丝兰属植物提取物降低鸡舍氨气浓度的研究

通过在21日龄的肉用仔鸡饲料中添加丝兰属植物提取物(其有效成分为丝兰皂角苷),研究丝兰属植物提取物对降低鸡舍中氨气浓度和提高肉仔鸡生产性能的效果。28d试验表明,试验组鸡舍内氨气平均浓度为4.75mg/L,对照组鸡舍内氨气平均浓度为13.80mg/L,试验组比对照组鸡舍内氨气平均浓度降低了9.05mg/L,经t检验,两鸡舍内氨气平均浓度差异显著(P<0.05),并且试验组比对照组饲料报酬提高了8.92%。     

脂肪酸提取方法对芽胞杆菌种类脂肪酸测定结果的影响

脂肪酸是细菌细胞膜的重要组成物质,受细胞膜上遗传物质的控制,具有灵敏度高、成分高度保守和含量稳定等特点,其碳链长度、双键位置和功能团组合的不同使其成为有效的分类标记。在细菌培养和脂肪酸提取阶段,芽胞杆菌属种类的脂肪酸鉴定结果受到皂化时间和脂肪酸提取试剂量的影响。本研究以球形芽胞杆菌为例,分析了皂化时间、皂化试剂量和甲基化试剂量对脂肪酸鉴定结果的影响。研究结果表明:皂化时间在25~30min的测定效果较好;皂化试剂量为1.0mL、甲基化试剂量为1.5mL时,球形芽胞杆菌的脂肪酸鉴定效果较好。     

一种快速提取番茄叶片DNA的方法

以番茄的幼叶为实验材料提取总DNA,经0.8%的琼脂糖凝胶电泳检测结果发现：DNA质量较好,所得的DNA可用于RAPD等技术。此法具有提取速度快、质量高和经济实用等优点。     

不同型号酵母浸粉及补糖对异养微藻生长的影响

微藻在FM802、FM902和FM760 3种不同型号的安琪酵母浸粉配制的培养基中进行异养生长,培养条件为28℃、200 r/min的摇床中进行暗培养,培养过程中补糖1次,每隔24 h取样20 mL进行分析检测。结果表明:补糖情况下,型号为FM802的酵母浸粉比FM902培养微藻的效果稍好,FM760培养效果稍差;补糖有利于微藻干物质重的增加;在pH值为4.2~5.5的培养基中,微藻仍能快速生长。     

樟科植物提取物对断奶仔猪粪尿氮排放的影响

为研究樟科植物提取作为脲酶抑制剂对仔猪粪尿氮排泄的影响,选取杜长大三元杂交30日龄断奶仔猪480头,按胎次、体重相近和公母基本一致分成5个处理组,分别饲喂添加不同剂量樟科植物提取物的日粮,即空白对照组Ⅰ、150 mg·kg-1组Ⅱ、300 mg·kg-1组Ⅲ、450 mg·kg-1组Ⅳ、600 mg·kg-1组Ⅴ,每个处理设3个重复,每个重复32头猪.结果表明:第Ⅳ、Ⅲ组与第Ⅰ组相比,料肉比分别降低5.67%(P＜0.01)和4.64%(P＜0.01);第Ⅳ、Ⅴ组与第Ⅰ组相比,粪样中微生物的脲酶活性显著降低(P＜0.05);第Ⅴ、Ⅳ组的尿素分解减少,总氮保持率提高,48 h后与第Ⅰ组差异均达到极显著水平(P＜0.01).樟科植物提取物的添加使血清中总蛋白含量提高、尿素氮含量降低.试验结果表明樟科植物提取物添加在断奶仔猪日粮中能够促进仔猪生长,抑制粪中脲酶活性,减少粪尿氮排泄,最佳使用剂量为450 mg·kg-1饲料(Ⅳ组).     

朱顶红叶片提取物抑菌效果的初步研究

为开发利用朱顶红提供依据,研究朱顶红叶片提取物对病原真菌的抑菌作用,以石油醚和丙酮为溶剂对朱顶红叶片中的活性物质进行索氏提取,并对其提取物进行了生物测定。结果表明,其活性物质对4种病原真菌菌丝生长都表现出抑制作用,0.06 g/mL以上浓度的抑菌效果明显。相同浓度下的孢子萌发试验结果显示:活性物质除了对枇杷叶斑病菌(Pes-tulotiopsis funerea)的抑制效果较差外,对其他3种病菌孢子的萌发抑制率均在73%以上。     

