乳酸杆菌和芽孢杆菌对产蛋鸡生产性能影响的研究

试验主要通过使用乳酸杆菌和芽孢杆菌的混合制剂饲喂产蛋鸡，测定鸡的生产性能及抗病能力。研究结果表明，饲喂蛋鸡后效果明显，不仅提高了蛋鸡的产蛋率、产蛋个数、蛋重和鸡饲料的转化率，还增强了鸡的抗病能力。     

试析如何合理选择造林树种

按造林目的,根据林种、立地条件合理选择造林树种从而提高造林效果的探讨和浅析。     

带叶休眠对休眠解除期间葡萄芽呼吸代谢的影响

 以中高需冷量葡萄品种‘夏黑’为试材,研究人工脱叶休眠处理和带叶休眠处理对休眠解除期间芽体呼吸代谢的影响。结果表明：与人工脱叶休眠处理相比,带叶休眠处理明显促进芽的休眠解除。带叶休眠处理与人工脱叶休眠处理芽在休眠解除期间的呼吸速率和途径变化趋势相似,但带叶休眠处理芽呼吸速率和途径发生显著变化的时间明显早于人工脱叶休眠处理,并且总呼吸速率和糖酵解—三羧酸循环途径、交替途径的运行活性和容量及剩余呼吸比例都高于人工脱叶处理。     

灵芝含量和发酵温度对灵芝葡萄酒质量的影响

灵芝葡萄酒含有多种营养物质和活性成分,具有保健和预防疾病的作用,但灵芝葡萄酒的质量受多种因素的影响。本试验以黑提葡萄和赤灵芝Ganoderma lucidum(Curtis,Fr.)P.Karst为材料,设置2个因素的不同水平处理:灵芝含量0、3.0 g·kg~(-1)、7.0 g·kg~(-1)、11.0 g·kg~(-1)和温度20℃、25℃、自然(18℃~34℃),通过测定pH、酒精度、残糖量、甲醇含量、总SO2含量、干物质含量、灵芝三萜含量、苦味等指标,研究其对灵芝葡萄酒质量的影响。结果显示,综合各项指标,对灵芝葡萄酒质量影响效果由好到差顺序的处理分别是灵芝含量:7.0 g·kg~(-1)11.0 g·kg~(-1)3.0 g·kg~(-1)0,温度:25℃20℃自然温度(18℃~34℃)。因此,灵芝葡萄酒制作的最佳条件为灵芝含量7.0 g·kg~(-1),发酵为温度25℃,本试验为酿造优质灵芝葡萄酒提供技术指导。     

开放教育中的英语报刊教学

开放教育中的报刊英语教学对提高学生综合语言能力起到很重要的作用。因此阅读理解报刊新闻英语的能力被视为成人教育中成功习得英语的必要手段之一。本文首先讨论成人学生在报刊英语学习中遇到的困难，然后指出教师在开展教学活动中面临的问题，在此基础上，作者结合教学实践，论述了尝试进行报刊英语教学的新方法。     

螺旋槽滚刀轴剖面齿顶斜角的分析论证—兼与吴能章,刘殿亭两先生…

本文针对某些文章在论述螺旋槽滚刀轴向齿顶斜角中的错误，阐明了齿顶斜角形成的原因及过程，推导出齿顶斜角的准确表达式，并对某些文章的疏失和错误进行分析讨论。     

Effects of Compound Bacteria Preparation on Fermentation Quality and Rumen Fermentation Characteristics of Phragmites australis Silage北大核心CSCD

