Nutritional risks to large-breed dogs: from weaning to the geriatric years

Birth weight, puppies' growth and health with limited-ingredient novel protein diet vs standard diet in late pregnancy

Great attention has been given in the last years to the protein source of dog food, and commercial limited-ingredient diets with a single protein are available also for late pregnancy. This work compared the effect of a fish-based limited ingredient diet (LID), and of a standard mixed-protein diet (Mixed), fed to the bitches from the last three weeks of pregnancy and to the puppies at weaning, on birth weight, growth and health of the puppies. From a breeder's records, the weight of 22 Lagotto Romagnolo (LR) and 10 Appenzeller Cattle Dog (ACD) bitches on the day of mating, and of their 199 puppies, were extracted. The effect of diet on puppies' weight on day 0, 6, 30 and 60 was analyzed, considering litter size and sex. The analyses were repeated on puppies' weights normalized on the relative dam's non-pregnant bodyweight. Birth weight was available for 146 puppies, 82 LR and 64 ACD. Median birth weight of LR puppies was 287.5 g (170-400 g); sex ratio was 1.11 (males/females, N = 80). Median birth weight of ACD puppies was 390 g (240-525 g); sex ratio 1.15 (males/females, N = 58). Diet did not significantly affect birth weight in both breeds; however, it showed a significant effect on normalized birth weights (LR, P = 0.016; ACD, P = 0.034), with higher values for LID. At day 30, ACD puppies showed significantly higher weights with the Mixed diet (P = 0.002), and, at day 60, diet significantly affected the normalized weight in both breeds (LR, P = 0.019; ACD, P = 0.001), with higher values for the Mixed type. LID may help the dam to invest the energy in the growth of her litter, however, the same diet resulted in lower puppies' weights around weaning, compared to the Mixed diet. Although our results should be confirmed with larger numbers of animals and more breeds, they set some points worth to be further investigated. The choice of a limited-ingredient single-protein diet can affect litter weight and weight at weaning. Whether, administered to dams and puppies, it can prevent later pathologies, like chronic gastrointestinal diseases or food allergies, is a field of research deserving full attention.

Spontaneous dog osteoarthritis - a One Medicine vision

Osteoarthritis (OA) is a global disease that, despite extensive research, has limited treatment options. Pet dogs share both an environment and lifestyle attributes with their owners, and a growing awareness is developing in the public and among researchers that One Medicine, the mutual co-study of animals and humans, could be beneficial for both humans and dogs. To that end, this Review highlights research opportunities afforded by studying dogs with spontaneous OA, with a view to sharing this active area of veterinary research with new audiences. Similarities and differences between dog and human OA are examined, and the proposition is made that suitably aligned studies of spontaneous OA in dogs and humans, in particular hip and knee OA, could highlight new avenues of discovery. Developing cross-species collaborations will provide a wealth of research material and knowledge that is relevant to human OA and that cannot currently be obtained from rodent models or experimentally induced dog models of OA. Ultimately, this Review aims to raise awareness of spontaneous dog OA and to stimulate discussion regarding its exploration under the One Medicine initiative to improve the health and well-being of both species.

Osteoarthritis occurs spontaneously in pet dogs, which often share environmental and lifestyle risk-factors with their owners. This Review aims to stimulate cooperation between medical and veterinary research under the One Medicine initiative to improve the welfare of dogs and humans.

Dogs have many analogous spontaneous diseases that result in end-stage osteoarthritis (OA).

Inbreeding and the predisposition of certain dog breeds for OA enable easier identification of candidate genetic associations than in outbred humans.

Dog OA subtypes offer a potential stratification rationale for aetiological differences and alignment to analogous human OA phenotypes.

The relatively compressed time course of spontaneous dog OA offers longitudinal research opportunities.

Collaboration with veterinary researchers can provide tissue samples from early-stage OA and opportunities to evaluate new therapeutics in a spontaneous disease model.

Awareness of the limitations and benefits of using clinical veterinary patients in research is important.

