗根部位置的增加而减小。在剪切部位相同时,秸秆和果穗的径向剪切破坏力及抗剪强度都随加载速度的增加而减小。     

Razor blade shear method for evaluating duck breast meat and tendon texture

Ducks are a small but important portion of the US poultry industry, and are a much larger proportion of the poultry markets in other countries. More duck meat fillet products enter the further processing market, yet few studies have been conducted on meat quality characteristics. Therefore, this project was conducted to determine the effects of sex, bird size, and marination treatment on breast (pectoralis major) fillet weight, cook yield, and Warner-Bratzler (WB) shear values. Razor shear was also used to isolate connective tissue in the breast meat that is typically responsible for consumer complaints regarding toughness. Ducks were identified at 1 d of age for sex, processed at 35 d of age in a commercial facility, and carcasses were categorized as small (1.6 kg), medium (2.0 kg), or large (2.5 kg). Breast fillets (120, 20 each from 2 sexes and 3 sizes) were divided and 60 were marinated using vacuum tumbling whereas 60 were left unmarinated. All of the fillets were then weighed, cooked, and reweighed to determine cook yield. Razor shear was conducted on 2 areas within each fillet and another 2 razor shear measurements were taken on each fillet directly through the connective tissue near the wing insertion. A section of each fillet was then removed for a 2-slice WB shear. Carcass size from small to large corresponded to an increase in raw fillet weight. Fillets from males required more razor shear force than fillets from females. Marination improved cook yield and reduced both the WB shear values and the razor shear values for the meat and the tendon. The razor shear method was effective at measuring both duck meat texture and tendon toughness.     

Clinical findings and treatment of shear mouth in two horses associated with ipsilateral painful dental disease

Shear mouth is a rare and poorly described dental condition observed in horses. This report outlines 2 cases of unilateral shear mouth with ipsilateral painful dental disease. Both cases are young horses diagnosed with idiopathic 409 cheek tooth fractures associated with shear angles on the 100 and 400 cheek teeth rows. Corrective odontoplasty was performed in both cases to correct the cheek tooth occlusal surface angle following exodontia of the diseased molars.     

Shear mouth secondary to temporohyoid osteoarthropathy

Temporohyoid osteoarthropathy (THO) is a progressive disease of unknown aetiology that can result in pain during normal movement of the tongue and larynx during mastication and deglutition. Shear mouth is a rare, poorly described condition, which may be associated with painful dental disease. This report describes a case of shear mouth attributable to THO. The THO was surgically treated by undertaking a left-sided ceratohyoidectomy (CHO) and the shear mouth resolved over the course of 18 months.     

TMEM219基因可变剪切体相对表达量及其对鹿茸重量的影响

试验旨在研究TMEM219基因3种剪切体在不同重量鹿茸尖端的表达规律及TMEM219基因表达对鹿茸重量的影响,以期探究TMEM219基因对鹿茸生长发育的调控机理。利用实时荧光定量PCR技术对TMEM219基因及其3种剪切体在同一重量组鹿茸的不同组织及不同重量组鹿茸的同一组织mRNA的相对表达水平进行检测,同时测定并比较不同产茸量梅花鹿的血清中胰岛素生长因子1（IGF-1）和胰岛素样生长因子结合蛋白3（IGFBP-3）的浓度。结果表明,TMEM219基因的3种剪接体在梅花鹿鹿茸的间充质及前成软骨组织（RP）、过渡组织（TZ）及软骨组织（C）中均有表达,TMEM219-918基因相对表达量极显著高于TMEM219-1005与TMEM219-1960基因（P<0.01）,TMEM219-1005与TMEM219-1960基因相对表达量无显著差异（P>0.05）;高重量组TMEM219基因表达量显著高于低重量组（P<0.05）;同时,高重量组个体血清中IGF-1浓度显著高于低重量组个体（P<0.05）,而IGFBP-3浓度显著低于低重量组个体（P<0.05）。结果提示,TMEM219基因高表达可能会促进鹿茸的生长,增加鹿茸重量;推测其可能的机理是TMEM219竞争性结合IGFBP-3,减少与其结合的IGF-1,加强IGF-1与IGF-1R的亲和力,进而提高IGF-1对鹿茸生长的促进作用。TMEM219基因可能成为影响鹿茸生长发育的候选基因,为提高鹿茸生长提供理论基础。     

