生猪屠宰中击昏电压对猪肉品质的影响

国内外对于生猪屠宰致晕方法已经做过大量的研究,但总体来讲,在同一体系下的成批量的比较涉及较少。该文选用60头品种、年龄、性别相同的杜大长三元杂交猪(体重100 kg±5 kg,)随机分成3组,每组20头,分别用电压90 V、110 V、130 V,电流2.4~2.8A,在头部进行电击昏后屠宰。结果表明,90 V、110 V电击昏组放血量占活体重量比显著高于130 V电击组。取背最长肌测定各项肉质指标,结果显示:宰后0.75 h,采用130 V和110 V电压电击昏组的猪肉p H值与90 V电压组差异显著(p0.05),其它时间点不同电压电击组差异不显著;击昏电压对宰后背最长肌的色泽(L*和a*值)、滴水损失、蒸煮损失、嫩度无显著影响(p0.05)。生产中建议击昏电压采用110 V,以最大程度实现猪肉品质的改良。     

三段冷却方式对淘汰奶牛背最长肌宰后生化变化和嫩度的影响

分别取淘汰奶牛的左侧背最长肌,在2℃冷却24h作为对照组;右侧背最长肌在2℃冷却3h,15℃冷却6h,然后在2℃冷却15h(三段冷却方式),作为处理组。测定结果显示,对照组的肌肉中心温度宰后10h时已降至4.1℃,处理组肌肉中心温度在宰后3⁹h维持在(16±0.5)℃范围内,到宰后13.5h降到4℃。处理组宰后8和24h的肌糖原含量显著低于对照组,宰后8h处理组的pH值显著低于对照组。这一结果表明,宰后4h开始处理组的肌糖原分解速度快于对照组,从而加快宰后处理组pH值的降低速度。处理组宰后8,24,48h的肌节长度显著大于对照组,宰后1和3d的剪切力值显著低于对照组。这一结果提示,淘汰奶牛宰后在2℃持续冷却,可能导致背最长肌的严重冷收缩,从而对嫩度产生负面影响,三段冷却方式可以改善淘汰奶牛宰后嫩度品质。     

长白猪胴体性能及不同部位肌肉品质研究

研究测定了长白猪胴体性能肉质性状及背最长肌、腰大肌及后腿肉氨基酸、脂肪酸含量。结果表明,长白猪胴体性能较高,肉质良好。屠宰体重105.15 kg,胴体瘦肉率69.55%,肉色3.38分、大理石纹评分3.30分,pH值6.14,肌内脂肪2.93%。每100 g背最长肌、腰大肌及后腿肉的17种氨基酸含量、氨基酸总量、鲜味氨基酸含量和必需氨基酸含量都以背最长肌最高,其次是腰大肌,后腿肉最低。鲜味氨基酸占氨基酸总量比例以后腿肉最高为79.13%,比背最长肌和腰大肌分别提高1.03%(P<0.01)和0.69%(P<0.01);必需氨基酸占氨基酸总量比例以腰大肌最高为41.23%,分别比背最长肌和后腿肉提高2.15%(P<0.05)和1.29%(P>0.05)。棕榈酸、硬脂酸、油酸和亚油酸四种脂肪酸含量3个部位间差异不显著。肌内脂肪以后腿肉含量最高,分别比背最长肌和腰大肌提高47.86%(P<0.05)、57.27%(P<0.05);肌肉蛋白质和干物质含量以背最长肌最高,分别比腰大肌和后腿肉提高7.08%(P<0.01)、6.82%(P<0.01)、11.22%(P<0.01)、5.92%(P<0.01)。     

猪宰后不同部位PSE肉与正常肉蛋白质变化的比较

为了研究猪宰后不同部位PSE肉与正常肉的蛋白质变化,为猪肉品质调控与PSE肉形成的研究提供参考,选取宰后背最长肌、股二头肌均为正常肉或PSE肉的175日龄"杜长大"阉公猪各6头,测定24 h内肌肉的pH值、离心失水率、蛋白质溶解度、钙蛋白酶活性及SDS-PAGE分析。结果表明:背最长肌正常肉的总蛋白溶解度显著高于PSE肉的总蛋白溶解度(P0.05),PSE肉肌浆蛋白溶解度24 h内变化不显著(P0.05),背最长肌正常肉的肌原纤维蛋白溶解度高于PSE肉;宰后0 h,股二头肌的钙蛋白酶活性显著高于背最长肌(P0.05),宰后8 h内正常肉的钙蛋白酶活性显著高于PSE肉(P0.05);正常肉与PSE肉的肌原纤维蛋白SDS-PAGE条带差异较大,肌浆蛋白SDS-PAGE差异不明显。结果提示:PSE肉与正常肉蛋白的变化差异主要在于肌原纤维蛋白,且股二头肌与背最长肌相比肌原纤维蛋白分解快;不同部位正常肉与PSE肉肌浆蛋白无明显降解。     

