A comparative study on the rumen microbial populations,hydrolytic enzyme activities and dry matter degradability between different species of ruminant

A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly (P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6‐diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep (P < 0.01). Goat had the highest (P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals.     

外源寡糖对奶山羊免疫机能的影响

选用体况良好、年龄相近、体质量（32.80±2.45）kg、装有永久性瘤胃瘘管的崂山奶山羊6只,采用分期分组试验设计,分别饲喂添加1%（以有效含量计）甘露寡糖（MOS）、半乳甘露寡糖（GMOS）、果寡糖（FOS）、寡木糖（XOS）和异麦芽寡糖（IMO）的试验日粮,另设不添加寡糖的对照组。试验共分为4期,每期35d,其中预试期14d,正试期21d。结果表明：1）21d时,FOS组的血清碱性磷酸酶（AKP）含量显著升高（P〈0.05）,GMOS组的血清AKP、溶菌酶含量显著升高（P〈0.05）。2）21d时,FOS组、MOS组和GMOS组的血清免疫球蛋白A含量显著或极显著升高（P〈0.05或P〈0.01）;7、21d时,FOS组的血清免疫球蛋白G、M含量显著或极显著升高（P〈0.05或P〈0.01）;14、21d时,GMOS组的血清免疫球蛋白G、M含量显著或极显著升高（P〈0.05或P〈0.01）;7、14d时,MOS组的血清免疫球蛋白M含量极显著升高（P〈0.01）。3）7d时,FOS组血清白细胞介素-2、4、6含量显著或极显著升高（P〈0.05或P〈0.01）;7、21d时,GMOS组血清白细胞介素-2、6含量显著升高（P〈0.05）;14d时,FOS组和GMOS组血清白细胞介素-4含量显著升高（P〈0.05）。试验结果表明,不同外源寡糖对奶山羊有较好的免疫调节作用,其中,添加FOS和GMOS效果最好。     

不同居群狗牙根的叶片解剖结构比较研究

对20个不同生长环境的狗牙根叶片进行了比较解剖学的研究。结果表明,参试材料在角质层厚度、表皮细胞厚度、叶表皮细胞的长宽、气孔的大小及密度、叶片厚度、维管束个数及直径大小,机械组织厚度等方面有显著的差异。其中变异系数较大的是气孔密度及中脉维管束与上表皮间的机械组织厚度,气孔密度的变幅为77.49～335.46个/mm²,变异系数达36.93%,机械组织厚度的变幅为7.50～45.00μm,变异系数达64.20%。将测定的数量指标进行了聚类分析,20个不同居群的狗牙根可分为4大类。聚类结果与狗牙根的生境分布相互吻合。     

不同草种单播草坪蒸散量的研究

对草地早熟禾、多年生黑麦草、高羊茅、狗牙根、结缕草和野牛草6种常见草坪草草坪的蒸散量进行了研究,发现在充分灌水的条件下,冷地型草坪的蒸散量显著大于暖地型草坪(P<0.01);3种冷地型草坪间差异较小;暖地型草坪中狗牙根和结缕草的蒸散量显著高于野牛草(P<0.01)。限制灌水条件下,6种草坪的蒸散量差异均显著(P<0.05或0.01),其顺序为:高羊茅>早熟禾>黑麦草>狗牙根>结缕草>野牛草。通过充分灌水和限制灌水2个处理确定了6种草坪的年需水量范围。在不同水分梯度下,高羊茅的蒸散量随土壤含水量的减少而减少;狗牙根的蒸散量随土壤含水量的减少呈现降低的趋势。高羊茅和狗牙根蒸散量在一天内随温度的升高而增加,但温度维持在较高时由于气孔关闭导致蒸腾降低从而蒸散量降低。     

Propagation of bovine coronavirus in clones of the Caco-2 cell line showing different levels of alkaline phosphatase activity

