Metabolic basis for the essential nature of fatty acids and the unique dietary fatty acid requirements of cats

Dietary omega-3 fatty acids in the management of feline periodontal disease: What is the evidence?

Periodontal disease is an oral disorder with high prevalence in cats from 2 years of age, resulting from an inflammatory response against bacterial plaque. Treatment depends on the stage of the disease and may include dental scaling, local application of perioceutics, tissue regeneration and/or even tooth extraction and periodontal surgery. As multimodal therapy is often required, new strategies have been developed to improve the therapeutic response in these patients. Adjuvant use of omega-3 fatty acids has been reported in humans with periodontal disease, but the current evidence of its effect in companion animals, especially cats, is still considered to be scarce and conflicting. This review describes the state of the art regarding feline periodontal disease and seeks to clarify the potential effect of omega-3 fatty acids on its clinical management in light of the evidence available in the current literature.

A Comparison of Key Essential Nutrients in Commercial Plant-Based Pet Foods Sold in Canada to American and European Canine and Feline Dietary Recommendations

Simple Summary

Plant-based pet foods appear to be growing in popularity, but it is unclear how suitable these products are for dogs and cats, considering both species naturally consume diets rich in, or exclusively comprised of, animal tissues. Laboratory analyses of essential nutrients were performed on 26 plant-based diets available in Ontario, Canada in 2018, including 18 canine products (13 products labelled for adult maintenance, four for all life stages, one for puppy growth), 5 feline products (two for adult maintenance and three for all life stages), and 3 products labelled for both dogs and cats (one for adult maintenance and two for all life stages). The nutrient measurements were compared to industry standard nutrient profiles. Four products met the recommendations of the Association of American Feed Control Officials and one product the nutrient recommendations of the European Pet Food Industry Federation for adult dogs. No diets met recommended nutrient content for adult cats or growing puppies or kittens. Nutrients most commonly found to be insufficient were: sulfur amino acids, taurine, arachidonic acid, EPA and DHA, calcium phosphorus and vitamin D. These nutrients are all typically found in animal tissues, though non-animal sources are available, and require careful formulation or supplementation in products made without animal-derived ingredients. Compliance with Canadian labelling regulation and guidelines was poor. These problems do not appear to be exclusive to plant-based foods and have been demonstrated previously in commercially available animal-based products as well. This study demonstrates areas where manufacturers of plant-based pet foods must improve formulation and/or manufacturing practices to produce products appropriate for feeding cats and dogs.

Abstract

Plant-based foods intended for feeding dogs and cats are available in Canada, though few studies have examined the suitability of plant-based foods for dogs and cats. All commercial plant-based extruded and wet pet food products available in Ontario, Canada, in 2018 (n = 26) were acquired and analysed for energy, crude protein, crude fat, crude fibre, ash, amino acids, fatty acids, minerals and vitamins A, B₁₂, D₂ and D₃. Results were compared with recommendations of the Association of American Feed Control Officials (AAFCO) and the European Pet Food Industry Federation (FEDIAF). Thirteen products were labelled for adult canine maintenance, four for canine all life stages, one for puppy growth, two for adult feline maintenance, three for feline all life stages, one for adult maintenance of dogs and cats and two for all life stages of dogs and cats. Four products met AAFCO and one product met FEDIAF nutrient recommendations for canine maintenance. No diets met AAFCO or FEDIAF recommendations for feline maintenance or growth for either species. Nutrients most commonly found insufficient were: sulfur amino acids, taurine, arachidonic acid, EPA and DHA, calcium phosphorus and vitamin D. There were no nutrients unable to be provided from non-animal sources. Compliance with labelling guidelines was also poor, similar to other findings with commercial animal-based pet products. The results from this study indicate areas where producers of plant-based pet foods must improve to meet the industry recommended nutrient profiles and labelling requirements.

Therapeutic Effect of EPA/DHA Supplementation in Neoplastic and Non-neoplastic Companion Animal Diseases: A Systematic Review

BACKGROUND/AIM

The aim of this study is to identify and describe randomized controlled studies evaluating the therapeutic effect of EPA and DHA supplementation in companion animal diseases.

