Maria José Tavares Ranzani-Paiva

Cytogenotoxicity biomarkers in fat snook Centropomus parallelus from Cananéia and São Vicente estuaries, SP, Brazil

The aquatic environment receives many contaminants that can induce damages at the molecular, biochemical, cellular and physiological levels. Centropomus parallelus, an important food resource for local populations, is a predator fish that feeds on small fishes and benthic invertebrates, thus being vulnerable to the bioconcentration and biomagnification processes. This study aimed to evaluate cytogenotoxic responses in erythrocytes from C. parallelus juveniles collected in the Cananéia and São Vicente estuaries, both in winter and in summer. After anesthesia, blood samples were collected by caudal puncture. Blood smears were prepared on glass slides and stained with May-Grünwald-Giemsa dye. Two thousand cells were analyzed per slide (1000x), and nuclear abnormalities (NA) and micronuclei (MN) were scored. The São Vicente sample showed MN and NA frequencies (%/1000 cells) of 0.325 and 3.575, in winter, and of 0.125 and 2.935 in summer respectively; the Cananéia sample showed frequencies of 0.0325 and 0.03, in winter, and of 0.065 and 0.355 in summer, respectively. The rates found in São Vicente were significantly higher than those found in Cananéia, evidencing that the levels of pollution in that estuary were high enough to induce genetic damages.

Histopathologic changes in the kidney tissue of Prochilodus lineatus Valenciennes, 1836 (Characiformes, Prochilodontidae) induced by sublethal concentration of Trichlorfon exposure

Neste trabalho foram avaliadas as alteracoes histopatologicas no tecido renal de curimbata Prochilodus lineatus, atraves de bioensaio agudo provocado pela contaminacao da agua por 0,2ml/litro de solucao de Dipterex 500 (Trichlorfon) diluido em solucao aquosa. Alteracoes comportamentais dos peixes pertencentes ao grupo contaminado, foram observadas a partir de 24 horas apos o inicio da exposicao. O tecido renal coletado apos 24 horas de exposicao apresentou aumento do espaco intercapsular com glomerulos atroficos, hipertrofia das celulas dos tubulos renais, extravasamento sanguineo a partir de capilares e areas de necrose. Apos 48 horas o tecido renal apresentou dilatacao glomerular, perda do conteudo celular do epitelio capsular parietal e da membrana basal, inchaco, vacuolizacao e granulacoes finas e grossas no citoplasma das celulas tubulares e focos de necrose acentuada.

Hematological parameters in Nile Tilápia, Oreochromis niloticus exposed to sub-letal concentrations of mercury

Mercury toxicity in tilapia, Oreochromis niloticus, (Linnaeus, 1758) was investigated by the hematological parameters after long-term (14 days) exposure to various Hg concentrations (0.02, 0.002, 0.0002mg/L Hg). Test groups were set up with three replicates for each concentration, plus the control group. Blood samples were collected from six individuals for each concentration at 0, 3, 7, 10 and 14 days of exposure. The hematological parameters analyzed were: total red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total white blood cell count (WBC) and differential leukocyte counts and total thrombocyte count (Tr). There were no significant differences among the mean hematological values at the different Hg concentrations indicating that Hg at the concentrations studied was not toxic to tilapia.

Influence of seasonality and pollution on the hematological parameters of the estuarine fish Centropomus parallelus

No presente estudo, foram utilizados parâmetros hematologicos do peixe tropical estuarino Centropomus parallelus como biomarcador nao destrutivo. Os peixes foram coletados, no verao e no inverno, em dois estuarios: Cananeia (CAN) e Sao Vicente (SVE). Foram analisados: hematocrito (Ht), contagem de eritrocitos (RBC), volume corpuscular medio (VCM), leucograma (WBC) e trombograma. Os peixes de ambos locais apresentaram variacoes no quadro hematologico devido a sazonalidade e aos niveis de degradacao ambiental. Os peixes de Cananeia apresentaram aumento no numero absoluto de trombocitos no verao, enquanto aqueles coletados em Sao Vicente apresentaram hematocrito (Ht) e Volume Corpuscular Medio (MCV) menor no inverno. Comparando o quadro hematologico dos peixes dos dois estuarios, observamos maiores valores de hematocrito (Ht), Volume Corpuscular Medio (MCV), leucocitos (WBC), e numero de eritrocitos (RBC) nos peixes de Sao Vicente no verao, enquanto no inverno, Ht e trombocitos foram tambem maiores nos peixes desse local. Os resultados sugerem que as alteracoes observadas no quadro hematologico se deveram a qualidade ambiental dos estuarios e a sazonalidade.

Profile of cortisol, glycaemia, and blood parameters of American Bullfrog tadpoles Lithobates catesbeianus exposed to density and hypoxia stressors

The aim of this study was to evaluate alterations to the physiological profile (cortisol, glycaemia, and blood parameters) of Lithobates catesbeianus caused by the stressors density and hypoxia. The organisms were in the prometamorphosis stage and exposed to different tadpole densities: 1 tadpole/L (T1), 5 tadpoles/L (T2), and 10 tadpoles/L (T3) for 12 days. The blood was collected through the rupture of the caudal blood vessel and collected under normoxia (immediate collection) and hypoxia (after 15 minutes of air exposure) conditions. Cortisol levels rose on the fourth and eighth days of treatment and returned to basal levels by the end of the experiment. The stressor mechanisms tested did not affect glycaemia. White blood cells (total number of lymphocytes, neutrophils, and eosinophils) showed a significant difference at the twelfth day of the experiment when compared with the start of the experiment. We concluded that, under controlled conditions, a density of up to 10 tadpoles/L and air exposure for 15 minutes did not cause harmful physiological alterations during the experimental period. The answer to these stressors maybe was in another hormonal level (corticosterone).

