Nutrient digestibility and fecal characteristics,microbiota, and metabolites in dogs fed human-grade foods

Human-grade (HG) pet foods are commercially available, but they have not been well studied. Our objective was to determine the apparent total tract digestibility (ATTD) of HG pet foods and evaluate their effects on fecal characteristics, microbiota, and metabolites, serum metabolites, and hematology of dogs. Twelve dogs (mean age = 5.5 ± 1.0; BW = 11.6 ± 1.6 kg) were used in a replicated 4 × 4 Latin square design (n = 12/treatment). The diets included 1) Chicken and Brown Rice Recipe (extruded; Blue Buffalo); 2) Roasted Meals Tender Chicken Recipe (fresh; Freshpet); 3) Beef and Russet Potato Recipe (HG beef; JustFoodForDogs); and 4) Chicken and White Rice Recipe (HG chicken; JustFoodForDogs). Each period consisted of 28 d, with a 6-d diet transition phase, 16 d of consuming 100% of the diet, a 5-d phase for fecal collection, and 1 d for blood collection. All data were analyzed using the Mixed Models procedure of SAS 9.4. Dogs fed the extruded diet required a higher (P < 0.05) daily food intake (dry matter basis, DMB) to maintain BW. The ATTD of dry matter (DM), organic matter (OM), energy, and acid-hydrolyzed fat (AHF) were greater (P < 0.05) in dogs fed the HG diets than those fed the fresh diet, and greater (P < 0.05) in dogs fed the fresh diet than those fed the extruded diet. Crude protein ATTD was lower (P < 0.05) for dogs fed the extruded diet than those fed all other diets. Dogs fed the extruded diet had greater (P < 0.05) fecal output (as-is; DMB) than dogs fed fresh (1.5–1.7 times greater) or HG foods (2.0–2.9 times greater). There were no differences in fecal pH, scores, and metabolites, but microbiota were affected by diet. Dogs fed HG beef had higher (P < 0.05) relative abundance of Bacteroidetes and lower (P < 0.05) relative abundance of Firmicutes than dogs fed the fresh or HG chicken diets. The Actinobacteria, Fusobacteria, Proteobacteria, and Spirochaetes phyla were unchanged (P > 0.05), but diet modified the relative abundance of nearly 20 bacterial genera. Similar to previous reports, these data demonstrate that the fecal microbiota of dogs fed HG or fresh diets is markedly different than those consuming extruded diets, likely due to ingredient, nutrient, and processing differences. Serum metabolites and hematology were not greatly affected by diet. In conclusion, the HG pet foods tested resulted in significantly reduced fecal output, were highly digestible, maintained fecal characteristics, serum chemistry, and hematology, and modified the fecal microbiota of dogs.     

Effect of different starch sources in a raw meat-based diet on fecal microbiome in dogs housed in a shelter

A dietary intervention study was assessed to determine if different sources of starch in homemade diets could significantly modify fecal microbiome of dogs. Twenty-seven adult dogs were enrolled and fed a diet based on a mixture of rice and pasta with fresh raw meat (CD). After 90 d, 8 dogs continued to receive CD diet, 10 dogs received a diet made of a raw meat and a complementary food with rice as the main source of starch (B1), and 9 dogs were fed a diet with the same raw meat and a complementary food with potato as the main source of starch (B2). Samples of feces were collected from each dog in the mornings at the beginning of the study and after 15 d and analyzed for pH, ammonia N (N–NH₃) and total N, short chain fatty acids (SCFA) and lactic acid. Relative abundance of fecal microbiota was assessed by sequencing and annotating the V3–V4 regions of the 16S rRNA. Total starch intake was similar between diets but differed in the in vitro rate digestion and in the resistant starch, which was higher in B2 than in B1 and CD diets. Dogs fed B2 diet showed lower (P < 0.05) N–NH₃ and pH but higher (P < 0.05) molar proportion of lactic acid. Linear discriminant analysis of the genera relative abundances indicated a significant (P < 0.01) increase of SMB53 genus at the end of the study in B1 diet and of Megamonas genus in B1 and B2 diets in comparison to CD diet. These results suggest that changes of starch source in a raw meat-based diet have limited effects on fecal microbiome in healthy dogs, but underline a high variability of microbiota among dogs.     

