Abstract A total of 270 fingerlings (10.7 ± 0.06 g of average weight) were randomly distributed in three treatments with three repetitions, according to a completely randomized design, to evaluate the total substitution of a high fishmeal percentage for silages of fishery by-products in extruded diets for Clarias gariepinus. The treatments were catfish fingerling feed with 25% of fish meal (control) and two alternative diets, with 10% (dry basis) of silage: one prepared with 98% of sulfuric acid, and the other with formic acid. Animals were fed for 60 d. No differences were found (P> 0.05) in the final weights (66.63, 66.27 and 70.71 g) and food conversion (1.18, 1.18 and 1.15). However, there were differences for protein efficiency between the diet with fishmeal (2.34) and the silage of fishery products (3.09 and 3.18). Survival was excellent in all treatments (> 96.66%). The economic analysis showed that the profits with silage (US $ 2,534.22 and 2,430.05/t) were superior to control (US $ 1,689.44/t). It is concluded that chemical silages of fishery by-products can replace a high percentage of fishmeal in extruded diets for Clarias gariepinus fingerlings with a positive economic effect, by reducing the importation of fishmeal.

Resumen Un total de 270 alevines (10.7 ± 0.06 g de peso promedio) se distribuyeron al azar en tres tratamientos con tres repeticiones, según diseño completamente aleatorizado, para evaluar la sustitución total de alto porcentaje de harina de pescado por ensilados de subproductos pesqueros en dietas extrusadas para Clarias gariepinus. Los tratamientos fueron el pienso para alevinaje de bagres con 25 % de harina de pescado (control) y dos dietas alternativas, con 10 % (base seca) de ensilado: uno preparado con ácido sulfúrico al 98 %, y el otro con ácido fórmico. Los animales se alimentaron durante 60 d. No se encontraron diferencias (P > 0.05) en los pesos finales (66.63, 66.27 y 70.71 g) y conversión alimentaria (1.18, 1.18 y 1.15). Sin embargo, sí las hubo para la eficiencia proteica entre la dieta con harina de pescado (2.34) y los ensilados de productos pesqueros (3.09 y 3.18). La supervivencia fue excelente en todos los tratamientos (> 96.66 %). El análisis económico mostró que las utilidades con los ensilados (US $ 2 534.22 y 2 430.05 /t) fueron superiores al control (US $ 1 689.44 /t). Se concluye que los ensilados químicos de subproductos pesqueros pueden remplazar un elevado porcentaje de harina de pescado en dietas extrusadas para alevines de Clarias gariepinus con efecto económico positivo, al disminuir la importación de harina de pescado.

RESUMO Para algumas espécies de peixe, a suplementação de taurina na dieta tem-se mostrado necessária em dietas com grande utilização de proteínas vegetais em substituição à farinha de peixe. Na natureza, o pirarucu, Arapaima gigas se alimenta de itens animais ricos em taurina, portanto este estudo avaliou o efeito da suplementação de taurina (0; 0,5; 1; 1,5 e 3%) sobre o crescimento e parâmetros fisiológicos sanguíneos de juvenis da espécie. Uma ração comercial foi utilizada como dieta basal para as dietas experimentais. Trezentos peixes (20,8 ± 2,3 g) foram aleatoriamente distribuídos em 15 tanques e alimentados durante 28 dias. Ao final do ensaio, a suplementação de taurina nas dietas não afetou crescimento, consumo de alimento e eficiência alimentar dos peixes. As quantidades iniciais de taurina (0,18%) e metionina (1,13%) da ração comercial (dieta 0% taurina) foram aparentemente suficientes para promover o crescimento adequado do pirarucu sem alteração dos principais parâmetros fisiológicos do sangue. Futuros estudos que avaliem se a taurina é condicionalmente essencial para pirarucu alimentado com dietas deficientes em metionina são necessários para elucidar a funcionalidade deste nutriente para a espécie.

