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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

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.

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

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, Ruminating herbivores differ in their gastrointestinal anatomy and physiology, having adapted to their natural diet. This study investigates differences in calcium and phosphorus metabolism in non‐domestic ruminants and camelids, presenting first data on such species.

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 β-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-1β were increased with LC-75/10 only. Expression of phospho enolpyruvate 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.

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). 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 .

In our nutrition consultation service we observed liver disease in 2 dogs of one owner who was feeding buckwheat. This led to the hypothesis that buckwheat may cause problems. The present retrospective study in a German and a Russian nutrition consultation service was carried out to see whether there is an increased incidence of liver disease in dogs fed buckwheat.A retrospective study was carried out on the nutrition consultation cases of the Chair of Animal Nutrition and Dietetics, LMU Munich and a Russian nutrition consultant. All cases of dogs with buckwheat in their nutritional history were evaluated and compared with randomly selected dogs that had not been fed buckwheat from the same case set. Two German and 1 Russian buckwheat samples were compared (appearance, nutrient content, starch gelatinization, flavonoids, fagopyrin) as well as cooking methods.In the years 2007-2017, 34 cases of dogs fed buckwheat were identified in Germany and 57 in Russia. Eighty-five control cases in Germany and 48 in Russia were evaluated. In Germany, the incidence of liver disease in dogs fed buckwheat was 32 %, while that of the control group was 3.5 %. However, in Russia there was no significant difference between dogs fed buckwheat and control dogs. The appearance of the German and Russian buckwheat differed, with smaller seeds and more greenish colour in the German specimens while the Russian buckwheat presented larger and more brownish seeds. There was no difference in the analyses of the 3 buckwheat samples in crude nutrient and rutin content. Quercetin, quercitrin and fagopyrin were not detectable in all three samples. The degree of starch gelatinization in the Russian sample was higher than in the German. In Russia it is recommended to remove the reddish scum during boiling whereas this is rarely mentioned in Germany.German buckwheat may represent a risk in canine diets. With the difference remaining unclear, it is recommended to refrain from feeding buckwheat to dogs. In dogs fed homemade diets and suffering from liver disease, buckwheat should be considered in the nutrition history.In unserem Ernährungsberatungsdienst beobachteten wir Lebererkrankungen bei 2 Hunden eines Besitzers, die mit Buchweizen gefüttert wurden. Diese retrospektive Studie wurde in jeweils einer deutschen und einer russischen Ernährungsberatungspraxis durchgeführt, um festzustellen, ob eine erhöhte Inzidenz von Lebererkrankungen bei Hunden besteht, die mit Buchweizen gefüttert wurden.Alle Fälle der mit Buchweizen ernährten Hunde in den beiden Ernährungsberatungspraxen wurden überprüft und mit einer Kontrollgruppe zufällig ausgewählter Hunde verglichen, deren Ration keinen Buchweizen enthielt. Es erfolgte ein Vergleich von 2 deutschen und einer russischen Probe hinsichtlich Aussehen, Nährstoffgehalt, Stärkeaufschlussgrad sowie Gehalt an Flavonoiden und Fagopyrin. Ferner wurde die landestypische Kochmethode für Buchweizen recherchiert.In den Jahren 2007–2017 ließen sich 34 Fälle aus Deutschland und 57 Fälle aus Russland identifizieren, in denen Buchweizen an Hunde verfüttert wurde. Die Kontrollgruppe umfasste 85 Fälle in Deutschland und 48 in Russland. Die Inzidenz von Lebererkrankungen betrug in Deutschland bei mit Buchweizen gefütterten Hunden 32 % im Vergleich zu 3,5 % in der Kontrollgruppe. In Russland differierte die Inzidenz von Lebererkrankungen zwischen beiden Gruppen nicht signifikant. Das Aussehen des deutschen und russischen Buchweizens war unterschiedlich, mit kleineren und grünlichen Samen in den deutschen Proben und bräunlicher Farbe der russischen Probe. Kein Unterschied wurde zwischen den 3 Buchweizenproben hinsichtlich Rohnährstoffgehalt und Rutingehalt festgestellt. In keiner Probe ließ sich Quercetin, Quercitrin oder Fagopyrin nachweisen. Der Stärkeaufschlussgrad war in der russischen Buchweizenprobe höher als in den deutschen Proben. In Russland wird empfohlen, den rötlichen Schleim während des Kochvorgangs zu entfernen, während dies in deutschen Rezepten selten erwähnt wird.Relevanz Das Verfüttern von deutschem Buchweizen kann für Hunde ein Risiko darstellen. Bis geklärt ist, worin seine potenziell schädliche Wirkung besteht, sollte das Verfüttern von Buchweizen an Hunde vermieden werden. Bei Hunden mit einer Lebererkrankung sollte Buchweizen in der Fütterungsanamnese berücksichtigt werden.

