DVM/Nutrition Resident Colorado State University teaching hospital Fort Collins, CO, United States
Abstract:
Background: An increase in reported cases of copper hepatitis in dogs and the absence of established safe upper limits for copper content in dog food necessitate understanding copper composition of diets. Examining copper solubility allows for a broader understanding of factors that may contribute to this disease.
Objective: The study aim was to assess the solubility of copper and zinc in dog food using a previously validated in vitro digestion model.
Methods: A total of 63 diets, including both prescription and over-the-counter varieties, underwent simulation of gastric digestion by using HCL and pepsin, followed by small intestinal digestion with digestive enzymes and buffers to assess copper and zinc solubility during each phase. Analysis also compared solubility percentages among different diet types to see if other characteristics of the diet could affect copper absorption.
Results: Preliminary results show the median copper concentration in solution post gastric digestion was 0.265 ppm, while following intestinal digestion, it was 0.297 ppm. The median zinc concentration post gastric digestion was 5.50 ppm and decreased to 1.604 ppm after intestinal digestion. The median solubility of copper after intestinal digestion between diets was 48.3% and ranged from 29.2% to 92.4%, revealing a wide range in solubility percentages.
Conclusion: These results offer insights into the dynamics of copper and zinc solubility during digestion in dog food using an in vitro model. This emphasizes the need for further exploration into factors influencing copper solubility and how it may contribute to hepatic copper accumulation in dogs.
