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1.
OBJECTIVE: To evaluate the effects of a high-protein diet versus dietary supplementation with ammonium chloride (NH4Cl) on struvite crystal formation in the urine of clinically normal cats by measuring the urine concentration of hydrochloric acid (HCl)-insoluble sediment, urine pH, struvite activity product (SAP), number of struvite crystals in urine, and urine volume. ANIMALS: 23 healthy adult cats. PROCEDURE: Urine was fractionated by centrifugation with subsequent extraction of the sediment with 1 N HCl (study 1). Diets containing either 29% crude protein or 55% crude protein were fed to cats in a crossover trial of 3 weeks/period (study 2). Diets supplemented with either sodium chloride (NaCl) or NH4Cl were fed, by use of a 3 x 3 Latin-square design with 3 wk/period (study 3). In studies 2 and 3, urine samples were collected for the last 7 days of each period. RESULTS: The HCl-insoluble sediment contained Tamm-Horsfall glycoprotein (THP; study 1). The high-protein diet (study 2) and dietary supplementation with NH4Cl (study 3) resulted in a decrease in urine pH, SAP, and the number of struvite crystals in urine. However, the high-protein diet decreased urine concentrations of HCl-insoluble sediment containing THP (study 2), in contrast to the NH4Cl supplementation that increased urine volume without a significant effect on the urine concentration of the HCl-insoluble sediment (study 3). CONCLUSIONS AND CLINICAL RELEVANCE: Our results indicate that compared with dietary supplementation with NH4Cl, the high-protein diet is preferable as a urine acidifier for the prevention of struvite crystal formation in clinically normal cats.  相似文献   

2.
In three separate experiments nine male cats were fed either a canned complete diet or a commercially available dry pelleted diet or the same dry diet containing 1.6 per cent ammonium chloride for seven days and then fasted for 20 hours. Then ad libitum feeding was continued and urine samples were taken at four-hour intervals for 12 hours and a final sample 12 hours later. Urine pH and the presence of struvite crystals in urine sediment were evaluated. The food and water intake of four of the nine cats was measured at the time of urine collection. After the fast, urine pH was raised, even after feeding the dry diet supplemented with ammonium chloride. A post prandial rise in urine pH was also seen on all three diets. After feeding the dry diet the postprandial peak pH was 7.97 and struvite occurred spontaneously. Urine pH after feeding the dry diet supplemented with ammonium chloride peaked at 7.75 then fell to 6.1 12 hours after the start of feeding. Struvite occurred spontaneously at all times until the pH reached 6.1 but when the pH of urine was raised to 7.0 the struvite crystallised. Urine pH on the canned complete diet peaked at 6.8 then fell to 5.8; struvite did not occur spontaneously but when urine pH was raised to 7.0 struvite crystallised except at the eighth and 12th hour sampling. These data show that fasting initiates a post prandial rise in urine pH and struvite crystalluria even when a normally effective urinary acidifier is used.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
To compare the effects of two dietary protein sources, fish meal (FM) and corn gluten meal (CGM), fecal moisture content, nitrogen balance and urinary excretion were examined in adult cats. The dietary protein source did not cause a significant difference in daily food intake, water intake, urine volume, dry matter digestibility or urinary nitrogen excretion, but fecal moisture content was lower (P<0.02) in the CGM group. The HCl-insoluble fraction of urinary sediment tended to be higher in the CGM group (P<0.10), although urinary pH was similar in the two groups. These results suggest that CGM is comparable with FM in respect to nutritional value and the urine acidifying effect, but FM may be preferable to CGM for the prevention of constipation and struvite urolithiasis in cats.  相似文献   

4.
The efficacy of a diet designed to facilitate dissolution of feline magnesium ammonium phosphate (struvite) uroliths was evaluated in 30 cases of urolithiasis, sterile struvite uroliths dissolved in a mean of 36 days after initiation of dietary treatment. In 5 cases of urolithiasis, struvite urocystoliths associated with urease-negative bacterial urinary tract infection dissolved in a mean of 23 days after initiation of dietary and antimicrobial treatment. In 3 cases of urolithiasis, struvite urocystoliths associated with urease-positive staphylococcal urinary tract infection dissolved in a mean of 79 days after initiation of dietary and antimicrobial treatment. Dissolution of uroliths in cats fed the treatment diet was associated with concomitant remission of dysuria, hematuria, and pyuria, and reduction in urine pH and struvite crystalluria. In one case, a urocystolith composed of 100% ammonium urate, and in another case, a urolith composed of 60% calcium phosphate, 20% calcium oxalate, and 20% magnesium ammonium phosphate did not dissolve.  相似文献   