Zusammenfassung Gegenstand und Ziel Speziesunterschiede im Kalzium- und Phosphorstoffwechsel lassen sich quantitativ über die Berechnung der Kalzium/Phosphor-Quotienten in Futter und Kot darstellen. In der vorliegenden Meta-Analyse wurde überprüft, ob auf diese Weise eine Aussage zur Phosphorverdaulichkeit bei wachsenden Schweinen getroffen werden kann, um einen möglichst einfachen Prüfparameter zu definieren. Dies ist in Fällen sinnvoll, in denen trotz adäquater Kalzium- und Phosphorgehalte des Futters der Verdacht auf einen Phosphormangel besteht. Material und Methoden Es wurden 34 Studien mit phytasesupplementierten Rationen (PHYT; Datensätze n = 110) und entsprechenden Kontrollrationen (CON; Datensätze n = 106) anhand der Parameter Kalzium- und Phosphoraufnahme, fäkale Kalzium- und Phosphorausscheidung und der jeweiligen scheinbaren Verdaulichkeit ausgewertet. Für beide Mineralien kam ein modifizierter Lucas-Test zur Anwendung, indem eine Regressionsberechnung von fäkaler Ausscheidung gegen Aufnahme (beides in mg/kg KM0,75) durchgeführt wurde. Ergebnisse Der Lucas-Test zeigte keinen signifikanten Unterschied der fäkalen Kalziumausscheidung zwischen PHYT und CON (p = 0,29), während der in der Literatur vielfach beschriebene positive Effekt der Phytase auf die Phosphorverdaulichkeit sehr deutlich wurde (p < 0,01). Die fäkalen Kalzium/Phosphor-Quotienten aller Datensätze wurden berechnet und gruppiert, und zwar nach der Körpermasse (KM) der Tiere sowie der scheinbaren Phosphorverdaulichkeit (KM ≤ 30 kg: scheinbare Phosphorverdaulichkeit ≤ 60 % und > 60 %; KM > 30 kg: scheinbare Phosphorverdaulichkeit ≤ 40 % und > 40 %). Schlussfolgerung Aus der Datenverteilung im Box Plot kann – unter der Voraussetzung eines Kalzium/Phosphor-Verhältnisses im Futter von ≥ 1,2 – bei einem fäkalen Kalzium/Phosphor-Quotienten von > 1,5 (für Schweine ≤ 30 kg KM) bzw. > 1,2 (für Schweine > 30 kg KM) auf eine hohe scheinbare Phosphorverdaulichkeit von über 60 % bzw. 40 % geschlossen werden. Klinische Relevanz Werden in Kotproben Kalzium/Phosphor-Quotienten über diesen Schwellenwerten erreicht, ist eine schlechte Phosphorverdaulichkeit somit unwahrscheinlich. Bei fäkalen Kalzium/Phosphor-Quotienten unterhalb dieser „Grenzwerte“ ist keine Einschätzung der Phosphorverdaulichkeit möglich.

Simple Summary Feed for laboratory mice is available in different physical forms. However, there is insufficient standardization in nutrient composition and physical forms. Results pertaining to energy and nutrient digestibility show that differentially processed feed (pelleted vs. extruded) and even batches from the same provider (pelleted vs. pelleted) differ in starch gelatinization. Here we show that feed processing impacts the mice’s gastrointestinal microbiome. Reproducibility and comparability between experiments with differently processed feeds in laboratory mice should not be taken for granted. Therefore, details on dietary ingredients and feed processing should be specified in studies that include animal experiments. Abstract The composition of the microbiome is subject to the host’s diet. In commercial laboratory mouse diets, different physical forms of the same diets are available, containing—according to their labels—identical ingredients and nutrient compositions. However, variations in nutrient composition and starch gelatinization due to production processes and their impact on digestibility have been described. In this study, a total of 48 C57BL/J6 mice were assigned to two equal groups and were fed diets (produced with different processes—extruded vs. pelleted) for eight weeks in two biological replicates. At the end of the experiment, samples were collected from five different gastrointestinal regions, including the stomach, small intestine, cecum, large intestine, and an extracorporeal region (feces), and the microbiome was analyzed with 16S rRNA gene amplicon sequencing. The replicates in both experiments differed significantly in their relative abundances of Muribaculaceae species. Furthermore, the gastrointestinal content of pellet-fed mice contained larger numbers of Lactobacillus species. These results indicate that starch gelatinization and ingredient composition significantly influence microbial makeup. In conclusion, different feed processing methods may affect fundamental digestive and metabolic processes, impacting animal experiments and biasing microbiome data.

Simple Summary Dietary cation anion balance (DCAB) influences urine pH in several species, e.g., cats, dogs, pigs and cattle suggesting a species-specific impact. In the present study, we aimed to explore the impact of three diets with different DACB on wildtype laboratory mice. During a two-month feeding trial urine pH and body weight were measured in C57Bl/6J and CD1 male mice. Remarkable, we observed strong impact of the genetic background and diet on urine pH levels. A plausible explanation is that differences in renal phosphorus excretion and, in turn, phosphate buffering capacity account for these differences. It is tempting to speculate that standard laboratory mouse models show DCAB dependent variations in urine pH. Abstract 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.

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 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 (r(2) = 0.98). The same was true for calcium and phosphorus balance (r(2) = 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.