Pet Food Quality Assurance and Safety and Quality Assurance Survey within the Costa Rican Pet Food Industry

Costa Rican animal feed production is continually growing, with approximately 1,238,243 metric tons produced in 2018. Production-wise, pet cat and dog food are in fifth place (about 41,635 metric tons per year) amongst animal feeds, and it supplies up to 90% of the national market. Pet food production has increased as a response to the increase in the population of dogs and cats in Costa Rica, where 50.5% of households own at least one dog and indicates more responsible ownership in terms of feeding pets. Part of the process of making dry pet food involves a thermal process called extrusion, which is capable of eliminating the microbial load. However, extrusion can compromise nutritional quality to some extent by denaturing proteins, oxidizing lipids, and reducing digestibility. The objective of this study was to evaluate the quality and safety of dry pet food and to assess the effect of the extrusion process on digestibility and the quality of proteins, amino acids, and fatty acids. Pet food samples were collected before and after extrusion and were used to evaluate Good Manufacturing Practices (GMP), based on Central American Technical Regulation (RTCA 65.05.63:11). In general terms, weaknesses in infrastructure, documentary evidence, and post-process practices were observed in two Costa Rican feed manufactories. Feed safety was surveyed through the analysis of Salmonella spp., Escherichia coli, Listeria spp., Staphylococcus aureus, aerobic mesophilic microorganisms, fungi, and yeasts counts. The extrusion process effectively reduced pathogenic microorganisms, and showed no effect on the digestibility of dog food (p = 0.347), however, it could reduce the availability of some nutrients (e.g., amino acids, fatty acids). Furthermore, a retrospective diagnosis was made for puppy food (n = 68), dog food (n = 158), and cat food (n = 25), to evaluate the history of nutritional quality and safety. Finally, it can be confirmed that the correct implementation of GMP allows feed manufacturers to deliver a product of optimum texture, smell, nutritional composition, and safety.

The canine gut microbiome is associated with higher risk of gastric dilatation-volvulus and high risk genetic variants of the immune system

BACKGROUND

Large and giant dog breeds have a high risk for gastric dilatation-volvulus (GDV) which is an acute, life-threatening condition. Previous work by our group identified a strong risk of GDV linked to specific alleles in innate and adaptive immune genes. We hypothesize that variation in the genes of the immune system act through modulation of the gut microbiome, or through autoimmune mechanisms, or both, to predispose dogs to this condition. Here, we investigate whether differences in the canine fecal microbiome are associated with GDV and are linked to previously identified risk alleles.

METHODOLOGY/PRINCIPLE FINDINGS

Fecal samples from healthy Great Danes (n = 38), and dogs with at least one occurrence of GDV (n = 37) were collected and analyzed by paired-end sequencing of the 16S rRNA gene. Dietary intake and temperament were estimated from a study-specific dietary and temperament questionnaire. Dogs with GDV had significantly more diverse fecal microbiomes than healthy control dogs. Alpha diversity was significantly increased in dogs with GDV, as well as dogs with at least one risk allele for DRB1 and TRL5. We found no significant association of dietary intake and GDV. Dogs with GDV showed a significant expansion of the rare lineage Actinobacteria (p = 0.004), as well as a significantly greater abundance of Firmicutes (p = 0.004) and a significantly lower abundance of Bacteroidetes (p<0.004). There was a significant difference in the abundance of 10 genera but after correction for multiple comparisons, none were significant. Bacterial phyla were significantly different between controls and dogs with GDV and at least one risk allele for DRB1 and TRL5. Actinobacteria were significantly higher in dogs with GDV and with one risk allele for DRB1 and TLR5 but not DLA88 genes. Furthermore, Collinsella was significantly increased in dogs with at least one risk allele for DRB1 and TLR5. Logistic regression showed that a model which included Actinobacteria, at least one risk allele,and temperament, explained 29% of the variation in risk of GDV in Great Danes.

