高山灌木和牧草缩合单宁含量季节变化动态研究

采用香兰素盐酸法分析了高寒草甸几种优势牧草和灌木中的可浸提缩合单宁含量季节变化动态.试验结果表明,线叶嵩草、阴山扁蓿豆、垂穗披碱草和鹅绒委陵菜等牧草和短叶锦鸡儿不含缩合单宁;珠芽蓼缩合单宁含量高,5个月的平均值为77.56 g/kg DM,7月高达120.2 g/kg DM;苔草显著低于珠芽蓼(p＜0.01),最高时也只有6.7 g/kg DM(7月);5种灌木缩合单宁含量各不相同,金露梅、红药柳、高山绣线菊、藏沙棘和鬼见锦鸡儿4个月的平均值分别为(g/kg DM)54.3、58.53、29.18、67.08和42.15,且随着季节推移,各灌木缩合单宁含量逐渐下降;而珠芽蓼和苔草从5月到7月逐渐上升,之后又开始下降.同时,分析了缩合单宁含量与植物的进化及家畜利用富含缩合单宁植物时应注意的事项.     

体外产气法评定天祝几种高山植物的抗营养因子及饲用潜力

比较和分析了6种富含单宁的家畜可饲高山植物粗蛋白、酸性洗涤纤维、粗灰分的含量,并对其酚类物质的含量进行了测定。结合体外产气技术(in vitrogas production method),对各种植物和添加聚乙烯二醇(PEG)的体外产气量和干物质降解率进行测定。结果表明,灌木粗蛋白含量较高,藏沙棘高达14.3%,缩合单宁含量随植物品种不同而变化,藏沙棘、金露梅和珠芽蓼含量分别为42.45,35.24,32.98 g/kg(DM)。添加PEG后,珠芽蓼、藏沙棘、金露梅和鬼箭锦鸡儿的产气量分别增加了36.9%,38.9%,16.4%和8.6%。     

高山草甸几种饲用灌木在牦牛瘤胃内的降解率

分析测定了高寒草甸几种饲用灌木的蛋白质、酸洗纤维和缩合单宁含量季节的变化动态,并利用3头安装了瘤胃瘘管的牦牛,采用尼龙袋技术(In sacco method)测定了几种灌木在牦牛瘤胃内的干物质降解特性。结果表明：灌木的蛋白质含量高,6月份金露梅、高山绣线菊、红药柳和鬼见锦鸡儿等植物分别为19．7％、22．0％、24．4％和24．0％;6月份缩合单宁合量分别为74．8g／kgDM、58．1g／kgDM、91．2g／kgDM和69．5g／kgDM。而且随着季节推移,蛋白质和缩合单宁含量都逐渐下降,而酸洗纤维含量随季节变化不明显。样品可溶性成分物理消失量大,培养4h出现较高消失率,一般达24％以上,48h时基本达50％以上。分析还表明降解常数与粗蛋白和缩合单宁含量成不显著的正相关关系,而与酸洗纤维含量成不显著的负相关关系。     

荒漠地区主要饲用灌木类植物酚类物质含量及动态变化

文章初步探讨了灌木类植物的酚类物质在不同生长期的含量变化,比较灌木类植物和紫花苜蓿的酚类物质含量及动态变化规律,为开发利用灌木类植物资源提供基础数据。研究结果表明:荒漠地区几种主要灌木类植物中总多酚、简单酚、单宁和缩合单宁的平均含量分别为75.76~101.78、12.98~19.88、61.07~86.09 g/kgDM和25.66～46.66 g/kgDM,其除了简单酚以外,上述物质在羊柴中含量最高,木地肤中含量最低。在生长期间灌木类植物总多酚、单宁和缩合单宁含量有"V"字型变化或随生长期逐渐上升,而且生长期间差异极显著,几种灌木酚类物质含量均高于紫花苜蓿。     

甘肃天祝高寒地区5种灌木中酚类物质含量的研究

对甘肃天祝金强河高寒地区5种灌木中的酚类物质含量进行了测定和比较分析。结果表明,不同的灌木品种其酚类物质的含量不同。藏沙棘总酚,单宁和缩合单宁的干物质含量均高于其他灌木,分别高达69.67,63.34和42.45 g/kg,而其简单酚的干物质含量最低,仅为4.27 g/kg。窄叶鲜卑木的酚类物质含量较低,与其他灌木相比差异极显著(P<0.01)。相关性分析表明,单宁和简单酚含量呈显著的正相关关系(r=0.94,P<0.01),与缩合单宁的相关系数为r=0.82(P<0.05),而简单酚与缩合单宁含量呈不显著的负相关关系。     