Zusammenfassung Gegenstand und Ziel: Erfassung der Ernährung von 36 Patienten mit Equine Pituitary Pars Intermedia Dysfunction (PPID) unter Pergolid-behandlung. Tiere, Material und Methode: Ernährungszustand und Futterration wurden zu Beginn der Studie, nach 60 und 120 Tagen bestimmt. Im Rahmen der Pergolidtherapie anfallende Blutproben dienten zur Messung der Glukose- und Insulinkonzentration. Eine Einschätzung der Symptomatik des PPID (z. B. Hypertrichose und Gewichtsveränderungen) durch den Besitzer wurde mithilfe eines standardisierten Fragebogens ermittelt. Ergebnisse: Der Body Condition Score (BCS) auf einer Skala von 1 (Kachexie) bis 9 (Fettsucht) betrug im Mittel 3,1 ± 0,8 (Großpferde 2,7 ± 0,8, Ponys 3,5 ± 0,8). Der mittlere Energiebedarf der Großpferde betrug 74 ± 10 MJ umsetzbare Energie, die geschätzte Aufnahme 65 ± 15 MJ. Zwischen dem BCS und der geschätzten Versorgung mit Energie in Prozent des Bedarfs bestand bei den Großpferden ein signifikanter Zusammenhang. Bei Ponys war der Energiebedarf im Mittel rechnerisch knapp gedeckt. Die Probanden erhielten 2,0 ± 0,7 Raufuttermahlzeiten und höchstens eine Kraftfuttermahlzeit pro Tag (Raufuttermenge 0,2–2,1 kg/100 kg KM). Sechzehn Ponys und ein Großpferd erhielten kein Krippenfutter, fünf Ponys im Mittel 0,15 kg und 14 Großpferde im Mittel 0,8 kg. Zink, Kupfer, Selen, Vitamin A und E wurden meist nicht bedarfsdeckend gefüt tert. Alle Probanden hatten physiologische Plasmaglukosegehalte, die Insulinkonzentration war bei sieben Pferden mindestens zu einem Messzeitpunkt erhöht. Der teilweise sehr schlechte Ernährungszustand der Patienten wurde von einem Teil der Besitzer nicht als Problem erkannt. Schlussfolgerung und praktische Relevanz: Für die Fütterung einer Diät für PPID-Patienten bedarf es in der Praxis differenzierter Anweisungen zu Futtermengen und Mahlzeitenhäufigkeit sowie einer aufwändigen Logistik, da anderenfalls viele Patienten hungern.

There is evidence that nutritional phosphorus (P) excess may be a risk factor for chronic kidney disease (CKD) in humans and pets (Advances in Nutrition: An International Review Journal (2014), 5, 104;The American Journal of Clinical Nutrition, (2013), 98, 6;Journal of Feline Medicine and Surgery, (2017);The source of phosphorus influences serum PTH, apparent digestibility and blood levels of calcium and phosphorus in dogs fed high phosphorus diets with balanced Ca/P ratio. Proc. Waltham International Nutritional Sciences Symposium, USA;Clinical aspects of natural and added phosphorus in foods, 2017, Springer Science+Business, Media). A retrospective study was conducted in order to gather data about P and protein intake in the feeding history of dogs and cats prior to the diagnosis of CKD. Cases of 75 dogs and 16 cats with CKD with comprehensive nutritional history presented to the nutrition consultation service of the Chair of Animal Nutrition and Dietetics, Ludwig-Maximilians-University Munich, between October 2009 and March 2016, were evaluated. Cases of age-matched dogs (n=57) and cats (n=18) without diagnosed or suspected CKD served as controls. The most frequent type of diet used in the four groups (cats CKD, cats control, dogs CKD and dogs control) was home-made. In all groups, P and protein supply was in excess (>150%) of the recommended daily allowances (RDA;Nutrient requirements of dogs and cats (2006), National Research Council, National Academy Press). Between the dog groups, no differences regarding P and protein intake existed. The P and protein intake relative to the RDA was altogether higher in cats than in dogs. Cats with CKD showed significantly higher P and protein intakes prior to diagnosis than the control cats (170 +/- 36 vs. 123 +/- 34mg P/kg BW0.67;p

To investigate the relationship between faecal calcium (Ca) and phosphorus (P) excretion in different mammalian species, a meta-analysis on digestibility data derived from the literature was conducted. Seventy-three studies on carnivores, omnivores, large and small hindgut fermenters, ruminants and hippos (a total of 21 mammalian species, precondition for inclusion dietary Ca/P ratio 1.5/1 - 3.0/1) were analysed for Ca and P digestibility. Dietary Ca/P ratios were lower than faecal Ca/P ratios in carnivores, omnivores, ruminants and hippos. In hindgut fermenters, dietary Ca/P ratios were higher than faecal Ca/P ratios, indicating higher intestinal Ca absorption in these species. In all species investigated, there was a significant positive relationship between Ca intake and faecal Ca excretion and between P intake and faecal P excretion. In the biologically relevant range, these equations predicted lower faecal Ca losses in hindgut fermenters than ruminants, for faecal P vice versa. In all species, faecal Ca and P excretion correlated significantly. In carnivores, this highly linear correlation was exceptionally strong (R² = .92). Yet, the linearity of the correlation was questionable in omnivores and ruminants. Possibly, the strong linear correlation of faecal Ca and P excretion in carnivores is due to the formation of insoluble Ca/P complexes in their relatively short and simple gastrointestinal tract. Another hypothesis is that in carnivores, Ca homeostasis relies on modifying bone turnover to a higher degree than on changes in intestinal Ca absorption. For the formation of bone matrix, a constant ratio of Ca and P absorption is of advantage.