击晕屠宰对肉牛血液理化指标和肉品质的影响

为了研究击晕屠宰对肉牛血液理化指标和肉品质的影响,试验选取12头西门塔尔公牛随机分为试验组(击晕屠宰)和对照组(非击晕屠宰),宰时采血,宰后排酸72 h后测定肉品质。结果表明:试验组血液中皮质醇、ACTH浓度、肌酸激酶与乳酸含量显著低于对照组(P0.05);肌肉宰后45分钟、4小时、24小时p H值显著低于对照组(P0.05);成熟72 h后试验组的背最长肌剪切力、汁液损失率、压力失水率、黄度值均显著低于对照组(P0.05);试验组的亮度值显著高于对照组(P0.05);试验组背最长肌肌纤维面积显著低于对照组(P0.05),肌纤维密度显著高于对照组(P0.05)。说明击晕屠宰能够显著缓解肉牛的宰前应激,有助于改善肉品质。     

品种和体重对猪肌肉生长抑制素表达的影响

本文旨在研究猪的体重和品种对其背最长肌的肌肉生长抑制素基因表达的影响,并对猪100kg时的胴体性状与肌肉肌肉生长抑制素基因表达量的相关性进行分析。试验采用荧光定量PCR方法,以β-actin基因为内标,研究不同体重(20、50和100kg)和品种(汉普夏猪和长白×撒坝猪)对猪背最长肌的肌肉生长抑制素基因表达的影响,同时考察试验猪在100kg时的胴体肉质指标。结果表明:①猪背最长肌中肌肉生长抑制素的表达随体重的增加呈上升的趋势(P>0.05);②相同体重条件下长撒猪背最长肌中肌肉生长抑制素表达均显著高于汉普夏猪(P<0.05),其中20kg时达到极显著水平(P<0.01);③肌肉生长抑制素的表达与瘦肉率呈极显著的负相关(P<0.01),与背膘厚则呈极显著的正相关(P<0.01),与滴水损失和肌内脂肪的相关性不显著(P>0.05)。本研究结果表明猪背最长肌的肌肉生长抑制素基因的表达量随体重增加而提高,品种间差异显著,并且肌肉生长抑制素基因的表达与瘦肉率、背膘厚存在显著的相关性。     

专门化品系ZFY猪生长性能、胴体性能及不同部位肌肉品质研究

研究测定了专门化品系ZFY猪肥育性能、胴体性能、肉质性状及背最长肌、腰大肌、后腿肉氨基酸、脂肪酸含量。结果表明,ZFY系猪30—100kg日增重818．87g,料重比2．40;胴体性能较高,肉质良好,屠宰体重103．43kg,胴体瘦肉率67．75％,肉色3．45、大理石纹3．45,pH6．60,肌内脂肪1．55％。每100g背最长肌、腰大肌及后腿肉的氨基酸总量和鲜味氨基酸含量都以背最长肌最高,分别比腰大肌和后腿肉提高2．70％（P〉0．05）和1．95％（P〉0．05）、1．03％（P〉0．05）和1．66％（P〉0．05）;必需氨基酸含量、鲜味氨基酸和必需氨基酸分别占氨基酸总量比例都以腰大肌最高,分别比背最长肌和后腿肉提高0．19％（P〉0．05）和0．66％（P〉0．05）、1．79％（P〉0．05）和1．50％（P〉0．05）、2．85％（P〉0．05）和1．42％（P〉0．05）。棕榈酸、硬脂酸、油酸和亚油酸4种脂肪酸含量3个部位间差异不显著。肌肉脂肪以后腿肉含量最高,分别比背最长肌和腰大肌提高91．94％（P〈0．05）、112．5％（P〈0．05）;肌肉蛋白质含量以腰大肌最高,分别比背最长肌和后腿肉提高0．22％（P〉0．05）、1．64％（P〉0．05）;肌肉干物质含量以后腿肉最高,比背最长肌和腰大肌分别提高5．19％（P〉0．05）、4．67％（P〉0．05）。     

