象草（Pennistum Purpurem Sch.）和甜高粱（sorghum bicolor）是重要的禾本科植物,廣泛種植于熱帶和亞熱帶地區(qū),常用于調(diào)制青貯飼料。添加乳酸菌促進(jìn)乳酸發(fā)酵,抑制丁酸發(fā)酵,提高了青貯飼料的發(fā)酵品質(zhì)。乳酸菌的生長和活性受發(fā)酵天數(shù),乳酸菌的初始種群,水溶性碳水化合物和干物質(zhì)含量的影響[1]。本研究的目的是分離乳酸菌,通過16S r DNA序列鑒定并確定其對象草和甜高粱青貯飼料發(fā)酵品質(zhì)的影響。本研究將為開發(fā)乳酸菌資源的合理利用提供理論依據(jù)。試驗(yàn)共分為四部分。1.象草青貯飼料中乳酸菌菌株的分離、鑒定本試驗(yàn)旨在從象草青貯飼料中分離、鑒定乳酸菌,為研究新的乳酸菌菌株和篩選潛在的優(yōu)良乳酸菌菌株奠定基礎(chǔ)。象草（Pennisetum purpureum）種植在中國江蘇省南京農(nóng)業(yè)大學(xué)實(shí)驗(yàn)田（北緯32°01′19″,東經(jīng)118°51′08″,海拔17 m）。從小型發(fā)酵系統(tǒng)制備的象草青貯飼料中分離出176株產(chǎn)乳酸菌株,并基于形態(tài)學(xué),生理學(xué)和生物化學(xué)特性以及16S rRNA分析鑒定了 7株這些菌株。結(jié)果表明,所有這7株分離乳酸菌菌菌均為同型發(fā)酵乳酸菌,并且能夠在pH 3.5環(huán)境下生... 

【文章來源】：南京農(nóng)業(yè)大學(xué)江蘇省211工程院校教育部直屬院校

【文章頁數(shù)】：122 頁

【學(xué)位級別】：博士

【文章目錄】：
摘要
ABSTRACT
LIST OF ABBREVIATIONS
CHAPTER-1 INTRODUCTION
    1.1.Background
    1.2.General characteristics of tropical grasses
    1.3.Potential grasses for tropical silage making
        1.3.1 Elephant grass(Pennisetum purpureum)
        1.3.2 Sorghum(sorghum bicolor)
    1.4.Principles of ensiling
    1.5.Characteristics of grasses affecting the fermentation quality of silage
    1.6.Silage fermentation processes
        1.6.1.Aerobic phase
        1.6.2.Fermentation phase
        1.6.3.Stable phase
        1.6.4.Feed-out Phase/ aerobic spoilage phase
    1.7.Factors affecting the ensiling process
        1.7.1.grasses
        1.7.2.Grass dry matter
        1.7.3.Buffering capacity of grass
        1.7.4.Mechanical treatments of grasses
        1.7.5.Density
    1.8.Micro-organisms involved in the ensiling process
        1.8.1 LAB and their effects on the fermentation quality of silage
        1.8.2 Obligate heterofermentative LAB
        1.8.3 Enterobacteria
        1.8.4 Clostridia
        1.8.5 Fungi
        1.8.6 Bacilli
    1.9.Isolation and screening of lactic acid bacteria
    1.10.Physiology of lactic acid bacteria
    1.11.Phenotypic characterization
    1.12.Genotypic characterization
    1.13.Aerobic stability test
        1.13.1.Microbial,chemical and physical changes during aerobic exposure
        1.13.2.Effect of aerobic spoilage on silage quality
        1.13.3.Effect of homofermentative Lactic acid bacteria on aerobic stability
    1.14 Effect of heterofermentative LAB on aerobic stability
    1.15.Objectives of the study
CHAPTER-2 Isolation and characterization of LAB strains from elephant grass
    1.Introduction
    2.Material and methods
        2.1.Isolation of LAB from elephant grass silage
        2.2.Morphological and physiological tests of LAB
        2.3.Extraction of lactic acid bacteria genomic DNA
        2.4.Sequence alignments and phylogenetic implications
        2.5.Storage of LAB isolates
    3.Results
        3.1.The morphological and physiological properties of characteristic strains isolates
        3.2.16S rRNA gene sequence analysis
        3.3.Amplification products obtained from the recA gene multiplex assay
    4.Discussion
    5.Conclusion
Chapter-3 Effect of lactic acid bacteria isolates on the fermentation quality of elephantgrass during ensiling
    1.Introduction
    2.Material and methods
        2.1.Silage preparation
        2.2.Chemical analyses
        2.3.Microbial population
        2.4.Statistical analyses
    3.Result
        3.1.Characteristics of elephant grass
        3.2.Effect of LAB isolates on pH,DM,WSC and NH3-N of elephant grass duringensiling
        3.3.Effect of LAB isolates on the organic acids of elephant grass during ensiling
        3.4.Effect of LAB isolates on microbiological composition of elephant grass duringensiling
    4.Discussion
        4.1.Microbiological composition
    5.Conclusion
Chapter-4 Effects of lactic acid bacteria isolates on the fermentation quality of sweetsorghum silage during ensiling
    1.Introduction
    2.Material and methods
        2.1.Forage harvesting
        2.2.Silage preparation
        2.3.Chemical analyses
        2.4.Microbial population
        2.5.Statistical analyses
    3.Result
        3.1.Characteristic of sweet sorghum
        3.2.Effect of LAB isolates on fermentation quality of sweet sorghum during ensiling
        3.3.Effect of LAB isolates on organic acids of sweet sorghum during ensiling
        3.4.Effect of LAB isolates on microbiological compositions of sweet sorghum silageduring ensiling
        3.5.Fermentation quality of sweet sorghum silages after 90 days of ensiling
    4.Discussion
    5.Conclusions
Chapter-5 Effects of LAB on the fermentation quality and aerobic stability of elephantgrass silage during ensiling
    1.Introduction
    2.Material and methods
        2.1.Forage harvesting
        2.2.Silage preparation
        2.3.Aerobic stability
        2.4.Chemical analyses
        2.5.Microbial population
        2.6.Statistical analyses
    3.Results
        3.1.Characteristic of elephant grass
        3.2.Effect of LAB isolates on fermentation quality of elephant grass
        3.3.Effects of LAB isolates on organic acids of elephant grass silage during ensiling
        3.4.Fermentation quality of elephant grass silages after 90 days
        3.5.Effect of LAB isolates on microbiological compositions
        3.6 Aerobic stability of elephant grass silage
            3.6.1 Effect of LAB isolates on organic acids composition of elephant grass silageduring aerobic exposure
            3.6.2.Effect of LAB isolates on fermenation quality of elephant grass silage duringaerobic exposure
    4.Discussion
        4.1.Aerobic stability of elephant grass silage
    5.Conclusion
CONCLUSION
RECOMMENDATIONS AND SCOPE FOR FURTHER RESEARCH
INNOVATION
REFERENCES
APPENDICES
ACKNOWLEDGEMENTS
LIST OF PUBLICATIONS


【參考文獻(xiàn)】：
期刊論文
[1]The Effect of Microbial Inoculants Applied at Ensiling on Sorghum Silage Characteristics and Aerobic Stability[J]. Ashbell G,Weinberg Z G.  Agricultural Sciences in China. 2002(10)



本文編號：3623397