The effects of differing proportions of dietary macronutrients on the digestibility and post-prandial endocrine responses in domestic cats (Felis catus)

Abstract

SummaryThe aim of this study was to compare the effects of feeding two diets with different macronutrient proportions (high protein, low carbohydrate and low protein, high carbohydrate) on the digestibility and post-prandial endocrine responses of cats fed at maintenance levels, and to evaluate the effectiveness of the marginal ear vein prick technique for the measurement of blood glucose levels in feline studies. Two diets were fed to 16 adult domestic short-haired cats for a period of three weeks (eight cats per diet). Following a seven-day dietary adaptation period, the apparent macronutrient digestibility of the two diets was determined (days 8-19) using the total faecal collection method. The faeces were freeze dried, ground and analysed for dry matter, crude protein, crude fat and gross energy and then apparent digestibility was calculated. On days 20 and 21, the post-prandial glucose responses of the cats fed a single meal of one of the two diets were measured in serial blood samples collected using the marginal ear vein prick technique.Results showed that the high protein, low carbohydrate diet had higher (p < 0.05) apparent digestibility of dry matter, crude protein, crude fat and energy, lower (p < 0.01) daily faecal output and smaller fluctuations in blood glucose concentrations. Despite the two groups of cats having similar calorific intakes, the cats fed the high protein diet lost weight over the study period, whereas those fed the high carbohydrate, low protein diet gained weight. The marginal ear vein prick technique proved to be an effective alternative to catheterisation for blood glucose determination. The high protein diet tested in the current study, in addition to being more aligned to the cat's natural carnivorous diet, may be beneficial for weight management and blood glucose control in cats.