MATERIALS AND METHODS

A systematic search was conducted in PubMed database and the information collected was summarized and evaluated according to the risk of bias, using the revised Cochrane tool (RoB2).

RESULTS

Twenty-three studies were eligible for inclusion: twenty performed in dogs and three in cats. A therapeutic benefit was found in canine allergic dermatitis, haircoat disorder, keratoconjunctivitis sicca, valvular disease, and canine and feline osteoarthritis. Dogs diagnosed with chronic heart failure and lymphoma and cats with allergic dermatitis also seem to benefit from supplementation with omega-3 fatty acids, but studies with improved methodological quality are needed to strengthen this evidence.

CONCLUSION

EPA and DHA supplementation has proven benefits in the adjuvant treatment of various neoplastic and non-neoplastic diseases in dogs and cats.

A cross-sectional study of owner-reported health in Canadian and American cats fed meat- and plant-based diets

Background

Cats, being obligate carnivores, have unique dietary requirements for nutrients most commonly found in dietary ingredients of animal origin. As such, feeding a diet devoid of animal-derived ingredients has been postulated as a possible cause of nutrient imbalances and adverse health outcomes. A small proportion of cat owners feed strictly plant-based diets to the cats in their care, yet the health and wellness of cats fed these diets has not been well documented.

Results

A total of 1325 questionnaires were complete enough for inclusion. The only exclusion criterion was failure to answer all questions. Most cats, 65% (667/1026), represented in the survey were fed a meat-based diet and 18.2% (187/1026) were fed a plant-based diet, with the rest fed either a combination of plant-based with meat-based (69/1026, 6.7%) or indeterminable (103/1026, 10%). Cat age ranged from 4 months to 23 years, with a median of 7 years, and was not associated with diet type. No differences in reported lifespan were detected between diet types. Fewer cats fed plant-based diets reported to have gastrointestinal and hepatic disorders. Cats fed plant-based diets were reported to have more ideal body condition scores than cats fed a meat-based diet. More owners of cats fed plant-based diets reported their cat to be in very good health.

Conclusions

Cat owner perception of the health and wellness of cats does not appear to be adversely affected by being fed a plant-based diet. Contrary to expectations, owners perceived no body system or disorder to be at particular risk when feeding a plant-based diet to cats. This study collected information from cat owners and is subject to bias, as well as methodological limitations. Further research is warranted to determine if these results are replicable in a prospective investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02754-8.

Macronutrients in feline health

Dietary macronutrients include protein, fat, and carbohydrates. Current nutritional recommendations establish minimums but not maximums for protein and fat but not for carbohydrates; thus, commercial feline maintenance diets have a wide range of macronutrient distribution depending on manufacturer, ingredients, and processing. There is growing interest and discussion, however, in defining the ideal macronutrient composition of feline diets to maximize longevity and health. Current recommendations should be tailored to each patient based on age, body condition, presence of muscle mass atrophy, and the presence of disease.

Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication

Little is known about the genetic changes that distinguish domestic cat populations from their wild progenitors. Here we describe a high-quality domestic cat reference genome assembly and comparative inferences made with other cat breeds, wildcats, and other mammals. Based upon these comparisons, we identified positively selected genes enriched for genes involved in lipid metabolism that underpin adaptations to a hypercarnivorous diet. We also found positive selection signals within genes underlying sensory processes, especially those affecting vision and hearing in the carnivore lineage. We observed an evolutionary tradeoff between functional olfactory and vomeronasal receptor gene repertoires in the cat and dog genomes, with an expansion of the feline chemosensory system for detecting pheromones at the expense of odorant detection. Genomic regions harboring signatures of natural selection that distinguish domestic cats from their wild congeners are enriched in neural crest-related genes associated with behavior and reward in mouse models, as predicted by the domestication syndrome hypothesis. Our description of a previously unidentified allele for the gloving pigmentation pattern found in the Birman breed supports the hypothesis that cat breeds experienced strong selection on specific mutations drawn from random bred populations. Collectively, these findings provide insight into how the process of domestication altered the ancestral wildcat genome and build a resource for future disease mapping and phylogenomic studies across all members of the Felidae.

