Associations between meal size, gastric emptying and post-prandial plasma glucose, insulin and lactate concentrations in meal-fed cats.

Abstract

Plasma glucose and insulin concentrations are increased for 12-24h in healthy cats following moderate- to high-carbohydrate meals. This study investigated associations between gastric emptying time and post-prandial plasma glucose, insulin and lactate concentrations in cats fed an extruded dry, high-carbohydrate, moderate-fat, low-protein diet (51, 28, 21% metabolizable energy, respectively) once daily by varying meal volume. Eleven healthy, non-obese, neutered adult cats were enrolled in a prospective study and fed to maintain body weight. Ultrasound examinations were performed for up to 26h, and blood collections over 24h after eating meals containing approximately 100% and 50% of the cats' daily caloric intake (209 and 105kJ/kg BW, respectively). Gastric emptying time was increased after a meal of 209kJ/kg BW compared with 105kJ/kg BW (median gastric emptying times 24 and 14h, respectively; p=0.03). Time for glucose to return to fasting was longer after the 209kJ/kg BW meal (median 20h; 25th and 75th percentiles 15 and 23h, respectively) than the 105kJ/kg BW meal (13, 12 and 14h; p<0.01); however, peak glucose was not higher after the 209kJ/kg BW meal compared with the 105kJ/kg BW meal [(mean±SD) 6.6±0.6 and 7.8±1.2mmol/l, respectively, p=0.07]. Times for insulin to return to fasting were not significantly longer after the 209kJ/kg BW meal than the 105kJ/kg BW meal (p=0.29). d- and l-lactate concentrations were not associated with gastric emptying time or post-prandial blood glucose and insulin. Based on results obtained, prolonged gastric emptying contributes to prolonged post-prandial hyperglycemia in cats meal fed a high-carbohydrate, low-protein, dry diet and fasting times for cats' meal-fed diets of similar composition should be 14-26h, depending on meal size.