Association of Adiponectin Multimers with Dietary Nutrient Composition, Body Weight Gain, Meal Feeding, and Insulin Sensitivity in Cats
Adiponectin has been investigated widely due to its association with adiposity and the metabolic syndrome in human beings. Adiponectin circulates as low- (LMW) and high-molecular weight (HMW) multimers and the latter are the more bioactive forms. There are no reports of the relative proportion (distribution) of adiponectin multimers in feline plasma. The aim of this study was to assess the association of dietary nutrient composition, body weight gain, meal feeding, and insulin sensitivity with HMW adiponectin concentration and adiponectin multimer distribution in cats.
Healthy, neutered, young adult, mixed-breed cats (n=32) with ideal body weight were matched by gender, insulin sensitivity, and body weight, and were randomly allocated to either a low carbohydrate (19% metabolisable energy [ME]) or high carbohydrate (52% ME) diet. Cats were fed for 4 weeks at maintenance energy requirements, followed by 8 weeks of ad-libitum feeding. The distribution of adiponectin multimers in plasma (SA=HMW/(HMW+LMW)) was measured in a random sample of 16 of these cats (4 males and 4 females from each dietary group) after 3 and 8 weeks of feeding using velocity centrifugation on sucrose gradients followed by Western Blotting. The concentration of HMW adiponectin was obtained by multiplying the SA with the total adiponectin concentration measured by a commercial ELISA. The relationship of dietary nutrient composition, body weight gain, and insulin sensitivity with adiponectin multimer distribution and concentration were assessed using generalised linear models and linear regression. Paired t-tests assessed the effect of meal feeding on adiponectin profile before and 6 hours after eating.
Cats fed the high carbohydrate diet had higher fasting concentrations of HMW adiponectin than cats fed the low carbohydrate diet (4.6 ±2.2µg/ml and 2.2±1.6µg/ml, p=0.015), but there was no significant difference between diets 6 hours after eating, and the relative proportion of HMW to LMW adiponectin was not affected by diet. Neither HMW concentration nor distribution differed significantly at 6 hours after eating from fasting values (p>0.447). Mean percent body weight gain at 8 weeks was 22±14% (range 10% to 50%), and this was not associated with a corresponding change in adiponectin distribution or concentration of HMW adiponectin (p>0.632). Insulin sensitivity was not significantly associated with HMW concentration or with adiponectin distribution (p>0.140).
In conclusion, a high carbohydrate diet fed at maintenance energy requirements is associated with higher fasting but not postprandial concentrations of HMW adiponectin in cats; whereas insulin sensitivity, body weight gain, and meal feeding were not strongly associated with circulating HMW adiponectin concentration or adiponectin multimer distribution.