This study was conducted to investigate the effects of dietaryPediococcus acidilactici and folic acid (FA) and their combinations on growth performance, haematological parameters and non-specific immune response ofAcipenser nudiventris. 210 individuals (initial body weight: 12.84± 1.53g) were fed seven practical diets: the basal diet as the control diet was supplemented with two levels ofP.acidilactici (2 and 3 g per kg diet), FA (2 and 4 mg per kg diet) and their combinations. The results showed that the group fed a combined diet ofP. acidilactici and FA (4 mg FA+3 g P. acidilactici per kg diet) showed significant increase in body weight increase (BWI), specific growth rate (SGR), feed conversion ratio (FCR) and condition factor (CF). However, experimental diets had no significant effects on survival rate. Both haematological indices and leucocyte counts were significantly (p<0.05) influenced by dietaryP. acidilactici and FA and their combinations. In the group fed 4 mg FA+3 g P. acidilactici, lysozyme activity and total immunoglobulin (Ig) levels significantly increased compared to those fed other diets (p<0.05). Moreover, the fish fed diets supplemented with 2 mg FA+ 3 g P. acidilactici per kg diet had considerably higher immunoglobulin (IgM) level (p<0.05). Under the experimental conditions, dietaryP.acidilactici and FA had a synergistic effect on enhancing growth performance and immunity ofA. nudiventris.

Keywords: Acipenser nudiventris, Probiotic, Physiological measurements, Immune response