甘南牦牛肉成熟过程中剪切力、钙激活酶变化规律分析

为研究甘南地方牦牛肉品质对甘南牦牛肉成熟过程中剪切力和Calpains活性的变化规律进行测定与分析,结果表明:牦牛肉在排酸嫩化过程中剪切力、钙激活酶呈现规律性变化,刚宰后到宰后第2天剪切力逐渐上升到最大值6.14kg,之后逐渐降低,宰后第4d降至4.82kg。宰后当天即开始排酸,第3～4d基本完成酸成熟过程,第1～9d钙激活酶光密度值由不足0.1逐渐提升到近0.7,说明整个成熟过程钙激酶的活性呈现下降的趋势。     

Application and optimization of the tenderization of pig Longissimus dorsi muscle by adenosine 5'‐monophosphate (AMP) using the response surface methodology

Based on single factor experiments, NaCl concentration, adenosine 5'‐monophosphate (AMP) concentration and temperature were selected as independent variables for a three‐level Box‐Behnken experimental design, and the shear force and cooking loss were response values for regression analysis. According to the statistical models, it showed that all independent variables had significant effects on shear force and cooking loss, and optimal values were at the NaCl concentration of 4.15%, AMP concentration of 22.27 mmol/L and temperature of 16.70°C, which was determined with three‐dimensional response surface diagrams and contour plots. Under this condition, the observed shear force and cooking loss were 0.625 kg and 8.07%, respectively, exhibiting a good agreement with their predicted values, showing the good applicability and feasibility of response surface methodology (RSM) for improving pork tenderness. Compared with control pig muscles, AMP combined with NaCl treatment demonstrated significant effects on improvement of meat tenderness and reduction of cooking loss. Therefore, AMP could be regarded as an effective tenderization agent for pork.     

Associations between candidate SNPs in the calpain 1, calpastatin and leptin genes and meat tenderness among Swedish beef populations

Abstract

The contribution of three candidate genes to the variation in meat tenderness was tested in muscle samples from 243 pure-bred, young, beef bulls of Angus, Charolais, Hereford, Limousin and Simmental breeds, raised in Swedish commercial herds. The animals were genotyped for single nucleotide polymorphisms (SNPs) in the calpain 1 (CAPN1), calpastatin (CAST) and leptin genes. The frequent calpain 1 CAPN1:c.947G>C G allele showed an unfavourable association with tenderness. The calpastatin CAST:c.155C>T T allele, which was the most common allele, showed a favourable association with Warner–Bratzler shear force (WBSF) and compression tests. An association was observed between the leptin UASMS2C>T SNP and compression tests.     

Tenderization potential of Hanwoo beef muscles from carcasses with differed genders and loin intramuscular fat content levels during post mortem ageing

Carcasses from Hanwoo steers (n = 15) and cows (n = 15) were classified into three groups: group 1 (G1), the carcasses had 10% to < 11.5% intramuscular fat (IMF) in loin muscles; group 2 (G2), the carcasses had 13% to < 14.5% IMF in loin muscles; and group 3(G3), the carcasses had 17% to < 18.5% IMF in loin muscles. These were used to evaluate the effects of gender and carcass group on quality traits and Warner–Bratzler shear force (WBSF) of Psoas major (PM), Longissimus thoracis (LT), Longissimus lumborum (LL), Longus colli (LC), Supraspinatus (SS), Latissimus dorsi (LAD), Semimembranosus (SM), Quadriceps femoris (QF), Biceps femoris (BF) and Semitendinosus (ST) muscles. Our results showed that pH values of LT, LL, LC, BF and QF muscles were lower in steers than in cows (P < 0.05). Water holding capacity (WHC) was found higher in LC, SS, LAD and QF muscles of steers (P < 0.05). At day 2 of ageing, gender affected the WBSF values of only PM, LD and QF muscles in G1, and QF muscle in G3; however, with additional ageing, the gender effect was observed for most of the muscles. Most muscles showed ageing responses; however, the rates of ageing response significantly varied depending on gender and carcass groups. The muscles of G1 and G2 had generally higher tenderization potentials than those of G3. Furthermore, most muscles in G3 had generally lower WBSF values than in G1 and G2. These results clearly indicate that ageing has a significant effect on quality and WBSF of beef muscles, and the classification by loin IMF level may be useful for prediction of the tenderness of other muscles.     

