Table 4 showed the average values per diet and oxygen concentration (2 × 2) of intestinal parameters over the whole period. The results
showed that hypoxia had a negative effect on SM and LP by increasing of
the thickness of SM and LP. The effect of diet was found to be significant
on all four intestinal parameters. Fish fed the “Test” diet exhibited both
an increase of the thickness of SM and LP, and also the number of GC and
EG. The interaction between oxygen and diet was only found at SM and
EG in proximal and distal section, respectively.