Assessing the severity of canine pancreatitis

The objective of this study was to determine whether laboratory testing currently available is able to provide prognostic information in canine pancreatitis. A prospective study of dogs with naturally occurring pancreatitis was undertaken. Twenty-two cases with histologically confirmed pancreatic inflammation were included in the study. Each dog had routine haematology parameters, serum biochemistry (including lipase and amylase), serum trypsin-like immunoreactivity and trypsinogen activation peptides (TAP) in urine and plasma measured. Twelve of the dogs were classified as having severe disease. These dogs had statistically significant increases in urinary TAP-creatinine ratio (UTCR) measurement, serum lipase, serum phosphate and serum creatinine concentrations. Additionally dogs with severe pancreatitis had significantly decreased urine specific gravity levels. The most sensitive and specific test to assess the severity of pancreatitis was the measurement of UTCR.     

犬用配方羊奶粉对比格幼犬生长性能和肠道菌群的影响

为了探究配方羊奶粉对比格幼犬生长性能与肠道菌群的影响,选取12只15日龄比格犬,随机分为对照组和羊奶粉组,每组6只,对照组幼犬由母犬母乳喂养,羊奶粉组幼犬饲喂足量配方羊奶粉,每3d测量体重并计算体重增长,18 d后采集血样进行血常规、血清生化、免疫因子指标检测,采集粪样进行肠道菌群测序.结果 显示:相比于对照组,羊奶粉...     

Evaluation of a colonic lavage solution to prepare the colon of the dog for colonoscopy

Ten dogs were given 3 different doses (60, 80, and 100 ml/kg of body weight) of a commercial colonic lavage solution in 2 equally divided doses, 2 to 4 hours apart. The degree of colonic cleanliness was evaluated subjectively, using a numbered scoring system (1 = clean to 4 = excessive fecal material). Systemic and metabolic effects were assessed by comparing body weight, PCV, total protein concentration, serum osmolality, and urine specific gravity before and 24 hours after administration of the high-dose solution. The lowest mean cleanliness score (1.6) was obtained with the 80 ml/kg dose (P less than 0.001). The solution had no effect on any measurement except urine specific gravity (P = 0.036). Oral administration of a colonic lavage solution in a divided total dose of 80 ml/kg is a safe and effective method of large-intestine preparation in the dog.     

Digestibility,fecal characteristics,and plasma glucose and urea in dogs fed a commercial dog food once or three times daily

Digestibility, fecal characteristics, and levels of glucose and urea in the plasma were determined in 8 dogs that received 2 different dog foods once or 3 times daily. One dog food (A) was 5 times more expensive than the other (B). Fecal pH and consistency, digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and crude fiber (CF) were determined. Blood samples were taken from 30 min before to 60 min after a meal. Digestibilities of DM, OM, and CP, and fecal consistency were higher, and daily fecal excretion and fecal pH were lower when dogs were fed food A (P < 0.001). The feeding schedule had no effect on plasma glucose and urea. Neither feeding frequency nor food × frequency interactions was significant for the parameters studied.     

The dynamics of the piglet gut microbiome during the weaning transition in association with health and nutrition

Background: Understanding the composition of the microbial community and its functional capacity during weaning is important for pig production as bacteria play important roles in the pig's health and growth performance. However,limited information is available regarding the composition and function of the gut microbiome of piglets in early-life.Therefore, we performed 16 S rRNA gene and whole metagenome shotgun sequencing of DNA from fecal samples from healthy piglets during weaning to measure microbiome shifts, and to identify the potential contribution of the early-life microbiota in shaping piglet health with a focus on microbial stress responses, carbohydrate and amino acid metabolism.Results: The analysis of 16 S rR NA genes and whole metagenome shotgun sequencing revealed significant compositional and functional differences between the fecal microbiome in nursing and weaned piglets. The fecal microbiome of the nursing piglets showed higher relative abundance of bacteria in the genus Bacteroides with abundant gene families related to the utilization of lactose and galactose. Prevotel a and Lactobacil us were enriched in weaned piglets with an enrichment for the gene families associated with carbohydrate and amino acid metabolism. In addition, an analysis of the functional capacity of the fecal microbiome showed higher abundances of genes associated with heat shock and oxidative stress in the metagenome of weaned piglets compared to nursing piglets.Conclusions: Overal, our data show that microbial shifts and changes in functional capacities of the piglet fecal microbiome resulted in potential reductions in the effects of stress, including dietary changes that occur during weaning.These results provide us with new insights into the piglet gut microbiome that contributes to the growth of the animal.     

