石粉粒度对蛋鸡生产性能、钙表观存留率及胫骨钙含量的影响

选用６１周龄种禽褐壳蛋鸡２０８只，随机分为１３个处理，分别饲喂１３种不同粒度石粉构成的试验日粮（３，４％Ｃａ），测定钙表观存留率，结果表明：不同粒度石粉对蛋鸡钙表观存留率无显著影响（Ｐ＞０．０５）．另选用５４周龄种禽褐壳蛋鸡６２４只，随机分为１３个处理，分别饲喂１３种不同粒度石粉构成的试验日粮（３．４％Ｃａ）．结果表明：①不同粒度石粉对蛋鸡产蛋量、采食量、料蛋比等生产性能均无显著影响（Ｐ＞０．０５），但不同粒度石粉对破软蛋率有极显著影响（Ｐ＜０．０１），其中以添加７５％６～８目、１２．５％１０～１２目与１２．５％５０目石粉组和７５％８～１０目、１２．５％１０～１２目与１２．５％５０目两组破软蛋率最低；而小粒度石粉组即１００％５０目，２５％１０～１２目与７５％５０目两组破软蛋率最高，②不同粒度石粉对蛋鸡胫骨灰分及钙含量有极显著影响（Ｐ＜０．０１），其中以７５％６～８目、１２．５％１０～１２目与１２．５％５０目组和７５％８～１０目、１２．５％１０～１２目与１２．５％５０目石粉两组胫骨灰分及胫骨钙含量表现出显著优势（Ｐ＜０．０１），而１００％５０目及５０％１０～１２目与５０％５０目两组，胫骨灰分及钙含量最低。     

微量元素锰在蛋鸡养殖生产中的应用研究

锰缺乏或过量会引起代谢紊乱等疾病,给蛋鸡养殖业造成困扰和巨大的经济损失,因此在蛋鸡生产中越来越受到重视。作者主要介绍微量元素锰的生物学功能及其在蛋鸡养殖生产中的应用,阐述蛋鸡锰缺乏和中毒病的发病原因、临床特征及防治措施,为广大兽医工作者和养殖户提供参考。     

Crop yield and soil water restoration on 9-year-old alfalfa pasture in the semiarid Loess Plateau of China

The alfalfa pastureland in the semiarid Loess Plateau region of Northwest China usually has dry soil layers. A field experiment was conducted from October 2000 to October 2004 to examine soil water recovery and crop productivity on a 9-year-old alfalfa pasture. This experiment included six treatments: alfalfa pasture for 10-14 years, a conventional farming system without prior alfalfa planting, and four alfalfa-crop rotation treatments. For the rotation treatments, after 9 years of alfalfa selected crops were planted from 2001 to 2004 in the following sequence: (1) millet, spring wheat, potatoes, peas; (2) millet, corn, corn, spring wheat; (3) millet, potatoes, spring wheat, corn; (4) millet, fallow, peas, potatoes. The results showed that dry soil layers occurred in alfalfa pasture. We then plowed the alfalfa pasture and planted different crops. The soil water gradually increased during crop growth in the experimental period. The degree of soil water recovery in the four alfalfa-crop rotation treatments was derived from comparison with the soil water in the conventional system. After 4 years, the soil water recovery from the alfalfa-crop rotation systems at 0-500 cm soil depth was 90.5%, 89.8%, 92.2% and 96.7%, respectively. Soil total N content and soil respiration rate were high in the alfalfa-crop rotation systems. The yields of spring wheat in 2002, peas in 2003 and potatoes in 2004 in the alfalfa-crop rotation systems were not significantly different from yields in the conventional system. In the alfalfa-crop rotation systems, the yields of spring wheat and peas were greatly influenced by rainfall and were lowest in the dry year of 2004; the yields of corn and potatoes had a direct relationship with water use and were lowest in 2003. In summary, soil water in dry soil layers can recover, and crop yields in the alfalfa-crop systems were equal to those of the conventional system.     

动物单室胃肌层分层剥离解剖方法

运用大体解剖方法对兔、狗和猪等动物的单室胃肌层进行剥离,首先,分别用充盈固定法和无张力固定法固定标本;然后,分别将浆膜、粘膜和粘膜下层剥去,获得完整的胃肌层标本;最后,将胃肌层逐层整片剥离.剥离外纵行肌层时,从外表面观察外纵行肌层和环行肌层的分布特征;剥离内斜行肌层时,从内表面观察内斜行肌层和环行肌层的分布特征.解剖时遵循由厚到薄,由集中到分散,顺肌纤维方向剥离的原则.利用此方法观察发现,胃肌层分布范围不均衡,胃的不同部位肌肉配布厚薄不一,各层之间的连接疏密不均,初步建立了单室胃动物胃的肌层解剖方法和程序.     

不同日龄海兰鸡心率·血压及呼吸频率的研究

[目的]测定不同日龄海兰鸡心率、血压及呼吸频率,以丰富海兰鸡群的基础数据库。[方法]通过肢体导联的心电描记,从而测定出心率;血压采用直接测压法;呼吸频率按1min腹部羽毛起伏的次数计数。[结果]在11组中,小年龄段海兰鸡心率与其他鸡心率接近,但高于大年龄段的心率值;呼吸频率测定结果140、280和420日龄组与其他组差异极显著;6组海兰鸡收缩压与舒张压都是随着年龄的增长而升高,28与420日龄组差异极显著。[结论]实验测得的海兰鸡心率、血压和呼吸频率值都是随着日龄的变化,而在各组之间表现为差异显著性的。     

