Status of selected nutrients in obese dogs undergoing caloric restriction

Effects of weight loss and feeding specially formulated diets on the body composition, blood metabolite profiles, voluntary physical activity, and fecal metabolites and microbiota of obese dogs

Canine obesity negatively influences health and well-being, but can be managed by altering diet composition and caloric intake. Restricted feeding, dietary intervention, and consequent weight loss may be used to improve health and modify gastrointestinal microbiota. In this study, we aimed to determine the effects of restricted feeding of specially formulated foods on weight loss, body composition, voluntary physical activity, serum hormones and oxidative stress markers, and fecal metabolites and microbiota populations of obese dogs. Twenty-four obese dogs [body weight (BW) = 15.2 ± 1.7 kg; body condition score (BCS) = 8.7 ± 0.4; muscle condition score (MCS) = 3.5 ± 0.3; age = 7.2 ± 1.6 yr] were used in a 24-wk study. A control (OR) food was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline, dogs were allotted to one of two diets: OR or test (FT), and then fed to lose 1.5% BW/wk. Food intake, BW, BCS, and MCS were measured, blood and fecal samples were collected, DEXA scans were performed, and voluntary physical activity was measured over time. Microbiota data were evaluated using QIIME2 and change from baseline data from other measures were evaluated using the Mixed Models procedure of SAS, with P < 0.05 being significant. Restricted feeding led to reduced BW, BCS, fat mass, and blood cholesterol, triglyceride, glucose, and leptin concentrations, and increased MCS and lean body mass percentage. Blood cholesterol reduction was greater in dogs fed FT vs. OR. Fecal metabolites and bacterial alpha-diversity were affected by diet and weight loss. Dogs fed FT had greater reductions in fecal short-chain fatty acid, branched-chain fatty acid, and ammonia concentrations than those fed OR. Dogs fed OR had a higher alpha-diversity than those fed FT. Weight loss increased alpha-diversity (weeks 16, 20, and 24 > weeks 0 and 4). Beta-diversity showed separation between dietary groups and between week 0 and all other time points after week 8. Weight loss increased fecal Allobaculum and Ruminococcus torques. Weight loss also increased fecal Bifidobacterium, Faecalibaculum, and Parasutterella, but were greater in dogs fed OR. Weight loss decreased fecal Collinsella, Turicibacter, Blautia, Ruminococcus gnavus, Faecalibacterium, and Peptoclostridium, but were greater in dogs fed OR. In summary, restricted feeding promoted safe weight and fat loss, reduced blood lipid and leptin concentrations, and altered fecal microbiota of obese dogs.

Evaluation of the nutrients supplied by veterinary diets commercialized in Brazil for obese dogs undergoing a weight loss program

During a weight loss program, energy restriction is performed, which can result in nutrient intake below the minimum recommendations if a proper diet is not offered. A common recommendation for dogs undergoing energy restriction is to use a veterinary diet formulated for the management of obesity to potentially reduce the likelihood of nutritional deficiencies. The objective of this study was to perform bromatological and essential mineral analysis in veterinary diets for the management of canine obesity available in the Brazilian market and to analyse whether these diets provide the recommended amount of nutrients per kg of metabolic body weight (kg BW^0.75 ) for animals undergoing energy restriction. Samples of all veterinary diets for the management of canine obesity available in the Brazilian pet food market were analysed (n = 8). The nutrient supply per kg BW^0.75 was calculated and compared with the NRC recommended allowance and FEDIAF recommendations by descriptive statistics. For this purpose, the weight loss energy requirement equations of 70 kcal/target body weight^0.75 and 63 kcal/target body weight^0.75 were used, in which target body weight corresponds to 10%-40% of the initial body weight according to the body condition score. The manufacturers' intake recommendations were also evaluated and compared to the NRC and FEDIAF recommendations. Almost all of the diets (n = 7/8) had at least one nutrient below the NRC and FEDIAF recommendations when target weight of minus 10%, 20% or 30% was considered, and all diets had at least one nutrient deficiency when the target weight was minus 40%. When the energy intake was restricted a further 10%, all diets had at least one nutrient below recommendations at the minus 30% target weight. The nutrients for which the recommendations were not met were as follows: calcium, magnesium, potassium, selenium, sodium, protein and fat. When compared to the manufacturers' recommendations, nutrient deficiencies were observed in all of the diets when compared to the NRC and in 7/8 when compared to FEDIAF, and all diets had at least one deficiency when compared to both NRC and FEDIAF after an extra 10% calorie restriction. It was concluded that the majority of veterinary diets formulated for weight loss/obesity management in Brazil did not meet all the recommendations of the analysed nutrients, which reinforces that diets for weight loss should be used according to veterinary prescription and should ideally be prescribed by nutrition specialists that can better understand the limitations of the diet's composition.

