ABSTRACT: Several microalgae contain in excess of 50 % crude protein with amino acid profile comparable to that of fish meal. In addition, high polyunsaturated fatty acid contents encourage their use in animal feeding and nutrition, particularly in the formulation and processing of aquafeeds. This study aims at estimating the feasibility of Chlorella meal as feed ingredient for the feeding and nutrition of farmed tilapia based upon digestibility data. Juvenile tilapia were stocked in conical-bottomed tanks (200 L) with superficial, continuous water flow, and fed to apparent satiation in three daily meals with a reference diet and a test diet containing 30 % lyophilized Chlorella sorokiniana added of an inert marker. Feces were collected overnight by sedimentation in refrigerated, plastic containers coupled to the tanks and analyzed for determination of chemical composition and inert marker contents to estimate apparent digestibility coefficients (ADCs) of protein and energy of Chlorella meal; registered ADCs of Chlorella meal were 90.5 and 84.22, respectively. A pricing model considering the quantity of digestible nutrient was proposed based on ADCs of Chlorella and compared with the price of fishmeal (FM) and soybean meal (SBM). The indicative prices to elicit the use of Chlorella as a protein source rather than FM or SBM for the feed and nutrition of tilapia were 2.65 USD kg−1 and 0.66 USD kg−1, respectively.

ABSTRACT: Along the last ten years fish and fishery product trade in Brazil has been on a downward trajectory turning a profit of US$ 98.6 million in 2005 into a loss of US$ 1.25 billion by 2014. On the other hand, the country is a leading producer of grains and has the third largest animal feed industry in the world, which has added 5.5 million hectares of freshwater reservoirs and 3.5 million km2 of an exclusive marine economic zone in the same period, a sizable potential for development of the aquaculture industry. This study aims at unveiling strategies for the reduction of the deficit in the Brazilian seafood trade balance, based on critical analysis of the quantitative and qualitative characteristics of imported fishery products. The fish and fishery product trade in Brazil, from 2005 to 2015, was studied considering import and export data mined from the Brazilian Ministry of Development, Industry and Commerce databases through the Aliceweb system, and clustered as follows: processing; product species; origin; conservation; and group. The main imported products were gutted fresh fish, highest price (salmon); salted dried fish, higher price (cod); frozen fish fillets, lowest price (fish and hake). The replacement of fish imports by domestic production is not enough to enable consumers to identify the equivalence between products (technical, qualitative or organoleptic). Developing strategies for the production of fish and fishery products at competitive prices and quantities that meet consumer demand is an immediate need, and the development of the aquaculture industry a rational strategy.

ABSTRACT Prolonged stress hampers immune function and lessens disease resistance of fish, causing economic losses. Attention is thus been centered in the study of fish immunology. The main ‘in vivoʼ models used in immunological studies are: stimulation of immune response (by immunostimulant molecules); induction of inflammation; induction of immunosuppression by chronic stress; or administration of drugs. This trial aimed at evaluating existing protocols for immunosuppression by drugs in fish, adapted to slow release implants model, using hydrogenated vegetable fat (HVF), with the intention of set a controlled immunodeficiency state model for advanced studies. The implant model was not efficient in reducing the immune response in a controlled manner. Evidence of self, down-regulation in fish immune system was found in implanted fish, what should be further investigated using molecular tools.

El objetivo de este estudio fue el de evaluar el efecto de la inclusion de aditivos en el agua durante el transporte de pacu (Piaractus mesopotamicus) en estado juvenil sobre la sobrevivencia de los peces una vez transferidos y mantenidos en jaulas de cultivo. Ochocientos peces de 30 ± 1,75 g/ pez fueron mantenidos en ayuna por 24 h y luego distribuidos al azar en 20 bolsas de plástico de 30 l (40 peces por bolsa). Cada bolsa fue dispuesta en un recipiente plástico. Los peces fueron transportados por 2 h. Los aditivos y concentraciones usadas en el presente estudio fueron: sal (8 g/l), florfenicol (0,01 g/l), oxitetraciclina (0,001 g/l), y una combinación de sal (8 g/l) + yeso (1 g/l). Un tratamiento control (no aditivos) fue incluido en el estudio. Parámetros de calidad del agua tales como el oxígeno disuelto, la saturación de oxígeno, pH, temperatura, nitrito y amoniaco fueron medidos al principio y al final del periodo de tranporte. El uso de aditivos en el agua durante el transporte del pacu no mostró un efecto sigificativo (P>0,05) sobre la mortalidad de los peces mantenidos en jaulas de cultivo. Los resultados del presente estudio destacan la ineficiencia de la adición de estos compuestos en el agua durante el transporte del pacu.

