The steel industry is a significant worldwide source of atmospheric particulate matter (PM). Part of PM may settle (SePM) and deposit metal/metalloid and metallic nanoparticles in aquatic ecosystems. However, such an air -towater cross -contamination is not observed by most monitoring agencies. The region of Vitoria City is the main location of iron processing for exports in Brazil, and it has rivers, estuaries, and coastal areas affected by SePM. We have evaluated the effects of SePM on a local representative fish species, the fat snook, Centropomus parallelus . After acclimation, 48 fishes (61.67 +/- 27.83 g) were individually exposed for 96 h to diverse levels of SePM (0.0, 0.01, 0.1 and 1 g/L -1 ). The presence of metals in the blood and several blood biomarkers were analyzed to evaluate the impact of SePM on stress signaling, blood oxygen transport capacity, and innate immune activity. Metal bioaccumulation was measured from blood in two separately analyzed compartments: intracellular (erythrocytes plus white blood cells) and extracellular (plasma). The major metals present at all contamination levels in both compartments were Fe and Zn, followed by Al and Cu, plus traces of 'Emerging metals ': Ba, Ce, La, Rb, Se, Sr, and Ti. Emerging metals refer to those that have recently been identified in water as contaminants, encompassing rare earth elements and critical technology elements, as documented in previous studies (See REEs and TCEs in Cobelo-Garc & iacute;a et al., 2015; Batley et al., 2022). Multivariate analysis revealed that SePM had strong, dose -dependent correlations with all biomarker groups and indicated that blood oxygen -carrying capacity had the highest contamination responsiveness. Metal contamination also increased cortisol and blood glucose levels, attesting to increased stress signaling, and had a negative effect on innate immune activity. Knowledge of the risks related to SePM contamination remains rudimentary. However, the fact that there was metal bioaccumulation, causing impairment of fundamental physiological and cellular processes in this ecologically relevant fish species, consumed by the local human population, highlights the pressing need for further monitoring and eventual control of SePM contamination.

The aim of this study was to evaluate the effects of eugenol, benzocaine, and ice water during the sedative, anesthetic or euthanasia processes on the welfare of adult grass carp ( Ctenopharyngodon idella ). The experimental design was randomized and the animals were divided into eight groups. Sixty-two animals underwent an acclimation period. The neutral group used to obtain basal data of grass carp were not subjected to treatments, but anesthetized to collect blood samples and euthanized by medullary section. The others seven groups were submitted to seven treatments with eight repetitions (control group; ethanol; eugenol 50 mgL −1 , eugenol 250 mgL −1 , benzocaine 100 mgL −1 , benzocaine 300 mgL −1 , and ice water 2:1), their behavior was observed. Blood samples was collected and then euthanized by medullary sectioning. Biometric data were measured and a part of the liver was collected for hepatic glycogen analysis. There was a statistically significant difference in the time required to reach the anesthetic stage between the groups ( p < 0.01). Benzocaine and eugenol at the higher concentration provided the fastest responses to sedatives and anesthetics, respectively. The animals subjected to higher anesthetic concentrations reached stage five and did not return from anesthesia, therefore, benzocaine and eugenol were effective euthanizing agents. Benzocaine at the lowest concentration showed the highest concentrations of glucose and cortisol ( p < 0.05). Although benzocaine at 100 mgL −1 concentrations is widely used as an anesthetic in fish, this study demonstrated its use as a stressor agent. Basal data of grass carp for stress parameters are presented for the first time.

