Evaluation of tropical water sources and mollusks in southern Brazil using microbiological, biochemical, and chemical parameters.

Florianópolis, a city located in the Santa Catarina State in southern Brazil, is the national leading producer of bivalve mollusks. The quality of bivalve mollusks is closely related to the sanitary conditions of surrounding waters where they are cultivated. Presently, cultivation areas receive large amounts of effluents derived mainly from treated and non-treated domestic, rural, and urban sewage. This contributes to the contamination of mollusks with trace metals, pesticides, other organic compounds, and human pathogens such as viruses, bacteria, and protozoan. The aim of this study was to perform a thorough diagnosis of the shellfish growing areas in Florianópolis, on the coast of Santa Catarina. The contamination levels of seawater, sediments, and oysters were evaluated for their microbiological, biochemical, and chemical parameters at five sea sites in Florianópolis, namely three regular oyster cultivation areas (Sites 1, 2, and oyster supplier), a polluted site (Site 3), and a heavily polluted site (Site 4). Samples were evaluated at day zero and after 14 days. Seawater and sediment samples were collected just once, at the end of the experiment. Antioxidant defenses, which may occur in contaminated environments in response to the increased production of reactive oxygen species (ROS) by organisms, were analyzed in oysters, as well as organic compounds (in oysters and sediment samples) and microbiological contamination (in oysters and seawater samples). The results showed the presence of the following contaminants: fecal coliforms in seawater samples (four sites), human adenovirus (all sites), human noroviruses GI and GII (two sites), Hepatitis A viruses (one site), JC Polyomavirus in an oyster sample from the oyster supplier, Giardia duodenalis cysts, and Cryptosporidium sp oocysts (one site). Among organochlorine pesticides, only DDT (dichlorodiphenyltrichloroethane) and HCH (hexachlorocyclohexane) were detected in some sediment and oysters samples in very low levels; site 4 had the highest concentrations of total aliphatic hydrocarbons, PAHs, and linear alkylbenzenes (LABs) found either in oysters or in sediment samples. The major concentration of fecal sterol coprostanol was found at site 4, followed by site 3. After 14 days of allocation in the four selected sites, there was a significant difference in the enzymes analyzed at the monitored spots. The detection of different contaminants in oysters, seawater, and sediment samples in the present study shows the impact untreated or inadequately treated effluents have on coastal areas. These results highlight the need for public investment in adequate wastewater treatment and adequate treatment of oysters, ensuring safe areas for shellfish production as well as healthier bivalve mollusks for consumption.

Comparative effect of benzocaine, menthol and eugenol as anesthetics for juvenile fat snook / Efeito comparativo da benzocaína, mentol e eugenol como anestésicos para juvenis de robalo peva

The present study evaluated different concentrations of benzocaine, eugenol and menthol for induction of anesthesia in juveniles fat snook (Centropomus parallelus), aiming to determine the most suitable product in terms of induction and recovery time, and the minimum optimal dose for each anesthetic. Concentrations of 50, 75, 100 and 150 mg L-1 of benzocaine; 25, 37.5, 62.5 and 50 mg L-1 of eugenol and 50, 100, 150 and 200 mg L-1 of menthol were tested at 21°C. During the procedure of anesthesia, four stages, from reduction of opercular movements to total loss of reaction to stimulus were monitored. While anesthetized, fish were subjected to biometric procedure and then were placed in an aquarium anesthetic free, to observe the recovery time.  Concentrations of 75, 37.5 and 150 mg L-1 of benzocaine, eugenol and menthol, respectively, were considered optimal. By presenting several qualities as an anesthetic and also because it can be used efficiently (time to anesthesia in approximately three minutes and recovery in less than five minutes) at low concentrations, eugenol is the most recommended for anesthesia of juvenile fat snook.

