Comparing trace element concentrations in muscle tissue of marbled eel Anguilla marmorata reared in three different aquaculture systems

Abstract

There is a growing trend towards culturing fish in intensive recirculating aquaculture systems, which have a reduced need for water exchange compared to many other systems. However, it is unknown whether these intensive aquaculture operations facilitate bioaccumulation of trace elements in fish tissue. The present study therefore evaluated and compared the accumulation of 20 trace elements in the flesh of marbled eel Anguilla marmorata reared in 3 different systems: a recirculating aquaculture system (RAS), a biofloc technology system (BFT), and a concrete pond (CP; traditional method). In the BFT system fish were also raised in polyculture with tilapia Oreochromis niloticus and water spinach Ipomoea aquatica Forsk. Fish were fed the same feed and reared in water from the same source. The trace elements (Al, As, Ba, Be, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ti, V, and Zn) in the fish flesh were analyzed by inductively coupled plasma-optical emission spectrometry. Fish reared in the RAS had elevated concentrations of only a single element (Al) compared with CP fish. This element was also elevated in BFT fish and was probably related to the high Al concentration in the fish feed. Fish reared in the BFT system also showed significantly higher levels of As, Ba, Cr, Fe, Mn, Ni, Se, Sn, Sr, Ti, and Zn compared to both CP and RAS fish. The observed levels of (1) As in fish from BFT systems and (2) Pb in fish from both RAS and BFT systems exceeded national and international legislatory limits. Our results suggest that regular monitoring of trace element concentrations in BFT and RAS should be implemented in the future for this species.

Assessment of selected trace metals in fish feeds, pond water and edible muscles of Oreochromis mossambicus and the evaluation of human health risk associated with its consumption in Vhembe district of Limpopo Province, South Africa

“…The fish feed recorded 1.24 and 1.53 mg/kg of antimony ( Table 6 ). A study by Li et al [ 83 ] discovered that Marbled eel fish feed had a mean Sb concentration of 0.26 mg/kg and the fish muscles recorded mean values of 400 μg/kg, 100 μg/kg and 480 μg/kg of Sb from recirculating aquaculture system, biofloc technology and concrete ponds, respectively, which were higher than the Sb found in this study.…”

“…Ba accumulation in O. mossambicus muscles ranged between 7.38–88.57 μg/kg ( Table 4 ). The study by Li et al [ 83 ] recorded higher levels of Ba which varied between 760–1540 μg/kg in fish muscles. Scher [ 84 ] proposed 1200 μg/kg of Ba as acceptable daily intake only for individuals above 60 kg of body weight.…”

Effects of different LED light spectra on growth and immunity of the Japanese eel (Anguilla japonica) and giant mottled eel (A. marmorata)

“…LZM also combines and metabolizes advanced glycosylation end products produced from reactive oxygen species that would otherwise accumulate and cause harm to organisms. Similar to the antioxidant system, LZM may also be affected by stress responses (Eslamloo et al, 2015;Zheng et al, 2016;Gao et al, 2017;Li et al, 2018). LZM expression levels increase under a red light environment in the pikeperch Sander lucioperca (Baekelandt et al, 2019).…”

“…Indoor RAS can reduce the water exchange rate to 1/30-1/50 that of traditional outdoor aquaculture ponds, and improve the production capacity by more than ten times (Deviller et al, 2005;Martins et al, 2011). A. japonica and A. marmorata are usually reared in an enclosed RAS at high density (Hsu, 1997;Li, 2018). Fish tend to be more easily affected by disease in intensive aquaculture systems due to the stress-induced weakening of their immune systems (Raman et al, 2013).…”

A Review on Biofloc System Technology, History, Types, and Future Economical Perceptions in Aquaculture

“…Recent research has focused on Anguilla spp. [79] and Anguilla marmorata [80]. The cultivated species in BFT exhibit common characteristics, including the ability to feed on suspended bioflocs and specialized morphological structures [6,17].…”