The Bone Marrow Protects and Optimizes Immunological Memory during Dietary Restriction.

Mammals evolved in the face of fluctuating food availability. How the immune system adapts to transient nutritional stress remains poorly understood. Here, we show that memory T cells collapsed in secondary lymphoid organs in the context of dietary restriction (DR) but dramatically accumulated within the bone marrow (BM), where they adopted a state associated with energy conservation. This response was coordinated by glucocorticoids and associated with a profound remodeling of the BM compartment, which included an increase in T cell homing factors, erythropoiesis, and adipogenesis. Adipocytes, as well as CXCR4-CXCL12 and S1P-S1P1R interactions, contributed to enhanced T cell accumulation in BM during DR. Memory T cell homing to BM during DR was associated with enhanced protection against infections and tumors. Together, this work uncovers a fundamental host strategy to sustain and optimize immunological memory during nutritional challenges that involved a temporal and spatial reorganization of the memory pool within "safe haven" compartments.

Intake of energy, protein, amino acids and minerals by dogs under energy restriction for body weight loss when fed with commercial weight loss diets.

This retrospective study evaluated energy and nutrient intake of dogs in a weight loss programme. Ninety-four obese dogs were divided into three groups: G5-15: from 5% to 15% body weight (BW) loss (n = 55); G155-25: from 15.1% to 25% BW loss (n = 29); and G > 25: more than 25.1% BW loss (n = 10). Five brands of kibble diets designed for weight loss were analysed for crude protein, amino acids, fat, dietary fibre, and minerals. The food metabolizable energy (ME) was estimated (NRC, 2006). Data were compared inside each group using the paired t test and between groups with analysis of variance and Tukey tests (p < 0.05). The BW loss (weeks in regimen) was: G5-15, 9.8% ± 2.7% (13.5 ± 5.7 weeks); G15-25, 17.5% ± 2.7% (22.6 ± 11.9 weeks); G > 25, 30.0% ± 2.1% (50.4 ± 17.4% weeks; p < 0.01). The mean weekly BW loss rate was similar between groups (0.8% ± 0.3%; p > 0.05) but was higher during the first (0.96.6% ± 0.5%) than in the second (0.64% ± 0.4%) half of the regimen (p < 0.01). At beginning ME intake for BW loss did not differ (251.6 ± 32.2 kJ/kg0.75 /day), but it was lower for G > 25 in the second half of the regimen (230.3 ± 44.3; p = 0.02). Considering the observed ME intake of each dog, depending on the commercial product, intake below recommended for maintenance was verified for crude protein in 1%-20% of the dogs, methionine in 4%-38% of dogs, methionine plus cystine in 4%-22% of dogs, tryptophan in 7%-93% of dogs, potassium in 2%-85% of dogs and magnesium in 1% up to 95% of dogs. Although the diets presented elevated nutrient concentrations per MJ, due to the reduced energy allowance, the estimated intake of several nutrients was lower than the recommendations, highlighting the importance of changing the formulation perspective, which must prioritize the actual nutrient intake per kg of BW during the energy deficit.

Nutritional Considerations When Dealing with an Obese Adult Equine.

Equine obesity is common, reducing quality of life and requiring dietary energy restriction. Equine obesity is identified using subjective body condition scoring. Considerations are given for life stage and health status when managing obese equines. Every effort should be made to maximize feeding duration, and minimize time spent without feed while meeting all essential nutrient requirements. Limiting total daily dry matter intake to 2% of current bodyweight per day of a low caloric, forage-based diet may result in adequate body weight loss. Weight loss and weight management plans should be monitored for success and potential gastrointestinal, metabolic, and/or behavioral complications.

Dietary intake of amino acids and vitamins compared to NRC requirements in obese cats undergoing energy restriction for weight loss.