Metallic smoke released by steel industries is constitute by a mixture of fine and gross particles containing metals, including the emerging ones, which sedimentation contaminates soil and aquatic ecosystems and put in risk the resident biota. This study determined the metal/metalloids in the atmospheric settleable particulate matter (SePM, particles >10 μm) from a metallurgical industrial area and evaluated metal bioconcentration, antioxidant responses, oxidative stress, and the histopathology in the gills, hepatopancreas and kidneys of fat snook fish (Centropomus parallelus) exposed to different concentrations of SePM (0.0, 0.01, 0.1 and 1.0 g L-1), for 96 h. From the 27 metals (Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Ba, La, Ce, W, Hg, Pb, Bi) analyzed, 18 were quantified in SePM and dissolved in seawater. Metal bioconcentrations differed among organs; Fe and Zn were the metals most bioconcentrated in all organs, Fe was higher in hepatopancreas and Zn > Fe > Sr > Al was higher in kidneys. The activity of superoxide dismutase (SOD) decreased in the gills; SOD, catalase (CAT) decreased, and glutathione peroxidase (GPx) increased in hepatopancreas and, CAT, glutathione-S-transferase (GST) and the level of glutathione (GSH) increased in kidneys. The unchanged levels of lipid peroxidation and oxidized protein in any organ indicate that the antioxidant responses were efficient to avoid oxidative stress. Organ lesion indices were higher in the gills > kidneys > hepatopancreas, being higher in fish exposed to 0.01 g L-1 SePM. All changes indicate a tissue-specific metal/metalloids bioconcentration, antioxidant and morphological responses that all together compromise fish health. Regulatory normative are needed to control the emission of these metalliferous PM to preserve the environment and biota.

This study evaluated the effects of NaCl added to water during silver catfish (Rhamdia quelen) transportation on stress and meat quality. Physiological indicators of stress (cortisol, glucose, circulating ions and liver glycogen) and meat quality parameters (rigor mortis, pH, instrumental color, psychotropic aerobic count and sensory analysis) were assessed. Adult silver catfish (n=380) were distributed in four experimental groups: T1: non-transported; T2: transported without NaCl water addition; T3: transported with 8.0-g NaCl L–1 water addition; T4: transported with 12.0-g NaCl L–1 water addition. The addition of NaCl was not effective at reducing blood cortisol in silver catfish (P>0.05). An osmotic imbalance was detected as an increase in sodium and calcium levels in the NaCl treatment groups. The 12.0-g NaCl L–1 treatment showed rigor mortis evolution in lesser time than the other treatments, and also presented redder meat color. The NaCl addition in transport water do not mitigate the stress in silver catfish, and in high concentrations (12.0-g L–1) was unfavorable for the homeostasis of fish and have negatively affected its meat quality.

Cellular osmoregulation constitutes a phylogenetically conserved set of highly complex responses to changes in external osmolality/tonicity to maintain cell volume, intracellular concentrations of macro- and micromolecules, protein structure and function, and genomic integrity. The successful establishment of the fish species in different habitats and environments depends on its ability to cope with salinity differences between internal (plasma) and external (water) environments through osmoregulation. Although osmoregulation in fishes is mediated by a suite of structures, including the gastrointestinal epithelium and kidney, the gill is the major site of ion movements that balance diffusional gains or losses. Sodium chloride has been used as a mean of stress reduction and increases survival during transportation of freshwater fish in order to balance with water gain and electrolytes losses. Net ionic losses in the urine and diffusional outflux across the gill are balanced by active uptake mechanisms in the gill epithelium plus any ionic gain from food.

The use of anesthetic in fish farming is a traditional practice which aims to reduce the stress caused by transport and handling. However, anesthesia-induction protocols are commonly established and implemented without proper physiological/behavioral evaluation. Additionally, concentration and time of exposure to the anesthetic are often set without considering species-specific responses. The fat snook (Centropomus parallelus) is a fish with great potential for aquaculture. Given its remarkable euryhalinity, it can grow in fresh- or seawater. Most studies on fat snook anesthesia tested natural compounds (essential oils) instead of traditional anesthetics. However, the use of benzocaine is much more common in the commercial sector, as it is easy to obtain and of relatively low cost. The present study aimed at analyzing the effects benzocaine exposure on glucose and cortisol plasma levels (two traditional stress markers in teleost fish), as well as on plasma osmolality, chloride and magnesium, (indicators of osmo-ionic allostasis) in animals acclimated to different salinities. Results showed that while osmo-ionic allostasis was strictly maintained across the treatments, time of anesthesia had a strong positive relationship to plasma cortisol and glucose, regardless the salinity of exposure and acclimation. The results are discussed as they relate to anesthesia protocols and how stress response generated by time of anesthesia may challenge farming flexibility.