亚麻籽木脂素对产蛋鸡生产性能和脂类代谢的影响

研究木脂素对蛋鸡生产性能及脂类代谢的影响,结果表明：添喂木酯素的蛋鸡较饲喂日粮产蛋率提高,料蛋比下降,但无显著差异;血清总胆固醇含量对照下降27．71％（P〈0．01）,甘油三酯降低33．16％（P〈0．05）,游离脂肪酸降低33．24％（P〈0．05）;木脂素显著降低血清T,和FT3而显著升高雌二醇水平;木脂素有降低蛋黄中胆固醇的趋势。     

黑钙土不同土层在两种材质负压渗水器下的吸渗特性

基于–5 k Pa负压灌水条件下的一维垂直水分吸渗试验,分析了陶土和聚乙烯醇缩甲醛泡沫塑料(PVFM)两种材质负压渗水器在黑钙土A、B层的渗水性能,测定累计吸渗量、吸渗率、湿润峰及土壤含水率等指标,并利用它们考察了Kostiakov,Horton、Philip 3种常用的土壤水分吸渗模型及垂直一维非饱和土壤水分运动代数模式描述负压吸渗过程的适用性,进一步比较了不同处理下的模型参数。结果表明:(1)–5 k Pa灌水条件下,PVFM渗水器和陶土渗水器的累计吸渗量没有明显差异,前者能有效替代后者作为负压渗水器;(2)黑钙土B层土壤水分吸渗特性比A层差,同时间内累计吸渗量较少,吸渗率降低速度更快;(3)短时间负压灌溉条件下,不同土层的累计吸渗量与湿润峰、吸渗率与湿润峰倒数、湿润峰平方与时间均存在明显的线性关系;(4)负压灌溉后距离渗水器上下各15 cm范围内,土壤含水率维持于20%~33%范围内,变异系数均在10%左右;(5)拟合结果表明,Kostiakov与Philip模型能很好地描述–5 k Pa负压灌溉下不同处理的水分吸渗特性,而Horton模型描述黑钙土A、B层较长时间的吸渗效果较差。     

异黄酮对蛋鸡生产性能和脂类代谢的影响

选择400羽40周龄伊莎产蛋鸡来研究大豆黄酮、伊普异黄酮和染料木素3种异黄酮对蛋鸡生产性能以及脂类代谢的影响。试验随机分为4个处理,对照组饲喂基础日粮,3个试验组日粮分别添加6 mg/kg的大豆黄酮、伊普异黄酮和染料木素,试验为6周。结果表明:(1)大豆黄酮组产蛋率显著提高5.1%(P<0.05),料蛋比下降6.3%(P<0.05),其余2组有改善趋势;(2)大豆黄酮显著降低血清总胆固醇、甘油三酯、游离脂肪酸含量,分别较对照组降低27.97%(P<0.01)、43.41%(P<0.05)、44.96%(P<0.01);染料木素显著降低血清总胆固醇和甘油三酯,降幅分别为24.80%(P<0.05)、33.72%(P<0.05);(3)大豆黄酮显著降低血清T3和FT3,显著升高血清T4、FT4和雌二醇水平,伊普异黄酮显著升高血清T4水平;(4)大豆黄酮有降低蛋黄中总胆固醇的趋势。     

日粮中不同牛磺酸水平对蛋鸡体内脂类代谢的影响

将504只59周龄海兰褐蛋鸡随机分为7组,每组3个重复,每个重复24只鸡。在各组鸡饲粮中分别添加0%、0.005%、0.01%、0.02%、0.04%、0.08%、0.16%的牛磺酸,研究牛磺酸对蛋鸡血清、肝脏及蛋黄脂类代谢的影响。试验结果表明:1)日粮中添加牛磺酸能够显著降低68周龄蛋鸡血清总胆固醇、甘油三酯含量(P<0.05);显著提高64周龄及68周龄蛋鸡血清高密度脂蛋白胆固醇含量(P<0.05)。2)添加牛磺酸可显著降低68周龄蛋鸡肝脏胆固醇含量(P<0.05)。3)日粮中添加牛磺酸可降低68周龄蛋鸡蛋黄胆固醇含量但差异不显著(P>0.05);显著降低68周龄末产蛋鸡蛋黄中棕榈酸及硬脂酸含量(P<0.05);显著增加蛋黄油酸含量(P<0.05);极显著增加蛋黄亚油酸含量(P<0.01)。说明蛋鸡日粮中添加牛磺酸可以改善蛋黄脂肪组成。4)综合本试验各项结果,以添加0.005%水平牛磺酸调节蛋鸡脂类代谢的效果最佳。     

Determinants of stem form: Application to Tectona grandis (Linn. F) stands

ABSTRACT

Stem form information can enhance rapid estimation of stem volume. Studies on important determinants of stem form in pure stands are scanty. This study aimed at identifying determinants of stem form using Tectona grandis stands in Omo Forest Reserve, Nigeria. Twenty 0.04 ha square plots were randomly selected across four stand ages. Crown diameter, total and merchantable heights (MH), diameters at breast height (DBH), at 5.27 m tree height and at midpoint from breast height to tip of tree were measured in each plot. Measured trees were classified into four canopy layers (CL)—dominant, codominant, intermediate, and suppressed. Merchantable volume, basal area (BA), form factor (F_f), normal form quotient (Q_n), Girard form class (Q_G), absolute form quotient (Q_a), ratio of diameter at merchantable limit to diameter at the base (D_t/D_b), and tree slenderness coefficient were derived from the data. Analysis of variance, correlation, and regression analyses were used to analyze the data. Significant differences were observed in stem form and tree size variables under different canopy layers. The DBH, BA, MHT, and CL were identified as important variables associated with stem form. Inclusion of Q_a improved most the predictive ability of the selected stem volume equation.