No abstract

This study examined the growth performance of Odontesthes bonariensis, O. humensis and hybrid (O. bonariensis X O. humensis) in intensive culture system for a period of 180 days, using the body weight (W), total length (Lt), condition factor (CF), allometric coefficient (b), specific growth rate (SGR) and estimates of body weight and maximum total length (W max , Lt max ) as indicators. Fish were randomly selected from three genetic groups (Bonariensis, Humensis and Hybrid), divided into water recirculation system consisting of 12 tanks (50 L). 12 measurements of body weight and total length (0, 2, 7, 14, 21, 30, 45, 60, 75, 90, 120, 180 days) were taken by means of a random sample of 10 subjects per replicate. All genetic groups grew in weight and length over the period analyzed, being influenced by the genetics of each species. O. bonariensis showed the best performance in growth and hybrid fish showed intermediate growth and estimated maximum body weight exceeding the pure species. Based on these results, it would be helpful the selective breeding and formation of domesticated strains. Key words: Odontesthes bonariensis, Odontesthes humensis, hybrid, Genetic improvement ResumoEste estudo analisou o desempenho em crescimento de Odontesthes bonariensis, O. humensis e do híbrido O. bonariensis e O. humensis em sistema de criação intensivo, por um período de 180 dias, utilizando como indicadores o peso corporal (Pc), comprimento total (Ct), fator de condição (FC), coeficiente alométrico (b), taxa de crescimento específico (TCE) e estimativa de peso corporal e comprimento total máximo (Pc max , Ct max ). Os peixes foram selecionados aleatoriamente de três grupos genéticos (Bonariensis, Humensis e Híbrida), divididos em sistema de recirculação de água composto de 12 aquários de 50L. Foram realizadas 12 medidas de peso corporal e comprimento total (0, 2, 7, 14, 21, 30, 45, 60, 75, 90, 120, 180 dias), por meio de uma amostragem aleatória de 10 indivíduos por repetição. Todos os grupos genéticos cresceram em peso corporal e comprimento total ao longo do período analisado, sendo influenciadas pela genética de cada espécie. O. bonariensis apresentou o melhor desempenho em crescimento e os peixes híbridos apresentaram um crescimento intermediário

A viola é atualmente a espécie de peixe de maior valor econômico da Lagoa Mangueira e, tendo em vista este fato, o objetivo deste trabalho foi analisar seu rendimento corporal e a composição química do filé. Quarenta animais capturados na Lagoa Mangueira foram divididos em dois grupos de 20 animais cada. O peso apresentou uma variação de 128 a 190g no grupo A e de 234 a 293 g no grupo B. A avaliação biométrica foi realizada no Laboratório de Ictiologia da UFPEL, onde os animais foram medidos em comprimento e peso, sendo utilizadas para o cálculo de rendimento corporal. Foram avaliados o rendimento de carcaça, rendimento de cabeça, rendimento visceral, rendimento da pele, rendimento de tronco limpo e rendimento de filé. A análise de composição química foi realizada com filé seco, para se obter os resultados de proteína, extrato etéreo, cinzas e umidade, e na matéria natural para se obter o teor de ácidos graxos. O peso dos animais influencia no rendimento de carcaça. O filé da viola é considerado magro, com alto teor de proteína e maior quantidade de ácidos graxos insaturados em comparação aos saturados. PALAVRAS-CHAVE: Carcaça; composição química; filé-de-peixe; rendimento corporal; viola.