The aim of the present study was to determine whether bovine coronavirus (BCV) has the ability to initiate infection in a human colon carcinoma cell line, Caco‐2, that has been established to spontaneously differentiate after confluence. When Caco‐2 cells were infected with BCV, a titer of 5.5 × 10⁶ plaque‐forming units (p.f.u.)/mL was found in the culture supernatant at 5 days postinfection. Two clones, Caco‐2/CA1 and Caco‐2/CA2, were then isolated by monitoring alkaline phosphatase (ALP) and cell proliferation activities. The ALP activity level of CA1 cells was significantly higher than that of CA2 cells, while the level of cell proliferation activity of CA1 was significantly lower than that of CA2. When CA1 and CA2 cells were infected with BCV at confluence, virus hemagglutination (HA) was detected in the culture supernatant at 5 days postinfection for CA1 cells and at 8 days postinfection for CA2 cells. Thus, BCV propagation was substantially delayed in CA2 cells, suggesting that a cellular factor(s) that appears at the differentiation stage may control BCV propagation. BCV‐susceptible CA1 and CA2 cells showing different levels of ALP activity would be useful for further experiments to elucidate the mechanism of BCV propagation.     

高脂饲料对细鳞鱼稚鱼刷状缘膜水解酶发育的影响

试验评价了蛋白质含量为48%时,脂肪含量分别为15%、20%、25%、30%的饲料对开口后20～60 d的细鳞鱼稚鱼肠道水解酶-γ-谷氨酰肽转移酶、碱性磷酸酶活性发育的影响。结果表明,适度的饲料脂肪含量可以提高水解酶活性,并强于生物饵料,促进了肠道对营养物质的消化。饲料脂肪为20%～30%的水平时,水解酶的活性相对较高。     

致羔羊脑炎肠球菌与羔羊正常菌群肠球菌生物学特性的比较

对致羔羊脑炎肠球菌和羔羊正常菌群肠球菌进行培养特性、生化特性、溶血特性、药物敏感性以及拥有毒力因子基因种类与分布进行比较,结果表明2种不同来源羔羊肠球菌的培养特性和生化特性基本一致.致病菌均对链霉素、庆大霉素、红霉素等抗生素耐药,1株正常菌对四环素、红霉素及链霉素耐药.11株致病性肠球菌中有5株菌同时检测到esp、cyIA、asa1、ace、efa、EF0591和EF3314等7种毒力因子基因,2株菌没有检测到其中任何毒力因子基因.30株正常菌有3株菌存在gelE和EF3314,l株菌同时存在gelE、EF3314和asa1 3种毒力因子基因.正常菌群株3种毒力因子基因片段序列与GenBank中登录的相应序列同源性在95%以上,与致病株相应序列同源性在96%以上.致病菌能导致小鼠死亡,而正常菌群肠球菌则不能引起小鼠的死亡.     

Influence of graded levels of calcium and vitamin K in the diets of laying hens during the growing phase and their effects on the laying phase

The aim of this study was to evaluate the effect of dietary supplementation of vitamin K (vit K) and Ca in the diets of laying hens on bone and blood parameters and performance during the growing phase and the effects on the laying phase up to 32 weeks. The study utilized 120 Hy‐Line W‐36 pullets in the growing phase (13–18 weeks), 80 laying hens in the production phase (20–32 weeks), distributed in a completely randomized design in a 2 × 5 factorial arrangement, two levels of Ca (0.8 and 1.4%) and five levels of vit K supplementation (0, 2, 8, 16 and 32 mg/kg) with four experimental units. An experimental diet was fed during the growing phase, and the commercial diet was fed during the production phase and were analysed for biochemistry and bone variables at 18 and 32 weeks. In pullets, a significant interaction of levels of vit K and Ca was observed for total serum calcium (mg/dl), Seedor index, Ca in the bones (%) and medullary bone (%). Pullets at 18 weeks of age, receiving diets with 1.4% Ca, displayed a quadratic effect of vit K with better results for these variables with 17.86, 14.59, 14.48 and 16.80 mg/kg of vit K, respectively. For level 0.8% Ca no effect of vit K was observed. The treatments during the growing phase had no effect on egg production, performance and biochemistry serum until 32 weeks. Medullary bone (%), there was a significant interaction for 1.4% Ca and a quadratic effect for vit K, with greater medullary bone areas observed with 6.09 mg/kg vit K in the diet. Supplementation with vit K in a diet with 1.4% Ca during the growing phase allowed for an increase in the area of medullary bone at 18 weeks, which was maintained until 32 weeks.     

