全株玉米青贮及构树青贮饲料对肉牛增质量效果的影响

选择60头13～16月龄、体质量在400 kg左右(±15%)西杂肉牛为试验对象,随机分为3组,分别为玉米全株青贮组、构树青贮组和玉米秸黄干贮组(对照),在基础日粮(精料)、饲养管理水平完全相同的条件下,研究全株玉米青贮及构树青贮饲料对肉牛增质量效果的影响。结果表明,30 d饲喂后,全株玉米青贮饲料组和构树青贮组(各20头肉牛)的总增质量分别为1 092.6,992.4 kg,分别比黄干贮组20头肉牛总增质量多249,148.8 kg,差异显著;而全株玉米青贮饲料和构树青贮2组相比,虽然全株玉米青贮饲料组的增质量优于构树青贮组,但差异不显著。全株玉米青贮组增质量耗草耗料比分别为1∶6.48和1∶3.22,构树青贮组增质量耗草耗料比分别为1∶7.07和1∶3.54,玉米秸黄干贮组增质量耗草耗料比分别为1∶8.11和1∶4.16。全株玉米青贮组、构树青贮组和玉米秸黄干贮组(各20头肉牛)的总收入分别为24 037.2,21 832.8,18 559.2元,扣除总成本后的纯收入分别为11 495.2,10 179.8,7 085.2元;全株玉米青贮比构树青贮组多增收1 315.4元,比黄干贮组多增收4 410元。综合增质量耗草耗料比及经济效益分析,全株玉米青贮饲料组优于构树青贮组和黄干贮组,构树青贮组优于黄干贮组。     

景电灌区玉米增株减穴高产栽培新技术探讨

在介绍景电灌区玉米增株减穴高产栽培技术模式应用范围的基础上,总结其关键技术,包括品种要求、模式规格选择、合理施肥、病虫害防治等方面内容,并分析其技术效果,以期为玉米种植者提供参考。     

盆栽一株多果技术

一株多果技术是一种嫁接技术的新应用,通过嫁接手段把颜色或者形状等外形差别较大的同科属植物嫁接到同一植株上,以达到更好的观赏效果。对不同品种茄子嫁接的操作规程做简要概述,通过该技术在茄子嫁接上的演示,拓展人们思路,以便于今后更多种嫁接技术的创新。     

燕麦和全株玉米不同配比对TMR发酵品质及有氧稳定性的影响

文章旨在探究全株燕麦和全株玉米的不同配合比例对TMR发酵品质及有氧稳定性的影响。将新鲜全株燕麦和/或全株玉米与玉米粉、豆粕、豆腐渣、苜蓿干草、麸皮、维生素-矿物质预混料、食盐,按照干物质30:34.5:10.5:10.5:10:3:1:0.5的比例混合调制TMR,其中,全株鲜燕麦和全株玉米的比例分别为0:30、10:20、20:10和30:0。分别于厌氧发酵后7、14、28 d和56 d开封,测定发酵品质、微生物组成、化学成分以及发酵56 d的TMR有氧稳定性。结果表明,所有处理组的TMR均发酵良好,具有较高的乳酸含量、较低的p H值和氨态氮含量,并具有良好的有氧稳定性。随着发酵时间的延长,p H值和乙酸含量显著降低、乳酸含量极显著升高(P<0.01);干物质(DM)、中性洗涤纤维(NDF)和可溶性碳水化合物(WSC)含量极显著降低(P<0.01)。随着全株燕麦配合比例的增加,DM、CP、NDF和酸性洗涤纤维(ADF)含量极显著升高(P<0.01),WSC含量极显著降低(P<0.01);p H值和乳酸含量极显著增加(P<0.01)。全株燕麦调制的TMR均发酵良好,但有氧稳定性随着全株燕麦比例的增加显著降低。     

Construction and Partial Biological Characteristics Analysis of Listeriolysin S llsB Gene Deletion Strain

In order to analyze the effect of listeriolysin S (LLS) llsB gene deletion on the biological characteristics of Listeria monocytogenes (LM),this study used homologous recombination to construct the llsB gene deletion strain LM90-ΔllsB,and the biological characteristics of growth characteristics,median lethal dose (LD₅₀) and organ-borne bacteria were studied in healthy Kunming male mice at 8 weeks old and weighing 40 g±5 g.The llsB gene deletion strain was successfully constructed,and the deletion strain had good genetic stability through continuous passage to 20 generations in vitro.Based on its growth curve examination,we found that the growth rate of the mutant strain was slightly higher than that of the parent strain.The results of mice infection test showed that the LD₅₀ of the parent strain and the deletion strain were 10^6.17 and 10^6.50 CFU,respectively.Compared with the parent strain,the amount of bacteria load of the deletion strain in the liver and spleen of the mice was extremely significantly decreased (P<0.01),the results showed that the infection ability of the mutant strain on mice was obviously weakened.No Listeria monocytogenes was detected in the brain.The results suggested that llsB gene might have direct or indirect regulatory effect on some biological characteristics of LM90,and it would provide a theoretical basis for further understanding of the pathogenic mechanism of LLS,prevention and control of listeriosis.     

植物根际促生菌(PGPR)对非宿主植物猫尾草和小黑麦生长的促生作用

为了探究根际促生菌(PGPR)对非宿主植物[猫尾草(Uraria crinita)、小黑麦(×Triticale Wittmack)]生长的影响,本研究采用甘肃农业大学草业学院微生物实验室提供的10株具有固氮、溶磷、分泌激素和生防特性的PGPR菌株为供试菌株,筛选最佳菌种组合,并按一定比例混合制作微生物复合菌肥,在盆栽条件下,研究菌肥对非宿主植物小黑麦、猫尾草生长的影响。结果表明:1)通过试验筛选出的最佳菌种组合为NCRP2+PPRS3+G+ZKRP2;2)宿主植物菌肥(NF_1)处理对小黑麦地上生物量鲜重影响显著(P0.05),施用非宿主植物菌肥(NF_2)后与施用NF_1相比,猫尾草茎粗增加33.74%,且差异显著(P0.05);3)NF_2处理影响小黑麦根平均直径、根体积,与对照相比分别增加22.54%和125%,差异显著(P0.05),NF2处理对根直径0.5~1.0和1.0~1.5 mm小黑麦根长影响显著(P0.05)。PGPR菌肥对非宿主植物猫尾草和小黑麦生长具有明显的促生效果。