CONCLUSIONS

The microbiome in GDV was altered by an expansion of a minor lineage and was associated with specific alleles of both innate and adaptive immunity genes. These associations are consistent with our hypothesis that immune genes may play a role in predisposition to GDV by altering the gut microbiome. Further research will be required to directly test the causal relationships of immune genes, the gut microbiome and GDV.

Associations between gastric dilatation-volvulus in Great Danes and specific alleles of the canine immune-system genes DLA88, DRB1, and TLR5

OBJECTIVE To determine whether specific alleles of candidate genes of the major histocompatibility complex (MHC) and innate immune system were associated with gastric dilatation-volvulus (GDV) in Great Danes. ANIMALS 42 healthy Great Danes (control group) and 39 Great Danes with ≥ 1 GDV episode. PROCEDURES Variable regions of the 2 most polymorphic MHC genes (DLA88 and DRB1) were amplified and sequenced from the dogs in each group. Similarly, regions of 3 genes associated with the innate immune system (TLR5, NOD2, and ATG16L1), which have been linked to inflammatory bowel disease, were amplified and sequenced. Alleles were evaluated for associations with GDV, controlling for age and dog family. RESULTS Specific alleles of genes DLA88, DRB1, and TLR5 were significantly associated with GDV. One allele of each gene had an OR > 2 in the unadjusted univariate analyses and retained a hazard ratio > 2 after controlling for temperament, age, and familial association in the multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE The 3 GDV-associated alleles identified in this study may serve as diagnostic markers for identification of Great Danes at risk for GDV. Additional research is needed to determine whether other dog breeds have the same genetic associations. These findings also provided a new target for research into the etiology of, and potential treatments for, GDV in dogs.

Evaluating oxidative stress, serological- and haematological status of dogs suffering from osteoarthritis, after supplementing their diet with fish or corn oil

Background

Oxidative stress plays an important role in the pathogenesis of disease, and the antioxidant physiological effect of omega-3 from fish oil may lead to improvement of canine spontaneous osteoarthritis (OA).

Methods

In this prospective randomized, controlled, double-blinded study, we assessed haematological and biochemical parameters in dogs with OA following supplementation with either a concentrated omega-3 deep sea fish oil product or corn oil. Blood samples from 77 client-owned dogs diagnosed as having OA were taken before (baseline) and 16 weeks after having orally ingested 0.2 ml/Kg bodyweight/day of deep sea fish oil or corn oil. Circulating malondialdehyde (MDA), glutathione (GSH), non-transferrin bound iron (NTBI), free carnitine (Free-Car), 8-hydroxy-2-deoxyguanosine (8-OH-dG), and serum fatty acids, haemograms and serum biochemistry were evaluated. Differences within and between groups from baseline to end, were analysed using repeated samples T-test or Wilcoxon rank test and independent samples T-test or a Mann-Whitney test.

Results

Supplementation with fish oil resulted in a significant reduction from day 0 to day 112 in MDA (from 3.41 ± 1.34 to 2.43 ± 0.92 μmol/L; P < 0.001) and an elevation in Free-Car (from 18.18 ± 9.78 to 21.19 ± 9.58 μmol/L; P = 0.004) concentrations, whereas dogs receiving corn oil presented a reduction in MDA (from 3.41 ± 1.34 to 2.41 ± 1.01 μmol/L; P = 0.001) and NTBI (from −1.25 ± 2.17 to −2.31 ± 1.64 μmol/L; P = 0.002). Both groups showed increased (albeit not significantly) GSH and 8-OH-dG blood values. Dogs supplemented with fish oil had a significant reduction in the proportions of monocytes (from 3.84 ± 2.50 to 1.77 ± 1.92 %; P = 0.030) and basophils (from 1.47 ± 1.22 to 0.62 ± 0.62 %; P = 0.012), whereas a significant reduction in platelets counts (from 316.13 ± 93.83 to 288.41 ± 101.68 × 10⁹/L; P = 0.029), and an elevation in glucose (from 5.18 ± 0.37 to 5.32 ± 0.47 mmol/L; P = 0.041) and cholesterol (from 7.13 ± 1.62 to 7.73 ± 2.03 mmol/L; P = 0.011) measurements were observed in dogs receiving corn oil.

