Low Dose of the Anesthetic Propofol Does Not Induce Genotoxic or Mutagenic Effects in Nile Tilapia

We demonstrate the efficacy of propofol (2,6-diisopropylphenol) as an anesthetic when administered to fish in an immersion bath and show the absence of genetic side effects following short-term exposure to the drug. All tested fish were anesthetized (as indicated by loss of posture and lack of response to physical stimulation), and both the comet assay (tail intensity) and the micronucleus assay revealed that propofol does not induce primary DNA damage or chromosome damage in the fish Nile Tilapia Oreochromis niloticus. Our results should be considered in light of our particular test conditions, including the water temperature (similar to 25 degrees C), the life stage and size of the fish, and the single exposure to the anesthetic. We suggest that propofol is a promising anesthetic in terms of its lack of genotoxic effects, at least in low dosages in adult Nile Tilapia.Received June 25, 2013; accepted October 15, 2013

Microbiological quality of whole and filleted shelf-tilapia

Despite fish being a rich source of animal nutrients and having numerous associated health benefits, it is an extremely perishable food, prone to a wide range of hazards. The bacterial load associated with shelf-whole-fish organs (e.g. digestive tracts and skin) or mishandling of fish may be a vehicle of infection and become a risk to public health. The objective of this paper is to evaluate the microbiological quality of whole ungutted and filleted shelf-tilapia, as well as assess the safety for human consumption. For this purpose, in order to investigate the distribution and occurrence of bacterial populations, the count of total and thermotolerant coliforms, coagulase-positive Staphylococcus and presence of Salmonella spp. was determined. This paper shows that all fish organs were contaminated with thermotolerant coliform. Skin and fillet show higher populations and occurrence of all microorganisms analyzed. Lower bacterial populations were recovered from the gut and muscles of whole tilapia. Two samples of fillet were contaminated with coagulase-positive Staphylococcus. It can be concluded that the skin and filleted tilapia are important carriers of food-borne pathogens. In addition, fish might become an important cross and self-contamination source. (C) 2014 Elsevier B.V. All rights reserved.

Sugar cane vinasse in water bodies: Impact assessed by liver histopathology in tilapia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Non-specific immune parameters and physiological response of Nile tilapia fed beta-glucan and vitamin C for different periods and submitted to stress and bacterial challenge

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoperiod modulation of aggressive behavior is independent of androgens in a tropical cichlid fish

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Social instability promotes hormone-behavior associated patterns in a cichlid fish

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Substratum choice for nesting in male Nile tilapia Oreochromis niloticus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Social Stability Related to Sex Group Composition in the Cichlid Nile Tilapia

Aquaculture practices usually put the Nile tilapia in an artificial social environment, which males predominate due to their faster growth desirable for aquaculture purposes. Such a situation can increase male-male fighting because males are generally more aggressive than females, and also because fighting ability is similar within the same sex, leading to longer contests. As behavior has been used to infer welfare in several fish species, the aim of this study was to investigate whether sex composition affects agonistic interactions, social hierarchy and energetic demand in groups of Nile tilapia (Oreochromis niloticus; L.). Size-matched adult fish were divided in two treatments: MM = four males and MF = two males and two females (10 repetitions for each treatment). The experiment lasted for 11 days and social interactions (aggressiveness and rank order) were recorded at the 2nd, 6th and 10th days (15 min per day). Fish were food deprived and body weight loss was used to infer energetic cost. A higher frequency of lateral threat (Student’s t independent test; t = 2.55; p = 0.02) and total interactions (Student’s t independent test; t = -2.81; p = 0.01) was observed in the MF treatment. MM group showed unstable hierarchy (Binomial test, p = 0.04), which is considered a social stressor. However, mean weight loss was not affected by treatments (Student’s t independent test; t = -0.74; p = 0.47). These results support the idea that sexual composition affects aggressive interactions and destabilizes social hierarchy, but not energy cost

The stream fish fauna from three regions of the Upper Paraná River basin

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Integrated multi-trophic culture of Nile tilapia (Oreochromis niloticus) and Amazon river prawn (Macrobrachium amazonicum) in brackish water

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ecological carrying capacity for intensive tilapia (Oreochromis niloticus) cage aquaculture in a large hydroelectrical reservoir in Southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Anti-androgenic activities of diuron and its metabolites in male Nile tilapia (Oreochromis niloticus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Prevalence of ectoparasites and bacteriological diagnosis in Nile tilapia bred in net-tanks in the Corvo's river, Parana, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Haematology and histopathology of Nile tilapia parasitised by Epistylis sp., an emerging pathogen in South America

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hematological changes and cytogenotoxicity in the tilapia Oreochromis niloticus caused by sub-chronic exposures to mercury and selenium

Fish bioassays are valuable tools that can be used to elucidate the toxicological potential of numerous substances that are present in the aquatic environment. In this study, we assessed the antagonistic action of selenium (Se) against the toxicity of mercury (Hg) in fish (Oreochromis niloticus). Six experimental groups with six fish each were defined as follows: (1) control, (2) mercury (HgCl2), (3) sodium selenite (Na2Se4O3), (4) sodium selenate (Na2Se6O4), (5) mercury + sodium selenite (HgCl2 + Na2Se4O3), and (6) mercury + sodium selenate (HgCl2 + Na2Se6O4). Hematological parameters [red blood cells (RBC), white blood cells (WBC), and erythroblasts (ERB)] in combination with cytogenotoxicity biomarkers [nuclear abnormalities (NAs) and micronuclei (MN)] were examined after three, seven, ten, and fourteen days. After 7 days of exposure, cytogenotoxic effects and increased erythroblasts caused by mercury, leukocytosis triggered by mercury + sodium selenite, leukopenia associated with sodium selenate, and anemia triggered by mercury + sodium selenate were observed. Positive correlations that were independent of time were observed between WBC and RBC, ERB and MN, and NA and MN. The results suggest that short-term exposure to chemical contaminants elicited changes in blood parameters and produced cytogenotoxic effects. Moreover, NAs are the primary manifestations of MN formation and should be included in a class characterized as NA only. Lastly, the staining techniques used can be applied to both hematological characterization and the measurement of cytogenotoxicity biomarkers.