反刍家畜对易消化碳水化合物的需要

几十年来,国内外许多家畜营养工作者一直在研究反刍家畜对易消化碳水化合物的需要。本文现就这方面研究的资料作一介绍,供参考。     

反刍家畜水的营养与需要量

水在反刍家畜机体代谢中具有极其重要的作用,对于家畜的健康有着重要的意义。缺水可使反刍家畜的食欲降低、健康受损,生长家畜生长发育受阻,成年家畜生产力下降。轻度缺水往往不易被发现,但常在不知不觉中造成很大的经济损失。反刍家畜的需水量受许多因素和条件的控制,它随家畜是处于维持或生长、肥育、怀孕、泌乳等状态而各不相同。本文针对水在反刍家畜饲料和体内的含量、分布、影响需水量的因素、需水量及营养等各个不同的方面作了系统的阐述。     

生长激素对反刍畜营养需要量的影响

在反刍畜上应用剖分剂的目的是为了增加产乳量和生长率。效益的关键问题集中在ST对维持成本和营养需要量的影响上。本文旨在综述ST与反刍畜生长、日粮蛋白质需要量及日粮能量浓度的关系。 许多研究报告了bST和aST对牛和绵羊生长及胴体成份的影响。综合这些研究表明氮保留增加、胴体脂肪减少和瘦肉/脂肪的比率升高。而且ST增强氮利用的能力是由     

反刍家畜镁营养及缺镁症预防措施

反刍家畜易于缺镁。缺镁时,轻者采食减少,泌尿,心血管系统机能障碍,生产性能下降;重者痉挛甚至猝死。因此,反刍家畜的镁营养尤为重要。本文就镁在反刍家畜体内的生理作用、代谢及其影响因素、缺镁表现与缺镁症预防措施等作一综述。 一、镁对反刍家畜的生理作用 镁在反刍家畜体内的含量很少,约0.04％。其中,约70％的镁以磷酸盐和碳酸盐的形式存在于骨骼和牙齿中,成为其组分之一。30％镁含存于体液和软组织中。对于幼龄反刍家畜,当日粮镁不能满足其需要时,     

影响羊毛生长的遗传和环境因素

一、影响羊毛生长的环境因素 (一)营养因素 营养对羊毛生长的影响主要表现为营养对毛囊的可用性,它主要受到皮肤组织的血流和血液中营养物质浓度的影响。组织中营养物质的代谢率可以用Michealis一Menten动力学方程来描述,每个反应的速度都依赖于它的最大速度、底物与催化反应的酶之间     

1983年反刍家畜的营养研究(一)

瘤胃特性及其代谢 Baldwin等指出,过去25年对反刍家畜消化功能的认识有了很大提高,家畜生产之所以得到改进是由于应用了定量分析的方法。以今天应用定量分析所取得的成就将会产生甚至更大的效益。已经鉴定出了瘤胃的主要微生物,并对其营养需要量、生化途径和功能进行了大量描述。 对于瘤胃微生物之间复杂的相互作用的了解和对反刍家畜饲料化学成分、瘤胃消化     

高产奶牛饲养中的氨基酸

反刍家畜的氮素营养与前胃中微生物的生命活动有密切的联系。瘤胃微生物具有较高的水解蛋白质活性,可使饲料中的大部分蛋白质分解为肽和氨基酸,这两种物质可脱去氨基而形成氨。有很高生物学价值的菌体蛋白质的合成与分解过程是同时进行的。 不久前,人们认为反刍家畜通过瘤胃中微生物的合成作用能供给其本身所需的全部氨基酸,因此,形成了反刍家畜日粮中的氨基酸成分不必保持平衡的观点。但后来证     

反刍家畜代谢的激素调节(上)

能量代谢的主要变化发生在禁食期。由于从肠中的吸收量减少,营养物质的代谢在外周贮存进行(主要是防脂组织和肌肉)。这个变化受激素,主要是胰岛素的控制。在反刍和非反刍家畜中因胰岛素不足而产生的临床综合症状都相当严重,但存在差别。 调节规律中其它激素的作用还不清楚。胰高血糖素缺乏(Brockman,1979b)及肾上腺髓质和肾上腺皮质激素不足(Reilly和Black,1973)与休闲家畜的代谢失调无     

五年攻克癌症的第五号公告——全营养食疗对放弃医学治疗的临终最晚期癌症患者研究公告

[导言] 本研究是我们在2008年1月15日向社会公布的<五年攻克癌症宣言>后的第一期试验研究.在宣言中宣称,我们在已经进行的干细胞克隆器官和再生医学的研究中,发现癌细胞和正常细胞在生命营养物质的需求上有着本质的不同,细胞和动物试验的结果也显示,能促使正常细胞增殖分化的营养物质组合反而能导致癌细胞的终止生长;发现了这些现象后,我们则想到了人类癌症发病的主要原因是否有可能与人类摄取的营养物质不全有关,所以决定采取全营养食疗的方法进行人类攻克癌症的研究.     

