David G Thomas

Massey University · Institute of Veterinary, Animal and Biomedical Sciences

Smart capsules are developing at a tremendous pace with a promise to become effective clinical tools for the diagnosis and monitoring of gut health. This field emerged in the early 2000s with a successful translation of an endoscopic capsule from laboratory prototype to a commercially viable clinical device. Recently, this field has accelerated and...

Animal behaviour can be an indicator of health and welfare. Monitoring behaviour through visual observation is labour-intensive and there is a risk of missing infrequent behaviours. Twelve healthy domestic shorthair cats were fitted with triaxial accelerometers mounted on a collar and harness. Over seven days, accelerometer and video footage were c...

While captivity-related stress and the associated rise in baseline glucocorticoid (GC) concentrations have been linked to ovarian quiescence in some felid species, no study has examined the effects of elevated GC on oocyte quality. This study examined the effects of exogenous GC administration on the ovarian response and oocyte quality of domestic...

Simple Summary: The pet food industry is growing rapidly globally. Although new products continue to be developed, research into their palatability still largely uses traditional methods. Testing focuses on the amount of food consumed, but little consideration is given to why differences are observed and which ingredients are most important. This r...

Human gut microbiota can provide comprehensive information about the health of a host but the tools to collect microbiome samples are not currently available. A standalone wireless robotic capsule that has been developed in this study, collects the microbiota both from lumen (capsule surrounding) and intestinal wall (mucosa layer) for the first tim...

Elevated glucocorticoid (GC) concentrations associated with captivity-related stress have been linked to impaired testicular function and low sperm quality in felids, but direct physiological evidence is lacking. This study assessed the effects of exogenous GC treatment on felid testicular function using the domestic cat (Felis catus) as a model sp...

The gastrointestinal microbiome has a range of roles in the host, including the production of beneficial fermentation end products such as butyrate, which are typically associated with fermentation of plant fibres. However, domestic cats are obligate carnivores and do not require carbohydrates. It has been hypothesised that in the wild, collagenous...

Physical activity contributes up to 30% of the total daily energy expenditure of domestic cats (Felis catus) and, therefore, can play an important role in the prevention and reduction of obesity and may impact macronutrient digestibility. An age-related decline in physical activity in domestic cats has been observed, however, scientific data is sca...

Context The type of forage offered to horses varies in physical form, moisture content and nutrient quality, and these variables could affect the intake, passage rate and digestibility of the forage consumed. Aims To investigate the changes in passage rate of digesta through the gastrointestinal tract in horses fed four different forage-based diets...

Accurate and reliable monitoring of ovarian activity is challenging in many felids as current methods are either invasive or not amenable to real-time assessments. This 45-day study assessed whether accelerometry and infrared (IR) thermography can be used to address these limitations. Intact female domestic cats (n = 12) were given 0.088 mg kg⁻¹ da...

Domestic cats often need to be restrained for clinical procedures. One method that is commonly used to restrain cats is manual scruffing or pinch-induced behavioural inhibition (PIBI; i.e., clip restraint). However, few studies have evaluated its efficacy in cats. This study aims to evaluate the efficacy of PIBI in cats and determine if it declines...

Recent studies suggest that human gut microbiota can act as a bio-marker for human health. Also, it can function as a potential tool to understand stress and anxiety. However, the conventional tools have limitations in acquiring a sample of gut microbiota without contamination. In this work, an untethered robotic capsule prototype is developed, whi...

The management of competition horses in New Zealand often involves rotations of short periods of stall confinement and concentrate feeding, with periods of time at pasture. Under these systems, horses may undergo abrupt dietary changes, with the incorporation of grains or concentrate feeds to the diet to meet performance needs, or sudden changes in...

The aim of this review was to summarise the available literature on the effects of consuming raw red meat diets on the gastrointestinal microbiome of the cat and dog. In recent years, feeding raw meat diets to cat and dogs has increased, in part associated with trends in human nutrition for “natural” and “species-appropriate” diets. These diets ran...

Seasonal variation in the faecal microbiota of forage-fed horses was investigated over a 12-month period to determine whether the bacterial diversity fluctuated over time. Horses (n = 10) were maintained on pasture for one year, with hay supplemented from June to October. At monthly intervals, data were recorded on pasture availability and climate...

Using robotic capsules for assessing gut health has been an emerging field since the early 2000s with researchers attempting to perform diagnosis, monitoring and therapeutic functions inside the gut. The knowledge of peristaltic forces inside the intestine are crucial for designing the actuation mechanism of robotic capsules, however the impact of...

A significant population of microorganisms (bacteria, archae and fungi) live inside the gastrointestinal (GI) tract, and are collectively known as microbiota [1]. The microbiota contain lifelong information on the health of an individual and can assist in early diagnosis of diseases such as cancer, diabetes and obesity [2-3]. Microbiota can also he...

