羅非魚是全球養(yǎng)殖總量僅低于鯉魚的水產(chǎn)養(yǎng)殖品種之一。它是許多發(fā)達國家和發(fā)展中國家人民的重要蛋白質(zhì)來源。為了滿足對魚類的高需求,羅非魚通常養(yǎng)殖密度較高,導致養(yǎng)殖羅非魚疾病時常發(fā)生,對水產(chǎn)養(yǎng)殖業(yè)造成了重大打擊。在水產(chǎn)養(yǎng)殖中,益生菌在抗病、提高免疫力、改善水質(zhì)等方面的應(yīng)用得到了很好的闡明。然而,在水產(chǎn)養(yǎng)殖中使用的益生菌很多并非來源于魚體,因此,它們在水產(chǎn)動物上應(yīng)用的效果相對較差。宿主相關(guān)的益生菌,即“最初從養(yǎng)殖水體或宿主的消化道中分離出來,以改善宿主的生長和健康的細菌”,被認為是水產(chǎn)養(yǎng)殖業(yè)的未來。在許多候選微生物中,益生芽孢桿菌由于具有孢子形成能力,使它們在惡劣環(huán)境條件下（耐熱和更長的壽命）存活,此外,多數(shù)芽孢桿菌對魚類沒有致病性且無毒,并能產(chǎn)生廣泛的抗菌物質(zhì),因此比其他益生菌更適合作為候選益生菌。因此,本論文從羅非魚消化道中分離和鑒定芽孢桿菌,通過體外實驗對其形態(tài)、生化和抑菌活性等進行研究,通過養(yǎng)殖實驗,對其體內(nèi)益生菌潛力進行了評估,研究了不同菌株對尼羅羅非魚生長、消化酶和抗氧化酶能力、血清和粘液免疫、基因表達的影響及其對尼羅羅非魚菌群和腸道形態(tài)的影響。同時,通過人工感染實驗,對分離的芽孢桿... 

【文章頁數(shù)】：171 頁

【學位級別】：碩士

【文章目錄】：
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


【參考文獻】：
期刊論文
[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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