假苍耳不同部位水浸提液对5种土著植物化感作用的研究

为探究外来植物假苍耳对土著植物种子萌发和幼苗生长是否存在化感作用,分别利用其水浸提液处理5种土著植物种子。结果显示,假苍耳不同部位浸提液存在不同程度化感作用,且其不同部位化感作用强度不同,叶浸提液抑制作用最强。从叶中分离出的3种组分中中性组分化感效应强于酸性和碱性组分。不同的土著植物对假苍耳同一部位浸提液敏感程度也不同,狗尾草和苋种子萌发对假苍耳不同部位浸提液均表现敏感,大籽蒿、藜、稗对假苍耳不同部位浸提液则表现出低促高抑的趋势。     

4种结缕草光合特性及叶绿素含量的比较研究

以结缕草属4个不同种为试验材料,采用叶绿素测定仪以及光合测定仪,测定4种结缕草光合特征参数以及叶绿素含量。结果表明:(1)4种结缕草叶绿素含量由大到小依次为:日本结缕草,中华结缕草,沟叶结缕草,细叶结缕草;(2)日本结缕草和沟叶结缕草的光补偿点(LCP)为40μmol/(m2.s),接近于自然光照条件下阳性植物的光补偿点30μmol/(m2.s);(3)中华结缕草和细叶结缕草的LCP较高,为80μmol/(m2.s),光饱和点(LSP)都平均为1200μmol/(m2.s);(4)4种结缕草的表观量子效率(AQY)与自然光照条件下植物的AQY(0.03~0.06 mol/mol)一致,但是中华结缕草却显著高于其他3种,因此,可初步推断结缕草为阳性、且耐荫性较强的草坪草,并且中华结缕草以其优异的表现成为亚热带地区草坪草建坪中的最佳草种。     

假苍耳不同部位水浸提液对五种十字花科植物化感作用的研究

探讨假苍耳根、茎浸提液对萝卜、白菜、油菜、芥菜、甘蓝5种十字花科植物化感效应和作用规律。本试验采用室内生物学测定法,研究不同浓度(10、20、30、40 g·L^-1)假苍耳不同部位浸提液对5种十字花科植物种子的萌发及幼苗生长的影响,阐明假苍耳浸提液对5种十字花科植物的化感作用及作用机制。结果表明:假苍耳根、茎浸提液对5种十字花科植物发芽率、发芽势、发芽指数、活力指数、根长、苗高、苗鲜重具有显著的化感作用(P<0.05),且5种植物之间存在一定的差异,对萝卜、白菜、油菜总体趋势表现为“低促高抑”的双重效应,而对芥菜、甘蓝表现为抑制作用;不同部位浸提液对5种十字花科植物抑制作用强弱茎浸提液>根浸提液,说明假苍耳茎浸提液中含有抑制5种植物种子萌发及幼苗生长的主要化感物质;随着浸提液浓度升高,假苍耳对十字花科植物化感作用增强。综合化感指数评价结果显示,假苍耳植株浸提液对供试植物种子萌发和幼苗生长均有显著影响。     

