Effect of Weight Loss in Obese Dogs on Indicators of Renal Function or Disease

Environmental risk factors in puppies and kittens for developing chronic disorders in adulthood: A call for research on developmental programming

Many dogs and cats are affected by chronic diseases that significantly impact their health and welfare and relationships with humans. Some of these diseases can be challenging to treat, and a better understanding of early-life risk factors for diseases occurring in adulthood is key to improving preventive veterinary care and husbandry practices. This article reviews early-life risk factors for obesity and chronic enteropathy, and for chronic behavioral problems, which can also be intractable with life-changing consequences. Aspects of early life in puppies and kittens that can impact the risk of adult disorders include maternal nutrition, establishment of the gut microbiome, maternal behavior, weaning, nutrition during growth, growth rate, socialization with conspecifics and humans, rehoming and neutering. Despite evidence in some species that the disorders reviewed here reflect the developmental origins of health and disease (DOHaD), developmental programming has rarely been studied in dogs and cats. Priorities and strategies to increase knowledge of early-life risk factors and DOHaD in dogs and cats are discussed. Critical windows of development are proposed: preconception, gestation, the suckling period, early growth pre-neutering or pre-puberty, and growth post-neutering or post-puberty to adult size, the durations of which depend upon species and breed. Challenges to DOHaD research in these species include a large number of breeds with wide genetic and phenotypic variability, and the existence of many mixed-breed individuals. Moreover, difficulties in conducting prospective lifelong cohort studies are exacerbated by discontinuity in pet husbandry between breeders and subsequent owners, and by the dispersed nature of pet ownership.

Untargeted fecal metabolome analysis in obese dogs after weight loss achieved by feeding a high-fiber-high-protein diet

INTRODUCTION

In humans and companion animals, obesity is accompanied by metabolic derangements. Studies have revealed differences in the composition of the fecal microbiome between obese dogs and those with an ideal body weight.

OBJECTIVES

We have previously reported that the fecal microbiome in obese dogs changes after controlled weight reduction, induced by feeding a diet high in fiber and protein. Despite these findings, it is unclear if taxonomic differences infer differences at the functional level between obese dogs and those with an ideal body weight.

METHODOLOGY

Untargeted fecal metabolome analysis was performed on dogs with obesity before and after weight loss achieved by feeding a high-fiber-high-protein diet.

RESULTS

Fecal metabolome analysis revealed a total of 13 compounds that changed in concentration in obese dogs after weight loss. Of these compounds, metabolites associated with bacterial metabolism decreased after weight loss including purine, L-(-)-methionine, coumestrol, and the alkaloids 1-methylxanthine and trigonelline. Conversely, the polyphenols (-)-epicatechin and matairesinol and the quinoline derivatives 1,5-isoquinolinediol and 2-hydroxiquinoline increased after weight loss.

CONCLUSION

These results suggest differences in intestinal microbiome at the functional level after weight loss, but further studies are needed to determine the role of these compounds in the etiology of obesity and weight loss.

Kidney function and glucose metabolism in overweight and obese cats

Background: In people, obesity and prediabetes mellitus might predispose to chronic kidney disease (CKD).Aims: To assess the association of overweight [Body condition score (BCS) >5] and glucose metabolism alterations, with established or potential markers of CKD. In addition, fructosamine and fasted blood glucose were compared as predictors of early abnormal glucose metabolism.Methods: 54 clinically healthy cats were included in a cross-sectional study comprising 25 neutered males and 29 (28 neutered) females aged 7.2 (5.5-9.4) years. Two potential markers of CKD, namely urinary free active transforming growth factor-β1-creatinine ratio and urinary retinol binding protein-creatinine ratio were measured along with other parameters to assess CKD. A receiver operating curve was used to identify the best sensitivity and specificity of fructosamine to identify cats with fasting glucose >6.5 mmol/L.Results: No association was found between BCS and markers of CKD. Fructosamine was greater in cats with fasting glucose >6.5 mmol/L compared to those with fasting glucose ≤6.5 mmol/L. A fructosamine concentration ≥250 µmol/L was able to detect cats with hyperglycemia with a sensitivity of 77% and a specificity of 65%. Furthermore, fructosamine was more strongly correlated with fasting glucose than albumin-corrected fructosamine (r = 0.43, p = 0.002 vs r = 0.32, p = 0.026). Cats with higher fructosamine had lower serum symmetric dimethylarginine concentrations.Conclusion: The present study does not suggest an effect of obesity on renal function in domestic cats.Clinical relevance: Fructosamine might be of value for the diagnosis of prediabetes mellitus in cats.

