不同植酸酶的热稳定性和生物学活性比较

试验评定了3种植酸酶产品的制粒稳定性,并通过动物试验评价了其在肉仔鸡日粮中的生物学活性。1日龄AA肉仔鸡770只,随机分为11个处理,分别采食添加不同剂量植酸酶(500、1 0002、000 U/kg)的低磷日粮。结果表明,产品A植酸酶的热稳定性明显优于产品B和产品C。在90℃和95℃制粒,产品A的存留率分别为96.3%和90.7%;产品B和C的存留率分别为26.4%、24.2%和12.6%、14.2%。采食低磷负对照日粮的肉仔鸡生长性能显著低于正对照日粮组(P<0.05)。在低磷日粮中添加植酸酶显著提高了肉仔鸡生长性能(P<0.05);肉仔鸡的生产性能随植酸酶的添加量增加而提高,植酸酶产品A趋势明显,添加量由500 U/kg提高到1 000 U/kg和2 000 U/kg,肉仔鸡体增重分别提高3.7%和6.1%,料重比降低3.5%和5.0%。根据配方中植酸磷的含量,植酸酶的添加量可由传统的500 U/kg提高到1 000 U/kg及以上。     

新型耐热植酸酶对肉仔鸡营养物质表观消化率及胫骨灰分含量的影响

试验在低磷日粮中分别添加普通植酸酶与耐高温植酸酶,研究两种植酸酶对肉仔鸡营养物质表观消化率及胫骨灰分含量的影响。选用4 800只1日龄AA肉仔鸡,随机分为6个处理,每个处理设5个重复。试验分2期进行,1~3周和4~6周。对照组饲喂基础日粮,处理1组降低基础日粮的磷水平,处理2组与处理3组分别在其基础上添加普通植酸酶500、2 000 U/kg,处理4组和处理5组分别添加耐高温植酸酶250、500 U/kg。结果表明:①当降低基础日粮中磷添加水平时,降低了磷的表观消化率;在此基础上添加500~2 000 U/kg普通植酸酶或250~500 U/kg耐热植酸酶,显著提高了磷的表观消化率,且超过了对照组,其中以250~500 U/kg耐热植酸酶与2 000 U/kg普通植酸酶效果理想。降低磷添加水平或添加不同来源植酸酶对粗蛋白质和钙的表观消化率基本没有影响;②当降低基础日粮中磷添加水平时,显著降低了胫骨灰分和磷的含量(P<0.05),同时钙含量呈降低趋势(P>0.05);在此基础上添加500~2 000 U/kg普通植酸酶或250~500 U/kg耐热植酸酶,胫骨灰分和钙、磷的含量恢复到或超出对照组水平。     

植酸酶对提高肉仔鸡日粮中钙、磷利用率的研究

将试验肉仔鸡随机分成4组,每组设3个重复,每个重复20只。Ⅰ组为不添加植酸酶的基础日粮对照组;Ⅱ组为每千克日粮添加500U植酸酶替代基础日粮中0.09%的无机磷试验组;Ⅲ组为每千克日粮添加500U植酸酶替代基础日粮中0.11%的无机磷试验组;Ⅳ组为每千克日粮添加500U植酸酶替代基础日粮中0.13%的无机磷试验组。试验按0～3周龄和4～6周龄两个阶段进行。试验结果表明:在肉仔鸡玉米-豆粕型日粮中添加0.01%的植酸酶(活性为5000U/g)替代日粮中0.12%的钙和0.11%的无机磷可显著提高肉仔鸡的生长性能,并能取得最佳的经济效益,为最适替代比例。     