Reliable detection and monitoring of estrus and pregnancy is essential to the effective ex situ conservation of endangered felids. Here, we review the current methods used to detect estrus and pregnancy in felids and describe the advantages and limitations of each. A total of 194 felid-focused publications were reviewed. The methods used included b...

Background Human gut microbiota can provide lifelong health information and even influence mood and behaviour. We currently lack the tools to obtain a microbial sample, directly from the small intestine, without contamination. Methods Shape memory alloy springs are used in concentric configuration to develop an axial actuator. A novel design of sa...

The pet food industry continues to utilise large amounts of inedible meat components from the human food industry. Although used extensively in pet food formulations and as palatants, little is known about the palatability of individual meat components. The objectives of this study were to investigate the palatability of raw meat components commonl...

Felis catus papillomavirus type 2 (FcaPV-2) commonly infects the skin of domestic cats and has been associated with the development of skin cancer. In the present study, a FcaPV-2 virus-like particle (VLP) vaccine was produced and assessed for vaccine safety, immunogenicity, and impact on FcaPV-2 viral load. This is the first report of the use of a...

Commercial diets high in animal protein and fat are increasingly being developed for pets, however little is understood about the impacts of feeding such diets to domestic cats. The carbohydrate content of these diets is typically low, and dietary fibre is often not included. Dietary fibre is believed to be important in the feline gastrointestinal...

Bacterial taxa observed in faeces of domestic cats fed Kibble, Raw+Fibre and Raw diets according to a 21-day block cross-over design. (XLSX)

• Knowledge of reproductive biology is crucial to improving in situ and ex situ breeding programmes for felids. We reviewed the available literature (223 publications) on the reproductive biology of all 38 felid species. • We found that 78% of the publications (173) were focused on either or both the oestrous cycles (84) or ejaculate traits (92) of...

A 21‐day experiment was conducted to investigate the effects of wheat particle size, insoluble fibre source and whole wheat (WW) inclusion on the gizzard musculature, intestinal architecture and nutrient utilisation of broiler chickens. The following seven treatments, all in mash form, were tested: control diet using finely ground wheat (Fine); con...

Obesity is highly prevalent in pet cats (Felis silvestris catus) and is associated with several comorbidities, yet very little is understood about the early life risk factors. The aim of this study was to develop a mathematical model that describes growth in cats, to determine which early life variables were associated with being overweight in adul...

R codes for dataset intergration.

R codes for microbial analysis.

In humans, aging is associated with changes in the gastrointestinal microbiota; these changes may contribute to the age-related increase in incidence of many chronic diseases, including Type 2 diabetes. The life expectancies of cats are increasing, and they are also exhibiting the same types of diseases. While there are some studies investigating t...

Peripheral blood mononuclear cell (PBMC) gene expression microarray profiling is a minimally invasive tool used in human diet intervention studies. In this study, PBMC gene expression was determined in dogs fed kibble or raw red meat diets for 9 weeks to test the hypothesis that diet influences canine immune cell gene expression profiles. The two d...

Certain commercial horse feed supplements based on active yeast and its derivatives, and have been shown to improve digestion of feed (Medina et al , 2002), although this data is very limited and is mostly derived from studies in other species, such as pigs or cattle. Yeast-derived compounds are known to improve digestibility via different mechanis...

The increasing use of functional foods as a non-invasive way to modulate and optimise human immune system function is now beginning to transfer into the production animal and companion animal areas as owners search for alternative ways of maintaining and improving animal health. To date, dietary supplementation trials, primarily carried out in huma...

The diet of the domestic dog has changed significantly from that of its wolf ancestor, with to date only two studies having examined macronutrient self-selection in dogs. Whilst the first focused solely on protein intake, determining an intake of 30% metabolisable energy (ME), the second investigated dietary protein, fat and carbohydrate (PFC), ind...

Goats have a historical record of being productive and valuable to families and communities (Aziz 2010). Small ruminants, which include goats, still have an ‘unfulfilled’ potential despite the numbers of animals farmed and their distribution around the world (Anaeto et al. 2010). Pollot and Wilson (2009) concluded that goats deserve greater attenti...

The New Zealand goat industry is evolving and there is potential for expansion of its export products. The production and value of the New Zealand goat industry has been explored previously when the industry was in its infancy (Sheppard & O’Donnell 1979), at a time when Mohair production was seen to be ‘the most profitable goat farming enterprise’....

Goat farming in New Zealand has a lower profile compared to dairy, sheep and beef systems. The goat industry is small in New Zealand (Stafford & Prosser, 2016) and there has been limited consideration of the potential for the industry to expand (Shepard & O’Donnell, 1979). The environmental and commodity market constraints currently impacting pasto...

