Effect of size on electrolyte apparent absorption rates and fermentative activity in dogs

The objectives of the study were to assess overall electrolyte absorption capacity as well as fermentative activity in dogs varying in body size in order to verify whether these parameters can explain the poor faecal quality in large dogs. Four breeds of dogs were used: six Miniature Poodles (MP), six Standard Schnauzers (SS), six Giant Schnauzers (GS) and six Great Danes (GD). Net absorption rates of electrolytes were assessed by calculating the apparent digestibility of sodium and potassium and measuring their content in stool. Fermentative activity was calculated by measuring faecal concentrations of lactic acid and short-chain fatty acids. The results showed higher faecal concentrations of fermentation products and electrolytes as well as poorer digestibility of electrolytes in Giant Schnauzers and Great Danes. Strong positive correlations were found between these different parameters and stool quality (scores and moisture). Lower overall electrolyte absorption and higher fermentative activity could thus be factors capable of explaining poorer faecal quality in these two large dog breeds.     

Colonic permeability is higher in Great Danes compared with smaller breed-dogs

Fed the same dry diet, large dogs show poorer fecal quality than small ones. A high colonic permeability could explain a low water and electrolyte net balance leading to high fecal water content. This experiment was conducted to evaluate colonic permeability in dogs varying in body size and to determine whether colonic permeability is related to fecal sodium concentration and fecal quality. Four breeds of dogs were used: six Miniature Poodles (MP), six Standard Schnauzers (SS), six Giant Schnauzers (GS) and six Great Danes (GD). Colonic permeability was evaluated using the ratio of urinary lactulose to sucralose (L:S) after oral administration. Fecal sodium concentration was measured by flame photometry. The urinary L:S ratio was significantly lower in GD, indicating a higher colonic permeability, than in the three other breeds (0.35 ± 0.12 for GD and 0.51 ± 0.05 for MP). GD also presented the higher fecal sodium concentrations and the poorest fecal quality. The higher fecal sodium concentration observed in GD could be explained by the higher colonic permeability and both these variables could be important explanations for higher fecal moisture in large dogs.     

Influence of age and body size on orocecal transit time as assessed by use of the sulfasalazine method in healthy dogs

OBJECTIVE: To compare orocecal transit time (OCTT) as assessed by use of the sulfapyridine appearance time in plasma after oral administration of sulfasalazine in dogs of varying age and body size and determine whether OCTT correlates with fecal quality. ANIMALS: 6 Miniature Poodles (MP), 6 Standard Schnauzers (SS), 6 Giant Schnauzers (GS), and 6 Great Danes (GD). PROCEDURE: Determinations of OCTT were made at 12, 22, 36, and 60 weeks of age. Dogs were fed sulfasalazine mixed with a meal. Blood samples were then collected for 6 hours. The OCTT was the time from ingestion of the meal to detection of sulfapyridine in plasma. Fecal moisture content and consistency were recorded during the same periods. RESULTS: Mean OCTT decreased during growth of GS and GD dogs. No correlation was found between OCTT and fecal variables during growth in the 4 breeds. Effect of body size was observed at 12 and 22 weeks of age, with a longer OCTT in GS and GD than in MP and SS dogs. Similar OCTTs were observed at 36 and 60 weeks of age in all breeds, although GS and GD dogs had poorer fecal quality during those periods. CONCLUSIONS AND CLINICAL RELEVANCE: An effect of age on OCTT was observed only in large-breed dogs, with longer transit times in puppies (12 weeks old) than in adults (60 weeks old). Mean OCTT is not correlated with body size in adult dogs. No relationship was detected between OCTT and fecal variables in healthy dogs.     