The purpose of this study was to investigate the effects of compound bacteria preparation (including homogeneous Lactobacillus/heterogeneous Lactobacillus, Bacillus subtilis and Aspergillus niger as well as their compatibility) on nutrient composition, fermentation quality and rumen fermentation characteristics of Phragmites australis silage. Taking growing Phragmites australis from Dongting lake as silage material, five groups were set up, which were blank group (CK group), lactic acid bacteria group (LA group, supplemented with Lactobacillus plantarum, Pediococcus pentosaceus and Lactobacillus buchneri), lactic acid bacteria+Bacillus subtilis group (LA+BS group), lactic acid bacteria+Aspergillus niger group (LA+AN group) and lactic acid bacteria+Bacillus subtilis+Aspergillus niger group (LA+BS+AN group), and each group had 3 replicates. The supplemental level of lactic acid bacteria was 1.5×108 CFU/kg silage raw materials, and the supplemental levels of Aspergillus niger and Bacillus subtilis were 1.0×108 CFU/kg silage raw materials (all were based on fresh weight of silage raw materials). After 60 days of silage, the nutrient composition and fermentation quality of Phragmites australis silage were determined, and the rumen fermentation characteristics were evaluated by in vitro fermentation and in vivo degradation. The results showed as follows: 1) the contents of dry matter and ash in LA, LA+BS and LA+AN groups were significantly lower than those in CK group (P<0.05), and the crude protein content in LA+BS, LA+AN and LA+BS+AN groups was significantly higher than that in CK and LA groups (P<0.05). 2) The silage sensory evaluation scores of all groups were 60 to 70 points, and the ratings were good. The comprehensive scores of fermentation quality in LA+BS and LA+AN groups were higher, among which, the ammonia nitrogen to total nitrogen ratio, acetic acid content and acetic acid to total acid ratio in LA+AN group were significantly decreased compared with CK group (P<0.05), while the lactic acid content and lactic acid to total acid ratio were significantly increased compared with CK group (P<0.05). 3) The dry matter disappearance rate and total gas production of in vitro fermentation in LA+AN group were significantly higher than those in the other groups (P<0.05), and in vitro fermentation parameters such as volatile fatty acid contents in fermentation liquid were improved. 4) The rumen fermentation dry matter degradation rate in LA+AN and LA+BS+AN groups at 8, 24 and 48 h was significantly higher than that in the other three groups (P<0.05). In conclusion, the combined application of lactic acid bacteria and Aspergillus niger with supplemental levels in this experiment has the best effect on the quality of Phragmites australis silage and rumen fermentation characteristics. © The Author(s) 2023.     

蔬菜废弃物中温厌氧发酵酸化失稳预警指标筛选

厌氧消化是一种可以较好地将有机废弃物处理和能源回收结合的生物技术,它是多种厌氧微生物共同参与、分阶段有序进行的复杂串联代谢过程。其中产甲烷菌对环境最敏感、代谢速率最慢,产甲烷阶段往往是厌氧消化系统的瓶颈,水解酸化与产甲烷两阶段不能较好地匹配,极易受到抑制。针对蔬菜废弃物厌氧发酵易酸化的特点,该试验旨在筛选发酵体系酸化失稳预警指标,采用自行设计的70 L反应装置,在中温35℃条件下进行蔬菜废弃物厌氧发酵的连续冲击负荷试验。通过对发酵过程中的气相及液相指标监测,该研究筛选出4类失稳预警指标,分别为:1)甲烷与二氧化碳的比值。当CH_4/CO_21.06时,系统出现酸化现象,提前18 d对厌氧发酵系统做出预警指示,具有最强的失稳预警性;2)挥发性脂肪酸。当丙酸、正/异丁酸、正/异戊酸出现突变时,系统出现酸化征兆,分别在17、15和15 d对厌氧消化体系做出失稳预警;3)碱度。包括总碱度(total alkalinity,TA)、碳酸氢盐碱度(bicarbonate alkalinity,BA)、及挥发酸盐碱度(intermediate alkalinity,IA)的耦合性指标,当BA1500 mg/L、BA/TA0.8或IA/BA0.4时,系统提前13、12和12 d做出酸化预警指示,此时发酵体系缓冲性能较差,系统极易出现挥发性脂肪酸的累积进而导致系统酸化失稳;4)氧化还原电位和pH值在整个厌氧消化过程中均持续微弱变化,利用其绝对值很难做出失稳判断,利用其相对变化值可做出失稳判断,骤变分别发生在产气彻底停止前第5天和第4天,预警能力较弱。在工程实际应用中,相比液相指标而言,气相指标的监测更容易实现,建议CH_4/CO_2作为预警指标。