Use of Tritiated Water to Assess, In Vivo, the Effect of Dietary Particle Size on the Mixing of Stomach Contents of Swine

Abstract
The extent of mixing in vivo of the stomach contents of swine fed cracked versus finely ground corn was assessed by labeling the body water pool with tritiated water and measuring 4 hr. later the specific activity of the water in 17 different regions of the stomach contents. Pigs fed the fine corn diet had a uniform distribution of tritiated water throughout the stomach contents while those fed cracked corn showed a marked gradient in specific activity of stomach water with the lowest values occurring in the esophageal region of the stomach. A gradient in pH was also observed in pigs fed the cracked corn, but not in those fed the fine corn diet. The percent moisture of stomach contents was lower in all regions of the stomach when cracked corn was compared to fine corn. These data demonstrate that stomach contents from pigs fed finely ground corn undergo more extensive mixing in vivo than those from pigs fed cracked corn, probably as a result of the greater fluidity of the contents. This increased mixing of stomach contents allows the secreted acid and pepsin from the lower part of the stomach to come into contact with the relatively unprotected esophageal mucosa. This may lead to the increased incidence of esophagogastric ulcers and related lesions associated with the feeding of finely ground diets. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science.