Circulating lipid profiles and post-prandial glucose and insulin in response to dietary macronutrient composition in...

Insulin response to a meal is crucial for metabolic health in cats, influencing the risk of metabolic disorders.

Investigate dietary macronutrient compositions on fasted and post-prandial insulin and glucose responses, and lipid profiles, in lean and obese cats.

Nine lean and 9 obese, male neutered colony cats.

Cats were fed 3 extruded dry diets: low protein (LP: 28% protein, 40% fat, and 32% nitrogen-free extract [NFE]), low fat (LF: 40% protein, 30% fat, and 30% NFE), and low carbohydrate (LC: 36% protein, 41% fat, and 23% NFE) for 28 days using a 3 × 3 Latin square design. Fasted and post-prandial blood samples were collected to measure serum insulin and whole blood glucose concentrations, and fasted samples were analyzed for serum cholesterol, triacylglycerol (TAG), nonesterified fatty acid (NEFA), very low-density lipoprotein (VLDL), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) concentrations at the end of each period.

No differences were found in serum insulin, glucose, cholesterol, NEFA, TAG, HDL-c, LDL-c, or VLDL concentrations between lean and obese cats (P > .05) suggesting dyslipidemia was not present in the obese cats. The LP diet resulted in lower post-prandial insulin concentrations compared with the LC and LF diets (P = .01) which was attributed to lower protein intake with the LP diet. As expected, the LF diet led to lower fasted serum cholesterol and LDL-c concentrations compared with the LP and LC diets (P < .001).

These findings document the metabolic flexibility of cats and suggest that dietary macronutrient composition, particularly protein content, plays an important role in modulating insulin responses in adult, otherwise healthy, cats.