ABSTRACT. Flaxseed oil is recognized as the plant source richest in α-linolenic acid, whereas clove leaf essential oil has a strong antioxidant capacity. The objective of this study was to determine the in vitro antioxidant capacity of diets containing a combination of flaxseed oil (FO) and clove leaf essential oil (CLEO), as well as to use zebrafish (Danio rerio) to assess their effect on the animals’ growth. Fifty days after hatching, a total of 420 male specimens (0.29 ± 0.04 g) were divided into seven groups for each diet and fed for 55 days to be used, with the diets being: control, absent FO and CLEO; 3% FO + 0.5% CLEO; 3% FO + 1% CLEO; 6% FO + 0.5% CLEO; 6% FO + 1% CLEO; 9% FO + 0.5% CLEO and 9% FO + 1% CLEO. Antioxidant activity was determined through DPPH (2,2-diphenyl-1-picrylhydrazyl) tests, showing interaction effect between factors (FO x CLEO, p < 0.05); the diets containing 1% combined with 3, 6 or 9% of FO presented means higher than those of the 0.5% diets. No mortality was observed during the experiment. For final weight and weight gain, there was no interaction effect (p > 0.05), only isolated effect for FO, with the fish fed 6 and 9% diets having the best results. Final total length and specific growth rates showed interaction effect (p < 0.05). As for specific growth rates, the best response was that of the diet with 6% FO and 0.5% CLEO. Final length showed increase with FO levels, even when there was association with 0.5 or 1% of CLEO. Therefore, combined use of 9% of FL with 0.5% of CLEO is recommended for zebrafish.

ABSTRACT This study aimed at determining the compelling palatability of different protein hydrolysates for Nile tilapia juveniles (Oreochromis niloticus). Four isoproteic (30% crude protein) and isoenergetic (3,200 kcal kg−1) experimental diets were formulated, with a 5% inclusion level of poultry hydrolysate protein (PHF), or swine liver hydrolysate protein (PHS), or feather hydrolysate protein (PHP) and a control treatment containing 5% of fishmeal (FPE). Four juveniles (2.9 ± 0.01 g) were distributed in 10 L tanks and fed four times a day, and before each feeding event, diets were drawn. The same amount of pellets from each diet was offered, and feeding behaviors were recorded during three minutes for each feeding event, referred to the time of capture of the first pellet, number of pellet rejections, and number of approximations without capturing pellets and quantity of consumed pellets. A significant effect (P < 0.05) was observed regarding a higher consumption of pellets and palatability index for PHF, followed by PHS, FPE, and PHP. Therefore, it was concluded that PHF provided the highest compelling palatability for Nile tilapia juveniles, by displaying a 10.82% increase of the palatability index, 17% of final feed consumption, and presented a rejection number 6.89 times lower than FPE.

Resumo: O objetivo deste trabalho foi determinar o coeficiente de digestibilidade aparente (CDA) da proteína bruta, da energia bruta, da gordura e da matéria seca de um hidrolisado proteico de peixe (HPP), feito de resíduos de tilápia-do-nilo (Oreochromis niloticus) e sardinha inteira (Cetengraulis edentulus), e avaliar o desempenho produtivo e o crescimento das fibras musculares de pós-larvas de tilápia-do-nilo. Realizaram-se dois ensaios, o primeiro para a determinação da digestibilidade em 120 alevinos (70,0±2,0 g) e, o segundo, para avaliação do desempenho produtivo de 375 pós-larvas, com três dias de idade, distribuídas em 25 aquários (unidade experimental) com volume útil de 30 L. Cinco rações à base de ingredientes vegetais foram elaboradas, às quais se incluíram os peixes a 0, 2, 4, 6 e 8% de HPP. Para a avaliação do crescimento muscular, oito peixes de cada unidade experimental foram utilizados. Os valores de CDA encontrados foram: 98,29% para matéria seca; 99,28% para proteína bruta; e 99,13% para energia bruta. As melhores respostas zootécnicas quanto ao desempenho produtivo resultaram do tratamento com a inclusão do hidrolisado proteico a 4,75%. As dietas influenciaram a frequência do diâmetro das fibras musculares, principalmente o crescimento por hiperplasia. O HPP pode ser eficientemente utilizado, e sua inclusão a 4,75% é indicada em dietas de tilápia-do-nilo na fase de pós-larva.

