European sea cucumbers have recently been targeted for commercial exploitation, resulting in increased attention to aquaculture development. Since information on effective diets for European species is still scant , a short-term feeding trial was conducted to evaluate sustainable feed performances on adult specimens of Holothuria forskali.
Three feed formulations were used to enrich natural sediment and fed sea cucumbers for 5 weeks (Figure 1). Two control treatments, with only natural sediment (Control+ ) or without both sediment and feeds (Control-), were also included in the experimental design for a total of 5 treatments. After 1 week of starvation, 60 individuals were weighed and ra ndomly distributed into 15 tanks (3 tanks/treatment) of a flow-through system. During the experiment (after 2 weeks, T1, and after 4 weeks, T2) feeding rates (FR) were evaluated through defecation, and at the end of the end of the experiment, survival rate a nd weight changes were assessed.
A 100% survival rate was observed. FR values at T1 were comparable among feeding treatments, while at T2 values increased significantly for individuals fed with enriched sediment (Figure 2). T otal weight did not show significant differences between feeds and times, although a positive trend was observed in individuals fed with the experimental feeds against a negative trend observed in the controls . Similarly, positive values of specific growth rate and weight change were observed for Feed-1, Feed-2 and Feed-3, while Control+ and Control- showed negative values. This study provides initial evidence for the potential use of sustainable feeds based on food industry discards for sea cucumber aquaculture , although longer trials are needed to have a more comprehensive picture .