妊娠后期与泌乳期母猪肠道微生物多样性研究

本试验旨在研究妊娠后期和泌乳期母猪肠道微生物多样性。选取6头健康、背膘厚与分娩日期相近的第2胎次大白母猪,分别于妊娠期第93天(G93)和第100天(G100)以及泌乳期第14天(L14)和第21天(L21)取其直肠粪样,用Illumina HiSeq测序技术分析微生物多样性。结果显示:1)从6头母猪的24份样品中共获得875732条有效序列、1298个操作分类单元(OTU),分别有1181个和429个OTU可以注释到门和属水平。2)在alpha多样性方面,与G93和G100时相比,L14和L21时的OTU数显著下降(P<0.05);L21时的Chao1、Observed species和Shannon指数显著低于G100时(P<0.05);与G93时相比,L21时的Simpson指数显著降低(P<0.05)。3)在beta多样性方面,G93和G100时的微生物组成相似,L14和L21时的微生物组成相似,但妊娠后期与泌乳期肠道微生物组成差异较大。4)4个时间点共有微生物OTU 809个,可分别注释到13个门和69个属。5)在门水平上,4个时间点的优势菌门均为厚壁菌门、拟杆菌门和螺旋菌门,这3个门的菌数占各时间点总菌数的93.20%以上;与G93时相比,L21时广古菌门的相对丰度显著降低(P<0.05)。6)在属水平上,4个时间点的优势菌属均是普雷沃氏菌属、乳酸菌属和密螺旋体属;乳酸菌属的相对丰度在L21时显著高于G93时(P<0.05);梭状芽胞杆菌属ⅩⅣa的相对丰度在L14和L21时显著低于G93时(P<0.05)。由此可见,与妊娠后期相比,泌乳期母猪肠道微生物多样性下降;妊娠后期与泌乳期母猪肠道的优势菌门均为厚壁菌门、拟杆菌门和螺旋菌门,其微生物组成相对稳定。     

一例犬糖尿病的诊断与治疗

犬糖尿病是犬的常发疾病,其临床症状为多饮、多食、多尿、体重下降。持续的血糖升高导致机体代谢紊乱,出现如白内障、胰腺炎、肾上腺皮质机能亢进等继发症,对犬的生活质量及生命健康造成严重的威胁。论文对1例Ⅰ型糖尿病犬进行详细分析,通过测量血糖、尿糖确诊为糖尿病,并通过实验室检查包括血细胞计数、血清生化检测及血气分析,排除并发症。治疗过程与主人共同配合,使用外源性胰岛素结合食物疗法与运动疗法。目前该犬的血糖稳定并接近正常值,身体状况得到改善,生活质量提高,主人对治疗效果满意。持续治疗方法是根据犬的身体情况及血糖变化适当调整胰岛素的剂量。     

Biologic activity of dirlotapide, a novel microsomal triglyceride transfer protein inhibitor, for weight loss in obese dogs

Dirlotapide is a novel microsomal triglyceride transfer protein inhibitor intended for the treatment and management of obesity in dogs. The biologic effects of dirlotapide, weight loss, decreased food intake, increased fecal fat, decreased serum cholesterol, and body composition, were evaluated in a controlled, blinded study. Sixteen obese beagles were randomized to treatment with placebo ( n  = 4) or dirlotapide ( n  = 12) following a 2-week acclimation period in which baseline data were collected. The dirlotapide dose, adjusted to produce weight loss for 3 months and then stabilize body weight for 1 month (weight management), produced a significant difference (expressed as a percentage of baselines) in weekly weight loss, food intake, fecal fat, serum cholesterol concentration, and body composition (measured by dual energy X-ray absorptiometry) compared with placebo treatment ( P  < 0.05). The initial dirlotapide dosage of 0.5 mg/kg (10 times the initial label dose) resulted in a high rate of weight loss (3.3% weekly) and anorexia, emesis, and loose stools for some dogs. A 25% dose reduction (mean dosage: 0.36 mg/kg) followed by biweekly 25% dose adjustments based on individual weight loss, produced 1–2% weekly weight loss and total weight loss of 18.8% in 12 weeks at a final mean dosage of 0.41 mg/kg (range: 0.15–0.60); a dosage range of 0.10–0.34 mg/kg stabilized body weight. Body weight changes for placebo-treated dogs were −0.8% to +0.9% weekly; total weight gain during the weight loss phase was 10.6%. No apparent change in food intake, percentage of fecal fat, and serum cholesterol was observed in the placebo group. Food intake and body weight increased when dirlotapide was discontinued. Dirlotapide produced weight loss by both reducing appetite (about 90% of the weight loss activity) and by increasing fecal fat excretion (about 10% of the weight loss activity).     