The prediction of renal energy excretion is crucial in a metabolizable energy system for horses. Phenolic acids from forage cell walls may affect renal energy losses by increasing hippuric acid excretion. Therefore, the relationships were investigated between renal energy, nitrogen (N) and hippuric acid excretion of four adult ponies (230-384 kg body weight (BW)) consuming diets based on fresh grass, grass silage, grass cobs (heat-dried, finely chopped, pressed grass), alfalfa hay, straw, extruded straw and soybean meal. Feed intake was measured; urine and faeces were quantitatively collected for three days. Feed was analysed for crude nutrients, gross energy, amino acids and neutral-detergent-insoluble crude protein (CP); faeces were analysed for crude nutrients and cross energy; urine was analysed for N, hippuric acid, creatinine and gross energy. Renal energy excretion (y; kJ/kg BW0.75 ) correlated with renal N excretion (x1 ; g/kg BW0.75 ) and renal hippuric acid excretion (x2 ; g/kg BW0.75 ): y = 14.4 + 30.2x1 +20.7x2 (r = .95; n = 30; p

Objectives High phosphorus intake may further impair renal health in cats with chronic kidney disease (CKD). The hypothesis that a high phosphorus (HP) diet might be nephrotoxic for healthy animals was tested in cats, a species with a high incidence of naturally occurring CKD. Methods Thirteen healthy adult cats were fed a phosphorus excess diet (about five times maintenance requirements), and this HP group was compared with cats on a balanced control diet (CON). The trial lasted for 29 days (10 days of faeces and urine collection). Endogenous creatinine clearance was determined towards the end of the trial. Fresh urine was tested for glucose and proteins. Results Glucosuria and microalbuminuria were observed exclusively in the HP group in 9/13 cats. Creatinine clearance was significantly decreased after feeding HP. In the HP group phosphorus was highly available (apparent digestibility around 60%). Renal phosphorus excretion was significantly increased in the HP group (115 mg/kg body weight/d vs 16 mg/kg body weight/d in the CON group). Conclusions and relevance The intake of a diet with an excessive content of highly available phosphorus may have adverse effects on parameters of kidney function in healthy cats.

In the present investigation, the impact of diet composition on urine pH in rabbits was compared with previous studies on rabbits, cats, dogs, pigs and horses. A total of 13 dwarf rabbits were fed six different diets with a cation-anion balance (CAB) between -39 and +320mmol/kg dry matter (DM) using ammonium chloride (NH4Cl) as an acidifier. CAB was calculated as follows: CAB (mmol/kg DM) = 49.9*Ca + 82.3*Mg + 43.5*Na + 25.6*K - 59*P - 62.4*S - 28.2*Cl;minerals in g/kg DM. Urine, faeces and blood were collected. Urine pH ranged from 5.26 +/- 0.22 at a CAB of -39 mmol/kg DM to 8.56 +/- 0.24 at a CAB of +320mmol/kg DM. A low CAB in the feed reduced blood pH and blood base excess significantly. Renal excretion of Ca, P, Na and Mg and water was significantly higher in rabbits eating acidifying diets. In comparison with other species, rabbits reacted to acidifying diets in a similar way as cats, dogs and pigs. Rabbits on a mildly alkalizing diet, however, had a trend to higher urine pH than other monogastric species on such diets (cats, dogs, pigs, horses).

