Influence of Bile Salts and Pancreatin on Dog Food during Static In Vitro Simulation to Mimic In Vivo Digestion

Simple Summary Animal experiments are limited owing to concerns such as the ethics of animal use. To address the issue, an in vitro model for the stimulation of digestibility has been proposed. In the model, the physiological conditions of the oral cavity, stomach, small intestine, and ileum are selectively simulated, requiring careful consideration of the physiological parameters in each step. However, to date, the physiological roles and actions of digestive enzymes during the in vitro digestion of food ingredients remain unclear. In the present study, the effects of pancreatin and bile salts, which are the main digestive enzymes of the digestive tract, were evaluated. During in vitro digestion, the digestibility of crude protein, fat, and dry matter were influenced by the addition of various concentrations of pancreatin and bile salts. Therefore, the concentrations of pancreatin and bile salts should be carefully considered when applied in a static in vitro digestion model. The addition of pancreatin and bile salts in different concentrations during in vitro digestion causes changes in the digestibility of crude protein (CP), fat, and dry matter (DM). The effects of bile salts and pancreatin on the digestibility of ether extract (EE), CP, and DM in developing a static in vitro digestion model for dogs were assessed using different concentrations of pancreatin (0, 1, 2.5, 5, and 10 g/L digestive solution) and bile salts (0, 2.5, 6.25, 12.5, and 25 g/L digestive solution). The data were analyzed using one-way analysis of variance. Digestibility of EE increased with the addition of bile salts (p < 0.05), whereas that of CP decreased with <= 0.25 g (1.0 g/L digestive solution) pancreatin. The digestibility of DM decreased significantly in all groups supplemented with >= 3.125 g (12.5 g/L digestive solution) bile salts and 0.25-2.5 g (1-10 g/L digestive solution) pancreatin and was the lowest with 6.25 g (25 g/L digestive solution) of bile salts (p < 0.05). These findings could facilitate the development of effective static in vitro digestion models for dogs.