• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.10
• /
• pp.1522-1528
• /
• 2008

The objective of this study was to develop a model for simulating gastric digestion in the pig. The model was constructed to include the chemical and physical changes associated with gastric digestion such as enzyme release, digestion product removal and gastric emptying. Digesta was collected from the stomach cannula of pigs to establish system parameters and to document the ability of the model to simulate gastric digestion. The results showed that the average pH of gastric digesta increased significantly from 2.47 to 4.97 after feed consumption and then decreased 140 min postprandial. The model described the decrease in pH within the pigs' stomach as $pH_t=5.182e^{-0.0014t}$, where t represents the postprandial time in minutes. The cumulative distribution function of liquid digesta was $V_t=64.509e^{0.0109t}$. The average pepsin activity in the liquid digesta was 317Anson units/mL. There was significant gastric emptying 220 min after feed consumption. The cybernetic dynamic system of gastric digestion was set according to the above data in order to compare with in vivo changes. The time course of crude protein digestion predicted by the model was highly correlated with observed in vivo digestion (r = 0.97; p = 0.0001), Model prediction for protein digestion was higher than that observed for a traditional static in vitro method (r = 0.89; p = 0.0001).