高寒草甸植被特征对模拟增温的响应——以青藏高原多年冻土区为例

采用红外辐射灯(infrared heater)模拟气候变暖背景,研究青藏高原多年冻土区高寒草甸优势植物种珠芽蓼(Polygonum viviparum)、美丽风毛菊(Saussurea superb)和黑褐苔草(Carex atrofusca)的生长发育及光合特性对气候变暖的短期响应及其差异性,旨在为评价草地生态系统的敏感性和脆弱性提供科学依据。结果表明,模拟增温W1(1.88℃)和W2(3.19℃)均可改变高寒草甸物种分布的频度和季节分布格局,并显著影响植被高度和光合色素含量,影响程度存在种间差异性。与不增温对照相比,W1增温下物种具有不同的响应,美丽风毛菊的高度、频度和叶绿素含量均呈下降趋势,而珠芽蓼和黑褐苔草均呈增加趋势。W2增温显著增加了珠芽廖和黑褐苔草的高度、频度和叶绿素含量(P0.05),却显著降低了美丽风毛菊的叶绿素a/b值(P0.05)。物种间光合特性存在显著差异(P0.05),样地间差异性表现更为突出,但增温处理间变化不明显。这说明增温可促进高寒草甸牧草类植物的生长发育,延长青草期,有利于牧业生产,但斑块状分布明显。     

利用体外产气法测定高山牧草和灌木的干物质降解率

用体外产气法测定了几种牧草和灌木的产气量,以及利用PEG测定了缩合单宁对产气量的影响作用。试验发现12h的产气量与48h的干物质降解率之间呈正相关关系,牧草与灌木的相关系数分别为0．814(P＜0．01)和0．378(P＞0．05)。产气量与缩合单宁含量呈不显著的负相关关系。当添加PEG后,样品12h和24h的产气量显著增加(P＜0．05)。添加PEG后,牧草24h(r＝0．993,P＜0．01)和36h(r＝0．956,P＜0．05)的产气量提高率与缩合单宁含量之间呈正相关关系。灌木产气量的提高率与缩合单宁含量也呈正相关关系,但不显著。说明植物中的缩合单宁对牦牛瘤胃微生物有一定的影响作用。     

不同添加剂对苜蓿与花生秧混合青贮体外发酵特性的影响

试验旨在研究不同添加剂对紫花苜蓿与花生秧混合青贮后体外发酵特性的影响，为添加剂在生产实践中的应用提供理论依据。处理组分别为对照组(CK)、1×10⁶ CFU/g FW(鲜重)植物乳杆菌添加组(Lp)、5 g/kg FW纤维素酶添加组(Ce)、1×10⁶ CFU/g FW植物乳杆菌+5 g/kg FW纤维素酶添加组(Lp+Ce)、40 g/kg DM单宁添加组(Ta)、1×10⁶ CFU/g FW植物乳杆菌+40 g/kg DM单宁添加组(Lp+Ta)、5 g/kg FW纤维素酶+40 g/kg DM单宁添加组(Ce+Ta)、5 g/kg FW纤维素酶+40 g/kg DM单宁+1×10⁶ CFU/g FW植物乳杆菌添加组(Lp+Ce+Ta)，室温贮藏45 d后，进行体外发酵试验，共8组。结果表明：各种添加剂处理对pH无显著影响(P>0.05)。与CK组相比，各组的氨态氮(NH3-N)含量显著降低，其中Ta组NH3-N含量显著低于Lp、Ce、Ce+Lp组，高于Ce+Lp、Ce+Ta、Ce+Lp+...     