Gastrointestinal transit of solid radiopaque markers in large and giant breed growing dogs

Observations on food tolerance in dogs have shown that some breeds, especially the giant breeds, have a greater digestive sensitivity. One of the consequences common in these breeds is a higher faecal water content and a poor faecal quality. This could be explained, at least in part, by limited digestive capacity and function in giant breed dogs. In this report, the gastric emptying that represents one parameter of the digestive function was studied in large and giant breed dogs during their growth. Six Great Danes (GD) and six Giant Schnauzers (GS) were fed small radiopaque markers mixed with a test diet at 12, 22 and 36 weeks of age. Abdominal radiographs were made every 30 min for a period of 4 h and then hourly until 12 h. At 12 weeks of age, the gastric emptying pattern was similar in both breeds. However, from 22 weeks of age, the gastric emptying of the GD was significantly more rapid than that of GS. The gastric emptying of small markers tended to slow down in growing dogs, especially in GS. A significant positive correlation between the gastric emptying time of 50% of markers and the body weight was found. These results show that GD have a lower gastric retention time of foods, which could lead to a poor digestion and an altered absorption of nutrients. These could explained why digestive function and sensitivity could be different in dogs from different sizes and breeds.     

Evaluation of association between body size and large intestinal transit time in healthy dogs

OBJECTIVE: To compare large intestinal transit time (LITT) in dogs of various body sizes and determine whether fecal quality was correlated with LITT. ANIMALS: 6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes. PROCEDURE: LITT was calculated as the difference between total (TTT) and orocecal transit time (OCTT). Minimum and mean OCTTs were determined by use of the sulfasalazine-sulfapyridine method. Minimum TTT was estimated by use of chromium and ferric oxide as color markers, and mean TTT was calculated from the recovery from feces of ingested colored plastic beads. Fecal moisture content was determined and fecal consistency was scored during the same period. RESULTS: Large-breed dogs had higher fecal moisture content and more watery fecal consistency. No association between body size and OCTT was detected, but there was a positive correlation between body size and mean TTT. Mean LITT increased significantly with body size, from 9.1 +/- 1.1 hours in Miniature Poodles to 39.4 +/- 1.6 hours for Giant Schnauzers. Significant correlations were detected among mean LITT, mean TTT, and fecal scores, whereas no correlation was observed between fecal moisture content and TTT or LITT. CONCLUSIONS AND CLINICAL RELEVANCE: LITT was correlated with fecal consistency in dogs of various body sizes. Mean LITT can be predicted from values for mean TTT in healthy dogs.     

Comparison of urine composition of healthy Labrador retrievers and miniature schnauzers.

OBJECTIVE: To compare urine composition in Labrador Retrievers (LR) and Miniature Schnauzers (MS) fed the same dog food. ANIMALS: 8 healthy LR (mean [+/- SD] age, 3.1+/-1.7 years) and 8 healthy MS (mean age, 3.7+/-1.3 years). PROCEDURE: A nutritionally complete dry dog food was fed to the dogs for 24 days. Urinary pH, volume, specific gravity, frequency of urination, and urinary concentrations of 12 analytes were measured for each dog; urinary relative supersaturation (RSS) with calcium oxalate and brushite (calcium hydrogen phosphate dihydrate) were calculated from these values. RESULTS: MS urinated significantly less often and had a lower urine volume (ml/kg of body weight per d) and a significantly higher urine pH, compared with LR. Urinary calcium concentration and brushite RSS were significantly higher in the urine of MS. As a result of a high calorie requirement, primarily as a result of high surface area to volume ratio, MS had significantly higher intake (per kg body weight) of dietary minerals, compared with LR. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in urine composition exist between breeds fed the same diet, some of which, including lower urine volume, higher calcium concentration, and higher brushite RSS, may contribute to the high prevalence of calcium oxalate uroliths observed in MS. Differences between breeds should be considered when evaluating strategies for controlling calcium oxalate stone formation.     

