Neutered Cats Research Articles

MANEJO NUTRICIONAL E CONSCIENTIZAÇÃO NA PREVENÇÃO DA OBESIDADE EM GATOS CASTRADOS

Feline obesity is one of the most prevalent health issues in cats, especially following neutering, a method used for population control. Neutering is an essential measure for public health and animal welfare, which is also associated with increased food intake in cats. This procedure leads to a hormonal decrease, resulting in a reduced energy requirement for the animal. This combination often leads to weight gain if nutritional control is not implemented. With this in mind, the aim of this study is to assess the knowledge of cat owners, through a questionnaire, about nutritional management for neutered cats, emphasizing their specific needs, challenges following neutering, and dietary strategies to ensure their health and quality of life. A total of 54 responses were included, revealing that no owner follows the manufacturer’s feeding recommendations. Most owners understand the importance of nutrition but practice improper feeding, including the provision of treats. However, all respondents indicated a willingness to improve the animals' nutritional management with appropriate guidance. To address these issues, an informational guide was developed to provide advice on appropriate feeding and care for cats post-neutering. This guide includes information on specific nutritional needs, the importance of dietary control, suggestions for physical activities, and general care to promote feline well-being. The initiative aims to support owners in implementing more informed and effective practices, helping to prevent issues such as obesity and promoting a better quality of life for their pets. Continuous education for owners is essential to ensure that neutered cats receive adequate care, thereby contributing to their health and happiness.

Effect of buprenorphine delivered by target-controlled infusion on the minimum alveolar concentration of isoflurane in cats

ObjectiveTo characterize the effect of buprenorphine on the minimum alveolar concentration of isoflurane (MACiso) in cats. Study designRandomized, crossover experimental study. AnimalsA group of six healthy 2 to 8 years old male neutered cats, body mass 5.0 ± 0.3 kg. MethodsThe MACiso had been determined in each cat in a previous study. Cats were anesthetized with isoflurane in oxygen. Catheters were placed in a medial saphenous vein for drug and fluid administration and in a jugular vein for blood sampling. Buprenorphine was given intravenously using a target-controlled infusion system to reach and maintain plasma concentrations of 0.5, 1, 2, 4, 8, 16, 32 and 64 ng mL-1 and MACiso was determined in duplicate at each concentration using the tail clamp technique. Four target plasma buprenorphine concentrations were administered on each study day, with at least 2 weeks between experiments. Blood was sampled after the second MAC determination at each target for determination of plasma buprenorphine concentration. ResultsA significant effect of buprenorphine on MAC was found; however, pairwise comparisons to MACiso without buprenorphine did not reach statistical significance. Maximum reduction in MACiso in individual cats ranged from 2 to 34% at plasma buprenorphine concentrations ranging from 0.25 to 8.15 ng mL-1. Conclusions and clinical relevanceAlthough buprenorphine significantly affected MACiso in cats, the magnitude of the effect and the plasma concentration at which the largest effect occurred was highly variable among cats, limiting the clinical usefulness of buprenorphine as an agent to reduce MAC in cats.

Pathology-Based Animal Cancer Registry of Abruzzo and Molise Regions (Central Italy): A Ten-Year Retrospective Study (2014–2023)

Pets have a crucial role in cancer research. Specifically, dogs and cats share the same environment as their owners and thus may serve as sentinels of naturally occurring tumors that are linked to the exposure to environmental hazards. Quantitative comparison of tumor types may reveal unusual cancer frequencies, providing directions for research and generation of hypotheses of cancer causation in a specific area and identification of risk factors. The aim of this study was to describe the data collected by the pathology-based animal cancer registry, managed by Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise (IZSAM), during 10 years of activity (2014–2023) and to assess its potential epidemiological relevance. Frequencies of tumor topography and morphology in dogs and cats were described, analyzed and compared. Proportional morbidity ratios (PMRs) were calculated, taking into consideration some potential risk factors such as species, breed, sex, diet and living environment. The database comprises 5311 tumors (n = 4719 in dogs and n = 592 in cats), with a higher prevalence in females (67.3% in dogs and 61.2% in cats). The mean age at the first diagnosis of tumors was similar between sexes and slightly lower in dogs compared to cats. PMRs highlighted certain risk and “protective” factors for the development of tumors in specific topography. The risk of developing tumors of the blood and hematopoietic system (PMR = 0.44; 95% CI: 0.21–0.94), skin and subcutaneous tissues (PMR = 0.70; 95% CI: 0.61–0.80), oral cavity and pharynx (PMR = 0.60; 95% CI: 0.24–0.89), urinary organs (PMR = 0.33; 95% CI: 0.11–0.99) and bones, joints and cartilage (PMR = 0.72; 95% CI: 0.22–0.98) was lower in non-neutered male dogs than in neutered male dogs. Non-spayed female dogs had a greater risk of developing tumors of the mammary gland (PMR = 1.75; 95% CI: 1.57–1.96), female sexual organs (PMR = 2.12; 95% CI: 1.01–4.36) and respiratory system (PMR = 2.25; 95% CI: 1.55–6.74) but less risk for cutaneous and subcutaneous tissue tumors (PMR = 0.44; 95% CI: 0.38–0.51) and blood/hematopoietic system tumors (PMR = 0.47; 95% CI: 0.26–0.85) compared to spayed female dogs. Compared with mixed breed, purebred dogs had a significantly greater risk of developing mammary gland tumors (PMR = 1.36; 95% CI: 1.20–1.54) and lower risk for respiratory (PMR = 0.15; 95% CI: 0.07–0.32), gastrointestinal (PMR = 0.63; 95% CI: 0.34–0.94) and oral (PMR = 0.59; 95% CI: 0.36–0.96) neoplasia. Non-neutered male cats had a lower risk of developing skin and subcutaneous tumors (PMR = 0.68; 95% CI: 0.50–0.92) compared with neutered cats. The risk of developing skin and subcutaneous tissues tumors was higher for dogs and cats that lived mostly outdoor (PMR dogs = 1.21; 95% CI: 1.10–1.33; PMR cats = 1.18; 95% CI: 1.08–1.47), while dogs that live mainly indoor had a greater risk to develop mammary gland tumors (PMR = 0.78; 95% CI: 0.68–0.89). Results described herein highlight the fundamental role of animal cancer registration initiatives. These efforts would contribute to the possibility of conducting multicentric collaborative studies to deepen the knowledge of the epidemiology of tumors in dogs and cats from a comparative perspective, thus fulfilling the One Health approach.

