Efficacy of single and mix probiotic bacteria strain on growth indices, physiological condition and bio-chemical composition of juvenile amberjack (Seriola dumerili)

Abstract

This study presents the effect of integrating single strain (Bacillus amyloliquefaciens (BA)) and mix strain (Streptococcus faecalis (SF), Lactobacillus plantarum (LP) and Bacillus mesentericus (BM)) probiotic bacteria on growth, physiologycal condition and body composition of juvenile Amberjack (initial average body weight 5.61 ± 0.11 g). Three experimental diets were formulated, the basal diet CD1 (0% probiotic supplement), diet D2 (0.2 % BA supplement, 1.59 × 108 CFU/g) and diet D3 (1% SF + LP + BM supplement, 2.86 × 108 CFU/g diet). Fifty fish were stock in each 500 L poly tank (duplicate tank per treatment) and fed the test diets for 75 days. Sampling of weights and length was conducted at 60 and 75 days, while the whole body samples were collected at the end of the feeding trial. The results showed a significantly higher condition factor (K), relatively condition factor (Kn), and a numerically high length weight relationship (LWRs) coefficient (b) for fish feed BA supplement compared to control and SF + LP + BM group. The coefficient (b) values of the allometric growth trend was improved for BA supplement with no significant difference from isometric growth coefficient (b = 3). The growth parameters, feed utilization, survival (%) and whole body composition of fish fed the test diets were not significantly altered. A numerically high mono-saturated fatty acid (MUFA) and, Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) ratio was noted in fish group fed BA supplement, suggesting an improve physiological condition of fish. This results demonstrated that integration of single strain Bacillus amyloliquefaciens at 0.2 % has significantly improved physiological condition for Amberjack juvenile. Further research is recommended to determine the dietary effects of the single strain (BA) and mix strain (SF + BM + LP) on growth and health of fish.