Failure of a dietary model to affect markers of inflammation in domestic cats

Background

Oxidative stress and inflammation can be altered by dietary factors in various species. However, little data are available in true carnivorous species such as domestic cats. As numerous anti-inflammatory and anti-oxidative additives become available and might be of use in cats with chronic low-grade inflammatory diseases, the current study aimed to develop a model of diet-induced inflammation by use of two opposite diets. It was hypothesized that a high fat diet enhanced in n-6 PUFA and with lower concentrations of antioxidants would evoke inflammation and oxidative stress in domestic cats.

Results

Sixteen healthy adult cats were allocated to two groups. One group received a moderate fat diet, containing pork lard and salmon oil (AA:(EPA + DHA) ratio 0.19) (MFn-3), while the other group was fed a high fat diet, containing pork lard and chicken fat (AA:(EPA + DHA) ratio 2.06) (HFn-6) for 12 weeks. Prior to and 2, 4, 6, 8, 10 and 12 weeks after starting the testing period, blood samples were collected. Erythrocytic fatty acid profile showed clear alterations in accordance to the dietary fatty acid profile. Serum thiobarbituric acid reactive substances was higher when fed MFn-3 compared to the HFn-6, suggesting augmented oxidative stress. This was associated with a reduced serum vitamin E status, as serum α-tocopherol concentrations were lower with MFn-3, even with higher dietary levels of vitamin E. Serum cytokine and serum amyloid A concentrations were not influenced by diet.

Conclusion

These results point towards a resistance of cats to develop dietary fat-induced inflammation, but also suggest a high susceptibility to oxidative stress when fed a fish oil-supplemented diet even with moderate fat level and additional vitamin E.

Comparison of inferred fractions of n-3 and n-6 polyunsaturated fatty acids in feral domestic cat diets with those in commercial feline extruded diets

OBJECTIVE

To compare presumed fatty acid content in natural diets of feral domestic cats (inferred from body fat polyunsatrated fatty acids content) with polyunsaturated fatty acid content of commercial feline extruded diets.

SAMPLE

Subcutaneous and intra-abdominal adipose tissue samples (approx 1 g) from previously frozen cadavers of 7 adult feral domestic cats trapped in habitats remote from human activity and triplicate samples (200 g each) of 7 commercial extruded diets representing 68% of market share obtained from retail stores.

PROCEDURES

Lipid, triacylglycerol, and phospholipid fractions in adipose tissue samples and ether extracts of diet samples were determined by gas chromatography of methyl esters. Triacylglycerol and phospholipid fractions in the adipose tissue were isolated by thin-layer chromatography. Diet samples were also analyzed for proximate contents.

RESULTS

For the adipose tissue samples, with few exceptions, fatty acids fractions varied only moderately with lipid fraction and site from which tissue samples were obtained. Linoleic, α-linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic acid fractions were 15.0% to 28.2%, 4.5% to 18.7%, 0.9% to 5.0%, < 0.1% to 0.2%, and 0.6% to 1.7%, respectively. As inferred from the adipose findings, dietary fractions of docosahexaenoic and α-linolenic acid were significantly greater than those in the commercial feline diets, but those for linoleic and eicosapentaenoic acids were not significantly different.

CONCLUSIONS AND CLINICAL RELEVANCE

The fatty acid content of commercial extruded feline diets differed from the inferred content of natural feral cat diets, in which dietary n-3 and possibly n-6 polyunsaturated fatty acids were more abundant. The impact of this difference on the health of pet cats is not known.

Potential adverse effects of omega-3 Fatty acids in dogs and cats

Fish oil omega-3 fatty acids, mainly eicosapentaenoic acid and docosahexaenoic acid, are used in the management of several diseases in companion animal medicine, many of which are inflammatory in nature. This review describes metabolic differences among omega-3 fatty acids and outlines potential adverse effects that may occur with their supplementation in dogs and cats with a special focus on omega-3 fatty acids from fish oil. Important potential adverse effects of omega-3 fatty acid supplementation include altered platelet function, gastrointestinal adverse effects, detrimental effects on wound healing, lipid peroxidation, potential for nutrient excess and toxin exposure, weight gain, altered immune function, effects on glycemic control and insulin sensitivity, and nutrient-drug interactions.