Serum cystatin C concentration can be used to evaluate glomerular filtration rate in small dogs

Serum cystatin C levels (CysC) are used in human medicine to document progressive kidney failure. Although CysC are not thought to be useful for the diagnosis of kidney dysfunction in dogs, there has been no specific consideration of body weight as a confounding issue. The aim of this study was to assess that the utility of CysC for the diagnosis of decreased glomerular filtration rate (GFR) in smaller vs. larger dogs. In clinically healthy dogs, serum creatinine (Cre) and CysC correlate directly with body weight; we found that dogs weighing <20 kg had significantly lower CysC than those weighing ≥20 kg (0.27 ± 0.07 vs. 0.34 ± 0.05 mg/l, respectively, P<0.001). In dogs weighing <20 kg, CysC had superior diagnostic accuracy for the detection of mildly decreased plasma iohexol clearance (PCio) (<1.8 ml/min/kg) compared with Cre (sensitivity 100% vs. 80.9% and specificity 100% vs. 85.7%); this was not true for dogs weighing ≥20 kg. Additionally, using a cut-off PCio of <1.8 ml/min/kg, the area under receiver-operating characteristics curve (AUC) of CysC was significantly higher than that of Cre in dogs weighing <20 kg (P<0.05); this was not true for dogs weighing ≥20 kg (P=0.695). In conclusion, CysC is a useful marker for the detection of a mild decreasing GFR compared with Cre in dogs weighing <20 kg.

Effect of a Weight Loss Program on Biochemical and Immunological Profile, Serum Leptin Levels, and Cardiovascular Parameters in Obese Dogs

This study aimed to investigate the effects of a weight loss program (WLP) on biochemical and immunological profile, and cardiovascular parameters in a cohort of dogs with naturally occurring obesity. Eleven obese dogs [body condition scoring (BCS), ≥7/9] were enrolled into the study and underwent clinical and cardiovascular examination, and blood testing before (T0) and after 6 months (T1) of WLP. Eleven normal weight (BCS, 4/5) healthy dogs were used as a control (CTR) group. Compared to the CTR group, at T0 obese dogs expressed higher serum leptin concentrations (p < 0.0005) that significantly decreased after weight loss (p < 0.005) but remained higher than the CTR group. Furthermore, obese dogs showed considerably lower levels (p < 0.0005) of regulatory T cell (Treg) compared to the CTR group, but they did not change after weight loss at T1. In obese dogs, tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations were substantially reduced at T1 (p < 0.0001 and p < 0.005). Regarding the cardiovascular parameters, only one obese dog was hypertensive at T0, and systolic blood pressure values showed no significant differences at the end of the WLP. The ratio of interventricular septal thickness in diastole to left ventricle internal diameter in diastole (IVSd/LVIDd) was significantly greater in obese dogs at T0 than in the CTR group (p < 0.005). It decreased after weight loss (p < 0.05). In obese dogs, troponin I level significantly reduced with weight loss (p < 0.05), while endothelin-1 level did not differ statistically. The results suggest that the immune dysregulation in the presence of high leptin levels and reduced number of Treg could affect obese dogs as well as humans. Based on our findings, we may speculate that a more complete immune-regulation restore could be obtained by a greater reduction in fat mass and a longer-term WLP. Finally, left ventricular remodeling may occur in some obese dogs. However, in canine species, further studies are needed to investigate the impact of obesity and related WLP on cardiovascular system.

Changes in the salivary proteome of beagle dogs after weight loss

Being overweight or obese represents an important health issue in humans and pets. The aim of this study was to investigate changes in the salivary proteome of overweight beagles after induced weight loss to better understand the physiological changes involved in this process. Five overweight/obese neutered males of pure breed beagles were evaluated. During the 3-mo period of weight loss, each animal received a strictly controlled amount of a low fat commercial diet per day. Body condition scores (BCS), body weight (BW), and serum biochemical parameters (total cholesterol, triglycerides, and C-reactive protein) were assessed weekly. Quantitative proteomics analysis by SWATH was used to evaluate the salivary proteome changes induced by weight loss treatment. BCS, BW, serum total cholesterol concentration, and abundances of 23 salivary proteins differed significantly between before and after treatment. Some of the altered protein amounts, namely of peptidyl-prolyl cis-trans isomerase, fructose-bisphosphate aldolase C, and 78-kDa glucose-regulated protein, increased after weight loss. These proteins are related with the immune system, inflammatory status, oxidative stress, and glucose metabolism. The results obtained suggest a potential use of salivary proteins in monitoring physiological changes in dogs subjected to weight loss. Moreover, the type of changes identified reinforces the postulated physiological improvements, which weight loss induces. Further research is needed to determine whether the changes observed in this study are due to weight loss, dietary changes, or a combination of both.

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.

