| The studies described in this thesis were designed to characterize disaccharidase activity and sodium-glucose transporter 1 (SGLT1) protein and mRNA distribution in the small intestines of pony foals from birth to 3 months of age and in mature horses fed different diets examining small intestinal adaptation to increased carbohydrate intake. Pony foals had significantly higher maltase activity with increasing age and a greater distribution of the gastrointestinal weight in the caecum and large intestine. No significant differences between age groups were found in SGLT1 protein expression and mRNA abundance. In mature horses, SGLT1 mRNA significantly increased in the duodenum after 1 month of grain feeding, and in the distal jejunum after 1 week of grain feeding, with a further increase after 1 month of high grain feeding. These changes suggest that SGLT1 increases in response to grain feeding to improve small intestinal absorptive capacity, but these changes are not evident during the development of foals to 3 months of age. |