小肠大量切除保留回盲瓣的意义

目的探讨大量小肠切除后,保留回肠末端回盲瓣的意义。方法回顾分析我院1995年以来13例大量小肠切除后,仅能保留10 cm以内回肠末端的患者的临床资料。结果全组均未出现明显短肠综合征表现。结论对于肠绞窄、外伤、肿瘤等原因导致切除大量病变肠管后,保留回盲瓣对于预防短肠综合征有重要临床意义,保留回盲瓣对于营养物质在小肠内的吸收、防止结肠内细菌向小肠迁移寄生有其生理意义。     

小RNA对细菌生物膜形成的调控研究进展

小RNA 在细菌的生长过程中发挥重要调控作用,在感受到外界信号,如营养物浓度、温度、pH值和渗透压的改变时,小RNA可通过影响靶标基因的表达以适应环境的变化.细菌由浮游状态向固体附着生长状态的转变过程中自身会产生一种细胞外基质,即生物膜,其主要由蛋白质、多糖和DNA组成.最新研究表明,小RNA在调控细菌生物膜形成的系统中发挥着重要的作用.小RNA通过与靶标mRNA碱基配对或与调节蛋白相互作用,在细菌生物膜形成中发挥调控作用.该文综述了小RNA对细菌生物膜形成的调控机制和途径,阐述了3种经典的小RNA调控细菌生物膜形成的模型,以及小RNA调控对细菌生物膜形成的研究现状和发展方向.     

Nutrient canal of the fibula

Objective. To investigate the radiological features of the nutrient canal in the fibula. Design and patients. One hundred and seventy-nine dried fibulae were studied regarding the type, number, location, and direction of the nutrient canal. They were classified into a usual type (type I: a radiolucent line confined to the cortex) and an atypical type (type II: a radiolucent line extending beyond the cortex). Results. Among the total of 230 nutrient canals seen on radiography, 197 (86%) were type I and 33 (14%) were type II. On CT scans, the ossified rim of the canal extended into the medullary cavity in type II canals. The most common site was the posteromedial aspect in both type I and type II canals. Type II canals were significantly more common in fibulae with two or three nutrient canals. The frequency of the upward direction was more common in type II canals. Conclusion. Nutrient canals with extension of the ossified rim into the medullary canal are the cause of linear lucency that may simulate a fracture. Their features are slightly different from those of usual canals. Received: 13 July 1999 Revision requested: 20 September 1999 Revision received: 13 October 1999 Accepted: 18 October 1999     

Exercise-induced alterations in muscle lipid metabolism improve insulin sensitivity

Exercise is a key component for the successful management of many obesity-related metabolic complications, including insulin resistance. This review addresses the effect of chronic and acute endurance exercise on insulin action in obesity and the role of exercise-induced alterations in fatty acid partitioning within the muscle cell on insulin sensitivity.     

Nutrient groove of the ilium,a subtle but important forensic radiographic marker in the identification of victims of severe trauma

A variety of skeletal characteristics pertaining to the bony pelvis have, over the years, been of assistance as forensic markers, but the importance of the nutrient groove of the ilium has not been appreciated. During aircraft accident investigations we compared premortem anteroposterior abdominal radiographs with postmortem specimen radiographs of the ilium, with particular attention directed to the nutrient groove of the ilium. This marker can assume several configurations (i.e., parallel, V-shaped and Y-shaped) and is situated a few centimeters lateral to the sacroiliac joint. Left/right asymmetry, or absence of the nutrient grove on one side of the pelvis are possible variants within an individual. The purpose of this report is to emphasize the previously unrecognized importance of the nutrient groove of the ilium as a useful forensic radiographic marker.The opinions or assertions contained herein are the private views of the authors and are not be construed as official or as reflecting the views of the Department of the Army, Department of the Navy or the Department of Defense.     

Heredity and the path to overweight and obesity

Overweight and obesity are not homogeneous phenotypes as individuals differ in terms of the regional distribution of the excess weight or fat. Overweight and obesity are also complex multifactorial phenotypes influenced by both genetic and nongenetic determinants. Heritability of fat mass or percent body fat derived from underwater weighing measurement reaches about 25% of the age and gender adjusted phenotypic variance. Based on twin and parent-child data, it has been reported that the heritability of resting metabolic rate, thermic response to food, and energy cost of submaximal exercise, adjusted for the proper concomitants, is as high as 40%. The level of habitual physical activity also exhibits a significant heritability level on the order of about 25%. Experimental overfeeding with identical twins demonstrates that there are inherited differences in body weight and body composition response. The most important factor identified thus far to account for the individual differences in response to long-term overfeeding is a nutrient partitioning characteristic, namely the proportion of fat vs lean tissue gained. The high gainers are those storing energy primarily in the form of fat, while the low gainers are storing relatively more in the form of lean tissue.     