Weight-gain induced changes in renal perfusion assessed by contrast-enhanced ultrasound precede increases in urinary protein excretion suggestive of glomerular and tubular injury and normalize after weight-loss in dogs

Early detection of obesity-related glomerulopathy in humans is challenging as it might not be detected by routine biomarkers of kidney function. This study's aim was to use novel kidney biomarkers and contrast-enhanced ultrasound (CEUS) to evaluate the effect of obesity development and weight-loss on kidney function, perfusion, and injury in dogs. Sixteen healthy lean adult beagles were assigned randomly but age-matched to a control group (CG) (n = 8) fed to maintain a lean body weight (BW) for 83 weeks; or to a weight-change group (WCG) (n = 8) fed the same diet to induce obesity (week 0-47), to maintain stable obese weight (week 47-56) and to lose BW (week 56-83). At 8 time points, values of systolic blood pressure (sBP); serum creatinine (sCr); blood urea nitrogen (BUN); serum cystatin C (sCysC); urine protein-to-creatinine ratio (UPC); and urinary biomarkers of glomerular and tubular injury were measured. Glomerular filtration rate (GFR) and renal perfusion using CEUS were assayed (except for week 68). For CEUS, intensity- and time-related parameters representing blood volume and velocity were derived from imaging data, respectively. At 12-22% weight-gain, cortical time-to-peak, representing blood velocity, was shorter in the WCG vs. the CG. After 37% weight-gain, sCysC, UPC, glomerular and tubular biomarkers of injury, urinary immunoglobulin G and urinary neutrophil gelatinase-associated lipocalin, respectively, were higher in the WCG. sBP, sCr, BUN and GFR were not significantly different. After 23% weight-loss, all alterations were attenuated. Early weight-gain in dogs induced renal perfusion changes measured with CEUS, without hyperfiltration, preceding increased urinary protein excretion with potential glomerular and tubular injury. The combined use of routine biomarkers of kidney function, CEUS and site-specific urinary biomarkers might be valuable in assessing kidney health of individuals at risk for obesity-related glomerulopathy in a non-invasive manner.

Animal Models and Renal Biomarkers of Diabetic Nephropathy

Diabetes mellitus (DM) is the first cause of end stage chronic kidney disease (CKD). Animal models of the disease can shed light on the pathogenesis of the diabetic nephropathy (DN) and novel and earlier biomarkers of the condition may help to improve diagnosis and prognosis. This review summarizes the most important features of animal models used in the study of DN and updates the most recent progress in biomarker research.

Evaluation of nephrotoxicity and ototoxicity of aminosidine (paromomycin)-allopurinol combination in dogs with leishmaniosis due to Leishmania infantum: A randomized, blinded, controlled study

Canine leishmaniosis due to Leishmania infantum is a widespread zoonotic disease. Although aminosidine can be an effective treatment, current therapeutic recommendations do not advocate its use, mainly due to concerns regarding the potential nephrotoxicity and ototoxicity of this drug. The aim of this randomized, blinded, controlled study was to evaluate the nephrotoxicity and ototoxicity of aminosidine-allopurinol combination and compare it with that of meglumine antimonate-allopurinol combination in non-azotemic dogs with leishmaniosis. Forty dogs with leishmaniosis were randomly assigned to be treated with either aminosidine at 15 mg/kg, subcutaneously, once daily for 28 days (group A) or with meglumine antimonate at 100 mg/kg, subcutaneously, once daily for 28 days (group B). In addition to either drug, dogs in both groups were administered allopurinol at 10 mg/kg per os twice daily for 2 months. Kidney function was evaluated through measurement of serum creatinine, urea nitrogen, inorganic phosphorus, and cystatin-c concentrations and complete urinalysis, including protein-to-creatinine ratio, at baseline and after 14, 28, and 60 days from the beginning of the treatment. At the same time points, vestibular and auditory functions were evaluated through neurological examination and brainstem auditory evoked response (BAER) recordings of wave I, wave V, inter-wave I-V latencies, and minimum hearing thresholds. None of the dogs developed clinicopathological evidence of kidney disease during the study. Serum creatinine concentration increased >0.3 mg/dl over baseline in 2 dogs in group A and in 5 dogs in group B. Parameters of kidney function were not significantly different or were improved compared to baseline and the only difference between the two groups was the lower concentration of serum creatinine in group A. None of the dogs developed peripheral vestibular syndrome or hearing impairment. At the end of the study, parameters of auditory function were not significantly different or were improved compared to baseline and there were no differences between the two groups. The results of this study show that the nephrotoxicity and ototoxicity of aminosidine, when administered to non-azotemic dogs with leishmaniosis at 15 mg/kg subcutaneously once daily for 28 days along with allopurinol, is minimal and does not differ from that of meglumine antimonate.

Association between life span and body condition in neutered client-owned dogs

Background

There is an association between overweight status and life span in kenneled dogs, but a similar association has not been reported for pet dogs.

Objectives

To examine the effects of being overweight in middle age on the life span of neutered client‐owned dogs.

Animals

Fifty‐thousand seven‐hundred eighty seven middle‐aged neutered client‐owned dogs attending a network of approximately 900 veterinary hospitals across North America.

Methods

Retrospective case‐control study. For each of 12 breeds, groups of dogs aged between 6.5 and 8.5 years were identified as being in “overweight” or “normal” body condition. Within each breed and sex, differences in life span between dogs in normal body condition and overweight body condition in the 2 groups were then analyzed by Cox proportional hazards models.

