Effects of graded dietary probiotic levels on growth performance and muscle protein content in juvenile golden trevally (Gnathanodon speciosus)

Abstract

The study investigated the impact of four Lugol concentrations and four soaking times on the self-attachment time of fragmental soft coral S. serenei. After fragmentation and soaking, the coral was cultured for 30 days with six replicates for each treatment. After 30 days of culture, the results indicated that the fastest selfattachment time was observed in treatment with 0.5 mL.L− 1 Lugol and soaked for 15 minutes, while the time until complete healing was in treatment without Lugol and soaked for 10 minutes. The Lugol concentration, soaking time, or their interaction did not significantly influence the growth rate, with the exception of the Lugol concentration, which significantly impacted the coral’s growth in length. The study found that survival rates were highest in treatments with 0.5 mL.L− 1 Lugol and soaked for 15 minutes and 1.0 mL.L− 1 Lugol and soaked for 10 min, with a survival rate of 85.00 %. The lowest survival rate (71.67 %) was observed in treatments without Lugol and soaked for 20 minutes and 1.5 mL. L− 1 Lugol for 20 min. Mortalities were observed until day 9, and no further deaths were recorded until the end of the study period. The experiment showed high chlorophyll a and zooxanthellae concentrations in the coral at the start, with no significant differences among the treatments. On days 3 and 6, the chlorophyll a content and zooxanthellae decreased, but showed a slight recovered on day 9 and showed a slight higher than Chl-a and zooxanthallae in coral at initial. The Lugol concentration, soaking time, and their interaction did not significantly affect the chlorophyll a content or zooxanthellae of the coral fragments. Moreover, the highest organic weight was observed in the treatment with 1 mL.L− 1 Lugol and soaking for 15 min, whereas the lowest was recorded in the treatment with no Lugol and soaking for 20 min.