Fig. 1. Pi concentrations of the luminal fluid (A) and pH of the adherent and luminal fluid (B) from various sections of the alimentary canal in rainbow trout consuming commercial feed pellets. GI, gastro-intestinal; St, stomach; Pc, pyloric caeca; I-a, pyloric caeca region of the proximal intestine; I-b, post pyloric caeca region of the proximal intestine; I-c, first 1/2 of the distal intestine; I-d, second 1/2 of the distal intestine; Adherent, adherent fluid; Luminal, luminal fluid. Each column represents the mean ± S.E.M. (N=5 fish). Samples were collected 6 h postprandial.