An Assessment of the Stability of the Canine Oral Microbiota After Probiotic Administration in Healthy Dogs Over Time.

The administration of an oral probiotic has been demonstrated to impact oral microbial diversity in humans but has not been examined in canines. The objective of this study was to test the hypothesis that oral probiotic administration would impact the oral microbiota of canines compared to control. Working canines in training (n = 13) were assigned to Test or Control groups and acclimated to one of three commercially available study diets utilizing common protein sources (Purina Pro Plan Savor lamb, Purina Pro Plan Sport chicken, Purina Pro Plan Focus salmon) for a minimum of 30 days prior to initiation of the study. Following acclimation, dogs in the Test group began a daily regimen of oral probiotic (Fortiflora® Purina, St. Louis, MO) top-dressed on their midday feeding. Control dogs received their midday feeding with no probiotic. All dogs were sampled once weekly via oral pediatric swabs across the 7-week study. Next generation sequencing (Illumina, MiSeq) was utilized to develop microbial profiles specific to treatment, diet, and time. Bacterial composition was dominated by eight phyla (Proteobacteria 43.8%, Bacteroidetes 22.5%, Firmicutes 18.9%, Actinobacteria 6.1%, Fusobacteria 3.6%, Gracilibacteria 2.1%, SR1 Absconditabacteria 1.5%, and Saccharibacteria 1.3%) representing more than 99% of the relative abundance of the microbial composition. Probiotic administration failed to impact relative abundance at any taxonomic level (P > 0.05). Similarly, no effect on the oral microbiota was measured for diet (P > 0.05). Comparison using a Jaccard Index demonstrate a consistent microbial profile over the 7-week study with no impact evidenced by study week (P = 0.19). The data also revealed a profile of ubiquitous taxa that were present across all dogs and all samples regardless of breed, sex, diet, treatment or other factors. These genera include Actinomyces, Corynebacterium, Capnocytophaga, Flavobacterium, Gemella, Abiotrophia, Streptococcus, and Frederiksenia. These data demonstrate the stability of canine oral microbiota over time.

Usefulness of muscle condition score and ultrasonographic measurements for assessment of muscle mass in cats with cachexia and sarcopenia.

OBJECTIVE: To compare muscle condition scores (MCSs) and muscle ultrasonographic measurements in cats with and without muscle loss and to evaluate repeatability and reproducibility of MCS assessment. ANIMALS: 40 cats of various ages, body condition scores (BCSs), and MCSs. PROCEDURES: A prospective cross-sectional study was conducted. Body weight, BCS, MCS, epaxial muscle height (EMH), vertebral epaxial muscle score (VEMS), and forelimb epaxial muscle score (FLEMS) were assessed in each cat. The MCS for each cat was assessed 3 separate times by each of 5 raters. RESULTS: The MCS was significantly correlated with EMH (r = 0.59), VEMS (r = 0.66), and FLEMS (r = 0.41). For MCS, the overall value of the κ coefficient for interrater agreement (reproducibility) was 0.43 and the overall value of the κ coefficient for intrarater agreement (repeatability) ranged from 0.49 to 0.76. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic measurements of muscle may be useful for assessing muscle loss in individual cats over time. However, for the cats of this study, no advantage was observed for assessment of VEMS or FLEMS over EMH. Substantial repeatability and moderate reproducibility were shown when MCS was used for assessment of muscle mass in cats. Prospective ultrasonographic studies are warranted to evaluate the usefulness of MCS and EMH assessment for evaluation of changes in muscle mass of cats over time.

The Effects of a Ketogenic Medium-Chain Triglyceride Diet on the Feces in Dogs With Idiopathic Epilepsy.

