Effects of Single and Mixture Probiotic Supplements on Growth, Digestive Activity, Antioxidative Status, Immune and Growth-Related Genes, and Stress Response of Juvenile Red Sea Bream (Pagrus Major)

A 50-day feeding trial was conducted to evaluate the efficiency of single and mixed strains of probiotic bacteria supplements on juvenile red sea bream (Pagrus major). The study investigated the growth, digestibility, hemato-biochemistry, antioxidant, immune, immune, and growth gene expression and stress responses of P. major. Three hundred juvenile P. major ( 21.56 ± 0.09  g) were randomly distributed into fifteen 200-L polyethylene tanks (20 fish per tank) in triplicate of 5 treatments designated as D1 = the basal diet; Streptococcus faecalis (SF) T − 110   5 × 106 cfu/g diet and Bacillus amyloliquefaciens (BA) TOA 5001   5 × 105 cfu/g diet in the second group (D2) at 0.2%; mix SF T − 110   1 × 106 cfu/g diet, Lactobacillus plantarum (LP) TO − A   4 × 105 cfu/g diet, Bacillus mesentericus (BM) TO − A   1 × 102 cfu/g diet, BA TOA 5001   5 × 105 cfu/g diet in the third group (D3) at 1%; mix SF T − 110   1 × 106 cfu/g diet, LP TO − A   4 × 105 cfu/g diet, and BM TO − A   1 × 102 cfu/g diet in fourth group (D4) at 0.5%; and single strain BA TOA5001 5×105 cfu/g diet in the fifth group (D5) at 0.5% of dietary proportion. Results showed that D2 and D3 fish groups exhibit better performance, followed by D4, D5, and control group D1. This finding demonstrated that the use of BA in mix strain probiotic bacteria diet (D2, D3) had improved immune response, antioxidant enzymes, immunity (TNF-a, IL-1b), and growth-related (IGF-1, IGF-2) mRNA expression of juvenile P. major compared to the mix strain D4, single strain D5, and the control D1. Furthermore, single strain D5 and mix strain D4 also exhibit relatively better immune responses in P. major than in control D1. Considering the overall fish performances, mix strain SF+BA (D2) and mix strain SF+BM+LP+BA (D3) were the recommended potential mix strain probiotic bacteria supplement for P. major and may be useful also for other related aquatic species.