Effect of a novel animal milk oligosaccharide biosimilar on macronutrient digestibility and gastrointestinal tolerance,fecal metabolites,and fecal microbiota of healthy adult cats

GNU100 is a novel animal milk oligosaccharide (AMO) biosimilar. In a recent in vitro fermentation study, GNU100 was shown to be fermentable by feline gastrointestinal microbiota and lead to increased short-chain fatty acid production. Our objectives herein were to evaluate the palatability, safety, and gastrointestinal tolerance of GNU100 in healthy adult cats. Exploratory end-points were measured to assess utility. In study 1, 20 adult cats were used to test the palatability of diets containing 0% or 1% GNU100. In study 2, 32 (mean age = 1.9 yr; mean body weight = 4.6 kg) male (n = 12) and female (n = 20) adult cats were used in a completely randomized design. After a 2-wk baseline, cats were assigned to one of the following treatment groups and fed for 26 wk: control (CT, no GNU100), low dose (LD, 0.5% GNU100), medium dose (MD, 1.0% GNU100), and high dose (HD, 1.5% GNU100). On weeks 2, 4, and 26, fresh fecal samples were collected for the measurement of stool quality and immune and inflammatory markers and on weeks 2 and 4 for microbiota and metabolites. On week 4, total feces were collected to measure apparent total tract macronutrient digestibility. On weeks 2, 4, and 26, blood samples were collected for serum chemistry, hematology, and inflammatory marker measurement. The palatability test showed that 1% GNU100 was strongly preferred (P < 0.05), with GNU100 having a 17.6:1 consumption ratio compared with control. In the long-term study, all cats remained healthy, without any signs of gastrointestinal intolerance or illness. All diets were well accepted, resulting in similar (P > 0.05) food intake, fecal characteristics, immunoglobulin A, and calprotectin, and dry matter, organic matter, fat, and crude protein digestibilities. Fecal butyrate was greater (P = 0.02) in cats fed HD than cats fed LD or MD. Fecal indole was lower (P = 0.02) in cats fed HD than cats fed LD. Cats fed CT had a higher (P = 0.003) relative abundance of Actinobacteria than cats fed LD. The relative abundance of Peptococcus was impacted by diet and time. At 4 wk, Campylobacter was lower in fecal samples of cats fed HD. Overall, the data suggest that dietary GNU100 supplementation was highly palatable, well tolerated, did not cause detrimental effects on fecal quality or nutrient digestibility, increased fecal butyrate concentrations, and reduced fecal indole concentrations, supporting the safety of GNU100 for inclusion in feline diets and suggesting potential benefits on gastrointestinal health of cats.     

Evaluation of a novel animal milk oligosaccharide biosimilar: macronutrient digestibility and gastrointestinal tolerance,fecal metabolites,and fecal microbiota of healthy adult dogs and in vitro genotoxicity assays