The objective of this work was to evaluate fish oil replacement by soybean oil in diets, as for the effects on the performance and body composition of juveniles of fat snook (Centropomus parallelus). The experiment was carried out in a randomized block design, with three treatments (lipid sources) and six replicates, in a 60-day period. Fat snook juveniles (24.17±0.28g) were distributed in 18 experimental tanks of 200 L each, equipped with aeration and heating systems, under continuous water renovation (800% per day). Three isoproteic (44% CP) and isoenergetic (4,635 kcal CE kg-1) diets were formulated to comprise three replacement rates (0, 50, and 100%) of fish oil by soybean oil. Biometric analyses were done to evaluate fish performance, and two entire specimens from each replicate were used for body composition analyses. The zootechnical indices of weight gain (38.68±5.41 g), feed conversion (1.38±0.10), and specific growth at 1.70±0.18% weight gain per day were considered satisfactory. Lipid source substitution does not affect the performance and body composition of fat snook juveniles, which suggests that soybean oil can replace fish oil in diet formulation.

O objetivo deste trabalho foi quantificar o crescimento de juvenis de robalo-peva (Centropomus parallelus) cultivados em diferentes temperaturas. Os peixes foram cultivados durante 49 dias, a 20, 23, 26 e 29ºC. A temperatura da água influenciou o ganho de peso. Os peixes criados a 26 e 29ºC apresentaram os maiores ganhos em peso e foram os mais eficientes na conversão alimentar. Os peixes cultivados a 29ºC também apresentaram melhores taxas de crescimento específico. O desempenho do robalo-peva é afetado a 20ºC, e a espécie deve ser cultivada em temperaturas superiores a 23ºC.

This study verified the effects of CaSO4 on physiological responses of the tropical fish matrinxaBrycon amazonicus (200.2 +/- 51.1 g) in water containing CaSO4 after a 4-h transportation at concentrations of: 0, 75, 150, and 300 mg L-1. Blood samples were collected prior to transportation (initial levels), immediately after packaging, at arrival, and 24 h and 96 h after transportation (recovery). Cortisol levels increased after packaging (118.2 +/- 14.2 ng ml(-1)), and decreased slightly after transportation in water containing CaSO4 (106.8 +/- 14.1), but remained higher than initial levels (21.0 +/- 2.6 ng ml(-1)). Fish kept at 150 mg L-1 CaSO4 reached the pre-transportation levels at 24 h of recovery. Blood glucose increased after transportation in all treatments (8.2 +/- 0.2 mmol L-1) and declined after full recovery to values below initial levels (4.8 +/- 0.1 mmol L-1). Chloride levels did not change in CaSO4 treatments; serum sodium concentrations decreased after packaging and after transportation. Serum calcium levels did not differ among treatments, but decreased after packaging and increased at 96 h of recovery. Hematocrit and the number of red blood cells were higher in all treatments after packaging and arrival, except in fish exposed to 300 mg L-1 CaSO4. Mean corpuscular volume increased in 75 mg L-1 CaSO4, which reached the higher VCM after transportation. Hemoglobin levels increased only after transportation, regardless of calcium sulfate levels. Handling before transportation and transportation itself were both stressful to fish; calcium sulfate at concentrations tested in the present work had a moderate influence in the reduction of stress responses.

A pesca vem apresentando dados de estabilização nas taxas de captura em todo o mundo, apesar do aumento do esforço com desenvolvimento de tecnologias. Essa tendência tem levado o pescador artesanal a buscar outras opções de sustento. Este artigo apresenta a maricultura destacando espécies nativas como a ostra (Crassostrea sp.) e o robalo peva (Centropomus parallelus). O cultivo dessas espécies é uma alternativa de atividade sustentável em ambientes estuarinos, onde é realizada a maior parte da pesca artesanal. São apresentados exemplos de cultivos produtivos e experimentais das espécies adaptadas ao ambiente estuarino e que apresentam demanda pelo consumidor, habituado a adquirir esses produtos.

