Effects of tannin on selection by sheep of forages containing alkaloids,tannins and saponins

BACKGROUND: Mixtures of plant species provide biochemical diversity to pastures which may enhance productivity while decreasing reliance on herbicides and insecticides. All plants contain secondary metabolites (PSMs) that interact in plant communities in a variety of ways. For instance, tannins are a group of highly reactive chemical compounds with the potential to interact with other PSM such as alkaloids and saponins, neutralizing their negative effects. Our objective was to determine whether tannins modify the foraging behavior of sheep grazing on varieties of alfalfa, birdsfoot trefoil and tall fescue with high and low concentrations of saponins, tannins and alkaloids, respectively. RESULTS: Lambs that received intraruminal infusions of tannins increased their consumption of the high‐saponin variety of alfalfa and the high‐alkaloid variety of tall fescue relative to lambs not infused with tannins (controls). Lambs infused with tannins and then offered choices among the three high‐PSM varieties of the forages also manifested higher consumption of the high‐alkaloid variety of tall fescue than control lambs. In contrast, lambs infused with tannins reduced their consumption of the high‐tannin variety of birdsfoot trefoil. Thus lambs modified their foraging behavior as a function of the presence/absence of tannins in their rumens. CONCLUSIONS: These results indicate that ruminants are able to discriminate the specific post‐ingestive effects of forage varieties with high concentrations of PSM, and that PSM complementarities are likely to increase the efficiency of use of diverse forages with different biochemistries. Copyright © 2009 Society of Chemical Industry     

羊血中超氧化物歧化酶提取工艺研究——热变温度、热变时间和热变方式对SOD提取的影响及最佳工艺条件选择

目的:重点研究热变温度、热变时间、热变方式对SOD分离提取的影响,确定最优工艺参数。方法:采用正交试验设计。由正交试验得出最优组合为A2B2C2,即热变温度55℃,热变时间15min,0.01mol/lCuCl2的添加量2%。结论:热变性是羊血SOD提取的关键,按此工艺热变性后的SOD活性在1000U/mg蛋白以上。     

响应面分析法优化羊血中SOD的热变性提纯工艺条件

利用响应面分析法(Response Surface Methodology)对羊血中SOD的热变性提纯工艺进行优化。在单因素实验基础上选取实验因素与水平,根据中心组合(Box-Benhnken)实验设计原理采用3因素水平的响应面分析法,依据回归分析确定各工艺条件的影响因子,以SOD的比活力为响应值作响应面和等高线。在分析各个因素的显著性和交互作用后,得出最佳工艺条件为:热变性温度55℃;热变性时间15min;0.01mol/lCuCl2的添加量2%。在最佳工艺条件下,SOD活性为1072.43U/mg蛋白。     

血水比例对羊血豆腐凝胶特性和品质的影响

血水比例是调控血豆腐口感品质的关键。本实验以湖羊血液为原料,按照血水比(v/v)1∶0、1∶1、1∶2、1∶3、1∶4、1∶5、1∶6稀释后制作血豆腐凝胶,从血浆纤维蛋白原浓度、动态流变特性、微观结构、质构、保水性等指标的角度,研究血水比例对血豆腐凝胶特性和品质的影响。结果表明:随着血浓度降低,血豆腐储能模量、损能模量弱化,凝胶强度呈下降趋势,同时血豆腐凝胶蒸煮损失和离心损失增大,不易流动水比例下降,水分向慢弛豫方向移动。当血水比<1∶3时,凝胶网状结构稳定性下降,水分易渗出,且不具有动态流变特性,凝胶强度极弱;除弹性外,血豆腐硬度、咀嚼性、内聚性以及黏性均显著降低。血水比≥1∶3时能较好地保持羊血豆腐凝胶的质构特性和持水力,是制作血豆腐的适宜比例范围。      

蒸煮时间对滩羊肉蒸煮损失、嫩度及水分分布的影响

为了探究蒸煮时间对滩羊肉蒸煮损失、嫩度及水分分布的影响。对不同蒸煮时间处理下的滩羊肉蒸煮损失、剪切力进行测定,并结合低场核磁技术研究滩羊肉水分子T_2弛豫特性以及各指标间的相关性。结果表明:随着蒸煮时间的延长,滩羊肉的蒸煮损失和剪切力先增大后减小(P0.05)。LF-NMR检测到了4个明显的水分群,代表肉中的弱结合水(T_(21))、强结合水(T_(22))、不易流动水(T_(23))和自由水(T_(24))4种存在状态。延长蒸煮时间,弛豫时间先变长后缩短,T_(23)含量先减少后增加,T24含量先增加后减少。核磁成像结果显示,蒸煮时间的延长会使图像的亮度先增强后减弱。相关性分析结果表明,蒸煮损失与T_(23)、T_(24)呈显著正相关(P0.05),相关系数分别为0.966,0.994;剪切力与T_(23)呈显著正相关(P0.05),相关系数为0.846,与T23峰面积比例呈显著负相关(P0.05),相关系数为-0.504。说明不同蒸煮时间处理下的滩羊肉的蒸煮损失、嫩度及水分分布均具有显著的变化,且各指标之间具有显著的相关性。     

Comparison between two different methods for evaluating rumen papillae measures related to different diets

