Faecal dry matter excretion per se affects faecal calcium and phosphorus losses in dogs.

The study aimed to investigate the effect of faecal dry matter (DM) excretion on faecal losses of calcium (Ca) and phosphorus (P) without potentially confounding factors. Dogs were fed two levels of the same basal diet (cooked pork, rice, gelatine; 8.5 ± 0.7 and 12.6 ± 1.2 g DM/kg BW). Mineral supplements were added separately for identical Ca and P supply independent of DM intake (Ca 226 and P ~170 mg/kg BW). Digestion trials (10 days adaptation, 5 days quantitative faecal collection) were carried out. Digestibility of DM averaged 87% in both trials. Faecal DM and mineral excretion increased highly significant (DM 1.1 ± 0.3 to 1.7 ± 0.2 g/kg BW, p = 0.00005; Ca 185 ± 34 and 233 ± 22 mg/kg BW, p = 0.00119; P 99 ± 23 to 127 ± 12 mg/kg BW, p = 0.00212), revealing a highly significant correlation. Apparent digestibility of Ca was positive in the first trial and negative in the second leading to a slightly negative Ca retention in the latter one. The results suggest that in dogs (i) factors influencing Ca and P absorption can only be compared if faecal DM excretion is identical and (ii) Ca requirements may be affected by DM intake and digestibility.

The effect of crude protein content of the diet on renal energy losses in horses.

Renal energy losses of horses are high in comparison with other species. In the present study, more data were obtained on this parameter to improve predictive equations for renal energy losses. Four adult ponies (247-344 kg body weight [BW]) were fed with eight different diets based on first cut hay, second cut hay, early first cut fresh grass, late cut herbs-grass mix, early cut clover-grass mix, sugar beet pulp, rice bran and straw. Feed intake was measured, and urine and faeces were quantitatively collected for 3 × 12 hr at daytime and afterwards 3 × 12 hr at nighttime. Feed was analysed for crude nutrients, gross energy, amino acids and neutral-detergent-insoluble crude protein (NDICP); faeces were analysed for crude nutrients and gross energy; and urine was analysed for nitrogen (N) and gross energy. Renal energy losses per gram dry matter (DM) intake (y; kJ/g DM) were strictly correlated to protein content in DM (x; g/kg DM): y = 0.325 + 0.00431x; r2  = .81; n = 38; p < .001. The data suggest that the intercept represents energy losses by detoxification products such as hippuric acid and the regression coefficient by protein metabolites such as urea.

Canine symmetrical lupoid onychomadesis in bearded collies.

BACKGROUND: Symmetrical lupoid onychomadesis (SLO) is a disease not infrequently seen in bearded collie dogs in Germany. OBJECTIVES: The aim of this study was to compare historical and clinical data, as well as the mineral content of the hair and claws of bearded collies with SLO with that of normal control dogs. ANIMALS: Twenty-eight affected bearded collie dogs and 39 control dogs. METHODS AND MATERIALS: Owners completed an extensive questionnaire regarding upbringing, environmental conditions and diets. Claw specimens were obtained by claw trimming or gathering lost claws; hairs were obtained by plucking samples from several areas of the body; samples were converted to ash and evaluated in an atomic absorption spectrophotometer. RESULTS: Clinical signs in affected dogs eventually involved all claws on all paws. In twelve dogs recurrence of onychomadesis was observed. There was no relevant association between gender, housing, diet and health management, physical stress and the development of SLO with exception of the age at which more intense exercise began. The most commonly used treatment combination was fatty acids, pentoxifylline and tetracycline; improvement occurred in 17 animals. Calcium, sodium and phosphorus concentrations were higher in the claws of affected dogs, whereas zinc concentrations were lower. The mineral content of hair samples of the affected dogs was not significantly different than controls. CONCLUSION AND CLINICAL IMPORTANCE: Symmetrical lupoid onychomadesis in bearded collies is clinically similar to what has been described in other breeds with regard to clinical signs and response to treatment. Early strenuous activity may increase the risk for disease occurrence in this breed.

Metabolisable energy intake and growth of privately owned growing dogs in comparison with official recommendations on the growth curve and energy supply.