氮素对羽叶决明缩合单宁及相关酶活性的影响

缩合单宁对牧草品质的影响极大,适量的缩合单宁含量对于提高牧草的利用率和营养品质非常重要。研究以豆科牧草羽叶决明Cassia nictitoms为材料,分析了氮素梯度处理后茎和叶中缩合单宁的含量及其生物合成酶二氢黄酮醇还原酶(DFR)活性的变化特征。结果表明,羽叶决明叶片的缩合单宁含量高于茎,随氮素的增加,叶片中缩合单宁含量从14.78%下降到1.14%;茎中从4.62%开始降低,达到0.98%后趋于稳定;DFR活性表现出与缩合单宁相似的变化规律,二者在叶和茎中都呈显著(P0.01)的二次曲线关系。植株粗蛋白含量测定发现,随氮素的增加粗蛋白含量无显著增加(P0.05)。因此,适当增加氮素的使用量可以达到减少缩合单宁含量,从而提高羽叶决明的利用率和营养品质。     

阿坝高原野生珠芽蓼果实能源价值评价

对阿坝州红原县、若尔盖县及松潘县珠芽蓼果实产量、总糖及能值三方面的能源价值评价结果表明,1)7个采样地珠芽蓼果实产量和总糖含量总体差异显著(P<0.001),3号采样地果实产量极显著高于其他采样地(鲜重117.222 g/m²、干重46.226 g/m²),总糖含量最高为5号采样地(54.16%),平均总糖含量49.73%;2号、3号和7号采样地珠芽蓼果实的能值大小没有呈现一定的规律性,平均能值15.85 MJ/kg。2)经相关性分析,果实干重与海拔呈显著负相关(P<0.05),与珠芽蓼盖度和地上现存量呈显著正相关(P<0.05),而各因素对果实总糖含量的影响不显著(P>0.05)。3)在不统计不同产量草地面积的情况下,果实年产量在红原县地区达17 387.81～105 674.34 t(鲜重),年产糖分8 646.96～52 551.85 t,在若尔盖地区达15 172.04～92 208.01 t(鲜重),年产糖分7 545.06～45 855.04 t,有望成为具有潜力的野生碳水化合物类能源植物。     

青藏高原黑褐苔草的抗寒性物质季节变化动态研究

测定了生长在青藏高原的黑褐苔草叶片中几种与抗逆性有关的生化物质含量的季节变化。结果发现:可溶性糖含量随生长的季节进程升高;脯氨酸含量在返青期最高,草盛期保持稳定,枯黄期下降;过氧化物酶(POD)和超氧物歧化酶(SOD)活性在草盛期最高,枯黄期最低;丙二醛(MDA)含量逐渐升高,表明黑褐苔草的抗性差异与高寒地区的特殊气候因素有关。     

合作市高寒草甸牧草生长期植被盖度、可食牧草产量及养分含量动态分析

为制定合理的高寒草甸保护利用规划,将"3S"技术与地面调查、实验室检测相结合,通过像元二分模型、估产建模和克里金插值等方法,研究摸清甘肃省合作市高寒草甸牧草生长期植被盖度、可食牧草产量及分级,牧草养分含量及动态变化规律。结果表明:2017年6-8月植被盖度及盖度级别,可食牧草平均鲜草产量和总鲜草产量均随生长期延续而增大。6、7、8月植被平均盖度分别为55.79%、72.69%和78.89%,平均鲜草产量分别为1 214.85、4 797.75和5 550.90 kg/hm^2,以7月增幅较大。6月Ⅱ级盖度草地占79.05%,7月Ⅱ级盖度下降52.61%、Ⅰ级盖度占比增加到45.03%,8月Ⅰ级盖度草地占77.34%;鲜草产量从6月的<1 500 kg/hm^2为主,向7月的3 000~4 500 kg/hm2和8月的4 500~6 000 kg/hm^2产量级转变。以8月总鲜草产量为基础的高寒草甸适宜载畜量为20.80万个羊单位。高寒草甸可食牧草CP和P含量随牧草生长期延续而降低,而EE、NDF、ADF和Ca含量增加。单位面积CP、EE、NDF、ADF产量7月最高,分别为165.51、27.77、569.40和246.02 kg/hm^2;Ca产量7-9月变化幅度较小,在0.052~0.059 kg/hm^2之间,P产量8月达最高,为0.024 kg/hm^2。     

Acceptance and digestibility of some selected browse feeds with varying tannin content as supplements in sheep nutrition in west Africa

In 1994 and 1995 leaves from 10 selected West African trees and shrubs with varying tannin content were tested to determine their suitability as an alternative and supplementary browse feed for West African dwarf sheep to improve productivity in small-scale holdings in Benin. Dry matter intake per kg metabolic body weight (DM g/kg W0.75) varied between the different browse feeds and between the different trials and ranged from zero (Leucaena leucocephala) up to 26.7 DM g/kg W0.75 (Margaritaria discoidea). The digestibility of the organic matter varied between 58.9% (L. leucocephala) and 68.2% (Mallotus oppositifolius). Agelaea obliqua showed the highest levels of total phenols (10.2%), tannin phenols (8.8%) and extractable condensed tannins (8.0%). Leaves from various browse feeds are a good and protein-rich supplementary fodder in addition to the grass Panicum maximum. However, feeding of A. obliqua and Cnestis ferruginea should be avoided due to toxic components.     