Abstract: The objective of this work was to determine the apparent digestibility coefficient (ADC) of crude protein, crude energy, fat, and dry matter of fish protein hydrolysate (FPH), made of by-products of Nile tilapia (Oreochromis niloticus) and whole sardines (Cetengraulis edentulus), and to evaluate the productive performance and muscle fiber growth of Nile tilapia post-larvae. Two trials were conducted, the first one to determine the digestibility in 120 fingerlings (70.0±2.0 g), and the second one to evaluate the productive performance of 375 post-larvae, with three days of age, which were distributed in 25 aquaria with 30 L of useful volume. Five diets were prepared based on vegetable ingredients, to which fish were included at 0, 2, 4, 6, and 8% FPH. For the evaluation of muscle growth, eight fish of each experimental unit were used. The ADC values found were: 98.29% for dry matter; 99.28% for crude protein; and 99.13% for gross energy. The best zootechnical response for the productive performance resulted from the treatment with the inclusion of fish hydrolysate at 4.75%. The diets affected the frequency of the muscle fiber diameters, mainly the growth by hyperplasia. FPH can be efficiently used, and its inclusion at 4.75% is indicated in the diets for Nile tilapia in the post-larvae stage.

Macrobrachium amazonicum é uma espécie nativa vastamente distribuída nas bacias da America do Sul, sendo largamente explorada por pescadores artesanais no Norte e Nordeste do Brasil e com grande potencial para aquicultura. O objetivo deste trabalho foi abordar aspectos gerais da estrutura populacional e biologia reprodutiva (tamanho de primeira maturação, fecundidade e investimento reprodutivo) de M. amazonicum de duas importantes áreas de pesca artesanal de camarão localizada na foz do rio Amazonas, no Estado do Amapá. Os exemplares foram capturados usando 20 armadilhas artesanais, conhecidas localmente como matapi. Um total de 5.179 camarões foi capturado, dos quais 2.975 eram fêmeas e 2.195 eram machos, dando uma razão sexual geral de 1,35: 1 em favor das fêmeas. As proporções sexuais nas áreas de Ilha de Santana e Mazagão mostraram fêmeas predominando na população. Os picos reprodutivos nas duas áreas ocorreram de Janeiro a Abril/2009 e em Dezembro/2010, coincidindo com o período mais chuvoso. Os picos de recrutamento foram observados em junho e julho de 2009. O tamanho das fêmeas ovígeras variou de 11,10 mm a 29,6 mm de comprimento de carapaça. A fecundidade aumentou com o tamanho das fêmeas, chegando até 7.417 ovos, podendo ser considerada baixa comparada a outras espécies estuarinas de Macrobrachium. Volume médio dos ovos aumentou gradualmente durante a embriogênese saindo de 0,112 para 0,220 mm³, representando um aumento global de 68,5% do I ao III estágio embrionário. Os ovos de M. amazonicum podem ser considerados pequenos, típicos de espécies de Macrobrachium que dependem de água salgada para completar seu desenvolvimento larval. Independente do tamanho da fêmea, o investimento reprodutivo de M. amazonicum variou entre 4,8 e 21,85% do seu peso corporal para a produção de ovos.

Macrobrachium amazonicum is an indigenous prawn vastly distributed in basins of South America, widely exploited by artisanal fisheries in northern and northeastern Brazil and, with great potential for aquaculture. This study aimed to investigate general aspects of population structure and reproductive characteristics (size at first maturity, fecundity and reproductive output) of M. amazonicum from two important areas to artisanal prawn fishing located at the mouth of the Amazon River, State of Amapá. The specimens were captured using 20 handcrafted traps called "matapi". A number of 5,179 prawns were captured, 2,975 females and 2,195 males resulting in 1.35:1 female to male ratio. Santana Island and Mazagão Velho showed females predominated in the population. A reproductive peak period was observed from January to April/2009 and in December/2010, coinciding with the period of higher rainfall. The recruitment peak occurred in June and July/2009. Egg-bearing females ranged in size (carapace length) from 11.10 to 29.6 mm. Fecundity increased with female size and reached up to 7,417 eggs. This amount of eggs is considered low if compared with other Macrobrachium estuarine species. Mean egg volume increased gradually from 0.121 to 0.24 mm³ during embryogenesis, representing 68.5% of overall increase from Stage I to Stage III. Eggs of M. amazonicum are small; this is typical for Macrobrachium species, which depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. amazonicum varied between 4.8 and 21.85% of their body weight into eggs production.