Conclusions

In canine OA, supplementation with deep sea fish oil improved diverse markers of oxidative status in the dogs studied. As corn oil also contributed to the reduction in certain oxidative markers, albeit to a lesser degree, there was no clear difference between the two oil groups. No clinical, haematological or biochemical evidence of side effects emerged related to supplementation of either oil. Although a shift in blood fatty acid values was apparent due to the type of nutraceutical product given to the dogs, corn oil seems not to be a good placebo.

Effect of question design on dietary information solicited during veterinarian-client interactions in companion animal practice in Ontario, Canada

OBJECTIVE

To establish the types of initial questions used by veterinarians in companion animal practice to solicit nutritional history information from owners of dogs and cats, the dietary information elicited, and the relationship between initial question-answer sequences and later nutrition-related questions.

DESIGN

Cross-sectional qualitative conversation analytic study.

SAMPLE

98 appointments featuring 15 veterinarians drawn from an observational study of 284 videotaped veterinarian-client-patient visits involving 17 veterinarians in companion animal practices in eastern Ontario, Canada.

PROCEDURES

Veterinarian and client talk related to patient nutrition was identified and transcribed; conversation analysis was then used to examine the orderly design and details of talk within and across turns. Nutrition-related discussions occurred in 172 visits, 98 of which contained veterinarian-initiated question-answer sequences about patient nutritional history (99 sequences in total, with 2 sequences in 1 visit).

RESULTS

The predominant question format used by veterinarians was a what-prefaced question asking about the current content of the patient's diet (75/99). Overall, 63 appointments involved a single what-prefaced question in the first turn of nutrition talk by the veterinarian (64 sequences in total). Dietary information in client responses was typically restricted to the brand name, the subtype (eg, kitten), or the brand name and subtype of a single food item. When additional diet questions were subsequently posed, they typically sought only clarification about the food item previously mentioned by the client.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that question design can influence the accuracy and completeness of a nutritional history. These findings can potentially provide important evidence-based guidance for communication training in nutritional assessment techniques.

A survey of pet feeding practices of dog owners visiting a veterinary practice in Colombo, Sri Lanka

In Sri Lanka, home‐cooked diets are often fed due to the cost and poor availability of commercial diets. Milk has traditionally been a popular food to give to dogs in this country. There is a recent perceived increase in the number of owners choosing commercial diets for their pets. This study aimed to determine how dog owners visiting a single veterinary practice in Colombo fed their pets. We hoped that this would help achieve a general understanding of pet feeding practices in Sri Lanka and gain some basic demographic information on the owned dog population. The study was conducted via questionnaires distributed to pet owners visiting a first opinion and referral practice in Colombo. Hundred questionnaires were collected and analysed, 69% of study dogs were neutered, 42% of dogs were fed only home‐cooked food, while 18% were fed only commercial food. About 40% of dogs were fed a mixture of commercial and home‐cooked food, 49% of dogs were fed milk as a separate meal in addition to their normal diet and 57% of dogs received dietary supplements. Dogs consuming commercial food for more than half their intake were no less likely (P = 0.75) to receive dietary supplements than dogs fed homemade food for more than half their diet. This study provides some basic information regarding the feeding practices and demographics of the owned dog population in one Sri Lankan city, Colombo, highlighting some areas of concern.

Nutritional concepts for the veterinary practitioner

Although veterinary practitioners know that nutrition can make a difference in the health and recovery from disease or illness in dogs and cats, they may feel poorly equipped to provide unbiased information on nutrition. This article provides information about evaluating and recommending diets and interpreting a pet food label to allow for comparisons among pet foods and discussion about how to do a nutritional assessment. It provides an example of how nutritional assessment and recommendation were successfully introduced into a busy private practice. Finally, some of the myths and misperceptions about nutrition are discussed with information provided from evidence-based research.

