Massey Research Online - Browsing by Author "Thomas DG"

Browsing by Author "Thomas DG"

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Comparison of gastrointestinal transit times in stabled Thoroughbred horses fed freshly cut pasture and three conserved forage-based diets
(CSIRO Publishing, 2022-07) Fernandes KA; Rogers CW; Gee EK; Fitch G; Bolwell CF; Kittelmann S; Bermingham EN; Thomas DG
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 (diet effect). Methods: Thoroughbred mares (n = 6) were stabled in loose boxes for 6 weeks. During Weeks 1, 3 and 5 (washout periods), all horses were fed freshly cut pasture, either in restricted quantities (Week 1) or ad libitum (Weeks 3 and 5). Using a 3 × 3 Latin square design during Weeks 2, 4 and 6, each pair of horses was abruptly transitioned to one of three conserved forage-based diets (chopped ensiled forage fed exclusively or with oats, or perennial ryegrass hay with oats) fed ad libitum. At the beginning of each week, indigestible polyethylene markers (n = 200) were administered to the horses via a nasogastric tube, followed immediately by transition to the new diet. Key results: There was a significant diet effect on the daily dry-matter intake of feed (P < 0.0001), percentage of time spent eating (P < 0.001), frequency of voiding faeces (P < 0.05) and quantity of faeces voided (P < 0.0001). There was a significant horse effect on the daily dry-matter intake of feed (P < 0.0001) and quantity of faeces voided (P < 0.0001), but no differences in the percentage of time spent eating or the frequency of voiding faeces. There were significant diet and horse effects on the time to recovery of the first marker in the faeces (P < 0.01 and P < 0.01 respectively) and the mean retention time of markers in the gastrointestinal tract (P < 0.05 and P < 0.001 respectively). Mean retention time was negatively correlated with feed intake and quantity of faeces voided (r2 =-0.51 and r2 =-0.64 respectively). Conclusions: Longer mean retention time was associated with a greater fibre content in the diet and a restricted feed supply, thus supporting the hypothesis that horses alter mean retention time on the basis of a nutrient absorption optimisation model. Implications: Feed composition, but also the quantities offered, may alter measurement of apparent feed digestibility in horses.
Development of a Robotic Capsule for in vivo Sampling of Gut Microbiota
(Institute of Electrical and Electronics Engineers, 2022-10-01) Rehan M; Al-Bahadly I; Thomas DG; Avci E
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 time. First, a two-way shape memory alloy (SMA) spring actuation system was developed by tackling the high-drain current requirement of SMAs. The actuator can produce up to 800 mN force that was sufficient to collect samples. Second, successful encapsulation of the collected sample to avoid contamination was realised by testing 3 main sealing materials. Third, the robotic capsule was tested in a gut simulator that mimics in-vivo environment to ensure successful and safe travel of the capsule along the gastrointestinal tract. Finally an in vitro experimental setup that keeps an intestine alive for 6 hours was used to optimise the sample collection. The capsule collected 128 μL and 107 μL samples (which are sufficient quantities for microbiome analysis) from duodenual and ileal tissues of a sheep. The proposed robotic capsule has a potential to become a vital apparatus for clinicians to sample human and animal gut in the future.
Dietary format alters fecal bacterial populations in the domestic cat (Felis catus)
(John Wiley and Sons, 2013) Bermingham EN; Young W; Kittelmann S; Kerr KR; Swanson KS; Roy NC; Thomas DG
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 gene amplicons generated and analyzed by 454 Titanium pyrosequencing. Cats fed dry diets had higher abundances (P < 0.05) of Actinobacteria (16.5% vs. 0.1%) and lower abundances of Fusobacteria (0.3% vs. 23.1%) and Proteobacteria (0.4% vs. 1.1%) compared with cats fed the wet diet. Of the 46 genera identified, 30 were affected (P < 0.05) by diet, with higher abundances of Lactobacillus (31.8% vs. 0.1%), Megasphaera (23.0% vs. 0.0%), and Olsenella (16.4% vs. 0.0%), and lower abundances of Bacteroides (0.6% vs. 5.7%) and Blautia (0.3% vs. 2.3%) in cats fed the dry diet compared with cats fed the wet diet. These results demonstrate that short-term dietary exposure to diet leads to large shifts in fecal bacterial populations that have the potential to affect the ability of the cat to process macronutrients in the diet.
