Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.     

恒河猴肾上腺皮质的显微与超微结构

应用光镜和透射电镜观察，恒河猴肾上腺皮质可分为球状带、束状带和网状带。其特点是：（1）被膜较发达，有时可伸入球状带将其细胞分隔为团块。（2）球状带有时呈指状指入束状带和网状带，其内可见嗜铬细胞；球状带细胞可分为明、暗2种类型，他们排列成团球状、滤泡状、索状和不规则形。（3）网状带较发达，有的可分为内、外2个区；有时网状带呈刺状伸入束状带；有时网状带细胞可见于被膜下或髓质内。（4）有时部分被膜连同皮质一起呈指状伸入髓质内。（5）皮质细胞均含丰富的溶酶体、线粒体和内质网，但不同部位的细胞所含的脂滴在数量、大小、形态和电子密度等方面存在差异。     

植物病原荧光假单胞杆菌数值分类研究

 采用数值分类法研究了来自21种寄主植物96个病原荧光假单胞菌菌株(包括5株非荧光菌)的分类问题。结果表明,所有参试荧光菌菌株可分成两大组,第一组(组I)生长较慢,精氨酸双水解酶呈阴性,营养谱窄,多数菌株不利用DL-苯丙氨酸,L-苯丙氨酸,L-羟脯氨酸,L-异亮氨酸,L-色氨酸,L-瓜氨酸,DL-nor-缬氨酸,L-胱氨酸,单宁酸和鼠李糖作为唯一碳源,不能利用天冬氨酸作为唯一碳源和氮源,而第二组(组Ⅱ)的菌株可利用这些化合物。组I的菌株可分为10个亚组(I₁-I₁₀),亚组与致病变种或命名种基本对应,与寄主来源密切相关;亚组间的区别在于它们利用底物的能力不同。组Ⅱ均具有精氨酸双水解酶,营养谱广泛。     

低聚糖对雏鸡大肠粪便NH3-N含量及肠道菌群的影响

试验选取1日龄罗曼蛋公雏250只，随机分为5组，试验组饲料或饮水中分别添加海藻糖(500mg／kg)、海藻胶(600mg／kg)、大豆寡糖(500mg／kg)、圆葱寡糖(500mg/d)。结果表明，四种低聚糖均可促进肠道乳酸菌及双歧杆菌的生长繁殖，对魏氏梭菌的生长呈现抑制作用。海藻糖、海藻胶对降低大肠粪便NH3—N含量效果不显著(P＞0．05)，而大豆寡糖效果显著(P＜0．05)，圆葱寡糖效果极显著(P＜0.01)。     

家蚕豆腐渣人工饲料及五龄期饲育研究

以３个栽培品种的冬芽为试验材料，分析了茎尖培养生长差异的生理原因．结果表明：添加果糖的效果优于蔗糖，而提高蔗糖浓度可以促进茎叶生长；不同品种茎尖的蔗糖酶活性存在较大差异，生长良好的品种（剑持）其蔗糖酶活性及酶蛋白含量高于生长较差的湖桑３２号和一之濑；茎尖内源激素含量及其比例差异明显．其中ＧＡ、ＡＢＡ含量及其比值剑持较高，其次为一之濑，湖桑３２号最低     

蜂蜜的矿物质与营养

等离子体光谱分析表明：研究的１０种蜂蜜均含有人体所需的多种矿物元素。人体血浆中Ｃｕ／Ｚｎ，Ｋ／Ｎａ，Ｃａ／Ｍｇ比与身体状况密切相关。研究表明荞麦蜜的Ｃｕ／Ｚｎ比最高，Ｋ／Ｎａ比也较高，而Ｋ／Ｎａ，Ｃａ／Ｍｇ比以枣花蜜为最高。食用蜂蜜的人将受蜂蜜中矿物元素的影响而改善这些价值，有益于健康。     

控制工程造价不是盲目压价

本文对工程造价管理角度进行了论述,从不同的角度分析了控制工程造价的方法,阐明如 何科学地控制工程造价。     

桉苗灰霉病初步研究

按苗灰霉病(Botrytis cinerea Pers.ex Fr.)是近年在云南省新发现的病害,过去未曾报道。该病多发生在按苗幼嫩的茎上部和叶片上,可造成按苗迅速死亡。早春连绵阴雨,气温较低,致使该病易造成流行,该病的流行也与管理措施密切相关。采取平衡施肥,加强苗期管理是最有效的预防措施。发病期可施用75％百菌清可湿性粉剂1:500倍;或70％敌克松可湿性粉剂与等量的50％多菌灵可湿性粉剂混用,稀释1000倍常量喷雾,每7～10天一次,连续喷2～3次,可有效地控制按苗灰霉病蔓延流行。     

盐分对碱茅种子发芽影响的机制

耐碱茅种子在盐（NaCl与Na2SO4）及干旱（PEG－6000模拟）胁迫下发芽及其机制的比较研究表明，种子发芽率随溶液渗透势的降低而下降，在等渗条件下三种溶液中的发芽率次序为Na2SO4＞NaCl＞PEG。NaCl与Na2SO4主要通过影响种子吸水量及对膜的毒性影响发芽，根据相关及通径分析结果，其机制为：（1）溶液渗透势及Na+浓度决定的种子吸水对发芽的直接正效应（通径系数0．73）；（2）溶液Na+浓度引起的膜毒性对发芽的直接负效应（－0．51）；（3）种子从溶液中吸收Na使种子吸水增加对发芽的间接正效应（0．30）及使膜毒性增大对发芽的间接负效应（－0．24）。