Effects of dietary phosphates from organic and inorganic sources on parameters of phosphorus homeostasis in healthy adult dogs

Background The impact of dietary phosphorus (P) excess, especially on renal and cardiovascular health, has been investigated in several species, but little is known in dogs. Objective The aim of this study was to examine effects of different P sources on concentration and postprandial kinetics of selected parameters of P homeostasis in dogs. Methods Eight beagles received one control diet (P 0.5% dry matter [DM]) and three high P diets (poultry meal, NaH2PO4, and KH2PO4; P 1.7% DM) for 18d. Urine samples were collected pre- and postprandially while faeces were collected quantitatively for 5d and analysed for minerals. On day 18, blood was sampled 1h pre- and 0.5, 1, 1.5, 2, 3, 5 and 7h postprandially. Results Pi (KH2PO4, NaH2PO4) but not organic P caused an increased apparent P digestibility and significantly influenced kinetics of serum FGF23, parathyroid hormone, P, CrossLaps and bonespecific alkaline phosphatase, demonstrating a disrupted calcium (Ca) and P homeostasis with potential harm for renal, cardiovascular and skeletal health. Conclusions Results of feeding Pi to dogs indicate distinct disturbances of Ca and P metabolism, in contrast to organic sources. The use of Pi in food can therefore not be considered as safe. Further research, especially on dose and long-term effects, is warranted

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 +/- L2 g DM/kg BW). Mineral supplements were added separately for identical Ca and P supply independent of DM intake (Ca 226 and P similar to 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 arid (ii) Ca requirements may be affected by DM intake arid digestibility

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

SIMPLE SUMMARY: The vast majority of pet food products on the market contain the major mineral phosphorus in amounts exceeding the recommended daily allowance. A considerable amount of phosphorus in such products is highly water-soluble and bioavailable. Even though a sufficient supply of phosphorus is important for the body, an excessive intake can be harmful, especially in renal patients but also healthy individuals. This study investigated the effects of an excessive intake of organic phosphate sources (e.g., meat and bone meal) and inorganic phosphate salts compared with a balanced control diet without inorganic phosphates on factors of the body’s phosphorus regulatory system in healthy, adult beagle dogs. Most inorganic phosphates but not the organic phosphorus sources caused significant changes in these regulatory factors compared with the control diet. We conclude that the use of these inorganic phosphates in pet food is potentially harmful and should be restricted. ABSTRACT: 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

Effect of a high phophorus diet on indicators of renal health in cats

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

Factorial calculation of calcium and phosphorus requirements of growing dogs

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

Bioactive collagen peptides as supplement for horses with osteoarthritis

Introduction: Osteoarthritis (OA) is a degenerative joint disease characterised by progressive destruction of cartilage and bone with a high prevalence in horses. It causes pain, lameness and functional disability and is therefore economically important. Existing treatment options are limited and often based on pain reduction. Research on Bioactive Collagen Peptides® (BCP) demonstrated its stimulating effect on cartilage tissue in pre-clinical in vitro and in vivo studies, the latter ones done in a validated OA animal model on Str/ort-mice. The aim of this pilot study was to test if oral BCP supplementation has the potency to mend OA in horses. Animals, materials and methods: 38 privately owned horses with mild to moderate OA were available for the two-centred study. In one centre 18 of these patients (6±3 years old; 519±100kg BW) received either 25g (n=6) or 50g (n=12) BCP#/day orally for 12 weeks. In the second centre 20 horses (18±4; 413±94kg BW) received either a placebo (Con; maltodextrine; n=10) or 25g BCP/day. The attending veterinarian performed an orthopaedic examination, a flexion test and evaluated the degree of lameness, rotation pain, step length and arc of flight during trot (8 parameters) at the beginning and after 6 and 12 weeks of the trial. The owners answered a weekly questionnaire about their perception of lameness, mobility and the horses’ willingness to move. Statistical significance of the differences between the 3 groups (25g, 50g, Con) were tested calculating the effect size (Cohen r) for the evaluation of veterinarians and owners as well as the p values (Wilcoxon, Mann-Whitney-U-test). Results: Data of all 38 horses from both centres were evaluated together. As expected, no adverse effects have been observed. In the 50g group in 6/8 parameters a strong effect (Cohen r>0.5) was detected between beginning and end of the trial, with 2 parameters (lameness, flexion pain) significantly improved already after 6 weeks. In the 25g group a moderate effect (Cohen r=0.3-0.5) was seen in 6 parameters, with 3 parameters improved already after 6 weeks. The evaluation of the owners’ answers revealed a strong effect for the factors mobility and willingness to move (Cohen r 0.69 and 0.62, respectively) and a moderate effect (Cohen r=0.49) for the development of lameness in the 50g group when compared to the placebo treatment (group Con). The 25g dosage showed a moderate improvement (r=0.41) of the lameness. All these differences in the BCP groups were of statistically significance when compared with the placebo treatment demonstrated by the Mann-Whitney-U-test. Discussion: This study revealed promising effects of the safe oral BCP supplementation on symptoms of OA in horses already after the relatively short period of 3 months. The higher dosage of 50g/day had superior impact on the skeletal health of the osteoarthritic horses. Further long-term investigations on BCP efficacy in horses with OA, preferably in blinded and placebo controlled studies, are needed. #Petagile® GELITA AG, German

Comparison of Veterinary Nutrition Exam Results After Classroom or Virtual Teaching During the COVID-19 Pandemic at a German University

Due to the COVID-19 pandemic, university teaching had to be kept up in spite of severe contact restrictions. Virtual teaching of animal nutrition was implemented at the Veterinary Faculty of the Ludwig-Maximilians-Universität (LMU) München, Germany, for both lectures and practical courses. Live online classes were held via Zoom®, and recordings were accessible afterwards. Animal nutrition is taught in the 5th and 6th term of the veterinary studies, followed by an oral state exam about subjects from both terms. In this study, the success of classroom vs. virtual teaching in veterinary animal nutrition was evaluated by comparison of exam results. Two exam cohorts (2019, before the pandemic; 2020, with one term of virtual teaching during the pandemic) were evaluated. The results indicated no significant difference of teaching method on the grades. However, there was a significantly higher probability of students not taking or failing the exam in the 2020 exam cohort, suggesting a general effect of the pandemic on the students. Additionally, two surveys were distributed among the students during summer term 2020 and winter term 2020/21, when virtual teaching due to the pandemic had been implemented for the first time. The survey results provide insights into the students' view of benefits and problems of virtual teaching in animal nutrition at the LMU. The majority was in favor of the live online format for lectures and courses in computed-based ration calculation, whilst feedstuff demonstrations were preferred in classroom setting

Effect of mitratapide on body composition, body measurements and glucose tolerance in obese Beagles

The objective of this study was to confirm that weight loss after treatment with mitratapide (Yarvitan®) is loss of adipose tissue. Obese dogs were treated with the recommended treatment schedule of mitratapide. Dual-energy X-ray absorptiometry (DEXA) was done before and after the treatment schedule. Body weight, feed consumption and pelvic circumference were recorded and a glucose tolerance test was performed. Dual-energy X-ray absorptiometry measurements showed an impressive loss of fat tissue, corresponding to a mean loss of approximately 41.6% of the body fat mass recorded before treatment. After treatment with mitratapide, the mean body fat percentage had returned within the normal range. At the end of the study, the dogs had lost on average 14.2% of their body weight and 15.2% of their pelvic circumference compared to baseline. The results also suggest that losing weight with mitratapide might help to reverse insulin resistance

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