Secretion of incretins such as glucose-dependent insulinotropic peptide (GIP) and glucagon like peptide-1 (GLP-1) is stimulated various macronutrients (especially dietary carbohydrates and fats) in human and other mammals. Moreover, in humans, two different fat sources (lard, which is high in saturated fatty acids, and soybean oil, which is high in unsaturated fatty acids) induced different degrees of GLP-1 and GIP secretion. In this study, we investigated the impact of two different fat sources (lard and soybean oil) on the post-prandial serum concentrations of glucose, insulin, triglycerides, non-esterified fatty acid (NEFA), GIP and GLP-1 concentrations in six healthy cats. We fed a basal diet (low-fat diet) and the basal diet with two sources of fat (lard and soybean oil) (high-fat diets). Each diet was fed for 14 days. Significant differences in the postprandial NEFA and GIP concentrations were observed between the high-fat diets and the basal diet. No significant difference was observed in the serum glucose, insulin, triglyceride, or GLP-1 concentrations among the 3 diets. The different fat sources might not have a significant effect on postprandial GIP secretion in cats.
We conducted this study to elucidate the effects of dietary calcium concentrations on urinary and fecal concentrations and amounts of excretion of oxalate in cats as well as the effects on those of calcium. We prepared three test diets the concentrations of calcium of which were 0.7, 1.5, and 1.9%, respectively, as DM basis and fed these diets at maintenance level to four adult male cats. The cats were assigned to three groups and the feeding trial was conducted based on a 3×3 latin square design where the length of one period was 30 days. We collected the samples of urine and feces during the last 10 days of each period. Neither the concentrations nor the amounts of excretion of calcium in urine were affected by the dietary calcium concentrations. The dietary calcium concentrations did not affect those of oxalate. On the other hand, the higher dietary calcium concentrations resulted in higher concentrations and higher amounts of excretion of calcium in feces (P＜0.01). Further, although concentrations of oxalate in feces were not affected by the dietary calcium concentrations, the higher dietary calcium concentrations resulted in higher amounts of excretion of oxalate in feces (P＜0.05). We revealed in this study that the higher calcium concentrations in feline diets results in higher amounts of excretion of oxalate in feces. However, we also observed that higher dietary calcium resulted in lower serum calcium concentrations. We need to examine the effects of longer period of higher dietary calcium feeding on serum calcium concentrations in cats.