Nicholas J. Cave

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

A high concentration of dietary carbohydrate is suggested to increase the risk of obesity and diabetes mellitus in domestic cats. To evaluate this, food intake, body weight, fat mass and circulating adiposity-related factors were determined in twenty-four sexually mature (9-12 months) cats assigned to four six-cat dietary groups balanced for body weight and sex. The effect of dietary fat in exchange for carbohydrate at 9, 25, 44 and 64 % of metabolisable energy (ME) in a purified diet of constant protein:ME ratio was studied 13 weeks before and 17 weeks after gonadectomy (GX). Body weight did not significantly change among the cats before GX except for an increase of 17 (sem 5) % in cats given the highest-fat diet. Following GX, all groups gained body weight, and body fat mass was positively correlated (r 0.50; P < 0.04) with dietary fat percentage. Post-GX weight gains were much greater for females (+39 (sem 5) %) than males (+10 (sem 4) %). Plasma ghrelin concentration negatively correlated (P < 0.02) with dietary fat percentage and, before GX, was greater (P < 0.05) in females than males. Plasma insulin concentration increased with weight gain induced by high dietary fat. Plasma glucose, TAG and leptin concentrations were not affected by dietary fat percentage, GX or weight gain. These data provide evidence that in cats, high dietary fat, but not carbohydrate, induces weight gain and a congruent increase in insulin, while GX increases sensitivity to weight gain induced by dietary fat.

WSAVA Nutritional Assessment Guidelines

Objectives Careful assessment of the nutritional needs of cats and dogs must be taken into consideration in order to maintain optimum health, be part of a treatment regimen for a diseased state, or to maximize the quality of life in all animals. The goal of these World Small Animal Veterinary Association (WSAVA) Guidelines is that a nutritional assessment and specific nutritional recommendation is made for every patient on every visit. This will become known as the 5th Vital Assessment (5VA), following the four vital assessments of temperature, pulse, respiration and pain that are already addressed on each patient interaction. Evaluation of nutritional status A brief screening evaluation of nutritional status can be routinely and seamlessly performed during the history-taking and physical examination of every patient. Nutrition-related risk factors that can be easily identified from the history and physical examination include age (growing or old), suboptimal body condition score (overweight or thin), muscle loss, atypical or homemade diet, medical conditions or changes in appetite. An extended evaluation would follow if one or more risk factors is identified on screening. These guidelines provide criteria with which to evaluate the animal and the diet, as well as key feeding and environmental factors. In addition, recommendations for interpretation, analysis and action are included so that a plan for optimizing the animals nutritional status can be instituted. Team approach Client compliance with nutritional recommendations requires input from the veterinarian, veterinary technicians/nurses and hospital staff. A team approach to continuous nutritional education, implementation of appropriate protocols, and focused client communication, utilizing these WSAVA Nutritional Assessment Guidelines, is key to reaching this 5VA goal.

Oestradiol and genistein reduce food intake in male and female overweight cats after gonadectomy

Abstract AIM: To determine if exogenous oestradiol or the phyto-oestrogen genistein could reduce food intake in male and female cats fed ad libitum that had been allowed to accrue excessive bodyfat following neutering. METHODS: Sixteen adult (eight female, eight male) cats were neutered and allowed to increase their bodyweight (BW) through feeding ad libitum of a complete and balanced dry diet. Oestradiol was injected subcutaneously for 5-day periods in incremental doses (0.25–4 µg per cat), then food intake was recorded, and vaginal cytological changes were observed in females. Similarly, genistein was administered orally for 5-day periods in incremental doses (5–100 mg/kg). RESULTS: In males and females, both oestradiol (p<0.001) and genistein (p=0.037) significantly reduced food intake during treatment, and the minimum daily doses that produced a significant effect were 0.5 µg and 100 mg/kg, respectively. The minimum daily dose of oestradiol that produced a significant effect on food intake was not associated with changes in vaginal cytology over the 5-day treatment period. CONCLUSIONS AND CLINICAL RELEVANCE: Gonadal oestradiol appeared to be a key modulator of food intake in both male and female cats, and replacement of oestrogen to neutered cats via oestradiol or an oestrogen surrogate such as genistein has potential for reducing the prevalence of obesity in neutered cats.

Chronic inflammatory disorders of the gastrointestinal tract of companion animals.

