Fig. 1. Postprandial gastric luminal pH of fish and rats. The post-prandial hours (x axis) are in log scale (0 h is the pre-prandial value), and gastric luminal pH (y axis) is shown as mean ± s.e.m. (as error bars, N=8 for fish and N=4 for rats). Fish studied were four 2-month-old rainbow trout (10.24±0.54 g; mean body mass ± s.e.m.) and four 15-month-old rainbow trout (211.4±2.4 g). Since there was no significant difference between these small and mid-sized fish, they were pooled for statistical comparison with rats. Rats studied were four 1-2-month-old rats (120.3±3.2 g). Difference between fish and rats in gastric luminal pH at each postprandial hour is shown with asterisks: ^*P<0.05; ^**P<0.01. Gastric luminal pH of rats was much lower than that of fish at 1-6 h postprandial.