Evidence of rapid transfer and bioaccumulation of Microcystin‐ LR poses potential risk to freshwater prawn Macrobrachium rosenbergii (de Man)

Abstract

Microcystins accumulate in aquatic organisms and can be transferred to higher trophic levels, eventually affecting vector animals and consumers. We examined three levels of an aquatic food chain (Microcystis aeruginosa, Daphnia magna and Macrobrachium rosenbergii) to identify the transfer efficiency and risk of microcystin on prawns. Samples were analysed using ultra performance liquid chromatography‐mass spectrometry (MS)/MS and microcystin‐LR (MC‐LR) distributions in prawn tissues were studied. The results showed that prawns accumulate MC‐LR both directly from M. aeruginosa and indirectly through D. magna which was pre‐exposed to M. aeruginosa. MC‐LR was detected in the gills, digestive tracts and hepatopancreas of the prawns 2 h after exposure. MC‐LR accumulated in prawns to 0.49 ± 0.04 μg g−1 dry weight in hepatopancreas within 24 h, while it was not detected in muscle samples, and rarely appeared in blood samples in such a short period. Although MC‐LR was not detected in muscle, the head including hepatopancreas of the prawns accumulated troublesome amounts of MC‐LR. These results demonstrate that microcystis blooms in prawn farming potentially pose a risk to human consumers, although prawns may be exposed to the bloom for a very short time, hence regular monitoring of blue green algae population is recommended.

Cyanobacteria and Macroinvertebrate Relationships in Freshwater Benthic Communities beyond Cytotoxicity

“…Studies of protein and lipids, especially fatty acid biomarkers, have also confirmed that cyanobacteria are essential for macroinvertebrate survival, especially in winter when no other food is within reach [ 70 , 95 ]. Benthic macroinvertebrates can eat cyanobacteria from benthos and plankton [ 101 , 102 ].…”

“…The relationship between cyanobacteria and benthic macroinvertebrates is not only trophic, but they can also interact biologically by simply living in the same habitat. As is known, invertebrates can be affected by cyanotoxins through their ingestion, either diluted in water and associated with particles (sediment or cyanobacterial cells) or by contact and diffusion through integument, eggs or gill membranes [ 30 , 86 , 97 , 101 , 102 , 103 , 107 ]. The harmful effect of this cohabitation has been studied more in plankton than in benthic invertebrates [ 72 , 94 ].…”

“…[ 2 , 32 , 105 , 120 , 121 ]. Interestingly, hepatopancreas seems to be the main target organ in Crustacea and Mollusca independently of cyanotoxins [ 2 , 30 , 99 , 101 , 122 , 123 , 124 , 125 ], but only occurs in muscle when toxin exposure thresholds are reached [ 30 ]. Curiously, some studies have highlighted that most cyanobacteria extracts, and even those species or strains that do not produce toxin, are more harmful than purified cyanotoxins by showing that cyanobacteria contain other toxic compounds beyond known toxins [ 2 , 31 , 90 , 123 ].…”

Accumulation of microcystins in a dominant Chironomid Larvae (Tanypus chinensis) of a large, shallow and eutrophic Chinese lake, Lake Taihu

“…Finally, although MCs cannot biomagnify through the food chain in most circumstances, food chain transfer of MCs has been found in some studies 47 48 . CMC concentrations in the present study were extremely high during the warmer months, and given that chironomid larvae are excellent food sources for certain fishes 22 , the MCs in T. chinensis potentially could be transferred to higher trophic levels.…”

An Overview of Cyanobacteria Harmful Algal Bloom (CyanoHAB) Issues in Freshwater Ecosystems

“…Zooplankton have been clearly identified as the best bioaccumulator of cyanotoxins and may transfer them to higher trophic levels in the aquatic food web [141][142][143][144]. Mollusks have also been shown to accumulate high concentrations of cyanotoxins with hepatopancreas being the organ presenting the highest concentrations followed by the intestines [115,145].…”