Rumen Function and Development     

《Veterinary Clinics of North America: Food Animal Practice》2017,33(3):427-439

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饲粮中添加木聚糖酶对肉鸡生产性能的影响     

王福勇 《草业与畜牧》2012,(5)

本试验采用2×2因子试验设计，在两种能量水平饲粮中分别添加或不添加木聚糖酶饲养艾维菌肉公鸡，旨在研究木聚糖酶在肉鸡不同能量饲料中的应用效果。每个处理6个重复，每个重复20只。试验结果为：降低饲粮能量水平可以降低肉鸡前期（0—3周）、后期（4—6周）或全期日增重、采食量趋势，显著降低后期或全期的饲料转化效率；添加木聚糖酶可显著提高后期或全期的采食量、各阶段肉鸡的日增重和饲料利用率；饲粮能量和木聚糖酶对肉鸡生产性能无显著的交互作用。结果表明：在试验的两种饲粮能量水平下，添加木聚糖酶均可改善肉鸡生产性能；在低能粮中添加木聚糖酶的效果更好，并可达到高能饲粮的效果。  相似文献   

外生菌根真菌纯培养中生理活性物质代谢的研究   总被引：2，自引：0，他引：2  

赵志鹏  郭秀珍 《林业科学》1990,26(5):465-469

随着外生菌根研究的不断深入,越来越多的菌根工作者开始注意到了外生菌根真菌生理活性物质研究的重要价值。T.Santoro et al.,G.N.Krywolap et al.,D.H Marx等先后研究了外生菌根菌在各种培养条件下产生拮抗活性物质及这些拮抗物的理化性质和生物学功能,证明了外生菌根具有生物防治效应的部分原因是由于真菌抗生素的分泌。80年代以来,发现外生菌根及其真菌产生的植物激素在形成菌根及促进寄主植物生长方面起重要作用。如J.H.Graham et al.等先后研究了外生菌根菌产生某些  相似文献   

Pregnancy impairs ketone body disposal in late gestating ewes: implications for onset of pregnancy toxaemia     

Harmeyer J  Schlumbohm C 《Research in veterinary science》2006,81(2):254-264

The impact of pregnancy on ketone body disposal during a hyperketonaemic clamp was examined by tracer isotope dilution techniques in seven 12 h fasted sheep in three reproductive states, in the dry non-gestating period, late in gestation and during early lactation. After a sampling period of 60 min under basal conditions a DL-BHB racemate solution was continuously infused intravenously for 3 h at rates of 14.3-24.3 micromol/(kg min) to elevate the D-BHB concentration in blood plasma to values between 5 and 7 mmol/l. Two separate experiments were carried out with the same sheep in each of the three reproductive states. During pregnancy three ewes were pregnant with a single lamb and four ewes carried twins. Maximal D-BHB turnover rates fell significantly in late gestation by 26% relative to early lactation and by 22% when compared with the dry non-pregnant state. Reduction of maximal D-BHB disposal rate during late gestation was accompanied by a significant 297% (p<0.005) and a non-significant 49% increase in the basal BHB concentration in blood, a non-significant 10% and 4% decrease in the rate constant of D-BHB turnover and a non-significant 24% and 13% rise in the incremented increase of D-BHB concentration per unit D-BHB infusion, relative to the dry and the lactating period, respectively. Induction of hyperketonaemia significantly lowered NEFA and glycerol concentrations in blood by 67% and 57%, respectively, compared to the pre-infusional concentrations. The magnitude of this effect was the same in all reproductive states and was explained as a direct antilipolytic action of D-BHB on adipose tissue. It is concluded that the reduced ability of the late gestating ewe to utilize D-BHB promotes hyperketonaemia. Since hyperketonaemia exerts several adverse effects, e.g. on energy balance and glucose metabolism it appears that the impairment of ketone bodies disposal in late pregnancy facilitates development of pregnancy toxaemia, especially in ewes carrying twins.  相似文献   

不同催青处理的二化性家蚕体内过氧化氢代谢   总被引：1，自引：0，他引：1  

赵林川  时连根 《蚕业科学》2006,32(1):52-57

研究了25℃明催青和15℃暗催青对二化性家蚕品种丰一体内的H2O2代谢影响。在催青期,前一种处理的蚕卵体内H2O2代谢水平在中后期呈U型变化,过氧化氢酶(CAT)活性在后期迅速上升;后一种处理的蚕卵体内H2O2代谢水平在第16天出现峰值,CAT活性在后期缓慢上升。在幼虫期,两种催青处理的H2O2代谢基本相似,均是H2O2代谢水平随龄期增加而逐步下降,CAT活性在1~4龄逐步下降,而在5龄期有所回升。在蛹期,前一种处理的H2O2代谢水平分别在第2天和第9天出现峰值,CAT活性分别在第3天和第6天出现峰值;后一种处理的H2O2代谢水平在第4天出现峰值,CAT活性在第5天出现峰值。上述结果表明,不同催青条件显著改变了家蚕催青期和蛹期的H2O2代谢,滞育诱导阶段的家蚕H2O2代谢可能与滞育激素(DH)的表达密切相关。  相似文献   