The aim of this study was to assess the effect of the inclusion of additives into the water during transportation of juvenile pacu (Piaractus mesopotamicus) on the survival rate of fi sh once they are transferred and stocked in cages. Eight hundred fi sh of approximately 30 ± 1.75 g/fi sh of body weight were fasted for 24 h and then distributed into 20 plastic bags of 30 l (40 fi sh per bag). Each bag was then placed in a plastic container. The transportation period lasted for 2 h. The additives and concentrations used in the present study were: salt (8 g/l), fl orfenicol (0.01 g/l), oxytetracycline (0.001 g/l) and a combination of salt (8 g/l) + gesso (1 g/l). A control treatment (with no addition of additives) was included in the study. Water quality parameters such as dissolved oxygen, oxygen saturation, pH, temperature, nitrite and ammonia were measured at the beginning and at the end of the transportation process. The use of additives in the water during transportation of pacu did not have a signifi cant (P>0.05) effect on the mortality of fish once they were stocked in cages. The results from the present study highlight the ineffi ciency of the addition of these compounds in the water during transportation of pacu.

O objetivo deste estudo foi avaliar a eficiência de uma prática de manejo utilizada e recomendada aos produtores de peixe, trata-se do uso de aditivos na água de transporte de juvenis de pacu (Piaractus mesopotamicus) sobre a sobrevivência pós transporte dos peixes posteriormente estocados em tanques-rede. Foram distribuídos inteiramente ao acaso 800 peixes com aproximadamente 30 ± 1,75 g, em 20 embalagens plásticas de 30 l contendo 40 peixes/embalagem. Os tratamentos foram compostos pelos seguintes aditivos na água de transporte: sal (8 g/l), florfenicol (0,01 g/l), oxitetraciclina (0,001 g/l), associação de sal (8 g/l) + gesso (1 g/l) e um tratamento controle sem adição de aditivos. Após 24h de jejum, os peixes foram despescados e transferidos para embalagens plásticas e transportados durante 2 horas. Mediram-se os parâmetros de qualidade de água como: oxigênio dissolvido, saturação de oxigênio, pH, temperatura, nitrito e amônia no início e ao fi nal do transporte. Verifi couse o uso de aditivos na água de transporte não infl uencia (P>0,05) na diminuição da mortalidade dos animais, ressaltando a inefi ciência do uso destes compostos nesta prática de manejo em pisciculturas.

O objetivo deste trabalho foi avaliar o desempenho zootécnico e as características bromatológicas e hematológicas de pacus alimentados a diferentes frequências de arraçoamento. Três mil e duzentos peixes, com peso inicial médio de 65,9±2,36 g, foram distribuídos em 16 tanques-rede de 5 m³ de volume útil. Durante 65 dias, foram avaliadas quatro frequências de arraçoamento (tratamentos): T1, às 12:00 h; T2, às 8:00 e às 17:00 h; T3, às 8:00, 12:00 e 17:00 h; e T4, às 8:00, 11:00, 14:00 e 17:00 h. Utilizou-se o delineamento experimental inteiramente casualizado, com quatro repetições. Analisaram-se parâmetros de desempenho produtivo, índices de gordura visceral e hepatossomático, composição centesimal da carcaça e parâmetros hematológicos e bioquímicos. Quanto ao ganho de peso, as frequências T3 e T4 proporcionaram melhores resultados do que T1 e T2. Embora a proteína, o colesterol e os eritrócitos tenham apresentado diferenças entre os tratamentos, permaneceram dentro dos valores de referência para pacus cultivados em tanques-rede. A frequência de três arraçoamentos diários resultou em maior ganho de peso, em comparação aos demais tratamentos, sem interferir na saúde e na composição centesimal das carcaças dos animais.