Consumption of diets containing medium chain triglycerides have been shown to confer neuroprotective and behavior modulating effects. We aimed to identify metabolic and microbiome perturbations in feces that are associated with consumption of a medium chain triglyceride ketogenic diet (MCT-KD) in dogs with idiopathic epilepsy. We used 16S rRNA gene sequencing to generate microbiome profiles and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to generate lipidomic profiles of canine feces. We made comparisons between the MCT-KD, standardized placebo diet and baseline pre-trial diet phases. Consumption of the MCT-KD resulted in a significant increase in the species richness (α-diversity) of bacterial communities found in the feces when compared to the baseline diet. However, phylogenetical diversity between samples (beta-diversity) was not affected by diet. An unnamed Bacteroidaceae species within genus 5-7N15 was identified by LEfSe as a potential biomarker associated with consumption of the MCT-KD, showing an increased abundance (p = 0.005, q = 0.230) during consumption of MCT-KD. In addition, unclassified members of families Erysipelotrichaceae (p = 0.013, q = 0.335) and Fusobacteriaceae (p = 0.022, q = 0.358) were significantly increased during MCT-KD consumption compared to baseline. Blautia sp. and Megamonas sp. instead were decreased during consumption of either placebo or MCT-KD (p = 0.045, q = 0.449, and p = 0.039, q = 0.449, respectively). Bacteroidaceae, including genus 5-7N15, have previously been associated with non-aggressive behavior in dogs. In addition, 5-7N15 is correlated in humans with Akkermansia, a genus known to be involved in the neuroprotective effect of ketogenic diets in mice models of seizures. Five metabolite features, tentatively identified as long chain triglycerides, were significantly higher after consumption of the placebo diet, but no unique features were identified after consumption of the MCT-KD. The data presented in this study highlight significant changes shown in both the fecal microbiome and lipidome as a result of consumption of the MCT-KD. Elucidating the global canine gut response to MCT consumption will improve our understanding of the potential mechanisms which confer anti-seizure and behavior modulating effects. Further studies should aim to characterize the gut microbiome of both dogs with epilepsy and healthy controls.

Evaluation of the use of muscle condition score and ultrasonographic measurements for assessment of muscle mass in dogs.

OBJECTIVE: To evaluate repeatability and reproducibility of muscle condition score (MCS) in dogs with various degrees of muscle loss; to compare MCS, muscle ultrasonographic measurements, and quantitative magnetic resonance (QMR) measurements; and to identify cutoff values for ultrasonographic measurements of muscle that can be used to identify dogs with cachexia and sarcopenia. ANIMALS: 40 dogs of various age, body condition score (BCS), and MCS. PROCEDURES: A prospective cross-sectional study was conducted. Body weight, BCS, QMR measurements, thoracic radiographic measurements, and muscle ultrasonographic measurements were assessed once in each dog. The MCS for each dog was assessed 3 separate times by 4 separate raters. RESULTS: For the MCS, overall κ for interrater agreement was 0.50 and overall κ for intrarater agreement ranged from 0.59 to 0.77. For both interrater and intrarater agreement, κ coefficients were higher for dogs with normal muscle mass and severe muscle loss and lower for dogs with mild and moderate muscle loss. The MCS was significantly correlated with age (r = -0.62), vertebral epaxial muscle score (VEMS; r = 0.71), forelimb epaxial muscle score (FLEMS; r = 0.58), and BCS (r = 0.73), and VEMS was significantly correlated (r = 0.84) with FLEMS. Cutoff values for identification of mild muscle loss determined by use of VEMS and FLEMS were 1.124 and 1.666, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: MCS had substantial repeatability and moderate reproducibility for assessment of muscle mass in dogs. Prospective studies of MCS, VEMS, and FLEMS for assessment of muscle mass in dogs are warranted.

Evaluation of skin turgor and capillary refill time as predictors of dehydration in exercising dogs.