Abstract In the inflammatory bowel diseases (IBD) that affect dogs and cats there appears to be dysregulation of normal mucosal immunity, characterised by polyclonal lymphocytic infiltrates which are presumably specific for luminal antigens. There is an absence of a classical polarisation of either T-helper (Th) 1 or Th2 cytokine responses, although increased expression of mRNA for interleukin (IL) 2 and IL-12p40 and a shift towards mucosal immunoglobulin (Ig) G production are consistent findings, whilst variable responses are seen in tumour necrosis factor-α (TNF-α), IL-1, IL-4, IL-6, and interferon-γ (IFN-γ). Increased mucosal permeability and deranged intestinal motility are common sequelae. Despite obvious similarities with Crohn’s disease and ulcera- tive colitis in humans, important differences exist. Of these, the diffuse superficial nature but with no Th1 or Th2 bias, and the prevalence of proximal small intestinal disease are notable. Potential hypotheses for these disparities include specific differences in the types or locations of “agonistic” gut flora, diffuse abnormalities in microbial-host interactions, a greater importance of diet, or anatomical or cellular differences in mucosal immune responses. Although specific pathogens and genetic susceptibilities may be involved, quantitative or qualitative changes in the normal flora or abnormal responses to a normal flora are more likely to be involved in the immunopathogenesis. Dietary influences include a large source of antigen, promotion of abnormal microbial growth through Maillard compounds within canned diets, and specific macro- and micronutrient deficiencies. Although dependent on a histopathological diagnosis, limitations of biopsies procured endoscopically, lack of histopathological standardisation and difficulty distinguishing inflammation from neoplasia remain significant problems. Clinician-pathologist dialogue, immunohistochemistry, cytokine profiling and lymphocyte-clonality assessment may lead to more accurate diagnoses, a deeper understanding of the immunopathogenesis, and ultimately to new therapies or prevention of disease induction.

A survey of diseases of working farm dogs in New Zealand.

Abstract AIMS: To record the incidence of specific diseases affecting working farm dogs; identify any apparent breed predispositions; determine the most important causes of loss from death, euthanasia, or retirement of the dog; and identify potential interventions that could reduce the incidence of disease. METHODS: A national questionnaire-based cross-sectional study was conducted to identify the incidence of specific diseases, and circumstances of trauma affecting working farm dogs that presented to rural veterinary practices over a 12-month period, between April 2008 and April 2009. The practices were convenience-sampled on the basis of geography and size. RESULTS: Sixty-six practices were approached, and veterinarians from 30 practices agreed to participate, with representation from all major rural regions of New Zealand. Data were provided on 2,214 presentations, excluding revisits, of which 51% were for Huntaways and 39% Heading dogs. Trauma was identified as a cause of injury in 848 (38%) visits. Huntaways were apparently over-represented in cases of constipation, gastric dilatation-volvulus (GDV), theriogenological problems, laryngitis, hip dysplasia, and degenerative lumbosacral disease. In contrast, Heading dogs were over-represented among cases of multiple ligamentous injury of the stifle, disruption of the gastrocnemius or Achilles tendon, tarsal injuries, and hip luxation. Traumatic injury involved injury by stock (20%), automotive incidents (19%), transit across fence lines (16%), and dog bites (12%). Loss occurred following 10% of visits, of which trauma was known to be involved in 32%. The most important nontraumatic causes of loss were GDV, degenerative joint disease, mammary neoplasia and diseases involving the female reproductive tract, cardiac disease, and poisoning. CLINICAL RELEVANCE: Several important diseases appear amenable to intervention through nutrition, neutering, or behavioural modification, including constipation, GDV, theriogenological problems, dog-bite injuries, and laryngitis. Altering modes of transit across fence lines has the potential to reduce large numbers of serious orthopaedic injuries to working farm dogs.

Energy Requirements of Adult Dogs: A Meta-Analysis

A meta-analysis was conducted to determine the maintenance energy requirements of adult dogs. Suitable publications were first identified, and then used to generate relationships amongst energy requirements, husbandry, activity level, methodology, sex, neuter status, dog size, and age in healthy adult dogs. Allometric equations for maintenance energy requirements were determined using log-log linear regression. So that the resulting equations could readily be compared with equations reported by the National Research Council, maintenance energy requirements in the current study were determined in kcal/kg0.75 body weight (BW). Ultimately, the data of 70 treatment groups from 29 publications were used, and mean (± standard deviation) maintenance energy requirements were 142.8±55.3 kcal.kgBW−0.75.day−1. The corresponding allometric equation was 81.5 kcal.kgBW−0.93.day−1 (adjusted R2 = 0.64; 70 treatment groups). Type of husbandry had a significant effect on maintenance energy requirements (P<0.001): requirements were greatest in racing dogs, followed by working dogs and hunting dogs, whilst the energy requirements of pet dogs and kennel dogs were least. Maintenance energy requirements were less in neutered compared with sexually intact dogs (P<0.001), but there was no effect of sex. Further, reported activity level tended to effect the maintenance energy requirement of the dog (P = 0.09). This review suggests that estimating maintenance energy requirements based on BW alone may not be accurate, but that predictions that factor in husbandry, neuter status and, possibly, activity level might be superior. Additionally, more information on the nutrient requirements of older dogs, and those at the extremes of body size (i.e. giant and toy breeds) is needed.

