Effects of Mannan-Oligosaccharides and Xylo-Oligosaccharides on the Chicken

Effects of mannan-oligosaccharides and xylo-oligosaccharides on the chicken gut microbiota By Mohsen Pourabedin Department of Animal Science McGill University, Montreal August 2015 A thesis submitted to McGill University in partial fulfillment of the requirements for the degree of Doctor of Philosophy © Mohsen Pourabedin, 2015 Table of contents Abstract .......................................................................................................................................... v Acknowledgements .................................................................................................................... viii Contributions of authors ............................................................................................................. ix List of tables.................................................................................................................................. xi List of figures ............................................................................................................................... xii List of abbreviations .................................................................................................................. xiv Chapter 1. General introduction ............................................................................................ 1 1.1 Objectives ....................................................................................................................... 3 1.2 References ....................................................................................................................... 4 Chapter 2. Literature review .................................................................................................. 5 2.1 Chicken gut microbiota ................................................................................................... 5 2.1.1 Gut microbiota and chicken health ............................................................................. 9 2.1.2 Gut microbiota and chicken growth .......................................................................... 11 2.1.3 Environmental effects on the gut microbiota ............................................................ 12 2.1.4 Culture-independent methods for the analysis of gut microbiota ............................. 13 2.2 Antibiotic growth promoters in poultry production ...................................................... 15 2.2.1 Virginiamycin ........................................................................................................... 17 2.2.2 Effects of antimicrobials on the chicken gut microbiota .......................................... 18 2.2.3 Resistance to antibiotics ............................................................................................ 19 2.2.4 Alternatives to antibiotic growth promoters ............................................................. 20 2.3 Prebiotics....................................................................................................................... 21 2.3.1 Mannan Oligosaccharides (MOS) ............................................................................. 25 2.3.2 Xylo-oligosaccharides (XOS) ................................................................................... 27 2.3.3 Alleviation of environmental stress by prebiotics .................................................... 30 2.4 Enteric pathogens in chickens ....................................................................................... 31 2.4.1 Intestinal pathogenesis of Salmonella Enteritidis ..................................................... 32 2.4.2 Chicken immune response to Salmonella infection .................................................. 33 2.4.3 Prebiotics for Salmonella control in poultry ............................................................. 34 i 2.5 Summary ....................................................................................................................... 36 2.6 References ..................................................................................................................... 37 Chapter 3. Effects of Mannan-oligosaccharides and Virginiamycin on the Cecal Microbial Community and Intestinal Morphology of Chickens Raised under Sub-optimal Conditions….. .............................................................................................................................. 59 3.1 Abstract ......................................................................................................................... 60 3.2 Introduction ................................................................................................................... 61 3.3 Material and Methods ................................................................................................... 63 3.3.1 Birds, Diet and Experimental Design ....................................................................... 63 3.3.2 Bacterial Culture Analyses and Intestinal Morphology ............................................ 64 3.3.3 DNA extraction ......................................................................................................... 65 3.3.4 DGGE Analyses of 16S rDNA ................................................................................. 65 3.3.5 Real-time PCR Analysis ........................................................................................... 66 3.3.6 Data Analyses ........................................................................................................... 67 3.4 Results ........................................................................................................................... 68 3.4.1 DGGE and diversity indices ..................................................................................... 68 3.4.2 Bacterial Enumeration .............................................................................................. 71 3.4.3 Intestinal Morphology ............................................................................................... 75 3.4.4 Growth performance ................................................................................................. 77 3.5 Discussion ..................................................................................................................... 79 3.6 Conclusion .................................................................................................................... 82 3.7 Acknowledgements ....................................................................................................... 83 3.8 References ..................................................................................................................... 83 Connecting text............................................................................................................................ 88 Chapter 4. Xylo-oligosaccharides and Virginiamycin Differentially Modulate Gut Microbial Composition in Chickens. ......................................................................................... 89 4.1 Abstract ......................................................................................................................... 90 4.2 Introduction ................................................................................................................... 91 4.3 Materials and Methods .................................................................................................. 93 4.3.1 Birds, diet and experimental design .......................................................................... 93 4.3.2 Sample collection and DNA extraction .................................................................... 94 ii 4.3.3 Pyrosequencing ......................................................................................................... 95 4.3.4 Data processing ......................................................................................................... 95 4.3.5 Cecal SCFA and lactate concentrations .................................................................... 96 4.3.6 Statistical measurements ........................................................................................... 96 4.4 Results ........................................................................................................................... 97 4.4.1 Sequence analysis and quality filtering..................................................................... 97 4.4.2 Effects of dietary treatments on the ileal microbiota ................................................ 98 4.4.3 Effects of dietary treatments on the cecal microbiota ............................................. 100 4.4.4 Comparison between the ileal and the cecal microbiota ......................................... 103 4.4.5 Temporal changes in the ileal and the cecal microbiota ......................................... 106 4.4.6 SCFAs in the ileum and cecum ............................................................................... 110 4.4.7 Growth Performance ............................................................................................... 112 4.5 Discussion ................................................................................................................... 113 4.6 Acknowledgements ..................................................................................................... 117 4.7 References ................................................................................................................... 117 Connecting Text .......................................................................................................................

Load more