The correct assumption of metabolisable energy (ME) requirement is essential for the nutrition consultation and diet formulation. In young dogs, too high energy supply can accelerate growth and thus lead to developmental orthopaedic diseases. The aim of the present study was to collect the data on ME intake and body weight (BW) development in privately owned growing dogs in order to compare these data with the current recommendations. Our hypothesis was that the actual ME intake of healthy young dogs would be lower than the actual recommendation. The data of 493 privately owned puppies (median age at first consultation 21 weeks, the median expected mature BW 30 kg) on ME intake, actual and expected mature BW were collected and compared with recommendations of the Society of Nutrition Physiology (GfE, Meyer and Zentek and NRC). In 243 dogs, there was a follow-up. The actual BW did not deviate systematically from the calculated expected BW (R2  = .929). The ME intake significantly decreased with age (p < .05) and significantly increased with expected mature BW (p < .05). There was no significant interaction between these two parameters (p > .05). Sex had no effect on the ME intake (p > .05). The ME intake of young dogs with a history of skeletal problems or of food allergy did not differ systematically from healthy dogs of similar age and expected mature BW. The ME intake was considerably below NRC recommendations, especially in younger puppies (>8-17 weeks: 78%, >17-26 weeks: 83% of NRC recommendation). A predictive linear equation for ME intake was developed: ME intake (MJ) = (1.063 - 0.565 × [actual BW/expected mature BW]) × actual BW0.75 .

A pilot study on in vitro solubility of phosphorus from mineral sources, feed ingredients and compound feed for pigs, poultry, dogs and cats.

Excess phosphorus (P) as seen in cat foods can have a negative effect on health (Dobenecker, Webel, Reese, & Kienzle, ; Pastoor, Klooster, Mathot, & Beynen, ). P surpluses may affect the environment, and economics in food producing animals, whereas marginal supply may impair performance and health. P can only be absorbed if it is soluble. Solubility of feed P in water and weak acid solution-as a precondition for absorption-was investigated in feed for dogs, cats, pigs and poultry. Different P containing mineral compounds (Ca(H2 PO4 )2 , CaHPO4 •2H2 O, Ca4 Na(PO4 )3 , KH2 PO4 , K4 P2 O7 , NaH2 PO4 , Na5 P3 O10 (29 samples), as well as eight different ingredients such as wheat or meat, 64 compound feeds for pig and poultry, eight complete dry and 13 complete moist dog foods, 25 complete moist cat foods and 29 experimental diets were analysed for P solubility. Finely ground feeds were soaked in water or hydrochloric acid (0.4%) for 1 and 90 min. The samples were centrifuged and the supernatant was analysed for P (photometric vanadate molybdate method after wet ashing). The solubility of P from inorganic sources reflected the solubility of the main compound of the feed grade material. "organic" ingredients, such as fish meal or meat, showed a lower P solubility than inorganic sources. Most ingredients from animal origin (exception fish meal) had a higher P solubility than those from plant origin. When inorganic and "organic" P sources were mixed, the P solubility of the mixture reflected the P solubility and percentages of its compounds. In chicken, turkey and pig compound feed the percentage of acid soluble P increased with increasing P content. Pet moist food showed high percentages of water-soluble P. The results show that the method is suitable to obtain data on water and acid solubility of P in feed and ingredients.

Renal phosphorus excretion in adult healthy cats after the intake of high phosphorus diets with either calcium monophosphate or sodium monophosphate.

Renal and faecal phosphorus excretion of adult healthy European shorthaired cats after the intake of high phosphorus diets (meat/rice based) with either calcium monophosphate (HP-CaP) or sodium monophosphate (HP-NaP) as main phosphorus source was compared. The control diets (CON-CaP and CON-NaP, respectively) did not contain any added phosphorus. Calcium/phosphorus ratio was adjusted to 1.3/1 by adding calcium carbonate. Twenty-three cats were available for the trials. All cats were fed the control diets for 29 days; then, the HP diets were tested for 29 days against controls in a crossover design. Faeces and urine were collected in the last 10 days of each trial. Phosphorus in food, faeces and urine was measured by photometry after wet digestion. Phosphorus intake amounted to 84 ± 10 mg/kg body weight (BW) in CON-NaP (n = 13) and to 74 ± 7 in CON-CaP (n = 12). In the HP groups, the intake was 255 ± 34 mg/kg BW (HP-NaP; n = 13) and 216 ± 20 mg/kg BW (HP-CaP; n = 12). The sodium monophosphate in group HP-NaP led to a higher renal phosphorus excretion (83 ± 15 mg/kg BW) than the calcium monophosphate (25 ± 5 mg/kg BW; p < 0.05), even though the apparent phosphorus digestibility was higher in HP-CaP than in HP-NaP (p < 0.05). Faecal calcium excretion was strictly correlated to faecal phosphorus excretion (r2  = 0.98). The same was true for calcium and phosphorus balance (r2  = 0.89). In group HP-NaP, seven of 13 cats showed glucosuria. By contrast, in HP-CaP glucosuria was not observed. Highly water-soluble inorganic phosphorus sources such as sodium phosphate are likely to lead to phosphaturia and may present a risk for renal health of cats.