Effects of low protein diet and low protein diet supplemented with synthetic essential amino acids on meat quality of broiler chickens

We investigated the effects of a low crude protein (CP) diet and a low CP diet supplemented with synthetic essential amino acids (EAA) on the meat quality of broiler chickens. Twenty‐one‐day‐old chickens were assigned to one of three diets: control, low CP (LCP), or low CP supplemented with EAA (ELCP). The chickens received these diets for 10 days. The shear force value (SFV) and free glutamate content of the Pectoralis major muscle were measured as indicators of the meat toughness and taste. The collagen and crude fat content of the muscle and the cross‐sectional area of myofibers were measured to evaluate the effects of the LCP and ELCP diets on meat toughness. The SFV of the ELCP group was 47% lower than that of the control group (P < 0.01). However, the LCP diet did not affect the SFV. The collagen and crude fat content were not affected by the dietary treatment. The cross‐sectional area was lower in the LCP and ELCP groups (P < 0.05) than the control group. The free glutamate content of muscle was not affected by the dietary treatment. Thus, a low CP diet supplemented with EAA is an effective means of producing tender meat.     

Early post mortem expression of genes related to tenderization in two Italian Simmental young bulls' skeletal muscles differing in contractile type

The early post mortem expression of eight genes potentially involved in meat ageing process and the tenderness of two Italian Simmental young bulls' (Bos taurus) skeletal muscles differing in their contractile type were evaluated. Samples of Longissimus lumborum (LL) and Infraspinatus (IS) muscles were collected from 17 bulls. The messenger RNA (mRNA) abundances of calpain‐1, calpain‐2, calpastatin, caspase 3, caspase 9, heat shock protein 27 (Hsp27), Hsp40 and Hsp70 were detected by quantitative PCR. The myosin heavy chain‐slow and ‐fast isoform content, the pH_48h and the lipid content of the muscles were in line with the contractile and metabolic type. In comparison with the fast LL, the slow IS showed a lower calpain‐1/calpastatin mRNA content ratio after slaughtering and a higher Warner‐Bratzler Initial Yield value after 7 days of ageing. Hsp27 and Hsp70 mRNA abundances were significantly lower in LL than IS, highlighting their potential role in the ageing process of bovine muscles.     