OBJECTIVE To determine usefulness of skin turgor and capillary refill time (CRT) for predicting changes in hydration status of working dogs after a 15-minute exercise period. ANIMALS 9 exercise-conditioned working dogs between 8 and 108 months of age. PROCEDURES Skin tent time (SkTT; time for tented skin on the forehead to return to an anatomically normal position) and CRT (time for occluded mucous membrane capillary vessels to return to the color visible before occlusion) were measured on dogs in a field setting and by video review. Body weight (BW), SkTT, CRT, and core body temperature were measured before and after a 15-minute exercise period. Exercise challenge was performed on days 1 and 8. RESULTS Time (day 1 vs day 8) did not significantly affect results; therefore, data were pooled for the 2 trial days. Mean ± SE BW decreased (but not significantly) by 0.83 ± 0.27% after exercise. The SkTT increased significantly (both field setting and video review) after exercise. Correlation between SkTT results for the field setting and video review (r = 0.68) was significant. The CRT decreased (but not significantly) after exercise. CONCLUSIONS AND CLINICAL RELEVANCE Dogs became mildly dehydrated (mean BW loss, 0.83%) during a 15-minute exercise period, and the mild dehydration was evident as a visually detectable change in skin turgor. Monitoring the SkTT appeared to be a useful strategy for predicting small shifts in hydration status of dogs during exercise. The CRT decreased and was not a significant predictor of a change in hydration status.

Effects of a nutrient-enriched water with and without poultry flavoring on water intake, urine specific gravity, and urine output in healthy domestic cats fed a dry kibble diet.

OBJECTIVE To investigate water intake and urine measures in healthy cats provided free-choice access to a nutrient-enriched water with (NWP) or without (NW) added poultry flavoring offered at 3 different volumes in addition to tap water (TW). ANIMALS 36 domestic shorthair cats. PROCEDURES Control group cats (n = 4) received dry food with TW ad libitum throughout the study. Cats of the NW and NWP groups (n = 16/group) received the same food with TW only (period 1; 7 days) followed by TW and the assigned treatment ad libitum at 1X, 1.5X, and 2X the volume of TW consumed in period 1 during periods 2 (17 days), 3 (10 days), and 4 (10 days), respectively. Liquid consumption, food intake, and total water intake (from all sources) were measured; urine collected over 48 hours in each period was measured, and urine specific gravity (USG) was determined. Data were analyzed with mixed-effects models. RESULTS TW and food calorie intake were similar among groups in period 1; TW consumption by control cats did not differ during the study. Liquid consumed by drinking increased 18%, 57%, and 96% for the NWP group in periods 2, 3, and 4, respectively, with increases of 25% and 44% for the NW group in periods 3 and 4, respectively, compared with period 1 values for the same groups. Increased urine output and decreased USG were significantly associated with period and treatment. CONCLUSIONS AND CLINICAL RELEVANCE Increasing the volumes of NW or NWP offered to healthy cats led to increased free liquid consumption and was associated with greater urine output and dilution as measured by USG. Studies are warranted to determine whether these treatments provide health benefits for cats in need of greater water consumption.

Working Dogs Drinking a Nutrient-Enriched Water Maintain Cooler Body Temperature and Improved Pulse Rate Recovery After Exercise.

Exercise-related physiological changes were evaluated in hydrated, exercise-conditioned working dogs with free access to tap water (TW) with or without a nutrient-enriched water supplement (NW). Physiological samples and measures were collected before and after work-related field tasks in a warm and moderately humid ambient environment. In a cross-over design study, 12 dogs (age range 8-23 months) were evaluated on 3 separate occasions within each period with exercise bouts up to 30 min, on days -4, 3, and 11. Dogs were offered either ad libitum TW or portion-controlled NW daily plus ad libitum TW. Prior to and serially after exercise, pulse rate (PR), core (BTcore) and ear (BTear) temperature were recorded. Urine was collected first thing in the morning, whereas blood samples collected and body weight (BW) recorded pre- and immediately post exercise. Ambient temperature was above 21.7°C (71°F) and relative humidity ranged from 36 to 76%. Activity parameters, AM urine measures, post-exercise percent change of BW, resting PR and resting BTcore did not differ between treatment groups on any exercise day. At the completion of exercise, mean BTcore for all dogs ranged from 104.8 to 105.6°F. Immediate post-exercise BTear was always lower compared to BTcore and means ranged from 103.3 to 104.0°F. The effect of time was highly significant (P < 0.001) for both BT measures with both BTcore and BTear recovering to resting levels by 60 min post exercise. PR and several blood values showed a significant main effect of time. Over the recovery period, dogs in the NW group had lower mean BTear and PR by 0.6°F and 3.4 bpm, respectively. Daily ingestion of a NW in combination with free access to TW can reduce the post-exercise-related BTcore and BTear hyperthermia, and improve pulse rate recovery following exercise in this population of working dogs undergoing 30 min bout of exercise.

