Early ontogeny of the commercially valuable fish red-bellied pacu Piaractus brachypomus (Characiformes, Serrasalmidae) from the Amazon, Brazil.

The initial development of the red-bellied pacu Piaractus brachypomus is described using morphological, meristic and morphometric characteristics. A total of 127 individuals were analysed (47 in the yolk-sac, 35 in pre-flexion, five in flexion, 20 in post-flexion and 20 in juvenile) with standard length varying between 2.92 and 48.61 mm. The larvae are born poorly developed and have a discoidal yolk at ~6.33 mm standard length. During early ontogeny, the mouth passes from terminal to subterminal and the anal opening reaches the vertical line over the midline region of the body. There are changes in body shape from long and moderate to deep, head length from small to large, and eye diameter from moderate to large. Dendritic chromatophores were present in the ventral, dorsal and upper part of the swim bladder in the early larval stages. Rounded spots are evident all over the body in juveniles. The total number of myomeres ranges from 39 to 41 (20-23 pre-anal, 17-20 post-anal). Through the morphometric relationships, it was evidenced that the greatest changes during the initial ontogeny of P. brachypomus occur in the transition from the post-flexion stage to the juvenile period, indicating changes in behaviour, foraging and physiology.

Cloning and tissue distribution of appetite-regulating peptides in pirapitinga (Piaractus brachypomus).

Pirapitinga (or red-bellied pacu, Piaractus brachypomus, Characiforme, Serrasalmidae) is an economically important South American fish for which the endocrine mechanism of the regulation of feeding has never been examined. To better understand these mechanisms, cDNAs encoding the appetite-regulating peptides orexin, cocaine- and amphetamine-regulated transcript (CART), apelin, cholecystokinin (CCK), peptide YY (PYY), leptin and ghrelin were isolated in pirapitinga and their mRNA distributions examined in peripheral tissues and brain. When compared to other fish, the sequences obtained for all peptides were most similar to those of other Characiforme fish (i.e. Mexican cavefish) and Siluriformes (catfish) as well as Cypriniformes (i.e. goldfish, zebrafish). All peptides were widely expressed within the brain. With the exception of CART, which was only expressed in brain, the mRNAs of all peptides were present in several peripheral tissues, including gastrointestinal tract, kidneys and gills. The widespread and peptide-specific distributions suggest that each peptide might have distinct physiological actions in the brain and on peripheral tissues, in particular on the gastrointestinal tract, which include feeding regulation. This preliminary study opens new avenues for further functional studies on the endocrine regulation of feeding in Serrasalmidae fish, including pirapitinga.

Morphology and molecular data of two novel cnidarian myxosporean (Myxobolidae) infecting Piaractus brachypomus from the Amazon basin.

The objective of this study was reports, through morphological and small subunit ribosomal DNA (SSU rDNA) sequencing, two novel myxobolid myxosporeans infecting Piaractus brachypomus, an economicaly important Amazonian fish popularly known as "pirapitinga". Of a total of 25 specimens of P. brachypomus examined 68% had the gill filament parasitized by Henneguya tapariensis n. sp. and 16% had infection of Myxobolus arapiuns n. sp. in the pyloric cecum. The morphological analysis revealed H. tapariensis n. sp. myxospores with an ellipsoid shape and caudal process larger than the length of the body. The polar capsules of same size were elongated and occupied less than half the body. Sequencing of the SSU rDNA generated a partial sequence of 1946 bp. In M. arapiuns n. sp. the myxospores had oval-shaped body and polar capsules of the same size, occupying less than half the body. Sequencing of the SSU rDNA generated a partial sequence of 1950 bp. Phylogenetic analysis revealed a cluster according to the order/family of the host, where H. tapariensis n. sp. was grouped in a subclade with Henneguya brachypomus and Henneguya piaractus and M. arapiuns grouped in a subclade with Myxobolus colossomatis, Myxobolus matosi and Myxobolus pirapitingae.

Genetic Characterization of the Fish Piaractus brachypomus by Microsatellites Derived from Transcriptome Sequencing.

