Toxicity and toxin identification in Colomesus asellus, an Amazonian (Brazil) freshwater puffer fish

Abstract

Toxicity and toxin identification in Colomesus asellus, an Amazonian (Brazil) freshwater puffer fish. By using four different techniques--mouse bioassay, ELISA, HPLC and mass spectrometry-we evaluated the toxicity in the extracts of C. asellus, a freshwater puffer fish from the rivers of the Amazon, and identified for the first time the components responsible for its toxicity. The T20G10 monoclonal antibody raised against TTX, and employed in an indirect competitive enzyme immunoassay, showed very low affinity for the C. asellus extracts, indicating that TTX and its analogs are not the main toxic components of the extracts. This antibody was efficient in detecting presence of TTX in a total extract of Sphoeroides spengleri, which is one of the most toxic puffer fish found in the Atlantic coast. Extracts of C. asellus were toxic when administered intraperitonially into mice with an average toxicity of 38.6+/-12 mouse unit (MU)/g, while HPLC analysis indicated a lower toxin content (7.6+/-0 5MU/g). The HPLC profile showed no traces of TTX, but only the presence of PSPs (STX, GTX 2 and GTX 3). These toxins were also confirmed by electrospray ionization mass spectrometry.

Occurrence of paralytic shellfish toxins in Cambodian Mekong pufferfish Tetraodon turgidus: Selective toxin accumulation in the skin

“…was non-toxic, both in the rainy and dry seasons. As in the freshwater or brackish water species previously reported (Laobhripatr et al, 1990;Mahmud et al, 1999a, b;Lin et al, 2002;Panichpisal et al, 2003), the toxin localized mainly in the skin (Table 1), and the toxicity scores (4-37 MU/g) were comparable to those of the Bangladeshi freshwater pufferfishes T. cutcutia (2-20 MU/g) and C. patoca (2-40 MU/g) (Zaman et al, 1997), and the Brazilian freshwater species C. asellus (19-53 MU/g) (Oliveira et al, 2006). Because the minimal lethal dose (MLD) of PST in humans is estimated to be 3000 MU (Noguchi et al, 1997), the consumption of approximately 100 g of the skin or ovary (with a toxicity of approximately 30 MU/g) can be fatal.…”

“…suvatii from Thailand, T. cutcutia, Chelonodon patoca from Bangladesh, and Colomesus asellus from Brazil are PSTs (Kungsuwan et al, 1997;Zaman et al, 1997Zaman et al, , 1998Oliveira et al, 2006). The presence of both TTX and PSTs within the same species is also documented for the Thailand freshwater pufferfish T. fangi (Saitanu et al, 1991;Sato et al, 1997), whereas palytoxin-like substance(s) in addition to PSTs are detected in the Bangladeshi specimens of Tetraodon sp.…”

Clinical and epidemiological study of 27 poisonings caused by ingesting puffer fish (Tetrodontidae) in the states of Santa Catarina and Bahia, Brazil

“…In Florida's marine waters (USA), puffer fish have been confirmed to be a hazardous reservoir of STX 17 and this toxin was responsible for 28 poisoning cases between 2002 and 2004 8 . A study in Brazil identified saxitoxin and gonyautoxin as the components responsible for toxicity in Colomesus asellus, a freshwater puffer fish 23 . Without further studies to identify the toxins related to puffer fish poisonings, it is not possible to assume which toxin caused the symptoms of puffer fish poisoning in the regions of this study.…”

“…Despite the evidence of increased possible poisoning from consuming meat of the Sphoeroides genus, the spotted puffer fish 13,23 , the general public and fishermen have little knowledge about the puffer fish species. Therefore, based on our study, we do not recommend consumption, even in small amounts, of flesh and other tissues of puffer fish.…”

“…1 and 2). A study in Brazil identified the components responsible for toxicity in Colomesus asellus, a freshwater species found in the Amazon region, to be saxitoxin and gonyautoxin 4,10 , toxins associated with PSP and not TTX 23 . Another study of Sphoeroides spengleri, a species found along the Atlantic coast, detected TTX and analogues (anhydro-TTX, Tetrodonic Acid and 4-epi-TTX): OLIVEIRA et al (2003) 22 showed that TTX levels in muscle, skin, and viscera from fish of the Sphoeroides genus are high and a risk to consumers, whereas levels in Lagocephalus genus are low and in theory present a lower degree of risk.…”