Digestive physiology of the plains viscacha (Lagostomus maximus): A large herbivorous hystricomorph rodent.

Plains viscachas (Lagostomus maximus) are large South American, fossorial rodents susceptible to diabetic cataracts. Various aspects of their digestive physiology were studied in three different experiments with nine male and seven female adult animals and six different diets (total n of feeding trials = 35). Viscachas achieved mean retention times of 23­31 hr, which is of a magnitude also recorded in horses; these did not differ for solute or small particle (<2 mm) markers. Secondary marker excretion peaks indicated coprophagy, and were rarer on high-protein as compared to grass hay-only diets. Mean resting metabolic rate was, at 229 kJ/kg0.75/day, lower than expected for a mammal of this size. Digestible energy requirement for maintenance was 445 kJ/kg0.75/day. At 1.6­2.7 L/day, viscachas produced more methane than expected for a hindgut fermenter of their size. On diets that included concentrate feeds, viscachas excreted glucose in their urine, corroborating reports on the susceptibility of this species for diabetes when kept on energy-dense food. Viscachas had a similar apparent digestibility of protein, lipids, and macrominerals as other rodents, rabbits, or domestic horses. This suggests that whether or not a species practices coprophagy does not have a major influence on these measures. Viscachas resemble other hindgut fermenters in their high apparent calcium digestibility. With respect to a digestibility-reducing effect of dietary fiber, viscachas differed from rabbits and guinea pigs but were similar to horses, suggesting that small body size needs not necessarily be linked to lower digestive efficiency on high-fiber diets.

True mineral digestibility in C57Bl/6J mice.

Data on mineral digestibility is key to understand mineral homeostasis and refine the recommendations for the dietary intake of these nutrients. In farm animals and pets, there is plenty of data on mineral digestibility and influencing factors. In laboratory mice, however, there is a lack of information on mineral digestibility under maintenance conditions, although this should be the basis for studies on mineral homeostasis under experimental conditions. The aim of the present study was to analyse data on intake, faecal excretion, and apparent digestibility of calcium, phosphorus, sodium, potassium, and magnesium in C57BL/6J mice fed different maintenance diets with varying voluntary dry matter intake. Lucas-tests were used to quantify true digestibility and describe correlations between dietary intake and excretion/absorption of the nutrients. Calcium, phosphorus, and magnesium showed a linear correlation between intake and faecal excretion (R2: 0.77, 0.93 and 0.91, respectively). Intake and apparently digested amounts of sodium and potassium were correlated linearly (R2: 0.86 and 0.98, respectively). These data show that intake is the major determinant of absorption in the minerals listed above. Faecal calcium and phosphorus excretion were correlated as well (R2 = 0.75).

Comparative analysis of pancreatic amylase activity in laboratory rodents.

Alpha-amylase is the main enzyme for starch digestion in the mammalian gastrointestinal tract. There are species differences in the enzymatic activity of pancreatic amylase that are related to the digestive strategy and natural diet of a species. This aspect is well investigated in pet and farm animals, while in common laboratory animal rodents, information is scarce. In the context of the 3R concept, detailed knowledge of the digestive physiology should be the basis of adequate nutrition, experimental planning and data interpretation. The present study aimed to obtain reference data on amylase activity in pancreatic tissue and duodenal digesta in laboratory mice, rats and hamsters. In addition, digesta was stained with Lugol's iodine to visualize starch in the process of degradation throughout the gastrointestinal tract. Amylase activity in pancreatic tissue and duodenal digesta was significantly lower in hamsters than rats and mice. The Lugol staining showed intense starch degradation in the hamsters' forestomachs, presumably by microbial fermentation. A possible explanation is that the prae-duodenal microbial starch fermentation enhances digestibility and reduces the need for pancreatic amylase in hamsters. Rats and mice may rely more on pancreatic amylase for prae-caecal starch digestion, while the microbial fermentation is mainly located in the caecum. The results clearly show species differences in the digestive capacity for starch in mice, rats and hamsters that need to be considered in the feeding of these species in the laboratory setting as well as in the use of rodents as translational animal models.

Chemical composition of snakes.