科尔沁沙地70种植物繁殖体形状比较研究

研究了科尔沁沙地70种植物的繁殖体(31种为种子,39种为果实)形状。用繁殖体三维(长、宽、高)的方差衡量繁殖体形状。方差越小,繁殖体越接近圆球形;方差越大,繁殖体越细长或扁平。研究结果表明,1)所量测的70种植物的繁殖体(种子或果实)形状差异很大,最小的方差不足0．03,最大的超过0．18。2)大部分一年生杂草的种子繁殖体近似于圆球形。3)黄蒿、马齿苋、碱地肤、狼尾花、灰绿藜、刺沙蓬、菟丝子、大籽蒿、狗尾草的繁殖体比较接近圆球形(方差小于0．09),它们可能具有持久种子库。4)萝摩科植物萝摩、杠柳、细叶白前繁殖体具绢毛;菊科植物女菀、飞廉、黄金菊、山莴苣、苣荬菜和夹竹桃科植物罗布麻有冠毛;石竹科植物石竹和鸢尾科植物野鸢尾有翅;香蒲科植物小香蒲有宿存花柱;可能这些植物都可被风传播。糙隐子草、披碱草、水稗草、牛鞭草、冠芒草具芒,它们可能具有固结自身的作用;苍耳、雾冰藜、鹤虱带钩或刺,易于被动物传播。5)草甸植物野豌豆、海滨天冬、小黄花菜作为传播体的种子较圆;草甸植物女菀、山莴苣、黄金菊、披碱草、野古草、牛鞭草、狼尾草作为传播体的果实扁平或细长;流沙上的先锋植物或沙生系列演替前期植物沙蓬、刺沙篷、乌丹蒿、差巴嘎蒿、狗尾草、雾冰藜、东北木蓼、山竹子等的繁殖体多数偏离圆球形程度较大。     

Effects of ethylenediaminetetraacetic acid on phytate phosphorus utilization and efficiency of microbial phytase in broiler chicks

Previous studies have suggested that organic acids may improve P utilization in animals. To evaluate the ability of ethylenediaminetetraacetic acid (EDTA) to improve phytate P utilization and the possible synergistic effect between EDTA and microbial phytase (MP) an experiment was conducted using 360 Ross 308 broiler chicks. The experiment was carried out using a completely randomized design with a 3*2 factorial arrangement (0, 0.1 and 0.2% EDTA and 0 and 500 IU MP). Four replicate of 15 chicks per each were fed dietary treatments including (i) P-deficient basal diet [0.2% available phosphorus (aP)] (NC); (ii) NC + 500 IU MP per kilogram of diet; (iii) NC + 0.1% EDTA per kilogram of diet; (iv) NC + 0.1% EDTA and 500 IU MP per kilogram of diet; (v) NC + 0.2% EDTA per kilogram; and (vi) NC + 0.2% EDTA + 500 IU MP per kilogram of diet. Weight gain (WG), feed efficiency and serum Ca, P and alkaline phosphatase (ALP) were assessed. Addition of 0.2% EDTA to low aP diets resulted in significantly lower feed consumption (FC) and WG, but 0.1% EDTA did not depress WG compared to NC. Phytase supplementation of P-deficient diets significantly improved WG and feed efficiency, but it had no effect on FC. Microbial phytase supplementation significantly decreased ALP concentration. Results obtained in our study suggest no synergistic effect between phytase and EDTA in broiler chicks.     

Effects of pasteurella haemolytica leukotoxin on neutrophils from white-tailed deer and several exotic ruminant species

Pasteurella haemolytica leukotoxin is a pore-forming cytolysin which acts as a virulence factor in pasteurellosis of domestic ruminants. Leukocytes from cattle, sheep and goats are susceptible to leukotoxin-induced lysis; however, leukocytes from non-ruminant species so far tested are resistant to leukotoxin-induced lysis. Neutrophils obtained from three white-tailed deer, four Saiga antelope, an Addra gazelle, a Grant's gazelle and a Sable antelope were tested for susceptibility to the lytic effects of P. haemolytica leukotoxin using lactate dehydrogenase release. Results were compared to those obtained using neutrophils from a steer and cultured bovine lymphoma cells. Neutrophils obtained from all these ruminants, except the Addra gazelle, were susceptible to P. haemolytica leukotoxin. Individual variation among the Saiga and the deer did not appear to be due to the percentages of neutrophils or the percentage of contaminating erythrocytes in the cell preparations.     