绵羊妊娠期和哺乳期能量蛋白质营养需要的研究进展

本文综述了绵羊的能量白质代谢体系的研究方法及绵羊在妊娠期和哺乳期能量和蛋白质营养需要的研究进展。     

Comparison of intracellular pH measurements by 31P NMR and weak acid partitioning in Chinese hamster ovary fibroblasts

Intracellular pH measurements obtained by 31P NMR and DMO partitioning are compared. A continuous-flow culture system was used to measure the intracellular pH of Chinese hamster ovary fibroblasts in response to changes in the extracellular pH. These measurements were repeated with the CHO cells in suspension and under similar experimental conditions using the weak acid partitioning technique employing 14C-DMO. It is shown that the pHi values are identical, within experimental error, for both techniques in the 6.80-7.70 pH range, with the DMO technique giving slightly more acidic intracellular pH in the 6.00-6.80 range. It is concluded that both techniques give similar values for intracellular pH in the physiological range, with the DMO partitioning giving more acidic values at pH's less than 6.80. The range of validity for pHi measurements using 31P NMR lies between 6.70 and 7.50.     

Fluid replacement during sustained activity in the heat: nutrient solution vs. water

This study examined the thermoregulatory and hydrational status of men during sustained activity in a hot-dry (37 degrees C, 20% rh) environment while they consumed only a nutrient solution (nutrient), or consumed only colored, flavored water (control). Eleven heat acclimated young men attempted 24-h sustained activity experiments. These experiments consisted of alternating 45-min bouts of treadmill walking (410 W, approximately 30% VO2max) and rest (including sedentary activity). Data were analyzed through 13 h (after 13 h subjects began to discontinue testing). No significant differences between trials were observed for metabolic rate, fluid intake, skin or rectal temperature, sweating rate, plasma volume (as indicated by hemoglobin concentration) or plasma glucose concentrations. By the 8th h plasma osmolality was higher and by the 11th h plasma free fatty acids were lower during the nutrient trial compared to the control. In separate experiments with nine different men, the gastric emptying rates of the nutrient solution and water were compared during exercise (55% VO2max) in the heat (35 degrees C, 20% rh). The gastric emptying rates of the nutrient solution and water were similar (approximately 20 ml.min-1). These data indicate that during 13 h of sustained activity in a hot environment, the nutrient solution and water provided similar thermoregulatory and hydrational benefits.     

Multi-spectral image analysis and classification of melanoma using fuzzy membership based partitions.

The sensitivity and specificity of melanoma diagnosis can be improved by adding the lesion depth and structure information obtained from the multi-spectral, trans-illumination images to the surface characteristic information obtained from the epi-illumination images. Wavelet transform based bi-modal channel energy features obtained from the images are used in the analysis. Methods using both crisp and fuzzy membership based partitioning of the feature space are evaluated. For this purpose, the ADWAT classification method that uses crisp partitioning is extended to handle multi-spectral image data. Also, multi-dimensional fuzzy membership functions with Gaussian and Bell profiles are proposed for classification. Results show that the fuzzy membership functions with Bell profile are more effective than the extended ADWAT method in discriminating melanoma from dysplastic nevus.     

An analysis of directional changes in the center of pressure trajectory during stance

This study proposes a new approach of posturography analysis, which enables the evaluation of directional changes in the center of pressure trajectory. The concept is similar to that of so-called “stabilogram diffusion analysis”. Instead of calculating the distance traveled by the center of pressure in a certain time interval, this new method calculates the cosine of the instantaneous velocity vectors of the center of pressure, which corresponds to the amount of change in the sway direction (cosine = 1 corresponds to the identical direction; cosine = ?1 corresponds to the opposite direction). This method was applied to the analysis of the experimental data in which postural sway was collected under four conditions: open eyes, closed eyes, and two auditory biofeedback conditions. In the biofeedback conditions, auditory signal was given to the subjects when the center of pressure swayed out of a certain area. As results, the differences in the postural reaction under these conditions were clearly shown using the new method. The results indicated that the subjects reacted to the auditory signals by swaying in the opposite direction with biofeedback. It was also found that the eyes open condition exhibited a more random-like profile. As this method analyzes the directional change in the postural sway, this method can be utilized cooperatively together with such a method as stabilogram diffusion analysis, which analyzes the magnitude of sway.