Metabolisable energy content in canine and feline foods is best predicted by the NRC2006 equation

Accuracy of Predictive Equations for Metabolizable Energy Compared to Energy Content of Foods for Dogs and Cats Estimated by In Vivo Methods in Brazil

In small animal nutrition, the caloric content of a diet is expressed as metabolizable energy (ME). The gold standard method for determining this variable is through feeding trials with the target species. However, the high cost and intricacy of this assay lead to the use of indirect estimation methods. The aim of this study was to analyze the main equations employed for estimating ME and compare them with the results of in vivo tests. In total, 451 pet food products in Brazil were evaluated. The ME values were determined via the bromatological values available on labels. The data were analyzed using SAS, and Student's t test was used with a significance of 5%. For all predictive equations, there was a non-conformity between their results and those obtained by in vivo methods. Thus, the prediction equations are only accurate when the exact values of food composition are used, which is hardly applicable since veterinarians and animal owners only have access to the information provided on the labels. Nonetheless, the Atwater system equation proved to be the most reliable for estimating ME, showing the smallest disparity among the evaluated methods. The overall differences between in vivo results and ME estimation with the Atwater system amounted to 3.59% for dry cat foods and -1.94% for dry dog foods. Moreover, although it was also the most accurate for wet foods, the differences were substantially greater (11.99% for cat foods and 8.25% for dog foods). These findings highlight the need for further research to refine ME estimation, which could contribute to improved pet food formulation and help reduce cases of malnutrition in dogs and cats.

Correction: Metabolisable energy content in canine and feline foods is best predicted by the NRC2006 equation

[This corrects the article DOI: 10.1371/journal.pone.0223099.].

Nutritional evaluation of new alternative types of dog foods including raw and cooked homemade-style diets

BACKGROUND

New alternative types of pet foods such as raw and cooked homemade-style diets containing human food ingredients have been introduced due to a trend of pet humanization and diversification of consumer needs.

OBJECTIVES

To evaluate nutritional adequacy of new alternative types of dog foods containing human food ingredients as maintenance diets for dogs.

METHODS

Eleven homemade-style foods for adult dogs were purchased from online channel in Korea and analyzed to evaluate nutritional adequacy for adult dogs. Nutrients analyzed included crude protein, amino acids, crude fat, fatty acids, and minerals.

RESULTS

Crude protein and amino acids in all products satisfied Association of American Feed Control Officials (AAFCO) requirements. Crude fat in one of 11 products did not meet AAFCO requirements. The most deficient minerals were selenium (10 of 11, 90.9%), copper (five of 11, 45.5%), zinc (five of 11, 45.5%), potassium (three of 11, 27.3%), calcium (three of 11, 27.3%), iron (two of 11, 18.2%), and magnesium (one of 11, 9.1%). Six products were not in the range of the recommended Ca:P ratio in AAFCO dog food maintenance nutrient profiles.

CONCLUSIONS

This study performed nutritional evaluation of raw and cooked homemade-style foods as maintenance diets for adult dogs. Some nutritional inadequacies were observed including some minerals, Ca:P ratio, and omega-6:omega-3 fatty acid ratio, although three products (26.2%) satisfied the AAFCO standard except selenium. Overall, the data suggest a need for accurate nutritional adequacy statement for consumers based on proper methods to validate the formula.

The threshold value for identifying insulin resistance (HOMA-IR) in an admixed adolescent population: A hyperglycemic clamp validated study

Objective

To validate the homeostasis model assessment (HOMA) of insulin resistance (IR) as a surrogate to the hyperglycemic clamp to measure IR in both pubertal and postpubertal adolescents, and determine the HOMA-IR cutoff values for detecting IR in both pubertal stages.

Subjects and methods

The study sample comprised 80 adolescents of both sexes (aged 10-18 years; 37 pubertal), in which IR was assessed with the HOMA-IR and the hyperglycemic clamp.