新型耐热植酸酶对肉仔鸡生长性能及血清生理生化指标的影响

旨在通过饲喂肉仔鸡添加普通植酸酶与耐高温植酸酶的日粮,比较2种植酸酶对肉仔鸡生产性能及血清生理生化指标的影响。选用4 800只1日龄AA肉仔鸡,随机分为6个处理,每处理5个重复。试验分2期进行,1～3和4～6周。试验对照组饲喂基础日粮,试验1组降低基础日粮磷的水平,试验2组与3组分别在试验1组的基础上添加普通植酸酶500和2 000U.kg-1,试验4组和5组分别添加耐高温植酸酶250和500U.kg-1。结果表明:(1)当降低基础日粮中磷添加水平时,日增重显著下降(P<0.05),料重比提高;在此基础上添加植酸酶,日增重提高,料重比下降,甚至优于对照组。从生长性能指标分析来看,250～500U.kg-1耐热植酸酶与2 000U.kg-1普通植酸酶效果相当,优于试验2组;(2)当降低基础日粮中磷添加水平时,血清磷水平显著降低,血清碱性磷酸酶活性显著提高;在此基础上添加植酸酶,血清磷水平和碱性磷酸酶活性恢复到对照组水平。对血清总蛋白、球蛋白、白蛋白、谷草转氨酶、谷丙转氨酶和钙含量等指标含量基本没有影响;(3)不同日粮处理对T4、T3、生长激素、胰岛素样生长因子Ⅰ、甲状旁腺激素和降钙素均没有显著性影响(P>0.05);与对照组相比,胰岛素样生长因子Ⅰ在试验组1呈降低趋势(P>0.05),而各植酸酶添加组呈提高趋势。本试验条件下,发现在低磷日粮中添加新型耐热植酸酶可以显著提高肉仔鸡的平均日增重,降低料重比;对于血清生理生化指标,2种植酸酶添加效果无显著差异。     

小麦-杂粕型饲粮中添加木聚糖酶和植酸酶对肉仔鸡生长及饲料利用的影响

为了探讨小麦和菜籽粕等非常规饲料资源在肉仔鸡生产中的应用,并降低磷添加水平以减少环境污染,试验选取体重相近的1日龄柳州麻花鸡150只,随机分成4组:对照组、木聚糖酶组、低磷植酸酶组、低磷复合酶组,各组雏鸡分别饲喂基础饲粮(小麦-杂粕型饲粮)、基础饲粮+木聚糖酶1 000 U/kg、75%有效磷基础饲粮+植酸酶900 U/kg、75%有效磷基础饲粮+植酸酶900 U/kg+木聚糖酶1 000 U/kg。每组设3个重复,每个重复10～15只鸡,试验期21 d。测定每组鸡的采食量和体重,计算每组鸡的日增重、日均采食量、料重比。结果:基础饲粮+木聚糖酶1 000 U/kg可显著提高肉仔鸡的体重和日增重(P0.05);75%有效磷基础饲粮+植酸酶900 U/kg的肉仔鸡增重、采食量和饲料转化率与对照组相近(P0.05);75%有效磷基础饲粮+植酸酶900 U/kg+木聚糖酶1 000 U/kg并不能进一步促进肉仔鸡生长和提高饲料转化率。结论:在小麦-杂粕型饲粮中添加木聚糖酶1 000 U/kg可显著提高肉仔鸡生长性能;植酸酶900 U/kg可替代饲粮中25%有效磷,而不影响肉仔鸡生长。     

植酸酶提高肉鸡“玉米-豆粕”型日粮中钙磷利用率的研究

将240只肉仔鸡按饲养试验随机分成四组,每组设三个重复,每个重复20只.Ⅰ组为不添加植酸酶的基础日粮对照组;Ⅱ、Ⅲ、Ⅳ组为试验组,每千克基础日粮添加500 U植酸酶分别替代日粮中0.09%、0.11%和0.13%无机磷.试验按0～3周龄和4～6周龄两个阶段进行.结果表明:在肉仔鸡"玉米-豆粕"型日粮中添加0.01%的植酸酶(活性为5000U/g)替代日粮中0.12%的钙和0.11%的磷可显著提高鸡只的生长性能.     