Effects of a nutrient-enriched water on water intake and indices of hydration in healthy domestic cats fed a dry kibble diet.

OBJECTIVE To evaluate the effects of drinking nutrient-enriched water (NW) on water intake and indices of hydration in healthy domestic cats fed a dry kibble diet ad libitum. ANIMALS 18 domestic shorthair cats. PROCEDURES Group-housed cats were assigned to tap water (TW; n = 9) or NW (9) groups. All cats received TW at baseline (days -7 to -1). No changes were made to the food-water regimen for the TW group. The NW group received NW instead of TW from days 0 through 10, then received TW and NW in separate bowls (days 11 through 56). Food intake was measured through day 10; liquid consumed by drinking was measured throughout the study. Blood and urine samples were collected at predetermined times for analyses; 48-hour urine collection (days 28 through 30 or 31 through 33) was performed to assess output volume and aid endogenous creatinine-based glomerular filtration rate (GFR) determination. Data were analyzed with linear mixed-effects models. RESULTS Baseline TW and calorie intake were similar between groups. The NW treatment was significantly associated with increased liquid consumption during the treatment phase. Mean urine output was significantly higher in the NW group (15.2 mL/kg/d) than in the TW group (10.3 mL/kg/d). Mean GFR (1.75 vs 1.87 mL/min/kg, respectively) did not differ between groups. Effects of treatment and time were each significant for urine specific gravity and osmolality and urine creatinine, phosphate, and urea nitrogen concentrations, with lower values for the NW group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that consumption of the NW can increase liquid intake and improve measures of hydration in healthy cats. These effects may offer health benefits to some cats in need of greater water consumption.

Total Water Intake and Urine Measures of Hydration in Adult Dogs Drinking Tap Water or a Nutrient-Enriched Water.

Water intake and urine measures were evaluated in dogs offered tap water (TW) or a nutrient-enriched water (NW) supplement while fed dry food with ad libitum TW in a bucket. Baseline (day-7) urine specific gravity (USG) was analyzed from healthy, adult small breed dogs (n = 21; 2-11 years). Dogs (N = 16) were selected with ≥1.015 USG, then equally divided into 2 groups balanced for USG. Groups received either TW or NW in a bowl for 56 days. Dose for each dog was 0.5:1 water-to-calorie ratio (mL:kcal ME/d) from days 1-49 to evaluate sustained intake of a moderate volume, or 2:1 water-to-calorie ratio from days 50-56 to evaluate short-term intake of a large volume, based on baseline food calorie intake. Daily food calorie and total liquid intake (TLI; g/d; sum of NW or TW in a bowl and bucket water) was used to calculate weekly intake. USG was measured on days -7, 14, 42, 56. Calorie intake was not different (P > 0.49). A significant (P < 0.001) time-by-treatment interaction resulted for TLI with baseline similar between groups and no difference between weeks for the TW group. Following baseline, NW group had increased (P < 0.05) TLI every week, except for week 2 (P = 0.07). A significant (P < 0.002) time-by-treatment interaction resulted for USG, with baseline similar between groups and no difference between sampling days for the TW group (varied by ≤ 0.006 g/mL), whereas NW group was lower (P < 0.01) on days 42 (1.018 g/mL) and 56 (1.014 g/mL) vs. baseline (1.026 g/mL). This study indicates that all dogs offered the NW supplement increased their TLI and produced a more dilute urine, which suggests an improvement in indices associated with chronic hydration.

