Background Stichopus monotuberculatus, a tropical sea cucumber species, has attracted significant attention due to its high nutritional value and medicinal properties. However, to date, no studies have investigated the potential of suspension cage aquaculture for this species. Suspension cage farming is one of the most important methods in sea cucumber aquaculture, but its unique structural design often leads to feed loss, which can significantly impact the surrounding aquatic environment. This issue underscores the necessity of investigating innovative solutions to improve feed efficiency. For instance, studying the incorporation of binding agents into feed formulations to produce appropriately shaped sheet-like feed could play a crucial role in altering feed properties. Furthermore, understanding how such modifications influence the feeding behavior and movement patterns of S. monotuberculatus becomes essential for optimizing both the growth performance of the species and the sustainability of the suspension farming system.
Objective The present study investigated the effects of different binders on the stability, palatability, and feeding behavior of sheet feed for the suspension cage aquaculture of S. monotuberculatus, in order to select the most suitable binder for sheet feed used in the cage farming of S. monotuberculatus.
Methods In the basic feed, 0.5% xanthan gum, sodium alginate, carrageenan and cassava starch binder were added to make sheet feed as the experimental feed of the four treatment groups, and the basic feed without adding any binder to make sheet feed was used as the control feed. This study compared the binding performance (including type preservation ability and dissolution loss rate) of different binders, as well as their effects on the feeding behavior and growth of S. monotuberculatus.
Results Both xanthan gum and sodium alginate could significantly improve the type preservation ability and reduce the dissolution loss rate of sheet feed (P<0.05). Both carrageenan and cassava starch improved the shape retention ability of flake feed and also reduced the dissolution loss rate of the feed, but there was no significant difference compared with the control. The cumulative residence time of S. monotuberculatus was significantly decreased by sheet feed in the four treatment groups (P<0.05). The sodium alginate group did not significantly change the cumulative exercise distance and cumulative exercise time of S. monotuberculatus. The cumulative exercise distance of S. monotuberculatus was significantly increased by the sheet feed of carrageenan group and cassava starch group (P<0.05). Xanthan gum group significantly decreased the cumulative exercise time of S. monotuberculatus (P<0.05). After the experiment, the body mass of S. monotuberculatus increased the most in sodium alginate group and the least in xanthan gum group.
Conclusion Sodium alginate significantly enhanced the water resistance of sheet feed without markedly affecting the cumulative movement distance or duration of S. monotuberculatus. Notably, this treatment group demonstrated superior growth effect among all experimental groups. Therefore, sodium alginate was more suitable as the binder for sheet feed.
Significance The results of this study not only provide data support for the development of sheet feed for hanging cage culture of S. monotuberculatus, but also provide a new idea for the research of breeding technology of S. monotuberculatus.
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