日粮磷水平及磷限制日粮中添加不同浓度植酸酶对肉用仔鸡生长性能影响的研究

通过对高热稳定性、高耐酸性植酸酶生产价值的验证,研究了不同梯度日粮磷水平及磷限制日粮中添加不同浓度植酸酶对肉用仔鸡生长性能的影响。选择1日龄的AA白羽肉鸡(♂)800只,随机分为8个处理组,每组10个重复,每个重复10只鸡。处理组1为日粮正常组,基础日粮中有效磷的含量为0.45%;处理组2、3和4为日粮有效磷限制组,分别对日粮中有效磷的含量限制为0.35%,0.3%和0.25%。在处理组4的日粮基础上,分别对处理组5、6和7添加250U/kg,500U/kg和1000U/kg三个浓度梯次的植酸酶A,对处理组8添加100U/kg浓度的植酸酶B。试验期18d。结果表明,日粮有效磷限制组(处理组2、3和4)的肉用仔鸡18日体重、平均日采食量和料肉比等指标全都低于日粮正常组(处理组1),差异显著(P0.05);根据日粮中不同浓度植酸酶的添加,18日龄内,肉用仔鸡的平均体重(R2=0.6241)和料肉比(R2=0.9383)均呈现线性增长,同时,植酸酶B添加组(处理组8)的日采食量和日增重均优于植酸酶A添加组(处理组5、6和7)(P0.05)。因此,植酸酶可以有效的缓解日粮中有效磷不足对肉用仔鸡生长性能的影响,植酸酶B饲用效果优于植酸酶A。     

饲喂未添加无机磷的低磷日粮添加植酸酶对肉仔鸡生长性能和磷利用的影响

1、用3个试验测定未添加无机磷的低磷日粮,添加真菌植酸酶(来自黑曲霉)对肉仔鸡生长和磷利用率的影响。 2、添加不同水平的植酸酶(125,250或500PU/Kg日粮)显著提高生长率与采食量,中 等程度提高饲料转化率。 3、鸡生长性能的改善与日粮磷利用增高相关。饲喂植酸酶处理日粮鸡血浆无机磷浓度和胫骨灰百分比显著提高,磷的表观利用率得到改善,粪便中磷浓度降低(试验1,P<0.05)。 4、结论是在肉仔鸡的一种实际日粮中含有植酸酶时,允许减少或不添加无机磷盐。     

植酸酶和复合酶对肉鸡生产性能及氮、磷利用的影响

选用288只1日龄AA肉公鸡,随机分成4个处理组,每个处理设6个重复,每个重复12只鸡。试验日粮分别为:(1)低磷、低蛋白日粮(双低对照组);(2)低磷、低蛋白日粮+500PTU/kg植酸酶;(3)低磷、低蛋白日粮+500PTU/kg植酸酶+0.5g/kg复合消化酶(折合纤维素酶1500U/kg、木聚糖酶11500U/kg、α-半乳糖苷酶1000U/kg、酸性蛋白酶1000U/kg);(4)正常营养水平日粮(普通对照组)。结果表明:植酸酶或植酸酶+复合酶的添加显著(P<0.05)提高了肉鸡日增重和日采食量,达到、甚至趋向于超过普通对照组(P>0.05);显著(P<0.05)提高了肉鸡氮、磷利用率,进而大幅度降低氮、磷排放量。     

植酸酶和复合酶对肉鸡生产性能及氮、磷利用的影响

选用288只1日龄AA肉公鸡,随机分成4个处理组,每个处理设6个重复,每个重复12只鸡.试验日粮分别为(1)低磷、低蛋白日粮(双低对照组);(2)低磷、低蛋白日粮+500PTU/kg植酸酶;(3)低磷、低蛋白日粮+ 500PTU/kg植酸酶+ 0.5g/kg复合消化酶(折合纤维素酶1500 U/kg、木聚糖酶11500 U/kg、α-半乳糖苷酶1000 U/kg、酸性蛋白酶1000 U/kg);(4)正常营养水平日粮(普通对照组).结果表明植酸酶或植酸酶+复合酶的添加显著(P<0.05)提高了肉鸡日增重和日采食量,达到、甚至趋向于超过普通对照组(P>0.05);显著(P<0.05)提高了肉鸡氮、磷利用率,进而大幅度降低氮、磷排放量.     