Environmental and Physiological Factors Associated With Stamina in Dogs Exercising in High Ambient Temperatures.

This IACUC approved study was performed to evaluate the environmental, physiological, and hematological components that contribute to stamina following successive bouts of exercise that included searching (5-min), agility (5-min), and ball retrieve (<10-min). Regularly exercised dogs (N = 12) were evaluated on five separate occasions. The population consisted of eight males and four females ranging in age from 8 to 23 months, which included six Labrador retrievers, three German shepherds, and one each English springer spaniel, German wirehaired pointer, and Dutch shepherd. The exercise period was up to 30 min with 5 min of intermittent rest between the exercise bouts or until a designated trainer determined that the dog appeared fatigued (e.g., curled tongue while panting, seeking shade, or voluntary reluctance to retrieve). At the end of the exercise period, pulse rate (PR), core temperature, blood lactate, and venous blood gas were collected. The median outdoor temperature was 28.9°C (84°F) (IQR; 27.2-30°C/81-86°F) and median humidity was 47% (IQR; 40-57%). Median duration of exercise was 27 min (IQR; 25-29). No dog showed signs of heat stress that required medical intervention. The components used to measure stamina in this study were total activity, post-exercise core body temperature (CBT), and increase in CBT. When controlling for breed, total activity, as measured by omnidirectional accelerometer device, could be predicted from a linear combination of the independent variables: pre-exercise activity (p = 0.008), post-exercise activity (p < 0.001), outdoor temperature (p = 0.005), reduction in base excess in extracellular fluid compartment (BEecf) (p = 0.044), and decrease in TCO2 (p = 0.005). When controlling for breed and sex, increase in CBT could be predicted from a linear combination of the independent variables: study day (p = 0.005), increase in PR (p < 0.001), increase in lactate (p = 0.001), reduction in BEecf (p = 0.031), increase in glucose (p = 0.044), increase in hematocrit (p = 0.032), and increase in hemoglobin (p = 0.038). This study suggests that the influence of outdoor temperature, pre- and post-exercise activity, and the metabolic parameters are important components of stamina associated with exertion.

The effects of a post-exercise carbohydrate and protein supplement on repeat performance, serum chemistry, insulin and glucagon in competitive weight-pulling dogs.

The physiological demands of weight-pulling dogs have yet to be investigated. Two groups of competitive weight-pulling dogs both underwent two identical pull series 3 h apart. The control group (n 8) was compared with a group fed a rapidly digestible carbohydrate and protein supplement after the first pull series (n 9). Blood was drawn before and after each pull series as well as at 15 and 30 min after the first pull series finished. Biochemistry values remained unremarkable throughout the study in both groups regardless of supplementation or exercise over time. Lactic acid showed mild significant increases post-exercise (2·1 (sd 1·2) mmol/l) compared with baseline (1·4 (sd 0·3) mmol/l; P = 0·03) after the initial pull series. When examining the effects of time there was a significant increase in insulin from baseline (median of 10·8 (range 6·8-17·4) µIU/ml) compared with 30 min after supplementation (17·0 (range 8·1-33·0) µIU/ml) and at 3 h after supplementation (19·2 (range 9·7-53·4) µIU/ml). In the treatment group there was also a time effect, with glucagon being elevated from baseline (median of 100 (range 79-115) pg/ml) compared with 30 min after supplementation (114 (range 90-183) pg/ml) and after the second pull series (131 (range 107-152) pg/ml). Evaluation of each dog's ability to pull the same or greater amount of weight on the second pull series revealed no significant differences. In conclusion, weight-pulling dogs have mild elevations in lactate reflecting little anaerobic metabolism compared with other canine sprinting athletes; hormonal changes associated with carbohydrate absorption are reflected within the treatment group, and supplementation had no effect on performance.

Eye and Ear Temperature Using Infrared Thermography Are Related to Rectal Temperature in Dogs at Rest or With Exercise.