Hematological analysis of Micropogonias Furnieri, Desmarest, 1823, Scianidae, from two estuaries of Baixada Santista, São paulo Brazil

Hematological alterations in fish are considered a useful tool to evaluate pathological processes resulting from the exposure to environmental pollutants. The whitemouth croaker Micropogonias furnieri is a common species in estuarine areas and potentially exposed to many contaminants. In the present study, the hematological characteristics of fish collected at two sites in Baixada Santista (Santos Estuarine System - SES, a polluted site; and the Estuary of Itanhaem River - EIR, unpolluted site) del was analysed. The following blood descriptors were analyzed: number of Erythrocytes (Er), Hematocrit (Ht), Hemoglobin (Hb), Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin concentration (MCHC). Fish from SES exhibited significant lower levels of Ht and increase on MCHC and Hb. Such differences are likely related to the different contamination levels found in these estuaries.

Teflubenzuron as a tool for control of trichodinids in freshwater fish: Acute toxicity and in vivo efficacy

In this study we describe the anti-Trichodina effects of teflubenzuron (TFB) for Oreochromis niloticus and for Piaractus mesopotamicus. We also evaluated the acute toxicity, for both species, by using TFB in the concentrations of 700.0, 800.0, 900.0 and 1000.0 mg L(-1) and a control, without the drug. To assess the efficacy of TFB against Trichodina spp., we used the concentrations of 30.0 or 50.0 mg L(-1) for one hour exposure in tilapia, and the concentration of 30.0, 50.0 and 80.0 mg L(-1) for one hour and 50 mg L(-1) for two hours exposures in pacu. Teflubenzuron did not present significant toxicity in either species, with LC50;48h > 1000.0 mg L(-1). The drug effectiveness was observed against four identified Trichodina species: T. magna, T. heterodentata, T. compacta and T. centrostrigeata, with 87.9% parasite reduction with one hour exposure to 50.0 mg L(-1) TFB on O. niloticus and 96.1% with two hours exposure to 50.0 mg L(-1) TFB on P. mesopotamicus. Teflubenzuron is a drug with potential to be used in Brazilian aquaculture; it attends to important requirements, such as low toxicity and high efficacy in controlling Trichodina spp. infection in O. niloticus and P. mesopotamicus.

Fish pathogen bacteria: Adhesion, parameters influencing virulence and interaction with host cells

&NA; Wild fisheries are declining due to over‐fishing, climate change, pollution and marine habitat destructions among other factors, and, concomitantly, aquaculture is increasing significantly around the world. Fish infections caused by pathogenic bacteria are quite common in aquaculture, although their seriousness depends on the season. Drug‐supplemented feeds are often used to keep farmed fish free from the diseases caused by such bacteria. However, given that bacteria can survive well in aquatic environments independently of their hosts, bacterial diseases have become major impediments to aquaculture development. On the other hand, the indiscriminate uses of antimicrobial agents has led to resistant strains and the need to switch to other antibiotics, although it seems that an integrated approach that considers not only the pathogen but also the host and the environment will be the most effective method in the long‐term to improve aquatic animal health. This review covers the mechanisms of bacterial pathogenicity and details the foundations underlying the interactions occurring between pathogenic bacteria and the fish host in the aquatic environment, as well as the factors that influence virulence. Understanding and linking the different phenomena that occur from adhesion to colonization of the host will offer novel and useful means to help design suitable therapeutic strategies for disease prevention and treatment. Graphical abstract Figure. No Caption available. HighlightsFish bacterial diseases are an important problem in aquaculture.New approaches considering the interaction between the pathogen, the host and the environmental parameters are priority.Linking bacterial adhesion and fish cell responses will help to design suitable therapeutic strategies.

BULLFROG HEMOGRAM UNDER MANAGEMENT STRESS

Stress is one of the major obstacles in frog culture and can be caused by factors such as inappropriate farming systems; inadequate management among other situations. The objective of the present study was to assess the hemogram, erythrogram and leukogram of bullfrogs (L. catesbeianus) when exposed to stress caused by different types of management: density and handling (manipulation), developed in the laboratory and repeated in the field for the appropriate comparisons in a experimental period of 30 days. The density experiment was conducted with four treatments: 70 animals m-2 (D70); 100 animals m-2 (D100), Control; 150 animals m-2 (D150) and 200 animals m-2 (D200), with 10, 14, 21 and 28 animals/box in the laboratory, respectively. Each treatment was performed with three simultaneous replicates. The handling experiment was conducted with three treatments: Treatment Without Handling (WH); Treatment with Partial Handling (PH) every 15 days and Treatment with Total Handling (TH) every 15 days. Each treatment was performed with four simultaneous replications. The methodology of the blood analysis followed international recommendations. In the present study we could observe that the animals of the field experiment did not reflect the same stress response observed in the laboratory in both experiment, which demonstrated the plasticity of these animals.