Gonadectomy and high dietary fat but not high dietary carbohydrate induce gains in body weight and fat of domestic cats

Abstract

A high concentration of dietary carbohydrate is suggested to increase the risk of obesity and diabetes mellitus in domestic cats. To evaluate this, food intake, body weight, fat mass and circulating adiposity-related factors were determined in twenty-four sexually mature (9-12 months) cats assigned to four six-cat dietary groups balanced for body weight and sex. The effect of dietary fat in exchange for carbohydrate at 9, 25, 44 and 64 % of metabolisable energy (ME) in a purified diet of constant protein:ME ratio was studied 13 weeks before and 17 weeks after gonadectomy (GX). Body weight did not significantly change among the cats before GX except for an increase of 17 (SEM 5) % in cats given the highest-fat diet. Following GX, all groups gained body weight, and body fat mass was positively correlated (r 0·50; P,0·04) with dietary fat percentage. Post-GX weight gains were much greater for females (þ39 (SEM 5) %) than males (þ 10 (SEM 4) %). Plasma ghrelin concentration negatively correlated (P,0·02) with dietary fat percentage and, before GX, was greater (P, 0·05) in females than males. Plasma insulin concentration increased with weight gain induced by high dietary fat. Plasma glucose, TAG and leptin concentrations were not affected by dietary fat percentage, GX or weight gain. These data provide evidence that in cats, high dietary fat, but not carbohydrate, induces weight gain and a congruent increase in insulin, while GX increases sensitivity to weight gain induced by dietary fat. Obesity: Dietary fat: Neutering: Ghrelin: CatsAn evaluation of the nutrient requirements of domestic cats has led to the conclusion that cats are metabolically attuned to carnivorous diets 1 . As such, cats serve as useful models for studies of comparative nutrition and metabolism. Recent epidemiological investigations have yielded evidence which attributes an increased risk for obesity in cats to commercially available, high-carbohydrate, dry-expanded diets as opposed to commercially available, canned, high-fat diets 2 . These observations in cats deviate from experimental finding in the rodent literature, where diets high in fat are found to cause weight gain and induce obesity 3,4 . Mechanisms by which high-carbohydrate diets might cause obesity in cats are speculative. A high constitutive rate of glucose production from amino acid catabolism and a low capacity for glucose disposal are suggested to direct unutilised carbohydrate toward fatty acid synthesis and storage 5 . An alternative mechanism is that high dietary carbohydrate exposure extraordinarily prolongs insulin release, resulting in diversion of dietary fat away from oxidation toward storage in adipose. This latter mechanism seems more plausible than the former because feline liver and adipose tissues appear to poorly utilise glucose for fatty acid synthesis 6 . Ingredients, energy density and palatability of high-carbohydrate, commercial dry-expanded diets are substantively different from those in most commercial canned diets. Because of this, factors other than carboh...

Ovariohysterectomy alters body composition and adipose and skeletal muscle gene expression in cats fed a high-protein or moderate-protein diet

“…Food intake and BW increased in all cats following ovariohysterectomy, as has been noted in other studies (Fettman et al, 1997;Harper et al, 2001;Kanchuk et al, 2003;Nguyen et al, 2004;Backus et al, 2007;Cave et al, 2007;Belsito et al, 2009). Earlier research has indicated that an estimated 20% to 30% reduction in food intake is needed to maintain BW of neutered cats (Flynn et al, 1996;Root et al, 1996;Belsito et al, 2009).…”

Feline obesity - prevalence, risk factors, pathogenesis, associated conditions and assessment: a review

“…When 22 shorthair adult female cats were fed at maintenance energy requirements for intact cats before and after ovariohysterectomy, all the cats increased body weight by 16% and BCS by one point after ovariohysterectomy (Mitsuhashi et al 2011). Several studies in cats have also reported a significant increase in food intake after neutering, which leads to weight gain and decreased physical activity (Fettman et al 1998;Kanchuk et al 2003;Backus et al 2007;Belsito et al 2009). …”

Impact of Commercially Available Diabetic Prescription Diets on Short-Term Postprandial Serum Glucose, Insulin, Triglyceride and Free Fatty Acid Concentrations of Obese Cats

“…The authors speculated that fatty acid may be used as a substitute for glucose to supply energy in high-fat diets. However, another study demonstrated that plasma concentrations of insulin in cats given the highest-fat diet were greater than those of cats given lower-fat diets [4]. The M/D dry diet (highest fat content in the present study) did not induce postprandial hyperglycemia or any apparent insulin secretion, leading us to speculate that dietary fat content has less impact and effect on postprandial glucose and insulin concentration, as compared with dietary carbohydrate and fiber content in the present study.…”

“…However, according to previous studies, low-carbohydrate diets may also aid glycemic control in Type 2 DM by reducing hyperglycemia and aiding in recovery from glucose toxicity [1,13,27]. Several studies have employed a test meal, for evaluating postprandial glucose concentrations, insulin concentrations or changes in body weight [4,19,20,37]. However, information on the effects of the use of commercially available prescription diets to manage feline obesity is scarce and thus far includes only two studies that have investigated the effects of these diets on glucose and insulin concentrations in cats [8,26].…”