Rectal body temperature (BT) has been documented in exercising dogs to monitor thermoregulation, heat stress risk, and performance during physical activity. Eye (BTeye) and ear (BTear) temperature measured with infrared thermography (IRT) were compared to rectal (BTrec) temperature as the reference method and assess alternative sites to track hyperthermia, possibly to establish BTeye IRT as a passive and non-contact method. BT measures were recorded at 09:00, 11:30, 12:30, and 02:30 from Labrador Retrievers (N = 16) and Beagles (N = 16) while sedentary and with 30-min play-exercise (pre- and 0, 15, 30-min post-exercise). Total exercise locomotor activity counts were recorded to compare relative intensity of play-exercise between breeds. BTrec, BTeye, and BTear were measured within 5 min of the target time. Each BT method was analyzed by analysis of variance for main effects of breed and time. Method differences were compared using Bland-Altman plots and linear regression. Sedentary BT differed by breed for BTrec (p < 0.0001), BTear (p < 0.0001), and BTeye (p = 0.06) with Labs having on average 0.3-0.8°C higher BT compared to Beagles. Readings also declined over time for BTeye (p < 0.0001) and BTear (p < 0.0001), but not for BTrec (p = 0.63) for both breeds. Total exercise (30-min) activity counts did not differ (p = 0.53) between breeds. Time and breed interaction was significant in response to exercise for both BTrec and BTear (p = 0.035 and p = 0.005, respectively), with a marginal interaction (p = 0.09) for BTeye. All the three methods detected hyperthermia with Labs having a higher increase compared to Beagles. Both BTear and BTeye were significantly (p < 0.0001) related to BTrec in all dogs with sedentary or exercise activity. The relationship between BTeye and BTrec improved when monitoring exercise hyperthermia (r = 0.674) versus measures at rest (r = 0.381), whereas BTear was significantly related to BTrec regardless of activity (r = 0.615-0.735). Although BT readings were significantly related, method bias (p < 0.02) was observed for BTeye to slightly underestimate BTrec, whereas no bias was observed between BTear and BTrec. This study demonstrates that IRT technology effectively measures both ear and eye temperature and enables effective monitoring of BT changes at rest, with exercise, and between breeds. However, ear, and not eye, temperature is a better reflection of rectal temperature.

Diurnal changes in core body temperature, day/night locomotor activity patterns, and actigraphy-generated behavioral sleep in aged canines with varying levels of cognitive dysfunction.

Core body temperature (CBT) rhythm, locomotor activity, and actigraphy-sleep were evaluated in geriatric dogs with cognitive dysfunction. Dogs (n=33; 9-16 yrs) performed a spatial working memory task and divided into three memory groups: Low, Moderate, and High, with subsequent evaluation of learning and attention. Rectal CBT was recorded 6 times over a 17.5 h period and Actiwatch® activity monitoring system for 5 days while housed indoors with 12 h light/dark schedule. Rhythm of daily activity data was evaluated using the traditional cosinor analysis and generation of non-parametric measures of interdaily stability, intradaily variability, and relative amplitude. CBT differed with time (F (5, 130)=11.36, p<0.001), and was the highest at 19:00C. CBT at 19:00 was positively related (p<0.01) to memory (r(31)=0.50) and 3-domain cognitive performance index (memory, learning, attention; r(31)=0.39). Total daytime or night-time activity did not differ between memory groups, but hourly counts at 8:00 were positively related (p<0.05) to memory (r(31)=0.52), learning (r(31)=0.36), and 3-domain cognitive performance index (r(31)=0.53). There were no significant differences between age or memory groups for any circadian rhythm measures. Daytime naps were inversely related to memory accuracy (r(31)=-0.39; p<0.05) and BT at 15:00 (r(30)=-0.51; p<0.01). Lower peak BT and increased napping may predict some aspects of cognitive performance of working memory, learning, and/or attention processes in these geriatric dogs, but minimal diurnal rhythm disruption of locomotor activity is observed when these cognitive processes decline.