Results

For all breeds, instantaneous risk of death for dogs in overweight body condition was greater than those in normal body condition throughout the age range studied, with hazard ratios ranging from 1.35 (99.79% confidence interval [CI] 1.05‐1.73) for German Shepherd dog to 2.86 (99.79% CI 2.14‐3.83) for Yorkshire Terrier. In all breeds, median life span was shorter in overweight compared with normal weight dogs, with the difference being greatest in Yorkshire Terriers (overweight: 13.7 years, 99.79% CI 13.3‐14.2; normal: 16.2 years, 99.79% CI 15.7‐16.5) and least in German Shepherd dogs (overweight: 12.1 years, 99.79% CI 11.8‐12.4; normal: 12.5 years, 99.79% CI 12.2‐12.9).

Conclusions and Clinical Importance

Veterinary professionals should consider promoting healthy body condition for dogs, particularly from midlife onward.

An open-label randomised clinical trial to compare the efficacy of dietary caloric restriction and physical activity for weight loss in overweight pet dogs

Canine obesity is usually managed with a combination of dietary caloric restriction and increasing physical activity, but no previous study has compared both of these strategies in a prospective randomised controlled trial. Thirteen overweight dogs (body condition score 6-9/9) were randomised to one of two interventions: dietary caloric restriction or physical activity. The dietary caloric restriction intervention comprised feeding a therapeutic weight loss diet, while the physical activity intervention comprised increasing the dog's current physical activity pattern by at least a third. The primary outcome measure was change in body weight, while secondary outcome measures included change in neck, thorax and abdominal circumference and change in physical activity measured by triaxial accelerometer. Bodyweight decreased significantly with the dietary caloric restriction (median -10% of starting body weight [SBW], 5 to -12%; P=0.028) but not with the physical activity intervention (-2% SBW, +3% to -6%; P=0.107). Abdominal circumference (dietary caloric restriction: median -12.0%; physical activity: median -7.8%, P=0.016) and thoracic circumference (dietary caloric restriction: median -7.5%, P=0.031; physical activity: median -3.6%, P=0.031) changed significantly in both groups. There was no change in activity levels within the dietary caloric restriction group, but vigorous activity increased significantly in the physical activity group (P=0.016). Dietary caloric restriction was more effective than physical activity for controlled weight loss in overweight pet dogs. Although advising owners to increase their dog's activity by a third led to a modest increase in measured vigorous physical activity, this was insufficient to promote weight loss on its own.

Success of a weight loss plan for overweight dogs: The results of an international weight loss study

INTRODUCTION

Obesity is a global concern in dogs with an increasing prevalence, and effective weight loss solutions are required that work in different geographical regions. The main objective was to conduct an international, multi-centre, weight loss trial to determine the efficacy of a dietary weight loss intervention in obese pet dogs.

METHODS

A 3-month prospective observational cohort study of weight loss in 926 overweight dogs was conducted at 340 veterinary practices in 27 countries. Commercially available dry or wet weight loss diets were used, with the initial energy allocation being 250-335 kJ/kg target body weight0.75/day (60-80 kcal/kg target body weight0.75/day) depending on sex and neuter status. The primary outcome measure was percentage weight loss; the main secondary outcomes were changes in activity, quality of life, and food-seeking behaviour, which were subjectively determined from owner descriptions.

RESULTS

At baseline, median (range) age was 74 (12 to 193) months and median body condition score was 8 (range 7-9). 896 of the 926 dogs (97%) lost weight, with mean weight loss being 11.4 ±5.84%. Sexually intact dogs lost more weight than neutered dogs (P = 0.001), whilst female dogs lost more weight than male dogs (P = 0.007), with the difference being more pronounced in North and South American dogs (median [Q1, Q3]: female: 11.5% [8.5%, 14.5%]; male: 9.1% [6.3%, 12.1%], P = 0.053) compared with those from Europe (female: 12.3% [8.9%, 14.9%]; male: 10.9% [8.6%, 15.4%]). Finally, subjective scores for activity (P<0.001) and quality of life (P<0.001) increased sequentially, whilst scores for food-seeking behaviour decreased sequentially (P<0.001) during the study.

CONCLUSION

This is the largest international multi-centre weight loss study conducted to date in obese dogs. Most dogs lost a clinically significant amount of weight, although there were notable differences between dogs of different sex, neuter status and in different geographical locations.