ResumoA excelente qualidade da carne, a alta taxa reprodutiva e o amplo espectro alimentar sugerem grande potencial para cultivo do peixe-rei. Estudos relacionados à nutrição e alimentação são fundamentais para viabilizar o cultivo de espécies nativas e proporcionar o rápido e eficiente consumo do alimento e reduzir o desperdício de nutrientes. O objetivo deste trabalho foi avaliar a melhor frequência de suprimento de alimento para o crescimento do peixe-rei Odontesthes humensis. Para tal, 600 alevinos com peso médio de 13 ± 5,9 mg foram distribuídos aleatoriamente em 12 aquários de 50 L. Foram usados quatro tratamentos: ração uma vez/dia, ração três vezes/dia, ração seis vezes/dia e ração oito vezes/dia. Após 32 dias de experimento, foram avaliados: peso médio final, comprimento total, ganho de peso médio, sobrevivência e taxa de crescimento específico. Durante o período experimental a água manteve-se com temperatura de 23 ± 1,0 °C, oxigênio dissolvido de 6,6 ± 0,8 mg.L -1 , pH de 7,5 ± 0,4, a alcalinidade de 45 ± 5 mg.L -1 e a amônia total de 0,1 ± 0,2 mg.L -1 . As variáveis estudadas apresentaram correlação positiva com a frequência alimentar, porém a alimentação 8 vezes/dia resultou no aumento da heterogeneidade dos animais. Desta forma recomenda-se uma frequência de alimentação de 3 vezes/ dia para alevinos de peixe-rei nesta fase de vida. Palavras-chave: Alimento, dieta, peixe nativo, piscicultura AbstractThe excellent quality of pejerrey, high reproductive rate and broad food spectrum suggest great potential for cultivation. Studies related to nutrition and diet are key to facilitate the cultivation of native species and to provide fast and efficient consumption of food and reduce the waste of nutrients. The aim of this work was evaluate the best frequency of food supply Odontesthes humensis growth. For such, 600 fingerlings with average weight of 13 ± 5.9 mg were equal and randomly distributed in twelve 50 L experiment tanks. After 32 days of the experiment were evaluated: average final weight, total length, weight gain, specific growth rate and survival. During the experimental period the water temperature was 23 ± 1.0 °C, oxygen 6.6 ± 0.8 mg.L -1 , pH at 7.5 ± 0.4, alkalinity at 45 ± 5 mg.L -1 and total ammonia 0.1 ± 0.2 mg.L -1 . The results of this study indicated a positive correlation between feed frequency and harvest weight, however 8 times/day feed regime resulted in a increase of fish size heterogeneity. Therefore it is recommended that a feed frequency of 3 times/day for pejerrey at this stage of life.

Bioplastics are one of the possible alternative solutions to the polymers of petrochemical origins. Bioplastics have several advantages over traditional plastics in terms of low carbon footprint, energy efficiency, biodegradability and versatility. Although they have numerous benefits and are revolutionizing many application fields, they also have several weaknesses, such as brittleness, high-water absorption, low crystallization ability and low thermal degradation temperature. These drawbacks can be a limiting factor that prevents their use in many applications. Nonetheless, reinforcements and plasticizers can be added to bioplastic production as a way to overcome such limitations. Bioplastics materials are not yet studied in depth, but it is with great optimism that their industrial use and market scenarios are increasing; such growth can be a positive driver for more research in this field. National and international investments in the bioplastics industry can also promote the green transition. International projects, such as EcoPlast and Animpol, aim to study and develop new polymeric materials made from alternative sources. One of their biggest problems is their waste management; there is no separation process yet to recycle the nonbiodegradable bioplastics, and they are considered contaminants when mixed with other polymers. Some materials use additives, and their impact on the microplastics they leave after breaking apart is subject to debate. For this reason, it is important to consider their life cycle analysis and assess their environmental viability. These are materials that can possibly be processed in various ways, including conventional processes used for petrochemical ones. Those include injection moulding and extrusion, as well as digital manufacturing. This and the possibility to use these materials in several applications is one of their greatest strengths. All these aspects will be discussed in this review.

Pejerrey (Odontesthes bonariensis) is a native species from Rio Grande do Sul, Uruguay and Argentina where it is of great economic importance for artisanal fishing. One difficulty in laboratory research with pejerrey is related to its sensitivity, as it presents higher basal cortisol levels than other freshwater species. For this reason, the aim of this work was to evaluate the efficiency of benzocaine and clove oil as anesthetics for pejerrey fingerlings. Two experiments were done where fingerlings (57±7.8mm and 1.1±0.44g) were exposed to benzocaine with concentrations between 40mgL -1 and 120mgL -1 and to clove oil with concentrations between 12mgL -1 and 75mgL -1 . Survival, anesthesia induction time and recovery time for each pharmaceutics were evaluated. Both benzocaine and clove oil pharmaceutics showed efficiency as anesthetics for pejerrey fingerlings, with negative correlation between the dose of anesthetics and the anesthesia induction time. For benzocaine, the concentrations between 80mgL -1 and 100mgL -1 showed better results, as for clove oil the optimal concentrations were between 25mgL -1 and 50mgL -1 . On the other hand, the anesthesia recovery time did not present significant variation on the different concentrations of the tested products. The tested products are highly metabolizable by pejerrey.

Communication

No abstract