Mannoheptulose has differential effects on fasting and postprandial energy expenditure and respiratory quotient in adult Beagle dogs fed diets of different macronutrient contents

Abstract

The present study aimed to determine the effects of mannoheptulose (MH) (8 mg/kg) on energy expenditure (EE), respiratory quotient (RQ) and glycaemic response in healthy adult Beagle dogs (n 8; 9·62 (sem 0·31) kg; body condition score 4·5). The study was designed as replicated 4 × 4 Latin squares with a 2 × 2 factorial treatment structure. The dietary treatments were low carbohydrate (CHO) relative to fat diet (LC; 31 % CHO, 28 % fat) with placebo (0 mg/kg) or MH supplement and high CHO relative to fat diet (HC; 54 % CHO, 11 % fat) with placebo (0 mg/kg) or MH supplement. Dogs were fed to maintain body weight (HC and HC+MH 3625 (sem 295) kJ and LC and LC+MH 3542 (sem 284) kJ). Resting and postprandial (0–4 h; 5–10 h; 11–17 h; 18–23 h) EE and RQ were determined by indirect calorimetry (days 12 or 14). Glycaemic response to a meal (24 h) and plasma MH concentrations were determined on days 12 or 14. Plasma MH followed first-order kinetics, confirming that MH is absorbed and available to the animal. In the presence of high dietary CHO, MH increased postprandial EE (5–10 h only), suggesting MH increased dietary induced thermogenesis. In contrast to earlier reports, MH did not affect serum glucose or insulin in the present study. Irrespective of MH, dogs adapted RQ to diet composition and dogs consuming the LC diet had a greater incremental AUC for glucose, but not insulin, than dogs consuming the HC diet.

Dietary Mannoheptulose Increases Fasting Serum Glucagon Like Peptide-1 and Post-Prandial Serum Ghrelin Concentrations in Adult Beagle Dogs

“…In Labrador Retrievers fed a dietary dose of 4 mg/kg, decreases in post-prandial energy expenditure and respiratory quotient (RQ) were observed [ 9 ]. Conversely, in Beagles fed an oral cocoa butter based supplement containing 8 mg/kg BW MH with a high carbohydrate relative to fat diet, an increase in post-prandial energy expenditure was noted [ 10 ]. Neither study observed changes in serum glucose or insulin with MH feeding.…”

Dietary mannoheptulose does not alter glucose or lipid metabolism in adult Labrador Retrievers

“…Like McKnight, Flickinger, France, et al. () and McKnight, Root‐McCaig et al. (), the diet used in the present study had high inclusion of dietary sorghum which has been demonstrated to minimize post‐prandial glucose and insulin responses in dogs (Carciofi et al., ), making it difficult to observe notable changes in glucose metabolism associated with MH feeding, especially in healthy adult animals receiving superior veterinary care.…”

“…Indeed, McKnight, Flickinger, France, et al. () demonstrated that plasma MH concentrations peak within 3 hr of ingestion and return to non‐detectable levels within 24 hr of ingestion of a dietary MH supplement (8 mg/kg BW). These findings demonstrate that ingested MH is absorbed and available to the animal.…”

“…However, it is worth noting that McKnight, Flickinger, France, et al. () fed MH in the presence of a diet high in carbohydrate relative to fat and a diet low in carbohydrate relative to fat concentrations. Dietary ingredients and their inclusion concentrations are known to influence glucose metabolism in dogs, irrespective of MH (Carciofi et al., ).…”

“…Green tea extract did not impact body weight but improved insulin sensitivity and decreased circulating triglycerides in obese insulin resistant Beagles (Serisier et al., ). Mannoheptulose (MH), a novel functional feed ingredient, is under preliminary investigation (McKnight, Erye, Gooding, Davenport, & Shoveller, ; McKnight, Flickinger, Davenport, France, & Shoveller, ; McKnight, Flickinger, France, Davenport, & Shoveller, ; McKnight, Root‐McCaig et al., ).…”