The Financial Costs, Behaviour and Psychology of Obesity: A One Health Analysis

People who are overweight or have obesity are estimated to comprise 30% of the global population and up to 59% of companion dogs and cats are estimated to be above their optimal body weight. The prevalence of human and companion obesity is increasing. The direct and indirect costs of obesity and associated comorbidities are significant for human and veterinary healthcare. There are numerous similarities between obesity in people and companion animals, likely related to the shared environmental and lifestyle elements of this multifactorial disease. While the study of human obesity is relatively robust, research conducted in pets is generally limited to small studies, studies with cross-sectional designs or reports that have yet to be replicated. Greater understanding of human obesity may elucidate some of the factors driving the more recent rise in pet obesity. In particular, there are overlapping features of obesity in children and pets that are, in part, related to dependency on their 'parents' for care and feeding. When feeding is used in a coercive and controlling fashion, it may lead to undesirable feeding behaviour and increase the risk for obesity. A 'responsive parenting' intervention teaches parents to respond appropriately to hunger-satiety cues and to recognize and respond to others' distress. Such interventions may impact on childhood overweight and obesity and have the potential to be adapted for use with companion animals. Social behaviour towards people with obesity or owners of pets with obesity is often driven by beliefs about the cause of the obesity. Educating healthcare professionals and the public about the multifactorial nature of this complex disease process is a fundamental step in reducing the bias and stigma associated with obesity. Children living in low-income households have particularly high rates of obesity and as household income falls, rates of obesity also rise in pets and their owners. There are risk regulators (i.e. dynamic components of interconnected systems that influence obesity-related behaviours) and internal factors (i.e. biological determinants of obesity) that may influence the development of both childhood and pet obesity, and poverty may intersect with these variables to exacerbate obesity in low-income environments. This review discusses the costs, behaviours and psychology related to obesity in people and pets, and also proposes potential techniques that can be considered for prevention and treatment of this disease in pets. A 'One Health' approach to obesity suggests that an understanding of human obesity may elucidate some of the factors driving the more recent rise in pet obesity.

Overweight dogs exercise less frequently and for shorter periods: results of a large online survey of dog owners from the UK

Canine obesity is now the number one health concern in dogs worldwide. Regular physical activity can improve health, and owners are advised to exercise their dogs on a regular basis. However, limited information exists about associations between overweight status of dogs and walking activity. An online survey was conducted between June and August in 2014, coinciding with the broadcast of a national UK television programme, exploring dog behaviour. Information gathered included signalment, overweight status, and owner-reported information on duration and frequency of dog walking. The University of Liverpool Ethics Committee approved the project, and owners consented to data use. Simple and multiple logistic regression analyses were used to determine associations between overweight status and dog walking activity. Data were available from 11 154 adult dogs, and 1801 (16·1 %) of these were reported as overweight by their owners. Dogs reported to be overweight dogs were more likely to be neutered (P < 0·0001) and older (P < 0·0001). Various breeds were over-represented including beagle, Cavalier King Charles spaniel, golden retriever, Labrador retriever and pug (P < 0·0001 for all). Both frequency and duration of walking were negatively associated with overweight status (P < 0·0001 for both). On multiple regression analysis, duration and frequency were independently and negatively associated with the odds of being overweight, along with a range of other factors including age, neuter status and breed. This study has identified associations between overweight status and exercise. In the future, studies should determine the reason for this association, and whether changes in walking activity can influence weight status.

Proteinuria in Apparently Healthy Elderly Dogs: Persistency and Comparison Between Free Catch and Cystocentesis Urine

BACKGROUND

Up to 25% of elderly humans have proteinuria, often associated with underlying lesions. Data concerning the presence of proteinuria in elderly dogs is scarce.

OBJECTIVES

To describe the presence and persistence of proteinuria and to compare urinary protein : creatinine ratio (UPC) between free catch and cystocentesis urine samples in apparently healthy elderly dogs.

ANIMALS

Hundred apparently healthy elderly dogs.

METHODS

Prospective study. Owners of 100 elderly dogs were asked to collect 2 free catch urine samples. Dogs were considered healthy based on owner's perception and an age chart, based on ideal bodyweight, was used to define dogs as senior or geriatric. UPC of urine collected by free catch and cystocentesis were compared. Overt proteinuria and borderline proteinuria were defined as UPC >0.5 and between 0.2 and 0.5, respectively, if examination of sediment did not explain proteinuria. Proteinuria was considered persistent if present at both sampling times.

RESULTS

At baseline, 71 owners succeeded in collecting urine. Eleven percent of dogs had overt proteinuria, 14% were borderline proteinuric, and 75% nonproteinuric. Thirty-seven repeated urine samples, with a median time interval of 31 days (range 10-90), were available. Nineteen percent of dogs had a persistently increased UPC (>0.2), with persistent overt proteinuria present in 8%. A strong correlation (ρ = 0.88) was found between UPC of urine collected by free catch and cystocentesis.

CONCLUSIONS AND CLINICAL IMPORTANCE

As 19% of study dogs had persistent proteinuria, our findings emphasize that measurement of proteinuria should be part of geriatric health screening. For UPC in dogs, free catch urine provides a good alternative to cystocentesis.

Comparison of voluntary food intake and palatability of commercial weight loss diets in healthy dogs and cats

Background

Obesity in dogs and cats is usually managed by dietary energy restriction using a purpose-formulated weight loss diet, but signs of hunger and begging commonly occur causing poor owner compliance. Altering diet characteristics so as to reduce voluntary food intake (VFI) can improve the likelihood of success, although this should not be at the expense of palatability. The aim of the current study was to compare the VFI and palatibility of novel commercially available canine and feline weight loss diets.

