In vitro mucus transportability, cytogenotoxicity, and hematological changes as non-destructive physiological biomarkers in fish chronically exposed to metals.

The biomonitoring of fish using biomarkers represents a useful tool for the assessment of aquatic pollution. This study evaluated the sublethal toxic effects of aquatic pollution on fish collected from a site contaminated by metals. Water and fish (Oreochromis niloticus) samples were collected from a pond in the Parque Ecológico do Tietê (PET) that lies along the Tietê River (São Paulo, Brazil), and from a control site (an experimental fish farm). The metal content of the water was evaluated, and fish were used to examine the properties of gill mucus and blood. The PET fish were evaluated for alterations in the in vitro transportability of mucus and changes in blood properties (e.g., cell volume, hemoglobin concentration, red blood cells, and white blood cell count). The results of the water analyzes indicated metal levels above the legal standards for Fe (0.71 mg/L), Ni (0.06 mg/L), Mn (0.11 mg/L), and Pb (0.48 mg/L). Compared to the controls, the hematologic parameter analyzes of PET fish revealed significantly higher numbers of erythrocytes (RBC), leukocytes (WBC), lymphocytes, erythroblasts, and Mean Corpuscular Volume (MCV); however, the hemoglobin content and Mean Corpuscular Hemoglobin Concentration (MCHC) values were significantly lower. The frequencies of nuclear abnormalities and micronuclei were significantly higher and the mucociliary transport was significantly lower in PET fish than in the controls. These results suggest that fish from the contaminated site exhibit a series of physiological responses, which probably indicate health disturbances. Furthermore, the results suggest that blood and mucus are promising, non-destructive targets for use in the monitoring of pollution.

Occurrence of parasitism by Dioctophyma renale in ring-tailed coatis (Nasua nasua) of the Tiete Ecological Park, São Paulo, Brazil / Ocorrência de parasitismo por Dioctophyma renale em quati (Nasua nasua) do Parque Ecológico Tietê, São Paulo

Dioctophymosis is a worldwide renal parasitosis caused by the Dioctophyma renale nematode, which results in progressive destruction of renal tissue. Aquatics annelids are considered the main intermediate hosts and the literature refers as permanent hosts of dogs, wild mammals and even humans. During procedures for population control of coatis (Nasua nasua) in the Ecological Park of Tietê (PET), was noticed the presence of parasitosis by D. renale. From 68 animals, males and females, young and adults, submitted to exploratory laparotomy, 51 were positive for the presence of worms, 9 were found only in the right kidney. In 10 cases, in addition to right kidney parasitism, worms were also observed in the abdominal cavity. In 24 cases D. renale was found only in the abdominal cavity and in 8 animals the right kidney was reduced to a small rigid structure. The study showed that the preferred site for parasitism of the worm, considered erratic, was the abdominal cavity in 66.66 percent of the cases.

A dioctofimose é uma parasitose renal causada pelo nematóide Dioctophyma renale conhecida por gerar a destruição progressiva do parênquima renal. Anelídeos de água doce são considerados os principais hospedeiros intermediários e a literatura refere como hospedeiros definitivos cães domésticos, mamíferos selvagens e até seres humanos. Durante procedimentos de controle populacional de quatis (Nasua nasua) no Parque Ecológico do Tietê (PET), evidenciou-se a presença do parasitismo por D. renale. Sessenta e oito animais foram submetidos à laparotomia, machos e fêmeas, jovens e adultos, dos quais 51 foram positivos para presença do parasita. Em 9 animais o parasita esteve presente apenas no rim direito; em 10 animais D. renale parasitava o rim direito e a cavidade abdominal simultaneamente. Em outros 24 quatis o parasita foi encontrado apenas na cavidade abdominal e em 8 animais o rim direito foi reduzido apenas a uma pequena estrutura rígida. O estudo demonstrou que para este hospedeiro (Nasua nasua), o rim direito não parece ser local de escolha do parasita, já que o encontro do verme em 66,6 por cento dos casos foi a cavidade abdominal.