BACKGROUND: This study aimed to determine if obese cats undergoing energy restriction for weight loss would meet the National Research Council's (NRC) indispensable amino acid and vitamin recommendations when fed a purpose-formulated diet. Thirty cats were placed into one of two groups; obese (BCS 8 to 9/9; n = 16) and lean (BCS 4 to 5/9; n = 14) and included in a non-randomized retrospective observational study. Cats were fed a veterinary weight loss food during a 4-week period of weight maintenance. Obese cats (O-MAINT) refers to obese cats during this period, L-MAINT to lean cats. After this initial 4-week period, the lean cats finished the study at this time and the 16 obese cats continued and were energy restricted for a 10-week period (O-RESTRICT). Analysis for dietary concentrations of indispensable amino acid and vitamin contents were performed. Daily food intakes were used to determine minimum, maximum and average daily intakes of individual nutrients for all three groups and compared against NRC 2006 minimum requirements (MR), adequate intakes (AI) and recommended allowances (RA) for adult cats. RESULTS: Over 10 weeks, O-RESTRICT cats lost 672 g ± 303 g, representing a weight loss rate of 0.94 ± 0.28% per week. Daily intake of the majority of indispensable amino acids and vitamins was greater than the NRC 2006 recommended allowance (RA per kg ideal body weight ^0.67), except for arginine, choline, crude protein, phenylalanine plus tyrosine and threonine. All O-RESTRICT cats had minimum, average, and maximum arginine intakes less than the NRC AI. Minimum daily intake of choline was below NRC RA for all O-RESTRICT cats and below NRC MR for two. All, except one, O-RESTRICT cats had a maximum and average choline intake below RA. CONCLUSIONS: All cats remained clinically healthy and showed no clinical signs of deficiency. Dietary choline and arginine requirements of obese cats as well as health risks associated with low dietary intake during energy restriction warrant further investigation.

Factors associated with overweight cats successfully completing a diet-based weight loss programme: an observational study.

BACKGROUND: The most common approach for controlled weight loss in cats is dietary caloric restriction, using a purpose-formulated diet. Most previous studies have only assessed short-term outcomes, and no previous study has examined overall success (i.e. odds of reaching target weight). The aim of this study was to determine the factors associated with overweight cats successfully completing a diet-based weight loss programme to reach target weight. RESULTS: Sixty-two cats were included, and 28 (45%) completed their weight loss programme. The remaining 34 cats (55%) did not reach target weight, of which 2 (3%) were euthanised for unrelated reasons. Reasons for cats stopping the programme prematurely included inability to contact owner (n = 19), owner requested that the programme be completed prior to reaching target weight (n = 5), the cat developed another illness (n = 3), refusal to comply with requirements for weight management (n = 2), owner illness (n = 2), and personal issues of the owner (n = 1). Multiple logistic regression analysis revealed that rate of weight loss and weight loss required were positively (odds ratio [OR] 157.81, 95% confidence interval [CI] 10.00-2492.67) and negatively (OR 0.89, 95% CI 0.81-0.98) associated with the odds of completing the weight loss programme, respectively. CONCLUSIONS: Future studies should consider developing better methods of supporting the owners of the most obese cats during weight management, since these cats are least likely to complete reach target weight.

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.

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.

Evaluation of the use of esterified fatty acid oils enriched in medium-chain fatty acids in weight loss diets for dogs.

Esterified fatty acid oils (EAOs) are obtained from esterification of vegetable acid oils with glycerol. These fat sources have the same fatty acid (FA) composition as their respective native oils but new chemical properties. Several studies have confirmed the potential of medium-chain fatty acids (MCFA) to reduce fat mass (FM) in humans and rodents. This study investigates the use of EAOs with different MCFA proportions on food preferences, digestibility and weight loss management in dogs. A basal diet was supplemented with 8% of three different fat sources: C0: soya bean-canola EAO, C20: soya bean-canola (80%) coconut (20%) EAO and C40: soya bean-canola (60%) coconut (40%) EAO. Food preference of these EAOs was tested using a two-pan preference test. Dogs presented a higher daily food intake of C20 and C40 compared to C0 (C20: 155 ± 18.6 g vs. C0: 17 ± 7.0 g, p < 0.001; C40: 117 ± 13.9 g vs. C0: 28 ± 10.5 g, p < 0.05 respectively). Also, the digestibility of the three experimental diets was tested. C20 and C40 showed higher ether extract, total FA and saturated FA digestibilities (p < 0.05) than C0 diet. Lastly, the three diets were investigated in a 14-week weight loss study, following 16 weeks of ad libitum feeding to induce overweight condition. Body weight (BW) reduction was lower (C0: 20.1 ± 2.32%, C20: 14.6 ± 1.43% and C40: 15.7 ± 1.23%, p < 0.05) and FM was higher (FM, 18.7 ± 3.42%, 27.9 ± 3.90% and 28.2 ± 2.88% for C0, C20 and C40, respectively, p < 0.05) for diets C20 and C40 than for C0. Feeding diets with MCFA at these inclusion levels to experimentally overweight dogs during 14 weeks do not result in faster weight loss compared to unsaturated long-chain FA.

