The microsporidian parasite Enterocytozoon hepatopenaei (EHP) is currently one of the most severe diseases in many of major shrimp producing countries, causing devastating effect on shrimp production with significant reduction in success rate and profit. A nine-week trial was conducted to evaluate the efficacy of preventative diets in suppressing EHP in white leg shrimp Penaeus vannamei under controlled laboratory conditions. A diet with 43% protein was used as a basal diet for negative control (NC) and positive control (PC) treatments. 7 preventative diets were then supplemented with functionally preventative packages to deliver different modes of action for controlling EHP in the hepatopancreas of shrimp. Each of the 9 treatments was replicated 5 times. Specific pathogen free (SPF) shrimp were stocked in 250L tank of seawater with 50 shrimp each (~200 shrimp/m2). Following a 14-day pre-challenge period, shrimp were exposed to EHP via oral challenge (Per os method) for 7 days. Post-challenge monitoring continued for 42 days. According to the results of our study, there were no significant difference in the EHP load among groups of treatment after 7 days of challenge. EHP load in the hepatopancreas of shrimp, however, increased dramatically in positive control treatment after 21 days of challenge. In contrast, shrimp in the groups fed preventative diets T2, T3, T6, T7 showed pretty good EHP control with significantly lower EHP loads compared to the positive control treatment. Other growth performance including average daily gain, feed conversion ratio and survival rate were also measured after the trial which indicated the best performance of shrimp in T2. In conclusion, the trial results showed the potential of preventative diets as a solution for EHP management in shrimp aquaculture.