Influence of macronutrient composition of commercial diets on circulating leptin and adiponectin concentrations in overweight dogs.

Leptin and adiponectin play important roles in obesity-related inflammation and comorbidities. Previous research suggests that alterations in dietary macronutrient composition can modify circulating leptin and adiponectin concentrations in people, but limited research on this subject has been performed in dogs. This study investigated the effects of commercial high protein (HP), high fat (HF) and high carbohydrate medium protein (HCMP) diets on baseline (T-1 ) concentrations, post-prandial peak concentrations and total release in a ten-hour time span of leptin and adiponectin in dogs, when compared to a maintenance high carbohydrate low protein (HCLP) diet. Thirty-six overweight dogs were fed the HCLP diet in a one-week control period, after which the animals were assigned to one of three groups. In three four-week periods, each group was fed all test diets in a different sequence. At the last day of each period, blood was sampled at one hour before feeding (T-1 ) and at three (T3 ), six (T6 ) and nine (T9 ) hours after feeding. Feeding caused peak leptin concentrations at T6 and T9 (p < .001). No significant post-prandial change in adiponectin concentrations was found (p = .056). The HP diet resulted in lower leptin peak concentrations (p = .004) and AUCT-1-T9 (p = .01), but none of the diets influenced baseline leptin concentrations (p = .273). Baseline adiponectin concentrations were lower for the HF diet (p = .018) and HCMP (p < .001), and the HP, HF and HCMP AUCT-1-T9 (p < .001) were lower compared with the HCLP diet. Female dogs had lower adiponectin baseline concentrations (p = .041) and AUCT-1-T9 (p = .023) than male dogs. In conclusion, the HP diet was associated with the lowest post-prandial peak leptin concentration and the least decrease in adiponectin release, suggesting that a HP diet may improve immune-metabolic health and post-prandial satiety in overweight dogs.