Changes in oxidative stress in response to different levels of energy restriction in obese ponies.

The present study evaluated the effect of different levels of energy restriction on metabolic parameters in obese ponies. Relative weight changes, markers of lipid metabolism and oxidant/antioxidant balance were monitored. A total of eighteen obese (body condition score ≥ 7/9) Shetland ponies were studied over a 23·5-week trial, which was divided into three periods. The first period involved a 4-week adaptation period in which each animal was fed 100% of their maintenance energy requirements needed to maintain a stable obese body weight (MERob). This was followed by a 16·5-week weight-loss period in which ponies were assigned to receive either 100% (control group, CONTROL), 80% (slow weight-loss (SLOW) group) or 60% (rapid weight-loss (RAPID) group) of their MERob. During the 3-week end-phase period, all ponies were again fed 100% of their MERob. Relative weight loss was higher in the RAPID group (P< 0·001) compared with the SLOW group. No linear relationship was found as a doubling of the percentage of energy restriction was accompanied by a tripling of the percentage of weight loss. Relative weight gain afterwards in the end-phase period was higher in the RAPID group (P< 0·001) compared with the SLOW and CONTROL groups. During the weight-loss period, TAG and NEFA concentrations were highest in the RAPID group, as were α-tocopherol and ferric-reducing ability of plasma concentrations. After 8 weeks of weight loss, the concentrations of advanced oxidation protein products were higher in the RAPID group compared with the SLOW and CONTROL groups (P< 0·001). In conclusion, the level of energy restriction influences the extent of changes in oxidant/antioxidant balance. Practically, more severe energy restriction regimens may be associated with a greater regain of weight after the restriction period.

Effects of a therapeutic weight loss diet on weight loss and metabolic health in overweight and obese dogs.

Obesity has become a major health issue in dogs. Obesity in dogs increases the risk of many chronic diseases and chronic low-grade inflammation. The objective of this study was to determine the effect of a therapeutic weight loss (TWL) diet on weight loss and metabolic health in overweight and obese dogs. Thirty overweight and obese dogs were randomized into two groups with 15 dogs per group based on key baseline (BSL) parameters and allotted to either a control or TWL diet for 6 mo. At the start of the study, the control group had six females and nine males with mean age of 9.12 ±â€…0.48 (mean ±â€…SEM) yr; there were seven females and eight males with mean age of 9.73 ±â€…0.63 yr in the TWL group. The control group and the TWL group had comparable body weight (34.78 ±â€…0.76 and 34.63 ±â€…0.86 kg, respectively), % body fat (BF; 39.77 ±â€…1.18 and 39.89 ±â€…0.93, respectively), and body condition score (BCS; 7.80 ±â€…0.14 and 7.67 ±â€…0.16 on a 9-point BCS scale, respectively). The control (CTRL) diet was formulated based on the macronutrient ratio of a commercial metabolic diet, and the TWL diet was enriched with dietary protein, fish oil, and soy germ meal. Both diets were fortified with essential nutrients to account for caloric restriction during weight loss. Dogs were fed with 25% less than BSL maintenance energy requirement (MER) for the first 4 mo and if they did not reach a BCS of 5, they were fed 40% less than BSL MER for the last 2 mo. Body composition was determined by dual-energy x-ray absorptiometry. Postprandial glucose profiles were determined by continuous glucose monitoring devices. Serum samples were collected for analyses of blood parameters, hormones, and cytokines. All data were analyzed using SAS 9.3, with significance being P < 0.05. At the end of the study, the control group and the TWL group had comparable weight loss (-5.77 ±â€…0.31 and -6.14 ±â€…0.32 kg, respectively; P = 0.4080). But the TWL group lost significantly (P = 0.034) more BF (-13.27 ±â€…1.28%) than the control group (-9.90 ±â€…1.23%). In addition, the TWL diet completely prevented loss of lean body mass (LBM) in dogs compared with BSL. Dogs fed with the TWL diet had significantly lower fasting serum cholesterol, triglycerides, insulin, leptin, mean postprandial interstitial glucose, and pro-inflammatory cytokines compared with dogs fed with the CTRL diet. In summary, the TWL diet prevented loss of LBM, promoted weight loss and metabolic health, and reduced pro-inflammatory cytokines and chemokines in overweight and obese dogs during weight loss.

