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Browsing by Subject "dieetti"

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  • Huurinainen, Outi (University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2009)
    Microbiota inhabiting the colon fermentate carbohydrates, proteins and endogenous substrates to volatile fatty acids (VFA) and produce energy for the microbial growth. Because all species of bacteria ferment some component of the digesta and produce various VFAs, alterations in microflora may modify these fermentative end products. Thus, measuring the amount and type of VFA produced gives an instrument which reflects changes in the bacterial microbiota of the intestine. This study set out to explain the connections between diet composition and the formation of VFAs. The general hypothesis was that different food compositions cause differences in the VFA profile, and this may have systemic effect on animal health. Graeco Latin Square design study with 5 healthy Beagles was performed, feeding high protein (diet A, starch 54 g/kg, crude protein 609 g/kg), high carbohydrate (diet B, starch 438 g/kg, crude protein 194 g/kg), and a balanced commercial (diet C, starch 277 g/kg, crude protein 264 g/kg) diets for three weeks each. The diet C was used also for the baseline. VFA, fecal dry matter and fecal consistency score were assessed. All dogs had formed feces during diets B and C but diarrhea during diet A, leading to significant differences in fecal consistency score between the diets (p < 0.0001). The results indicate that alterations in diet had a large influence on the amount and quality of VFAs produced. Mixed-effect model analysis shows that the diets had a statistically significant (p<0.05) influence on all of the VFAs produced excluding butyric acid. The most significant changes from the baseline diet were seen with the high protein diet. Compared to the baseline diet, valeric acid production increased 24-fold, isobutyric acid by 79.5% and isovaleric acid by 42.4 %. Production of propionic acid decreased by 43.3%, acetic acid by 25.0%, and butyric acid by 10.2 %. In previous studies similar changes in VFA profile have been coupled with various intestinal diseases as well as inhibition in biotin absorption. Furthermore, this might have an influence on inflammatory response at the cellular level. Thus, changes in VFA profile may have an influence at least on the local intestinal health. The total amount of fatty acids decreased on both experimental diets. It seems that having moderate protein and carbohydate levels in the diet is a virtue and more is not necessarily better. This study provides additions to existing understanding of the relationship between diet composition and the formation of VFAs in the intestine. The findings suggest that observing the alterations in VFA levels formed in the intestine and therefore present in feces, may provide an instrument to indirectly observe changes in the bacterial microbiota of the intestine. Thus, there is a need to find the link between the changes in VFA profiles and colonic microbiota, and bacterial diversity in feces by using molecular methods. Having this greater level of understanding would lead to more robust insights into the role of intestinal microbiota in animal health, and to potential advances in the prevention and curing of related diseases.
  • Seppälä, Tiina (2019)
    Equine digestive tract is adapted to diets rich in fibre. Concentrates are commonly used as energy supplements. The aim of this meta-analysis was to study the effect of concentrate level and diet composition, especially the amount of starch and non-structural carbohydrates (NSC), on diet digestibility. The data consisted of 23 studies, 50 different diet comparsions and 113 diets, in which the concentrate level varied from 0 to 80 %. Dry matter, crude protein, neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibilities were measured by total collection or internal markers in all of the studies. Statistical analysis was performed using regression analysis with linear and quadratic mixed models. Concentrates were divided to three classes by the main ingredient: (1) fibre-rich, (2) oat-based and (3) other cereal (barley, corn) concentrates. Dry matter digestibility improved when the concentrate level and the starch level rose, but the effect faded with high levels according to the quadratic model (p=0,04 both). Increase of dietary starch level (g/bodyweight/meal) had a negative effect on fibre digestibility in both starch rich concentrate classes 2 and 3. NDF digestibility decreased curvilinearly when the level of NSC in diet (p=0,01) and in roughage (p=0,03) increased. There was no relationship between diet digestibility and concentrate NDF-level (p>0,25). Improved dry matter digestibility with increasing concentrate level can be explained by increased enzymatic digestion in the small intestine. When dietary level of starch and NSC is increased, part of the undigested matter can interfere with the caecum microbial balance and decrease fibre digestion. The results imply that, in addition to starch, dietary NSC level should be taken into account when evaluating the effects of diet composition on fibre digestibility in horse, even if the horse doesn’t have any metabolic problems. Further research on the effect of NSC on caecal microbial fermentation in healthy horses is warranted.