Nutritional value of common carbohydrate sources used in pet foods

Diet digestibility can vary based on factors such as the type of ingredients, processing techniques, formulation, fiber content, and nutrient interactions. Unlike proteins and fats, there is no specific carbohydrate requirement, which typically constitutes 30%–60% of commercial dried dog foods. Because of the significant proportion of carbohydrates in dog food, this study aimed to evaluate the differences in nutrient digestibility among barley, brown rice, corn, mung bean, and rice, which are common carbohydrate sources in commercial dog foods. All experimental diets had consistent chemical compositions. The digestibility of each carbohydrate source was evaluated using the total feces collection method in four castrated male and four neutered female beagles with an average age of 4.58 ± 0.14 years. The average daily dry matter intake of the five experimental diets was 203.0 ± 3.23 g/day. The percentage of dry matter digestibility of the apparent total tract digestibility (ATTD) was the highest for rice and corn at 92.45% and 92.95%, respectively, followed by brown rice (91.61%), barley (88.81%), and mung beans (80.74%). The percentage of nitrogen-free extract digestibility was also high for rice, corn, and brown rice at 97.08%, 96.14%, and 95.56%, respectively, followed by barley at 90.10% and mung bean at 83.38%. Amino acid digestibility analysis revealed no statistically significant differences between rice, corn, brown rice, and barley, except for methionine, which is an essential amino acid. Although the ATTD and amino acid profile of the mung bean-based diet were less efficient than those of the other test diets, the overall digestibility was satisfactory and there were no significant differences in palatability. The differences in digestibility observed in mung bean-based diets compared to other grain-based diets can be attributed to variations in the starch and fiber content of the raw materials. By leveraging these characteristics, mung bean-based diets may offer strategic benefits for glycemic control and weight management in dogs. Our results may serve as a basis for formulating appropriate diets for dogs.