Influence of age and body size on gastrointestinal transit time of radiopaque markers in healthy dogs

OBJECTIVE: To compare gastric emptying time, small-intestinal transit time (SITT), and orocecal transit time (OCTT) of radiopaque markers in dogs varying in age and body size and to determine whether fecal variables (ie, consistency and moisture content) are related to gastrointestinal tract transit times in dogs. ANIMALS: 24 eight-week-old female puppies, including 6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes. PROCEDURE: Gastrointestinal tract transit time experiments were performed at 12, 22, 36, and 60 weeks of age. Dogs were fed 30 small radiopaque markers mixed with a meal. Abdominal radiographs were taken. The time at which 50% of the markers had left the stomach (T50) and the time at which the first marker reached the colon were calculated. Fecal moisture content and scoring on the basis of fecal consistency were recorded during the same periods. RESULTS: Puppies had a shorter mean T50 than adults, and mean OCTT decreased significantly only during growth of large-breed dogs. However mean fecal moisture content significantly increased with age, except in Giant Schnauzers. No effect of body size on T50 was found regardless of age, and no difference was observed between OCTT of small- and large-breed adult dogs. The effect of age on the mean SITT was not significant for any breed. However, a strong positive correlation was recorded between body size and fecal moisture content (r2 = 0.77) or fecal scores (r2 = 0.69) in adult dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Age affects T50 in small- and large-breed dogs and OCTT in large-breed dogs. However, body size does not affect T50 or OCTT. A relationship does not exist between gastrointestinal tract transit time and fecal variables in healthy dogs.     

Serum triglyceride concentrations in Miniature Schnauzers with and without a history of probable pancreatitis

Background: The association between hypertriglyceridemia and pancreatitis remains obscure in dogs. A possible role of hypertriglyceridemia as a cause of pancreatitis in Miniature Schnauzers has been suspected. Hypothesis/Objectives: To compare serum triglyceride concentrations between Miniature Schnauzers with and without a recent history of pancreatitis. Animals: Seventeen Miniature Schnauzers with a history of pancreatitis (group 1) and 34 age‐matched Miniature Schnauzers without a history of pancreatitis (group 2) were prospectively enrolled. Methods: Prospective case‐control study. Two samples were collected from each of the 17 Miniature Schnauzers with pancreatitis: 1 during pancreatitis and 1 after clinical and biochemical resolution of pancreatitis. Serum triglyceride and cholesterol concentrations were compared between group 1 (after resolution of pancreatitis) and group 2. Results: Miniature Schnauzers in group 1 were significantly more likely to have hypertriglyceridemia (>108 mg/dL) (71%) after resolution of pancreatitis than Miniature Schnauzers in group 2 (33%; odds ratio = 5.02; 95% confidence interval = 1.4–17.8; P= .0163). Serum triglyceride concentrations were significantly higher in dogs of group 1 (median: 605.0 mg/dL) after resolution of pancreatitis than in dogs of group 2 (median: 73.5 mg/dL; P= .002). Conclusions and Clinical Importance: Miniature Schnauzers with a history of pancreatitis were 5 times more likely to have hypertriglyceridemia than controls. Hypertriglyceridemia might be associated with the development of pancreatitis in some dogs of this breed. Additional studies are needed to further clarify the role of hypertriglyceridemia in the development of pancreatitis in Miniature Schnauzers as well as other dog breeds.     

