Biology subjects

Gardner, D. S.

Publications and source records attributed to Gardner, D. S..

5 recordsLinked to original sources

bioRxiv2025

Lipid droplets in felid kidneys: prevalence and composition by lipidomics

An accepted and common phenotypic curiosity of Felidae is the presence of intracytoplasmic lipid droplets in renal proximal tubule epithelial cells (RPTEC), also frequently in urine (lipuria). Both outcomes are currently considered, and taught, as incidental - without obvious pathophysiological consequence. This contrasts markedly with clinical (human) medicine where lipid vacuoles in RPTEC are usually associated with metabolic or chronic disease, such as CKD. Despite domestic felids having a high incidence of CKD as they age, no study has fully characterised feline RPTEC lipid droplets in the context of CKD. Here, we first characterised the incidence of RPTEC lipid in domestic cat (with/without CKD or chronic interstitial nephritis) versus domestic dog and Scottish Wildcat, across a wide age range. Felids (domestic, wildcat) consistently had greater renal lipid content than dogs at all ages studied. Intracytoplasmic lipid extraction with chromatography, fatty acid characterisation and mass spectrometry-based lipidomics revealed unusual presence of a panoply of novel lipids found only in domestic cat: lipids were primarily modified (i.e. less polar) ether-soluble triacylglycerols including monoalkyldiacylglycerols (MADAGs) and other branched-chain fatty acids. We suggest common presence of such rare lipid species in tubular lipid droplets in domestic cat reflects an aspect of felid biology that parallels age-related disease prevalence, in particular, being associated with the aetiopathogenesis of chronic renal interstitial nephritis (CIN) - a hallmark of CKD in felids.

zoology↗

bioRxiv2025

A novel resistant starch supplement induced significant weight loss in obese/overweight dogs

ObjectivesTo evaluate whether a resistant-starch containing supplement administered for 30 days would induce significant weight loss and lower body condition score (BCS) in overweight/obese dogs, compared to placebo. Methods21 home-based dogs in Norway completed the study. Study population included 15 breeds of which n=11 were male and n=10 female, ages ranged from 3 - 10 years (Mean 6.7). Weight and BCS were recorded at baseline (Day 0) and after 30 days feeding supplement A ( active ingredient). Subsequently, after a 5-day wash-out period with no supplement, all dogs received supplement B ( placebo) for a further 30 days, when they were re-weighed and BCS scored. Owners and the veterinarian overseeing the study were blinded to content of supplements. ResultsThe resistant-starch-containing supplement led to statistically significant weight loss (0.45 {+/-} 0.57 kg, mean {+/-} 1SD; P = 0.002) with 17 of 21 dogs (77%) losing weight. A 0.5 unit reduction in BCS was noted (P = 0.009). Dogs lost some weight on placebo, but BCS did not change. Clinical significanceThis novel supplement containing resistant-starch, beta-glucan, alpha-lipoic acid and probiotic can be used to induce weight loss in overweight/obese dogs.

animal behavior and cognition↗

bioRxiv2025

Environmental Impacts of Dry Vegan Dog Food: A Comprehensive UK Analysis

IntroductionPet food production contributes substantially to global environmental pressures, driven largely by animal-derived ingredients. The current study quantified the environmental impacts of 31 commercially available dry dog foods purchased in the UK, categorised as plant-based, poultry-based, red meat-based (beef and lamb) and veterinary renal diets. MethodEnvironmental metrics including land use (m{superscript 2}/1000 kcal), greenhouse gas emissions (kg CO2eq/1000 kcal), acidifying emissions (g SO2eq/1000 kcal), eutrophying emissions (g PO3-eq/1000 kcal), and freshwater withdrawal (L/1000 kcal) were estimated using life cycle assessment datasets and adjusted for ingredient composition and energy density. Foods were additionally standardised to 100% moisture-adjusted content, and group differences were evaluated statistically. Results and discussionPlant-based diets demonstrated the lowest impacts across all measures. Poultry-based and veterinary diets showed intermediate profiles, while beef- and lamb-based foods exhibited substantially higher impacts. Beef-based diets required 101.12 m{superscript 2} land and emitted 31.16 kg CO2eq per 1000 kcal dry food, compared to 2.71 m{superscript 2} land and 2.79 kg CO2eq for plant-based. Beef-based foods generated 7.1-fold higher acidifying emissions and 16.4-fold higher eutrophying emissions, compared to plant-based foods. Lamb-based foods were the most freshwater intensive (677.01L/1000kcal), compared to plant-based (246.95L/1000kcal). Whilst moving to a circular food system has the potential to reduce environmental impact, current pet food manufacturing practices compete with human food supply and are not nutritionally necessary for dogs to thrive. These findings highlight a major opportunity to mitigate the environmental footprint of companion animal nutrition through reformulation towards higher inclusion of plant-based ingredients.

ecology↗

bioRxiv2024

Nutritional analysis of commercially available, complete plant- and meat-based dry dog foods in the UK

BackgroundAdoption of a plant-based diet is a popular lifestyle choice for many owners of canine companion animals. Increasingly, owners would like to feed their canine companions a similar diet. A plant-based dietary pattern has been reported to be associated with some micronutrient deficiencies. Complete dog foods are, by definition, supposed to be nutritionally replete in all macro- and micronutrients. Few studies have reported a full nutritional analysis of complete, dry plant-versus meat-based dog foods. MethodHere, 31 pet foods (n=19 meat-based, n=6 veterinary and n=6 plant-based) were analysed for total protein content and individual amino acids, fatty acids, major and trace elements, vitamin D and all B-vitamins. ResultsNutritional composition of meat and plant-based foods were similar, except for iodine and B-vitamins, which were lower in plant-based foods. The majority (66%) of veterinary diets with lower total protein by design, were also deficient in one or more essential amino acids. Isolated instances of non-compliance to nutritional guidelines were observed across all food-groups. Of the tested nutrients 55%, 16%, 24% and 100% of foods met all amino acid, mineral, B-vitamin, and vitamin D guidelines, respectively. ConclusionsAdopting a plant-based dietary pattern for your companion canine can provide nutritional adequacy with respect to the majority of macro- and micronutrients, but feeding supplemental iodine and B-vitamins should be considered. Veterinary diets, purposely low in crude protein, often have less than optimal essential amino acid composition. These data provide important new information for owners of companion canines being fed plant-based or veterinary diets.

zoology↗

bioRxiv2017

Mineral analysis of complete dog and cat foods in the UK and compliance with European guidelines

The mineral content of complete pet food is regulated to ensure health of the companion animal population. A comprehensive analysis of adherence to these regulatory guidelines has not been conducted. We measured mineral composition of a range of complete wet (n=97) and dry (n=80) canine and feline pet food sold in the UK to assess compliance with EU guidelines. While a majority of foods complied with [≥]8 of 11 guidelines (99% and 83% for dry and wet food, respectively), many failed to provide nutritional minimum (e.g. Cu, 20 % of wet food) or exceeded nutritional maximum (e.g. Se, 76% of wet food). Only 6% (6/97) of wet and 39% (34/80) of dry food were fully compliant. Some foods (20-30% of all analysed) had mineral imbalances such as not having the recommended balance of Ca:P (between 1:1 to 2:1). Foods with high fish content had high levels of undesirable metal elements such as arsenic. The study highlights broad non-compliance of a range of popular pet foods sold in the UK with EU guidelines (95% and 61% of wet and dry foods, respectively). If fed exclusively and over an extended period, a number of these pet foods could impact the general health of companion animals.

zoology↗