Results

In the multivariable linear regression analysis, adjusted for sex, age, and waist circumference, the HOMA-IR was independently and negatively associated with the clamp-derived insulin sensitivity index in both pubertal (unstandardized coefficient - B = -0.087, 95% confidence interval [CI] = -0.135 to -0.040) and postpubertal (B = -0.101, 95% CI, -0.145 to -0.058) adolescents. Bland-Altman plots showed agreement between the predicted insulin sensitivity index and measured clamp-derived insulin sensitivity index in both pubertal stages (mean =-0.00 for pubertal and postpubertal); all P > 0.05. The HOMA-IR showed a good discriminatory power for detecting IR with an area under the receiver operator characteristic curve of 0.870 (95% CI, 0.718-0.957) in pubertal and 0.861 (95% CI, 0.721-0.947) in postpubertal adolescents; all P < 0.001. The optimal cutoff values of the HOMA-IR for detecting IR were > 3.22 (sensitivity, 85.7; 95% CI, 57.2-98.2; specificity, 82.6; 95% CI, 61.2-95.0) for pubertal and > 2.91 (sensitivity, 63.6; 95% CI, 30.8-89.1, specificity, 93.7; 95%CI, 79.2-99.2) for postpubertal adolescents.

Conclusion

The threshold value of the HOMA-IR for identifying insulin resistance was > 3.22 for pubertal and > 2.91 for postpubertal adolescents.

Predictive equations for dietary energy are improved when independently developed for dry and wet food which could benefit both the pet and the environment

Introduction

Measuring energy availability through metabolizable energy feeding studies is the "gold standard" for establishing metabolizable energy concentration. However, predictive equations are often used to estimate metabolizable energy in dog and cat pet foods. The goal of this work was to evaluate the prediction of energy density and compare those predictions to each other and the energy needs of the individual pets.

Methods

Feeding studies used 397 adult dogs and 527 adult cats on 1,028 canine and 847 feline foods. Individual pet results for the estimate of metabolizable energy density were used as outcome variables. Prediction equations were generated from the new data and compared to previously published equations.

Results and discussion

On average the dogs consumed 747 kilocalories (kcals) per day (SD = 198.7) while cats consumed 234 kcals per day (SD = 53.6). The difference between the average prediction of energy density and the measured metabolizable energy varied from the modified Atwater prediction 4.5%, 3.4% (NRC equations), 1.2% (Hall equations) to the new equations calculated from these data at 0.5%. The average absolute values of the differences between measured and predicted estimates in pet foods (dry and canned, dog and cat) are: 6.7% (modified Atwater), 5.1% (NRC equations), 3.5% (Hall equations) and 3.2% (new equations). All of these estimates resulted in significantly less variation in the estimate of the food expected to be consumed than the observed variation associated with actual pet consumption to maintain body weight. When expressed as a ratio of energy consumed to metabolic body weight (weight in kilograms^3/4) the within species variation in energy consumed to maintain weight was still high as compared to the energy density estimates variance from measured metabolizable energy. The amount of food offered as the central point in a feeding guide, based on the prediction equations, would on average result in an average variance between 8.2% error in the worst case estimate (feline dry using modified Atwater estimates) and approximately 2.7% (the new equation for dry dog food). All predictions had relatively small differences in calculating food consumed when compared to the differences associated with the variation in normal energy demand.

Apparent total tract nutrient digestibility and metabolizable energy estimation in commercial fresh and extruded dry kibble dog foods