Milk oligosaccharides (MO) are bioactive compounds in mammalian milk that provide health benefits to neonates beyond essential nutrients. GNU100, a novel animal MO biosimilar, was recently tested in vitro, with results showing beneficial shifts in microbiota and increased short-chain fatty acid (SCFA) production, but other effects of GNU100 were unknown. Three studies were conducted to evaluate the safety, palatability, and gastrointestinal (GI) tolerance of GNU100. In study 1, the mutagenic potential of GNU100 was tested using a bacterial reverse mutation assay and a mammalian cell micronucleus test. In study 2, palatability was assessed by comparing diets containing 0% vs. 1% GNU100 in 20 adult dogs. In study 3, 32 adult dogs were used in a completely randomized design to assess the safety and GI tolerance of GNU100 and explore utility. Following a 2-wk baseline, dogs were assigned to one of four treatments and fed for 26 wk: 0%, 0.5%, 1%, and 1.5% GNU100. On weeks 2, 4, and 26, fresh fecal samples were collected to measure stool quality, immunoglobulin A, and calprotectin, and blood samples were collected to measure serum chemistry, inflammatory markers, and hematology. On weeks 2 and 4, fresh fecal samples were collected to measure metabolites and microbiota. On week 4, total feces were collected to assess apparent total tract macronutrient digestibility. Although revertant numbers were greater compared with the solvent control in tester strain WP2uvrA(pKM101) in the presence of metabolic activation (S9) in the initial experiment, they remained below the threshold for a positive mutagenic response in follow-up confirmatory tests, supporting that GNU100 is not mutagenic. Similarly, no cytotoxicity or chromosome damage was observed in the cell micronucleus test. The palatability test showed that 1% GNU100 was strongly preferred (P < 0.05; 3.6:1 consumption ratio) over the control. In study 3, all dogs were healthy and had no signs of GI intolerance or illness. All diets were well accepted, and food intake, fecal characteristics, metabolite concentrations, and macronutrient digestibilities were not altered. GNU100 modulated fecal microbiota, increasing evenness and Catenibacterium, Megamonas, and Prevotella (SCFA producers) and reducing Collinsella. Overall, the results suggest that GNU100 is palatable and well-tolerated, causes no genotoxicity or adverse effects on health, and beneficially shifts the fecal microbiota, supporting the safety of GNU100 for the inclusion in canine diets.     

Determination of canine beta2-microgloblin in plasma and urine by enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay was developed for the determination of canine beta2-microglobulin (beta2-m) in plasma and urine. The detectable sensitivity for pure canine beta2-m was 0.05 microg/l and the analytical range was 0.1 to 50 microg/l. The mean analytical recovery when pure canine beta2-m was added to normal plasma was 101.9%. The mean analytical recovery in the urine was 102.1%. The intra-day variation coefficient was 3.1% in plasma, 4.3% in serum and 1.9% in urine. No difference was found between the concentration of beta2-m in plasma and serum (n=17). The concentration of beta2-m in the plasma of normal dogs was 1.82 +/- 0.57 mg/l (n=31). The mean excretion in 24 hr urine collected from normal dogs was 17.6 +/- 9.2 microg/l, 0.22 +/- 0.12 microg/kg of body weight or 14.2 +/- 9.4 microg/g of urine creatinine. The beta2-m creatinine index of random urine samples was 23.5 +/- 16.6 microg/g (n=26). There was a close correlation between the beta2-m creatinine index of 24 hr urine samples and that of random urine samples (r=0.872).     

Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets

The objectives of this study were to determine differences in apparent total tract energy and macronutrient digestibility, fecal and urine characteristics, and serum chemistry of domestic cats fed raw and cooked meat-based diets and extruded diet. Nine adult female domestic shorthair cats were utilized in a replicated 3 × 3 Latin square design. Dietary treatments included a high-protein extruded diet (EX; 57% CP), a raw beef-based diet (RB; 53% CP), and a cooked beef-based diet (CB; 52% CP). Cats were housed individually in metabolic cages and fed to maintain BW. The study consisted of three 21-d periods. Each period included diet adaptation during d 0 to 16; fecal and urine sample collections during d 17 to 20; and blood sample collection at d 21. Food intake was measured daily. Total feces and urine were collected for determination of nutrient digestibility. In addition, a fresh urine sample was collected from each cat for urinalysis, and a fresh fecal sample was collected from each cat for determination of DM percentage and ammonia, short-chain fatty acid (SCFA), and branched-chain fatty acid (BCFA) concentrations. All feces were scored after collection using a scale ranging from 1 (hard, dry pellets) to 5 (watery, liquid that can be poured). Blood was analyzed for serum metabolites. Apparent total tract DM, OM, CP, fat, and GE digestibilities were greater (P ≤ 0.05) in cats fed RB and CB than those fed EX. Total fecal SCFA concentrations did not differ among dietary treatments; however, molar ratios of SCFA were modified by diet, with cats fed RB and CB having an increased (P ≤ 0.05) proportion of fecal propionate and decreased (P ≤ 0.05) proportion of fecal butyrate compared with cats fed EX. Fecal concentrations of ammonia, isobutyrate, valerate, isovalerate, and total BCFA were greater (P ≤ 0.05) in cats fed EX compared with cats fed RB and CB. Our results indicated that cooking a raw meat diet does not alter apparent total tract energy and macronutrient digestibility and may also minimize risk of microbial contamination. Given the increasing popularity of feeding raw diets and the metabolic differences noted in this experiment, further research focused on the adequacy and safety of raw beef-based diets in domestic cats is justified.     

