Specific activities of chitinase in digestive gut of Rachycentron canadum fed test diets containing graded levels
of shrimp waste meal over a 6-week period. (A) 0%, (B) 10% SWM, (C) 20% SWM and (D) 25% SWM. Columns
with different letters are significantly different from the control group (P < 0.05).