Methods

The relative performance of two canine (C1 and C2) and two feline (F1 and F2) diets was assessed in groups of healthy adult dogs and cats, respectively. Diets varied in energy, protein, fibre, and fat content. To assess canine VFI, 12 (study 1) and 10 (study 2) dogs were offered food in 4 meals, for 15 min on each occasion, with hourly intervals between the meals. For feline VFI, 12 cats were offered food ad libitum for a period of 18 h per day over 5 consecutive days. The palatability studies used separate panels of 37 dogs and 30 cats, with the two diets being served, side-by-side, in identical bowls.

Results

In dogs, VFI was significantly less for diet C1 than diet C2 when assessed on energy intake (study 1, 42% less, P = 0.032; study 2, 28% less, P = 0.019), but there was no difference in gram weight intake (study 1: P = 0.964; study 2: P = 0.255). In cats, VFI was 17% less for diet F1 than diet F2 when assessed by energy intake (P < 0.001), but there was again no difference in gram weight (P = 0.207). There was no difference in palatability between the two canine diets (P = 0.490), whilst the panel of cats diet preferred F1 to F2 (P < 0.001).

Conclusion

Foods with different characteristics can decrease VFI without affecting palatability in both dogs and cats. The effects seen could be due to decreased energy content, decreased fat content, increased fibre content, different fibre source, and increased protein content. Further studies are now needed to determine whether similar findings occur in obese dogs and cats on controlled weight loss programmes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0899-x) contains supplementary material, which is available to authorized users.

Weight management in obese pets: the tailoring concept and how it can improve results

Obesity is now recognised as the most important medical disease in pets worldwide. All current strategies for weight management involve dietary energy restriction with a purpose-formulated diet. Whilst current weight management regimes can be successful, outcomes are often disappointing with the rate of weight loss progressively slowing down as time goes on. Success is most challenging for the most obese dogs and cats that are more likely to discontinue the programme before reaching target weight. To improve outcomes, clinicians must focus carefully on better tailoring programmes, paying particular to setting an appropriate target weight so as to maximise the benefits for the individual. In this opinionated review, the author will discuss findings from recent clinical research studies examining weight management in obese dogs and cats. A strategy for tailoring weight management targets will then be discussed, illustrated with case examples.

A mixed grape and blueberry extract is safe for dogs to consume

Background

Grape and blueberry extracts are known to protect against age-related cognitive decline. However, beneficial effects achieved by mixing grape and blueberry extracts have yet to be evaluated in dogs, or their bioavailability assessed. Of concern to us were cases of acute renal failure in dogs, after their ingestion of grapes or raisins. The European Pet Food Industry Federation (2013) considers only the grape or raisin itself to be potentially dangerous; grape-seed extracts per-se, are not considered to be a threat. Our aim was therefore to evaluate the renal and hepatic safety, and measure plasma derivatives of a polyphenol-rich extract from grape and blueberry (PEGB; from the Neurophenols Consortium) in dogs. Polyphenol expression was analyzed by UHPLC-MS/MS over 8 hours, for dogs given PEGB at 4 mg/kg. Safety was evaluated using four groups of 6 dogs. These groups received capsules containing no PEGB (control), or PEGB at 4, 20, or 40 mg/kg BW/d, for 24 weeks. Blood and urine samples were taken the week prior to study commencement, then at the end of the 24-wk study period. Routine markers of renal and liver damage, including creatinine (Creat), blood urea nitrogen, albumin, minerals, alkaline phosphatase (ALP), and alanine transaminase (ALT) were measured. Biomarkers for early renal damage were also evaluated in plasma (cystatin C (CysC), and neutrophil gelatinase-associated lipocalin (NGAL)), and urine (CysC, clusterin (Clu), and NGAL). Ratios of urinary biomarkers to Creat were calculated, and compared with acceptable maximal values obtained for healthy dogs, as reported in the literature.

Results

While several PEGB-specific polyphenols and metabolites were detected in dog plasma, at the end of the PEGB consumption period, our biomarker analyses presented no evidence of either renal or liver damage (Creat, BUN, ionogram, albumin and ALT, ALP). Similarly, no indication of early renal damage could be detected. Plasma CysC, urinary CysC/Creat, Clu/Creat, and NGAL/Creat ratios were all beneath reported benchmarked maximums, with no evidence of PEGB toxicity.

Conclusions

Long-term consumption of a pet specific blend of a polyphenol-rich extract from grape and blueberry (PEGB; from the Neurophenols Consortium), was not associated with renal or hepatic injury, and can therefore be considered safe.

Other Risks/Possible Benefits of Obesity

Obesity is not a cosmetic or social issue; it is an animal health issue. The metabolic effects of obesity on insulin resistance and development of hyperlipidemia and the mechanical stress excess weight places on the musculoskeletal system are well established in the literature. Additional health risks from obesity, such as fatty accumulation in the liver, intestinal bacterial dysbiosis, and changes to renal architecture, are less well understood, but have been demonstrated to occur clinically in obese animals and may lead to deleterious long-term health effects. Keeping dogs and cats lean lowers their risk for development of certain diseases and leads to a longer and better quality of life.

Outcomes of weight management in obese pet dogs: what can we do better?