Obesity has become a major health issue in dogs and increases the risk of many chronic diseases and chronic low-grade inflammation. The objective of this study was to determine the effect of a therapeutic weight loss (TWL) diet on weight loss and metabolic health in overweight and obese dogs. Thirty overweight and obese dogs were randomized into two groups with 15 dogs per group and assigned to either a control (CTRL) diet or TWL diet for a 6 mo weight loss study. Changes in body composition were determined every 2 mo. Blood samples were collected to measure changes in lipid profiles, hormones, cytokines, and chemokines. Postprandial glucose profiles were determined by a continuous glucose monitoring system. The results of the study showed that the TWL diet completely prevented loss of lean body mass (LBM) in dogs compared with baseline. Dogs fed with the TWL diet had significantly lower fasting serum cholesterol, triglycerides, insulin, leptin, mean postprandial glucose, and pro-inflammatory cytokines compared with dogs fed with the CTRL diet. In summary, the TWL diet prevented loss of LBM, promoted weight loss and metabolic health, and reduced pro-inflammatory cytokines in overweight and obese dogs during weight loss.

Clinical Guide to Obesity and Nonherbal Nutraceuticals in Canine Orthopedic Conditions.

The typical canine rehabilitation patient with orthopedic disease may differ in its nutritional needs, with the assumption that most patients will be on a complete and balanced commercial dog food that is not enriched with agents for ameliorating their condition. For a significant number of rehabilitation patients, obesity is a major issue where hypocaloric diet plans are often implemented and are covered extensively elsewhere (VCNA Small Animal Practice May 2021). The focus of this article will be implementation of physical activity or structured physical exercise protocols and how they might be used in combination with a typical hypocaloric diet plan, a diet low in calories. Considering the limited information regarding physical activity or structured exercise programs in dogs, a human comparative assessment of efficacy is fundamental as a baseline of information regarding typical interventions. In addition, many of these long-term rehabilitation cases typically exhibit osteoarthritis (OA) and as part of case management, there is a need to implement nutrient or nutraceutical intervention to either diminish the progression of OA or help with pain control measures, particularly for the nonsteroidal anti-inflammatory intolerant patient. Nutraceutical intervention comes in many forms from botanicals to nutritional enhancement; botanicals will be covered elsewhere in this issue. This overview of nutraceuticals will cover nonbotanical interventions including fish oil, glucosamine/chondroitin, avocado/soybean unsaponifiables, undenatured collagen, green lipped mussel, and egg shell membrane supplementation.

Equine metabolic syndrome.

The concept of an equine metabolic syndrome (EMS) was first proposed in 2002. This concept has developed over time, and EMS was recently described in a consensus statement released by the American College of Veterinary Internal Medicine. In human medicine, metabolic syndrome (MetS) refers to a set of risk factors that predict the risk of cardiovascular disease, including obesity, glucose intolerance and insulin resistance (IR), dyslipidemia, microalbuminuria, and hypertension. EMS shares some of the features of MetS, including increased adiposity, hyperinsulinemia, IR, but differs in that laminitis is the primary disease of interest.

Effect of food toys on owner-perceived quality of life of cats during a prescribed weight loss plan.

