The value of sea urchin, Lytechinus variegatus, egesta consumed by shrimp, Litopenaeus vannamei

Abstract

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.

Effects of sea urchin feces on behaviors, digestion ability, growth, and resistance of the sea cucumber Apostichopus japonicus

“…Food preference is affected by the nutritional and physiological requirements (Lyons & Scheibling, 2007) and digestive capabilities (Lowe & Lawrence, 1976) of echinoderms. With regular ingestion of natural fresh sea urchin feces that contains readily available live microorganisms, the sea cucumbers intestines possibly became colonized with customized microbial communities to further utilize the remaining nutrients in sea urchin feces (Jensen et al, 2018). Therefore, the feces probably better meets the requirements of digestion and thus is more attractive to small A. japonicus after a short period of aquaculture.…”

“…This signifies that fecal diet enhances the intestinal microbial composition of A. japonicus, and thus has the potential to allow small sea cucumbers to achieve the optimal digestibility of nutrients (Wang et al, 2016) and enhance the resilience ability of small sea cucumbers (Li et al, 2009;Thompson et al, 2010). Since probiotics in food would alter or enhance the digestive ability (Liu et al, 2009;Thompson et al, 2010;Jensen et al, 2018), probiotics is commonly used in aquaculture (Wang et al, 2016). Nevertheless, probiotics serving as allochthonous species showed no significant impact on the composition of fecal microbial community in humans (Bjerg et al, 2014;Hanifi et al, 2014;Laursen et al, 2017).…”

Sustainable aquafeed and aquaculture production systems as impacted by challenges of global food security and climate change

“…With two production species, production efficiency is increased due to the amount of aquafeed fed being the same for the combined production of two species (Boyd et al, 2020). The prospects of IMTA systems has been demonstrated in the results of recent laboratory research whereby satisfactory growth of a marine shrimp species was exclusively maintained through provision of the egesta of sea urchins (Jensen et al, 2019). However, with the exception of invertebrate integration (scallops) to macroalgae sites in Sanggou Bay, China (Shi et al, 2013), the management and financial feasibility of commercial‐scale IMTA production have yet to be demonstrated.…”

Microbial Composition and Genes for Key Metabolic Attributes in the Gut Digesta of Sea Urchins Lytechinus variegatus and Strongylocentrotus purpuratus Using Shotgun Metagenomics

“…However, the grazing enables the sea urchins to metabolize and transform the ingested seagrass and macroalgal biomass into rich organic nutrients. Thus, despite their potentially damaging effect, sea urchins also play an essential ecological role in structuring the communities in their habitats [5,12,[14][15][16][17].…”

“…These gut egesta are an important source of nutrients to marine organisms such as fish, crustaceans, shellfish, and other echinoderms [15,[27][28][29]. The nutritional benefit of the green urchin egesta has also been shown to enhance the growth and the taste quality of shrimp Litopenaeus vannamei as compared to laboratory-formulated feed alone [14]. One important aspect of these nutrient transitions is nitrogen assimilation into amino acids and nucleotides, which are essential macromolecules for all living organisms [30].…”