5.
A large radiodense calculus in the left renal pelvis of a 22-month-old, male Great Dane disappeared one month following surgical removal of two struvite (magnesium ammonium phosphate) calculi from the right renal pelvis. The dog's urine likely became undersaturated with struvite for a sufficient period to permit dissolution of the renal calculus. Several factors may have contributed to the decrease in urine struvite concentration, including eradication of a urease-producing Proteus sp from the urinary tract and induction of polydipsia and compensatory polyuria by oral administration of sodium chloride.  相似文献   

6.
The chemical composition and microstructure of seven uroliths and four urinary sediment samples associated with the feeding of high-level cottonseed meal diet to buffalo calves were examined by chemical qualitative analyses, scanning electron microscopy ( ), X-ray diffraction, and X-ray energy dispersive spectrometry ( ). Struvite was a major component of kidney stones and of some bladder stones. The kidney stone sample appeared cracked under low power under , aggregated into tiny balls under high power, and as a bladelike structure under even higher power. The bladder stone samples appeared finely granular or granular with various forms of prismatic crystals. The urinary sediments were prismatic crystals, with granules. The newly found prismatic crystals, which were rich in potassium and similar to struvite in crystal structure, were identified as potassium magnesium phosphate (KMgPO4 · 6H2O) in some bladder stones and urinary sediments. However, crystals which contained Mg and P only, which had been used for struvite identification, were not found by examination in urinary sediments from fresh urine samples of buffalo calves fed the high-level cottonseed meal diet.  相似文献   

7.
Aggregates of struvite crystals caused urethral obstruction in a high percentage of cats fed moist and dry diets supplemented with Mg oxide. Some of the diets were associated with cystolith formation as well. The percentage of Mg in the experimental diets was a misleading indicator of Mg intake because of differences between moist and dry diets in their caloric density. Magnesium homeostasis was maintained in cats ingesting large quantities of Mg. Tissue (kidney, muscle, and rib) concentrations of Mg were the same in cats fed high Mg and control diets. Plasma Mg concentration was increased only in cats ingesting the largest amount of Mg. Magnesium homeostasis was maintained by a marked increase in urine Mg excretion. However, urine Mg concentration was not directly related to Mg intake, apparently because of differences between diets in intestinal absorption of Mg. Urethral obstruction of experimental cats was not associated with a transient increase in Mg intake, nor did obstructing cats have higher urine Mg concentrations than did nonobstructing cats fed the same diet. This observation indicates that factor(s) other than urine Mg concentration are important in urethral obstruction. Cats with urethral obstruction due to naturally occurring disease, feline urological syndrome (FUS), had markedly lower urine Mg concentrations than cats fed high Mg diets. This finding refutes the theory that cats develop FUS because of primary Mg hyperabsorptive phenomena or because of a primary urinary leak of Mg. It also indicates that factors other than urine Mg concentration are involved in the genesis of naturally occurring urethral obstruction. Another difference between the natural and the induced disease was related to the character of the urinary precipitates. Experimental diets higher in Mg concentration caused urolith formation, which is uncommon with FUS. Lower Mg diets caused obstruction with aggregates of crystals, but mucus was not observed. However, in the experimental disease induced in the present study, urinary precipitates were predominantly or exclusively struvite, as has been reported in the natural disease. Many similarities were seen between the diet-induced disease and FUS, but factors in addition to Mg intake are involved in the natural disease. The importance of Mg, compared with the undefined factors, remains to be established.  相似文献   

8.
Eighteen male cats were fed either a canned complete diet or a commercially available dry pelleted diet or the same dry diet containing 1.6 per cent ammonium chloride. The daily food and water intake of four of these cats was measured. Urine samples were taken at random and the pH and the presence of struvite crystals in their sediment estimated. In some samples in which the pH was less than 7.0, and struvite crystals were absent, the pH was increased to 7.0 and any sediment was examined for struvite. No spontaneous struvite was seen in urine samples (pH 5.8) from cats fed the canned complete diet but when its pH was raised to 7.0, 46 per cent of these samples showed struvite. Cats fed the dry pelleted diet had urine of higher pH (7.55) and 78 per cent of the samples contained struvite crystals. Cats fed this diet supplemented with ammonium chloride had a urine pH of 5.97 and only 9 per cent contained struvite crystals but when the pH was adjusted to 7.0 all the samples showed struvite crystals. Energy intake was similar on all three diets but the intake of dry matter was greater on the dry diets. Liquid water intake was greater on the dry diets but total water intake was greatest on the canned complete diet. The intake of magnesium, calcium and phosphate was greater on the dry diets. It is concluded that urine pH is a more important controller of struvite precipitation than mineral intake.  相似文献   