The objective of this work was to evaluate the performance parameters and the chemical composition, and the hematologic characteristics of pacu fed at different feeding frequencies. Three thousand two hundred fish, with 65.9±2.36 g initial weight, were distributed in 16 net cages with 5 m³ total volume. During 65 days, four feeding frequencies (treatments) were evaluated as follows: T1, at 12:00 h; T2, at 8:00 and 17:00 h; T3, at 8:00, 12:00, and 17:00 h; and T4, at 8:00, 11:00, 14:00, and 17:00 h. A completely randomized experimental design was used with four replicates. Performance parameters, visceral-somatic fat and hepatosomatic indexes, carcass proximate composition, and hematological and biochemical parameters were analyzed. For weight gain, T3 and T4 frequencies provided better results than T1 and T2. Although protein, cholesterol and erythrocytes have shown differences between treatments, they remained within the default reference range for pacus reared in net cages. The frequency of three daily feeds, resulted in better weight gain, in comparison to the other treatments, without interfering in animal health and in the proximate composition of animal carcass.

Os diferentes manejos utilizados na piscicultura demandam intenso manuseio, causando estresse aos peixes. O uso de anestésicos é importante para contornar este problema. Este trabalho foi realizado para avaliar o uso de eugenol na indução e recuperação anestésica, em pacus de diferentes classes de peso. Foi desenvolvido um experimento em esquema fatorial 5x5, composto de cinco classes de peso (50 ± 5,61 g; 100 ± 9,36 g; 150 ± 12,29 g; 200 ± 12,73 g; e 250 ± 18,77 g) e cinco concentrações de eugenol (40 mg L-1, 80 mg L-1, 120 mg L-1, 160 mg L-1 e 200 mg L-1). A indução da anestesia foi dividida em quatro estágios, de acordo com o comportamento dos peixes sob efeito do anestésico, registrando-se o tempo de permanência em cada estágio, sendo avaliado o momento de insensibilização e o tempo de recuperação. Para o tempo de indução anestésica, observou-se efeito quadrático, ou seja, quando aumentou-se a dose, houve queda no tempo de indução, com tendência de estabilização em doses crescentes. As melhores respostas de indução anestésica verificadas para o pacu ocorreram nas dosagens de 175 mg L-1, 208 mg L-1, 203 mg L-1, 240 mg L-1 e 225 mg L-1, respectivamente para as classes de peso de 50 g, 100 g, 150 g, 200 g e 250 g. Já para o tempo de recuperação, não foi observada interação entre o menor tempo de indução e menor tempo de recuperação. Sendo assim, as doses que proporcionaram menor tempo de indução para as faixas de peso encontram-se entre 175 mg L-1 e 240 mg L-1.

The different practices used in fish breeding require intense handling, leading to fish stress. The use of anesthetics is important to overcome this problem. This study aimed at evaluating the impact of eugenol on the induction and anesthetic recovery of Piaractus mesopotamicus from different weight classes. An experiment was carried out in a 5x5 factorial scheme, consisting of five weight classes (50 ± 5.61 g, 100 ± 9.36 g, 150 ± 12.29 g, 200 ± 12.73 g and 250 ± 18.77 g) and five eugenol concentrations (40 mg L-1, 80 mg L-1, 120 mg L-1, 160 mg L-1 and 200 mg L-1). The anesthesia induction was divided into four stages, according to the behavior of the anesthetized fish, being the duration of each stage recorded, and the desensitization moment and recovery time evaluated. A quadratic effect was observed at the anesthetic induction time, i.e., when the dose increased, the induction time decreased, tending to stabilize for increasing doses. The best results for anesthetic induction were observed at the 175 mg L-1, 208 mg L-1, 203 mg L-1, 240 mg L-1 and 225 mg L-1 concentrations, respectively for the 50 g, 100 g, 150 g, 200 g and 250 g weight classes. No interaction between the shortest induction time and the shortest recovery time was observed. Thus, the doses which provided a lower induction time for the weight classes range between 175 mg L-1 and 240 mg L-1.

The objective of this study was to evaluate the feeding management of pacu juveniles (P. mesopotamicus) under different feeding rates and its relation with productive performance, body composition and hematological characteristics. A total of 300 fish with initial weight of 84.75±4.52 g were distributed in a completely randomized design composed of four treatments (100, 90, 80 and 70% of feed supply) and five repetitions. The amount of feed was stipulated according to the quantity supplied in the treatment until apparent satiation (100%) of the day before. The decrease in the feeding rate to 70% over satiation apparently improves the apparent feed conversion without harming performance, body composition or biochemical and hematological characteristics of pacu juveniles reared in net cages.