Pacu juveniles (5.2 ± 1.5 g) were submitted to two one-minute air exposures in a 24 h interval, and sampled before the exposure (control) and 5, 15, 30 and 60 min, 24 and 48 h afterwards for whole-body cortisol, sodium, potassium and calcium ion concentrations. For the first air exposure, there was a trend of increased cortisol concentration after 15 min, whereas in the second air exposure, the cortisol concentration increased significantly within 5 min after stress was induced. Sodium ion concentration increased significantly 24 h after both air exposures. Potassium concentration presented fluctuations over the experimental period. Calcium ion concentration increased progressively from 5 to 30 min, in both air exposures. The repeated air exposures exacerbated the cortisol response, but they did not affect the recovery ability of pacu over the experimental period. Additionally, the whole-body cortisol measurement might be a reliable indicator of stress, when sampled fish are smaller and blood volumes are very low, making samples inadequate for analysis

O marcador molecular RAPD vem sendo amplamente empregado em análises moleculares,proporcionando grandes avanços aos estudos de avaliação da estrutura genética entre populações de umagrande variedade de organismos. Entretanto, determinadas limitações diretamente associadas à extraçãode DNA genômico e às condições de amplificação costumam restringir seu emprego. Nesse contexto, opresente estudo teve como objetivo estabelecer protocolos de otimização de reações de amplificaçãoaleatória de DNA polimórfico a partir de amostras de tecidos isoladas de Centropomus parallelus a fim deassegurar maior reprodutibilidade e alto poder discriminatório dessa técnica. Um perfil eletroforéticoaltamente variável foi detectado nas reações de amplificação aleatória do DNA genômico de robalopeva, sendo observados produtos amplificados com alta nitidez e tamanhos variando entre 100 a 3.000pb. Os produtos de RAPD-PCR produziram um padrão de bandas altamente monomórfico, quando osprimers AM13, OPW5 e OPA20 foram testados. Entretanto, consideráveis variações no tamanho e númerode bandas amplificadas foram observadas apenas nas reações realizadas na presença do primer OPX4. Asdescobertas apresentadas no presente estudo descrevem o estabelecimento de determinados procedimentosexperimentais a fim de viabilizar os ensaios de amplificação arbitrária a partir de amostras de DNAgenômico de robalo peva C. parallelus por análises de RAPD. Tais descobertas criam reais possibilidadespara o uso da técnica de RAPD-PCR como ferramenta auxiliar nas análises de variabilidade e diversidadegenética entre populações de robalo peva C. parallelus, possibilitando futuramente o desenvolvimento dediferentes trabalhos genético-moleculares empregando tal procedimento experimental.

O conhecimento da proporção da matéria-prima que será transformada em produtos finais para comercialização, bem como da quantidade que fará parte do resíduo do processamento permite o planejamento logístico da produção e os cálculos necessários para a avaliação da eficiência produtiva da empresa processadora de pescado. O jundiá Rhamdia quelen é um bagre nativo da América do Sul e que vem sendo estudado há alguns anos por vários grupos de pesquisa latino-americanos, apresentando resultados que atestam seu potencial para a piscicultura. O objetivo do presente trabalho foi avaliar o rendimento do jundiá como matéria-prima para o processamento mínimo em diferentes classes de pesos, a saber: 200 – 300 g, 301 – 400 g, 401 – 500 g, 501 – 600 g, 601 – 700 g, 701 – 800 g. Devido ao crescimento mais acelerado das fêmeas, apenas indivíduos do sexo feminino foram encontrados nas classes de peso acima de 500 g. O rendimento de filé foi maior para os peixes com maior peso médio (728g - 34,7%). A porcentagem de músculo abdominal esteve entre 9,3% e 11,2%. A proporção de vísceras sem as gônadas encontrou-se entre 7,8 e 9,8% e a porcentagem de gônadas das fêmeas com peso médio 572 g representou 11,1% do peso total. A descrição da composição da carcaça dos peixes cultivados tem grande importância sob o aspecto econômico e produtivo, permitindo estimativas de produtividade tanto para o piscicultor quanto para a indústria de processamento.

* Corresponding author <carneiro@rla01.pucpr.br> ABSTRACT: Live diet (LD) dependence and the lack of suitable formulated diets (FD) are major constraints for the expansion of larviculture of many fish species. The low digestibility and nutritional quality of FD are factors that might explain their failure as a stand-alone starter food. To determine whether FD in combination with LD (zooplankton) may efficiently increase larval growth and survival of jundiá (Rhamdia quelen), when compared to fish fed by either types of diet alone, jundiá larvae (5.57 mm; 1.41 mg) were initially stocked into 12 10-L aquaria (100 larvae per aquarium). Replicate groups (n=4) were fed ad libitum one of the three diets for 20 (when fed FD) or 48 days (when fed LD or the combined diets). Larvae fed FD alone presented significantly lower survival and growth rates as compared to larvae fed LD or a combination of both (co-fed). In addition, co-fed larvae grew better (170 mg) in relation to those fed solely with LD (110 mg). Such better performance of combined feeding indicates that most of the required nutrients are in balance when both diet sources are included. More can be learned about fish larvae nutrition by further testing the effect of feeding combined diets, which include zooplankton, than only testing new ingredients or protein sources commonly used in the elaboration of juvenile or adult fish feeds.