Evaluation of lysozyme and lactoferrin in lacrimal and other ocular glands of bison and cattle and in tears of bison

OBJECTIVE: To evaluate lactoferrin and lysozyme content in various ocular glands of bison and cattle and in tears of bison. SAMPLE POPULATION: Tissues of ocular glands obtained from 15 bison and 15 cattle and tears collected from 38 bison. PROCEDURE: Immunohistochemical analysis was used to detect lysozyme and lactoferrin in formalin-fixed, paraffin-embedded sections of the ocular glands. Protein gel electrophoresis was used to analyze ocular glands and pooled bison tears by use of a tris-glycine gel and SDS-PAGE. Western blotting was used to detect lactoferrin and lysozyme. RESULTS: Immunohistochemical staining for lactoferrin was evident in the lacrimal gland and gland of the third eyelid in cattle and bison and the deep gland of the third eyelid (Harder's gland) in cattle. Equivocal staining for lactoferrin was seen for the Harder's gland in bison. An 80-kd band (lactoferrin) was detected via electrophoresis and western blots in the lacrimal gland and gland of the third eyelid in cattle and bison, Harder's glands of cattle, and bison tears. An inconsistent band was seen in Harder's glands of bison. Lysozyme was not detected in the lacrimal gland of cattle or bison with the use of immunohistochemical analysis or western blots. Western blots of bison tears did not reveal lysozyme. CONCLUSIONS AND CLINICAL RELEVANCE: Distribution of lactoferrin and a lack of lysozyme are similar in the lacrimal gland of cattle and bison. Differences in other tear components may be responsible for variability in the susceptibility to infectious corneal diseases that exists between bison and cattle.     

桑树的遗传变异特点及在品种选育中的应用

我国具有悠久的桑树栽培历史,拥有3 000余份桑树种质资源,分属15个桑种和4个变种,并逐渐形成适应不同生长环境的8个生态类型。依据已有的研究结果,综述桑树遗传变异的特点包括:广泛分布、自然有性杂交和异花授粉以及缺乏稳定性选择等,促进了桑树的突变发生,形成遗传变异的多样性;无性繁殖方式产生了丰富的无性系变异;性状遗传值中非加性效应占有较大比例;无性系品种间杂种一代存在复杂的多样性分离和经济性状的普遍退化;存在丰富的多倍体系列和普遍的混倍现象等。对桑树品种选育研究提出建议:基于桑树的高度杂合习性,不仅要重视研究不同品种中加性效应在遗传值中所占比率,更要研究非加性效应所占比率及充分利用的方法;基于桑树遗传变异的多样性和丰富的无性系变异,加强无性系和田间选优育种;利用桑树混倍现象,将培育多倍体特别是三倍体品种作为一条有效的多倍体育种途径。     

Housing of dogs and cats in shelters and kennels in Switzerland

The study deals with the situation regarding housing of dogs and cats in Swiss shelters and kennels. In shelters, dogs were mainly held inside a cubicle with a small outside yard. In kennels, housing of dogs took place mainly in inside rooms. Usually two or three dogs were kept together. Cats were held in rooms, with or without outside yards, mainly in groups; no establishment preferred exclusively the housing in cubicles. Shelters received on average 183 dogs and 262 cats each year. Among them, about a third were lost animals while the remaining ones were relinquished. The study highlights some possibilities for improvements and the great diversity of the establishments regarding their size, infrastructure, housing conditions and aims.     