The pirapitinga, Piaractus brachypomus (Characiformes, Serrasalmidae), is a fish from the Amazon basin and is considered to be one of the main native species used in aquaculture production in South America. The objectives of this study were: (1) to perform liver transcriptome sequencing of pirapitinga through NGS and then validate a set of microsatellite markers for this species; and (2) to use polymorphic microsatellites for analysis of genetic variability in farmed stocks. The transcriptome sequencing was carried out through the Roche/454 technology, which resulted in 3,696 non-redundant contigs. Of this total, 2,568 contigs had similarity in the non-redundant (nr) protein database (Genbank) and 2,075 sequences were characterized in the categories of Gene Ontology (GO). After the validation process of 30 microsatellite loci, eight markers showed polymorphism. The analysis of these polymorphic markers in farmed stocks revealed that fish farms from North Brazil had a higher genetic diversity than fish farms from Southeast Brazil. AMOVA demonstrated that the highest proportion of variation was presented within the populations. However, when comparing different groups (1: Wild; 2: North fish farms; 3: Southeast fish farms), a considerable variation between the groups was observed. The FST values showed the occurrence of genetic structure among the broodstocks from different regions of Brazil. The transcriptome sequencing in pirapitinga provided important genetic resources for biological studies in this non-model species, and microsatellite data can be used as the framework for the genetic management of breeding stocks in Brazil, which might provide a basis for a genetic pre-breeding programme.

Parasites in farmed Piaractus brachypomus (Serrasalmidae) in the state of Acre, western Brazilian Amazonia

This study investigated the parasite fauna in Piaractus brachypomus grown in fish farms in the state of Acre, in the western Brazilian Amazon. We examined 160 fish from four farms. Overall parasite prevalence was 66.9%. The fish were parasitized by Anacanthorus spathulatus, Mymarothecium viatorum, Anacanthorus penilabiatus, Clinostomum marginatum, Echinorhynchus jucundus and Henneguya sp., but monogenean species were the dominant parasites. Monogeneans showed an aggregated distribution pattern and there was a weak correlation between host size and abundance of M. viatorum and A. penilabiatus. No difference in the condition factor of parasitized and non-parasitized fish was detected. The fish of all farms had the gills parasitized by A. spathulatus and M. viatorum, but A. penilabiatus was found only in fish from two farms. Echinorhynchus jucundus, C. marginatum and Henneguya sp. were found in only one farm. The differences in parasitism level among the farms are attributable to differences in management and quality of cultivation environments. (AU)

Genetic diversity and population structure of Brycon nattereri (Characiformes: Bryconidae): a Neotropical fish under threat of extinction

Brycon nattereri is an endangered Neotropical fish reported along conserved stretches of the upper Paraná, Tocantins and São Francisco rivers. Populations of this species have been very rare in some Paraná River sub basins. This study analyzes the genetic diversity and population structure of B. nattereri in a restricted area of occurrence recently identified in upper Paraná River basin. Seven microsatellite loci and 497 bp of D-Loop mitochondrial region were examined in 92 individuals from four points along the area of occurrence. Both molecular markers indicated a single population distributed along a stretch of the river approximately 80 km long. Although some of the data suggest an ancient bottleneck, current levels of genetic diversity (H E = 0.574 and h = 0.616) were similar to those of other species of the genus Brycon. The results suggest that the population of B. nattereri has been able to maintain satisfactory levels of genetic diversity, in spite of the small area of occurrence. These data have highlighted an important conservation area and action may prove essential to improve the quality of the environment, and especially the water and riparian plant life, if the area is to be managed and conserved efficiently.(AU)

Brycon nattereri é um peixe Neotropical ameaçado de extinção reportado para trechos conservados dos rios Paraná, Tocantins e São Francisco. Populações desta espécie têm sido muito raras em algumas sub-bacias do rio Paraná. Este estudo analisou a diversidade genética e a estrutura populacional de B. nattereri em uma área de ocorrência restrita recentemente identificada na bacia do alto rio Paraná. Sete locos microssatélites e 497 pb da região mitocondrial D-Loop foram examinados para 92 indivíduos de quatro pontos ao longo da área de ocorrência. Ambos os marcadores moleculares indicaram uma única população distribuída em um trecho de aproximadamente 80 km do rio. Embora alguns dados tenham sugerido um antigo gargalo genético, os atuais níveis de diversidade genética (H E = 0,574, h = 0,616) foram similares aos de outras espécies do gênero Brycon. Estes resultados sugerem que a população de B. nattereri tem mantido níveis satisfatórios de diversidade genética, apesar da pequena área de ocorrência. Estes dados destacaram uma importante área de conservação e ações podem melhorar a qualidade do ambiente, especialmente para a vida aquática e mata ciliar, se a área for eficientemente manejada e conservada.(AU)