Species differences in calcium and phosphorus metabolism can be expressed via dietary and faecal calcium/phosphorus ratios. The aim of the present meta-analysis was to use faecal Ca/P ratios as an indicator of phosphorus digestibility in growing pigs as a simple diagnostic tool. This tool can be useful in cases of suspected phosphorus deficiency but adequate dietary calcium and phosphorus contents.Studies (n = 34) with phytase-supplemented (PHYT; n = 110) and non-supplemented control (CON; n = 106) diets were analysed for dietary intake, faecal excretion and apparent digestibility of calcium and phosphorus. A modified Lucas-test was used for both minerals plotting intake against faecal excretion (mg/kg body weightFor calcium, there was no significant difference between PHYT and CON (p = 0.29) while in accordance with literature, the relative faecal phosphorus excretion was significantly lower in PHYT than CON (p0.01). Faecal calcium/phosphorus ratios were calculated and grouped according to the animals' body weight and apparent phosphorus digestibility (body weight ≤ 30 kg: apparent phosphorus digestibility ≤ 60 % and60 %; body weight30 kg: apparent phosphorus digestibility ≤ 40 % and40 %).Data distribution as displayed in a box plot shows that - given a dietary Ca/P ratio of1.2 - faecal Ca/P ratios of1.5 in pigs with a body weight of ≤ 30 kg and of1.2 in pigs with a body weight of30 kg indicate a high apparent digestibility of phosphorus of60 % and40 %, respectively.When faecal samples reveal a Ca/P ratio above the indicated thresholds, a low phosphorus digestibility is unlikely. No conclusion regarding the apparent phosphorus digestibility can be drawn from faecal Ca/P ratios below this threshold.Speziesunterschiede im Kalzium- und Phosphorstoffwechsel lassen sich quantitativ über die Berechnung der Kalzium/Phosphor-Quotienten in Futter und Kot darstellen. In der vorliegenden Meta-Analyse wurde überprüft, ob auf diese Weise eine Aussage zur Phosphorverdaulichkeit bei wachsenden Schweinen getroffen werden kann, um einen möglichst einfachen Prüfparameter zu definieren. Dies ist in Fällen sinnvoll, in denen trotz adäquater Kalzium- und Phosphorgehalte des Futters der Verdacht auf einen Phosphormangel besteht.Es wurden 34 Studien mit phytasesupplementierten Rationen (PHYT; Datensätze n = 110) und entsprechenden Kontrollrationen (CON; Datensätze n = 106) anhand der Parameter Kalzium- und Phosphoraufnahme, fäkale Kalzium- und Phosphorausscheidung und der jeweiligen scheinbaren Verdaulichkeit ausgewertet. Für beide Mineralien kam ein modifizierter Lucas-Test zur Anwendung, indem eine Regressionsberechnung von fäkaler Ausscheidung gegen Aufnahme (beides in mg/kg KMDer Lucas-Test zeigte keinen signifikanten Unterschied der fäkalen Kalziumausscheidung zwischen PHYT und CON (p = 0,29), während der in der Literatur vielfach beschriebene positive Effekt der Phytase auf die Phosphorverdaulichkeit sehr deutlich wurde (p0,01). Die fäkalen Kalzium/Phosphor-Quotienten aller Datensätze wurden berechnet und gruppiert, und zwar nach der Körpermasse (KM) der Tiere sowie der scheinbaren Phosphorverdaulichkeit (KM ≤ 30 kg: scheinbare Phosphorverdaulichkeit ≤ 60 % und60 %; KM30 kg: scheinbare Phosphorverdaulichkeit ≤ 40 % und40 %).Aus der Datenverteilung im Box Plot kann – unter der Voraussetzung eines Kalzium/Phosphor-Verhältnisses im Futter von ≥ 1,2 – bei einem fäkalen Kalzium/Phosphor-Quotienten von1,5 (für Schweine ≤ 30 kg KM) bzw.1,2 (für Schweine30 kg KM) auf eine hohe scheinbare Phosphorverdaulichkeit von über 60 % bzw. 40 % geschlossen werden.Werden in Kotproben Kalzium/Phosphor-Quotienten über diesen Schwellenwerten erreicht, ist eine schlechte Phosphorverdaulichkeit somit unwahrscheinlich. Bei fäkalen Kalzium/Phosphor-Quotienten unterhalb dieser „Grenzwerte“ ist keine Einschätzung der Phosphorverdaulichkeit möglich.

Calcium and phosphorus requirements for growing dogs can be calculated by different methods. The current standard feeding recommendations are based on experimental data derived from young giant breed puppies. In order to determine the absolute requirement, an extrapolation via metabolisable energy requirement is recommended. Another approach is to calculate the requirement factorially, taking into account the endogenous losses and the amount of calcium and phosphorus retained due to tissue accretion during growth as well as the expected availability of these nutrients. The working hypothesis was that both methods are valid and lead to comparable results in young puppies of a high mature body weight (BW). Yet, deviations for other age and mature BW groups were expected. Thus, the aim of the present study was to compare the results of both methods using exemplary puppies of different age and mature BW groups. The hypotheses could be verified for calcium. The extrapolated requirements overestimate the factorial requirements by up to 59.7% for puppies 6 months of age. In case of phosphorus requirement, the deviations between both methods are overall very high in all stages. Taking into account the potentially harmful effects of calcium and phosphorus excess, the feeding recommendations based on the extrapolation should be reconsidered.

Simple Summary The processing of feed items has an impact on their nutritive properties, e.g., differences in the degree of starch gelatinization between pelleted and extruded diets are apparent. In many species, including humans, it is known that this influences the digestion process on enzymatic and microbial levels, and thus the animals´ ability to utilize the diet. Laboratory animal diets are often marketed as identical products, e.g., a standard maintenance diet, which can be purchased in pelleted or extruded form. The hypothesis that there are differences in energy and nutrient digestibility among such products, even though they are claimed to be the same diet, was investigated. The results of the digestibility trials confirm the hypothesis. Additionally, they show that even among batches of the same laboratory rodent diet in the same form, standardization is not always achieved. Abstract Starch gelatinization is a major determinant of carbohydrate digestibility and varies with diet processing. Laboratory rodent diets are often marketed as identical, but are sold in different forms, regardless of the markedly higher starch gelatinization in extruded than in pelleted diets. Our hypothesis was that this would impact energy and nutrient digestibility in mice fed pellets or extrudate, respectively. Trial 1 showed that feeding C57BL/6 mice a standard maintenance diet in extruded form results in a significantly higher digestibility of organic matter, energy, and carbohydrates than the identical diet in pelleted form. The replication of the experiment, however, revealed a variation between batches of the same pelleted diet regarding starch and total dietary fiber contents. Given the significant differences in diet digestibility and the potential impacts of digestibility on nutrient utilization, the intestinal microbiome, and intermediary metabolism, trials performed with differently processed diets are not comparable. This might partly explain failures to reproduce results, especially in gastrointestinal or microbiome research. Considering this impact on experimental animals, the degree of starch gelatinization should be declared in the diet information for laboratory animal diets. The differences between batches of laboratory animal diets as observed in the pellets are not acceptable.