ABSTRACT For some fish species, dietary taurine supplementation has been proven necessary in feeds with considerable utilization of vegetable proteins to substitute fishmeal. Pirarucu, Arapaima gigas feeds mainly on taurine-rich animal items in nature, therefore this study aimed to evaluate the effect of dietary taurine supplementation (0, 0.5, 1, 1.5 and 3%) on the growth and blood physiological parameters of juvenile pirarucu. A commercial feed was utilized as the basal diet for the experimental diets. Three hundred fish (20.8 ± 2.3 g) were randomly distributed in 15 tanks and fed for 28 days. At the end of the trial, dietary taurine supplementation did not affect fish growth, feed consumption and feed efficiency. The original amounts of taurine (0.18%) and methionine (1.13%) in the commercial feed (0% taurine diet) apparently sufficed to promote adequate pirarucu growth, with no variation noted in the main blood physiological parameters. Further studies to assess whether taurine is conditionally essential for the pirarucu fed methionine-deficient diets are needed to elucidate the functionality of this nutrient for the studied species.

Abstract Objective : To evaluate the addition of sulfuric (98 %) and formic acids on the silage of fishery byproducts and its effect on productive and economic indicators of Clarias gariepinus. Materials and Methods : Two hundred seventy fingerlings, of 10,4 ± 0,06 g of average weight, were used, distributed in a complete randomized design with three treatments and three repetitions. The treatments were: concentrate feed for catfish fattening (control), fish silage prepared with sulfuric acid (98 %) and silage elaborated with formic acid. All the animals were individually weighed for calculating the indicators final average weight, feed conversion, protein efficiency and survival. In addition, the costs of the diets were calculated from the international prices of the raw materials. Simple classification variance analysis was carried out through the statistical package INFOSTAT. Results : No statistical differences were found in final weight (66,3 and 70,7 g), feed conversion (1,18 and 1,15) and protein efficiency (3,09 and 3,18) between the diets with fish silage. These values were higher (p < 0,05) than the ones reached with the control (final weight of 56,4 g; feed conversion of 1,5 and protein efficiency of 2,3). The survival was high in all the treatments (94,4; 100 and 96,7 %). The economic analysis showed that the highest profits were obtained with the silages ($ 2 618,8 and 2 428,5 US/t) compared with the control ($ 2 061,15 US /t). Conclusion : The utilization of silages from fishery byproducts in extruded diets, elaborated with sulfuric (98 %) and formic acids, improved the productive indicators of C. gariepinus, with a positive economic effect by decreasing the import of fish meal.

Resumen Objetivo : Evaluar la adición de los ácidos sulfúrico (98 %) y fórmico en el ensilaje de subproductos pesqueros y su efecto en indicadores productivos y económicos de Clarias gariepinus. Materiales y Métodos : Se utilizaron 270 alevines, de 10,4 ± 0,06 g de peso promedio, distribuidos en un diseño completamente al azar con tres tratamientos y tres repeticiones. Los tratamientos fueron: concentrado para la preceba de bagres (control), ensilado de pescado preparado con ácido sulfúrico (98 %) y ensilado elaborado con ácido fórmico. Se realizó un pesaje individual a todos los animales para el cálculo de los indicadores peso medio final, conversión alimentaria, eficiencia proteica y supervivencia. Además, se calcularon los costos de las dietas a partir de los precios internacionales de las materias primas. Se realizó análisis de varianza de clasificación simple mediante el paquete estadístico INFOSTAT. Resultados : No se encontraron diferencias estadísticas en el peso final (66,3 y 70,7 g), la conversión alimentaria (1,18 y 1,15) y la eficiencia proteica (3,09 y 3,18) entre las dietas con ensilado de pescado. Estos valores fueron superiores (p < 0,05) a los alcanzados con el control (peso final de 56,4 g; conversión alimentaria de 1,5 y eficiencia proteica de 2,3). La supervivencia fue alta en todos los tratamientos (94,4; 100 y 96,7 %). El análisis económico mostró que las mayores utilidades fueron con los ensilados ($ 2 618,8 y 2 428,5 US/t) respecto al control ($ 2 061,15 US /t). Conclusión : La utilización de ensilados de subproductos pesqueros en dietas extrusadas, elaborados con los ácidos sulfúrico (98 %) y fórmico, mejoró los indicadores productivos de C. gariepinus, con un efecto económico positivo al disminuir la importación de harina de pescado.