Ecology and epidemiology of anthrax in cattle and humans in Zambia

Anthrax is endemic in Western and North-western Provinces of Zambia. The disease occurs throughout the year and impacts negatively on the economy of the livestock industry and public health in Zambia. During 1989-1995, there were 1626 suspected cases of anthrax in cattle in Western province and of these 51 were confirmed. There were 220 cases of human anthrax cases in 1990 alone and 248 cases during 1991-1998 with 19.1% and 7.7% case fatality rates, respectively. Interplay of the ecology of affected areas and anthropogenic factors seem to trigger anthrax epidemics. Anthrax has drawn considerable attention in recent years due to its potential use as a biological weapon. In this paper, the history, current status and approaches towards the control of the disease in Zambia are discussed. Quarantine measures restrict trade of livestock and exchange of animals for draught power resulting in poor food security at household levels. Challenges of anthrax control are complex and comprise of socio-political, economical, environmental and cultural factors. Inadequate funding, lack of innovative disease control strategies and lack of cooperation from stakeholders are the major constraints to the control of the disease. It is hoped that the information provided here will stimulate continued awareness for the veterinary and medical authorities to maintain their surveillance and capabilities against the disease. This may lead to a culminating positive impact on livestock and human health in the southern African region.     

Pharmacokinetics of penicillin-G in ewes and cows in late pregnancy and in early lactation

Concentrations of penicillin-G in serum were determined after single intravenous doses of potassium penicillin-G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin-G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model-independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug.     

Variation in quantity and quality of native forages and grazing behavior of cattle and goats in Tanzania

The study was conducted to assess the effects of seasonal variation in the quality and quantity of pasture and management of livestock exclosures (ngitili) on the grazing behavior of cattle and goats. The study was 2×2×2 factorial design with three independent variables: season (Dry or Rainy), ngitili management (Private or Communal) and animal species (Cattle or Goats). Focal and scan observation methods were used to record different behavioral activities. Vegetation attributes from the study areas were measured in two consecutive seasons. Most key forage species had significant higher crude protein (CP) content and in vitro organic matter digestibility (INVOMD) in rainy than in dry season (P<0.05), but Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) did not vary significantly with season (P>0.05). ADF and NDF were significantly higher in species from communal ngitili than those from private ngitili (P<0.05). Above-ground herbaceous biomass and bulk density (BD) were significantly higher in the rainy season and in the private ngitili than in the dry season and in the communal ngitili respectively. Cattle and goats spent considerably more time grazing and browsing respectively in the rainy season than in the dry season (P<0.05). Cattle foraging activities did not vary significantly (P>0.05) with ngitili management, but goats found to spend considerably more time browsing in the communal ngitili and more time grazing in the private ngitili (P<0.05). Despite the merits of stocking cattle and goats together in the heterogeneous pasture, seasonal variation in forage resources requires investigation of other strategies such as use of multipurpose trees and treatment of crop residues to improve livestock production.     

兰州地区苜蓿和红豆草根际溶磷菌筛选及菌株部分特性研究

利用溶磷圈法对苜蓿和红豆草根际不同部位溶磷细菌进行了分离,共获得分离物386个,其中137个具有溶磷能力.苜蓿和红豆草根际不同部位溶磷菌数量分布有差异.其数量为RS>RP>NRS>HP.对筛选获得的12株溶磷圈较大的菌株进行菌落形态特征观察发现,大多数菌落呈灰白色或乳白色、不规则、半透明、边缘不整齐、突起、无光泽、无色素.进一步利用钼蓝比色法对菌株分解磷矿粉能力测定显示,各菌株分解磷矿粉能力差异较大,溶磷量最大为338.4mg/ml,最小为25.9mg/ml,这与其自身溶磷机制有关.溶磷量与菌株培养液pH值之间存在显著相关性.12株菌株大部分具有分泌IAA的能力,其中LM6和LH9分泌IAA能力较强.     

精氨酸在畜禽营养生理中的应用进展

精氨酸在动物体内参不仅参与多种营养物质的合成分解代谢,同时通过精氨酸酶、一氧化氮两条代谢途径,参与机体内的免疫调节。由于断奶仔猪与哺乳母猪自身不能合成足量的精氨酸以满足代谢需要,因此需要从外源摄取以满足需求;另外,家禽体内也缺乏可以合成精氨酸的氨甲酰磷酸酶,其整个生长阶段更是需要补充外源性精氨酸。