Production of cachama reciprocal hybrids in earth ponds / Produção de híbridos recíprocos de tambaqui e pirapitinga em viveiros escavados

ABSTRACT: The growth of cachama hybrids, cachamoto (Colossoma macropomum ♀ x Piaractus brachypomus ♂) and cachamay (P. brachypomus ♀ x C. macropomum ♂) was compared for 154 days to determine which showed the better productivity. The experiment was carried out in three earth ponds, each divided transversely with a plastic net, yielding six experimental units. Juveniles of cachamoto of 12.95±2.43g and 6.75±0.42cm and cachamay of 16.65±3.64g and 7.41±0.62cm were distributed in each sub-tank of 240m2 at a density of 0.5 fish m-2. Fish were fed twice daily except on days when their weight and length, and the physical and chemical parameters of the water were measured. The following productive variables were evaluated: growth in weight and length, daily weight gain, daily feed intake, apparent feed conversion, specific growth rate, condition factor, productivity and the cost/benefit relationship. None of the analyzed variables presented statistical difference between treatments. Physical and chemical parameters of the water remained within the recommended values for cachama, and survival was 100%. Based on the results obtained, it can be concluded that cachama reciprocal hybrids present a similar productive behavior, so that it is indifferent which one is chosen to be raised under the conditions evaluated.

RESUMO: Comparou-se o crescimento de híbridos de tambaqui e pirapitinga, tambatinga (Colossoma macropomum ♀ x Piaractus brachypomus ♂) e pirambaqui (P. brachypomus ♀ x C. macropomum ♂) durante 154 dias para se verificar qual deles apresentava melhor produtividade. O experimento foi realizado em três viveiros de terra, cada um dividido transversalmente com uma rede plástica, originando seis unidades experimentais. Juvenis de tambatinga de 12,95±2,43g e 6,75±0,42cm e pirambaqui de 16,65±3,64g e 7,41±0,62cm foram distribuídos em cada sub-tanque de 240m2 em uma densidade de 0,5 peixe m-2. Os peixes foram alimentados duas vezes por dia, exceto nos dias em que se mediram peso, comprimento e parâmetros físicos e químicos da água. As variáveis produtivas avaliadas foram: crescimento em peso e comprimento, ganho de peso diário, consumo diário de alimento, conversão alimentar aparente, taxa de crescimento específico, fator de condição, produtividade e relação custo/benefício. Nenhuma das variáveis analisadas apresentou diferença estatística entre os tratamentos. Os parâmetros físicos e químicos da água permaneceram dentro dos valores recomendados para tambaqui e pirapitinga e a sobrevivência foi de 100%. Com base nos resultados obtidos, pode-se concluir que os híbridos de tambaqui e pirapitinga apresentam um comportamento produtivo semelhante, de modo que é indiferente qual deles é escolhido para ser criado nas condições avaliadas.

Efectos del biofloc sobre los parámetros de crecimiento de juveniles de cachama blanca Piaractus brachypomus / Biofloc effect on juvenils Cachama blanca Piaractus brachypomus growth parameters / Efeito dos bioflocos sobre os parâmetros de crescimento de juvenis de Pirapitinga Piaractus brachypomus