RESUMO: A qualidade do pescado está condicionada a diversos fatores, entre eles os métodos de insensibilização. Nesta pesquisa foi utilizado o choque elétrico em diferentes intensidades como método de insensibilização do bijupirá (Rachycentron canadum), e avaliados seus efeitos sobre a qualidade dos peixes resfriados. O experimento foi realizado insensibilizando os peixes com eletrochoque de intensidades de 100, 150 e 200 Volts, e armazenados refrigerados durante 21 dias. Os peixes utilizados foram obtidos de uma piscicultura comercial localizada no litoral norte do estado de São Paulo a cerca de 50km, por via marítima, da cidade de Ubatuba-SP. As variáveis de qualidade dos peixes avaliadas foram características físicas, químicas e sensoriais como medidas dielétricas, índice de Rigor Mortir, pH, textura, cor, avaliação sensorial do frescor, ATP e produtos da degradação. O delineamento experimental utilizado foi um fatorial 6X3, seis tempos de análise e três intensidades de choque elétrico. Foram observadas diferenças significativas (P<0,05) para a maioria das variáveis analisadas, tanto para os tratamentos em relação ao tempo, como também para a influência do tempo de armazenamento dentro de cada tratamento. No entanto, o número de variáveis com significância entre os tratamentos foi menor em relação ao número de variáveis em que houve significância para os tempos de conservação, sendo a interação tempoxtratamento a que obteve significância expressiva dentro dos resultados encontrados. Foram observados os melhores resultados para o tratamento com a intensidade em 150 volts para a maioria das variáveis analisadas em que houve diferenças significativas (p<0,05) entre os tratamentos. Concluiu-se também que o bijupirá pode ser conservado em até sete dias após abate em conservação refrigerada utilizando a eletronarcose como método de insensibilização.

ABSTRACT: Fish quality is conditioned by several factors, among them desensitization methods applied for fish managing and slaughtering. This research used electric shock at different intensities as a desensitization method for cobia (Rachycentron canadum) slaughtering and evaluated its effects over fish quality during refrigerated storage. The experiment was carried out by numbing the fish with electroshock at the intensities of 100, 150 and 200 Volts, and keeping them in refrigerated storage for 21 days. On the cobia, obtained from a commercial fish farm the following physical, chemical and sensorial characteristics as quality variables were evaluated: dielectric properties, rigor index, pH, texture, color, sensorial evaluation of freshness, ATP and degradation catabolites. The experimental design was a 6×3 factorial (6 times of analysis and 3 electroshock intensities). Significant differences (P<0.05) were observed for the analyzed variables, as a consequence of desensitization treatments and of storage time within each treatment. However, the number of variables affected by the treatment was smaller than the number of variables significantly affected by the storage time, and the interaction time×treatment was highly significant within the results reported. The best results for the parameters tested were obtained when the treatment at 150 volts intensity with the majority of analyzed variables held significant differences (P<0.05) among treatments. It was also concluded that cobia can be conserved in refrigerated storage within seven days after slaughtering using electro-narcosis as a method of desensitization.

ABSTRACT The objective of this research was to evaluate the growth performance, oxidative stress, and fatty acid profiles of lambari (Astyanax altiparanae) fed diets containing different lipid sources: soybean oil, linseed oil, and freshwater fish residue oil combined or otherwise with sesame oil (SEO). The fish (mean weight 0.95±0.46 g; mean length 4.21±2.77 cm) were distributed into 24 cages (cage capacity: 0.70 m3; fish density: 276 individuals m−3) in six treatments and four replicates. After 80 days of feeding, they were weighed, and samples were collected for assay of catalase, glutathione reductase (GR), and lactate dehydrogenase (LDH) enzyme activities in muscle and analysis of the fatty acid profiles of polar and neutral fractions of whole eviscerated fish. The addition of SEO reduced docosahexaenoic acid (C22:6n-3, DHA) levels but increased the percentage of highly unsaturated n-3 fatty acids and the DHA: eiocosapentaenoic acid ratio, while reduced GR and LDH enzyme activities in muscle. Thus, certain blends of oils added to fish diets can improve the lipid profile of lambari and protect consumers against reactive oxygen species.