A retrospective study of gastric dilatation and gastric dilatation and volvulus in working farm dogs in New Zealand

AIMS

To present findings from a case series of gastric dilatation (GD) or gastric dilatation and volvulus (GDV) in working farm dogs in New Zealand that were examined at veterinary clinics, and to identify possible risk factors for GD or GDV in working farm dogs in New Zealand using a case-control study.

METHODS

This retrospective study included a case-series and a case-control study. The case series analysed information from 62 case records of GD or GDV in working farm dogs seen between August 2004 and September 2009 at 13 veterinary clinics throughout New Zealand. Cases were classified as GD or GDV if the diagnosis was confirmed by radiography, surgery or post-mortem examination. Details of history and treatment, as well as outcomes, were obtained for each case. For the case-control study, records of 41 working farm dogs with GD or GDV (cases) seen between April 2008 and April 2009, and 82 working farm dogs examined because of trauma over the same period and in the same 13 clinics (controls), were used to model the risk factors for GD or GDV.

RESULTS

From the case-series study, 40/62 (65%) cases of GD or GDV that were examined and treated at the veterinary clinics returned to work. Of the 41 dogs where the gastric contents were recorded, 25 (61%) had predominantly food or bones in the stomach, and 26/27 dogs had a history of having eaten meat, bones or scavenged a carcass. The case-control study showed that the significant risk factors for GD or GDV, compared with control dogs presenting with trauma, were breed, age and season. The odds that a case of GD or GDV was a Huntaway, after adjusting for age and season, was 19 times higher than the odds a control was a Huntaway. Gender and bodyweight were not identified as risk factors.

CONCLUSIONS AND CLINICAL RELEVANCE

A high proportion of farm working dogs with GD or GDV were successfully treated by veterinarians. The risk of a case of GD or GDV being a Huntaway was significantly higher than for a dog presenting as a trauma case. However the influences of the season of the year, climatic factors and nutritional factors on the pathogenesis need to be identified before adequate preventative measures can be recommended.

Age-related cataract in dogs: a biomarker for life span and its relation to body size

Clinical data from 72 dog breeds of varying size and life expectancy were grouped according to breed body mass and tested for prevalence at ages 4 to 5, ages 7 to 10, and lifetime incidence of non-hereditary, age-related cataract (ARC). The incidence of ARC was found to be directly related to the relative life expectancies in the breed groups: The smallest dog breeds had a lower ARC prevalence between ages 4 and 5 than mid-size breeds and these, in turn, a lower prevalence than the giant breeds. A similar sequence was evident for ages 7 to 10 and for overall lifetime incidence of ARC. These differences became more significant when comparing small and giant breeds only. We could also confirm the inverse relationship between body size and life expectancy in these same sets of dog breeds. Our results show that body size, life expectancy, and ARC incidence are interrelated in dogs. Given that ARC has been shown to be at least partially caused by oxidative damage to lens epithelial cells and the internal lens, we suggest that it can be considered not only as a general biomarker for life expectancy in the canine and possibly other species, but also for the systemic damages produced by reactive oxygen species. This suggests new approaches to examine the gene expression pathways affecting the above-noted linkages.

Comparative rheumatology: what can be learnt from naturally occurring musculoskeletal disorders in domestic animals?

Examples of naturally occurring musculoskeletal disorders are extremely common in veterinary species and provide a valuable comparative research resource, which can provide compelling comparative data on the aetiopathogenesis and treatment of many common human musculoskeletal diseases. In particular, orthopaedic diseases are a common morbidity in both dogs and horses. In this review, we give an overview of the common musculoskeletal diseases encountered in these species: for instance, tendon and ligament injuries, arthropathies and stress fractures, as well as an insight into the basic biology of these conditions. In doing so, we aim to demonstrate the similarities and differences between these disorders and similar conditions in man.