Changes in gastric contents in pigs fed a finely ground and pelleted or coarsely ground meal diet

The objective was to characterize the change in stomach contents in relatio n to time after feeding between pigs consuming a restricted amount of a fin ely ground and pelleted (FGP) or coarsely ground meal (CGM) diet. Particula r interest was placed on the concentration of organic acids and ammonia, th e products of microbial fermentation. Thirty barrows were ranked by weight and assigned to a postfeeding time of 2, 4, 6, 8, or 12 h and either the FG P or CGM diet. Initiation and termination of the experiment were staggered over a 2-wk period. The treatment period was 42 d. Percentage of dry matter was higher (P < .01) in the stomach contents of pigs on the CGM diet. Conc entrations of pepsin and protein were higher (P < .05) and ammonia tended t o be higher (P = .10) in the proximal stomach of pigs fed the FGP diet. In contrast, concentrations of acetate and L-lactate were higher (P < .05) in the proximal stomach of pigs fed the CGM diet. Al pigs on the CGM diet had stomachs that graded as normal on visual inspection. There was variable dam age to the stomachs of pigs on the FGP diet. Measurement of chromium Concen tration in the stomach after an oral dose of Cr-EDTA clearly demonstrated t he mixing that occurs between the proximal and distal stomach by 2 h after feeding in pigs consuming the FGP diet, whereas a gradient was maintained i n pigs consuming the CGM diet. Thus, components normally secreted in the di stal stomach return to the proximal stomach. These data show that component s secreted in the distal region; such as acid and pepsin, may play a role i n initiating damage to the stratified squamous mucosa. High concentrations of organic acids in the stomach of pigs on the CGM diet were not associated with damage to the stratified squamous mucosa in the esophageal region.