乳制品中碱性磷酸酶检测的影响因素及控制措施

牛奶中含有大量的碱性磷酸酶（ALP）,由于其热稳定性略高于乳中的大部分致病微生物,比如结核杆菌、李斯特菌等,因此,乳品企业将其作为巴氏杀菌热处理评估的活性指标。但其不但易受到牛奶成分,尤其乳脂肪的影响,而且牛奶中微生物内源性ALP和贮存过程中ALP复活均会影响最终结果的判定。本文对影响ALP检测的影响因素进行分析,并就检验过程中人员培训、设备选定、检验比对、数据库建立等方面提出相关控制措施,确保检验结果的准确性。     

Influence of different dietary zinc levels on cashmere growth,plasma testosterone level and zinc status in male Liaoning Cashmere goats

The experiment was conducted to investigate the influence of different levels of zinc (Zn) on cashmere growth, plasma testosterone and Zn profile in male Cashmere goats. Twenty‐eight male Liaoning Cashmere goats, 3 years old and body weight at 56.2 ± 2.45 kg, were assigned to four groups. The animals were fed a basal diet containing of 45.9 mg Zn/kg dry matter (DM) basis and supplemented with 0, 20, 40 or 80 mg Zn (reagent grade ZnSO₄·7H₂O) per kg DM for 90 days. There was no significant effect on growth and diameter of cashmere fibre for Zn supplemented in diets. However, the length and growth rate of wool were improved (p < 0.05) with dietary Zn. The length and growth rate of wool were higher (p < 0.05) for the groups supplemented with 40 or 80 mg Zn/kg DM compared with that of 20 mg Zn/kg DM treatment group. Plasma testosterone concentration was increased for Zn supplemented in diets, and the testosterone concentration was higher (p < 0.05) in goats fed on the diet supplemented with 40 or 80 mg Zn/kg DM compared with those fed on basal diet. Plasma Zn concentrations increased (p < 0.05) with increasing dietary Zn and supplemented with 40 and 80 mg Zn/kg DM groups improved plasma Zn concentration (p < 0.05) more than 20 mg Zn/kg DM group. Fibre Zn content was higher (p < 0.05) in groups supplemented with 40 or 80 mg Zn/kg DM compared with control group, but no difference between Zn‐supplemented groups (p > 0.05). The activity of plasma alkaline phosphatase was increased (p < 0.05) due to dietary Zn supplementation; however, no difference was found between supplemented treatment groups (p > 0.05). In conclusion, Zn content (45.9 mg Zn/kg DM) in control diet was insufficient for optimal wool growth performance, and we recommended the level of dietary Zn for such goats is 86 mg/kg DM during the breeding season and cashmere fibre growing period.     

In Vitro Effects of Acellular Milk on the Bactericidal Components of Caprine Polymorphonuclear Neutrophils

The effects of acellular milk on the activity of the microbicidal cationic enzymes of the polymorphonuclear cells of goats were studied in an attempt to explain the phenomenon by which PMN functions fail in mastitis. Assays were undertaken on the myeloperoxidase, lysozyme and elastase activities in a polymorphonuclear cell (PMN) lysate, both in the presence and absence of acellular milk from homologous species. There was a significant decrease (p<0.05) in the activity of lysozyme, myeloperoxidase and elastase in the presence of acellular milk. Superoxide and H₂O₂ production following activation of caprine PMNs by lipopolysaccharide (LPS) was significantly reduced (p<0.05) in the presence of acellular milk. Thus, the microbicidal function of PMNs is significantly impaired in the presence of acellular milk and this may contribute to the development of mastitis in dairy animals.