Water deprivation test in the dog: maximal normal values.

Studies were undertaken to determine maximal urine osmolality and urine specific gravity following water deprivation for 20 dogs with normal renal function. In addition, the reliability of body weight, skin pliability, total plasma protein concentration, and packed cell volume as indices of negative water balance was assessed. Following water deprivation for periods sufficient to induce dehydration, the mean maximal urine osmolality was 2,289 mOsm/kg. The corresponding mean maximal urine specific gravity was 1.062 and ranged from 1.050 to 1.076. The ratio of mean maximal urine osmolality to mean serum osmolality at the time of peak urine concentration was 7.3. There was no detectable difference in urine concentration indices between males and females. Changes in skin pliability and packed cell volume proved unreliable as estimates of dehydration. Weight loss and increases in total plasma protein concentration proved to be more consistent indicators of hydration status. Abnormal increases in serum urea nitrogen and serum creatinine concentrations occurred rarely, even though some dogs had water withheld for periods of up to 96 hours.     

Dietary chenodeoxycholic acid improves growth performance and intestinal health by altering serum metabolic profiles and gut bacteria in weaned piglets

Nutritional diarrhea and subsequent performance degradation in weaned piglets are major challenges for the pig industry. Bile acids (BA) can be added to the diet as emulsifiers. This experiment was conducted to investigate the effects of chenodeoxycholic acid (CDCA), a major primary BA, on growth performance, serum metabolic profiles and gut health in weaned piglets. A total of 72 healthy weaned piglets were randomly assigned to the control (CON) and the CDCA groups, which were feed a basal diet and the basal diet supplemented with 200 mg/kg CDCA for 30 d, respectively. Our results demonstrated that CDCA significantly increased final BW and average daily gain (ADG), decreased feed-to-gain (F:G) ratio and tended to reduce diarrhea incidence. In addition, CDCA increased the villus height-to-crypt depth (V:C) ratio, elevated goblet cell numbers and the expression of tight junction proteins, suggesting the enhancement of intestinal barrier function. As an emulsifier, CDCA increased jejunal lipase activity and the mRNA expression of pancreatic lipases. CDCA supplementation also altered the serum metabolic profiles, including increasing the levels of indole 3-acetic acid, N′-formylkynurenine and theobromine that were beneficial for gut health. Moreover, the relative abundance of 2 beneficial gut bacteria, Prevotella9 and PrevotellaceaeTCG-001, were increased, whereas the relative abundance of a harmful bacteria, Dorea, was decreased in the gut of weaned piglets supplemented with CDCA. Importantly, the altered serum metabolic profiles showed a strong correlation with the changed gut bacteria. In conclusion, CDCA improved the growth performance of weaned piglets by improving intestinal morphology and barrier function, and enhancing lipid digestion, accompanied by alterations of serum metabolic profiles, and changes in relative abundance of certain gut bacteria.     

Effects of dietary macronutrient profile on apparent total tract macronutrient digestibility and fecal microbiota,fermentative metabolites,and bile acids of female dogs after spay surgery