Stomatocytosis in 7 related Standard Schnauzers

BACKGROUND: Hereditary canine stomatocytosis has been described in purebred Alaskan Malamutes, Drentse Patrijshonds, and Miniature Schnauzers. In humans, hereditary stomatocytosis is a heterogeneous group of congenital disorders characterized by the presence of stomatocytes in blood, increased osmotic fragility, and frequently, hemolytic anemia. OBJECTIVE: Our objective was to describe hematologic findings and RBC characteristics in 7 closely related Standard Schnauzers with stomatocytosis. METHODS: The following parameters were measured using an automated analyzer: HCT, RBC, hemoglobin (Hb) concentration, MCV, MCH, MCHC, red cell distribution width (RDW), WBC, platelet count, mean platelet volume (MPV), thrombocrit (PCT), and platelet distribution width (PDW). Differential leukocyte count, platelet estimate, reticulocyte count, and the percentage of stomatocytes in blood films were microscopically evaluated. An osmotic fragility test of RBCs and measurement of intracellular Na+, K+, and 2,3-diphosphoglycerate (2,3-DPG) concentrations were also performed. RESULTS: The affected dogs had macrocytosis (80.0 +/- 4.2 fL, reference interval 60-76 fL), decreased MCHC (29.3 +/- 0.8 g/dL, reference interval 32-39 g/dL), slightly increased RDW (17.3 +/- 0.4%, reference interval 12-16%), and an increased reticulocyte count (1.55 +/- 0.77%, reference interval <1%). The percentage of stomatocytes in blood films varied from 0.6 to 18.9% of all RBCs. Erythrocyte osmotic fragility and intracellular Na+ (138.1 +/- 3.2 mmol/L; controls 99 +/- 6.1 mmol/L), K+ (8.1 +/- 0.8 mmol/L; controls 6.1 +/- 0.5 mmol/L), and 2,3-DPG (21.9 +/- 2.0 micromol/g Hb; controls: 14.6 +/- 3.3 micromol/g Hb) concentrations were increased in dogs with stomatocytosis. CONCLUSIONS: Hematologic findings and the metabolic defects in RBCs in these Standard Schnauzers were consistent with a diagnosis of stomatocytosis. Parentage analysis suggests that stomatocytosis in Standard Schnauzers may have a hereditary component.     

Prevalence of calcium oxalate uroliths in miniature schnauzers.

Epidemiologic data were evaluated from all dogs admitted to the University of Minnesota, Veterinary Teaching Hospital (UMVTH) between June 1981 and November 1989. Of 69,890 admissions, 2,077 were Miniature Schnauzers. Uroliths were retrieved from 63 of the 2,077 Miniature Schnauzers admitted. In 20 of the 63 urolith episodes, calcium oxalate was the predominant mineral identified. By comparison, calcium oxalate uroliths were identified in only 56 of the remaining 67,813 non-Miniature Schnauzer canine admissions. The odds that uroliths from Miniature Schnauzers were composed of calcium oxalate was 11.8 times greater than for other canine breeds evaluated at the UMVTH (95% confidence interval = 6.8 to 20.1). Data also were evaluated from files of uroliths retrieved from dogs and submitted to the Minnesota Urolith Center for quantitative mineral analysis, between June 1981 and November 1989. Of 3,930 uroliths analyzed, 615 (15.6%) uroliths were obtained from Miniature Schnauzers. of the 615 uroliths, 175 (28.4%) were calcium oxalate. By comparison, only 550 (16.6%) of the remaining 3,315 from dogs of breeds other than Miniature Schnauzers were calcium oxalate. The odds that uroliths submitted for analysis were composed of calcium oxalate was 2 times greater for Miniature Schnauzers than for dogs of other breeds (95% confidence interval = 1.6 to 2.4). Calcium oxalate uroliths were retrieved more frequently in males than females. The risk for males developing calcium oxalate uroliths was greater than 3 times the risk for females in both groups of data evaluated. The mean age of all Miniature Schnauzers admitted to the UMVTH with calcium oxalate uroliths was 9 years. Calcium oxalate uroliths were not detected in Miniature Schnauzers younger than 1.7 years.     