Chemical composition and nutritive value of four varieties of cassava leaves grown in South-Western Nigeria

The nutritive value of leaves of four varieties of cassava - MS 6, TMS 30555, Idileruwa and TMS 30572 was evaluated based on their chemical composition and in vitro fermentation. Crude protein (CP) contents of cassava leaves ranged from 177 to 240 g/kg dry matter (DM), with TMS 30555 showing the highest CP contents. Neutral detergent fibre (NDFom) and acid detergent fibre (ADFom) contents of cassava leaves ranged from 596 to 662 and 418 to 546 g/kg DM respectively. Condensed tannin (CT) and hydrocyanic acid contents ranged from 1.0 to 3.8 g/kg and 58.5 to 86.7 mg/kg DM respectively. The range of volatile fatty acids (VFA) in the supernatant after in vitro incubation of the cassava varieties was: acetate (14.7-31.5 mmol/l); propionate (4.5-6.3 mmol/l); butyrate (3.1-3.9 mmol/l); valerate (0.4-0.6 mmol/l); iso-butyrate (0.6-1.3 mmol/l); iso-valerate (1.1-1.9 mmol/l). The acetate:propionate ratio resulting from fermentation of TMS 30555 was higher(p < 0.05) than that of the other leaves. The highest in vitro gas production of 50.5 ml/200 mg DM was recorded for MS6 being higher (p < 0.05) than for TMS 30572, but similar to TMS 30555 and Idileruwa. The DM, CP, ADF and HCN contents of cassava leaves were positively correlated with gas production, while CT content was negatively correlated with gas production. The study showed that leaves of the varieties MS 6 and TMS 30555 are superior to the others in terms of CP and gas production indicating a higher digestibility and energy content and thus nutritive potential. They may therefore serve as supplements for ruminants fed on poor roughages.     

柠条对牛的饲用价值研究

柠条在北方旱区防风固沙、环境保护等生态建设中起着重要的作用,作为改善生态环境的先锋植物,在北方旱区已经大面积种植。柠条———作为耐牧植物,是夏秋季牛、羊等草食畜的良好饲料。本试验对柠条在冬春季节的饲料化开发利用上进行了探索性研究。结果表明:柠条无叶期枝条,同样具有一定的饲用价值:其代谢能(ME)为6.559MJ/kg.干物质);可消化总养分(TDN)达43.63%;泌乳净能(NEL)为3.265MJ/kg.干物质;每千克干物质中含奶牛能量单位(NND)为1.035。研究表明,柠条在饲料化开发利用方面前景广阔。     

Is the intrinsic potassium content of forages an important factor in intake regulation of dairy cows?

Hay from intensively managed grassland with high nutrient density and digestibility containing 29 g potassium/kg dry matter (DM) and hay from an alpine pasture, clearly lower in energy, digestibility and potassium (12 g/kg DM) were offered as sole feeds to 18 lactating dairy cows following a change-over arrangement within three periods of 21 days each (schedule either alpine-lowland-alpine or lowland-alpine-lowland hay). Faeces and urine were quantitatively collected over 7 days. Dry matter intake was similar and neutral detergent fibre (NDF) intake was higher with alpine than with lowland hay (1.57 kg/100 kg vs. 1.43 kg/100 kg body weight). Potassium intake was approximately three times lower with alpine than with lowland hay. Urinary water output was closely correlated with potassium intake. It was also correlated with DM intake but only in animals receiving lowland hay, while it remained independent from intake when alpine hay was fed. Plasma osmolality was lower when alpine hay was fed. As energy requirements were not covered with either diet, the lower NDF intake with lowland hay was assumed to have been caused by higher ruminal osmolality because of the higher intrinsic potassium concentrations of this hay type. Further studies are necessary to determine potassium levels critical for feed intake.