50种中草药提取物对猪链球菌的体外抑菌试验

对猪链球菌临床分离耐药株分别进行纸片扩散法和微量稀释法检测,通过对抗菌效果的比较,筛选出对耐药菌抗菌活性好的中草药,测定50种中草药的水提物和75%乙醇提取物对5株猪链球菌临床分离耐药株的体外抗菌活性。试验结果表明,50种中草药中,只有中药1和中药2的提取物对猪链球菌临床分离耐药株有较好的抑制作用,其他中草药对猪链球菌临床分离耐药株均无抑制作用。结果表明,中药1和中药2的75%乙醇提取物比水提取物抗菌活性强。     

桃叶卫矛假种皮浸提液对种子发芽的影响

用桃叶卫矛假种皮的浸提液对萝卜种子进行处理(2种溶剂,3个浓度梯度,即浸提液原液的10%,5%,2.5%)的结果表明,水浸提液处理的发芽率均为60%~70%;浓度为10%的乙醇浸提液处理的种子发芽率很低,甚至不发芽;浓度为2.5%的乙醇浸提液处理的种子发芽率也在40%以下;而乙醇处理的种子发芽率都在80%以上.因此,桃叶卫矛的假种皮浸提液对种子发芽有抑制作用.     

Influence of condensed tannin on intake, digestibility, and efficiency of protein utilization in beef steers fed high concentrate diet

This trial was conducted to evaluate if the effect of condensed tannin (CT) is associated with a true protein source on intake, ruminal and total digestibility, ruminal digestion rate, protein efficiency, and microbial efficiency in beef steers fed high concentrate diet (87% of DM). Four Bos indicus steers (407 ± 12 kg of BW) fitted with rumen cannula were assigned to a 4 × 4 Latin square design, arranged in a 2 × 2 factorial arrangement. Treatments consisted of either inclusion (0.4% of DM) or exclusion of condensed tannin (CT) from quebracho extract (76% of CT) with or without the use of soybean meal (SBM) as source of true protein. The level of inclusion was calculated to provide a daily intake of 1 g/10 kg of BW of CT. Intake of DM and nutrients was not affected (P > 0.10) by CT inclusion. However, there was an effect (P < 0.10) of CT inclusion on ether extract digestibility. An interaction (P < 0.10) was observed between CT and SBM on ruminal digestibility and digestion rate of crude protein (CP): when mixed with soybean meal, CT decreased the ruminal digestibility and, consequently, reduced the digestion rate of CP. Intake of CP increased (P < 0.10) with the inclusion of SBM. No differences in DM passage rate were observed (P > 0.10) among treatments. Effects of the interaction (P < 0.10) between CT and SBM were observed on flux of rumen undegradable protein (RUP), metabolizable protein (MP), and on the ratio MP:CP. In the presence of soybean meal, the addition of CT increased (P < 0.10) the flux of RUP and MP, and improved the ratio MP:CP. The yield of microbial protein on the abomasum and the microbial efficiency did not differ among treatments (P > 0.10). There was no difference (P > 0.10) on the pH, VFA, and ruminal ammonia (N-NH₃) with the addition of condensed tannin. The N-NH₃ increased and the ruminal pH decreased with the inclusion of soybean meal (P < 0.10). The utilization of condensed tannin as an additive in beef cattle diets with high level of concentrate and soybean meal as a source of true protein implies positive effects on crude protein utilization, decreasing digestion rate and ruminal digestibility of crude protein and consequently increasing the levels of metabolizable protein, with no changes in the ruminal fermentation parameters.     

狭叶菖蒲乙醇提取物对棉铃虫卵和幼虫的生物活性

为筛选安全高效的棉铃虫防治药剂,选用狭叶菖蒲Acorus calamus var.angustatus乙醇提取物对棉铃虫Helicoverpa armigera卵和幼虫的触杀活性、胃毒作用、拒食效果和生长抑制作用进行了测定,同时以0.5%藜芦碱为药剂对照,对比分析狭叶菖蒲提取物的杀虫效果。结果表明,狭叶菖蒲乙醇提取物对棉铃虫3龄幼虫有显著的触杀、胃毒、拒食和生长抑制活性以及杀卵效果,且生物活性随浓度升高和处理时间延长而增加;狭叶菖蒲提取物对棉铃虫触杀活性、胃毒活性、杀卵活性的致死中浓度LC_(50)分别为20.50、19.26和31.39 mg/m L,对棉铃虫生长抑制中浓度EC_(50)和拒食中浓度AFC_(50)分别为7.15、10.43 mg/m L;0.5%藜芦碱药剂对棉铃虫触杀活性、胃毒活性和杀卵活性LC_(50)分别为12.19、16.90和29.87 mg/m L,对棉铃虫EC_(50)和AFC_(50)分别为3.99、8.32 mg/m L,均低于菖蒲根茎提取物。气相色谱-质谱分析结果显示,狭叶菖蒲乙醇提取物主要成分为α-细辛醚、β-细辛醚、菖蒲酮和白千层醇。表明狭叶菖蒲乙醇提取物有开发为新型植物源农药的潜力。