Foram avaliadas diferentes concentrações de benzocaína, eugenol e mentol na indução anestésica em juvenis do robalo-peva (Centropomus parallelus), a fim de determinar o produto mais adequado em termos de tempo de indução e recuperação e o mínimo ótimo de cada anestésico. Foram testadas as concentrações de 50, 75, 100 e 150 mg L-1 de benzocaína, 25; 37,5; 50 e 62,5 mg L-1 de eugenol e 50, 100, 150 e 200 mg L-1 de mentol a 21°C. Durante o procedimento de anestesia, quatro estágios, da redução dos movimentos operculares até a perda total de reação ao estímulo, foram monitorados. Enquanto anestesiados, os peixes foram submetidos ao processo de biometria e, em seguida, colocados em um aquário com água limpa, sem anestésico, para observação do tempo de recuperação. As concentrações de 75; 37,5 e 150 mg L-1 de benzocaína, eugenol e mentol, respectivamente, foram consideradas ótimas. Por apresentar diversas qualidades como anestésico e poder ser utilizado com eficiência (tempo de anestesia em aproximadamente três minutos e recuperação em menos de cinco minutos) em baixas concentrações, o eugenol apresentou a melhor relação custo benefício para a anestesia de juvenis de robalo-peva.

Comparative effect of benzocaine, menthol and eugenol as anesthetics for juvenile fat snook / Efeito comparativo da benzocaína, mentol e eugenol como anestésicos para juvenis de robalo peva

The present study evaluated different concentrations of benzocaine, eugenol and menthol for induction of anesthesia in juveniles fat snook (Centropomus parallelus), aiming to determine the most suitable product in terms of induction and recovery time, and the minimum optimal dose for each anesthetic. Concentrations of 50, 75, 100 and 150 mg L-1 of benzocaine; 25, 37.5, 62.5 and 50 mg L-1 of eugenol and 50, 100, 150 and 200 mg L-1 of menthol were tested at 21°C. During the procedure of anesthesia, four stages, from reduction of opercular movements to total loss of reaction to stimulus were monitored. While anesthetized, fish were subjected to biometric procedure and then were placed in an aquarium anesthetic free, to observe the recovery time.  Concentrations of 75, 37.5 and 150 mg L-1 of benzocaine, eugenol and menthol, respectively, were considered optimal. By presenting several qualities as an anesthetic and also because it can be used efficiently (time to anesthesia in approximately three minutes and recovery in less than five minutes) at low concentrations, eugenol is the most recommended for anesthesia of juvenile fat snook.

Foram avaliadas diferentes concentrações de benzocaína, eugenol e mentol na indução anestésica em juvenis do robalo-peva (Centropomus parallelus), a fim de determinar o produto mais adequado em termos de tempo de indução e recuperação e o mínimo ótimo de cada anestésico. Foram testadas as concentrações de 50, 75, 100 e 150 mg L-1 de benzocaína, 25; 37,5; 50 e 62,5 mg L-1 de eugenol e 50, 100, 150 e 200 mg L-1 de mentol a 21°C. Durante o procedimento de anestesia, quatro estágios, da redução dos movimentos operculares até a perda total de reação ao estímulo, foram monitorados. Enquanto anestesiados, os peixes foram submetidos ao processo de biometria e, em seguida, colocados em um aquário com água limpa, sem anestésico, para observação do tempo de recuperação. As concentrações de 75; 37,5 e 150 mg L-1 de benzocaína, eugenol e mentol, respectivamente, foram consideradas ótimas. Por apresentar diversas qualidades como anestésico e poder ser utilizado com eficiência (tempo de anestesia em aproximadamente três minutos e recuperação em menos de cinco minutos) em baixas concentrações, o eugenol apresentou a melhor relação custo benefício para a anestesia de juvenis de robalo-peva.

Comparison of the antioxidant defense system in Crassostrea rhizophorae and Crassostrea gigas exposed to domestic sewage discharges.

Oysters Crassostrea rhizophorae and Crassostrea gigas were kept for fourteen days at four sites in São José, SC, Brazil, chosen according to a sewage discharge contamination gradient. Enzymatic activities of CAT, GST, G6PDH and GR were evaluated in gills and digestive glands. Higher CAT activity was observed in tissues of C. rhizophorae in response to sewage contamination possibly indicating peroxisome proliferation induction. C. gigas showed elevated G6PDH activity in digestive gland, and GR in gills, after domestic sewage exposure. In conclusion, C. rhizophorae and C. gigas showed different biochemical responses after in situ exposure to domestic sewage. However, C. rhizophorae showed more significant changes in CAT suggesting that this organism could be a better monitor to this kind of effluent.