Abstract:
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 TOA5001 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.