502 Cat and mouse: The effect of consuming four different diet formants (intact mice, raw, canned wet and kibble) on energy expended to consume a meal and immediately post-prandial in domestic cats

Abstract Cats are obligate carnivores; however, we feed them a variety of different diet formats without a clear understanding of feeding behavior and metabolism among diet formats. Whole-prey or raw diets may mimic a more natural diet and require more energy to consume. However, there is currently a dearth of literature examining feline energy expenditure (EE) during the consumption of and immediate post-prandial period when fed different diet formats. The present study aimed to investigate differences in the energetics of adult cats consuming four different diet formats in isocaloric offerings: raw intact mice, commercial raw, canned wet, and kibble diets. Adult neutered male cats [n = 12; body weight (BW) = 4.82 ± 0.164 kg) were used in a 4 x 4 replicated Latin square design and adapted to consuming each diet format before the initiation of the study. Following a 2-d adaptation period, cats were fed 25% of their daily caloric requirement (50.77 ± 1.549 kcal) in indirect calorimetry chambers in which VO2 and VCO2 exchange were measured. Energy expenditure (kcal/BW0.67 kg) was calculated for the consumption period, 15 min immediately post-prandial and 2 h post-prandial. Respiratory gases were measured for one fasted reading, followed by the first feeding. During each feeding, measurements were taken during the consumption period and 15 min post-prandial. For the following 2 h, respiratory gases were measured every 25 min for an additional 4 measures of respiratory gases. All data were analyzed using a generalized linear mixed model considering the effects of treatment, time and their interaction as fixed, and the effects of cat and period as random. A spatial power covariance structure was used to model repeated measures. Significance was considered at P < 0.05 and Tukey’s post-hoc test was performed to separate means. Energy expenditure during consumption and 15 min post-prandial was similar among treatments, and EE for 15 min post-prandial was greater than EE during consumption (P < 0.001). During the 2 h post-prandial, EE for the mice diet was greater than the kibble and canned wet diets (P < 0.001), while EE for the raw diet was only greater than the kibble diet (P < 0.001). Energy expenditure was similar between the kibble and canned wet diets (P = 0.919) and between the mice and raw diets (P = 0.598). Among all treatments and time periods, the mouse diet had the greatest mean EE. An increase in EE during the feeding period and post-prandial could benefit sedentary indoor cats who may be in positive energy balance. Feeding cats a naturalistic diet, such as intact mice or a raw diet, may increase activity levels and EE, but the longer-term effects of these feeding formats on energy balance need to be explored.

308 Isoenergetic reduction of dietary macronutrients reveals distinct fecal metabolomic signatures in lean and obese cats fed at maintenance

Abstract Obesity has become a concerning problem in cats. Increasing evidence demonstrates the utility of metabolomics in identifying disease biomarkers and assessing the effects of nutritional interventions, although limited information exists regarding alterations in fecal metabolites in lean and obese domestic cats in response to different macronutrient content. In the current study, three extruded diets were formulated based on adult maintenance using an isoenergentic approach. These diets were created by adjusting the levels of identical ingredients to achieve a low-protein [LP; protein 28% metabolizable energy (ME), fat 40%ME, NFE 32% ME), a low-fat (LF; protein 42% ME, fat 30% ME, NFE 30% ME), and a low-carbohydrate (LC; protein 36% ME, fat 41% ME, NFE 23% ME] diet. Healthy neutered male adult cats [n = 18; body condition scores (BCS) 4 or 5 (lean, n = 9) and 8 or 9 (obese, n = 9)] were fed each diet for a period of 4 wk in a 3 x 3 Latin square design. Fecal samples from each cat were collected between d 22 and 28 of each treatment period. A total of 67 fecal metabolites in six groups (35 amino acids, 11 fatty acids, 10 sugars and sugar metabolites, 5 alcohols, 3 nitrogenous bases, and 3 others) were analyzed using 1H NMR spectroscopy. To evaluate the impact of body condition, diet and their interaction on each metabolite, proc GLIMMIX covariance structure was selected by the smallest Akaike information criterion value in SAS. The Shapiro-Wilk test was used to check normality and lognormal or beta distribution were applied when appropriate. Bonferroni correction post-hoc test was followed to correct Type I error. Statistical significance was considered at P < 0.05. In lean cats, significantly greater concentrations of fecal proteinogenic and branched-chain amino acids, such as methionine, valine, and L-lysine, as well as pyruvic acid and sugars (P < 0.05) were observed. This suggests that these metabolites may either be more actively fermented by bacteria or not utilized as extensively as in obese cats, potentially contributing to a reduction in obesity status. Regardless of body condition, there is a possibility of an enhanced activity in the tryptophan degradation pathway, leading to the greatest concentrations of fecal tryptophan (P = 0.04) in the LF diet, while the greatest fecal D-galactose (P = 0.04) in the LP diet was likely due to the greater dietary carbohydrate content. These observed results suggested that fecal metabolites were influenced by both body condition and diet; however, body condition had a more substantial impact on metabolite changes in cats, whereas no body condition and diet interaction were noted. Overall, the study indicated distinct fecal metabolic signatures in lean and obese cats subjected to different macronutrient diets and further research is warranted to validate the observed findings. Funding was provided by Champion Petfoods, Natural Sciences and Engineering Council of Canada and Mitacs Accelerate.

291 Isoenergetic reduction of dietary macronutrients changes body composition and physical activity in cats, regardless of body condition, when fed to maintenance

Abstract Commercial extruded cat foods deviate noticeably from the natural diet of wild cats and contain greater carbohydrate and less protein. This alteration in macronutrient distribution is postulated as a potential factor in feline obesity, yet the precise role of carbohydrates in either predisposing to, or treating, obesity in cats remains inconclusive. This study explored the effects of diets differing in protein, fat, and carbohydrates (NFE) on physical activity and body composition when fed to adult male cats to maintain body weight (BW). Three extruded diets were formulated for adult maintenance according to AAFCO in an isoenergetic approach using the same ingredients in varying proportions: low-protein (LP; protein 28% of metabolizable energy [ME], fat 40% ME, NFE 32% ME), low-fat (LF; protein 42% ME, fat 30% ME, NFE 30% ME), or low-carbohydrate (LC; protein 36% ME, fat 41%ME, NFE 23% ME). Lean (n = 9) and obese (n = 9) adult male neutered cats were fed each diet for 4-wk in a 3 x 3 Latin square design. Physical activity was measured via actigraphy on d 15 to 21 of each period. On d 23 total tissue mass (TTM), body fat mass (BFM), lean soft tissue mass (LSTM), and bone mineral content (BMC) were assessed by dual energy x-ray absorptiometry. Daily food intake and weekly BW were recorded. Data were statistically analyzed in SAS Studio via the GLIMMIX procedure with diet and body condition (bc) as fixed effects and cat as subject. A Tukey post-hoc analysis was performed to assess multiple comparisons when significant (P < 0.05). Body weight (Pbc < 0.0001), TTM (Pbc < 0.0001), BFM (Pbc < 0.0001), LSTM (Pbc < 0.0001), and BMC (Pbc = 0.004) were greater in obese compared with lean cats. Regardless of body condition, LSTM was greater in cats consuming the LF diet (P = 0.010). Daily physical activity was similar between lean and obese cats; however, activity as a ratio of light:dark activity was greater for lean cats compared with obese (Pbc = 0.027). Additionally, cats were more active during dark hours when fed LC and LF (Pdiet = 0.016), though no difference was observed for activity during light hours (P = 0.452). These findings support previous observations regarding body composition disparities between lean and obese cats. Contrary to previous reports, no discernible distinctions in voluntary physical activity were noted between lean and obese cats. In previous studies, both high-carbohydrate and high-fat diets reduced voluntary physical activity when fed to maintain BW which was attributed to a potential alteration in mood and energy levels seen in other species. An increase in physical activity in cats consuming the LF diet could suggest a similar pattern. Future research should explore the metabolic implications of varied macronutrient distributions to expand upon the physiological insights presented herein. Funding for this study was provided by Champion Petfoods, Mitacs Accelerate, and the Natural Sciences and Engineering Council of Canada.

First Molecular Evidence of Leishmania Infantum in Domestic Cats and Associated Risk Factors from the Black Sea Region of Türkiye.

