Colon/chemistry; Diabetes Mellitus, Type 1/etiology; Diet; Glucagon/genetics; Intestine, Small/chemistry; Protein Precursors/genetics; RNA, Messenger/analysis; Age Factors; Animals; Blood Glucose/analysis; Blood Glucose/metabolism; Colon/metabolism; Diabetes Mellitus, Type 1/genetics; Diabetes Mellitus, Type 1/prevention & control; Diet/adverse effects; Female; Gene Expression Regulation, Developmental/genetics; Glucagon/blood; Glucagon/metabolism; Glucagon-Like Peptide 1; Glucose Transporter Type 1; Glucose Transporter Type 2; Intestine, Small/metabolism; Male; Membrane Glycoproteins/genetics; Membrane Glycoproteins/metabolism; Monosaccharide Transport Proteins/genetics; Monosaccharide Transport Proteins/metabolism; Peptide Fragments/blood; Peptide Fragments/metabolism; Proglucagon; Protein Precursors/blood; Protein Precursors/metabolism; RNA, Messenger/genetics; RNA, Messenger/metabolism; Rats; Rats, Inbred BB; Sodium-Glucose Transporter 1