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Subject: search.filters.subject.Fiber in animal nutrition

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    Fibre fermentation in the ileum : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Sciences at Massey University, Palmerston North, New Zealand
    (Massey University, 2022) Hoogeveen, Anna Maria Elisabeth Hoogeveen
    Recently, several studies have suggested that the microbes present in the ileum (i.e., the end of the small intestine) can ferment dietary fibre resulting in organic acid production and contribute to the overall gastrointestinal tract (GIT) fermentation. However, studying human ileal fermentation is challenging due to inaccessibility of the small intestine. The aim was to validate a newly developed and optimised in vivo/in vitro ileal fermentation assay based on the growing pig as an animal model for human adults. After the assay was validated, this method was used to quantify ileal fermentation and compare this with large intestinal fermentation. In addition, the effect of diet on ileal fermentation and which factor was a greater contributor to in vitro ileal fermentation (inoculum or substrate) were studied. Firstly, in vitro ileal organic matter (OM) fermentability was similar to in vivo fermentability in the conventional grown pig. Artificially rearing and inoculating young pigs with an infant faecal inoculum did not improve the model. Secondly, the ileal microbiota from pigs and human ileostomates was found to have similar in vitro OM fermentability and organic acid production for arabinogalactan, fructooligosaccharides and pectin, even though some differences were found in the ileal microbial community. Therefore, the in vivo/in vitro ileal fermentation assay using conventional pigs is a preferred and valid model for studying ileal fermentation in the adult human. It was found that ileal fermentation was quantitatively significant and similar in magnitude to hindgut fermentation when using this validated assay. However, the microbial community and organic acid production (mainly acetic acid) in the ileum differed. It was also found that partly replacing cellulose with more fermentable fibres in the diet affected the ileal microbial community and its fermentative capacity in growing pigs. Lastly, the substrate (i.e., different fibre sources) was found to have a greater effect on ileal fermentation than the inoculum (i.e., different ileal microbiota obtained by feeding pigs different diets). In conclusion, this work has demonstrated the quantitatively significant contribution of ileal fermentation to overall GIT fermentation, and that the in vivo/in vitro ileal fermentation assay using the growing pig is a valid assay for studying ileal fermentation in the adult human. Dietary intervention can be used to shape ileal microbiota and fermentation.
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    Assessment of the effects of dietary fibre and animal-derived fermentable substrates on the gastrointestinal microbiome and associated faecal parameters of the domestic cat (Felis catus) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2021) Butowski, Christina Frances
    Globally, commercial diets high in animal protein and fat are becoming increasingly popular for pets. However, there is little research assessing the impacts of such diets in domestic cats. Dietary fibre and animal-derived fermentable substrates (ADFS) are of interest because of their role in gastrointestinal health. A series of in vivo and in vitro studies were conducted to determine the effects of ADFS on the food-host-microbiome interaction in the domestic cat. Initially, the impact of dietary fibre inclusion in a high protein raw meat diet on the faecal microbiome was determined (Chapter Two). Observations from this study suggested that a high protein raw meat diet was highly digestible and influenced the frequency of defecation in the domestic cat. As part of this study, I also assessed two methodologies. Firstly, the point at which the faecal microbiome should be sampled after diet adaption (Chapter Three) and secondly, the suitability of a rectal swab sample (Chapter Four) in determining the composition of the faecal microbiome. I ascertained that the faecal microbiome of the cat could ferment dietary fibre (inulin and cellulose). Furthermore, relative stability of the microbiome was reached after day 5. However, rectal swab samples did not replicate the taxonomic complexity of the faecal microbiome. Based on results from Chapter Two, I assessed the fermentative capacity of a range of ADFS compared to dietary fibre in vitro (Chapter Five). I found that hydrolysed collagen produced the greatest concentrations of butyrate in this system. Therefore, in the final study, I assessed the impacts of hydrolysed collagen inclusion in a high protein raw meat diet on the faecal metagenome (Chapter Six). Additionally, I assessed tryptophan metabolites as they include a key neurotransmitter, serotonin, which has local effects on the colon and may explain the differences in defecation frequency observed. I found that the hydrolysed collagen was fermented by the gastrointestinal microbiome of the domestic cat and could have the potential to replace dietary fibre in the diet of the domestic cat. From this, future research could verify the potential of ADFS in replacing dietary fibre in domestic cats. In addition, further work is required in determining the functional potential of the microbiome of the domestic cat to fully understand the impact of diet on the host-microbiome interactions.
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    Influence of bird type, dietary fibre and particle size on apparent ileal digestibility of nutrients and energy utilisation : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Animal Science at School of Agriculture and Environment, Massey University, Manawatu, Palmerston North, New Zealand
    (Massey University, 2018) Mtei, Asnath William
    Whilst limited published data are available on the effect of bird type on the nutrients digestibility and the interaction between DF content and bird type on nutrient digestibility, no study has investigated the interaction between dietary particle size and bird type on nutrient digestibility. In the present thesis work, it was hypothesised that the interaction exists in nutrient digestibility responses of different bird types to increased dietary fibre content and particle size, with layers showing better digestion efficiency in high fibre diets and to increased dietary particle size. The objectives of the experimental research presented in this thesis are, 1. To investigate the influence of bird type (broilers, pullets and layers) and DF content (low fibre and high fibre) on apparent ileal nutrient digestibility and energy utilisation; 2. To investigate the influence of bird type (broilers and layers) and maize particle size (fine, medium and coarse) on apparent ileal digestibility of nutrients and energy utilisation. The major finding of this research was that the bird type influenced the digestibility of nutrients regardless of diet type, with higher digestibility in broilers compared to pullets and layers. Bird types showed different magnitude of digestibility responses to increased dietary fibre content. Nutrient digestibility responses to dietary fibre content were greater in layers than in broilers and pullets. Although feeding medium and coarse particles was associated with increased gizzard and proventriculus weights in both layers and broilers, only the layers benefited in terms of increase nutrient digestibility. Overall, these findings demonstrate that the digestive tract development and function in layers is more sensitive to feed structure. The implication is that feeding diets low in fibre and finely ground diets to layers should be avoided to achieve optimum digestion. The interactions observed between diet type or particle size and bird type suggest that the information available on the dietary inclusion level of fibre sources and nutrient digestibility for one type of bird may not be appropriate for use in diet formulation for the other type of birds. However, further research is required to determine the dietary fibre level and particle sizes to be considered in diets for different bird types.--From Introduction & Discussion