Macrobrachium carcinus é uma espécie nativa com reconhecido potencial para ser utilizada na aquicultura, devido seu grande porte e seus bons índices de fecundidade e fertilidade. Apesar de seu evidente potencial para cultivo, poucas informações sobre dieta natural e habito alimentar desta espécie são conhecidos na literatura. O objetivo principal deste estudo foi identificar os itens da dieta natural de M. carcinus, com base na análise de conteúdo estomacal de espécimes coletados no estuário do rio Amazonas entre janeiro de 2009 e janeiro de 2010. A análise do conteúdo estomacal foi feita usando frequência de ocorrência (FO), método de pontos (MP) e índice alimentar (FI). Os dados revelaram que os componentes alimentares mais importantes desta espécie foram detrito, fragmentos animais e vegetais. O item sedimento constituiu o maior componente do estômago com 43,2% pelo MP, 44,9% pelo FI e 100% pela frequência de ocorrência, respectivamente. Diferenças sexuais entre as preferências alimentares sobre os alimentos não foram encontrados no presente estudo. Diferenças sazonais na frequência de itens ingeridos por M. carcinus não foram observados. Os resultados indicaram que M. carcinus pode ser considerado como um onívoro, mas com um componente importante carnívoro, semelhante ao encontrado em outras espécies de Macrobrachium. Outros aspectos sobre o hábito alimentar e morfologia do estômago são brevemente discutidos.

Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrence (FO), methods of points (MP) and feeding index (FI). It was observed that prawns fed on detritus, animals and plant fragments as the most important food items. Sediment accounted for the main stomach content, accounting for 43.2% by the MP, 44.9% by FI and 100% by the FO. Sexual differences in feeding preferences were not found in this study, and seasonal differences in the frequency of items ingested by M. carcinus were not observed. The results indicated that M. carcinus can be considered omnivorous species, but with an important carnivorous component, similar to that found in other Macrobrachium species.

O presente trabalho constitui um estudo inédito sobre a fauna de Brachyura associada à pesca artesanal de camarões na foz do rio Amazonas. Este estudo foi realizado em quatro pontos de coleta distribuídos na foz do Rio Amazonas, entre os meses de janeiro/2009 e janeiro/2010. Os animais foram capturados utilizando armadilhas artesanais denominadas "matapis" usados por pescadores de camarão na região. Em cada ponto da coleta foram usados 20 matapis. Foram identificados seis espécies em um total de 145 indivíduos capturados, sendo todos pertencentes a família Trichodactylidae: Sylviocarcinus maldonadoensis, S. pictus, S. devillei, Valdivia serrata, Dilocarcinus septemdentatus e D. pagei. As espécies mais representativas S. maldonadoensis, S. pictus e S. devillei, foram classificadas como regulares. Quanto à composição da captura temos D. pagei com três exemplares, D. septemdentatus com apenas um exemplar macho S. maldonadoensis com 48 exemplares, S. pictus com 68 exemplares, S. devillei com 22 exemplares e V. serrata com 3 exemplares. A fauna de Brachyura apresentou, em todos os meses, uma biomassa consideravelmente menor se comparada a dos camarões, representando apenas 5% da captura, com uma proporção de 1:0,06. Para maioria das espécies a proporção de machos foi sempre superior a de fêmeas em quase todos os meses de coleta.

The present paper is a pioneering study on the Brachyura bycatch associated with the artisan prawn fisheries at the mouth of the Amazon River. The study was conducted at four collection sites distributed along the mouth of the Amazon River between the months of January/2009 and January/2010. The animals were caught using handcrafted traps called "matapi", which are used by prawn fisherman in the region. Twenty matapis were used at each collection site. A total of 145 specimens were captured and six species were identified, all belonging to the Trichodactylidae family - Sylviocarcinus maldonadoensis, S. pictus, S. devillei, Valdivia serrata, Dilocarcinus septemdentatus and D. pagei. The most representative species, S. maldonadoensis, S. pictus and S. devillei were classified as regular. Regarding the composition of the capture, there were three specimens of D. pagei , only one male specimen of D. septemdentatus, forty-eight specimens of S. maldonadoensis, sixty-eight specimens of S. pictus, twenty-two specimens of S. devillei and three specimens of V. serrata. In all months, the brachyuran fauna showed a considerably lower biomass when compared to the prawns, representing only 5% of the catch, in a ratio of 1:0.06. For most species, the number of males was always higher than the number of females in almost all collection months.