The present study was carried out to provide insight into the body composition of snakes, which is an important basis for determination of nutrient requirement and physiological processes. Carcasses of 86 captive snakes (31 pythons, 32 colubrids and 23 boas) were available for analysis. Skins and vertebrae bones of 11 snakes and livers of 64 snakes were analysed separately from the carcasses. Crude nutrients, major minerals and trace elements were investigated. The content of crude nutrients of the whole body was similar to those of mammals and birds. Relatively high contents of copper, zinc and especially of iron (up to 23,973 mg/kg dry matter) were found in the body, particularly in the liver. There was an increase of the iron content of the whole body over age.

High Intake of Sodium Chloride for 28 Days Causes No Effect on Serum FGF23 Concentrations in Cats.

BACKGROUND: FGF23 is an acknowledged parameter to assess kidney health. As chronic kidney failure is one of the most common diseases in aging cats, dietary influences on renal health warrant investigation. The purpose of this study was therefore to investigate potential correlations between dietary sodium chloride and FGF23. METHODS: In a total of two trials, 11 cats were included. In the first trial, the cats were fed a complete and balanced control diet; in the second trial, sodium chloride was added (8 g/kg/DM)). Blood, urinary, feed, and faecal samples were analysed for major minerals. FGF23 and creatinine were measured in blood and urine samples. RESULTS: Serum phosphate and FGF23 were unaffected by high sodium chloride intake, thus showing no correlation between serum FGF23 and sodium concentrations. Apparent phosphorus digestibility was significantly increased, however, by high sodium chloride intake, whereas apparent digestibility of calcium was unaffected. The present study confirms differences in FGF23 and sodium chloride interaction in cats compared with other species. Further research regarding the correlation between sodium chloride and phosphate homeostasis is warranted.

A pilot study on dietary and faecal calcium/phosphorus ratios in different types of captive ruminating herbivores.

Quantitative differences in calcium and phosphorus metabolism between domestic species exist and can be visualised using data on calcium and phosphorus intake and faecal excretion. The parameter for analysing the results was defined as Δ = dietary calcium/phosphorus (Ca/P) ratio - faecal Ca/P ratio. In previous studies, hindgut fermenters had significantly higher Δ values than ruminants (sheep, cattle, goats), which was explained by the high calcium digestibilities in hindgut fermenters in contrast to highly efficient phosphorus recycling in ruminants. The first hypothesis of the present study was that different types of ruminants (grazer, browser, intermediate feeder) would show differences in Δ as a proxy for quantitative calcium and phosphorus metabolism. The second hypothesis was that camelids as functional, but not taxonomic ruminants would show Δ values similar to ruminants. We used herbivorous zoo animals (17 species, hindgut and foregut fermenters), which were kept on their regular diet without variation for 1 week. Then, faecal samples were obtained from the individual animals. Feed items and faecal samples were analysed for calcium and phosphorus, and dietary and faecal Ca/P ratios as well as Δ were calculated. A comparison of the species groups (one-way ANOVA on ranks, p < 0.05) showed that zoo hindgut fermenters had significantly higher Δ values (0.67 ± 0.34) than camelids and zoo ruminants (-1.07 ± 0.35 and -1.87 ± 1.56). There was no significant difference between camelids, grazers (-1.49 ± 1.31), browsers (-1.63 ± 0.88) and intermediate feeders (-2.11 ± 1.76). The ruminant species from this study had markedly lower Δ than domestic ruminants from literature data. Especially intermediate feeders had low Δ, possibly due to more efficient phosphorus recycling than the domestic ruminants.

Morphometrics of Xenopus laevis Kept as Laboratory Animals.

Morphometric data that provide information on body conditions can be used to monitor the health and well-being of animals. In laboratory animals, they can help to evaluate the stress due to experiments or treatments, following the 3R principles. The aim of the present study was to obtain morphometric data of male and female African clawed frogs, Xenopus laevis, as the bases for body condition evaluations. Adult frogs (n = 198) were weighed and standardized photographs were taken. The photographs were used to determine several measurements (length, cranial width, caudal width, thigh width). In addition, a triangle was drawn to outline each frog's simplified body form, and the triangle surface was calculated. In conclusion, the triangle surface drawn on the dorsal plane of each frog correlated with the body weight of the females. There were significant differences between the body weights and sizes of male and female frogs, with males being smaller (p < 0.001). Based on the morphometric data, females could be assigned to five groups in which an assessment of the animal's well-being is feasible.

Morphology of Starch Particles along the Passage through the Gastrointestinal Tract in Laboratory Mice Fed Extruded and Pelleted Diets.