OBJECTIVE: To determine the effect of a food toy on owner-perceived quality of life (QOL) of overweight cats during a weight loss plan. ANIMALS: 44 adult cats, 1 to 10 years of age with a body condition score (BCS) ≥ 7/9. PROCEDURES: Cats were randomly assigned to the food toy or food bowl group. Cat owners completed an initial questionnaire and received a prescribed weight loss plan, bag of dry veterinary therapeutic cat food formulated for weight loss, measuring cup, and food bowl or ball-type food toy. Body weight and BCS were checked monthly. Owners completed a monthly questionnaire to assess their cat's QOL. Low-calorie vegetables were offered to 32 cats whose owners reported disruptive food-seeking behavior. RESULTS: Of the 44 cats in the final analysis, 29 cats either lost ≥ 2 BCS points or achieved an ideal BCS. Owner-perceived QOL was higher at the final weigh-in, compared with that at the initial weigh-in. An effect of food toy versus food bowl on owner-perceived QOL was not detected. Of the cats offered vegetables, 28 cats would eat the vegetables with a palatability additive; 4 cats ate vegetables plain. CONCLUSIONS AND CLINICAL RELEVANCE: Owner-perceived QOL was higher at the end of the study. Feeding overweight cats by use of a ball-type food toy did not influence owner-perceived QOL. Low-calorie vegetables can successfully be added to the weight loss diet to promote satiety; albeit, a palatability additive is likely needed. Further studies regarding feeding management for cats during a weight loss plan should be explored.

Canine and Feline Obesity Management.

Obesity and overweight have an impact on more than half of pet cats and dogs. Effective and team-based communication is essential for creating an effective weight loss plan. The diet should meet all essential nutrient requirements during energy/calorie restriction. There are several ways to initiate a weight loss plan, and regular monitoring is essential for determining if a plan is working or needs to be adjusted.

Evaluation of calorie density and feeding directions for commercially available diets designed for weight loss in dogs and cats.

OBJECTIVE: To determine range of calorie density and feeding directions for commercially available diets designed for weight management in dogs and cats. DESIGN: Cross-sectional study. SAMPLE POPULATION: 93 diets (44 canine diets and 49 feline diets) that had a weight management claim with feeding directions for weight loss or implied weight management claims. PROCEDURES: Calorie density was collected from product labels or by contacting manufacturers. Recommended feeding directions for weight loss were compared with resting energy requirement (RER) for current body weight by use of a standard body weight (36.4 kg [80 lb] for canine diets and 5.5 kg [12 lb] for feline diets). RESULTS: Calorie density for the 44 canine diets ranged from 217 to 440 kcal/cup (median, 301 kcal/cup) and from 189 to 398 kcal/can (median, 310 kcal/can) for dry and canned diets, respectively. Calorie density for the 49 feline diets ranged from 235 to 480 kcal/cup (median, 342 kcal/cup) and from 78 to 172 kcal/can (median, 146 kcal/can) for dry and canned diets, respectively. Recommended calorie intake for weight loss in dogs ranged from 0.73 to 1.47 x RER (median, 1.00 x RER) and for weight loss in cats ranged from 0.67 to 1.55 x RER (median, 1.00 x RER). Diets ranged from $0.04 to $1.11/100 kcal of diet (median, $0.15/100 kcal of diet). CONCLUSIONS AND CLINICAL RELEVANCE: Wide variation existed in recommended calorie intake, kilocalories, and cost for diets marketed for weight loss in pets. This variability could contribute to challenges of achieving successful weight loss in pets.

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.

Moderate daily exercise activates metabolic flexibility to prevent prenatally induced obesity.

