尼罗罗非鱼肠道芽孢杆菌的分离、鉴定及益生性评价

发布时间：2022-08-04 12:19

　　罗非鱼是全球养殖总量仅低于鲤鱼的水产养殖品种之一。它是许多发达国家和发展中国家人民的重要蛋白质来源。为了满足对鱼类的高需求,罗非鱼通常养殖密度较高,导致养殖罗非鱼疾病时常发生,对水产养殖业造成了重大打击。在水产养殖中,益生菌在抗病、提高免疫力、改善水质等方面的应用得到了很好的阐明。然而,在水产养殖中使用的益生菌很多并非来源于鱼体,因此,它们在水产动物上应用的效果相对较差。宿主相关的益生菌,即“最初从养殖水体或宿主的消化道中分离出来,以改善宿主的生长和健康的细菌”,被认为是水产养殖业的未来。在许多候选微生物中,益生芽孢杆菌由于具有孢子形成能力,使它们在恶劣环境条件下（耐热和更长的寿命）存活,此外,多数芽孢杆菌对鱼类没有致病性且无毒,并能产生广泛的抗菌物质,因此比其他益生菌更适合作为候选益生菌。因此,本论文从罗非鱼消化道中分离和鉴定芽孢杆菌,通过体外实验对其形态、生化和抑菌活性等进行研究,通过养殖实验,对其体内益生菌潜力进行了评估,研究了不同菌株对尼罗罗非鱼生长、消化酶和抗氧化酶能力、血清和粘液免疫、基因表达的影响及其对尼罗罗非鱼菌群和肠道形态的影响。同时,通过人工感染实验,对分离的芽孢杆... 

【文章页数】：171 页

【学位级别】：硕士

【文章目录】：
Abstract
摘要
1 General Introduction
    1.1 Background of the Study
    1.2 Literature Review on the Application of Bacillus as Probiotics in Aquaculture
        1.2.1 Characteristics and Morphology of Bacillus Species
        1.2.2 Modulation of Antioxidant Enzymes by Bacillus Species
        1.2.3 Stress Mitigation by Bacillus Species
        1.2.4 Tissue Protection by Bacillus Species
        1.2.5 Bacillus Species Enhances Immune Response in Fish
        1.2.6 Bacillus Species Improve Feed Utilization and Growth
        1.2.7 Bacillus Species Increases Disease Resistance in Aquatic Organism
    1.3 Purpose of the Study
    1.4 The Scientific Significance of the Study
    1.5 The Aim and Scope of the Study
    1.6 Technical Routes of Study
2 In Vitro Assessment of the Probiotic Characteristics of Three Bacillus Species from the Gut of Nile Tilapia,Oreochromis niloticus
    2.1 Introduction
    2.2 Materials and Methods
        2.2.1 Sample Collection
        2.2.2 Isolation of Gut Bacteria
        2.2.3 Biochemical Characterisation
        2.2.4 Growth of Bacteria in Luria-Bertani Broth
        2.2.5 Biosafety Assay
        2.2.6 Antibiotic Susceptibility
        2.2.7 Resistance to Bile Salts
        2.2.8 Resistance to High Temperature
        2.2.9 Compatibility of the Three Isolates
        2.2.10 Antimicrobial Activity
        2.2.11 Auto-aggregation
        2.2.12 Cell Hydrophobicity
        2.2.13 Haemolytic Activity
        2.2.14 Determination of Optimal Growth and p H
        2.2.15 Detection of Biofilm Formation(Congo Red Agar Method)
        2.2.16 Statistical Analysis
    2.3 Results
        2.3.1 Identification of Gut Bacteria
        2.3.2 Biochemical and Morphological Characterisation
        2.3.3 Growth Curve(in Lb)Using OD
        2.3.4 Biosafety Assay
        2.3.5 Antibiotic Susceptibility
        2.3.6 Resistance to Bile Salt
        2.3.7 Resistance to High Temperature
        2.3.8 Compatibility of the Three Isolates
        2.3.9 Antimicrobial Activity
        2.3.10 Auto-aggregation
        2.3.11 Cell Hydrophobicity
        2.3.12 Haemolytic Activity
        2.3.13 Determination of Optimal Growth and p H
        2.3.14 Detection of Biofilm Formation(Congo Red Agar Method)
    2.4 Discussion
    2.5 Conclusion
3 In Vivo Assessment of the Probiotic Potentials of Three Host-Associated Bacillus Species on Growth Performance,Health Status and Disease Resistance of Oreochromis niloticus Against Streptococcus agalactiae
    3.1 Introduction
    3.2 Materials and Methods
        3.2.1 Diet and Probiotics Spore Preparation
        3.2.2 Experimental Set-up and Fish Management
        3.2.3 Sampling
        3.2.4 Analysis
        3.2.5 Challenge Test
        3.2.6 Statistical Analysis
    3.3 Results
        3.3.1 Growth Performance
        3.3.2 Digestive Enzymes Activities
        3.3.3 Serum Immune Parameters
        3.3.4 Serum Antioxidant Enzymes
        3.3.5 Serum GPT and GOT Activities
        3.3.6 Gene Expression
        3.3.7 Challenge Test
    3.4 Discussion
    3.5 Conclusion
4 Effects of Three Host-Associated Bacillus Species on Mucosal Immunity and Gut Health of Nile Tilapia,Oreochromis niloticus and its Resistance against Aeromonas hydrophila Infection
    4.1 Introduction
    4.2 Materials and Methods
        4.2.1 Diet and Probiotics Spore Preparation
        4.2.2 Experimental Set-up and Fish Management
        4.2.3 Sampling
        4.2.4 Determination of Enzymes Activities
        4.2.5 Histological Analysis
        4.2.6 Intestinal Microbiota Analysis
        4.2.7 Challenge Test
        4.2.8 Statistical Analysis
    4.3 Results
        4.3.1 Fish Response to Experimental Diets
        4.3.2 Mucus Immune Parameters
        4.3.3 Mucus Antioxidant Enzymes Activity
        4.3.4 Intestinal Immune Parameters
        4.3.5 Intestinal Antioxidant Enzymes Activity
        4.3.6 Intestinal Digestive Enzymes Activity
        4.3.7 Histology of the Intestine
        4.3.8 Intestinal Microbiota
        4.3.9 Challenge Test
    4.4 Discussion
    4.5 Conclusion
5 General Conclusion and Recommendation
    5.1 Conclusion
    5.2 Recommendation
References
Acknowledgement
Author's Profile
Publications
Special Honours and Awards
Supervisor's Profile
Supplementary data


【参考文献】：
期刊论文
[1]Effects of dietary probiotic supplementation on the growth,gut health and disease resistance of juvenile Nile tilapia（Oreochromis niloticus）[J]. Yun Xia,Miao Wang,Fengying Gao,Maixin Lu,Gang Chen.  Animal Nutrition. 2020(01)



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