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

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 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 x 12 hr at daytime and afterwards 3 x 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;r(2) = .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

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

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

A new protein evaluation system for horse feed from literature data

Few data on apparent pre-caecal digestibility (APCD) of crude protein (CP) and particularly amino acids (AA) are available from studies with horses. Protein bound in cell walls (i.e. neutral detergent insoluble CP (NDICP)) is unlikely to be decomposed by digestive enzymes in the small intestine. In contrast the corresponding analytical fraction of neutral detergent soluble CP (NDSCP) (NDSCP = CP-NDICP) is likely to be available for auto-enzymatic digestion. A literature analysis on the relationship between NDICP/NDSCP and pre-caecal indigestible/digestible CP was carried out. There was a strong positive relationship between NDICP and pre-caecal indigestible CP, which suggests that NDICP can be used to estimate the part of protein that is not available for digestion in the small intestine. There was also a correlation between NDSCP and pre-caecal digestible protein. The slope of the linear regression line between NDICP and pre-caecal digestible CP was 0.9, suggesting an APCD of NDSCP of 90 %. Thus pre-caecal digestible CP may be predicted by multiplying NDSCP by 0.9. Because the literature identifies a similar AA profile in NDICP and NDSCP within a given feed the presented concept may preliminarily be transferred to AA. The proposed system can at any time be adapted to the scientific progress without altering its structure. Such adaptations would be necessary particularly when new knowledge exist on the distribution of AA onto NDICP/NDSCP, the APCD of individual AA from NDSCP, and the impact of feed processing and chewing on particle sizes and protein digestibility

A new protein evaluation system for horse feed from literature data

Few data on apparent pre-caecal digestibility (APCD) of crude protein (CP) and particularly amino acids (AA) are available from studies with horses. Protein bound in cell walls (i.e. neutral detergent insoluble CP (NDICP)) is unlikely to be decomposed by digestive enzymes in the small intestine. In contrast the corresponding analytical fraction of neutral detergent soluble CP (NDSCP) (NDSCP = CP-NDICP) is likely to be available for auto-enzymatic digestion. A literature analysis on the relationship between NDICP/NDSCP and pre-caecal indigestible/digestible CP was carried out. There was a strong positive relationship between NDICP and pre-caecal indigestible CP, which suggests that NDICP can be used to estimate the part of protein that is not available for digestion in the small intestine. There was also a correlation between NDSCP and pre-caecal digestible protein. The slope of the linear regression line between NDICP and pre-caecal digestible CP was 0.9, suggesting an APCD of NDSCP of 90 %. Thus pre-caecal digestible CP may be predicted by multiplying NDSCP by 0.9. Because the literature identifies a similar AA profile in NDICP and NDSCP within a given feed the presented concept may preliminarily be transferred to AA. The proposed system can at any time be adapted to the scientific progress without altering its structure. Such adaptations would be necessary particularly when new knowledge exist on the distribution of AA onto NDICP/NDSCP, the APCD of individual AA from NDSCP, and the impact of feed processing and chewing on particle sizes and protein digestibility

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

Simple Summary Starch is the main carbohydrate source in most lab mouse diets. Its properties are influenced by feed processing. This determines how easily accessible it is to enzymatic digestion in the gastrointestinal tract of animals. In previous studies we have shown that there are differences between pelleted and extruded forms of a maintenance diet fed to mice regarding digestibility and microbiome. To complement these findings, the present study presents a morphological study of the starch particles throughout the passage along the gastrointestinal tract of C57BL/6J mice fed either pellets or extrudate. Samples were stained with Lugol's iodine and examined via stereomicroscope and scanning electron microscope. Starch granules in the pelleted diet are mostly intact and compact, thus autoenzymatic digestion in the small intestine is less efficient than in the more accessible starch granules from the extruded diet. For both diet forms, starch accumulation in the caecum was observed, suggesting selective retention of praecaecally undigested starch for microbial fermentation. These findings allow for unique insights in murine starch digestion that are important to understand the digestive physiology of this species. 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

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