Obesity and its associated comorbidities are of major worldwide concern. It is now recognized that there are a number of metabolically distinct pathways of obesity development. The present paper investigates the effect of moderate daily exercise on the underlying mechanisms of one such pathway to obesity, through interrogation of metabolic flexibility. Pregnant Wistar rats were either fed chow ad libitum or undernourished throughout pregnancy, generating control or intrauterine growth restricted (IUGR) offspring, respectively. At 250 d of age, dual-emission x-ray absorptiometry scans and plasma analyses showed that moderate daily exercise, in the form of a measured amount of wheel running (56 m/d), prevented the development of obesity consistently observed in nonexercised IUGR offspring. Increased plasma C-peptide and hepatic atypical protein kinase Czeta levels explained increased glucose uptake and increased hepatic glycogen storage in IUGR offspring. Importantly, whereas circulating levels of retinol binding protein 4 were elevated in obese, nonexercised IUGR offspring, indicative of glucose sparing without exercise, retinol binding protein 4 levels were normalized in the exercised IUGR group. These data suggest that IUGR offspring have increased flexibility of energy storage and use and that moderate daily exercise prevents obesity development through activation of distinct pathways of energy use. Thus, despite a predisposition to develop obesity under sedentary conditions, obesity development was prevented in IUGR offspring when exercise was available. These results emphasize the importance of tailored lifestyle changes that activate distinct pathways of metabolic flexibility for obesity prevention.

A longitudinal study of the influence of lifetime food restriction on development of osteoarthritis in the canine elbow.

OBJECTIVE: To report the effects of age and lifetime calorie restriction on development and progression of osteoarthritis (OA) in elbow joints of Labrador retrievers. STUDY DESIGN: Longitudinal cohort study. ANIMALS: Labrador retriever dogs (n=48). METHODS: Puppies from 7 litters were allotted to 2 groups of 24 dogs each. Diet-restricted (DR) dogs received 25% fewer calories than control-fed (CF) pair mates. Elbow radiographs were taken at 6 and 8 years of age and end of life (EOL). Gross and histopathologic evaluations for OA occurred at EOL. RESULTS: There was no statistical difference in radiographic OA frequency between groups at any of the time points. Radiographic OA severity was greater for CF dogs at 6 years only (P<.05). There was no significant difference between feeding groups for histopathologic prevalence or severity of OA. Similarly, there were no differences in gross OA lesions between the groups (P>.05). Fragmented medial coronoid process, un-united anconeal process, and osteochondrosis were not present in any elbow. CONCLUSION: No differences in prevalence or severity of radiographic and histopathologic elbow OA were found between feeding groups. Diet restriction resulted in a 1.8-year extension in median lifespan but no additional incremental worsening of elbow disease. Evaluation at time points <6 years may have revealed larger differences in OA prevalence and severity between the dietary groups. CLINICAL RELEVANCE: These findings support calorie restriction as a clinical tool to slow progression of elbow OA.

Un-united medial epicondyle of the humerus: radiographic prevalence and association with elbow osteoarthritis in a cohort of labrador retrievers.

OBJECTIVE: To longitudinally characterize the radiographic appearance of un-united medial epicondyle (UME) of the humerus, evaluate UME association with osteoarthritis (OA) and consider its relevance to the elbow dysplasia complex. STUDY DESIGN: Longitudinal cohort study. ANIMALS: Labrador retrievers (n=48) from 7 litters. METHODS: Forty-eight same-sex littermates were paired for this lifetime feeding study. One of each pair was control-fed; the pair mate was fed 25% less than the control each day. Elbows of 46 surviving dogs were radiographed at ages 6 and 8 years, and/or at end-of-life (EOL). Elbow histopathology was done EOL, although UME lesions were not evaluated histologically. RESULTS: Seven dogs (15%) had UME, representing 5 litters; 4 were control-fed, 3 diet-restricted. Six (86%) dogs had unilateral lesions; 1 was bilateral. UME was evident on craniocaudal (CrCd) radiographic projections by 8 years in all dogs. UME was detected in only 1 elbow by mediolateral radiographic projection. Elbow OA frequency in UME affected dogs was not significantly different from the remaining study population. Histopathologic lesions were bilateral in dogs with unilateral UME. CONCLUSIONS: UME may be more common than previously thought. Most cases were unilateral and diet restriction had no effect on frequency. The CrCd view was critical for diagnosis. Elbow OA was not directly associated with UME. CLINICAL RELEVANCE: Infrequent diagnosis of UME could result from infrequent radiography and use of only the flexed lateral radiographic projection required by the Orthopedic Foundation for Animals for elbow screening. Like hip evaluations, screening for UME should be continued for life, until genetics are better understood. Lack of association between UME and elbow OA suggests that UME is not likely a component of elbow dysplasia.

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.