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

Leslie L Mcknight,Anna K Shoveller,James France,Gary M Davenport,Elizabeth A Flickinger

doi:10.1017/jns.2014.17

Leslie L Mcknight, Anna K Shoveller + Show 3 more

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https://doi.org/10.1017/jns.2014.17

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Abstract

The present study aimed to determine the effects of mannoheptulose (MH) (8mg/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 (0mg/kg) or MH supplement and high CHO relative to fat diet (HC; 54 % CHO, 11 % fat) with placebo (0mg/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 (0-4h; 5-10h; 11-17h; 18-23h) EE and RQ were determined by indirect calorimetry (days 12 or 14). Glycaemic response to a meal (24h) 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 (5-10h 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.

Highlights

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)
Postprandial EE was not affected by diet, with the exception of the 5–10 h postprandial period (Table 2, online Supplementary Fig. 1(a))
While fasting RQ was not statistically significantly affected by diet, it was highest in dogs fed the high-carbohydrate diet with placebo supplement (HC)+MH diet (Table 2)

Summary

Introduction

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). Weight-loss diets achieve energy dilution by altering the macronutrient content of the diet These diets contain low fat and high carbohydrate (CHO) concentrations. Dogs given MH doses ranging 1–2 g/kg (intravenous or intra-arterial) exhibit a transient diabetic state, characterised by marked hyperglycaemia, dramatically decreased insulin:glucagon ratio and increased hepatic glucose output[14,15,16,17]. These responses were well outside normal physiological ranges, suggesting that the dosage was supraphysiological. The objective of the present study was to determine the effects of avocado-derived MH on glycaemic response, macronutrient oxidation and energy expenditure (EE) in adult Beagle dogs. Given MH’s known role as a glycolytic inhibitor, we expected MH to differentially affect these outcomes when fed in the presence of low or high dietary CHO concentrations

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