Diet processing impacts on starch properties, such as the degree of starch gelatinization. This affects digestibility, as shown in laboratory mice fed either a pelleted or an extruded diet. In the present study, the morphology of starch particles throughout the digestive tract of mice was visualized. Thirty-two female C57BL/6J mice were used for a feeding trial. They were fed a commercial maintenance diet for laboratory mice, which was available in pelleted and extruded form, for seven weeks. The mice were sacrificed after the feeding period, and chyme samples were collected from five sites (stomach, anterior and posterior small intestine, caecum, colon). Samples of diets, chyme and faeces were analyzed via stereomicroscopy (stained with Lugol's iodine) and scanning electron microscopy (SEM). The starch granules appeared more compact in the pelleted diet, showing first signs of degradation only in the small intestine. The caecum content of both diets group was intensively stained, particles as well as fluid phase, indicating that it contained mainly starch. The SEM pictures of caecum content showed abundant bacteria near starch particles. This suggests selective retention of prae-caecally undigested starch in the murine caecum, likely the site of microbial fermentation.

Induction of ketosis in rats fed low-carbohydrate, high-fat diets depends on the relative abundance of dietary fat and protein.

Low-carbohydrate/high-fat diets (LC-HFDs) in rodent models have been implicated with both weight loss and as a therapeutic approach to treat neurological diseases. LC-HFDs are known to induce ketosis; however, systematic studies analyzing the impact of the macronutrient composition on ketosis induction and weight loss success are lacking. Male Wistar rats were pair-fed for 4 wk either a standard chow diet or one of three different LC-HFDs, which only differed in the relative abundance of fat and protein (percentages of fat/protein in dry matter: LC-75/10; LC-65/20; LC-55/30). We subsequently measured body composition by nuclear magnetic resonance (NMR), analyzed blood chemistry and urine acetone content, evaluated gene expression changes of key ketogenic and gluconeogenic genes, and measured energy expenditure (EE) and locomotor activity (LA) during the first 4 days and after 3 wk on the respective diets. Compared with chow, rats fed with LC-75/10, LC-65/20, and LC-55/30 gained significantly less body weight. Reductions in body weight were mainly due to lower lean body mass and paralleled by significantly increased fat mass. Levels of ß-hydroxybutyate were significantly elevated feeding LC-75/10 and LC-65/20 but decreased in parallel to reductions in dietary fat. Acetone was about 16-fold higher with LC-75/10 only (P < 0.001). In contrast, rats fed with LC-55/30 were not ketotic. Serum fibroblast growth factor-21, hepatic mRNA expression of hydroxymethylglutaryl-CoA-lyase, peroxisome proliferator-activated receptor-γ coactivator-1α, and peroxisome proliferator-activated receptor-γ coactivator-1ß were increased with LC-75/10 only. Expression of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase was downregulated by 50-70% in LC-HF groups. Furthermore, EE and LA were significantly decreased in all groups fed with LC-HFDs after 3 wk on the diets. In rats, the absence of dietary carbohydrates per se does not induce ketosis. LC-HFDs must be high in fat, but also low in protein contents to be clearly ketogenic. Independent of the macronutrient composition, LC-HFD-induced weight loss is not due to increased EE and LA.

A pilot study of the body weight of pure-bred client-owned adult cats.

A total of 539 pure-bred and seventy-five cats without a pedigree were weighed and scored at cat shows or in veterinary surgeries. Data from normal-weight cats with a body condition score (BCS) of 5 (ideal) were only used. Breeds were grouped into five classes. For female cats, the mean weight for these groups were as follows: very light (2.8 kg); light (3.2 kg); medium (3.5 kg); large (4.0 kg); giant (4.9) kg. For male cats, the corresponding values were 3.6, 4.2, 4.3, 5.1 and 6.1 kg. Siamese/Oriental Shorthair were identified as a very light breed, the Norwegian Forest and the Siberian Cat as a large breed and the Maine Coon as a giant breed. Males and females of the same breed did not always belong to the same class. In some breeds, individuals of the same sex were found in two different classes. The percentage of intact overweight cats (BCS >5) was low (7 % of intact males, 3 % of intact females). Incidence of overweight in neutered cats was 50 % in males and 38 % in females. Among pedigreed cats, there were differences in the incidence of overweight in neutered cats: high in Norwegian Forest Cats (males 75 %, females 50 %) and low in Siamese/Oriental Shorthair Cats (males 25 %, females 1 %). Cats with a BCS of 6, 7 and 8 had on average 120, 154 and 214 % of the normal weight of their breed, respectively.