Commercial fresh cooked foods have started gaining popularity among American dog owners in recent years. However, nutrient digestibility and the estimation of metabolizable energy (ME) of commercial fresh dog foods remain inadequately understood, even though both measures are critical to provide the intended calories for the target animal. In this preliminary study, different cohorts of normal-weight dogs were fed one of five test diets of comparable macronutrient composition: a chicken-based extruded dry kibble diet (n = 12), and chicken- (n = 12), beef- (n = 6), pork- (n = 6), or turkey-based fresh food (n = 6) for 10 d. Daily food intake and fecal characteristics were recorded, and fecal samples were collected for nutrient analysis. Despite comparable dry matter (DM) and caloric intakes between the two chicken-based diets, the fresh diet led to lower defecation frequency (1.2 ± 0.2 vs. 1.7 ± 0.5 times/d, adjusted P < 0.001), lower fecal DM (24 ± 8 vs. 47 ± 10 g/d, adjusted P < 0.001), and lower fecal calories (92 ± 31 vs. 189 ± 43 kcal/d, adjusted P < 0.001) than the kibble diet. The apparent total tract digestibility of DM, protein, fat, nitrogen-free extract, and calories of the kibble diet were all significantly lower than any of the fresh diets (adjusted P < 0.001 for all). Measured ME per food DM in all of the fresh diets, except the pork-based recipe, was significantly higher than that of the kibble diet (adjusted P < 0.001 for all). For the kibble diet, the modified Atwater calculation underestimated the ME and the NRC 2006 calculation was the most accurate predictor of ME. The standard Atwater calculation performed best for the two fresh diets that had the highest fat content (chicken, beef) and the NRC 2006 calculation performed best for the fresh diet that had the highest protein content (pork). ME of the turkey-based diet was equally overestimated and underestimated with the standard Atwater and NRC 2006 methods, respectively. We propose that commercial and home-prepared fresh diets should be assessed using standard Atwater factors as commonly done in human nutrition, or preferably for commercial products, by direct measurement in conforming feeding trials.

Relationship between a plant-based 'vegan' pet food and clinical manifestation of multiple nutrient deficiencies in two cats

A topical subject in human nutrition is the steadily growing number of people choosing to limit or completely avoid all animal-derived food products either for moral dilemma, health concerns or both. To meet people's will of applying their dietary choices to their domestic animals, the pet food industry answered by launching on the market some plant-based diets. This leads to concerns about whether these diets are adequately formulated to satisfy the target species nutritional requirements, especially for cats which are still considered strict carnivores. This case report follows a 2-year-old male neutered Main Coon and a 1-year-old female spayed Domestic Shorthair cat, presented to the nutrition service of the University of Toulouse, France. Reason for consultation was lethargy with in anamnesis a recent dietary transition to a plant-based pet food. Dysorexia, lethargy and muscle waste were present at first consultation. Progressive weight loss developed during follow-ups. A macrocytic, non-regenerative anaemia with serum folates below reference were the main clinical features. Analysis of pet food showed multiple nutrients below minimum recommendation at the average daily intake of both cats. Folic acid supplementation improved dysorexia, and subsequent reintroduction of animal-derived ingredients in the diet restored appetite, weight and a normal mentation in both cases.

Managing Feline Idiopathic Hypercalcemia With Chia Seeds (Salvia hispanica L.): A Case Series

Background: We describe for the first time the use of chia seeds (Salvia hispanica L.) as a non-pharmacological solution in managing feline idiopathic hypercalcemia when dietary change alone fails. Case Summary: Over a 2-year period of time, three female spayed, middle-aged, Domestic Shorthair cats were diagnosed with idiopathic hypercalcemia. Reason for consultation were lethargy and dysorexia, with a single episode of vomiting described in one cat and dysuria in another. Thorough diagnostic work-up included complete blood count, serum biochemistry, urinalysis, ionized calcium, calcemic hormones, parathyroid hormone-related protein, and imaging of chest and abdomen. Based on different nutritional reasons, each cat was switched to a different high-moisture pet food as first-step in managing the disorder: a high-fiber diet, a diet formulated for chronic kidney disease management and a diet designed to prevent calcium oxalate urolithiasis. In the three cats, 6 weeks of dietary change alone did not result in normocalcemia. Before resorting to any pharmacological solution, supplementation to the diet of chia seeds (2 g/cat/day) was started. After 4 weeks from the introduction of Salvia hispanica L., all cats achieved normalization of ionized calcium concentration. Conclusion: Chia seeds (Salvia hispanica L.) supplementation could be a useful tool in managing feline idiopathic hypercalcemia.