Drivers of Palatability for Cats and Dogs-What It Means for Pet Food Development
(MDPI (Basel, Switzerland), 2023-03-23) Watson PE; Thomas DG; Bermingham EN; Schreurs NM; Parker ME; Biagi G
The pet food industry is an important sector of the pet care market that is growing rapidly. Whilst the number of new and innovative products continues to rise, research and development to assess product performance follows traditional palatability methodology. Pet food palatability research focuses on the amount of food consumed through use of one-bowl and two-bowl testing, but little understanding is given to why differences are observed, particularly at a fundamental ingredient level. This review will highlight the key differences in feeding behaviour and nutritional requirements between dogs and cats. The dominant pet food formats currently available and the ingredients commonly included in pet foods are also described. The current methods used for assessing pet food palatability and their limitations are outlined. The opportunities to utilise modern analytical methods to identify complete foods that are more palatable and understand the nutritional factors responsible for driving intake are discussed.
Felis catus papillomavirus type 2 virus-like particle vaccine is safe and immunogenic but does not reduce FcaPV-2 viral loads in adult cats
(Elsevier BV, 2019-07) Thomson NA; Howe L; Weidgraaf K; Thomas DG; Young V; Ward VK; Munday JS
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 papillomavirus VLP vaccine in domestic cats. The FcaPV-2 VLP vaccine was given to ten adult cats that were naturally infected with FcaPV-2, and a further ten naturally infected cats were sham vaccinated as a control group. The rationale for vaccinating cats already infected with the virus was to induce neutralizing antibody titers that could prevent reinfection of new areas of skin and reduce the overall viral load, as has been demonstrated in other species. Reducing the overall FcaPV-2 viral load could reduce the risk for subsequent PV-associated cancer. The vaccine in this study was well-tolerated, as none of the cats developed any signs of local reaction or systemic illness. In the treatment group, the geometric mean anti-papillomavirus endpoint antibody titers increased significantly following vaccination from 606 (95% CI 192-1913) to 4223 (2023-8814), a 7.0-fold increase, although the individual antibody response varied depending on the level of pre-existing antibodies. Despite the immunogenicity of the vaccine, there was no significant change in FcaPV-2 viral load in the treatment group compared to the control group, over the 24 week follow-up period. A possible reason is that FcaPV-2 was already widespread in the basal skin layer of these adult cats and so preventing further cells from becoming infected had no impact on the overall viral load. Therefore, these results do not support the use of a FcaPV-2 VLP vaccine to reduce the risk for PV-associated cancer in cats in which FcaPV-2 infection is already well established. However, these results justify future studies in which the vaccine is administered to younger cats prior to FcaPV-2 infection becoming fully established.
In Vitro Assessment of Hydrolysed Collagen Fermentation Using Domestic Cat (Felis catus) Faecal Inocula
(MDPI (Basel, Switzerland), 2022-02-17) Butowski CF; Thomas DG; Cave NJ; Bermingham EN; Rosendale DI; Hea S-Y; Stoklosinski HM; Young W; Ebani VV
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 parts of prey-the so-called animal-derived fermentable substrates (ADFS) such as tendons and cartilage-may be fermented by the cat's gastrointestinal microbiome. However, little research has been conducted on ADFS in the domestic cat. Faecal inoculum was obtained from domestic cats either consuming a high carbohydrate (protein:fat:carbohydrate ratio of 35:20:28 (% dry matter basis)) or high protein (protein:fat:carbohydrate ratio of 75:19:1 (% dry matter basis)) diet. ADFS (hydrolysed collagen, cat hair, and cartilage) were used in a series of static in vitro digestions and fermentations. Concentrations of organic acids and ammonia were measured after 24 h of fermentation, and the culture community of microbes was characterised. The type of inoculum used affected the fermentation profile produced by the ADFS. Butyrate concentrations were highest when hydrolysed collagen was fermented with high protein inoculum (p < 0.05). In contrast, butyrate was not detectable when hydrolysed collagen was fermented in high carbohydrate inoculum (p < 0.05). The microbiome of the domestic cat may be able to ferment ADFS to provide beneficial concentrations of butyrate.
Nutritional needs and health outcomes of ageing cats and dogs: is it time for updated nutrient guidelines?
(Oxford University Press on behalf of the American Society of Animal Science, 2024-06-20) Bermingham EN; Patterson KA; Shoveller AK; Fraser K; Butowski CF; Thomas DG
Implications • While cats are classed as senior at 10 years of chronological age, physiological and health changes occur from 8 years of age and it appears that diet may influence the ageing process. • Dogs are classed as senior at 12 years for smaller dogs and 10 years for larger breeds. Due to differences in longevity associated with breed size a definite age that dogs start to experience changes is difficult to establish. • Despite our pets ageing, living in extreme cases to 30 + years, there are no explicit nutritional guidelines for feeding ageing animals. Increased scientific knowledge around the specific nutritional requirements of ageing cats and dogs is required. • Many of the underlying physiological processes (e.g., immune function) and age-associated health conditions (e.g., cognitive decline) respond to nutritional intervention. This suggests that nutritional and regulatory guidelines, should consider recommendations for ‘senior+’ pets. • Due to the unique nutritional requirements of cats and dogs, more specific knowledge around the mechanisms of ageing is required.
Resilience of Faecal Microbiota in Stabled Thoroughbred Horses Following Abrupt Dietary Transition between Freshly Cut Pasture and Three Forage-Based Diets
(MDPI (Basel, Switzerland), 2021-09-06) Fernandes KA; Rogers CW; Gee EK; Kittelmann S; Bolwell CF; Bermingham EN; Biggs PJ; Thomas DG; Costa M
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 type of forage fed in response to a lack of fresh or conserved forage. Abrupt changes in dietary management are a risk factor for gastrointestinal (GI) disturbances, potentially due to the negative effects observed on the population of GI microbiota. In the present study, the faecal microbiota of horses was investigated to determine how quickly the bacterial communities; (1) responded to dietary change, and (2) stabilised following abrupt dietary transition. Six Thoroughbred mares were stabled for six weeks, consuming freshly cut pasture (weeks 1, 3 and 5), before being abruptly transitioned to conserved forage-based diets, both offered ad libitum. Intestinal markers were administered to measure digesta transit time immediately before each diet change. The conserved forage-based diets were fed according to a 3 × 3 Latin square design (weeks 2, 4 and 6), and comprised a chopped ensiled forage fed exclusively (Diet FE) or with whole oats (Diet FE + O), and perennial ryegrass hay fed with whole oats (Diet H + O). Faecal samples were collected at regular intervals from each horse following the diet changes. High throughput 16S rRNA gene sequencing was used to evaluate the faecal microbiota. There were significant differences in alpha diversity across diets (p < 0.001), and a significant effect of diet on the beta diversity (ANOSIM, p = 0.001), with clustering of samples observed by diet group. There were differences in the bacterial phyla across diets (p < 0.003), with the highest relative abundances observed for Firmicutes (62 - 64%) in the two diets containing chopped ensiled forage, Bacteroidetes (32-38%) in the pasture diets, and Spirochaetes (17%) in the diet containing hay. Major changes in relative abundances of faecal bacteria appeared to correspond with the cumulative percentage of intestinal markers retrieved in the faeces as the increasing amounts of digesta from each new diet transited the animals. A stable faecal microbiota profile was observed in the samples from 96 h after abrupt transition to the treatment diets containing ensiled chopped forage. The present study confirmed that the diversity and community structure of the faecal bacteria in horses is diet-specific and resilient following dietary transition and emphasised the need to have modern horse feeding management that reflects the ecological niche, particularly by incorporating large proportions of forage into equine diets.