不同品种牛背最长肌抗氧化性能的研究

本试验旨在研究不同品种牛肌肉的抗氧化特性,为优质牛肉的生产提供试验数据。选用5个品种牛(利木赞牛、中国西门塔尔牛、鲁西牛、秦川牛、晋南牛)的背最长肌,测定肌内脂肪含量、24小时的滴水损失以及在0～4℃下肉色、过氧化物值(PV)及硫代巴比妥酸反应物(TBARS)在72h内的变化动态。结果表明,背最长肌的肌内脂肪含量与24小时滴水损失率在不同品种牛肌肉之间没有显著差异(P>0.05);在整个储存时期(0～72h),5个品种牛肌肉的a*、b*值均呈下降趋势;4～72h内,利木赞牛肌肉的a*值均是最高的,且在冷藏8、12h时,利木赞牛肌肉的a*值显著大于鲁西牛肉和秦川牛(P<0.05),24h后利木赞牛的a*值显著大于西门塔尔牛(P<0.05);随着储存时间的延长,5个品种牛背最长肌的PV和TBARS值均有不同程度的增加,利木赞牛肌肉的PV和TBARS值增加最慢,秦川牛和鲁西牛肌肉的PV和TBARS值增加较快。结果表明,5个品种牛的肌内脂肪含量和滴水损失差异不显著,利木赞牛肌肉能够较长时间保持肉色和抗氧化特性。     

白藜芦醇对生长肥育期宁乡猪肉品质的影响

本试验旨在研究饲粮中添加白藜芦醇对生长肥育期宁乡猪肉品质的影响。选用体重(43±1) kg的宁乡猪24头,随机分为2个组,每组6个重复,每个重复2头(公母各占1/2)。对照(CON)组饲喂基础饲粮,白藜芦醇(RES)组饲喂在基础饲粮中添加300 mg/kg白藜芦醇的试验饲粮。试验期80 d。饲养结束后,每栏取1头体重接近平均体重的猪进行屠宰,并采集背最长肌、股二头肌及腰大肌样品,用于肉品质指标检测。结果表明:1)饲粮中添加白藜芦醇对宁乡猪的生长性能和肌肉主要营养成分含量均无显著影响(P0.05)。2)与对照组相比,白藜芦醇组宁乡猪宰后24 h背最长肌的红度(a~*)显著提高(P0.05),宰后24 h背最长肌和股二头肌的黄度(b~*)有降低趋势(0.05≤P0.10)。3)与对照组相比,白藜芦醇组宁乡猪背最长肌的磷酸果糖激酶(PFK)活性极显著降低(P0.01),股二头肌的丙酮酸激酶(PK)活性和乳酸(LA)含量显著降低(P0.05);肌肉pH无显著变化(P0.05)。4)与对照组相比,白藜芦醇组宁乡猪背最长肌的谷胱甘肽过氧化物酶(GSH-Px)活性、总抗氧化能力(T-AOC)及股二头肌的GSH-Px活性均极显著提高(P0.01),股二头肌的丙二醛(MDA)含量极显著降低(P0.01)。由此可见,饲粮中添加白藜芦醇可以提高宁乡猪肌肉的抗氧化能力,降低宰后肌肉的糖酵解速率,对肉品质具有一定的改善作用。     

一水肌酸对肥育猪胴体组成及肌肉系水力的影响

本研究旨在观察一水肌酸(creatine monohydration,CMH)对肥育猪生长性能、胴体组成和系水力的影响及其机理探讨。选用体重70 kg左右的杜长大三元杂交猪48头,按试验要求随机分为2组,每组设3个重复,每个重复8头猪,分别饲喂含CMH为0或0.25%的日粮,饲养试验时间为30 d。结果发现,CMH对猪日增重无显著影响(P>0.05);CMH显著提高了肥育猪的眼肌面积(P<0.05),而对屠宰率、瘦肉率、胴体直长、胴体斜长、腹脂重、脂肪率、背膘厚、皮肤比率、骨骼比率等无显著影响(P>0.05);CMH还使试验组猪的背最长肌率显著提高(P<0.05),股二头肌率有提高趋势但差异不显著,而对其他骨骼肌重率无明显影响(P>0.05);CMH使肥育猪宰后24 h背最长肌和半膜肌的滴水损失明显降低(P<0.05)、pH显著提高(P<0.05),而肌肉中乳酸含量显著降低(P<0.05)。结果提示,饲料中添加一水肌酸可通过降低肌肉中乳酸的积累,提高肌肉的pH,从而降低宰后肌肉的滴水损失,改善肉质。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein