The effect of changing the moisture levels of dry extruded and wet canned diets on physical activity in cats

High starch intake favours body weight control in neutered and spayed cats living in homes fed ad libitum

Different starch-to-protein ratios were compared among neutered and spayed domiciled cats. Male and female obese and non-obese cats were fed kibble diets ad libitum for 4 months high in starch (HS (38 % crude protein (CP)): starch 32 %, protein 38 %; DM basis) or high in protein (HP (55 % CP): starch 19 %, protein 55 %) but similar in energy and fat in a crossover design. Physical activity was evaluated using an accelerometer, and body composition (BC), energy expenditure (EE) and water turnover (WT) using the doubly labelled water method. Results were compared in a 2 diet × 2 sex × 2 body condition factorial arrangement. Cats fed the HS (38 % CP) diet maintained a constant body weight, but lean mass (LM) tended to be reduced in female obese but to be increased in male non-obese (P < 0·08) and increased in female non-obese cats (P = 0·01). The HP (55 % CP) diet induced an increase in cat body weight and LM (P < 0·05) without altering BC proportion. EE tended to be higher in males (351 (se 8) kJ/kg0·67/d) than females (330 (se 8) kJ/kg0·67/d; P = 0·06), was unaffected by diet or BC, decreased as age increased (R 2 0·44; P < 0·01) and increased as physical activity increased (R 2 0·58; P < 0·01). WT was higher for the HP (55 % CP) diet (P < 0·01) and increased with EE (R 2 0·65; P < 0·01). The HS (38 % CP) diet favoured body weight control during 4 months of ad libitum feeding. Caution is necessary to balance protein in diets of female obese cats over 5 years, as they may have low energy and food intake, with LM loss.

Identifying animal behaviours from accelerometers: Improving predictive accuracy of machine learning by refining the variables selected, data frequency, and sample duration

Observing animals in the wild often poses extreme challenges, but animal-borne accelerometers are increasingly revealing unobservable behaviours. Automated machine learning streamlines behaviour identification from the substantial datasets generated during multi-animal, long-term studies; however, the accuracy of such models depends on the qualities of the training data. We examined how data processing influenced the predictive accuracy of random forest (RF) models, leveraging the easily observed domestic cat (Felis catus) as a model organism for terrestrial mammalian behaviours. Nine indoor domestic cats were equipped with collar-mounted tri-axial accelerometers, and behaviours were recorded alongside video footage. From this calibrated data, eight datasets were derived with (i) additional descriptive variables, (ii) altered frequencies of acceleration data (40 Hz vs. a mean over 1 s) and (iii) standardised durations of different behaviours. These training datasets were used to generate RF models that were validated against calibrated cat behaviours before identifying the behaviours of five free-ranging tag-equipped cats. These predictions were compared to those identified manually to validate the accuracy of the RF models for free-ranging animal behaviours. RF models accurately predicted the behaviours of indoor domestic cats (F-measure up to 0.96) with discernible improvements observed with post-data-collection processing. Additional variables, standardised durations of behaviours and higher recording frequencies improved model accuracy. However, prediction accuracy varied with different behaviours, where high-frequency models excelled in identifying fast-paced behaviours (e.g. locomotion), whereas lower-frequency models (1 Hz) more accurately identified slower, aperiodic behaviours such as grooming and feeding, particularly when examining free-ranging cat behaviours. While RF modelling offered a robust means of behaviour identification from accelerometer data, field validations were important to validate model accuracy for free-ranging individuals. Future studies may benefit from employing similar data processing methods that enhance RF behaviour identification accuracy, with extensive advantages for investigations into ecology, welfare and management of wild animals.

Wet-food diet promotes the recovery from surgery of castration and control of body weight in adult young cats

Inappropriate dietary management may lead to delayed recovery from castration surgery and significant weight gain in cats after castration. Wet canned food often exhibits more advantageous characteristics than dry food (e.g., higher palatability and digestibility, and lower energy density). This study compared the effects of canned and dry food on surgical recovery and weight management in cats after castration. Eighteen healthy cats (weighed 4.33 ± 1.04 kg and aged 18-months old) were allocated to one of the two dietary treatments (N = 9/group), dry (CON) and canned food (CAN) balanced for sex and initial BW. Cats were fed ad libitum for 7 weeks, including one week before surgery (week 0) and 6 weeks after surgery (week 1-6). Daily dry matter intake (DMI), and weekly body weight (BW) and body condition score (BCS) was obtained. Feces were collected for measuring nutrient digestibility and concentrations of short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA). Physical pain and wound surface assessment were performed at week 1. Blood was also collected intermittently for measuring biochemical indices and untargeted metabolomics analysis. Results indicated that BW, BCS and daily DMI in CON group increased (P < 0.05) over time after castration, but were maintained relatively stable in CAN group. Cats in CAN group exhibited less pain-related behavior as reflected by lower score of comfort (P < 0.05) and vocalization (P < 0.10), improved wound surface assessment (P < 0.10), lower level of lipase (P < 0.10) and ratio of blood urea nitrogen/serum creatinine (BUN/SC; P < 0.05), and higher level of superoxide dismutase (SOD; P < 0.05) in week 1 than CON cats. Meanwhile, the CAN group had significantly higher concentration of immunoglobulin G (IgG) on days 5 and 7, and higher level of high-density lipoprotein cholesterol (HDL-C; P < 0.10) but lower triglyceride (TG; P < 0.05) than CON group on day 20 and 48. Fecal total and most individual SCFA increased significantly from week 1 to week 6 regardless of diet, but the increase of butyric acid over time only occurred in CON group (P < 0.05). Also, serum metabolomic analysis revealed differential metabolic pathways between the two groups. Overall, compared with the dry food, the canned food tested in our study promoted cat wound recovery by reducing pain and increasing immune and antioxidative capacity after sterilizing surgery, and helped to maintain healthy body condition in cats after castration.

Evaluation of urine concentrations of amoxicillin and clavulanate in cats

BACKGROUND

To characterize urinary isolates, the Clinical and Laboratory Standards Institute (CLSI) uses an amoxicillin breakpoint for cats based on plasma (not urine) drug concentrations (≤0.25 μg/mL), but a urine-specific breakpoint for dogs exists (≤8 μg/mL).

OBJECTIVES

To measure urine concentrations of amoxicillin and clavulanate after PO administration of amoxicillin-clavulanate to cats, and to suggest updated urine-specific susceptibility breakpoints for PO amoxicillin and amoxicillin-clavulanate in cats.

ANIMALS

Eleven healthy purpose-bred cats.

METHODS

Cats were given 3 62.5 mg doses of amoxicillin-clavulanate PO q12h. After the third dose, urine was collected over 28 hours, recording urination time and volume. At least 3 urine samples were collected per cat. Liquid chromatography with mass spectrometry was used to determine the urine concentrations of amoxicillin and clavulanate.

RESULTS

Amoxicillin concentrations were >8 μg/mL in all urine samples collected within 12 hours after administration (range, 31.6-1351 μg/mL), with means of 929 μg/mL (0-6 hours) and 532 μg/mL (6-12 hours). The mean half-life of amoxicillin in urine was 1.99 hours, and mean recovery was 30%. Clavulanate was detected in all urine samples, with mean half-life of 2.17 hours.

CONCLUSIONS AND CLINICAL IMPORTANCE

Orally administered amoxicillin-clavulanate resulted in urine amoxicillin concentrations above the cutoff (8 μg/mL) for wild-type Escherichia coli in all cats. Because urine-specific susceptibility testing breakpoints can be determined using urine concentrations, this information should allow new CLSI uropathogen susceptibility breakpoints for amoxicillin and amoxicillin-clavulanate in healthy cats, increasing the urine breakpoint from ≤0.25 to ≤8 μg/mL.

Validation of saliva and urine use and sampling time on the doubly labelled water method to measure energy expenditure, body composition and water turnover in male and female cats

Less invasive protocols are necessary to study energy expenditure (EE) of cats living in homes for expressing their normal living conditions. The present study compared sampling times and the use of saliva, urine and blood to measure 2H and 18O to apply the doubly labelled water method. In the first study, four cats were used to evaluate the enrichment (2, 4, 6, 7 and 8 h) and elimination (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 d) of 2H and 18O (subcutaneously injected). The maximum enrichment was after 5 h (R2 0·82) of injection, with an Ln linear elimination of both isotopes (P < 0·001; R2 0·99). The results of EE were similar, regardless of the sampling time used (P = 0·999). In the second study, seven male cats and seven female cats were used. Before and after isotope injection (5 h, 7 d, 10 d and 14 d), blood, saliva and urine were collected. Isotope enrichment was lower in urine (P < 0·05) and at the similar level in blood and saliva. Isotope elimination was similar for all fluids (P < 0·473). The EE calculated with blood and saliva was similar but higher for urine (P = 0·015). According to Bland-Altman statistics, blood and saliva presented low bias and high correlation (P < 0·001), but this was not observed for urine (P = 0·096). Higher EE was observed for male cats (384 (se 39) kJ/kg0·67 per d) than for female cats (337 (se 34) kJ/kg0·67 per d; P < 0·05). The sampling time for the method is flexible, and saliva can be used as a substitute for blood.

Effects of crude protein and sodium intake on water turnover in cats fed extruded diets

The comprehension of strategies to increase urine production may be important, especially in kibble diets to prevent urolithiasis in cats. The effects of increasing amounts of crude protein (CP) and sodium on the water turnover of cats were evaluated using the water balance (WB) method and the deuterium dilution technique. The study followed a randomized block design, with three blocks of eight cats, two cats per food type in each block, and six cats per food. Four extruded diets with different amounts of CP and sodium were evaluated (on DM basis): 28% CP and 0.58% sodium; 39% CP and 0.64% sodium; 52% CP and 0.76% sodium; and 64% CP and 0.87% sodium. Cats were individually housed in cages for 8 days to measure WB, urea excretion, and faecal and urine characteristics. Deuterium oxide was used to evaluate water turnover, and during the period cats were housed in a collective cattery. The data were analysed by an F test, and the means were compared by polynomial contrasts. The ɑ level of significance was set at 0.05. The methods were compared by Pearson correlation, and Bland and Altman analysis. The increase in the CP content elevated linearly the renal excretion of urea (p < .001), and, together with the higher sodium intake, elevated the renal solute load, which resulted in a linear increase in urine production and water intake (p < .01). The urine density, metabolic water, and faecal and insensible water losses did not differ (p > .05). The water flux increased linearly when using the deuterium method (p < .001), but the obtained values were 20.85 ± 11.11 ml/cat/day higher than those verified using the WB method (p = .001). Higher CP and sodium amounts in dry diets increased the urine production and water consumption of cats, and this can be explored as a possible option to increase urination.

Nutritional Management of Urolithiasis

Dietary management of urolithiasis in dogs and cats is designed to dissolve calculi when possible and/or reduce the risk of recurrence. The diet must reduce urine relative supersaturation for the particular salt in order to prevent crystallization. To decrease urinary concentrations of crystal precursors, increasing water intake is essential regardless of the stone type. Altering the amounts of dietary precursors of the stone and controlling urine pH is mostly effective for struvite, urate, xanthine, and cystine, but still subject to controversy for calcium oxalate. The investigation of underlying metabolic disorders and close monitoring of animals at risk is recommended.

The Fecal Microbiota in the Domestic Cat (Felis catus) Is Influenced by Interactions Between Age and Diet; A Five Year Longitudinal Study

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 the impacts of diets on gastrointestinal microbiota in young cats, the impacts of aging in older cats has not been explored. We followed a cohort of related kittens, maintained on two commercial diets (kibbled and canned) from weaning (8 weeks) to 5 years of age (260 weeks). We hypothesized that the long-term feeding of specific diet formats would (a) lead to microbial composition changes due to aging, (b) impact body composition, and (c) affect insulin sensitivity in the aging cat. We observed that both diet and age affected fecal microbial composition, and while age correlated with changes in body composition, diet had no effect on body composition. Similarly insulin sensitivity was not affected by age nor diet. 16S rRNA sequencing found unclassified Peptostreptococcaceae were prominent across all ages averaging 21.3% of gene sequence reads and were higher in cats fed canned diets (average of 25.7% of gene sequence reads, vs. 17.0% for kibble-fed cats). Age-related effects on body composition and insulin sensitivity may become apparent as the cats grow older; this study will continue to assess these parameters.

Cats and Carbohydrates: The Carnivore Fantasy?

The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues and led to unique digestive and metabolic peculiarities of carbohydrate metabolism. The domestic cat still closely resembles its wild ancestor. Although the carnivore connection of domestic cats is well recognised, little is known about the precise nutrient profile to which the digestive physiology and metabolism of the cat have adapted throughout evolution. Moreover, studies show that domestic cats balance macronutrient intake by selecting low-carbohydrate foods. The fact that cats evolved consuming low-carbohydrate prey has led to speculations that high-carbohydrate diets could be detrimental for a cat’s health. More specifically, it has been suggested that excess carbohydrates could lead to feline obesity and diabetes mellitus. Additionally, the chances for remission of diabetes mellitus are higher in cats that consume a low-carbohydrate diet. This literature review will summarise current carbohydrate knowledge pertaining to digestion, absorption and metabolism of carbohydrates, food selection and macronutrient balancing in healthy, obese and diabetic cats, as well as the role of carbohydrates in prevention and treatment of obesity and diabetes mellitus.