SummaryA meta-analysis was conducted to understand quantitative aspects of calcium (Ca) and phosphorus (P) absorption in adult dogs and cats. 34 studies in dogs and 14 studies in cats met the criteria for inclusion in the meta-analysis. Intake and faecal excretion values of Ca and P were subjected to a modified Lucas test and subsequent regression analyses. According to the current scientific consensus, Ca true digestibility (absorption) should increase at low Ca intake and decrease at high Ca intake. If true, this should result in a nonlinear relationship between the percentage of Ca excreted and dietary Ca intake. The present metaanalysis showed a highly significant linear relationship (p < 0.0001) between Ca intake and Ca excretion suggesting a lack of systematic quantitative adaptation in true Ca digestibility. This finding suggests either that the time period covered by standard digestion trials is too short to induce adaptation mechanisms or that dogs and cats at maintenance will not efficiently alter quantitative Ca absorption percentage according to the amount ingested. If the latter is true, a dietary Ca supply differing greatly from the recommended dietary intake might impair the health of cats and dogs when fed long term. The data plots for P intake and faecal excretion were less uniform suggesting other factors not just dietary intake influence faecal P excretion. In adult cats, the dietary Ca:P ratio strongly influenced the true digestibility of P, whereas this effect was less marked in adult dogs. Faecal P excretion was significantly correlated to faecal Ca excretion in both species (p < 0.0001), and surprisingly, the level of P intake did not appear to be an important determinant of true digestibility of 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.

No abstract

ObjectiveThe 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).MethodsYoung 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.ResultsDIO-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.ConclusionsThe 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.

SummaryTo 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. K E Y W O R D Sbone turnover, calcium, comparative, digestibility, phosphorus | INTRODUCTIONIn a meta-analysis on calcium (Ca) and phosphorus (P) intake vs. faecal excretion in dogs and cats, Mack, Alexander, Morris, Dobenecker, and Kienzle (2015) observed a close linear relationship between faecal Ca and P excretion (R² = .94 in dogs), regardless of the Ca/P ratio and the source of Ca and P in the food. A possible explanation could be the formation of insoluble Ca/P complexes. Whether similar close relationships can be observed in mammalian species other than domestic carnivores has, to our knowledge, not been investigated. A comparative investigation of the relationship between faecal Ca and P excretion may help to understand differences and similarities between species. One hypothesis is that the regression equation of faecal Ca and P excretion reflects the intestinal formation of insoluble Ca/P complexes. In chickens, a constant ratio of intestinal Ca/P has been found (Hurwitz & Bar, 1971) and interpreted as the formation of insoluble Ca 3 (PO 4 ) 2 (Humer, Schwarz, & Schedle, 2015). The atomic weight ratio of Ca to P in this complex is 2 to 1, which should be represented in the regression equation of faecal Ca and P excretion if the complex actually is a major determinant of mineral excretion.Another assumption is that microbial activity in the gastrointestina...

The effects of cellulose added in three levels (7, 15 and 20% crude fibre in dry matter) to three different basal diets (a high fat diet, a high starch diet with raw starch and a high starch diet with cooked starch) on apparent digestibility were investigated in eight adult dogs. Cellulose had little effect on the apparent digestibility of fat. In the high fat diet there was no significant decrease, not even at the highest cellulose level (98.3% compared with 98.1% in the basal high fat diet). In the cooked starch diets, fat digestibility decreased from 95.1% in the basal cooked starch diet to 93.8% at the highest cellulose level. In the raw starch diets, digestibility did not decrease with increasing cellulose levels. The apparent digestibility of crude protein was considerably decreased by cellulose in all diets. Starch also decreased protein digestibility and the effects of cellulose and starch appeared to be additive (high fat diet decrease of protein digestibility from 86.7 to 83.5%, cooked starch from 81.6 to 78.6%, raw starch from 79.0 to 70.8%, basal diets to highest cellulose levels, respectively). The apparent digestibility of nitrogen-free extract decreased from 93.9% in the basal cooked starch diet to 84.5% at the highest cellulose level. The figures for the raw starch diets were similar (decrease from 93.4 to 85.9%). Cellulose decreased the apparent digestibility of energy in all diets. This decrease was more marked in the high starch diets (cooked starch decrease from 89.1 to 69.6%, raw starch from 88.9 to 70.2%) than in the high fat diet (decrease from 90.1 to 76.1%). An evaluation of previous data showed that in general fibre has a higher impact on the apparent digestibility of energy in high carbohydrate diets than in low carbohydrate diets. The apparent digestibility of potassium, sodium and chloride was impaired by cellulose. The apparent digestibility of these minerals tended to be lower in the high starch diets, especially in the raw starch diet, and the effect of cellulose was usually more marked in those diets.

No abstract

SummaryA post hoc analysis of the metabolizable energy (ME) intake of privately owned pet dogs from the authors' nutrition consultation practice (Years 2007(Years -2011 was carried out to identify if current ME recommendations are suitable for pet dogs. Data on 586 adult dogs were available (median age 5.5, median deviation from ideal weight 0.0), 55 of them were healthy; the others had various diseases. For ration calculation, a standardized questionnaire and the software diet-check Munich TM was used. ME was predicted according to NRC (2006). Data were evaluated for the factors disease, breed, size, age, gender and type of feeding. The mean ME intake of all adult dogs amounted to 0.410 AE 0.121 MJ/kg metabolic body weight (BW 0.75 ) (n = 586). There was no effect of size and disease. . The mean maintenance energy requirements of pet dogs are similar to that of kennel dogs which do not exercise very much. These results suggest that opportunity and stimulus to exercise provided for pet dogs are lower than for kennel dogs. Lower activity in pet dogs may reduce part of potential effects of breed, medical history and age groups.