Weight-loss in obese dogs promotes important shifts in fecal microbiota profile to the extent of resembling microbiota of lean dogs

BACKGROUND

Among the undesirable changes associated with obesity, one possibility recently raised is dysbiosis of the intestinal microbiota. Studies have shown changes in microbiota in obese rats and humans, but there are still few studies that characterize and compare the fecal microbiota of lean, obese and dogs after weight loss. Thus, this study aimed to evaluate the effects of a weight loss program (WLP) in fecal microbiota of dogs in addition to comparing them with those of lean dogs. Twenty female dogs of different breeds, aged between 1 and 9 years were selected. They were equally divided into two groups: Obese group (OG), with body condition score (BCS) 8 or 9/9, and body fat percentage greater than 30%, determined by the deuterium isotope dilution method, and lean group (LG) with BCS 5/9, and maximum body fat of 15%. Weight loss group (WLG) was composed by OG after loss of 20% of their current body weight. Fecal samples were collected from the three experimental groups. Total DNA was extracted from the feces and these were sequenced by the Illumina methodology. The observed abundances were evaluated using a generalized linear model, considering binomial distribution and using the logit link function in SAS (p < 0.05).

RESULTS

The WLP modulated the microorganisms of the gastrointestinal tract, so that, WLG and LG had microbial composition with greater biodiversity than OG, and intestinal uniformity of the microbiota (Pielou's evenness index) was higher in OG than WLG dogs (P = 0.0493) and LG (P = 0.0101). In addition, WLG had values of relative frequency more similar to LG than to OG.

CONCLUSION

The fecal microbiota of the studied groups differs from each other. The weight loss program can help to reverse the changes observed in obese dogs.

Selenium and Dogs: A Systematic Review

The intent of this review is to summarize the knowledge about selenium and its function in a dog's body. For this purpose, systematic literature search was conducted. For mammals, including dogs, a balanced diet and sufficient intake of selenium are important for correct function of metabolism. As for selenium poisoning, there are no naturally occurring cases known. Nowadays, we do not encounter clinical signs of its deficiency either, but it can be subclinical. For now, the most reliable method of assessing selenium status of a dog is measuring serum or plasma levels. Levels in full blood can be measured too, but there are no reference values. The use of glutathione peroxidase as an indirect assay is questionable in canines. Commercial dog food manufactures follow recommendations for minimal and maximal selenium levels and so dogs fed commercial diets should have balanced intake of selenium. For dogs fed home-made diets, complex data are missing. However, subclinical deficiency seems to affect, for example, male fertility or recovery from parasitical diseases. Very interesting is the role of selenium in prevention and treatment of cancer.

Use of reduced-energy content maintenance diets for modest weight reduction in overweight cats and dogs

One option for controlled weight loss for dogs and cats in overweight condition could be to modestly restrict caloric intake using a reduced-energy ('light') maintenance diet, but there is no prior research on the safety and efficacy of such an approach. A prospective observational cohort study was performed in 67 overweight dogs and 17 overweight cats undergoing weight loss using reduced-energy maintenance diets from one manufacturer. Diets were fed at approximately 80% of maintenance energy requirements for ideal bodyweight for a period of 8 weeks. Essential nutrient intake was estimated for each dog and cat and compared with minimum requirement (MR) or adequate intake (AI, when no MR had been demonstrated) as set by the National Research Council in 2006. Weight loss was seen in 56/67 dogs (84%), losing a median of 4.7% (range 15.2% loss to 10.0% gain) of their starting body weight (SBW). Weight loss was also seen in all 17 cats, losing a median of 6.4% (range 2.0 loss to 15.2% loss) of SBW. Of the essential nutrients examined, only selenium, choline, potassium, and riboflavin were less than NRC recommendations in a minority of animals. However, no signs of any nutrient deficiency were observed in any of the dogs or cats during the study. In summary, modestly energy restricting overweight dogs and cats when feeding a low-energy maintenance diet can induce weight loss and might be a useful initial step for weight management. Although no adverse effects were seen, borderline intake of some micronutrients warrants further consideration.