ZusammenfassungGegenstand und Ziel: Es wurde geprüft, wodurch die Etablierung der Ernährungsberatung in der Kleintierpraxis erschwert wird. Ferner werden Unterschiede im Problemlöseverhalten von Tierärzten bei der Ernährungsberatung dargestellt. Material und Methoden: Repräsentative Online-Befragung von 214 Tierärzten (weiblich/männlich) mittels eines standardisierten Fragebogens, Faktorenanalyse zur Typisierung der Tierärzte anhand einer Clusteranalyse. Ergebnisse: Mehr als 90% der Tierärzte waren der Ansicht, dass Fragen der Tierbesitzer zur Fütterung von Haustieren zugenommen haben, 41% der Tierärzte schätzten den Anteil ernährungsbedingter Krankheiten auf 20–30%. Gleichzeitig stimmten 70% der Aussage zu, dass die Ernährungsberatung im Praxisalltag vernachlässigt wird. Nach Angabe der Tierärzte setzen nur knapp 30% der Besitzer Ernährungsempfehlungen um. Mehr als 80% der Tierärzte nahmen an, dass Tierbesitzer falsche Angaben zur Fütterung der Tiere machen. In anderen sensiblen Punkten wie z. B. der häuslichen Situation wurden unrichtige Angaben dagegen auf unter 60% eingeschätzt. Etwa die Hälfte der Tierärzte fühlte sich bei der Ernährungsberatung nicht kompetent. Weniger als 50% liquidierten für diese Leistung. Eine Fortbildung zur Tierernährung besuchten nur 18% der Tierärzte. Die Clusteranalyse identifizierte fünf typische Verhaltensstrategien im Umgang mit der Ernährung, wobei vier davon auf einem eher geringen Stellenwert der Ernährung basierten. Einige der an Ernährungsfragen wenig interessierten Tierärzte überweisen an spezialisierte Kollegen (7,2%), andere wenden sich ratsuchend an die Futtermittelindustrie (28,2%), wieder andere behelfen sich mit kurzen kostenlosen Fütterungstipps (23,4%) und ein kleiner Teil verdrängt die Tierernährung weitgehend (13,4%). Es gibt aber auch eine Gruppe an der Tierernährung besonders interessierter Tierärzte (27,8%). Diese Gruppe war sich der Defizite bei den fachlichen und kommunikativen Kompetenzen am stärksten bewusst. Schlussfolgerung und praktische Relevanz: Für eine fundierte Ernährungsberatung in der Kleintierpraxis sind ein hoher Spezialisierungsgrad sowie praktikable Lösungen für die Anamneseerhebung und die Liquidierung notwendig.

ZusammenfassungAnamnese: Die Züchterin eines Wurfs Berner-Sennenhund-Welpen wünschte eine Überprüfung der von ihr erstellten BARF(Biologischartgerechte Rohfütterung)-Futterpläne für die verschiedenen Wachstumsphasen. Die Anamnese ergab, dass die Welpen zum Zeitpunkt der Anfrage für ihr Alter (6 Wochen) und ihr erwartetes Endgewicht untergewichtig waren. Die Mutterhündin gab fast keine Milch mehr. Rationsüberprüfung: Bei der Überprüfung der Futterpläne für die verschiedenen Wachstumsphasen wurden neben einer Unterversorgung mit Energie und zeitweise auch Protein insbesondere erhebliche Fehlversorgungen mit Kalzium und Phosphor festgestellt. Kalium, Natrium, Kupfer, Zink, Mangan, Jod sowie verschiedene Vitamine waren phasenweise oder über den gesamten durch die Futterpläne abgedeckten Zeitraum unzureichend in der Ration enthalten. Klinische Relevanz: Derartige Fehlversorgungen können bei Welpen, insbesondere solchen großwüchsiger Rassen, zu erheblichen Störungen des Wachstums und der Entwicklung führen. Daher erscheint eine sorgfältige Überprüfung selbst zusammengestellter Rationen (zur rohen oder gekochten Fütterung) durch spezialisierte Tierärzte, dringend geboten, um irreversible Schäden und dauerhafte Folgeerscheinungen für die Hunde zu vermeiden.

The nutritional status of 36 patients with equine pituitary pars intermedia dysfunction (PPID) under pergolide treatment was investigated.The body condi tion score (BCS) and feeding were determined at the beginning of the study and after 60 and 120 days. Sampled blood for control of pergolid therapy were used for insulin and glucose measurement. A standardized questionnaire regarding the symptoms of the disease, including hypertrichosis and weight change, was completed by the owners.The mean BCS (scale of 1 = cachexia to 9 = grossly obese) was 3.1 ± 0.8 (large horses 2.7 ± 0.8, ponies 3.5 ± 0.8). The mean energy requirement of the large horses was estimated to be 74 ± 10 MJ of metabolizable energy, but the intake amounted only to 65 ± 15 MJ. There was a significant correlation between the BCS and the estimated energy intake in percent of requirements in the large horses. The energy requirements of the ponies were generally met. The patients were fed a mean of 2.0 ± 0.7 meals of roughage per day (total roughage intake per day 0.2-2.1 kg/100 kg body weight) and a maximum of one meal of concentrates. Sixteen ponies and one large horse did not receive any concentrates, whereas five ponies and 14 horses were fed concentrates (mean amount for ponies 0.15 kg and for large horses 0.8 kg). The requirements for zinc, copper, selenium and vitamins A and E were not met in the majority of patients. Blood glucose levels were within the reference range in all samples, but insulin levels were elevated in seven animals at least at one sampling point. The serious underweight of some of the patients was not recognized as a problem by some of the owners.Owners of PPID patients need more guidance on body condition scoring, amount of feed, number of meals, and logistics of feeding to avoid malnutrition of their animals.

