PSIX-9 Digestibility assessment of various carbohydrate sources in dry cat food.

Abstract The wild ancestors of domestic cats were obligate carnivores, consuming prey with minimal carbohydrate content. Consequently, carbohydrates have often been overlooked in feline nutrition, with greater emphasis placed on proteins and fats. However, carbohydrates are critical in the production of commercial extruded dry kibble, where they provide structural integrity and contribute to texture and flavor through interactions with proteins. This study aimed to assess the effects of different carbohydrate sources on nutrient digestibility in dry cat food. Feed pellets containing corn, potatoes, rice, sweet potatoes, or tapioca as the sole carbohydrate source were produced industrially, with all other formula components kept constant. Nutrient composition analysis showed moisture (6.77% ± 0.76%), crude protein (27.41% ± 2.11%), crude fat (12.45% ± 1.23%), fiber (2.90% ± 1.21%), and crude ash (7.47% ± 0.82%). For each experimental group, digestibility was assessed in 10 adult cats. (1:1 male-to-female ratio; average age 30.42 ± 21.73 months). Carbohydrate digestibility showed no significant differences across feeds (10.37% ± 7.59%; P < 0.05). However, rice-based feed demonstrated significantly higher protein digestibility (82.05% ± 5.65%) compared to feeds based on potatoes (70.25% ± 7.61%), sweet potatoes (67.93% ± 8.88%), or tapioca (70.67% ± 10.21%), while no significant difference was observed with corn-based feed (P < 0.05). Additionally, rice-based feed enhanced the digestibility of several amino acids, including aspartate, cysteine, glycine, histidine, leucine, lysine, methionine, phenylalanine, serine, and threonine, compared to other carbohydrate sources. These findings suggest that carbohydrate type can influence protein and amino acid digestibility in dry cat food, offering insights for optimizing feline diets and improving animal welfare through feed formulation.