Obesity and estrogen reduction are known to affect the gut microbiota and gut microbial-derived metabolites in some species, but limited information is available in dogs. The aim of this study was to determine the effects of dietary macronutrient profile on apparent total tract macronutrient digestibility, fecal microbiota, and fecal metabolites of adult female dogs after spay surgery. Twenty-eight adult intact female beagles (age: 3.02 ± 0.71 yr, BW: 10.28 ± 0.77 kg; BCS: 4.98 ± 0.57) were used. After a 5-wk baseline phase (week 0), 24 dogs were spayed and randomly allotted to one of three experimental diets (n = 8 per group): 1) control (CO) containing moderate protein and fiber (COSP), 2) high-protein, high-fiber (HPHF), or 3) high-protein, high-fiber plus omega-3 and medium-chain fatty acids (HPHFO). Four dogs were sham-operated and fed CO (COSH). All dogs were fed to maintain BW for 12 wk after spay and then allowed to consume twice that amount for 12 wk. Fecal samples were collected at weeks 0, 12, and 24 for digestibility, microbiota, and metabolite analysis. All data were analyzed using repeated measures and linear mixed models procedure of SAS 9.4, with results reported as a change from baseline. Apparent organic matter and energy digestibilities had greater decreases in HPHF and HPHFO than COSH and COSP. Increases in fecal acetate, total short-chain fatty acids, and secondary bile acids were greater and decreases in primary bile acids were greater in HPHF and HPHFO. Principal coordinates analysis of weighted UniFrac distances revealed that HPHF and HPHFO clustered together and separated from COSH and COSP at weeks 12 and 24, with relative abundances of Faecalibacterium, Romboutsia, and Fusobacterium increasing to a greater extent and Catenibacterium, Bifidobacterium, Prevotella 9, Eubacterium, and Megamonas decreasing to a greater extent in HPHF or HPHFO. Our results suggest that high-protein, high-fiber diets alter nutrient and energy digestibilities, fecal metabolite concentrations, and fecal gut microbiota, but spay surgery had minor effects. Future research is needed to investigate how food intake, nutrient profile, and changes in hormone production influence gut microbiota and metabolites of dogs individually and how this knowledge may be used to manage spayed pets.     

Effect of acute induced metabolic alkalosis on the acid/base responses to sprint exercise of six racing greyhounds

To investigate the effect of acute induced metabolic alkalosis on the haematological, biochemical and metabolic responses to sprint exercise, six greyhound dogs with previously placed carotid artetrial catheters were raced four times over a distance of 400 metres. Each dog was raced twice after receiving oral sodium bicarbonate solution (NaHCO₃) (400 mg kg⁻¹) or lactated Ringer's solution ( ). Before, and for intervals of up to one hour after, the exercise arterial blood samples were collected for the measurement of blood gases, packed cell volume, total protein, serum biochemistry and plasma lactate. The time to complete the 400 metre sprint ranged from 32·7 seconds to 36·9 seconds. There was no significant difference in racing times between the dogs treated with NaHCO₃ and , and there was no significant difference between the plasma lactate measurements after the treatments with NaHCO₃ or . Serum chloride concentrations were significantly lower after NaHCO₃ than after LRS, and there was a trend towards a lower serum potassium concentration after NaHCO₃ treatment. Plasma lactate concentrations showed a similar increase and time course of disappearance after both LRS and NaHCO₃ treatments. There were significant changes in all the parameters measured after the exercise, but there were large variations between individual dogs and between races when the dogs were receiving the same treatment.     

Clinical evaluation of urinary liver-type fatty acid-binding protein for the diagnosis of renal diseases in dogs

Liver-type fatty acid-binding protein (L-FABP) is a biomarker for the early detection of renal diseases in humans. L-FABP is a cytotoxic oxidation product secreted from the proximal tubules under ischemic and oxidative stress conditions. First, L-FABP gene expression in the kidney and liver was evaluated. Next, the urinary L-FABP concentrations in dogs with or without renal diseases were measured using a novel enzyme-linked immunosorbent assay kit. Urinary L-FABP was normalized relative to urinary creatinine (uCre) concentrations (µg/g uCre). Finally, the relationships between urinary L-FABP and renal biomarkers used in canine medicine or serum alanine transaminase (ALT) as an indicator of liver damage were examined. Serum and urine samples from 94 client-owned dogs including 23 dogs with renal diseases and 71 dogs without renal diseases were used for analysis. Relative L-FABP gene expression was confirmed both in the liver and kidney. Dogs with renal diseases had a significantly higher urinary L-FABP than those without, and its predictive cutoff value was 26 µg/g uCre. Urinary L-FABP was significantly correlated with serum creatinine (r=0.4674, P<0.01), urea nitrogen (r=0.4907, P<0.01), urine specific gravity (r=−0.5100, P<0.01), and urine protein/creatinine ratio (r=0.7216, P<0.01), but not with serum ALT. Hence, dogs with a high urinary L-FABP value were more likely to have renal diseases.