Birth weight and postnatal growth of pure-bred kittens.

Data on body weight of pure-bred kittens (Maine Coon, Norwegian Forest Cat, Birman, Persian, Siamese/Oriental Shorthair Cat) from birth (n 245) to 12 weeks of age (n 135) were obtained from breeders. Absolute birth weight (in g) was higher in larger breeds than in smaller breeds, whereas relative birth weight (in % of mature female weight) tended to be higher in smaller breeds (Maine Coon 115 g, 2.3 %; Norwegian Forest Cat 106 g, 2.7 %; Birman 97 g, 2.8 %; Siamese 92 g, 2.8 %; Persian 82 g, 3.2 %). Relative birth weight was lower than that described in the literature for colony cats. Relative litter weight was highest in Norwegian Forest Cats (14.6 (SD 1.8) %; n 10) and lowest in Birmans (8.8 (SD 3.1) %, n 7; P < 0.05); the other breeds were in-between (11.9 (SD 2.0) %; n 19). Absolute growth was faster in larger breeds than in smaller breeds. In relation to expected mature weight, there was good agreement with data from colony cats but no clear-cut effect of breed size. There appeared to be a trend to an earlier onset of sexual dimorphism in larger breeds.

Intake of minerals, trace elements and vitamins in bone and raw food rations in adult dogs.

The aim of the present study was to evaluate the vitamin and mineral content of bone and raw food rations fed to adult dogs in Germany. Pet owners completed a standardised feeding questionnaire. The composition of 95 rations was calculated from mean data for foodstuffs using nutrition balancing software. Typical ration ingredients were meats, fish, offal, dairy products, eggs, oil, nuts, cod liver oil and natural and commercial supplements. The supply of nutrients was compared with the recommended allowance (RA). Of the rations that were used, 10 % supplied < 25 % of the RA of Ca. In these rations, Ca:P was below 0.6:1, and vitamin D was below RA. About half of the rations supplied less iodine than the minimum requirement. Many of the rations had low Zn and Cu supply, and 25 % of the rations supplied only 70 % of RA for vitamin A or less. A total of 60 % of the rations had one or more of the above-mentioned imbalance. The remaining 40 % of rations either had minor problems like Ca excess from bones or they were balanced.

The Source Matters-Effects of High Phosphate Intake from Eight Different Sources in Dogs.

Elevated serum phosphate concentrations are an established risk factor for cardiovascular disease and mortality in chronic kidney disease in various species. Independent associations of other parameters of phosphorus metabolism, such as phosphorus intake from different sources and serum concentrations of phosphorus, as well as parameters involved in the regulation, such as parathyroid hormone (PTH) or markers of bone turnover, have been studied in less detail. Therefore, the serum kinetics of phosphate, PTH, and the bone resorption marker bone-specific alkaline phosphatase (BAP) were investigated after 18 days of feeding a control diet and diets supplemented with eight different organic and inorganic phosphate sources aiming at 1.8% phosphorus per dry matter and calcium to phosphorus ratio between 1.3 and 1.7 to 1. Eight healthy beagle dogs (f/m, 2-4 years, 12.9 ± 1.4 kg body weight) were available for the trial. Highly significant differences in the serum kinetics of phosphorus, PTH, and BAP with the highest postprandial levels after feeding highly water-soluble sodium and potassium phosphates were found. We conclude that the use of certain inorganic phosphates in pet food is potentially harmful and should be restricted.

Influence of Strain and Diet on Urinary pH in Laboratory Mice.

Acid base homeostasis and urine pH is influenced by the dietary cation anion balance (DCAB) in many species. Here, a negative DCAB acidifies the urine, while higher DCABs alkalize the urine. The dimension of the DCAB effect can be species-specific, because of differences in urine buffer systems. The aim of the present study was to describe the response of laboratory mice to diets with different DCAB. We used 8-week-old wildtype male mice of the C57Bl/6J inbred strain and CD1 outbred stock. Three groups (n = 15 animals/group) were formed and fed standard diet A for adaptation. For the 7-week feeding trial, mice were either kept on diet A (DCAB -7 mmol/kg dry matter (DM) or switched to diet B (246 mmol/kg DM) or C (-257 mmol/kg DM). Urine pH was measured weekly from a pooled sample per cage. There was a significant difference in the basal urine pH on diet A between C57Bl6/J and CD1 mice. The shift in urine pH was also significantly different between the two groups investigated.