反刍动物对纤维素的消化机制

反刍动物之所以能消化利用粗饲料中的纤维素等多糖类物质，是因为它们具有瘤胃这一独特的消化发酵罐，其内存在着大量的厌氧微生物．主要包括细菌、真菌和原生动物。其中．瘤胃细菌和瘤胃真菌能分泌纤维素酶，对纤维素有较强的降解能力。     

日粮因素对反刍动物瘤胃消化代谢影响的研究现状

本文对反刍动物的瘤胃发酵作了总结,其中重点阐述了通过日粮组成对瘤胃消化代谢产物的影响,以便最大限度地发挥瘤胃发酵的有益方面,提高饲料的利用效率和生产性能。     

日粮因素对反刍动物瘤胃消化代谢影响的研究现状

本文对反刍动物的瘤胃发酵作了总结,其中重点阐述了通过日粮组成对瘤胃消化代谢产物的影响,以便最大限度地发挥瘤胃发酵的有益方面,提高饲料的利用效率争生产性能。     

反刍动物对纤维素的消化机制

反刍动物之所以能消化利用粗饲料中的纤维素等多糖类物质,是因为它们具有瘤胃这一独特的消化发酵罐,其内存在着大量的厌氧微生物,主要包括细菌、真菌和原生动物。其中,瘤胃细菌和瘤胃真菌能分泌纤维素酶,对纤维素有较强的降解能力。     

日粮能量浓度对反刍动物瘤胃消化生理影响的研究

取3只装有永久性瘤胃瘘管的小尾寒羊（体重28.3±3.8kg）进行瘤胃消化代谢试验，按3×3拉丁方试验设计，喂给三种日粮，代谢能浓度（MJ·KgDM-1）分别为：高浓度组（HC）11.32、低浓度组（LC）10.44和中浓度组（CM）11.O1；粗蛋白含量13.75％。试验结果表明，瘤胃稀释速率7.81％·h~(-1)，瘤胃体积2.421，平均流速187.2ml·h-1，周转率12.87h·次-1；冻干菌含量2.24mg·ml-1，细菌含蛋白质量60％，瘤胃液菌蛋白含量1.35mg·ml-1，原虫蛋白含量0.17mg·ml-1，RNA-N5.78mg·g-1，DNA-N1.84mg·g-1，RNA-N／BN6.11％，DNA-N/BN1.98％，核酸N／BN8.09%，瘤胃液pH值平均6.13，TVFA4.96mmol·100ml-1，乙酸：丙酸：丁酸46.6：34.7：18.7，乙酸／丙酸1.35，（乙酸 丁酸）／丙酸1.90。     

反刍动物瘤胃微生物对粗饲料的利用

国际饲料分类法与我国饲料分类方法均将饲料中自然含水量低于45％,粗纤维高于18％的饲料划为粗饲料,包括青绿饲料制得的干草(粉)、脱谷收得农副产品(秸杆、秕壳等)以及糟渣类、饼粕产物、草籽、油料籽实等饲料。这类饲料一般营养价值相对低,其主要利用者为反刍动物,利用的关键在于瘤胃微生物对粗饲料的摄取、消化、降解的能力。研究反刍动物瘤胃微生物对粗饲料的摄取、消化、降解的机理以提高反刍动物粗饲料的利用效率一直是饲料科学和相关领域十分关注的课题。     

影响反刍动物肠内淀粉消化的因素

淀粉在反刍动物中的吸收过程比较复杂,反刍动物通常消化淀粉食入量的75％～80％。没有发酵就进入到小肠的淀粉更不容易被酶消化,进入到小肠的淀粉平均只有35％～60％被分解,而没有在小肠中消化的那部分在大肠中又有35％～50％被分解,这就表明小肠消化的局限性确实存在。本文就影响小肠淀粉消化和吸收的营养因素作一综述。     

反刍动物瘤胃真菌的功能、影响因素及应用

瘤胃是反刍动物最主要的消化器官,寄养着细菌、真菌、原虫、古生菌等多种微生物,这些瘤胃微生物菌群在反刍动物消化系统中起着重要作用。瘤胃真菌在瘤胃微生物中占比较小,且绝大多数为厌氧真菌。瘤胃真菌可以充分降解纤维物质,同时真菌还参与蛋白质和淀粉的降解过程,以提高饲料的利用率。瘤胃真菌的数量容易受硫元素、氮元素以及瘤胃内其他微生物的影响,因而从这些方面对饲粮进行调控,能够提高瘤胃内真菌的数量,从而提高反刍动物的消化能力和对饲料的利用。文章结合国内外研究进展,从瘤胃真菌特点、功能、影响因素及应用等多个方面进行综述,以期为反刍动物的健康养殖提供参考。     

鹅消化利用纤维的生理特点及影响因素

鹅属草食性水禽,其对纤维的消化利用过程与鸡、鸭等有较大区别。长期以来,鹅日粮纤维的使用缺乏统一的饲料营养标准,养殖从业人员对鹅消化利用纤维的生理特点认识不全面。文章旨在详细介绍鹅消化利用纤维的主要生理特点,并从纤维来源、营养水平、鹅品种、日龄等方面综述其对鹅纤维消化利用的影响,为生产中纤维饲料原料的合理使用提供技术支持。     

外源纤维复合酶在反刍动物应用中的研究进展

纤维复合酶具有破坏植物细胞壁,补充动物内源酶不足,提高反刍动物对粗饲料利用率等作用,近年来将其应用于反刍动物饲料中。通常用来提高非反刍动物饲料的营养价值(特别是对肉鸡日粮),或作为青贮添加剂;而在反刍动物饲养上的应用研究起步较晚。一般不添加于成年反刍动物日粮中,因为瘤胃内的纤维分解活动很活跃,所以简单地添加外源酶制剂不会提高纤维分解活动;还认为,外源纤维复合酶在瘤胃中被蛋白酶所水解或受小肠蛋白酶的作用而失活。研究结果多不一致,有的有效,有的无效;甚至有的不但无效,反而有副作用。但是,最近研究发现纤维素酶、半纤维…     

Determination of in vitro digestibility of forage species used in ruminant feeding

Within the evaluation of the quality of forage resources, the main parameter that defines it is the digestibility of dry matter, which together with the amount of neutral and acidic detergent fibers and crude protein constitutes the basic information to assess forages which are supplied in the diet of the cattle. This research was carried out at the University of Los Llanos (Villavicencio, Colombia), and its objective was to determine the digestibility of three forages in cattle through three different in vitro techniques: inoculation with ruminal fluid and with feces and enzymatic digestibility technique, making the comparison with the in situ technique in order to validate the techniques and equipment that are being used for these procedures. The following species were evaluated: Pennisetum purpureum (PP), Tithonia diversifolia (TD), and Bauhinia variegata (BV), assessing the curve and rate of degradation of dry matter (DM), neutral detergent fiber (NDF), and total protein (TP) (0 to 72 h). A design of repeated measures was used, under which the analysis of variance was carried out to determine the ranges of deviation between the techniques and thus establish the trend of the data; the variables evaluated were the DM, NDF, and TP digestibilities of the three forages using the four techniques (three in vitro and one in situ). After verifying the differences between the variances of the digestibilities and checking the sphericity assumption with the Mauchly test, multiple comparisons were made with the Bonferroni test with a significance of 5%. The digestibility of DM, NDF, and TP varied between 38.62 and 44.22, 54.18 and 66.97, and 47.54 and 57.05%; 49.07 and 70.70, 72.52 and 75.44, and 62.61 and 74.02%; 29.93 and 34.84, 26.21 and 70.88, and 25.67 and 50.60% respectively in forages PP, TD, and BV, depending on the technique used for their estimation. Despite finding statistically significant differences between several of the comparisons made in the digestibility techniques, a high coefficient of determination and a high correlation between the in vitro estimations with respect to the in situ estimation were found; therefore, it is possible to use these techniques routinely thus avoiding the need to have cattle with fistulae to perform digestibility tests, with enzymatic digestibility technique being the most practical one.

     

影响反刍家畜超数排卵的因素浅析

目前．研究者在胚胎移植的研究和应用方面取得了很大的进展．胚胎移植的基本程序已经建立起来。但是，作为胚胎移植技术的重要前期工作——超数排卵技术．仍然有许多问题需要解决，尤其是供体对超排反应的不稳定性及超排后许多供体不能产生可用于移植的胚胎．这些都大大限制了胚胎移植技术的常规应用。本文就影响超数排卵反应稳定性的因素做了较全面的分析和讨论。     

纤维素分解菌在反刍动物营养代谢中的研究进展

目前．我国北方地区仍以玉米秸秆等劣质粗饲料作为反刍动物的部分能量来源。但由于这类饲料质地粗硬、适口性差,导致反刍动物采食量降低．从而影响营养物质的吸收．造成生产效率低下．因此很多研究人员对如何提高劣质粗饲料的消化率进行了大量的研究。研究反刍动物对粗饲料的利用．实际上就是研究瘤胃内微生物如何利用粗纤维的过程。本文主要从瘤胃内纤维素分解菌的特性．影响其降解能力的因素及国内外研究进展几个方面进行阐述。     

Influence of cellulose fibre length on faecal quality,mineral excretion and nutrient digestibility in cat

In dogs, faeces quality and nutrients digestibility were affected by different types of cellulose ( Wichert et al., 2002 ). In this study, it was investigated whether there are comparable effects of cellulose type in cats. Seven adult, healthy cats were fed a moist commercial complete cat food with three different cellulose type added at a level of 4% for a 1 week period. Faeces quality was between 1 and 3 on the scale used from 1 to 5. The addition of long fibre cellulose resulted in significantly firmer faeces. Addition of cellulose decreased the digestibility of dry matter and energy, whereas the impact on protein and fat digestibility was not significant. The type of cellulose affected faecal bulk and faecal water excretion. Faecal excretion of sodium and potassium was exponentially correlated to faecal water, faecal bulk and to a lesser extent to faecal dry matter excretion. Faecal calcium, magnesium and phosphorus excretion showed an exponential correlation to faecal dry matter excretion. A weaker correlation existed in all three elements to faecal bulk, whereas the effect of faecal water excretion was small. Results suggest a remarkable likeness between cats and dogs with regard to the digestive physiology of major minerals.     

反刍动物常用粗饲料消化率预测模型的验证研究

研究通过对江西反刍动物常用粗饲料体外消化率(IVDMD)的实际测定,证明邓卫东等(2002)建立的以范氏纤维含量为预测因子的粗饲料IVDMD预测模型在江西区域有较高的准确性,能够应用于江西反刍动物粗饲料消化率的预测。该模型与张吉鹍等(2004b;2010)建立的粗饲料干物质采食量预测模型构成了完整的反刍动物粗饲料分级指数(GI)参数模型,这将大力推进江西反刍动物粗饲料品质的综合评定。     

Control mechanisms for producing antimicrobial factors in ruminant mammary gland

Mastitis, a symptom of inflammation in mammary tissue by infection with various kinds of bacteria, causes huge economic losses in the milk industry. One of the popular methods for treatment of mastitis is antibiotics, although this prohibits milk shipping and sometimes causes resistant microbes. Therefore, a new strategy to treat mastitis without antibiotics is eagerly required around the world. Antimicrobial factors belong to innate immunity and can start their function extremely early after bacterial stimulation. These factors have antimicrobial activity for a broad spectrum of bacteria. Elucidation of causal mechanisms and functions of antimicrobial factors in the mammary gland is thought to result in suitable methods for prevention and treatment of mastitis. Therefore, this review introduces traits of some antimicrobial factors and the mechanisms for expressing, producing and secreting them in the mammary gland. For antimicrobial factors, lingual antimicrobial peptide (LAP), S100A7, cathelicidin and lactoferrin are controlled in different sites and different time courses, suggesting that antimicrobial factors play different roles for local defense against bacterial infection in the mammary gland. These findings will contribute to the development of prevention and treatment methods for mastitis.     

日粮营养素对反刍动物免疫能力的影响

近年来，由于禁用或限用某些抗生素药物添加剂，人们的饲料安全意识提高，倍加关注动物营养与免疫关系的研究。 影响反刍动物免疫能力的营养素包括：蛋白质、能量、维生素和矿物质。每种营养素都可能影响特异免疫或非特异免疫。了解这些营养素间的互作很重要。任何一种营养素缺乏或过量都能影响其他营养素的作用。本文仅讨论日粮能量与蛋白质、维生素Ｅ与硒、锌、铜和铬对反刍动物免疫能力的影响。１特异免疫与非特异免疫 动物通过调节特异免疫和非特异免疫的反应强度来维持机体正常的防御机能。特异免疫主要有两种：１）体液免疫：血液循环…     

反刍动物共轭亚油酸的合成及其影响因素

共轭亚油酸(Conjugatedlinoleicacid ,CLA)指一系列含有共轭双键、具有位置和空间构型不同的十八碳二烯酸同分异构体的混合物,是一种天然活性物质。共轭亚油酸具有很强的生理功能,主要有抗癌、抗动脉粥样硬化、抗氧化、降低胆固醇、促进生长、抑制脂肪累积、增强机体免疫能力、改善骨组织代谢和抗糖尿病等功能。CLA能改善动物机体代谢,重新分配营养素,减少脂肪沉积,增加瘦肉率和提高免疫系统功能等。共轭亚油酸成为目前动物营养等研究领域的热点,主要集中在共轭亚油酸的生理作用、来源和对提高畜禽肉品质的影响,而对于CLA在反刍动物体内…