Objective: The worldwide prevalence of obesity has increased to 10% in men and 15% in women and is associated with severe comorbidities such as diabetes, cancer, and cardiovascular disease. Animal models of obesity are central to experimental studies of disease mechanisms and therapeutic strategies. Diet-induced obesity (DIO) models in rodents have provided important insights into the pathophysiology of obesity and, in most instances, are the first in line for exploratory pharmacology studies. To deepen the relevance towards translation to human patients, we established a corresponding DIO model in Göttingen minipigs (GM). Methods: Young adult female ovariectomized GM were fed a high-fat/high-energy diet for a period of 70 weeks. The ration was calculated to meet the requirements and maintain body weight (BW) of lean adult minipigs (L-GM group) or increased stepwise to achieve an obese state (DIO-GM group). Body composition, blood parameters and intravenous glucose tolerance were determined at regular intervals. A pilot chronic treatment trial with a GLP1 receptor agonist was conducted in DIO-GM. At the end of the study, the animals were necropsied and a biobank of selected tissues was established. Results: DIO-GM developed severe subcutaneous and visceral adiposity (body fat >50% of body mass vs. 22% in L-GM), increased plasma cholesterol, triglyceride, and free fatty acid levels, insulin resistance (HOMA-IR >5 vs. 2 in L-GM), impaired glucose tolerance and increased heart rate when resting and active. However, fasting glucose concentrations stayed within normal range throughout the study. Treatment with a long-acting GLP1 receptor agonist revealed substantial reduction of food intake and body weight within four weeks, with increased drug sensitivity relative to observations in other DIO animal models. Extensive adipose tissue inflammation and adipocyte necrosis was observed in visceral, but not subcutaneous, adipose tissue of DIO-GM. Conclusions: The Munich DIO-GM model resembles hallmarks of the human metabolic syndrome with extensive adipose tissue inflammation and adipocyte necrosis reported for the first time. DIO-GM may be used for evaluating novel treatments of obesity and associated comorbidities. They may help to identify triggers and mechanisms of fat tissue inflammation and mechanisms preventing complete metabolic decompensation despite morbid obesity. Keywords: Pig, High fat diet, Obesity, Diabetes, Metabolic syndrome, Adipose tissue inflammation

A retrospective analysis of the metabolizable energy (ME) intake of privately owned pet cats from the authors' nutrition consultation practice (years 2007-2011) was carried out to test whether current recommendations are suitable for pet cats. Data of 80 adult cats (median age: 9.0 years, median deviation from ideal weight: +22.5%, majority neutered) at maintenance were available. Six percentage of the cats were healthy and the others were affected by various chronic diseases. A standardized questionnaire was used, cat owners weighed cat and food. For ration calculation, the software Diet Check Munich(™) was used (ME prediction according to National Research Council, 2006: Nutrient Requirements of Dogs and Cats. National Academy Press, Washington, DC). Data were analysed for the factors deviation from ideal weight, breed, age, gender, disease and type of feeding [prepared food (dry, wet) vs. home-made]. Over- or underweight were defined as ≥15% deviation from ideal body weight (BW) according to Kienzle and Moik (British Journal of Nutrition 2011, 106, Suppl 1: S113). Cat owner's estimation of ideal BW was higher than literature data from Kienzle and Moik (2011). Based on literature data, 26.3% of the pet cats were normal weight, 63.7% overweight and 10% underweight. The mean ME intake of all adult cats amounted to 0.40 ± 0.14 MJ/kg actual BW(0.67) (n = 80). When the data were analysed according to normal, over- and underweight, there was a significant effect with normal weight cats eating 0.46 MJ/kg BW(0.67) . Underweight cats ate even more (0.49 MJ/kg BW(0.67) ), whereas overweight cats ate considerably less (0.36 MJ/kg BW(0.67) ). The other factors had no influence on ME intake of adult cats.

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 23–31 hr, which is of a magnitude also recorded in horses; these did not differ for solute or small particle (

To investigate the impact of a selective reduction in dietary phosphorus (P) supply on healthy growing dogs, a total of 23 Beagles and 30 Foxhound crossbreds (FBI) were used in a feeding trial between 6 and 24 weeks of age. Sixteen Beagles and 19 FBI were fed with selectively reduced P concentrations (low phosphorus, LP). The remaining puppies received a completely balanced control diet (CON). With these diets, the P supply in the Beagles at the age of 12 weeks added up to 2.5 +/- 0.6 (LP) and 9.8 +/- 1.4 g P/kg DM (CON), and in the FBI 4.3 +/- 0.9 (LP) and 13.0 +/- 1.6 g P/kg DM (CON). Therefore, the LP Beagles received an average of 33 +/- 11% of the recommended daily allowances (RDA) of P, the LP FBI 41 +/- 11%. The calcium (Ca) concentration stayed unaltered and led to a Ca/P ratio above the recommended range of 1.3/1 to 2/1. The apparent digestibility (aD) of phosphorus was reduced in the LP Beagle;otherwise, the aD of both minerals was not affected by the P concentration of the diet. The renal excretion of P was reduced to zero in both LP groups while the renal calcium excretion increased significantly. Several of the puppies from both breeds showed impaired appetite, growth, skin and fur quality, and a few also clinically showed relevant signs of a disturbed musculoskeletal system after the LP feeding. A rapid loss of muscle strength and posture within hours led to severe deviation of the limb axis with hyperflexion of the joints but no radiological aberrations or signs of pain. Immediate transition of affected puppies to a balanced diet with sufficient phosphorus resulted in a complete recovery of the puppies in less than one month. The results demonstrate the importance of an adequate P supply on the healthy development of growing dogs.

