Effect of withholding food on serum concentrations of cobalamin, folate, trypsin-like immunoreactivity, and pancreatic lipase immunoreactivity in healthy dogs

Abstract

OBJECTIVE To evaluate the effects of withholding food on the results for measurements of serum concentrations of cobalamin, folate, canine pancreatic lipase immunoreactivity (cPLI), and canine trypsin-like immunoreactivity (cTLI) in healthy dogs. ANIMALS 11 healthy employee- or student-owned dogs. PROCEDURES Food was withheld from the dogs for 12 hours, baseline blood samples were collected, then dogs were fed. Postprandial blood samples collected 1, 2, 4, and 8 hours later were assessed. A mixed-effects ANOVA model with fasting duration (time) as a fixed factor and dog as a random effect was fit for each analyte variable. Additionally, a mixed-effects ANOVA model controlling for the variable of time was fit to assess whether lipemia affected serum concentrations of the analytes. RESULTS The median serum cobalamin concentration was lower at 4 hours (428 ng/L) and 8 hours (429 ng/L) postprandially, compared with baseline (479 ng/L), but this difference was not clinically meaningful. Although there were no substantial differences in serum concentrations of folate, cPLI, or cTLI, postprandial changes in serum concentrations of cTLI or folate could potentially affect diagnoses in some dogs. CONCLUSIONS AND CLINICAL RELEVANCE Although results indicated that feedings rarely resulted in clinically important differences in the median serum concentrations of cobalamin, folate, cPLI, or cTLI in healthy dogs, given the further processing required for lipemic samples, withholding food for at least 8 hours is an appropriate recommendation when measuring these analytes. Similar research is needed in dogs with gastrointestinal disease to determine whether the withholding of food is necessary when measuring these analytes in affected dogs.

The effect of feeding on serum concentrations of cobalamin, folate, trypsin‐like immunoreactivity, and pancreatic lipase immunoreactivity in dogs with signs of chronic gastrointestinal disease

“…Conclusions on equivalence could In healthy dogs, there is a statistically significant but clinically unimportant change in serum cobalamin concentrations obtained 4 and 8 hours postprandially compared with samples collected after withholding food for 12 hours. 11 This mirrored work in people demonstrating a small, clinically unimportant decrease in cobalamin with fasting in men. 6 In our study's cohort of dogs with signs of chronic gastrointestinal disease, whereas cobalamin concentration 2 and 4 hours postprandial was equivalent to values with food withheld for 12 hours, measurement 8 hours postprandially was not equivalent.…”

“…Sample size for this project was determined based on having 90% power in an equivalence test from paired differences with the primary outcome being the paired differences in serum cobalamin concentration at each postfeeding time point (2,4, and 8 hours) compared with the baseline time point in a previous study. 11 The margin of equivalence was set as ±50 ng/L rather than a percentage change to facilitate sample size estimation. This is narrower than the difference seen in Saver et al 11 and was chosen because of the possibility that included dogs would likely have serum cobalamin concentrations close to the lower end of the reference interval and thus to be more conservative in possible conclusions.…”

“…11 The margin of equivalence was set as ±50 ng/L rather than a percentage change to facilitate sample size estimation. This is narrower than the difference seen in Saver et al 11 and was chosen because of the possibility that included dogs would likely have serum cobalamin concentrations close to the lower end of the reference interval and thus to be more conservative in possible conclusions. The previous data showed standard deviation (SD) estimates of paired differences near 70 ng/L, and for our study, we more conservatively assumed a larger SD of 90 ng/L.…”

“…Previous studies found no statistically significant differences in serum cPLI concentrations in healthy dogs after feeding when compared with concentrations after withholding food. 10,11 Although there was variability in serum cPLI concentration between measurements within the same dog, no general pattern could be observed. 10 An individual's dietary fat percentage is not anticipated to influence serum cPLI concentration.…”

Evaluation of trypsin-like immunoreactivity, pancreatic lipase immunoreactivity, cobalamin, and folate in zoo-housed African painted dogs (Lycaon pictus) at a North American zoological facility

“…Folate was supplied in the meat diet at a standard formulation of 1.3 mg/kg dry matter, which is well above the recommended Association of American Feed Control Officials supplementation rate of 0.216 mg/kg dry matter weight for domestic dogs. 16 Recommended folate and cobalamin supplementation levels are not established for African painted dogs. Individual consumption of food may vary based on pack dynamics, but all were in good body condition, so it is assumed that they had adequate consumption of diet.…”