The objectives of the present study are to determine the molecular prevalence of Leishmania spp. in the owned domestic cats in the Black Sea Region of Türkiye and analyze the associated risk factors in FeL. Conjunctival swabs (CS), blood, demographic, and clinical data were collected from 150 owned cats brought to the Veterinary Teaching Hospital during 2020-2022. Leishmania kinetoplast DNA (kDNA) from CS was screened by TaqMan Real-Time PCR (qPCR) with the genus-specific primers and a probe. All qPCR positive products were also amplified and sequenced to identify Leishmania species by ITS1 primers. Molecular prevalence of L. infantum found as 12.6% (19/150) in the observed cats in the Black Sea Region of Türkiye. There was a significant difference (p < 0.05) between neutered and intact cats with regarding to L. infantum positivity. Intact cats found to be 0.368 times more prone to be L. infantum-positive (L+). Dermatological lesions were found the most common (26.3%) problems in the L + cats. The median leucocyte count was the only parameter that was found statistically (p < 0.05) lower in the L + group (6.60) than the negative group (L-) (8.96), when comparing the WBC, NEU/LYM, MONO/LYM, EOS/LYM and PLT/LYM values. This study presented the molecular occurrence of FeL in the Black Sea Region of Türkiye for the first time indicating that the carrier status of the cats makes them alternative reservoirs for possible zoonotic transmission of L. infantum in this zone.

Correlation, agreement and concordance of cardiac output estimated by transthoracic ultrasound and transesophageal Doppler with pulmonary artery thermodilution in anesthetized cats

ObjectiveTo characterize the correlation, agreement and concordance of cardiac output (CO) measured with transthoracic ultrasound and the correlation and concordance of aortic blood flow (ABF) minute distance (MD) measured by transesophageal Doppler with CO measured by pulmonary artery thermodilution (PATD) in cats. Study designExperimental study. AnimalsA group of six healthy male neutered cats, aged 2–8 years and weighing 5.3 ± 0.3 kg. MethodsCats were anesthetized with isoflurane in oxygen. CO was measured by PATD (COPATD) and transthoracic echocardiography (COECHO). ABF MD was measured using an esophageal Doppler flow probe aligned with descending ABF. All measurements were made under three conditions: dexmedetomidine (20 μg kg–1) intravenously; atipamezole (200 μg kg–1) intramuscularly and atropine (20 μg kg–1) intravenously as needed to achieve a minimum heart rate of 140 beats minute–1; and dopamine (20 μg kg–1 minute–1) intravenously in that order. Correlation between COPATD and COECHO, and COPATD and Doppler MD was evaluated using repeated measures correlation. Agreement between COPATD and COECHO was evaluated using Bland–Altman method. Differences between consecutive pairs of CO measurements were calculated for concordance analysis. ResultsCorrelation between COPATD and COECHO and between COPATD and MD was significant (p < 0.001), with correlation coefficients greater than 0.92. A bias of > 27% and upper limits of agreement of 66% were found between COPATD and COECHO. Concordance rate with COPATD was 76–80% for COECHO and 72% for MD. Conclusions and clinical relevanceEchocardiographic methods for the measurement of CO showed poor agreement and concordance with PATD. MD showed poor concordance with PATD. As such, these methods cannot be used as an alternative to PATD nor can they appropriately track changes in CO in anesthetized cats.

Evaluation of cryptorchidism in cats and dogs

Objective: Cryptorchidism, the failure of one or both testes to descend into the scrotum, is a common congenital condition in male dogs and cats. This study aimed to assess the incidence and characteristics of cryptorchidism in neutered dogs and cats. Materials and Methods: A retrospective analysis was conducted on 1622 animals (348 dogs and 1274 cats) brought for neutering between 2015 and 2023. Cryptorchid was diagnosed by clinical examination and its location was determined by ultrasound examination. Animals diagnosed with cryptorchid were castrated. Breed, age weight data and location of the retained testicle of all patients were recorded. Results: Dogs exhibited a higher prevalence (8.91%) compared to cats (3.30%). The affected testes were predominantly subcutaneous in both species (61.29% in dogs, 73.81% in cats). Unilateral cryptorchidism was more common, with equal distribution between the right and left sides in dogs and a higher incidence on the left in cats. Purebred animals, particularly small-sized breeds, showed a higher susceptibility to cryptorchidism. Conclusion: Our study provides valuable insights into the prevalence, localization, and characteristics of cryptorchidism in dogs and cats, emphasizing the importance of detection and intervention to safeguard the health of affected animals. The findings highlight the higher susceptibility of purebred dogs and cats.

Efeitos anátomo-fisiológicos da castração pré-púbere em felinos (Felis catus) – revisão de literatura

Pre-pubertal castration in felines is a highly effective strategy for managing stray animal populations, thereby benefiting both public health and animal welfare. It helps prevent unwanted pregnancies, minimizes human-stray animal conflicts, and curtails the spread of diseases transmitted through mating. However, this practice has sparked debates among veterinarians and pet owners due to potential adverse effects. Surgical and anesthetic complications, including hypothermia and hypoglycemia, are concerns during pediatric procedures. There is also a possibility of altered development of secondary sexual characteristics, although these changes typically do not impact the animals' overall well-being. Metabolically, neutered cats tend to gain weight, raising the risk of obesity and diabetes mellitus. Skeletal concerns involve delayed bone closure, yet bone density remains largely unaffected. Lower urinary tract issues, like incontinence or obstruction, may also arise, albeit through complex mechanisms. Despite these concerns, the benefits of pre-pubertal castration in managing overpopulation and reproductive diseases outweigh the risks. With vigilant veterinary care and post-operative management, adverse effects can be mitigated, underscoring the importance of this practice in controlling stray cat populations.

Minimum methionine requirement in adult cats as determined by indicator amino acid oxidation.

There is a lack of empirical data on the dietary Met requirement, in the presence of Cys or cystine, in adult cats. Thus, the aim of this study was to determine the Met requirement, in the presence of excess Cys, in adult cats at maintenance using the indicator amino acid oxidation (IAAO) technique. Six adult neutered male cats were initially selected and started the study. Cats were adapted to the basal diet sufficient in Met (0.24% dry matter, DM) for 14 d prior to being randomly allocated to one of eight dietary levels of Met (0.10%, 0.13%, 0.17%, 0.22%, 0.27%, 0.33%, 0.38%, and 0.43% DM). Different dietary Met concentrations were achieved by supplementing the basal diet with Met solutions. Alanine was additionally included in the solutions to produce isonitrogenous and isoenergetic diets. Cats underwent a 2-d adaptation period to each experimental diet prior to each IAAO study day. On IAAO study days, 13 meals were offered corresponding to 75% of each cat's daily food allowance. The remaining 25% of their daily food intake was offered after each IAAO study. A bolus dose of NaH13CO3 (0.44mg kg-1) and l-[1-13C]-phenylalanine (13C-Phe; 4.8mg kg-1) were provided in fifth and sixth meals, respectively, followed by a constant dose of 13C-Phe (1.04mg kg-1) in the next meals. Breath samples were collected and total production of 13CO2 was measured every 25min through respiration calorimetry chambers. Steady state of 13CO2 achieved over at least three breath collections was used to calculate oxidation of 13C-Phe (F13CO2). Competing models were applied using the NLMIXED procedure in SAS to determine the effects of dietary Met on 13CO2. Two cats were removed from the study as they did not eat all meals, which is required to achieve isotopic steady. A breakpoint for the mean Met requirement, with excess of Cys, was identified at 0.24% DM (22.63mg kg-1) with an upper 95% confidence limit of 0.40% DM (37.71 mg·kg-1), on an energy density of 4,164 kcal of metabolizable energy/kg DM calculated using the modified Atwater factors. The estimated Met requirement, in the presence of excess of Cys, is higher than the current recommendations proposed by the National Research Council's Nutrient Requirement of Dogs and Cats, the Association of American Feed Control Officials, and the European Pet Food Industry Federation.

Alfaxalone increases measured progesterone concentration in neutered male cats when determined by immunoreactivity.

Alfaxalone is a commonly used anesthetic agent in small animals. In cats, alfaxalone can be administered as an IM agent to achieve clinically useful sedation or anesthesia, negating the need for IV injection in difficult patients. The molecular structure of alfaxalone is similar to the hormone progesterone (P4). It is hypothesized that alfaxalone would cross-react with the assay measuring progesterone causing a false elevation. 8 healthy neutered male, domestic shorthair cats that were privately owned were enrolled in the study. Male neutered cats were administered 3 mg/kg of alfaxalone IM. Blood samples were collected at set time points (baseline, 30 minutes, 60 minutes, 3 hours, 6 hours, and 10 hours after administration), and serum concentrations of progesterone immunoreactivity (IR) were determined using the Siemens Immulite 1000 automated immunoassay system. Statistical analysis was performed with repeated measures ANOVA and a Tukey-Cramer multiple comparisons test. A P value of < .05 was used for significance. Serum progesterone IR was significantly elevated at 30 minutes, 1 hour, and 3 hours (P < .05) when compared to baseline progesterone immunoreactivity. Progesterone immunoreactivity had returned to baseline by 6 hours. This study suggests that alfaxalone administered IM in cats may interfere with immunoassay measurement of serum progesterone for up to 6 hours. Caution should be used when interpreting serum progesterone immunoreactivity results in cats within 4 hours of alfaxalone.

195 Restricted Feeding and Weight Loss Change Fecal Metabolite Concentrations and Microbiota Populations of Overweight Cats

Abstract Feline obesity negatively influences many metabolic processes, health outcomes, and the individual well-being of cats, but little research evaluates the modification in gastrointestinal microbiota in an overweight state. The use of specially formulated diets and restricted feeding, resulting in subsequent body weight (BW) loss, may be used to improve health and modify gastrointestinal microbiota of overweight cats. This study aimed to identify and determine the effects of restricted feeding and BW loss on fecal metabolite concentrations and microbiota populations of overweight cats. All procedures were approved by the University of Illinois IACUC before experimentation. Twenty-two overweight adult spayed female and neutered male cats [BW = 5.70 ± 1.0 kg; BCS = 7.68±0.6; age = 4 ± 0.4 yr] were used in a 24-wk BW loss study. A control diet (OR) was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (wk 0), cats were allotted to OR or a BW loss diet (FT) and fed to lose ~1.0% BW/wk. Fecal samples were collected at baseline (wk 0), and weeks 4, 8, 12, 16, 20, and 24 for microbiota and metabolite analyses. Fecal microbiota data were analyzed and evaluated using QIIME2 and Mixed Models procedure of SAS, with P &amp;lt; 0.05 considered significant. Change from baseline fecal acetate, propionate, butyrate, total short-chain fatty acid, isobutyrate, valerate, phenol, indole, and total phenol and indole concentrations were reduced (P &amp;lt; 0.05) with restricted feeding and BW loss. Change from baseline fecal scores and valerate concentrations were also affected by diet, with greater (P &amp;lt; 0.05) reductions occurring in cats fed OR than those fed FT. Change from baseline fecal pH was also greater (P = 0.05) in cats fed OR than those fed FT. Fecal bacterial alpha diversity was not affected by diet or restricted feeding and BW loss. However, fecal bacterial beta diversity, assessed by weighted and unweighted UniFrac distances and presented as principal coordinate plots, showed separation between dietary groups, with some significant clustering as a result of restricted feeding and weight loss. The relative abundances of a single fecal bacterial phylum and 5 fecal bacterial genera were impacted by restricted feeding and weight loss. Diet had a greater effect, with 3 fecal bacterial phyla and 19 fecal bacterial genera being different (P &amp;lt; 0.05) between dietary treatment groups. Our data demonstrate that restricted feeding of specially formulated diets, and subsequent BW loss, modifies the fecal metabolite profiles and microbiota populations of overweight cats. The mechanisms by which these changes may affect feline gastrointestinal health and metabolism requires further study.

190 The Nutrigenomic Effects of Dietary Choline and L-Carnitine on the Muscle and Liver of Lean and Overweight Cats

Abstract The objective of this study was to investigate the effects of dietary choline and L-carnitine on the lipotropic gene expression in the muscle and liver of overweight and lean cats, when fed for body weight (BW)maintenance. Overweight [n = 6, body fat percent (BF%): 33.2 ± 1.38] and lean (n = 6, BF%:18.4 ± 0.93), 1-2 year old, male, neutered cats received choline (378 mg/kg BW0.67), L-carnitine (200 mg/kg BW) and no supplementation (control) in a 3x3 Latin square design for 6 weeks, with a 2-week washout between treatments periods. Each treatment was offered with a commercial extruded diet; diet amount was provided to maintain current BW. Cats were anesthetized and quadriceps vastus lateralis (30-50 mg) and liver (30-50 mg) biopsies were harvested after each treatment period using an open muscle or laparoscopic biopsy technique respectively. Tissue RNA was isolated with TRIzol and sequenced using directional PolyA RNA-seq. The expressed genes were aligned using the reference genome, Felis_catus_9.0, Ensembl v.107. Differential gene expression was analyzed for 29,928 genes with SEQUIN, using edgeR and TMM normalization. Pathway analysis was performed using EnrichR databases, BioPlanet 2019 and KEGG 2021. Using a two-group comparison, global analysis revealed 92 and 759 differentially expressed genes in the liver and muscle, respectively of overweight cats compared with lean (P &amp;lt; 0.05). Affected pathways included fat digestion and absorption, including peroxisome proliferator-activated receptor (PPAR) signaling in the liver, and immunity related pathways in muscle (P &amp;lt; 0.05). Upon further analysis using a two-group comparison between overweight and lean cats for each treatment, 11 and 692 significant genes were found in choline treated liver samples and L-carnitine treated muscle samples, respectively (P &amp;lt; 0.05). Similar to the global analysis, genes related to fat metabolism, including PPAR signaling, were significant in the choline treated liver samples, and immunity related genes were significant in the L-carnitine treated muscle samples (P &amp;lt; 0.05). Based on preliminary data, supplemental dietary choline may be beneficial for overweight cats as it may increase fat metabolism in the liver, mitigating risks associated with feline hepatic lipidosis (FHL). Supplemental dietary L-carnitine may also be beneficial due to its effects on immunity related pathways, including pathogen defense. To investigate the full effects of choline and L-carnitine on gene expression, further studies are warranted including older, chronically obese cats, as well as confirmed cases of FHL. Acknowledgements: Natural Sciences and Engineering Council of Canada, Elmira Pet Products and Balchem Corp.

Dietary choline, but not L-carnitine, increases circulating lipid and lipoprotein concentrations, without affecting body composition, energy expenditure or respiratory quotient in lean and obese male cats during weight maintenance.