Summary According to a previous meta-analysis, adult dogs do not notably increase calcium absorption from the gastrointestinal tract when calcium intake is decreased. This results in a negative calcium balance even with a moderate calcium reduction. In this study we wanted to verify (i) whether a negative calcium balance occurs at a calcium intake equivalent to NRC (2006) (Nutrient requirements of dogs and cats, 2006, The National Academies Press, Washington, DC) minimal requirements, and if so (ii) whether the negative calcium balance will persist for up to 6 months on a low-calcium diet. After a pre-feeding period of at least 18 weeks with calcium intake slightly exceeding maintenance requirements (200 mg/kg body weight0.75), 12 dogs (6 Beagles, 6 Foxhound crossbreds) were fed a low-calcium diet for 28 weeks. One dog was removed from the trial for reasons unrelated to the study at week 23. Calcium intake amounted to 60 mg/kg body weight0.75 corresponding to the minimal requirement for maintenance in dogs (NRC, 2006 (Nutrient requirements of dogs and cats, 2006, The National Academies Press, Washington, DC)). Digestion trials were carried out at week 7, 14, 21 and 28 of the low calcium feeding period. At these time points, and at week 18 of the pre-trial, blood samples were taken and analysed for calcium, ionised calcium, phosphorus, parathyroid hormone, vitamin D, serum crosslaps and bone alkaline phosphatase. Apparent calcium digestibility was negative throughout the study, suggesting a negative calcium balance. There was no systematic decrease in faecal calcium excretion. Serum calcium, ionised calcium and phosphorus remained within the reference range. Serum crosslaps increased continuously from baseline to week 28 of trial, with averages increasing from 0.102 ng/ml to 0.279 ng/ml, suggesting osteoclastic activity, indicative of calcium mobilisation from the skeleton. The study supports the theory of a lack of adaptation of intestinal calcium absorption from diets with relatively low calcium content in dogs. This agrees with clinical findings in dogs eating low-calcium diet.

The recommendations for the Ca supply for maintenance of dogs have been reduced by about 75 % in the last decades. An important factor for Ca requirements is faecal Ca losses. In previous studies with experimental diets faecal Ca losses depended on Ca intake and on faecal DM excretion. A predictive equation for faecal Ca losses in mg/kg body weight (BW) developed in a fibre model is: faecal losses = −33·8 + (13·6 faecal DM excretion (g/kg BW)) + (0·78 Ca intake (mg/kg BW)). The present study aimed at testing this equation in pet food with material from trials carried out for other purposes. Digestion trials with twenty-five dry and fifteen moist foods (326 observations in total) were evaluated retrospectively. Faecal DM excretion and faecal Ca losses were significantly correlated (r2 0·86; P r2 0·87; P et al. The data from the previous fibre model study could be transferred to prepared moist and dry dog food. Faecal DM excretion has a considerable impact on faecal Ca losses in a practical feeding situation. In conclusion, Ca requirements for maintenance may vary with food DM intake and digestibility.

Objectives Truly ketogenic rodent diets are low in carbohydrates but also low in protein. The aim of this study was to differentiate effects of ketosis, low carbohydrate (LC) and/or low-protein intake on energy and nitrogen metabolism. Methods We studied the nitrogen balance of rats fed LC diets with varying protein contents: LC diets consisted of 75/10, 65/20 and 55/30 percent of fat to protein (dry matter), respectively, and were iso-energetically pair-fed to a control (chow) diet to 12-wk-old male Wistar rats (n = 6 per diet). Previous studies demonstrated only LC75/10 was truly ketogenic. Food, fecal, and urine samples, as well as carcasses were collected and analyzed for heat of combustion and nitrogen (Kjeldahl method). Blood samples were analyzed for plasma protein, albumin, and triacylglycerol. Results All LC groups displayed less body weight gain, and the degree of reduction was inversely related to digestible crude protein intake (daily weight gain compared with chow: LC75/10: −50%; LC55/30: −20%). Nitrogen excretion by urine was related to digestible protein intake (chow: 0.23 ± 0.02 g nitrogen/d; LC75/10: 0.05 ± 0.01 g nitrogen/d). Renal energy excretion was closely associated with intake of digestible crude protein ( r = 0.697) and renal nitrogen excretion ( r = 0.769). Energy-to-nitrogen ratio in urine was nearly doubled with LC75/10 compared with all other groups. Total body protein was highest with chow and lowest with LC75/10. Rats fed with LC75/10 displayed features of protein deficiency (reduced growth and nitrogen balance, hypoproteinemia, depletion of body protein, and increased body and liver fat), whereas the effects with the non-ketogenic diets LC65/20 and LC55/30 were less pronounced. Conclusion These results suggest that truly ketogenic LC diets in growing rats are LC diets that are also deficient in protein for growth.