9.
OBJECTIVE: To compare the nutritional value of corn gluten meal (CGM) and meat meal (MM) as a dietary source of protein in dry food formulated for adult cats. ANIMALS: 8 healthy adult cats (4 males and 4 females). PROCEDURE: Diets containing CGM or MM as the main protein source were each fed for a 3-week period in a crossover study. Digestibility and nutritional balance experiments were conducted during the last 7 days of each period. Furthermore, freshly voided urine was obtained to measure urinary pH, struvite crystals, and sediment concentrations. RESULTS: Daily food intake and dry-matter digestibility were significantly higher for the MM diet. Fecal moisture content also was higher for the MM diet. Apparent nitrogen (N) absorption and N retention were higher for the MM diet, even when values were expressed as a percentage to account for differences in N intake. Urinary pH, struvite activity product, number of struvite crystals in urine, and urinary sediment concentrations were not different between diets. Retention of calcium, phosphorus, and magnesium was lower for the CGM diet, and cats lost body calcium and magnesium when fed the CGM diet. CONCLUSIONS AND CLINICAL RELEVANCE: Meat meal was superior to CGM as a protein source in dry foods formulated for cats, because dry-matter digestibility and N utilization were higher for the MM diet. In addition, net loss of body calcium and magnesium for the CGM diet suggests that mineral requirements increase when CGM is used as a protein source.  相似文献   

10.
There is an apparent reciprocal relationship between magnesium ammonium phosphate (MAP, struvite) and calcium oxalate (CaOx) urolithiasis incidence rate in cats. The number of struvite uroliths submitted for analysis over the past 35 years has been decreasing, with an increase in CaOx urolith submissions. Commercial diets aimed to dissolve struvite uroliths are typically acidified, and it has been suggested that dietary acidification increases urinary calcium excretion and the risk of CaOx crystallization. The objective of this study was to assess the effect of urine acidification on the relative supersaturation (RSS) of CaOx in cats, as a representation of crystallization risk. Four diets were extruded to contain identical nutrient contents, but with gradual acidification (0, 0.6, 1.3 and 1.9% sodium bisulphate substituted sodium chloride in diets A, B, C and D respectively). Thirteen adult cats were fed each diet sequentially for a minimum of 10 days. Average urine pH was 6.4, 6.2, 6.0 and 5.9 on diets A, B, C and D respectively (p < 0.0001). Struvite RSS decreased on diets inducing more acidic urine pH (p < 0.0001). Urinary calcium excretion and concentration increased with diets inducing lower urine pH (p < 0.0001), but oxalate excretion and concentration decreased (p < 0.001). CaOx RSS was not different between diets (p = 0.63). These results suggest that a lower diet base excess and resulting urine pH to support struvite dissolution do not increase the risk for CaOx crystallization in the range of urine pH representative of most commercial feline diets. Long-term studies are needed to confirm this.  相似文献   

11.
Ninety adult cats were fed an experimental canned meat-based cat food at levels necessary to maintain weight for 11 days. On the 12th day the cats were split into six groups of 15 cats each and fed 0, 20, 40, 60, 80 or 100 per cent of their previous food allotment. Four hours after the food was offered a urine sample was obtained via cysto-centesis. The pH of the urine sample was determined and the sample microscopically evaluated for the presence of struvite crystals. Post prandial urine pH was found to be a linear function of the amount of food consumed: (urine pH = 6–15 + [food intake (g) × 0–015]; P = 0-000). The presence of struvite crystals was dependent on urine pH while amorphous crystals were not. These data suggest that ad libitum feeding (nibble eating) may be beneficial in the management of feline struvite urolithiasis by reducing the magnitude of the post prandial alkaline tide. It also supports the suggestion that struvite crystal formation is largely a function of urinary pH.  相似文献   

