热处理对牛、羊、猪肉肌内脂肪过氧化程度影响

为分析不同热处理方式对动物肌肉脂肪过氧化程度的影响,采用硫代巴比妥酸比色法测定热处理后3种肉肌内脂肪过氧化反应终产物丙二醛生成量,气相色谱-质谱联用法、索氏抽提法测定其肌间脂肪的脂肪酸组成和肌内脂肪含量,并用扫描电镜观察3种肉的肌纤维形貌研究炒、蒸、烤三种不同热处理方式对牛、羊、猪肉肌内脂肪过氧化程度的影响。结果表明:炒制后羊肉肌内脂肪中MDA含量显著高于牛、猪肉(P0.05),蒸煮后牛、羊肉肌内脂肪中MDA含量高于猪肉(P0.05),烤制后牛肉肌内脂肪中MDA含量显著高于羊、猪肉(P0.05);牛、羊、猪肉肌内饱和脂肪酸(SFA)相对含量依次为52.60、38.49、39.81g/100g;单不饱和脂肪酸(MUFA)含量依次为56.61、54.63、44.73g/100g;多不饱和脂肪酸依次为2.70、4.90、5.56g/100g;猪肉肌内脂肪含量(30.03g/100g)显著高于牛、羊肉(P0.05),羊肉肌内脂肪含量(20.48g/100g)显著高于牛肉(8.31g/100g)(P0.05);牛和羊肌纤维排列方向一致,结构紧密,猪肌纤维排列结构则较为松散。热处理温度是影响脂质过氧化程度大小的主要因素,肌纤维排列结构影响肌内脂肪过氧化产物MDA的含量。     

羊肉肌内脂肪及影响因素的研究进展

随着人们消费理念的转变和对羊肉营养价值的认识,羊肉的市场需求量日益增加,而人们对羊肉品质的要求也越来越高.在众多影响羊肉品质的因素中,肌内脂肪是重要因素之一.羊肌肉脂肪包括肌间脂肪和肌内脂肪(IMF),肌间脂肪通常存在于肌外膜上,主要成分为三酰甘油;而肌内脂肪则均匀分布于肌肉中,存在于肌束膜和肌内膜上[1],与膜蛋白紧密结合在一起,其主要成分为磷脂,是影响肌肉风味的重要前体物[2].     

肉鸡肌内脂肪沉积的研究进展

肌肉脂肪分为肌间脂肪和肌内脂肪,肌内脂肪影响着肉质的嫩度、系水力、剪切力值等。一般来说,肌内脂肪含量高,肌肉肉质细嫩,口感好。肌内脂肪的调控机制很复杂,受营养、环境和基因等因素的影响,其中营养调控和基因调控是改善鸡肌内脂肪沉积的根本途径。文章综述了鸡肌内脂肪的形成及营养和基因对其调控作用和机制的研究进展。     

肌内脂肪含量和脂肪酸组成对绵羊肉品质的影响

肌内脂肪含量的高低和氨基酸的组成对绵羊肉品质的相关性状具有广泛影响。然而,不同品种以及同一品种不同部位的肌肉之间肌内脂肪的含量和氨基酸的组成也在存在着明显的差异。另外,肌内脂肪的含量也随着绵羊的性别、年龄、体重和饲养方式的不同而变化。这就意味着,在不考虑遗传因素的情况下,通过改变饲养方式和日粮的组成可以改善羊肉肌内脂肪含量。因此,本文从这一角度出发,阐述了肌内脂肪含量和氨基酸组成与绵羊肉品质的关系,并针对改善绵羊肌内脂肪含量的调控技术进行了综述。     

猪肌内脂肪的研究进展

猪肌内脂肪的含量是影响猪肉品质的一个重要因素,它影响着肉的嫩度、系水力、剪切力值、风味和多汁性。猪肉肌内脂肪的调控机制很复杂,主要受营养、环境和基因等多个方面的影响,其中,营养调控和基因调控是改善猪肌内脂肪沉积的根本途径。综述了猪肌内脂肪的形成以及营养和基因对其调控作用和机制的研究进展。     

猪肌内脂肪调控相关基因的研究进展

脂肪不仅是动物能量的主要来源,而且还与肉品的风味品质及食用价值有很大的关系.猪肌内脂肪的含量是影响猪肉品质的一个重要因素,它影响肉的嫩度、系水力、剪切力值、风味和多汁性.肌内脂肪的沉积受多种因素的影响,包括遗传、营养、环境等因素.该文首先介绍肌内脂肪对猪肉品质的影响,其次,再从基因水平阐述各种基因对肌内脂肪调控的相关研究进展,以期通过调控肌内脂肪含量获得更高品质的猪肉产品.     

猪肌内脂肪的研究进展

猪肌内脂肪的含量是影响猪肉品质的一个重要因素,它影响着肉的嫩度、系水力、剪切力值、风味和多汁性.猪肉肌内脂肪的调控机制很复杂,主要受营养、环境和基因等多个方面的影响,其中,营养调控和基因调控是改善猪肌内脂肪沉积的根本途径.综述了猪肌内脂肪的形成以及营养和基因对其调控作用和机制的研究进展.     

牛肉肌内脂肪日粮营养调控技术的研究进展

牛肉是一种营养价值较高的食品,具有高蛋白、低脂肪、低胆固醇等优点。随着人们对健康和保健意识的提高,消费者越来越意识到健康和饮食的关系,要求吃到高质量的牛肉。肌内脂肪是影响牛肉品质的重要因素之一,影响牛肉的多汁性、嫩度和风味,适宜的肌内脂肪含量可以改善肉质,提高牛肉的营养价值和食用品质。肌内脂肪的含量和分布受遗传和营养等多种因素的控制和影响,通过营养调控干预机体代谢来改善肌内脂肪是一种切实可行的途径。文章仅就肌内脂肪与牛肉感官品质、营养及保健价值的关系和国内外通过日粮营养调控改善牛肉肌内脂肪含量,提高牛肉质量的技术研究作一综述。     

影响绵羊肉质因素的研究进展北大核心

羊肉作为人类膳食优质蛋白质来源,消费者对其品质要求越来越高。肉品质包括肉色、风味、嫩度、肌内脂肪含量等指标,其受营养和遗传等多种因素影响。嫩度是感知肉类食用质量的最重要因素,主要通过剪切力评价,主要受肌内脂肪含量和肌纤维状态的影响。风味也是影响消费者接受程度的因素,主要与肉中挥发性化合物的种类和含量有关。文章综述了影响绵羊肉嫩度和肉风味的营养因素(饲料种类、饲喂方式、饲料添加剂)与遗传因素(品种、年龄、基因),以期为生产优质羊肉绵羊的饲养管理及遗传育种提供参考。     

日粮因素调控猪肌内脂肪沉积的研究进展（一）

肌内脂肪含量是影响猪肉品质的重要决定因素之一。研究证实，肌内脂肪的沉积受到遗传、日粮与环境等众多因素的影响，其中日粮因素又往往可通过环境和遗传等因素对肌内脂肪的沉积产生调控作用。为此，本文主要就日粮因素调控猪肌内脂肪的研究进展作一简要综述，以期为相关研究与肉猪生产提供科学参考，进而推动养猪业的健康发展。     

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.     

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.     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -