日粮纤维对反刍动物瘤胃发酵的影响

日粮纤维的化学和物理特性对于刺激其咀嚼活动和维持稳定的乳脂率十分重要,其中有效纤维的含量也是影响瘤胃发酵的重要指标。奶牛对日粮中有效中性洗涤纤维(eNDF)水平的反应是乳脂率的变化,而对日粮中物理有效中性洗涤纤维(peNDF)水平的反应是其咀嚼活动。     

日粮中添加活性干酵母对反刍动物的影响

活性干酵母是一种活的天然产生的酵母原料,作为瘤胃发酵的调控剂,不仅可以改善瘤胃内环境,而且没有类似抗生素的药物残留问题,已被广泛地应用于反刍动物生产中。本文就活性干酵母在反刍动物中的作用原理、效果做一个简述。     

日粮营养调控牛乳脂中共轭亚油酸CLA的含量

共轭亚油酸(conjugated linoleic acids CLA)是亚油酸的一组构象和位置异构体,是专一存在于反刍动物脂肪中的具抗癌活性的天然活性成分。日粮因素能影响并改变CLA的含量。本文主要阐述CLA的结构、生理作用以及影响牛乳脂肪中CLA含量的日粮因素。     

日粮脂肪对牛奶中CLA含量的影响

共轭亚油酸(Conjugated Linoleie Acid,CLA)是指含有共轭双键18碳脂肪酸的总称.近年的研究表明,共轭亚油酸对机体激素代谢和许多酶的活性起调控作用,具有降低心脏病和乳腺肿瘤发病率、抑制前列腺增生、延缓免疫功能衰退、提高新生儿脑和视力发育等特殊生物学功能及营养调节作用.奶产品是人们日常获取CLA的重要渠道.随着人们生活水平的提高和对牛奶营养认识的增加,牛奶的消费量越来越大,改善和提高牛奶中的CLA含量已成为当前的研究热点之一.影响奶牛乳中CLA合成的主要因素是日粮结构,本文对近年来日粮添加脂肪对牛奶中CLA含量影响的研究进展综述如下.     

日粮粗蛋白水平对反刍动物瘤胃发酵和微生物区系影响的研究进展

蛋白质是反刍动物的必需营养素,不同蛋白质水平日粮使瘤胃发酵参数发生改变。本文就不同蛋白水平日粮对瘤胃pH、NH3-N、VFA的浓度和瘤胃微生物区系组成的影响研究进展情况进行综述,为进一步开展相关研究奠定基础。     

反刍动物日粮中添加脂肪对瘤胃机能及生产性能的影响

脂肪为动物所必需的六大营养物质之一,在动物营养中具有特殊作用:①提供必需脂肪酸和胆碱;②作为脂溶性维生素的溶剂,促进 V_A、V_D、V_E、V_K 和胡萝卜素的吸收;③作为能量的主要给源。近年来,国外有关反刍动物日粮中添加脂肪对瘤胃机能和生产性能影响的研究,已有较多的文献报道。研究表明,反刍动物采食低脂日粮,可限制其生产性能的充分发挥;若直接向日粮中添加脂肪,则可抑制瘤胃微生物活动,降低纤维素消化率,但可提高产奶量;如果将脂肪进行包被,通过瘤胃在小肠进行消化吸收,不仅可显著提高产奶量和乳脂率,而且使瘤胃机能正常化,对纤维素消化率也没有     

日粮淀粉水平对内蒙古白绒山羊淀粉消化规律的影响

反刍动物由于瘤胃的发酵作用，饲料内的淀粉在瘤胃内大多数被降解成为挥发性脂肪酸，直接在消化道内被消化的淀粉数量非常少。研究表明，当日粮中淀粉浓度增加时，有较大比例的淀粉逃脱瘤胃微生物的作用进入小肠消化(Karr等，1966；Waldo，1973)。而淀粉在小肠中的消化程度受多种因素的影响，且动物个体和品种间存在差异。淀粉在反刍动物小肠内的消失率和消失量的研究结果，各国报道的数值差异较大。目前各国学者或研究淀粉在瘤胃中的降解或     

尿素-麻饼型日粮中添加烟酸对绵羊瘤胃发酵的影响

烟酸是畜禽必需的维生素之一，是动物体内2个重要脱氢酶的辅酶NAD^ 和NADP^ 的重要成分，在动物机体代谢中起着至关重要的作用。麻饼作为反刍动物常用的一种饲料原料，可以提供瘤胃蛋白来源,而尿素又是一种反刍动物最常用的非蛋白含氮物质．研究它们配合后的日粮对反刍动物及其瘤胃发酵的影响是非常有必要的。试验利用体外试验法，以内蒙古半细毛羯羊为试验动物，在以尿素一麻饼型日粮为培养底物的培养液中补加不同剂量的烟酸后,测定其若干瘤胃指标。用以确定烟酸适宜添加剂量范围，为配制舍饲育肥绵羊预混料提供理论依据。     

低蛋白饲粮对反刍动物生产性能、瘤胃发酵及氮排放的影响研究进展

随着蛋白质类饲料资源短缺、饲养成本增加以及饲料转化率较低的现状,我国畜牧业的发展受到严重阻碍,加之养殖业产生的废弃物造成大量的环境污染,在不影响畜禽生产性能的情况下采用低蛋白饲粮技术是目前解决此类问题的有效办法。本文简述了低蛋白饲粮的定义,重点总结了低蛋白饲粮对反刍动物生产性能、瘤胃发酵性能以及氮排放的影响,以期为今后畜牧科学研究及生产实践提供参考。[关键词] 低蛋白饲粮|反刍动物|生产性能|瘤胃发酵|氮排放     

影响反刍动物产品中共轭亚油酸富集因素的研究进展

共轭亚油酸(CLA)又被称为过瘤胃脂肪酸。近年来,随着CLA对人体健康的重要作用被陆续发现,通过饲养途径如何提高反刍动物产品中CLA含量成为当前动物营养研究领域的热点。本文在查阅国内外CLA最新研究进展的基础上,对影响反刍动物产品中CLA合成的因素加以综述。     

影响反刍动物产品中共轭亚油酸含量的饲粮因素探讨

共轭亚油酸(CLA)具有抗癌、抗动脉粥样硬化、抗氧化、降低脂肪沉积、促进生长以及调节免疫等重要的生理功能。人类食物中的CLA主要来源于反刍动物产品。影响反刍动物产品CLA含量的因素主要包括:(1)饲粮中的脂类底物;(2)瘤胃内环境的改变;(3)饲喂方式;(4)饲粮中CLA的供给。生产中可以通过饲粮来调控瘤胃微生物区系,以增加CLA的合成;也可以给饲粮提供富含亚油酸的原料,通过增加底物来提高反刍动物产品中的CLA含量。     

不同形式的氮源对活体外瘤胃氨氮释放和发酵参数的影响

选用普通尿素、两种包被缓释尿素(快速型和慢速型)、糊化淀粉尿素和大豆分离蛋白作为五种处理因子,采用单因子试验设计,利用活体外人工瘤胃产气法,研究不同形式的氮源对活体外瘤胃氨氮释放速度和发酵参数的影响.结果表明:在0～12h发酵过程中,不同形式氮源显著影响活体外瘤胃氨氮释放规律,其中两种包被尿素的氨氮浓度在各时间点均低于...     

共轭亚油酸及其在反刍动物中的研究进展

本文综述了共轭亚油酸的结构、来源、合成及其在反刍动物上的研究进展。     

花生油对绵羊体外瘤胃发酵指标的影响

本研究采用体外批次培养技术,选择3只安装有永久性瘤胃瘘管的绵羊为瘤胃液供体,以微晶纤维素为培养底物,培养瓶中花生油的添加量分别为0、5、10、15 mg培和20 mg,每个水平做3个重复,在培养4、8、16、24、36 h和48 h各时间.占'测定培养液中pH值、氨氮(NH3-N)浓度、总挥发性脂肪酸(TVFA)浓度和48 h纤维素消失率,从而筛选花生油在体外培养中适宜的添加量.结果表明:随着花生油添加水平的逐渐增加,培养液中pH值呈上升趋势,NH3-N浓度、TVFA浓度和48 h纤维素消失率逐渐降低.本试验中,在不影响瘤胃发酵的情况下花生油的最适宜添加量为5 mg.     

Effects of slaframine on ruminant digestive function: ruminal motility in sheep and cattle

Effect of purified slaframine (SF; 1-acetoxy-6-aminooctahydroindolizine), a parasympathomimetic secretagogue isolated from Rhizoctonia leguminicola, on ruminal motility was investigated in cattle and sheep. In trial 1, four ruminal cannulated wethers, fed a pelleted concentrate and hay diet, were injected intramuscularly with 0, 12, 24 and 48 micrograms SF/kg body weight (BW) in a 4 X 4 Latin-square design. Ruminal motility was recorded 1 h before and 1 to 2 h and 3 to 4 h after SF administration by measuring pressure changes exerted upon a fluid-filled, open-tipped catheter inserted into the dorsal sac of the rumen. The frequencies of both primary and secondary ruminal contractions were decreased as much as 20 to 78% with SF (P less than .05) depending upon the dosage level and time after administration. In trial 2, three ruminal-cannulated steers fed a concentrated diet were injected intramuscularly with 0, 12 and 24 micrograms SF/kg BW in a 3 X 3 Latin-square design. A water-filled balloon inserted into the cranial sac of the rumen was used to measure ruminal pressure changes 1 h before and 1 to 2 h, 3 to 4 h and 7 to 8 after SE administration. Frequency of primary and secondary ruminal contractions decreased with SF as much as 27 to 64% depending on the dosage level and time after administration. The frequency of secondary contractions increased 28% (P less than .05) as compared with control during the 7 to 8 h after administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protein supplement resistant against ruminal degradation as a factor improving utilization of urea in ruminant feeding

The metabolic and productive effects of the blood meal and formaldehyde (FA) treated casein supplements (5-10% of crude protein content) given with urea concentrates in sheep and fattening bulls were investigated. The blood meal has a similar composition of essential amino acids (EAA) to casein. The mean solubility of the FA treated casein and the blood meal after 6 hours of incubation in the sterilized rumen contents amounted 10.5% and 8.5% respectively. The average rumen ammonia concentration and plasma urea level was the highest in bulls fed urea ration without protected protein supplement. The supplementation of this ration with blood meal diminished the large daily fluctuation of plasma AA level and increased plasma EAA/NEAA ratio. The blood meal supplement improved the nitrogen retention in sheep (14%) and body gains in bulls (9%) but did not influence digestible coefficients and rumen protein synthesis in sheep.     

反刍动物亚急性瘤胃酸中毒的营养调控

反刍动物饲喂高谷物日粮时常发生瘤胃酸中毒现象,本文针对反刍动物亚急性瘤胃酸中毒的营养调控进行综述.     

Effects of dietary fiber and feeding frequency on ruminal fermentation, digesta water-holding capacity, and fractional turnover of contents.

To determine the effects of different sources of fiber and feeding frequency on digesta water-holding capacity (WHC; g H2O/g DM) and ruminal liquid contents, four ruminally fistulated Jersey steers were fed a 60:40 roughage-concentrate diet at 1.5 times NEm. Diets contained either sorghum silage (SS) or a 67:33 mixture of SS and soyhulls (SH) as roughage and were fed either once or 12 times daily, in a 2 x 2 factorial experiment with 15-d periods. Ruminal fluid was sampled at 2, 4, 6, 8, 10, 12, 16, 20, and 24 h after a dose of Co-EDTA on d 10 and analyzed for Co, VFA, ammonia, buffering capacity, and osmolality. Ruminal WHC, NDF, ADF, lignin, and starch were measured in samples obtained by ruminal evacuation at 3, 6, 12, and 24 h after feeding on d 11, 12, 14, and 15, respectively. Substitution of SH for SS decreased ruminal pH .32 units and dilution rate by 26.8% but increased total VFA by 10.9%, osmolality by 13.6%, and the fractional turnover rate (FTR) of ADF by 22.5% (P less than .05). Frequent feeding resulted in 4.7, 21.9, and 74.4% increases in total VFA and FTR of ruminal DM and starch (P less than .05), respectively. Interactions (P less than .05) were observed between dietary fiber source and feeding frequency for ruminal fluid molar percentage acetate to propionate ratio (A/P), liquid volume (evacuated), and WHC (kilograms). Substituting SH for SS decreased ruminal WHC (kilograms), liquid volume, and A/P only in steers fed once daily. Ruminal WHC (kilograms) was correlated positively with ruminal liquid volume but negatively with DM FTR. The dynamics of digesta WHC (kilograms) associated with dietary fiber source and feeding frequency suggest that it may influence the contribution of water and salivary secretions to ruminal liquid contents.