Three-step in vitro digestion model for evaluating and predicting fecal odor emission from growing pigs with different dietary protein intakes.

Objective: The objective of this study was to select an effective in vitro digestion-fermentation model to estimate the effect of decreasing dietary crude protein (CP) on odor emission during pig production and to suggest potential prediction markers through in vitro and in vivo experiments.

Methods: In the in vitro experiment, three diet formulations with different CP contents (170 g/kg, 150 g/kg, and 130 g/kg) but containing the same standardized ileal digestible essential amino acids (SID-EAA) were assessed. Each diet was evaluated by two different in vitro gastric-intestinal phase digestion methods (flask and dialysis), combined with fresh pig feces-ferment inoculation.

Effects of essential oil mixtures on nitrogen metabolism and odor emission via in vitro simulated digestion and in vivo growing pig experiments.

Background: Essential oils (EOs) are extensively used in swine production because of their bioactive action in gut health. In addition, some EOs have the potential to reduce waste emission. The present study aimed to find an optimal combination of carvacrol, thymol and cinnamaldehyde to promote nitrogen utilization and reduce waste emission by a model in vitro and an animal study.