Evaluation of low-ash poultry meal as a protein source in canine foods

Eight mature female dogs (18.0 +/- 0.2 kg) were used in a replicated 4 x 4 Latin square experiment to determine the feeding value of low-ash poultry meal (PM) in a complete food fed to dogs. All foods contained graded concentrations of PM (10.4 to 32.5% DM), resulting in foods that were 10, 15, 20, and 25% CP. Daily DMI averaged 284 +/- 14 g/d. An increase in PM resulted in an increase in fecal moisture from 44.7 to 55.1% (linear; P < 0.01), and fecal DM output increased from 24.8 to 31.6 g/d (linear; P < 0.05). Ileal DM flow increased from 27.1 to 40.7 g/d (linear; P < 0.01). Small intestinal DM digestibility decreased from 90.4 to 86.1% (linear; P < 0.01) and total-tract DM digestibility decreased from 91.2 to 89.4% (linear; P < 0.01) as PM increased. Large intestinal DM digestibility increased from 8.4 to 21.1% with increasing PM (linear; P < 0.05). Fecal excretion of CP increased from 5.6 to 10.0 g/d (linear; P < 0.01) and ileal flow of CP increased from 6.9 to 15.6 g/d (linear; P < 0.01) as PM increased. Small intestinal CP digestibility was unaffected with treatment (P > 0.05). Large intestinal CP digestibility increased from 21.6 to 37.1% (linear; P < 0.05) with increasing PM. Total-tract CP digestibility increased from 81.0 to 86.6% (linear; P < 0.01) as PM increased. Arginine had the highest overall digestibility ranging from 88.5 to 91.3%, whereas cysteine had the lowest digestibility, ranging from 67.1 to 71.4%. These data indicate that PM is a highly digestible protein source for canine foods with inclusions of 10.4 to 32.5% of DM.     

Influence of age and body size on intestinal permeability and absorption in healthy dogs

OBJECTIVE: To evaluate effects of age and body size of dogs on intestinal permeability (unmediated diffusion) as measured by the ratio of urinary lactulose to L-rhamnose (L:R) and absorption (carrier-mediated transport) as measured by the ratio of urinary D-xylose to 3-O-methyl-D-glucose (X:MG) and to determine whether these variables correlated with fecal quality. ANIMALS: 6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes. PROCEDURE: A solution that contained lactulose and rhamnose or xylose and 3-O-methyl-D-glucose was administered orally to dogs that were 12, 22, 36, and 60 weeks old. Urine was collected 6 hours later, and urinary L:R and X:MG were calculated. Fecal moisture and scoring were recorded during the same periods. RESULTS: Age and breed did not affect intestinal absorption, and we did not detect a relationship between X:MG and fecal variables. In contrast, we detected significant effects of age and body size on intestinal permeability. Puppies (12 weeks old) and large dogs had higher intestinal permeability than adult (60 weeks old) and small dogs. The increased intestinal permeability in large dogs was associated with lower fecal quality as indicated by the significant positive correlations between L:R and fecal moisture (r, 0.61) and L:R and fecal scores (r, 0.86) in adult dogs. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicate that age and body size should be considered when assessing intestinal permeability by use of the L:R urinary excretion test in dogs. High intestinal permeability could be a possible cause of poor fecal quality in large dogs.     

Effect of dietary moisture and sodium content on urine composition and calcium oxalate relative supersaturation in healthy miniature schnauzers and labrador retrievers

The aim of this series of studies was to evaluate two possible feeding strategies as methods for reducing the risk of calcium oxalate (CaOx) formation in two breeds of healthy dog. The studies compared the effect of dietary moisture (Study 1) and dietary sodium (Na), (Study 2) on urine composition of labrador retrievers (LR) and miniature schnauzers (MS). A nutritionally complete dry dog food was fed to 16 dogs (eight LR, eight MS; Study 1) and 15 dogs (seven LR, eight MS; Study 2) for 24 days (Study 1), or 36 days (Study 2). The dogs were fed the diet alone (7% moisture, 0.06 g Na/100 kcal), or supplemented with deionised water to 73% moisture (Study 1), or dietary Na, to deliver 0.20 or 0.30 g Na per 100 kcal (Study 2). Urine pH, volume, specific gravity, and concentrations of 12 analytes were measured for each dog. Urinary relative supersaturations (RSS) with CaOx were calculated from these values. The effects of supplemental Na or water were established using t tests (Study 1) or analysis of variance, and multiple range tests (least significant difference) (Study 2); P<0.05 was considered significant. Increasing dietary moisture significantly increased total moisture intake (P=0.001), and reduced urine specific gravity (P=0.003), urinary oxalate concentration (P=0.04), and CaOx relative supersaturation (P=0.04) in the MS. Urinary parameters remained unchanged in the LR, indicating that feeding a high moisture diet may reduce the risk of CaOx formation in high-risk breeds. Increasing dietary Na led to production of urine with a significantly lower CaOx RSS in both breeds, indicating that sodium supplementation to dry diet formats may reduce the risk of CaOx formation. These feeding strategies should be considered when evaluating methods for preventing CaOx formation within high-risk groups.     