12.
Twenty-four Quarter Horse weanlings (120 ± 10 d) were blocked by age into 4 groups (n=6) for a 56-d trial to evaluate the influence of dietary Met concentration on growth and N balance. Weanling horses were housed by block and individually fed concentrates twice daily at 1.75% BW (as-fed basis). Weanling horses were randomly assigned to 1 of 4 concentrate treatments: basal (0.20 Met), basal + 0.03% Met (0.23 Met), basal + 0.07% Met (0.27 Met), and basal + 0.11% Met (0.31 Met). Diets were formulated to be isonitrogenous and isocaloric and contained equal amounts of Lys and Thr. Coastal bermudagrass hay (Cynodon dactylon) was individually fed at 0.75% BW (as-fed basis). Growth measurements, BW, rump fat, and plasma were obtained every 7 d. The final 4 d consisted of total collection of urine and feces. Feed, fecal, and urine samples were analyzed for N content, and N balance was calculated. Urine was analyzed for urea and ammonia concentrations. Plasma was analyzed for urea concentration. Grain, hay, and fecal samples were analyzed for nutrient composition. Data were analyzed using the PROC MIXED procedure of SAS. Linear, quadratic, and cubic effects were tested in the form of contrasts. There was no influence (P>0.25) of treatment on growth measurements, N balance, or urinary urea or ammonia. Intake of Lys and Thr did not differ (P>0.08) among treatments. Methionine intake increased as expected with increasing Met inclusion in the diet (P<0.01). Plasma urea N responded quadratically (P=0.04) to treatment. An unexpected peak in PUN was observed with 0.27 Met. The results indicate future studies that can ensure Met as the only dietary variable are necessary to better explain the Met requirements of weanling horses.  相似文献   

13.
One hundred fifty specimens of urinary calculi from 150 cats were analyzed by at least 1 of 4 quantitative methods. Struvite (magnesium ammonium phosphate) was the predominant mineral substance encountered, with 104 (69%) of the calculi being composed entirely of struvite and 23 (15%) being composed partially of struvite. Most (93%) of the calculi were located in the urinary bladder. Growth of bacteria was observed in samples from calculi or urine from 30 (41%) of 74 cats. Coagulase-positive staphylococci were isolated from the urine or calculi from 17 cats (45% of bacteria isolated). Ten other bacterial species were isolated. Median and mean ages of the cats were 5.0 and 5.1 years, respectively. Domestic short-hair and domestic longhair breeds predominated. Fifty-seven percent of the calculi came from females, 43% from males. The distribution by gender did not differ significantly (P greater than 0.2) among the 3 groups (domestic shorthair, domestic longhair, and other). However, the distribution of struvite calculi differed significantly (chi 2 = 15.5, P less than 0.001) by age and gender; among cats less than or equal to 2 years of age, males predominated 2:1 over females, and among cats greater than 2 years of age, females predominated by nearly 3:1 over males. When compared with the general population, females greater than 2 years old were significantly (chi 2 = 15.4, P less than 0.001) overrepresented.  相似文献   

14.
OBJECTIVE: To evaluate effects of dietary carbohydrate on urine volume; struvite crystal formation; and calcium, phosphorus, and magnesium balance in clinically normal cats. ANIMALS: 21 healthy adult cats (15 sexually intact males and 6 sexually intact females). PROCEDURE: Diets containing no carbohydrate source (control diet), control plus starch, or control plus fiber were given in a 3 X 3 Latin-square design. The diets were available ad libitum in study 1 (n = 12) and given under restrictions in study 2 (9) to equalize daily intakes of crude protein among the 3 groups. Formation of struvite crystals and balance of calcium, phosphorus, and magnesium were measured. RESULTS: Urine volume was lower in the starch group and fiber group in study 1, whereas no differences were detected among the groups in study 2. Urinary pH and struvite activity product were higher in the starch group in both studies, and the fiber group also had higher struvite activity product in study 2. In both studies, urinary concentrations of HCl-insoluble sediment were higher in the starch group and fiber group. In the fiber group, a net loss of body calcium, phosphorus, and magnesium was detected in study 2. CONCLUSIONS AND CLINICAL RELEVANCE: Starch and fiber in diets potentially stimulate formation of struvite crystals. Hence, reducing dietary carbohydrate is desirable to prevent struvite urolith formation. In addition, a net loss of body calcium, phosphorus, and magnesium during feeding of the fiber diet suggests that dietary inclusion of insoluble fiber could increase macromineral requirements of cats.  相似文献   

15.
Prednisolone (10 mg PO q24h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received prednisolone, 24-hour urine pH was lower and 24-hour urine excretion of creatinine, magnesium, phosphate, and potassium was higher than when cats received placebo. No significant difference was found in urinary relative supersaturation for calcium oxalate (CaOx) or struvite between treatment groups. Prednisolone administration did not induce diuresis, nor was it associated with increased calcium excretion or urinary saturation for CaOx in these healthy cats. Results of this study, however, should not be extrapolated to cats that form CaOx uroliths associated with idiopathic hypercalcemia.  相似文献   