Genome-wide association studies of 74 plasma metabolites of German shepherd dogs reveal two metabolites associated with genes encoding their enzymes

INTRODUCTION

German shepherd dogs (GSDs) are a popular breed affected by numerous disorders. Few studies have explored genetic variations that influence canine blood metabolite levels.

OBJECTIVES

To investigate genetic variants affecting the natural metabolite variation in GSDs.

METHODS

A total of 82 healthy GSDs were genotyped on the Illumina CanineHD Beadchip, assaying 173,650 markers. For each dog, 74 metabolites were measured through liquid and gas chromatography mass spectrometry (LC-MS and GC-MS) and were used as phenotypes for genome-wide association analyses (GWAS). Sliding window and homozygosity analyses were conducted to fine-map regions of interest, and to identify haplotypes and gene dosage effects.

RESULTS

Summary statistics for 74 metabolites in this population of GSDs are reported. Forty-one metabolites had significant associations at a false discovery rate of 0.05. Two associations were located around genes which encode for enzymes for the relevant metabolites: 4-hydroxyproline was significantly associated to D-amino acid oxidase (DAO), and threonine to L-threonine 3-dehydrogenase (LOC477365). Three of the top ten haplotypes associated to 4-hydroxyproline included at least one SNP on DAO. These haplotypes occurred only in dogs with the highest 15 measurements of 4-hydroxyproline, ranging in frequency from 16.67 to 20%. None of the dogs were homozygous for these haplotypes. The top two haplotypes associated to threonine included SNPs on LOC477365 and were also overrepresented in dogs with the highest 15 measurements of threonine. These haplotypes occurred at a frequency of 90%, with 80% of these dogs homozygous for the haplotypes. In dogs with the lowest 15 measurements of threonine, the haplotypes occurred at a frequency of 26.67% and 0% homozygosity.

CONCLUSION

DAO and LOC477365 were identified as candidate genes affecting the natural plasma concentration of 4-hydroxyproline and threonine, respectively. Further investigations are needed to validate the effects of the variants on these genes.

Dog owner's accuracy measuring different volumes of dry dog food using three different measuring devices

Prior research demonstrates significant inaccuracy when repeatedly measuring the same amount of dry dog food using a dry-food measuring cup, bringing into question the accuracy of measuring devices. This study aimed to determine dog owners’ accuracy when measuring different volumes of dry dog food using different types of measuring devices. One hundred dog owners, randomly assigned one of three measuring devices (a one-cup dry-food measuring cup, a two-cup graduated-liquid measuring cup or a two-cup commercial food scoop), were asked to measure ¼, ½ and 1 cup of dry dog food. Accuracy was assessed with an electronic gram scale by comparing measured volumes with the correct weight in grams. Individual accuracy ranged from −47.83% to 152.17% across devices and volumes. Measuring accuracy was found to be associated with the volume of food measured (p<0.001) and the type of measuring device used (p<0.001). Findings highlight approaches for decreasing excess intake of calories by dogs, including promotion of tactics to improve measurement accuracy (eg, gram scales, volume-calibrated dry-food measuring devices), especially for measuring small volumes.

Dietary Aspects of Weight Management in Cats and Dogs

The optimal weight loss diet for cats and dogs is best determined by obtaining a full dietary history and performing a detailed assessment of the pet, pet owner, and environment in which the pet lives. Incorporating information about pet and owner preferences allows for individualization of the weight management plan and has the potential to increase adherence. Calorie density, macronutrients, and micronutrient concentrations should be considered as part of a weight management plan. Owners should play an active role in the weight loss plan to have the best outcome.