Key bacterial families (Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae) are related to the digestion of protein and energy in dogs

Background Much of the recent research in companion animal nutrition has focussed on understanding the role of diet on faecal microbiota composition. To date, diet-induced changes in faecal microbiota observed in humans and rodents have been extrapolated to pets in spite of their very different dietary and metabolic requirements. This lack of direct evidence means that the mechanisms by which microbiota influences health in dogs are poorly understood. We hypothesised that changes in faecal microbiota correlate with physiological parameters including apparent macronutrient digestibility. Methods Fifteen adult dogs were assigned to two diet groups, exclusively fed either a premium kibbled diet (kibble; K; n = 8) or a raw red meat diet (meat; M; n = 7) for nine weeks. Apparent digestibility of macronutrients (protein, fat, gross energy and dry matter), faecal weight, faecal health scores, faecal VFA concentrations and faecal microbial composition were determined. Datasets were integrated using mixOmics in R. Results Faecal weight and VFA levels were lower and the apparent digestibility of protein and energy were higher in dogs on the meat diet. Diet significantly affected 27 microbial families and 53 genera in the faeces. In particular, the abundances of Bacteriodes, Prevotella, Peptostreptococcus and Faecalibacterium were lower in dogs fed the meat diet, whereas Fusobacterium, Lactobacillus and Clostridium were all more abundant. Discussion Our results show clear associations of specific microbial taxa with diet composition. For example, Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae were highly correlated to parameters such as protein and fat digestibility in the dog. By understanding the relationship between faecal microbiota and physiological parameters we will gain better insights into the effects of diet on the nutrition of our pets.

Design and evaluation of a novel chitosan-based system for colon-specific drug delivery

Tritrichomonas foetus is a flagellated protozoan parasite that colonizes the feline colon causing colitis and chronic foul smelling diarrhoea. Despite the efficacy of Ronidazole in the treatment of T. foetus, Ronidazole has been reported to cause neurotoxicity in some cats due to rapid absorption in the small intestine. A novel amphoteric derivative of chitosan was synthesised and characterized. A combination of time, pH, and an enzyme controlled system was used in a study of a new compression coated tablet for delivery of Ronidazole to the colon. Axial, radial swelling and erosion of selected tablets were carried out in various media. The effect of weight ratio, enzyme and pH on in vitro drug release profile was investigated. The results show that less than 2% of the drug was released in the physiological environment of the stomach and small intestine.

Systemic effects of periodontal disease in cats

Background: Periodontal disease in cats is a local disease that may have systemic consequences that are affected by treatment. Objective: To test the hypotheses that systemic health indices would be correlated with the severity of periodontitis, and would improve with treatment. Animals and methods: Apparently otherwise healthy cats from an in-bred colony were randomly assigned to a treatment group (n = 30), or a control group (n = 18), which was left untreated for 3 months. Periodontal disease was scored at baseline in the treatment group according to calculus, gingivitis, and alveolar bone loss measured from dental radiographs. Blood, urine and saliva were collected from both groups before, and 16, 45, and 90 days after dental treatment. Assays included haematology, urinalysis, serum biochemistry, serum IgG, salivary IgA, lymphocyte subsets and proliferation, and plasma malonyldialdehyde (MDA). Correlations between the severity of periodontitis and assays at baseline were assessed, and the effect of treatment determined using linear mixed model methodology. Results: The severity of periodontitis was associated with age, bodyweight, total globulins (Globs), Alanine aminotransferase, and IgG, and negatively associated with albumin, haemoglobin, haematocrit, and Aspartate aminotransferase (AST). Treatment significantly reduced IgG, total Globs, AST, and eosinophils, and increased cholesterol. Other leucocyte assays and plasma MDA concentrations were not affected by the treatment. Cats ate dry food faster 1 week after, than they did 1 week before treatment. Conclusions and clinical relevance: Although the clinical significance of these findings are unknown, we conclude that periodontitis is not simply a localized disease, but also impacts on systemic health and wellbeing.

Canine parvoviruses in New Zealand form a monophyletic group distinct from the viruses circulating in other parts of the world

Canine parvovirus 2 (CPV-2) is a well-recognized cause of acute haemorrhagic enteritis in dogs worldwide. The aim of the current study was to identify which CPV-2 subtypes circulate among dogs in New Zealand, and to investigate the evolutionary patterns of contemporary CPV-2 viruses. Faecal samples were collected from 79 dogs with suspected CPV-2 infection over the period of 13 months, and tested for the presence of CPV-2 DNA by PCR. Of 70 positive samples, 69 were subtyped as CPV-2a and one as CPV-2. A majority of CPV-2 positive samples were collected from unvaccinated or not-fully vaccinated puppies ≤6 months of age. The haplotype network produced from New Zealand CPV-2 sequences showed no structure when assessed based on location, vaccination status or age of the animals sampled. International haplotype network indicated that, unlike CPV-2 from other countries, the population of CPV-2 in New Zealand appeared to be monophyletic.