低温和镁胁迫对黄瓜幼苗生长和生理特性的影响     

谢小玉  张喆 《中国蔬菜》2012,1(22):54-58

利用人工气候箱,采用珍珠岩培养,研究不同温度下镁对黄瓜幼苗生长、碳氮代谢和活性氧清除系统的影响。结果表明,低温下,镁胁迫降低了黄瓜的总叶片数、叶面积、根长、全株干质量和壮苗指数,增大了根冠比。适温下,镁胁迫使黄瓜叶片可溶性蛋白、还原糖和可溶性总糖含量、硝酸还原酶活性下降,根系活力提高;低温下,各处理硝酸还原酶活性、根系活力、可溶性总糖含量较对照降低,还原糖含量较对照升高,多镁和适镁使可溶性蛋白的含量较对照降低,缺镁则使其含量较对照提高。多镁和缺镁均导致黄瓜幼苗叶片MDA、H2O2含量及O2 产生速率升高,缺镁升幅大于多镁。低温缺镁对植株的伤害最大,可能与活性氧的增加有关。适温下,镁胁迫使POD、SOD活性升高,其中POD活性升高幅度最大,而CAT活性降低;适温下植株可能主要通过提高POD活性来抵御镁胁迫。  相似文献   

多胺代谢与植物抗逆性研究进展   总被引：2，自引：0，他引：2  

宋永骏  刁倩楠  齐红岩 《中国蔬菜》2012,1(18):36-42

多胺是广泛存在于植物体内具有调控作用的一类生理活性物质,其代谢变化与高等植物的生长、发育和抗逆性关系密切。本文从逆境胁迫下多胺代谢情况、外源多胺及其抑制剂对植物抗逆性的影响、突变体与转基因在研究多胺与抗逆性上的应用三个方面对多胺与逆境之间的关系进行介绍,并对逆境下多胺如何影响其他生理活动（作为渗透调节物质,信号分子,调节离子通道）进行了系统性地阐述,最后对其研究前景进行了展望。  相似文献   

四合木水分代谢特性的初步研究   总被引：3，自引：0，他引：3  

刘果厚  周世权  张力  蔺福金  任林 《干旱区资源与环境》1993,(2)

四合木(Tetraena mongolica Maxim)为内蒙古特有的国家二级保护、内蒙古一级保护植物。本文首次报道了四合木的水分状况(总含水量、自由水含水量及束缚水含水量)和水分代谢(水势、蒸腾速率及抗脱水力),并且讨论了这些特性与忍受干旱的关系,为进一步保护这种植物提供科学依据。  相似文献   

Absorption, translocation, and metabolism of propoxycarbazone-sodium in ALS-inhibitor resistant Bromus tectorum biotypes     

Kee Woong Park 《Pesticide biochemistry and physiology》2004,79(1):18-24

Experiments were conducted to investigate the absorption, translocation, and metabolism of propoxycarbazone-sodium in acetolactate synthase-inhibitor resistant (AR and MR) and susceptible (AS and MS) Bromus tectorum biotypes. Absorption and translocation of ^l4C-propoxycarbazone-sodium were similar in all biotypes. One major and three minor metabolites were identified using reverse-phase high performance liquid chromatography. In all biotypes, 80% of the propoxycarbazone-sodium was metabolized by 72 h after treatment (HAT). However, propoxycarbazone-sodium was metabolized more rapidly in the MR biotype than in the other biotypes. The half-life of propoxycarbazone-sodium in the MR biotype was 8.9 h, which was 30, 36, and 40% shorter than in the AS, AR, and MS biotypes, respectively. When ¹⁴C-propoxycarbazone-sodium was applied with 1-aminobenzotriazole, a known cytochrome P450 inhibitor, metabolism decreased 20% 12 HAT in the MR biotype. These results indicate that resistance of the MR biotype to propoxycarbazone-sodium is due to a relatively rapid rate of propoxycarbazone-sodium metabolism compared to other B. tectorum biotypes and that cytochrome P450s may be involved in the metabolism. The fact that these populations evolved so quickly and with different resistance mechanisms is a concern as more ALS inhibitors are introduced into the production systems.  相似文献   

Carbaryl induced alterations in the reproduction and metabolism of freshwater snail Lymnaea acuminata     

Pankaj Kumar Tripathi 《Pesticide biochemistry and physiology》2004,79(1):1-9

When the freshwater snail Lymnaea acuminata was exposed to sub-lethal doses (2.0, 5.0, and 8.0 mg/L) of carbaryl, fecundity was significantly reduced and even stopped at higher sub-lethal doses and altered metabolic activity in the body tissue of the snail was observed. The change from aerobic to anaerobic metabolism results in lesser energy production in the body tissues of the snails, causing paralysis and finally death. This reduced fecundity and altered metabolism suggests that it would be better to avoid the use of carbaryl pesticides in the water bodies or fields adjoining the water bodies particularly in the rainy season.  相似文献