Background – Following ingestion of a meal, postprandial hyperglycaemia in cats persists for 20-24 hrs, and the reasons for this are unknown.
Objectives – To describe the patterns of postprandial plasma glucose, D-lactate, and L-lactate concentrations, and gastric emptying time in meal-fed cats, and to assess the effects of meal volume on gastric emptying time.
Design – Eleven healthy cats were fed a commercially available, high carbohydrate (54% metabolisable energy) diet for 2 weeks. In the third week, on two separate occasions, fasted cats were fed a meal of 50 kcal/kg and consumed at least 90% within 30 mins. On the first occasion, the cats underwent repeated ultrasound examinations over 26 hrs to determine gastric emptying time. On the second occasion, plasma glucose, D-lactate and L-lactate concentrations were measured over 24 hrs. To assess the effect of volume of food eaten on gastric emptying time, 2 weeks later, five of the same cats were fed a meal of the same composition but half the volume (25 kcal/kg) and a second series of ultrasound examinations was performed.
Outcomes – Glucose concentrations were significantly higher than baseline from 1 to 18 hrs after feeding (P<0.001), reaching a peak at 10.7 ± 5.3 hrs (mean ± SD) after the meal. Median time to gastric emptying when cats were fed their total daily energy intake in a single meal was 24 hrs (range 16-26 hrs). In contrast, times to gastric emptying were substantially shorter when cats were fed 50% of their daily intake in a single meal (median 14 hrs; range 12-14 hrs). D- and L-lactate concentrations did not change substantially after feeding.
Conclusion – These results suggest that prolonged gastric emptying time contributes to the prolonged postprandial hyperglycaemia observed in meal-fed cats. They also show that gastric emptying is faster if the meal size is reduced.