Obesity is arguably the biggest health and welfare issue affecting pet dogs. Although successful weight loss has health benefits, current strategies are far from ideal. Many obese dogs that start a weight programme fail to lose weight, or subsequently regain the weight they have lost. Given that current weight loss strategies are not perfect, clinicians need to focus carefully on tailoring the programme, perhaps setting a pragmatic target for weight loss, so as to ensure the benefits are maximised. This review will summarise key findings from recent clinical research into pet obesity, and present a framework for improving success, by better tailoring weight management regimens and end points to the individual.

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.

Cohort Study of the Success of Controlled Weight Loss Programs for Obese Dogs

BACKGROUND

Most weight loss studies in obese dogs assess rate and percentage of weight loss in the first 2-3 months, rather than the likelihood of successfully reaching target weight.

OBJECTIVE

To determine outcome of controlled weight loss programs for obese dogs, and to determine the factors associated with successful completion.

ANIMALS

143 obese dogs undergoing a controlled weight loss program.

METHODS

This was a cohort study of obese dogs attending a referral weight management clinic. Dogs were studied during their period of weight loss, and cases classified according to outcome as "completed" (reached target weight), "euthanized" (was euthanized before reaching target weight), or "stopped prematurely" (program stopped early for other reasons). Factors associated with successful completion were assessed using simple and multiple logistic regression.

RESULTS

87/143 dogs (61%) completed their weight loss program, 11 [8%] died or were euthanized, and the remaining 45 [32%] stopped prematurely. Reasons for dogs stopping prematurely included inability to contact owner, refusal to comply with weight management advice, or development of another illness. Successful weight loss was positively associated with a faster rate (P < .001), a longer duration (P < .001), and feeding a dried weight management diet (P = .010), but negatively associated with starting body fat (P < .001), and use of dirlotapide (P = .0046).

CONCLUSIONS AND CLINICAL RELEVANCE

Just over half of all obese dogs on a controlled weight loss program reach their target weight. Future studies should better clarify reasons for success in individual cases, and also the role of factors such as activity and behavioral modification.

2014 AAHA weight management guidelines for dogs and cats

Communicating and implementing a weight management program for dogs and cats can be a challenging endeavor for veterinarians, but a rewarding one. An effective individualized weight loss program provides a consistent and healthy rate of weight loss to reduce risk of disease, prevent malnutrition, and improve quality of life. Weight loss is achieved with appropriate caloric restriction, diet selection, exercise, and strategies to help modify behavior of both the pet and client. This document offers guidelines and tools for the management of weight loss and long-term maintenance of healthy weight.

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.

Style over substance: What can parenting styles tell us about ownership styles and obesity in companion animals?

Obesity is a major medical concern in human subjects, and most concerning is the rapid recent increase in childhood obesity. Children are more likely to be obese if their parents are obese, an effect that is mediated both by genetics and environment, most notably parental influence. Four major parenting styles have been recognised: authoritative; authoritarian; indulgent; uninvolved. Too much parental control, as with the authoritarian style, is associated with a higher weight status in children. Conversely, indulgent feeding styles can also have negative consequences and, where control is too lax, a poor relationship with food develops, which may also lead to weight gain. Obesity is also a growing concern in companion animals, and it has parallels with obesity in children. For instance, overweight people are more likely to own overweight dogs. Furthermore, the care that people provide for their pets mirrors that which parents provide for children, and pets are commonly viewed as child substitutes. These similarities raise obvious questions about whether different styles of pet ownership exist, and what part they may play in attitudes to feeding as well as predisposition to obesity in pets. Future work could focus on determining to what extent styles of pet ownership mirror parenting styles, whether there are links to obesity in dogs and cats. Knowledge regarding the owner-pet bond might provide comparative insights into the links between parenting styles and childhood obesity.

Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in cats with chronic kidney disease

Background

Symmetric dimethylarginine (SDMA) has been shown to be an accurate and precise biomarker for calculating estimated glomerular filtration rate (GFR) in humans, as well as a more sensitive biomarker than serum creatinine concentration (sCr) for assessing renal dysfunction.

Objectives

The purpose of this retrospective study was to report on the utility of measuring serum SDMA concentrations in cats for detection of chronic kidney disease (CKD) before diagnosis by conventional measurement of sCr.

Animals

Chronic kidney disease cats (n = 21) included those persistently azotemic for ≥3 months (n = 15), nonazotemic cats with GFR >30% decreased from median GFR of normal cats (n = 4), and nonazotemic cats with calcium oxalate kidney stones (n = 2). Healthy geriatric cats (n = 21) were selected from the same colony.

Methods

Symmetric dimethylarginine concentrations (liquid chromatography‐mass spectroscopy) and sCr (enzymatic colorimetry) were determined retrospectively from historical data or banked serum samples in azotemic cats or at the time GFR (iohexol clearance) was measured in nonazotemic cats.

Results

Serum SDMA (r = −0.79) and sCr (r = −0.77) concentrations were significantly correlated to GFR (both P < .0001). Symmetric dimethylarginine became increased before sCr in 17/21 cats (mean, 17.0 months; range, 1.5–48 months). Serum SDMA had higher sensitivity (100%) compared with sCr (17%), but lower specificity (91% versus 100%) and positive predictive value (86% versus 100%).