Effects of postexercise feeding of a supplemental carbohydrate and protein bar with or without astaxanthin from Haematococcus pluvialis to exercise-conditioned dogs.

OBJECTIVE: To characterize the postprandial nutrient profiles of exercise-conditioned dogs fed a supplemental carbohydrate and protein bar with or without astaxanthin from Haematococcus pluvialis immediately after exercise. ANIMALS: 34 exercise-conditioned adult Husky-Pointer dogs. PROCEDURES: The study had 2 phases. During phase 1, postprandial plasma glucose concentration was determined for dogs fed a bar containing 25% protein and 18.5% or 37.4% maltodextrin plus dextrin (rapidly digestible carbohydrate; RDC), or dry kibble (30% protein and 0% RDC) immediately after exercise. During phase 2, dogs were exercised for 3 days and fed a bar (25% protein and 37.4% RDC) with (CPA; n = 8) or without (CP; 8) astaxanthin or no bar (control; 8) immediately after exercise. Pre- and postexercise concentrations of plasma biochemical analytes and serum amino acids were determined on days 1 and 3. RESULTS: Phase 1 postexercise glucose concentration was increased when dogs were provided the 37.4% RDC bar, but not 0% or 18.5% RDC. On day 3 of phase 2, the CPA group had the highest pre-exercise triglyceride concentration and significantly less decline in postexercise glucose concentration than did the CP and control groups. Mean glucose concentration for the CP and CPA groups was significantly higher than that for the control group between 15 and 60 minutes after bar consumption. Compared to immediately after exercise, branched-chain amino acid, tryptophan, leucine, and threonine concentrations 15 minutes after exercise were significantly higher for the CP and CPA groups, but were lower for the control group. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs fed a bar with 37.4% RDCs and 25% protein immediately after exercise had increased blood nutrient concentrations for glycogen and protein synthesis, compared with control dogs.

Cognitive domains in the dog: independence of working memory from object learning, selective attention, and motor learning.

Cognition in dogs, like in humans, is not a unitary process. Some functions, such as simple discrimination learning, are relatively insensitive to age; others, such as visuospatial learning can provide behavioral biomarkers of age. The present experiment sought to further establish the relationship between various cognitive domains, namely visuospatial memory, object discrimination learning (ODL), and selective attention (SA). In addition, we also set up a task to assess motor learning (ML). Thirty-six beagles (9-16 years) performed a variable delay non-matching to position (vDNMP) task using two objects with 20- and 90-s delay and were divided into three groups based on a combined score (HMP = 88-93 % accuracy [N = 12]; MMP = 79-86 % accuracy [N = 12]; LMP = 61-78 % accuracy [N = 12]). Variable object oddity task was used to measure ODL (correct or incorrect object) and SA (0-3 incorrect distractor objects with same [SA-same] or different [SA-diff] correct object as ODL). ML involved reaching various distances (0-15 cm). Age did not differ between memory groups (mean 11.6 years). ODL (ANOVA P = 0.43), or SA-same and SA-different (ANOVA P = 0.96), performance did not differ between the three vDNMP groups, although mean errors during ODL was numerically higher for LMP dogs. Errors increased (P < 0.001) for all dogs with increasing number of distractor objects during both SA tasks. vDNMP groups remained different (ANOVA P < 0.001) when re-tested with vDNMP task 42 days later. Maximum ML distance did not differ between vDNMP groups (ANOVA P = 0.96). Impaired short-term memory performance in aged dogs does not appear to predict performance of cognitive domains associated with object learning, SA, or maximum ML distance.

Melatonin identified in meats and other food stuffs: potentially nutritional impact.