O objetivo neste trabalho foi avaliar o manejo, as características eritrocitárias e o nível de glicose sanguínea de pacus (Piaractus mesopotamicus) estocados em diferentes densidades em tanques-rede. Foram utilizados 2.700 peixes com peso inicial de 142,11 ± 10,54 g, distribuídos em nove tanques-rede de 5 m³ de volume útil durante 240 dias. O delineamento utilizado foi o inteiramente casualizado, com três densidades (200, 300 e 400 peixes por tanque), cada uma com três repetições. Somente o peso final e o ganho de peso diminuíram com o aumento da densidade de estocagem. A biomassa final aumenta de acordo com o número de animais estocados por unidade produtiva. As densidades de criação não influenciaram o rendimento de carcaça, mas afetaram o comprimento total, que foi maior nos peixes criados em baixa densidade, que não diferiram daqueles cultivados em densidade intermediária. Os peixes criados em menor densidade apresentaram maior deposição lipídica, mas não diferiram significativamente daqueles estocados em densidade intermediária. As variáveis eritrocitárias, como eritrócitos totais, hemoglobina, hematócrito, volume corpuscular médio e concentrações de hemoglobina corpuscular média e de hemoglobina corpuscular média, não apresentaram diferenças estatísticas entre as densidades utilizadas e permaneceram na faixa normal para a espécie. Os níveis de glicose no sangue não diferiram significativamente entre as densidades trabalhadas. A densidade de estocagem não influencia os parâmetros eritrocitários, o nível de glicose nem o rendimento de carcaça de pacus. A densidade de 200 peixes/tanque resulta em maior peso final e ganho de peso, porém reduz a produtividade por área e aumenta a deposição lipídica dos peixes.

The aim of this study was to evaluate management, erythrocyte features and blood glucose level of pacu (Piaractus mesopotamicus), stocked at different densities in cages. It was used 2,700 fish with initial average weight of142.11 ± 10.54 g distributed in nine cages of 5 m³ of useful volume during 240 days. A complete random design was used, with three densities (200, 300 and 400 fish per cage), each one with three replicates. Only final weight and weight gain decreased with the increase of stocking density. Final biomass increase according to the number of animals stocked per productive unit. Densities of farming did not influence carcass yield, but they affected total length, which was higher in fish raised in low density, which did not differ from those raised in intermediate density. Fish raised in lower density showed the greatest lipid deposition, but they did not significantly differ from those stocked in intermediate density. Erythrocyte variables like total erythrocytes, hemoglobin, hematocrit, average corpuscular volume, average corpuscular hemoglobin concentrations and average corpuscular hemoglobin did not present statistical differences among the used densities and they remain in the normal range for the species. Levels of glucose in the blood did not differ significantly among the analyzed densities. Stocking densities do not influence erythrocyte parameters, glucose level neither carcass yields of pacu fish. Density 200 fish/cage results in higher final weight and weight gain; however, it reduces productivity per area and increases lipid deposition of the fish.

O presente trabalho foi realizado utilizando a cebola comum (Allium cepa L.) como bioindicador da toxicidade de metais pesados em água de rio. As águas de teste foram coletadas em dois locais: na nascente e na foz do rio Toledo. Os bulbos de A. cepa L. foram cultivados em água de teste com nove níveis de concentração de cobre, zinco e chumbo de 0,1 a 50 ppm. Em laboratório a influência destes líquidos de teste em crescimento de raiz foi examinada durante cinco dias. Em todos os líquidos de teste o metal dissolvido contido foi medido pela técnica TXRF. Para líquidos de teste contendo 0,1-ppm de Cu dissolvido o crescimento da raiz foi reduzido em 50%. Entretanto, ocorreu a mesma redução para 1-ppm de Zn dissolvido. Para Pb dissolvido, o método do Allium teste revela toxidade acima de 0,1 e 0,5 ppm para a nascente e a foz do rio Toledo, respectivamente.

The present work was performed using the common onion (Allium cepa L.) as a bioindicator of toxicity of heavy metals in river water. The test waters were collected at two sampling sites: at the beginning and the end of the Toledo River. The bulbs of A. cepa L. were grown in test water with nine concentration levels of copper, zinc and lead from 0.1 to 50 ppm. In the laboratory, the influence of these test liquids on the root growth was examined during five days. For test liquids containing below 0.03-ppm dissolved Cu the root growth was reduced by 40% However, the same reduction occurred for 1-ppm dissolved Zn. For dissolved Pb, results reveal toxicity above 0.1 and 0.6 ppm at the beginning and the end of the Toledo river water, respectively.