Conclusion and Clinical Importance

Using serum SDMA as a biomarker for CKD allows earlier detection of CKD in cats compared with sCr, which may be desirable for initiating renoprotective interventions that slow progression of CKD.

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.

Association between excess body weight and urine protein concentration in healthy dogs

BACKGROUND

Markedly overweight people can develop progressive proteinuria and kidney failure secondary to obesity-related glomerulopathy (ORG). Glomerular lesions in dogs with experimentally induced obesity are similar to those in people with ORG.

OBJECTIVES

The aim of this study was to evaluate if urine protein and albumin excretion is greater in overweight and obese dogs than in dogs of ideal body condition.

METHODS

Client-owned dogs were screened for underlying health conditions. These dogs were assigned a body condition score (BCS) using a 9-point scoring system. Dogs with a BCS of ≥ 6 were classified as being overweight/obese, and dogs with a BCS of 4 or 5 were classified as being of ideal body weight. The urine protein:creatinine ratio (UPC) and urine albumin:creatinine ratio (UAC) were then determined, and compared between 20 overweight/obese dogs and 22 ideal body weight control dogs.

RESULTS

Median UPC (0.04 [range, 0.01-0.14; interquartile range, 0.07]) and UAC (0.41 [0-10.39; 3.21]) of overweight/obese dogs were not significantly different from median UPC (0.04 [0.01-0.32; 0.07]) and UAC (0.18 [0-7.04; 1.75]) in ideal body weight dogs.

CONCLUSIONS

Clinicopathologic abnormalities consistent with ORG were absent from overweight/obese dogs in this study.

Status of selected nutrients in obese dogs undergoing caloric restriction

BACKGROUND

The purpose of this study was to test the hypothesis that dog plasma concentrations of selected nutrients decrease after undergoing caloric restriction for weight loss. Thirty-one overweight dogs that had successfully lost at least 15% of initial body weight were included in the study. Nutrients that had been previously identified to be at potential risk of deficiency during caloric restriction were measured in plasma (choline, amino acids) and urine (selenium) at the initiation and completion of a standardized weight loss regimen in dogs.

RESULTS

Dogs remained healthy throughout the study, and no signs attributable to nutrient deficiency were noted. Percentage weight loss was 28.3% (16.0-40.1%) starting body weight, over a period of 250 days (91-674 days). Median energy intake during the weight loss period was 62 (44 to 74) Kcal/kg(0.75) target weight per day. Choline (P = 0.046) and threonine (P = 0.02) decreased after weight loss. Glycine (P = 0.041), and urinary selenium:creatinine ratio (P = 0.006) both increased after weight loss. There were no other significant differences in plasma nutrient concentrations.

CONCLUSIONS

Since concentrations of most measured nutrients did not change significantly, the data are not consistent with widespread nutrient deficiency in dogs undergoing caloric restriction using a diet formulated for weight loss. However, the significance of the decrease in plasma choline concentration requires further assessment.

Obesity-related metabolic dysfunction in dogs: a comparison with human metabolic syndrome

BACKGROUND

Recently, metabolic syndrome (MS) has gained attention in human metabolic medicine given its associations with development of type 2 diabetes mellitus and cardiovascular disease. Canine obesity is associated with the development of insulin resistance, dyslipidaemia, and mild hypertension, but the authors are not aware of any existing studies examining the existence or prevalence of MS in obese dogs.Thirty-five obese dogs were assessed before and after weight loss (median percentage loss 29%, range 10-44%). The diagnostic criteria of the International Diabetes Federation were modified in order to define canine obesity-related metabolic dysfunction (ORMD), which included a measure of adiposity (using a 9-point body condition score [BCS]), systolic blood pressure, fasting plasma cholesterol, plasma triglyceride, and fasting plasma glucose. By way of comparison, total body fat mass was measured by dual-energy X-ray absorptiometry, whilst total adiponectin, fasting insulin, and high-sensitivity C-reactive protein (hsCRP) were measured using validated assays.

RESULTS

Systolic blood pressure (P = 0.008), cholesterol (P = 0.003), triglyceride (P = 0.018), and fasting insulin (P < 0.001) all decreased after weight loss, whilst plasma total adiponectin increased (P = 0.001). However, hsCRP did not change with weight loss. Prior to weight loss, 7 dogs were defined as having ORMD, and there was no difference in total fat mass between these dogs and those who did not meet the criteria for ORMD. However, plasma adiponectin concentration was less (P = 0.031), and plasma insulin concentration was greater (P = 0.030) in ORMD dogs.

CONCLUSIONS

In this study, approximately 20% of obese dogs suffer from ORMD, and this is characterized by hypoadiponectinaemia and hyperinsulinaemia. These studies can form the basis of further investigations to determine path genetic mechanisms and the health significance for dogs, in terms of disease associations and outcomes of weight loss.