不同山羊草细胞质效应的比较研究

以 2 4种不同山羊草细胞质的稳定同核异质杂种为材料 ,进行了植株生长特性、病害抗性、抗低温能力、光合特性、主要农艺性状、自交育性和种子蛋白质含量等方面的比较研究。同时 ,还分析了异源细胞质效应的遗传特点 ,指出了生产上有应用价值的细胞质材料     

珍珠粟在畜禽饲料中的应用研究进展

珍珠粟作为一种重要的热带谷类作物而广泛地种植于半干旱地区,坑旱、耐瘠,其籽实蛋白质含量高,氨基酸组成合理,含抗营养因子少,作为玉米的替代品而广泛地应用于畜禽养殖业中,尤其在非反刍动物饲料中的应用效果较好。     

Effects of feeding diets containing low crude protein and coarse wheat bran as alternatives to zinc oxide in nursery pig diets

Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.     

三峡库区灌丛群落多样性的研究

通过对三峡库区灌丛群落的初步调查,该地区灌丛现有１５个群落类型,常见的球核荚灌丛,白栎灌丛,黄栌灌丛,其丰富度指数、多样性指数相对较高,而疏水柏枝灌丛、秋华柳灌丛物种相对单一,灌丛群落多样性在海拔梯度上未表现出明显的规律性,这可能与库区强烈的人为干扰活动有关。     

Isolation of Salmonella Organisms from Commercial Layer Houses Where the Flocks Were Molted with a Wheat Bran Diet

To develop an alternative method to feed withdrawal for molting layers, 2 flocks consisting of approximately 26,000 commercial laying hens each at 478 (68 wk, flock 1) and 466 (67 wk, flock 2) d of age were reared in an environmentally controlled windowless house and were fed wheat bran (WB) diet. Flock 1 hens were fed WB for 25 d, and flock 2 hens were fed WB for 21 d and then fed a mixture of WB and layer feed (1:1, wt:wt) for the last 4 d of the treatment. After that, the birds in both flocks were fed a normal layer feed. The photoperiod was reduced from 16 to 9 h in both flocks. Most of the birds in both flocks ceased egg production by 10 to 15 d of feeding the WB diets. Egg production in flock 1 gradually increased to 11.4% by 31 to 40 d and 71.4% by 41 to 50 d of the treatment, whereas the egg production in flock 2 hens lagged behind by almost 10 d. The mean egg production from 61 to 140 d exceeded 86% in both flocks. The houses in the farm were naturally contaminated with several serovars of Salmonella, not Enteriditis or Typhimurium. In both flocks with the WB treatment, no marked increase in Salmonella isolation from environmental samples was observed postmolt relative to premolt levels. The study demonstrated that feeding hens WB could be successfully used as an alternative to feed withdrawal to force-rest aging hens while not exacerbating a Salmonella problem in a commercial egg-production setting.     

拉萨河谷山地灌丛草地植物多样性监测方法的比较研究

生物多样性是西藏生态安全监测与评估的重要内容之一.在气候变暖和放牧干扰背景下沿海拔梯度探讨西藏拉萨河谷山地灌丛草地植物群落物种多样性的变化特征,对于该地区草地的保护与可持续利用具有重要意义.以拉萨市林周县白朗村沟域的山地灌丛草地为研究对象,采用常规样方法,重复样线法和Modified-Whittaker样地法3种方法进行系统调查,研究草地群落物种组成及其沿海拔梯度的变化特征.结果表明,1) 3种不同取样方法α多样性的物种丰富度均随海拔的升高呈先增加后降低的趋势,其中50 m样线法效果最好.2) 表征β多样性的Sorensen相似性指数和Bray-Curtis指数均随样地间海拔高差的增大而减小.3) 种-面积关系的截距c,斜率z随海拔的升高呈先增加后降低的趋势,与α,β多样性随海拔梯度的变化特征吻合一致.4) 依据种-面积关系研究结果,山地灌丛草地设置100 m²的样地可覆盖80%左右的植物物种.山地灌丛草地的α和β多样性指数沿海拔梯度均呈先增后减的变化特征,未来研究应注重植物多样性分布格局对山体气候梯度以及放牧干扰变化的响应和适应机制.     

放牧对青海湖北岸高寒草原植物群落特征的影响

基于青海湖北岸高寒草原连续3年放牧控制试验,研究了暖季和冷季放牧草地植物群落特征的变化。结果表明,暖季和冷季放牧草地群落地上生物量均随放牧强度的增加呈现下降趋势,禾本科地上生物量的变化趋势基本与群落地上生物量的一致;中度放牧对暖季放牧草地植被的影响程度高于冷季放牧草地;围栏封育区和冷季重度放牧草地的优势种均为紫花针茅(Stipapurpurea)和矮嵩草(Kobresia humilis),暖季放牧各放牧小区和冷季放牧草地轻度和中度放牧处理优势种均为紫花针茅和披针叶黄华(Thermopsis lanceolata);随放牧强度的增加,暖季放牧草地群落物种多样性指数和均匀度指数表现出先降低后增加的趋势,冷季放牧草地群落物种多样性指数和均匀度指数表现出增加的趋势,但是多样性指数在暖、冷季放牧草地均以重度放牧区最高。     

乌桕金带蛾新种记述(鳞翅目:带蛾科)

本文为贵州省的重要林木害虫－乌桕金带蛾的新种记述，与近缘种中华金带蛾详加比较，附有特征图以兹鉴别。     

不同方法处理对4种野生草种发芽率的影响

试验采用了酸、碱、有机试剂、植物激素、热水浸泡、超声波以及擦破种皮等11种方法对4种野生草种进行处理。结果表明:所有方法处理对马唐的种子萌发均没有显著影响(P0.05);野豌豆种子在擦破种皮处理下,发芽率从1.11%提高到96.67%,达到极显著水平(P0.01),其他处理对野豌豆种子发芽率均无明显影响(P0.05);香附子和稗草种子在20%NaOH的方法处理下,发芽率分别从10%和2.22%提高到86.67%和58.33%,均达到极显著水平(P0.01);此外,1 000mg/L赤霉素浸种处理也可极显著提高香附子种子的发芽率(P0.01)。其他方法处理对香附子和稗草种子发芽率均无明显影响(P0.05)。不同野生草种的休眠特性不同,试验选用的马唐种子无休眠性;野豌豆种子需物理破皮;20%的NaOH和1 000mg/L赤霉素处理可打破香附子种子休眠;20%的NaOH处理能打破稗草种子休眠。     

贵州黑马羊的选育

试验采取在农家组建核心群、基础群的开放式选育路线,制订初步淘汰标准、综合选择指数,指导整群淘汰、选种选配。结果发现,选育后核心群周岁公母羊体重分别为29.77 kg±5.51 kg、25.18 kg±5.67 kg,成年公母羊体重分别为40.08kg±7.73 kg3、4.90 kg±6.56 kg;选育后基础群周岁公母羊体重分别为26.59 kg±3.68 kg、24.09 kg±4.60 kg,成年公母羊体重分别为35.33 kg±4.09 kg3、2.16 kg±6.83 kg;产羔率达152.33%。经t检验,选育后核心群周岁公母羊、基础群周岁公母羊、成年公母羊平均体重极显著高于选育前的平均体重(P0.01)。无角对有角是显性,山羊间性与无角存在连锁关系。