Investigation of hypertriglyceridemia in healthy Miniature Schnauzers

BACKGROUND: Idiopathic hypertriglyceridemia has been reported in Miniature Schnauzers (MS). However, studies investigating the prevalence of this disorder in a large population of MS are lacking. HYPOTHESIS: Hypertriglyceridemia is prevalent in healthy MS. ANIMALS: This study used 192 healthy MS and 38 healthy dogs of other breeds (control dogs). METHODS: Serum triglyceride and cholesterol concentrations were measured and statistically compared in both the MS and control group. Dogs were categorized based on their age, and median serum triglyceride concentrations were compared among different age groups. RESULTS: A total of 63 (32.8%) of the 192 MS had serum triglyceride concentrations above the reference range. In contrast, of the 38 control dogs, only 2 (5.3%) had serum triglyceride concentrations above the reference range. The median serum triglyceride concentration in MS was 73.5 mg/dL, which was significantly higher as compared to that of the control group (median, 55 mg/dL; P = .0005). Serum cholesterol concentration was above the reference range in 9 (9.0%) of 100 MS and in 2 (5.3%) of the control dogs. Mean serum cholesterol concentrations were not significantly different between the 2 groups (P = .1374). Median serum triglyceride concentrations in MS increased significantly with age (P < .0001), and there was a significant positive correlation between serum triglyceride concentrations and age (Spearman r = 0.47; P < .0001). There was no difference in serum triglyceride concentrations between male and female MS (P = .48). CONCLUSION: Healthy MS have a high prevalence of hypertriglyceridemia as compared to healthy dogs of other breeds. Both the prevalence and severity of hypertriglyceridemia increase with age.     

Digestion studies in captive Hippopotamidae: a group of large ungulates with an unusually low metabolic rate

We performed intake and digestibility studies in four common (Hippopotamus amphibius) and four pygmy (Hexaprotodon liberiensis) hippos from two zoological institutions, using acid detergent lignin as an internal marker for the quantification of faecal output. In the case of one pygmy hippo, where total faecal collection was also possible, there was no distinct difference between the two methods of faecal output quantification. Two animals from each species were tested on a conventional zoo diet of hay and concentrates (diet HC) and on hay only (diet H). The other two animals received fresh grass at two different levels of intake (diets G1 and G2). Dry matter (DM) intake was higher on HC than on H or G diets, and averaged 37 +/- 11 for common and 35 +/- 14 g/kg(0.75) for pygmy hippos. There were no species differences in the average digestibility (aD) coefficients. Non-dietary faecal nitrogen averaged 65 +/- 4% of total faecal nitrogen, aD of crude protein (CP) averaged 67 +/- 9% and true protein digestibility 89 +/- 3%. Average digestibility of DM and crude fibre averaged 54 +/- 11% and 45 +/- 17%, respectively. In comparison with ruminants, hippos generally achieve lower aD for DM, organic matter and fibre parameters, but equal or higher aD CP coefficients. This is most likely due to the absence of significant fermentative activity in the hindgut and the corresponding low metabolic faecal nitrogen losses. Digestible energy intake was higher on HC than on H or G diets and averaged 0.30 +/- 0.11 MJ/kg(0.75) metabolic body mass. This value is extremely low for ungulates, supporting earlier suspicions that hippos have particularly low metabolic rates, and explains the proneness of this species to obesity in captivity when fed energy-dense pelleted feeds.     