Resumen El cultivo en biofloc es una alternativa de producción en la cual se utiliza proteína bacteriana de alto valor biológico como posible suplemento alimenticio y como estrategia para ahorrar recursos y mantener la calidad de agua dentro de los parámetros exigidos por la especie. Durante 60 días se comparó el desempeño productivo de juveniles de cachama blanca Piaractus brachypomus cultivados en sistema intensivo con renovación de agua (T1) y con tecnología biofloc (T2). T1 recibió recambios de agua del 50% semanal y limpieza de fondo dos veces por semana; T2 en sistema biofloc (BFT) con adición de melaza en una relación carbono:nitrógeno de 15:1. Ambos tratamientos recibieron alimento balanceado con 24% de proteína de origen vegetal suministrado hasta saciedad aparente cuatro veces/día. Fueron empleados 480 alevinos, con peso promedio de 0,8 ± 0,33 g y talla de 3,0 ± 0,4 cm. Cada 15 días se determinó peso y longitud estándar (LE), ganancia diaria de peso (GDP), tasa específica de crecimiento en peso (TEC), biomasa (B), factor de conversión alimenticia (FCA), sobrevivencia (S) y factor de condición (K). Se midió oxígeno disuelto (OD), temperatura (T°), pH, salinidad (ppT) y sólidos suspendidos totales (SST) dos veces al día. Semanalmente se determinó nitrógeno amoniacal total (NAT), nitrito, nitrato, alcalinidad y dureza. El desempeño productivo no fue diferente entre los tratamientos (P>0,05). Con la tecnología biofloc es posible manejar las mismas densidades de peces y mantener rendimientos productivos adecuados, similares a los de un sistema productivo intensivo aunque optimizando el uso del recurso hídrico.

Abstract Biofloc cultures are an interesting alternative in which bacterial protein with high biological value is used as a possible food supplement and as part of a strategy to keep water quality within the parameters required by a given species. The production performance of juveniles of white cachama Piaractus brachypomus was compared for 60 days. The fish were reared in two systems: one was intensive and had water renewal (T1), while the other had biofloc technology (T2).T1 had 50% of its water changed weekly and the pond's bottom was cleaned twice per week. In contrast, T2 was a biofloc system (BFT) with added molasses in a carbon:nitrogen ratio of 15:1. In both treatments the fish were fed to apparent satiety four times per day. The feed was balanced and had 24% of protein of vegetable origin.A total of 480 fingerlings were used, whose average weight and size were 0.8 ± 0.33 and 3.0 ± 0.4 cm, respectively.The following parameters were determined on a fifteen-day basis: weight, standard length (SL), daily weight gain (DWG), specific rate of growth in terms of weight (SGR), biomass (B), feed conversion ratio (FCR), survival rate (S), condition factor (K). Likewise, dissolved oxygen (DO), temperature (T°), pH and salinity (ppT) were measured twice a day. Furthermore, total suspended solids (TSS) and biofloc volume were measured every two days.The total ammonia nitrogen (TAN) and the levels of nitrite, nitrate, alkalinity and hardness were determined weekly. Production performance showed no variations across treatments (P>0.05).The biofloc technology makes it possible to have the same fish densities as those observed in intensive production systems. Likewise, the production performance values are adequate and similar to those of this kind of system, but the water resource is optimized.

Resumo O cultivo com bioflocos é uma alternativa de produção onde é utilizada proteína bacteriana de alto valor biológico como possível suplemento dietário e como estratégia para poupar recursos e manter a qualidade da agua dentro dos parâmetros exigidos pela espécie. Durante 60 dias o desempenho produtivo dos juvenis de pirapitinga criados em sistema intensivo com renovação da água (T1) e com bioflocos foi comparado (T2) sem renovação, só repor à agua perdida pela evaporação. Os peixes de T1 receberam renovações de água de 50% semanais e, limpeza do fundo duas vezes na semana. Os peixes de T2 estiveram em sistema com bioflocos. Com adição de melaço numa razão carbono: nitrogênio de 15:1. A ração fornecida tinha 24% de proteína vegetal e foi ministrada até saciedade quatro vezes ao dia. Foram utilizados 480 alevinos com peso médio de 0,8 ± 0,33 g e tamanho de 3,0 ± 0,4 cm. Cada 15 dias foi determinado peso e comprimento padrão, ganho de peso diário (GDP), taxa específica de crescimento (TEC), biomassa (B), conversão alimentar, sobrevivência (S) e fator de condição (K). Foi medido oxigênio dissolvido (OD), temperatura, pH, salinidade (ppT) e sólidos suspendidos totais (SST) duas vezes ao dia. Semanalmente foi determinado nitrogênio amoniacal total (NAT), nitrito, nitrato, alcalinidade e dureza. Não foram observadas diferenças no desempenho produtivo entre os tratamentos (P>0,05). Com a aplicação da tecnologia com bioflocos é possível utilizar as mesmas densidades de peixes e manter o desempenho produtivo ótimo, semelhantes aos de um sistema de produção intensiva embora otimizando a utilização da agua.