Meat quality of fully or partly outdoor reared pigs in organic production

Abstract

Outdoor production on pasture is considered an option in organic pig production. The aim of the present trial was to study the influence of feeding strategies combining outdoor and indoor rearing on pig meat quality. The experiment was carried out with 245 pigs in 5 replicates, and commenced following weaning at day 52. Five treatments were compared: 1) pigs fed ad libitum and reared indoors with access to an outdoor concrete area (In-A); 2) pigs fed restrictively on pasture until 40 kg body weight and then kept indoors with access to an outdoor concrete area and fed ad libitum until slaughter (In-40A); 3) pigs fed restrictively on pasture until 80 kg body weight and then kept indoors with access to an outdoor concrete area and fed ad libitum until slaughter (In-80A); 4) pigs reared on pasture and fed restrictively during the whole period of growth (Out-R); and 5) pigs reared on pasture and fed ad libitum during the whole period of growth (Out-A). All pigs had free access to roughage (clover-grass silage/fresh clover grass). Restrictive feeding in the weight range from weaning to 40 kg body weight (In-40A) resulted in a reduced daily gain; however, following transfer to indoor facilities and ad libitum feeding these pigs compensated in growth and the overall daily gain did not differ from the In-A control pigs. Pigs fed restrictively from weaning to 80 kg body weight were unable to compensate completely following transfer to indoor facilities. Out-R pigs had the lowest overall daily gain, while In-A pigs and Out-A pigs had similar daily gain. Meat quality assessments were performed on longissimus dorsi (LD) samples from a subsample of 100 pigs (2 castrates and 2 female pigs from each treatment in each replicate). Compared to meat from either ad libitum treatments (In-A and Out-A), meat from Out-R and In-80A pigs was less red due to a lower pigmentation, and had a higher ratio of polyunsaturated:saturated fatty acids. In addition, Out-R female pigs had numerically (6–10 Newton) higher shear force than In-A and Out-A. Treatments did not affect the concentration of α-tocopherol of meat. Introducing a finishing period with free access to concentrates following 40 kg body weight until slaughter prevented the deterioration in meat quality. However, a finishing period following 80 kg body weight was not sufficient. In conclusion, ad libitum feeding in the organic production system gave superior meat quality compared to a restrictive feeding strategy. However, including a finishing period indoors with ad libitum feeding of concentrates may prevent the detrimental effect of restrictive feeding on meat quality.     

Effects of transportation during the hot season,breed and electrical stimulation on histochemical and meat quality characteristics of goat longissimus muscle

The effects of transportation and electrical stimulation (90 V) on physiological, histochemical and meat quality characteristics of two breeds of Omani goats were assessed. Twenty 1‐year‐old male goats from each breed (Batina and Dhofari) were divided into two groups: 3 h transported during the hot season (42°C day time temperature) and non‐transported. Animals were blood‐sampled before loading and prior to slaughter. Electrical stimulation was applied 20 min postmortem to 50% randomly selected carcasses of both breeds. Temperature and pH decline of the Longissimus was monitored. Ultimate pH, shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and colour were measured from samples of Longissimus dorsi muscles. Electrical stimulation and transportation had a significant effect on most biochemical and meat quality characteristics of Longissimus dorsi. The transported goats had higher plasma cortisol (P < 0.01), adrenaline, nor‐adrenaline and dopamine concentrations (P < 0.05) than non‐transported goats. Electrical stimulation resulted in a significantly (P < 0.05) more rapid muscle pH fall during the first 12 h after slaughter. Muscles from electrically‐stimulated carcasses had significantly (P < 0.05) longer sarcomeres, lower shear force value, a lighter colour (higher L* value), higher expressed juice and myofibrillar fragmentation index than those from non‐stimulated ones. Meat from transported goats had significantly higher pH, expressed juice and shear force, but contained significantly lower sarcomere length and L* values than non‐transported goats. The proportion of the myosin ATPase staining did not change as a function of stimulation, transportation or breed. These results indicated that subjecting goats to transportation for 3 h under high ambient temperatures can generate major physiological and muscle metabolism responses. Electrical stimulation improved quality characteristics of meat from both groups. This indicates that electrical stimulation may reduce detrimental effects of transportation on meat quality of Omani goats.     

Effects of extended postmortem aging and intramuscular location on protein degradation,muscle fiber morphometrics,and tenderness of beef longissimus lumborum and semitendinosus steaks

The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into five locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1 °C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and day-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than day 56 and 112 (P < 0.01), which did not differ (P = 0.53). In the LL, day-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and day-28 steaks had greater (P < 0.01) WBSF values than day-112 steaks. Degraded ST 38-kDa DES content was less on day 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than day 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on day 7 than day 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.     