Melatonin has been identified in primitive photosynthetic bacteria, fungi, plants, and animals including humans. Vegetables, fruits, cereals, wine, and beers all contain melatonin. However, the melatonin content in meats has not been reported previously. Here, for the first time, we report melatonin in meats, eggs, colostrum, and in other edible food products. The levels of melatonin measured by HPLC, in lamb, beef, pork, chicken, and fish, are comparable to other food stuffs (in the range of ng/g). These levels are significantly higher than melatonin concentrations in the blood of vertebrates. As melatonin is a potent antioxidant, its presence in the meat could contribute to shelf life duration as well as preserve their quality and taste. In addition, the consumption of these foods by humans or animals could have health benefits considering the important functions of melatonin as a potent free radical scavenger and antioxidant.

Noninvasive measurements of body composition and body water via quantitative magnetic resonance, deuterium water, and dual-energy x-ray absorptiometry in cats.

OBJECTIVE: To compare quantitative magnetic resonance (QMR), dual-energy x-ray absorptiometry (DXA), and deuterium oxide (D2O) dilution methods for measurement of total body water (TBW), lean body mass (LBM), and fat mass (FM) in healthy cats and to assess QMR precision and accuracy. ANIMALS: Domestic shorthair cats (58 and 32 cats for trials 1 and 2, respectively). PROCEDURES: QMR scans of awake cats performed with 2 units were followed by administration of D2O tracer (100 mg/kg, PO). Cats then were anesthetized, which was followed by QMR and DXA scans. Jugular blood samples were collected before and 120 minutes after D2O administration. RESULTS: QMR precision was similar between units (coefficient of variation < 2.9% for all measures). Fat mass, LBM, and TBW were similar for awake or sedated cats and differed by 4.0%, 3.4%, and 3.9%, respectively, depending on the unit. The QMR minimally underestimated TBW (1.4%) and LBM (4.4%) but significantly underestimated FM (29%), whereas DXA significantly underestimated LBM (9.2%) and quantitatively underestimated FM (9.3%). A significant relationship with D2O measurement was detected for all QMR (r(2) > 0.84) and DXA (r(2) > 0.84) measurements. CONCLUSIONS AND CLINICAL RELEVANCE: QMR was useful for determining body composition in cats; precision was improved over DXA. Quantitative magnetic resonance can be used to safely and rapidly acquire data without the need for anesthesia, facilitating frequent monitoring of weight changes in geriatric, extremely young, or ill pets. Compared with the D2O dilution method, QMR correction equations provided accurate data over a range of body compositions.

Noninvasive measurements of body composition and body water via quantitative magnetic resonance, deuterium water, and dual-energy x-ray absorptiometry in awake and sedated dogs.

OBJECTIVE: To compare quantitative magnetic resonance (QMR), dual-energy x-ray absorptiometry (DXA), and deuterium oxide (D2O) methods for measurement of total body water (TBW), lean body mass (LBM), and fat mass (FM) in healthy dogs and to assess QMR accuracy. ANIMALS: 58 Beagles (9 months to 11.5 years old). PROCEDURES: QMR scans were performed on awake dogs. A D2O tracer was administered (100 mg/kg, PO) immediately before dogs were sedated, which was followed by a second QMR or DXA scan. Jugular blood samples were collected before and 120 minutes after D2O administration. RESULTS: TBW, LBM, and FM determined via QMR were not significantly different between awake or sedated dogs, and means differed by only 2.0%, 2.2%, and 4.3%, respectively. Compared with results for D2O dilution, QMR significantly underestimated TBW (10.2%), LBM (13.4%), and FM (15.4%). Similarly, DXA underestimated LBM (7.3%) and FM (8.4%). A significant relationship was detected between FM measured via D2O dilution and QMR (r(2) > 0.89) or DXA (r(2) > 0.88). Even though means of TBW and LBM differed significantly between D2O dilution and QMR or DXA, values were highly related (r(2) > 0.92). CONCLUSIONS AND CLINICAL RELEVANCE: QMR was useful for determining body composition in dogs and can be used to safely and rapidly acquire accurate data without the need for sedation or anesthesia. These benefits can facilitate frequent scans, particularly in geriatric, extremely young, or ill pets. Compared with the D2O dilution method, QMR correction equations provided accurate assessment over a range of body compositions.