Objectives Felis catus papillomavirus type 2 (FcaPV-2) commonly infects the skin of domestic cats, and mounting evidence suggests that the virus could be involved in a subset of feline skin cancers. The reason why some cats develop FcaPV-2-induced disease and others do not is currently unknown. However, it has been shown that kittens in different l...

Obesity levels in cats are increasing and the main causative factor is higher energy intake v . energy expenditure over time. Therefore, altering energy expenditure by enhancing physical activity of the cat could be a strategy to reduce obesity. Hydrating commercial dry diets with water increased activity in cats; however, no study has compared thi...

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 direc...

A network plot of the first two canonical dimensions of regularised canonical correlation analysis of faecal 16S genomic DNA amplicon genus data Includes physical measurement and metabolomics data (0.6 cutoff) revealing Clostridiaceae as a central node in dogs fed both the meat and kibbled diets.

Correlation heat map Correlation heat map describing the associations between Clostridiaceae (Clostridium and Unclassified Clostridiaceae), Erysipelotrichaceae (Allobaculum, Catenibacterium, Holdemania, Turicibacter and Unclassified Erysipelotrichaceae) and Bacteriodaceae (Bacteroides) levels in dogs and physiological markers of intestinal function...

Schematic showing the study design, samples taken and statistical analysis

Variate plots of the first two canonical dimensions of canonical correlation analysis of faecal 16S genomic DNA amplicon data with physical measurement using shrinkage The first dimension separates diet well. The time points are not separated well in either dimension. Red text indicates dogs fed the kibble diet at 3, 6 or 9 weeks and black text ind...

Supplementary tables for key bacterial families ( Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae) are related to the digestion of protein and energy in dogs

Screenplot of canonical correlation analysis of faecal 16S genomic DNA amplicon data with physical measurement using shrinkage The first dimension has the highest canonical correlation.

The correlation circle plot of the first two canonical dimensions of canonical correlation analysis of faecal 16S genomic DNA amplicon data Includes physical measurement and metabolomics data using shrinkage showing a number of highly correlated parameters including positive correlation between Clostridiaceae and physical measurement data.

Scientific Reports 6 : Article number: 34668 10.1038/srep34668 ; published online: 23 November 2016 ; updated: 24 January 2017 The original version of this Article contained a typographical error in the title, where: “Pre- and post-weaning diet alters the faecal metagenome in the cat with differences vitamin and carbohydrate metabolism gene abundan...

Dietary format, and its role in pet nutrition, is of interest to pet food manufacturers and pet owners alike. The aim of the present study was to investigate the effects of pre- and post-weaning diets (kibbled or canned) on the composition and function of faecal microbiota in the domestic cat by shotgun metagenomic sequencing and gene taxonomic and...

Background: Bacterial urinary tract infections are uncommon in cats in general but the prevalence increases to 29% in older cats with comorbidities (Veterinary Clinical Pathology 2008, 37, 317; Journal of Feline Medicine & Surgery 2007, 9, 124; Veterinary Microbiology 2009, 136, 130). Frequently, the infections are subclinical. The clinical releva...

A cross-sectional study was conducted to describe and compare the body condition and morphometrics of Pony Club (PC) horses and ponies at two points in the year. Data were collected from a cohort of PC riders in spring (n=158) and autumn (n=155), with 73 repeat measurements across the two seasons. There were more ponies (68%, 164/240, wither-height...

Accelerometers (Actical® ‘Mini Mitter’ (MMA)) have been used to assess the activity of domestic cats (Felis catus), and have been validated against measures of observed activity in this species; however, previous validation trials have had very small sample sizes and have not considered inter-individual variation. The present study aimed to quantif...

Objective To assess the potential of a thermal carbon dioxide (CO2) laser to explore antinociception in pain-free cats.Study designExperimental, prospective, blinded, randomized study.AnimalsSixty healthy adult female cats with a (mean ± standard deviation) weight of 3.3 ± 0.6 kg.Methods Cats were systematically allocated to one of six treatments:...

This study aimed to determine the effects of supplemental Vit E and/or Se on selected parameters of the immune system of the cat. Nine diets were fed in a 3 × 3 factorial design with no supplementation (control (C)); and either moderate (M); or high (H) levels of Vit E (0, 225 or 450 mg/kg DM diet) and/or Se (0, 2 or 10 mg/kg DM diet) added to a co...

The aim of this study was to compare the effects of feeding two diets with different macronutrient proportions (high protein, low carbohydrate and low protein, high carbohydrate) on the digestibility and post-prandial endocrine responses of cats fed at maintenance levels, and to evaluate the effectiveness of the marginal ear vein prick technique fo...