Live diet (LD) dependence and the lack of suitable formulated diets (FD) are major constraints for the expansion of larviculture of many fish species. The low digestibility and nutritional quality of FD are factors that might explain their failure as a stand-alone starter food. To determine whether FD in combination with LD (zooplankton) may efficiently increase larval growth and survival of jundiá (Rhamdia quelen), when compared to fish fed by either types of diet alone, jundiá larvae (5.57 mm; 1.41 mg) were initially stocked into 12 10-L aquaria (100 larvae per aquarium). Replicate groups (n=4) were fed ad libitum one of the three diets for 20 (when fed FD) or 48 days (when fed LD or the combined diets). Larvae fed FD alone presented significantly lower survival and growth rates as compared to larvae fed LD or a combination of both (co-fed). In addition, co-fed larvae grew better (170 mg) in relation to those fed solely with LD (110 mg). Such better performance of combined feeding indicates that most of the required nutrients are in balance when both diet sources are included. More can be learned about fish larvae nutrition by further testing the effect of feeding combined diets, which include zooplankton, than only testing new ingredients or protein sources commonly used in the elaboration of juvenile or adult fish feeds.A larvicultura da maioria das espécies de peixes enfrenta o desafio da dependência do alimento vivo (AL) e da falta de dietas formuladas (DF) que atendam plenamente às necessidades das larvas. A baixa digestibilidade e a qualidade nutricional das DFs são alguns dos fatores que explicam o insucesso quando as larvas recebem apenas FD. Para avaliar o efeito da combinação da DF com o AL no crescimento e na sobrevivência de larvas de jundiá (Rhamdia quelen), comparando com o uso separado da DF ou do AL, larvas recém eclodidas (5,57 mm; 1,41 mg) foram estocadas inicialmente em 12 aquários de 10 L (100 larvas por aquário). Quatro réplicas foram alimentadas ad libitum com uma das três dietas por 20 (para DF) ou 48 dias (para AL ou a combinação DF + AL). As larvas alimentadas com apenas DF apresentaram crescimento e sobrevivência reduzidos quando comparadas àquelas alimentadas com AL ou a combinação DF + AL. Adicionalmente, as larvas do tratamento DF + AL apresentaram maior crescimento em peso (170 mg) que aquelas alimentadas apenas com AL (110 mg). O melhor desempenho das larvas alimentadas com DF + AL mostra que a maioria dos nutrientes exigidos pelas larvas é fornecida mais adequadamente quando ambas as dietas são fornecidas juntamente. Contudo, trabalhos sobre nutrição larval poderão contribuir ainda mais sobre a elucidação deste tema quando feitas comparações com o uso combinado de DF + AL, do que apenas testando isoladamente novos ingredientes e fontes protéicas normalmente utilizadas na elaboração de dietas para juvenis e adultos.

No Brasil, aproximadamente quatro milhoes de pessoas estao envolvidas direta ou indiretamente com a aquicultura, a qual contribui como fonte de renda e producao de alimento. Na ultima decada, o consumo per capita de pescado no mundo elevou-se exponencialmente, ressaltando a preocupacao quanto ao bem-estar e reducao do estresse desses animais por parte do consumidor de proteina animal, dos pesquisadores, dos desenvolvedores de tecnologias ou dos produtores. E sabido que o estresse nos peixes desencadeia respostas neuroendocrinas, gerando respostas primarias, secundarias e/ou terciarias, que liberam catecolaminas e cortisol, prejudicial para o desenvolvimento, imunidade e reproducao. A senciencia e o pilar de sustentacao dos estudos que envolvem o bem-estar animal e os peixes sao seres sencientes. Desta forma, novas pesquisas objetivando a diminuicao do estresse e sofrimento; visando boas praticas de manejo destes animais sao essenciais para que se possa definir tecnicas adequadas e humanitarias de abate.