Although the Geographical Information System (GIS), which integrates computerized drawing computer assisted design (CAD) and relational databases (data base management system (DBMS)), is best known for applications in geographical and planning cartography, it can also use many kinds of information concerning the territory. A multidisciplinary project was initiated since 5 years a multidisciplinary study was initiated to use GIS to integrate environmental and ecological data with findings on animal health, ethology, and anatomy. This study is chiefly aimed at comparing two different methods for measuring the absorptive surface of rumen papillae. To this scope, 21 female sheep (Ovis aries) on different alimentary regimes (e.g., milk and forage mixed diet, early herbaceous diet, dry hay diet, and fresh hay diet at the maximum of pasture flowering and at the maximum of pasture dryness) were used; after slaughtering, 20 papillae were randomly removed from each sample collected from four indicator regions of rumen wall, placed near a metric reference and digitally photographed. The images were developed with the ArcGIS? software to calculate the area of rumen papillae by means of GIS and to measure their mid‐level width and length to calculate the papillae area as previously performed with a different method. Spatial measurements were analyzed using univariate and multivariate methods. This work demonstrates that the GIS methodology can be efficiently used for measuring the absorptive surface of rumen papillae. In addition, GIS demonstrated to be a rapid, precise, and objective tool when compared with previously used method. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

简析内蒙古烤羊腿制作工艺

烤羊腿制作工序复杂 ,须经选料、初加工、腌渍入味、保护及优化、烤制成熟等工序 ,各道工序操作严格 ,成品味感美 ,色红亮 ,地方风味足 ,符合卫生标准     

Feeding Behavior of Lambs in Relation to Kinetics of 1,8-cineole Dosed Intravenously or into the Rumen

The monoterpene 1,8-cineole is a major constituent of the essential oils that adversely influence intake of sagebrush by herbivores, but little is known about the mechanisms of its action. We investigated the influence of 1,8-cineole on the feeding behavior of two groups of sheep, one group dosed intravenously and the other intraruminally. In the first study, we infused 40 mg/kg BW of 1,8-cineole intravenously into four lambs on wk 1, 2, and 4. In the second, we administered 125 mg/kg BW of 1,8-cineole into the rumen of four lambs as a single-bolus dose in wk 1 and 2. Lambs dosed intravenously spent less time feeding than controls (28 vs. 60 min; P < 0.05), as did lambs dosed intraruminally (35 vs. 60 min; P < 0.05). Dosed lambs ate less than controls during rumen dosing studies (P < 0.05). For the intravenous infusion studies, rates of elimination did not differ among weeks (P < 0.05). For the rumen infusion studies, however, the absorption rate constant increased from 0.035/min to 0.076/min from wk 1 to 2, while the absorption half-life declined from 24 to 10 min (P < 0.05). Maximum plasma concentrations and time to reach maximum plasma concentrations were no faster in wk 2 than wk 1, but the primary elimination rate constant was 2.3 times higher in wk 2 (0.058/min) than in wk 1 (0.025/min) (P < 0.05). Dosed lambs exhibited clinical effects—licking of lips, drowsiness, staggering, and 1,8-cineole-smelling breath—that were much more pronounced with intravenous than rumen infusions. Dosing did not affect the acid–base balance. Collectively, these data suggest 1) rapid absorption and distribution of 1,8-cineole was responsible for initiating satiety, while more prolonged excretion was responsible for the duration of the satiety effect, and 2) lambs more readily adapted to 1,8-cineole in the rumen-dose study than in the intravenous-dose study.     

Ruminal metabolism of leafy spurge in sheep and goats: A potential explanation for differential foraging on spurge by sheep,goats, and cattle

Leafy spurge (Euphorbia esula) is an introduced forb that is invading western rangelands. Goats (Capra hircus) readily graze the plant, but cattle (Bos tarus) generally and sheep (Ovis aries) locally appear to develop conditioned flavor aversions to leafy spurge. They either avoid the plant entirely or graze it reluctantly. We hypothesized that: (1) a diterpene diester that can occur in leafy spurge was an aversive agent, and (2) diet selection differences among ruminant species may be partly a function of differential ruminai metabolism of aversive phytochemicals, and further that cattle and sheep may be reluctant to graze leafy spurge because their ruminai microbes do not metabolize certain leafy spurge chemicals as do ruminai microbes in goats. Sheep did not develop an aversion to a novel food when its consumption was followed by an intravenous injection of ingenol 3,20-dibenzoate (P=0.34). Sheep did develop an aversion to a novel food when its intake was followed by a dose of leafy spurge fermented with sheep ruminai digesta, but not when followed by a dose of leafy spurge fermented with goat ruminai digesta (P= 0.03). This suggests that goat ruminai microbes may modify leafy spurge such that it does not elicit an aversion in sheep.This research was supported in part by a grant from the Cooperative States Research Service (91-38300-6158). All experimental procedures with ruminants followed a protocol approved by the U.S. Sheep Experiment Station's Animal Care and Use Committee. Mention of trade names or companies does not constitute an implied warranty by USDA or the authors.     

核事故释出~(131)I对羊的污染研究

本文采用放射化学分析法,研究了苏联切尔诺贝利核电站事故释出的~(151)I对新疆地区羊胃内容物、血、肌肉和甲状腺的污染规律。结果表明:事故后24天羊甲状腺~(151)I达到最大污染水平,其后按指数规律下降。~(151)I在羊甲状腺、血、肌肉和胃内容物中的有效半排期分别为:7.2、6.7、6.7和5.1天。羊胃内容物、血、肌肉和甲状腺中~(151)I的比活度之间呈直线正相关。 在~(151)I污染期间,用库存饲料圈养的羊的甲状腺中~(151)I比活度仅为野外放牧羊的1.7±0.7％。由羊甲状腺污染水平估算出此次事故~(151)I对新疆地区和乌鲁木齐成年人的待积有效剂量当量分别为3.8μSv和14.0μSv,不会对居民健康产生明显不良影响。