The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet ("Group A"; n = 6) or pasture ("Group B"; n = 6) for three weeks prior to the study. After the Day 0 fae...

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 ener...

A cross-sectional survey was conducted to describe rider and horse demographics, and the feeding, health, and management of horses and ponies involved with Pony Clubs in New Zealand. An online survey collected information from members of the New Zealand Pony Clubs Association between 1st November 2012 and 31st January 2013. A total of 502 responden...

In humans and rodents, dietary hydroxyproline (hyp) and oxalate intake affect urinary oxalate (Uox) excretion. Whether Uox excretion occurs in cats was tested by feeding diets containing low oxalate (13 mg/100 g DM) with high (Hhyp-Lox), moderate (Mhyp-Lox), and low hyp (Lhyp-Lox) concentrations (3.8, 2.0, and 0.2 g/100 g DM, respectively) and low...

Cat food manufacturers spend a significant proportion of their research budget on food formulation and palatability. In this paper we propose an efficient and economic method of monitoring cat feeding behaviour during palatability trials. Instrumenting food bowls with load cells measures how much is eaten in each meal, and video records the interac...

Carbon dioxide (CO2) thermal lasers have previously been validated for the assessment of nociception in cats. This experiment sought to assess the potential impact of factors associated with age, sex, body weight and sterilisation upon nociceptive threshold as measured by latency to display a behavioural response. Cats (N = 113) were exposed to a C...

The effects of pre- (i.e., gestation and during lactation) and post-weaning diet on the composition of faecal bacterial communities and adipose expression of key genes in the glucose and insulin pathways were investigated in the cat. Queens were maintained on a moderate protein:fat:carbohydrate kibbled ("Diet A"; 35:20:28% DM; n = 4) or high protei...

Genistein and daidzein are isoflavones which are reported to influence the reproductive system in a variety of mammalian species. This pilot study aimed to determine if dietary isoflavones could potentially influence reproductive parameters in domestic cats, when consumed during the postnatal development period. Cats (n = 12) were maintained on eit...

The apparent total tract and ileal digestibility assays to measure AA absorption in commercial canine diets was compared in the present study. Five ileal cannulated dogs were fed 5 commercial dry canine foods selected to contain 19 to 30% CP in a 5 × 5 Latin square design. Ileal and total tract digestibility (apparent and standardized) of DM, OM, C...

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...

The effects of short-term (5-week) exposure to wet or dry diets on fecal bacterial populations in the cat were investigated. Sixteen mixed-sex, neutered, domestic short-haired cats (mean age = 6 years; mean bodyweight = 3.4 kg) were randomly allocated to wet or dry diets in a crossover design. Fecal bacterial DNA was isolated and bacterial 16S rRNA...

This study was conducted to examine the potential benefits of dietary supplementation on the feline immune system. Forty three cats (8 or 9 per group) were fed a low protein control diet (22.7% DM basis), the same diet supplemented with yeast-derived nucleotides, salmon oil or l-arginine or a commercial moist high protein diet (53.0% DM basis) for...

Some felid diets contain isoflavones but the metabolic capacity of cats towards isoflavones is relatively unknown, despite the understanding that isoflavones have divergent biological potential according to their metabolite end-products. The objective of this study was to determine the plasma metabolites detectable in domestic cats after exposure t...

Dietary isoflavones have been hypothesised to play a role in hepatic veno-occlusive disease in captive exotic felids, although empirical evidence is lacking. This study aimed to investigate the effect of long-term (>1 year) dietary genistein and daidzein exposure on the hepatic biochemistry and histology of domestic cats. Individual cats were asses...

A trial was conducted, using 12 mature thoroughbred horses in a cross-over design, to compare the protein and amino acid digestibility of dry lucerne chaff (LC) against a controlled fermented lucerne (CFL) product (HNF Fiber®; Fiber Fresh Feeds Ltd, Reporoa, New Zealand). Crude protein levels were higher in CFL compared to LC, and when individual a...

Genistein and daidzein are isoflavones which are reported to influence the reproductive system in a variety of mammalian species. This pilot study aimed to determine if dietary isoflavones could potentially influence reproductive tract histology or morphology in domestic cats, when consumed during the postnatal development period. Cats were maintai...

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...

There is little information known about the energy requirements of cats in temperature climates. Energy requirement of domestic short-haired cats was determined using three groups of mixed gender - old kept outside (approximately 9.9 years of age; 4.8 kg; n = 9), young kept outside (approximately 3.1 years of age; 3.9 kg; n = 8) or young kept insid...

This study was conducted to determine the possible application of mulberry silage as a functional feed in the feeding management of Hanwoo, Korean native cattle, for high quality beef production. Twenty Hanwoo steers in the last stage of fattening were randomly assigned to two groups with (MSS) or without (Control) supplemental mulberry silage. The...