16.
Etiopathogenesis of canine struvite urolithiasis   总被引：1，自引：0，他引：1  
Urine must be oversaturated with magnesium ammonium phosphate for struvite uroliths to form. Oversaturation of urine with magnesium ammonium phosphate may be associated with several factors, including urinary tract infections with urease-producing microbes, alkaline urine, diet, and genetic predisposition. Of the urease-producing microbes, staphylococci are most struvitogenic in dogs. The precise mechanisms resulting in formation of sterile struvite uroliths in dogs have not been determined.  相似文献   

17.
Four adult, castrated, male ferrets were studied in two similar trials for effects of food intake on variables hypothesized to promote struvite (ammonium, magnesium, phosphate hexahydrate) crystal formation in urine. Struvite crystalluria occurred in three of the four ferrets. Urine pH (UpH) averaged 6.6 for these ferrets. UpH in the ferret without crystalluria was 6.0. By simple linear regression analysis, no relationship was found between the amount of food ingested and the urinary concentration and excretion of magnesium and phosphorous. However, urine osmolality and excretion of both protein and ammonium were correlated to food intake (P<.05). Ways in which these effects could promote struvite crystal formation are discussed.This research was supported in part, by Grants No. BRSG 50507 RR07021-14 (DSR) and BRSG RR05788-03 (CVM). Florida Agriculture Experiment Station Journal Series No. 3305  相似文献   

18.
The nutritional value of meat meal (MM), chicken meal (CM), and corn gluten meal (CGM) as dietary sources of protein in dry food formulated for adult cats was evaluated. Twelve healthy adult cats (11 males and 1 female) were used. Dry diets containing MM, CM, or CGM as the main protein source were given for a 3-week period in a 3 x 3 Latin-square design. Digestion and balance experiments were conducted during the last 7 d of each period. In addition, freshly voided urine was taken to determine urinary pH and number of struvite crystals. As compared with the CM diet, dry-matter digestibility was higher and lower for the MM and CGM groups, respectively. Percentages of nitrogen (N) absorption and N retention to N intake were higher in the MM group, and N utilization was not different between the CM group and the CGM group. All cats excreted alkaline urine (pH > 7). Urinary pH, struvite activity product, and number of struvite crystals in urine were lower for the CGM group. There was no difference in retention of calcium and magnesium among the groups. From the point of view of digestibility and N utilization, MM is superior to CGM, and CM is better than or equivalent to CGM as a protein source of dry foods for adult cats. However, when CM is used as a dietary protein source, some manipulation of dietary base excess may be needed to control urinary acid-base balance, because CM contains higher calcium and phosphorus.  相似文献   

19.
Hydrochlorothiazide (1 mg/kg PO q12h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received hydrochlorothiazide, 24-hour urine volume, ammonia, chloride, creatinine, magnesium, oxalic acid, phosphate, potassium, and sodium were significantly higher than when cats received placebo. Hydrochlorothiazide was associated with significantly lower urinary saturation for calcium oxalate, but no difference was found in 24-hour urine calcium and citrate, urinary saturation for struvite, or blood ionized calcium. Hydrochlorothiazide decreased urinary saturation for calcium oxalate and could be useful in managing cats with calcium oxalate uroliths. Results of this study, however, should not be extrapolated to cats that form calcium oxalate uroliths.  相似文献   

20.
The clinical problems and results of urinalyses of 500 dogs were reviewed and summarized to compare the sensitivities for detection of abnormalities indicative of urinary system disease among qualitative (sulfosalicylic acid [SSA]), quantitative (Coomassie brilliant blue [CBB]), and indexed (urinary protein/creatinine ratio [U(P/C)]) determinations of urinary protein loss vs microscopic examination of urine sediment. False-negative rates for the detection of microscopically abnormal urine specimens were 5.4% for SSA greater than or equal to 1+, 8.5% for CBB greater than or equal to 1.0 mg/ml, 9.7% for U(P/C) greater than or equal to 1.0, and 7.7% for CBB + U(P/C). A discriminatory U(P/C) value of 2.0 would have excluded dogs with clinically relevant proteinuria in the lower ranges. Proteinuria was not detected in 4.4% (22/500) of the specimens in which important numbers of leukocytes or bacteria were observed. False-negative rates for combined interpretation of quantitative protein concentration and U(P/C) were not significantly different (P greater than 0.10) from SSA alone. Degrees of azotemia were higher (high serum creatinine concentration, P greater than 0.10 and high serum urea nitrogen concentration, P less than 0.05) and prevalence of chronically diseased dogs was greater (P less than 0.005) in dog categories with higher U(P/C) values. More quantitative determinations of urinary protein loss as a screening test offer potential labor-saving and diagnostic advantages in the identification of urinary disease over more qualitative routine screening methods.  相似文献   

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