中国西门塔尔牛肌肉肌纤维类型和肉品质特性研究

为研究中国西门塔尔牛的肌纤维和肉品质特性,本试验以10头中国西门塔尔公牛为研究对象,测定了背最长肌、腰大肌和半腱肌的组织学特性、pH、系水力、剪切力和质构剖面分析。结果显示,肌纤维直径Ⅰ型 < ⅡA型 < ⅡB型,腰大肌中Ⅰ型具有最高的肌纤维数比例和肌纤维面积比,背最长肌和半腱肌中ⅡB型具有最高的肌纤维比例和肌纤维面积比。与腰大肌相比,背最长肌和半腱肌具有较低pH、弹性和压力失水率,较高的剪切力、硬度和回复性。综上所述,肌纤维特性影响牛肉品质,特别是牛肉的质构特性,提高Ⅰ型纤维比例和降低ⅡB型纤维比例能够改善牛肉嫩度。     

Seismic behaviors of shear wall with concrete filled round steel tube columns and concealed bracing

提出了圆钢管混凝土边框内藏桁架剪力墙结构.该新型剪力墙包含2种组合:不同受力体系(钢管混凝土、钢桁架与剪力墙)组合和不同材料(型钢与混凝土)组合,形成了多重组合剪力墙.进行了3个1/5缩尺中高剪力墙的低周反复荷载试验.在试验研究基础上,对比分析了剪力墙的承载力、延性、刚度及其衰减过程、滞回特性、耗能能力及破坏特征,建立了圆钢管混凝土边框内藏桁架剪力墙的承载力计算模型,计算结果与实测结果符合较好.研究表明:圆钢管混凝土边框内藏桁架剪力墙与普通剪力墙相比抗震性能显著提高.     

种草和施用聚丙烯酰胺对荒坡紫色土抗剪和抗蚀性能的影响研究

为探究种植草类和施用聚丙烯酰胺(PAM)对荒坡紫色土抗侵蚀性的影响,尤其是对其抗剪和抗蚀性能的影响,选取狗牙根和三叶草进行盆栽试验,设计了对照、单植草类、单施PAM和复合措施(“草类+PAM”)4类处理开展研究,测定了根系指标和土壤理化性状指标,计算了土壤的抗剪强度指标和抗蚀性指标。结果表明,狗牙根和三叶草根系均能显著降低土壤容重、提高土壤孔隙度和有机质含量(P<0.05),有效增强土壤的抗剪和抗蚀性能;施加PAM能有效促进上述草类各径级根系的生长,显著改善土壤的微结构(P<0.05),尤其是非毛管孔隙度(单施PAM为CK的1.15~1.31倍),提高土体抗剪强度及内摩擦角φ,增大粒径>0.25 mm、>0.5 mm的水稳性团聚体含量、平均重量直径和几何平均直径等抗蚀性指标;PAM对荒坡紫色土抗剪和抗蚀性能的增强效果存在最优浓度;草类根系对土壤抗剪性能的影响较抗蚀性能明显,能显著提高土体的抗剪性能(P<0.05),尤其是增大土壤粘聚力;PAM对土壤抗蚀性能的影响较抗剪性能明显,能显著促进土壤团聚体大颗粒的形成和小颗粒的减少,显著提高土壤团聚度和改善土壤团聚结构等(P<0.05);较单一措施,“草类+PAM”对荒坡紫色土抗剪和抗蚀性能的增强效果最为明显,其中狗牙根与30 g·m^-3的PAM混施时效果最优;0相似文献   

Study on Muscle Fiber Types and Meat Quality Traits of Chinese Simmental Cattle

The aim of this test was to study muscle fiber characteristics and meat quality traits of Chinese Simmental cattle.Ten Chinese Simmental bulls were selected and longissimus dorsi,psoas major and semitendinosus were collected.Histological characteristics,pH,water holding capacity,shear force and texture profile analysis (TPA) were measured.The results showed that the diameter of these muscle fibers increased in the rank order type Ⅰ < ⅡA < ⅡB.The number and area percentage of type Ⅰ muscle fiber were highest in longissimus dorsi and that of ⅡB muscle fiber was highest in psoas major and semitendinosus.Longissimus dorsi and semitendinosus had lower pH,springiness,pressing lossing rate and higher shear force,hardness and resilience comparing with psoas major.In conclusion,muscle fiber characteristics could affect meat quality,especially textural properties of Chinese Simmental bulls.Increasing the percentage of type Ⅰ muscle fiber and decreasing ⅡB type could improve beef tenderness.