Navy and black bean-based dog foods are digestible during weight loss in overweight and obese adult companion dogs

Common beans (Phaseolus vulgarisL.) are a nutrient-dense, low glycemic index food that supports healthy weight management in people and was examined for dogs. The objectives of this study were to evaluate the apparent total tract digestibility (ATTD) and nutrient utilisation of navy (NB) and black (BB) bean-based diets in overweight or obese companion dogs undergoing a weight loss intervention. A nutritionally complete, dry extruded dog food was used as the control (CON) diet and two isocaloric, nutrient matched bean diets, containing either 25% w/w cooked BB or NB powder formed the test diets. Diets were fed to adult, overweight companion dogs for either four weeks (short-term study, n = 30) or for twenty-six weeks (long-term study, n = 15) at 60% of maintenance calories for ideal weight. Apparent weight loss increased over time in both the short- and long-term studies (p < 0.001) but was not different between the three study groups: apparent weight loss was between 4.05% – 6.14% for the short-term study and 14.0% – 17.9% in the long-term study. The ATTD was within expected ranges for all groups, whereby total dry matter and crude protein ATTD was 7–8% higher in the BB diet compared to CON (P < 0.05), crude fat ATTD was similar across all diets, and nitrogen free extract ATTD was 5–6% higher in both BB and NB compared to CON (P < 0.05). Metabolisable energy was similar for all diets, and ranged from 3,434–3,632 kcal/kg. At the end of each study period, dogs had haemoglobin levels ≥12 g/dl, packed cell volume ≥36%, albumin ≥2.4 g/dl, ALP ≤ 300 IU/l and all median values for each group were within defined limits for nutritional adequacy. This investigation demonstrated that BB and NB diets were safe, digestible, and supported weight loss in calorically restricted, overweight or obese, adult companion dogs.

Assessing the adequacy of essential nutrient intake in obese dogs undergoing energy restriction for weight loss: a cohort study

Background

Canine obesity is usually treated with dietary energy restriction, but data are limited regarding nutritional adequacy. The aim of the current study was to compare intake of essential nutrients with National Research Council recommendations in obese dogs during weight management with a purpose-formulated diet.

Methods

Twenty-seven dogs were included in this non-randomised retrospective observational cohort study. All were determined to be systemically well, and without significant abnormalities based upon physical examination and clinicopathological assessments. The dogs underwent a controlled weight loss protocol of at least 182 days’ duration using a high protein high fibre weight loss diet. Median, maximum, and minimum daily intakes of all essential nutrients were compared against NRC 2006 recommended allowances (RA) for adult dogs.

Results

Median weight loss was 28 % (16–40 %), mean daily energy intake was 61 kcal/kg^0.75 (44–74 kcal/kg^0.75), and no clinical signs of nutrient deficiency were observed in any dog. Based upon the average nutrient content of the diet, daily intake of the majority of essential nutrients was greater than their NRC 2006 recommended allowance (RA per kg body weight^0.75), except for selenium, choline, methionine/cysteine, tryptophan, magnesium, and potassium. However, apart from choline (2/27 dogs) and methionine/cysteine (2/27 dogs), all essential nutrients remained above NRC minimum requirements (MR) throughout the trial.

Conclusions

When fed the diet used in the current study, daily intakes of most essential nutrients meet both their NRC 2006 RA and MR in obese dogs during weight loss. In light of absence of clinical signs of nutrient deficiency, it is unclear what significance intakes less that NRC cut-offs for some nutrients have (especially selenium and choline), and further studies are recommended.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0570-y) contains supplementary material, which is available to authorized users.

Canine and feline obesity: a review of pathophysiology, epidemiology, and clinical management

Canine and feline obesity rates have reached pandemic proportions and are similar to those in humans, with approximately 30%-40% of dogs and cats being overweight to obese. Obesity has been associated with other health problems, including osteoarthritis, renal disease, skin disease, insulin resistance, and neoplasia in dogs, while in cats obesity is associated with dermatological issues, diabetes mellitus, neoplasia, and urolithiasis. The health issues appear to be slightly different across the two species, which may be due to some inherent differences in the hormonal milieu involved in obesity that differs between the dog and the cat. In this review, we discuss the complicated nature of the pathogenesis of obesity, the hormonal stimulus for orexigenic and anorexigenic behavior, adipose tissue as an endocrine organ, and most importantly, clinical management of the number one disease in canine and feline medicine.

Pet obesity management: beyond nutrition

Excess weight has been associated with many clinical and subclinical conditions that put a pet's health at risk. Successful weight management programs extend beyond standard nutritional management and incorporate an understanding of human-animal interaction. Understanding the processes and dynamics of human-animal relationships can be a useful tool for practitioners in developing successful treatment plans for their clients. Obesity is a nutritional disorder requiring lifelong management; however, when veterinarians go beyond standard treatment to include an understanding of human-animal interaction, it is also one of the few conditions in veterinary medicine that is completely preventable and curable.