Effects of epidural administration of dexmedetomidine on the minimum alveolar concentration of isoflurane in dogs

Objective-To evaluate the effects of epidural administration of 3 doses of dexmedetomidine on isoflurane minimum alveolar concentration (MAC) and characterize changes in bispectral index (BIS) induced by nociceptive stimulation used for MAC determination in dogs. Animals-6 adult dogs. Procedures-Isoflurane-anesthetized dogs received physiologic saline (0.9% NaCl) solution (control treatment) or dexmedetomidine (1.5 [DEX1.5], 3.0 [DEX3], or 6.0 [DEX6] mug/kg) epidurally in a crossover study. Isoflurane MAC (determined by use of electrical nociceptive stimulation of the hind limb) was targeted to be accomplished at 2 and 4.5 hours. Changes in BIS attributable to nociceptive stimulation and cardiopulmonary data were recorded at each MAC determination. Results-With the control treatment, mean +/- SD MAC values did not change over time (1.57 +/- 0.23% and 1.55 +/- 0.25% at 2 and 4.5 hours, respectively). Compared with the control treatment, MAC was significantly lower at 2 hours (13% reduction) but not at 4.5 hours (7% reduction) in DEX1.5-treated dogs and significantly lower at 2 hours (29% reduction) and 4.5 hours (13% reduction) in DEX3-treated dogs. The DEX6 treatment yielded the greatest MAC reduction (31% and 22% at 2 and 4.5 hours, respectively). During all treatments, noxious stimulation increased BIS; but changes in BIS were correlated with increases in electromyographic activity. Conclusions and Clinical Relevance-In dogs, epidural administration of dexmedetomidine resulted in dose-dependent decreases in isoflurane MAC and that effect decreased over time. Changes in BIS during MAC determinations may not represent increased awareness because of the possible interference of electromyographic activity.     

Correlation of age and incidence of pancreatic exocrine nodular hyperplasia in the dog

The purpose of this study was to determine the prevalence of pancreatic nodular hyperplasia (NH) and its relation to age in the dog. A total of 101 dogs were enrolled. The pancreas was evaluated by histology and hyperplastic lesions were detected and scored. Age was recorded from the medical records. Correlation of age with inflammation and presence of hyperplastic lesions was evaluated. Of the 101 dogs, 81 (80.2%) had evidence of NH. Twenty-five of the 101 dogs did not have evidence of pancreatic inflammation, necrosis, and/or fibrosis, 17 (68.0%) of which had evidence of NH. Mean +/- SD age in dogs with NH was significantly higher compared with dogs without NH (9.5 +/- 3.4 years versus 3.4 +/- 3.3; P-value < 0.0001). We conclude that NH is a common pathologic lesion in dogs and shows a positive correlation with age regardless of the presence or absence of pancreatic inflammation, necrosis, or fibrosis.     

Use of pulmonary hydrogen gas excretion to detect carbohydrate malabsorption in dogs

Pulmonary H2 excretion was measured in 10 healthy dogs, in 6 dogs with pancreatic exocrine insufficiency, and in 6 dogs with chronic small intestinal disease. Concentration of expired H2 in fasted healthy dogs was 0.9 +/- 0.1 ppm (mean +/- SEM) and peak H2 concentration of 1.4 +/- 0.2 ppm was detected up to 8 hours after feeding. Dogs with pancreatic exocrine insufficiency had fasting expired H2 concentrations of 3.3 +/- 0.9 ppm, which increased to a mean peak H2 concentration of 28.8 +/- 2.0 ppm 6.5 hours after feeding. Following xylose administration, expired H2 concentrations increased from fasting concentrations of 3.6 +/- 0.9 ppm to peak at 19.0 +/- 2.0 ppm in 1.5 hours. Blood xylose concentrations were diagnostic for carbohydrate malabsorption in 4 of 6 dogs with pancreatic exocrine insufficiency. Plasma p-aminobenzoic acid concentration identified bentiromide maldigestion in all dogs with pancreatic exocrine insufficiency. In 3 pancreatic exocrine insufficient dogs tested, pancreatic enzyme replacement therapy partially corrected carbohydrate malabsorption. Fasting expired H2 concentration was 5.3 +/- 1.3 ppm in dogs with chronic small intestinal disease and increased to a peak H2 of 72.2 +/- 18.0 ppm 7 hours after feeding. Following administration of xylose to dogs with chronic small intestinal disease, fasting expired H2 concentration increased from 3.0 +/- 1.0 ppm to a peak of 35.5 +/- 7.2 ppm at 2 hours. Blood xylose concentration was abnormal in only 2 of 6 dogs with chronic small intestinal disease. Results of these studies indicate that expired H2 analysis can identify carbohydrate malabsorption in dogs with pancreatic exocrine insufficiency or chronic small intestinal disease, and that pulmonary H2 testing is more sensitive than xylose absorption testing for the identification of carbohydrate malabsorption.     