Due to the involvement in one-carbon metabolism and lipid mobilization, choline and L-carnitine supplementation have been recommended to minimize hepatic lipid accumulation and support fat oxidation, respectively. This study investigated the lipotropic benefits of choline or L-carnitine supplementation in lean and obese cats maintaining body weight (BW). Lean [n = 9; body condition score (BCS): 4-5/9] and obese (n = 9; BCS: 8-9/9) adult male neutered colony cats were used in a replicated 3 x 3 complete Latin square design. Treatments included choline (378 mg/kg BW0.67), L-carnitine (200 mg/kg BW) and control (no supplement). Treatments were supplemented to the food for 6 weeks each, with a 2-week washout between treatments. Cats were fed once daily to maintenance energy requirements, and BW and BCS were assessed weekly. Fasted blood collection, indirect calorimetry, and dual-energy X-ray absorptiometry occurred at the end of each treatment period. Serum was analyzed for cholesterol (CHOL), high-density lipoprotein CHOL (HDL-C), triglycerides (TAG), non-esterified fatty acids (NEFA), glucose, creatinine (CREAT), urea, alkaline phosphatase (ALP) and alanine aminotransferase (ALT). Very low-density lipoprotein CHOL (VLDL) and low-density lipoprotein CHOL (LDL-C) were calculated. Data were analyzed using proc GLIMMIX, with group and period as random effects, and treatment, body condition, and their interaction as fixed effects, followed by a Tukey's post-hoc test when significance occurred. Cats supplemented choline had lower food intake (P = 0.025). Treatment did not change BW, BCS and body composition (P > 0.05). Obese cats had greater ALP, TAG, and VLDL, and lower HDL-C compared to lean cats (P < 0.05). Choline resulted in greater CHOL, HDL-C, LDL-C and ALT (P < 0.05). L-carnitine resulted in lower CREAT (P = 0.010). Following the post-hoc test, differences between treatment means were not present for ALP (P = 0.042). No differences were found for glucose, urea or NEFA (P > 0.05). Obese cats had a lower fed respiratory quotient (RQ), regardless of treatment (P = 0.045). Treatment did not affect fed or fasted RQ and energy expenditure (P > 0.05). Choline appeared to increase circulating lipid and lipoprotein concentrations regardless of body condition, likely through enhanced lipid mobilization and hepatic elimination. Neither dietary choline or L-carnitine altered body composition or energy metabolism in the lean or obese cats, as compared to control.

Clinical Characterisation of Caudal Traumatic Malocclusions and Treatment Outcomes in Cats (2018-2022).

Caudal malocclusions in cats may result in a variety of traumatic lesions affecting the soft tissues of the ipsilateral mandible such as fovea, gingival cleft, and proliferative lesions. Fifty-one cats diagnosed with a traumatic caudal malocclusion were compared with a control hospital population and evaluated for prevalence with respect to breed and sex. Twenty-two cats that were treated had radiographic, clinical findings, and the outcome of treatment (extraction or odontoplasty) recorded. Maine Coon, Persian, and male neutered cats were overrepresented while Domestic Shorthairs were underrepresented within the study population. Radiographically, 50% of the fovea lesions had an area of decreased bone density in the region of the lesion and none of these had evidence of periodontal disease. All gingival cleft lesions had radiographic changes consistent with periodontal disease. 15.4% of proliferative lesions presented with radiographic changes, with only half of those presenting with both radiographic and clinical evidence of periodontal disease. Eleven cats were treated by odontoplasty and eleven by extraction. One cat treated by odontoplasty developed new lesions caudally, and another had persistence of the initial lesions. Two cats in the extraction group developed new lesions rostral to the extracted teeth. In most instances, odontoplasty or extraction resulted in successful soft tissue lesion resolution. In rare cases, additional treatment was necessary due to either persistence or development of new lesions.

Successful management of minoxidil 5% toxicosis in 2 cats from the same household.

To describe the successful management of 2 cats following ingestion of minoxidil 5%. Two 2-year-old neutered male Savannah cats were presented following suspected minoxidil 5% ingestion. Both cats developed significant myocardial injury, and clinical signs were consistent with congestive heart failure, supported by cardiac troponin I concentrations, echocardiogram, and thoracic radiographs. They required vasopressor therapy and were decontaminated with intravenous lipid emulsion therapy. Following decontamination, both cats were successfully discontinued from vasopressor therapy, and their clinical signs resolved within 24hours. The cats were successfully discharged without long-lasting cardiac compromise. Their echocardiograms and cardiac troponin concentration 7weeks after discharge were within reference intervals. This is the first detailed report of the successful management of cats following minoxidil 5% ingestion.

Pharmacokinetics of buprenorphine and its metabolite norbuprenorphine in neutered male cats anesthetized with isoflurane

ObjectiveTo characterize the pharmacokinetics of buprenorphine and norbuprenorphine in isoflurane-anesthetized cats. Study designProspective experimental study. AnimalsA group of six healthy adult male neutered cats. MethodsCats were anesthetized with isoflurane in oxygen. Catheters were placed in a jugular vein for blood sampling and in a medial saphenous vein for buprenorphine and lactated Ringer’s solution administration. Buprenorphine hydrochloride (40 μg kg–1 over 5 minutes) was administered intravenously. Blood samples were collected before buprenorphine administration and at various times up to 12 hours after administration. Plasma buprenorphine and norbuprenorphine concentrations were measured using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-concentration data using nonlinear mixed effect (population) modeling. ResultsA five-compartment model (three compartments for buprenorphine and two compartments for norbuprenorphine) best fitted the data. Typical value (% interindividual variability) for the three buprenorphine volumes of distribution, and the metabolic clearance to norbuprenorphine, the remaining metabolic clearance and the two distribution clearances were 157 (33), 759 (34) and 1432 (43) mL kg–1, and 5.3 (33), 16.4 (11), 58.7 (27) and 6.0 (not estimated) mL minute–1 kg–1, respectively. Typical values (% interindividual variability) for the two norbuprenorphine volumes of distribution, and the norbuprenorphine metabolic and distribution clearances were 1437 (30) and 8428 (not estimated) mL kg–1 and 48.4 (68) and 235.9 (not estimated) mL minute–1 kg–1, respectively. Conclusions and clinical relevanceThe pharmacokinetics of buprenorphine in isoflurane-anesthetized cats were characterized by a medium clearance.

Comparison of growth in neutered Domestic Shorthair kittens with growth in sexually-intact cats.

The first aim of these studies was to compare growth patterns of healthy kittens neutered during growth with growth standards created for sexually-intact kittens. A second aim was to clarify the impact of neutering in kittens on body composition and body shape. Study 1 was a retrospective observational study comparing median growth trajectories of healthy, client-owned domestic shorthair (DSH) kittens in optimal body condition and neutered at different ages, with previously-created growth standards from a similar, sexually-intact, population. The neuter groups contained between 3.0k and 9.3k cats. For all neuter groups in both sexes, the median growth trajectory inclined upwards after the procedure, with this being more marked in female than in male kittens. This upwards inclination was less marked for kittens neutered later during growth in both sexes, with the effect being least in kittens neutered after 28-29 weeks. Study 2 was an analysis of new body composition and zoometric data from a previously-published randomised study, comparing growth-related measures between 11 pairs of sexually-intact and neutered (at 19 weeks age) female DSH cats in a research population. Before neutering, the growth pattern in neutered kittens and sexually-intact kittens was similar, but neutered kittens were heavier by 52 weeks (mean difference in fold change vs. 10 weeks 1.34, 95-CI: 1.07-1.72), had a greater fat mass (mean difference in fold change vs. 10 weeks 1.91, 95-CI 1.09-3.21) and greater lean mass (mean difference in fold change vs. 10 weeks 1.23, 95-CI: 1.03-1.48). Abdominal girth (mean difference in fold change vs. 10 weeks 1.20, 95-CI: 1.04-1.39) and rib cage length (mean difference in fold change vs. 10 weeks 1.18, 95-CI: 1.02-1.36) were also greater, but there were no differences in other zoometric measurements. Veterinarians should consider the potential impact that neutering has on gain of adipose tissue, especially early neutering in female kittens. Bodyweight should be monitored closely during growth and especially after neutering to prevent inappropriate weight gain.

Effects of weight loss and feeding specially formulated diets on the body composition, blood metabolite profiles, voluntary physical activity, and fecal metabolites and microbiota of overweight cats.

Feline obesity is a common and preventable disease, posing a myriad of health risks and detriments. Specially formulated diets and restricted feeding may serve as an intervention strategy to promote weight loss and improve feline health. In this study, our objective was to determine the effects of restricted feeding and weight loss on body composition, voluntary physical activity, blood hormones and metabolites, and fecal microbiota of overweight cats. Twenty-two overweight adult spayed female and neutered male cats [body weight (BW) = 5.70 ± 1.0 kg; body condition score (BCS) = 7.68 ± 0.6; age = 4 ± 0.4 yr] were used in a weight loss study. A control diet (OR) was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (week 0), cats were allotted to OR or a test diet (FT) and fed to lose ~1.0% BW/wk for 24 wk. At baseline and 6, 12, 18, and 24 wk after weight loss, dual-energy x-ray absorptiometry scans were performed and blood samples were collected. Voluntary physical activity was measured at weeks 0, 8, 16, and 24. Fecal samples were collected at weeks 0, 4, 8, 12, 16, 20, and 24. Change from baseline data were analyzed statistically using the Mixed Models procedure of SAS, with P < 0.05 considered significant. Restricted feeding of both diets led to weight and fat mass loss, lower BCS, and lower blood triglyceride and leptin concentrations. Cats fed the FT diet had a greater reduction in blood triglycerides and cholesterol than cats fed the OR diet. Restricted feeding and weight loss reduced fecal short-chain fatty acid, branched-chain fatty acid, phenol, and indole concentrations. Fecal valerate concentrations were affected by diet, with cats fed the OR diet having a greater reduction than those fed the FT diet. Fecal bacterial alpha diversity was not affected, but fecal bacterial beta diversity analysis showed clustering by diet. Restricted feeding and weight loss affected relative abundances of 7 fecal bacterial genera, while dietary intervention affected change from baseline relative abundances of 2 fecal bacterial phyla and 20 fecal bacterial genera. Our data demonstrate that restricted feeding promoted controlled and safe weight and fat loss, reduced blood lipids and leptin concentrations, and shifted fecal metabolites and microbiota. Some changes were also impacted by diet, highlighting the importance of ingredient and nutrient composition in weight loss diets.