Specific enzyme activities for protease across all treatments were
presented in Fig. 2. At early larval stages (Z3 and M3), specific protease
activity in shrimp was not significantly different between probiotic
treatment and control. In contrast, at the subsequent ontogenetic
stages (PL1–2 and PL7–8), the highest protease activity (0.21±0.02Umg−1
protein and 0.26±0.02Umg−1 protein, respectively)was observed inT-2
and there was a significant difference (Pb0.05), as compared with the
control (0.16±0.02 U mg−1 protein and 0.17±0.01 U mg−1 protein,
respectively). Similar resultswere also observed in T-3 at the PL7–8 stage
(Pb0.05). However, there was no significant difference among all
treatments (T-1, T-2 and T-3) in protease activity. T-1 showed no
significant difference (PN0.05) in protease activities of shrimp larval
compared with that of the control during the whole trial.