Fibre analysis and fibre digestibility in pet foods--a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre

Six dry dog foods and six dry cat foods with different carbohydrate sources were investigated in digestion trials. Food and faecal samples were analysed for CF, TDF and starch. In dogs, also neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom) were analysed. N-free extract (NfE) was calculated for CF, and similarly for all other fibre analyses. Linear regressions were calculated between fibre intake and faecal fibre excretion. True digestibility was calculated from the regression coefficients [true digestibility in % = (1 - regression coefficient)*100], with the intercept of the equation representing excretion of material of non-food origin. Crude fibre analyses gave the lowest values, and TDF the highest, while ADFom and aNDFom were in between. Variation between diets was lowest in CF and highest in TDF. Total dietary fibre, aNDFom and ADFom in food were positively correlated. Crude fibre in food did not correlate with any other method. The NfE analogue for TDF was closest to the starch content. Methods of fibre analyses in faeces did not agree very well with each other. Crude fibre had the lowest apparent digestibility, followed by ADFom, TDF and aNDFom. For all fibre analyses, there was a significant correlation between fibre intake and faecal fibre excretion. True digestibility was close to zero for CF, with a high uniformity in both species. In dogs, true digestibility of aNDFom was 53%, of ADFom 26% and of TDF 37%; in cats, true digestibility of TDF was 31%. Except for CF, the intercept of the regression equations suggest that faecal excretion of some material of non-food origin is analysed as fibre. A combination of TDF and CF analyses might give good information on the content of total (TDF), unfermentable (CF) and partially fermentable fibre (TDF-CF) in pet foods.     

Ultracentrifugal and Electrophoretic Characteristics of the Plasma Lipoproteins of Miniature Schnauzer Dogs With Idiopathic Hyperlipoproteinemia

To better characterize the idiopathic hyperlipoproteinemia of Miniature Schnauzer dogs, the plasma lipoproteins of 20 Miniature Schnauzers (MS) and 11 dogs of other breeds (DOB) were evaluated by ultracentrifugation, electrophoresis, and biochemical tests. Seventeen MS were healthy; 3 had diabetes mellitus. Plasma from 6 of 17 healthy and all 3 diabetic MS was visibly lipemic. Lipemia was slight to marked in healthy lipemic MS, and marked in diabetic ones. All DOB had clear plasma; 8 were healthy and 3 had diabetes. All healthy lipemic MS and diabetic lipemic MS had hypertriglyceridemia associated with excess very low density lipoproteins. Chylomicronemia was present in 4 of 6 healthy lipemic MS and all 3 diabetic lipemic MS. Lipoproteins with ultracentrifugal and electrophoretic characteristics of normal low density lipoprotein were lacking in 4 of 6 healthy lipemic MS. The lipoprotein patterns of 4 of 11 healthy nonlipemic MS were characterized by mild hypertriglyceridemia associated with increased very low density lipoproteins and a lack of lipoproteins with characteristics of normal low density lipoproteins. Lipoprotein patterns of diabetic DOB closely resembled those of healthy DOB; those of diabetic lipemic MS resembled those of markedly lipemic healthy lipemic MS. In conclusion, the hyperlipoproteinemia of Miniature Schnauzers is characterized by increased very low density lipoproteins with or without accompanying chylomicronemia; some affected dogs may have decreased low density lipoproteins. (Journal of Veterinary Internal Medicine 1993; 7:253–260. Copyright © 1993 by the American College of Veterinary Internal Medicine.)