Effects of Graded Dietary Probiotic Levels on Growth Performance and Muscle Protein Content in Juvenile Golden Trevally (Gnathanodon speciosus)

The golden trevally (Gnathanodon speciosus) is a favourable option for aquaculture due to its fast growth, valuable market value, and exceptional flavour. It is crucial to identify techniques for optimising production through growth enhancement in golden trevally aquaculture. This experiment aimed to assess the effect of grading levels of probiotic (0, 1, 2, 3, and 4 g kg ⁻¹) on the golden trevally, G. speciosus (initial weight 8.51 g ± 0.53). Each diet treatment had three replicates, and fed the fish over a duration of four weeks. The growth performance and protein and fat content in the muscle were evaluated. At the end of the experiment, the incorporation of probiotics into the golden trevally diet resulted in a statistically significant improvement in growth (P < 0.05). The survival rate of fish fed the probiotic diet was not statistically different from that of the control group. Furthermore, at the end of the experiment, the protein concentration was 20.30 to 21.15% in the flesh of golden trevally fed diet B2, B3 and B4, which was significantly increased in comparison to fish fed control diet (P < 0.05). In conclusion, nutritional treatment with probiotics trevally improves growth, survival, and body composition in juvenile golden fish. It is recommended to add 1 - 2 g of Bacillus kg-1 diet of golden trevally to improved growth, survival and protein content. This trial represents the first investigation into the advantages of probiotics for golden trevally; however, researchers should undertake additional studies on physiological effects and stress resilience.