Effects of dietary protein levels on growth performance, amino and Fatty acids of juvenile sandfish, Holothuria scabra (Jaeger, 1833)

The experiment was carried out for 120 days to determine the optimal dietary protein requirement for the growth of sandfish, Holothuria scabra. The experiment used 12 plastic containers sized 59x47x37 cm, and each container stocked 30 individual hatchery-produced sandfish juveniles (initial weight= 2.70 +/- 0.01 g). Experimental diets with different levels of protein, i.e., 10% (A), 20% (B), and 30% (C) as a treatment; it was as dry pellet with 3 mm diameters. Sandfish were fed with experimental diets once in the afternoon at 2 % biomass. Results of the experiment showed that sandfish fed a 20% protein diet has the highest final weight (5.10 +/- 0.02 g), specific growth rate (SGR; 0.53 +/- 0.01 % day-1), and feed efficieny (FE; 62.48 +/- 0.13) and is significantly different compared to other treatments (p<0.05). On the other hand, feeding with different dietary protein levels did not influence the survival rate greatly (p>0.05), ranging from 85.00-95.83%. The total amino acid content of sandfish juveniles in treatment B was highest (6.62%) and followed by C (6.27%) and A (4.75%). Likewise, the highest fatty acid content was also found in treatment B (0.440%) followed by treatments A and C of 0.416%; 0.332% respectively. Results of the present study found the best feed was treatment B at 20 % protein content. Moreover, based on statistical analyses, it is suggested that dietary protein requirement for maximum growth of juvenile sandfish is 16%.