Seasonal Variation in the Faecal Microbiota of Mature Adult Horses Maintained on Pasture in New Zealand
(MDPI (Basel, Switzerland), 2021-08-04) Fernandes KA; Gee EK; Rogers CW; Kittelmann S; Biggs PJ; Bermingham EN; Bolwell CF; Thomas DG; Costa M
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 (collected continuously and averaged on monthly basis), pasture and hay samples were collected for nutrient analysis, and faecal samples were collected from all horses to investigate the diversity of faecal microbiota using next-generation sequencing on the Illumina MiSeq platform. The alpha diversity of bacterial genera was high in all samples (n = 118), with significantly higher Simpson's (p < 0.001) and Shannon-Wiener (p < 0.001) diversity indices observed during the months when horses were kept exclusively on pasture compared to the months when pasture was supplemented with hay. There were significant effects of diet, season, and month (ANOSIM, p < 0.01 for each comparison) on the beta diversity of bacterial genera identified in the faeces. While there was some inter-horse variation, hierarchical clustering of beta diversity indices showed separate clades originating for samples obtained during May, June, and July (late-autumn to winter period), and January, February, and March (a period of drought), with a strong association between bacterial taxa and specific nutrients (dry matter, protein, and structural carbohydrates) and climate variables (rainfall and temperature). Our study supports the hypothesis that the diversity and community structure of the faecal microbiota of horses kept on pasture varied over a 12-month period, and this variation reflects changes in the nutrient composition of the pasture, which in turn is influenced by climatic conditions. The findings of this study may have implications for grazing management and the preparation of conserved forages for those horses susceptible to perturbations of the hindgut microbiota.
Smart capsules for sensing and sampling the gut: status, challenges and prospects
(BMJ Publishing Group Ltd on behalf of the British Society of Gastroenterology, 2024-01) Rehan M; Al-Bahadly I; Thomas DG; Young W; Cheng LK; Avci E
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 expanded into various domains beyond imaging, including the measurement of gut physiological parameters such as temperature, pH, pressure and gas sensing, and the development of sampling devices for better insight into gut health. In this review, the status of smart capsules for sensing gut parameters is presented to provide a broad picture of these state-of-the-art devices while focusing on the technical and clinical challenges the devices need to overcome to realise their value in clinical settings. Smart capsules are developed to perform sensing operations throughout the length of the gut to better understand the body's response under various conditions. Furthermore, the prospects of such sensing devices are discussed that might help readers, especially health practitioners, to adapt to this inevitable transformation in healthcare. As a compliment to gut sensing smart capsules, significant amount of effort has been put into the development of robotic capsules to collect tissue biopsy and gut microbiota samples to perform in-depth analysis after capsule retrieval which will be a game changer for gut health diagnosis, and this advancement is also covered in this review. The expansion of smart capsules to robotic capsules for gut microbiota collection has opened new avenues for research with a great promise to revolutionise human health diagnosis, monitoring and intervention.
The effect of dietary olive polyphenols on markers of inflammation and bodyweight in senior domestic cats
(Wageningen Academic Publishers, 2024-04) Thomas DG; Dyer P; Andrews CJ
The high rates of obesity and degenerative joint disease in companion animals has resulted in a demand for dietary supple ments that support joint health and reduce inflammation. Polyphenols have received considerable attention in this space, although literature in companion animals is lacking or conflicting. This study determined whether a diet supplemented with olive polyphenol extract had the potential to reduce inflammation and/or bodyweight. Eight senior domestic cats aged 11.01 ± 0.74 years (mean ± standard error of the mean) and weighing 3.6 ± 0.3 kg (mean ± SEM) were used for this study. The cats were fed, ad libitum with a complete (AAFCO) canned diet supplemented with 0.1% olive polyphenol extract for 56 days. Cats were weighed weekly and blood samples taken on day 0 (baseline), 28, and 56 of the study. Biochemistry, haematology, and cytokine (19 cytokines or chemokines) panels were run for each blood sample. While there was an initial aversion to the supplemented diet, intakes of the cats increased, and they consumed enough to meet or exceed their daily maintenance energy requirements by day 10 of the trial. On average, the cats lost approximately 8% of their starting weight over the trial, which was interesting given that feed intake exceeding maintenance energy requirements for most of the study. Whether the decrease in bodyweight was due to seasonal changes, the supplemented diet, or a combination of the two warrants further investigation. There were little to no changes to any of the blood parameters, which was surprising given that previous studies have reported reductions in pro-inflammatory cytokines following polyphenol supplementation. Perhaps a higher concentration of olive polyphenols is required to elicit the anti-inflammatory response observed in other species. A study evaluating the dose-dependent effects of dietary polyphenols on inflammatory and oxidative markers in cats would be valuable in this context.
The Use of Triaxial Accelerometers and Machine Learning Algorithms for Behavioural Identification in Domestic Cats (Felis catus): A Validation Study
(MDPI (Basel, Switzerland), 2023-08-14) Smit M; Ikurior SJ; Corner-Thomas RA; Andrews CJ; Draganova I; Thomas DG; Vanwanseele B
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 collected simultaneously. Identifier variables (n = 32) were calculated from the accelerometer data and summarized into 1 s epochs. Twenty-four behaviours were annotated from the video recordings and aligned with the summarised accelerometer data. Models were created using random forest (RF) and supervised self-organizing map (SOM) machine learning techniques for each mounting location. Multiple modelling rounds were run to select and merge behaviours based on performance values. All models were then tested on a validation accelerometer dataset from the same twelve cats to identify behaviours. The frequency of behaviours was calculated and compared using Dirichlet regression. Despite the SOM models having higher Kappa (>95%) and overall accuracy (>95%) compared with the RF models (64-76% and 70-86%, respectively), the RF models predicted behaviours more consistently between mounting locations. These results indicate that triaxial accelerometers can identify cat specific behaviours.
Towards Gut Microbiota Sampling Using an Untethered Sampling Device
(IEEE, 2021-09-09) Rehan M; Al-Bahadly I; Thomas DG; Avci E
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 acquiring samples of gut microbiota without contamination. In this work, an untethered robotic capsule prototype is developed that can actively collect the microbiota from the mucosa layer of the small intestine for the first time with the potential to avoid the upstream and downstream contamination. An analytical model for quantifying the peristaltic forces and developing two-way shape memory alloy spring actuator is presented. For the first time, a novel two-way shape memory alloy spring actuator (5 mm x \phi ~4 mm) is used to perform the sampling inside the gut. The spring actuator can apply 675 mN force, which is sufficient to perform in vivo sampling. A specialised experimental setup that can keep the freshly dissected intestine alive for 6 hours is utilised to test the robotic capsule. The robotic capsule prototype has collected an average of 200~\mu L and 112~\mu L sample from living pig duodenal and ileal tissues respectively i.e. in the presence of peristaltic forces. The robotic capsule was also tested on intestine of other species including cow and sheep and collected an average of 160~\mu L and 185~\mu L of content respectively from the living post-mortem tissues. The collected sample size for all the species is feasible to analyse the microbiota through next generation sequencing techniques. The experimental setup is a reliable proxy to in-vivo behaviour and the robotic capsule experimental result is promising in terms of in situ collection of microbiota.
Using meta-analysis to understand the impacts of dietary protein and fat content on the composition of fecal microbiota of domestic dogs (Canis lupus familiaris): A pilot study
(John Wiley and Sons Ltd, 2024-04) Phimister FD; Anderson RC; Thomas DG; Farquhar MJ; Maclean P; Jauregui R; Young W; Butowski CF; Bermingham EN
The interplay between diet and fecal microbiota composition is garnering increased interest across various host species, including domestic dogs. While the influence of dietary macronutrients and their associated microbial communities have been extensively reviewed, these reviews are descriptive and do not account for differences in microbial community analysis, nor do they standardize macronutrient content across studies. To address this, a meta-analysis was performed to assess the impact of dietary crude protein ("protein") and dietary crude fat ("fat") on the fecal microbiota composition in healthy dogs. Sixteen publications met the eligibility criteria for the meta-analysis, yielding a final data set of 314 dogs. Diets were classed as low, moderate, high, or supra in terms of protein or fat content. Sequence data from each publication were retrieved from public databases and reanalyzed using consistent bioinformatic pipelines. Analysis of community diversity indices and unsupervised clustering of the data with principal coordinate analysis revealed a small effect size and complete overlap between protein and fat levels at the overall community level. Supervised clustering through random forest analysis and partial least squares-discriminant analysis indicated alterations in the fecal microbiota composition at a more individual taxonomic level, corresponding to the levels of protein or fat. The Prevotellaceae Ga6A1 group and Enterococcus were associated with increasing levels of protein, while Allobaculum and Clostridium sensu stricto 13 were associated with increasing levels of fat. Interestingly, the random forest analyses revealed that Sharpea, despite its low relative abundance in the dog's fecal microbiome, was primarily responsible for the separation of the microbiome for both protein and fat. Future research should focus on validating and understanding the functional roles of these relatively low-abundant genera.

Browsing by Author "Thomas DG"

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