Dietary protein levels in Piaractus brachypomus submitted to extremely acidic or alkaline pH / Níveis de proteína na dieta de Piaractus brachypomus submetidos a pH extremamente ácidos ou alcalinos

The objective this study was to evaluate the effects of dietary protein levels in pirapitinga, Piaractus brachypomus, submited to extremely acidic or alkaline pH. Juveniles were fed for 20 days with three diets with different crude protein (CP) levels (25.3, 32.4 and 40.0%) and then separated in five groups (n=10, three replicates each) which were kept in 60 L aquaria and exposed to pH 3.0, 3.5, 7.0, 10, or 10.5. Fish were removed from aquaria when they showed loss of swimming balance, and then blood was collected and plasma separated for measurement of Na+, Cl- and K+ levels. The increase of dietary protein levels (up to 40.0% CP) provided some protection for pirapitinga at pH 3.5 or 10.0 because the time to lose equilibrium increased after acute exposure, but was not effective for compensating ion loss at very acidic (Na+ and Cl-) and alkaline (Cl-) pH.

O objetivo deste estudo foi avaliar o efeito dos níveis de proteína na dieta de pirapitinga, Piaractus brachypomus, submetidas a pH extremamente ácido ou alcalino. Os juvenis foram alimentados durante 20 dias com três dietas com diferentes níveis de proteína bruta (PB) (25,3; 32,4 e 40,0%) e, em seguida, foram separados em cinco grupos (n=10, três repetições cada), os quais foram colocados em aquários de 60L e expostos aos pH 3,0; 3,5; 7,0; 10 ou 10,5. Os peixes foram removidos dos aquários quando apresentaram perda de equilíbrio natatório, o sangue foi então coletado e o plasma separado para determinação dos níveis de Na+, Cl- e K+. O aumento dos níveis de proteína na dieta (até 40% PB) forneceu alguma proteção para pirapitingas em pH 3,5 ou 10,0, porque o tempo para perder o equilíbrio natatório aumentou após a exposição aguda, mas não foi efetivo para compensar a perda de íons em pH muito ácido (Na+ e Cl-) ou alcalino (Cl-).

Straminipilous organisms growing on herbivorous pirapitinga (Piaractus brachypomus) and carnivorous piranha (Pygocentrus nattereri) from Poland / Organismos stramenophila em crescimento na herbívora pirapitinga (Piaractus brachypomus) e na carnívora piranha (Pygocentrus nattereri) da Polônia

We investigated the growth of straminipilous organisms on the skin, muscles and liver of herbivorous pirapitinga (Piaractus brachypomus) and carnivorous piranha (Pygocentrus nattereri) in water of three different eutrophication levels. Sixteen straminipilous organism species were found growing on the investigated body parts of both species of fish used as baits. The higher number of species was found on the baits of carnivorous species (15) when compared with the ones from the herbivorous pirapitinga (10 species). The highest number of straminipilous organisms species developed on the skin of both species of fish. The highest number of species of straminipilous organisms was observed growing in the water of the BiaBa river (middle eutrophication), while the lowest number occurred in the baits of vessels with water from the Dojlidy pond (low eutrophication).

Investigamos o crescimento de organismos stramenophila sobre a pele, músculos e fígado da herbívora pirapitinga (Piaractus brachypomus) e da carnívora piranha (Pygocentrus nattereri) em águas de três diferentes níveis de eutrofização. Dezesseis espécies de organismos stramenophila foram encontradas crescendo sobre as partes do corpo investigadas de ambas as espécies de peixes utilizadas como cobaias. O maior número de espécies foi encontrado em cobaias de espécies carnívoras (15), quando comparado com o da herbívora pirapitinga (10 espécies). A maioria das espécies de organismos stramenophila desenvolveu-se sobre a pele de ambas as espécies de peixes. O maior número de espécies de organismos stramenophila foi observado em crescimento nas águas do rio BiaBa (eutrofização do meio), enquanto o número mais baixo ocorreu em cobaias de vasos com água do lago de Dojlidy (eutrofização baixa).

Crescimento e mortalidade de Brycon opalinus (Characiformes, Characidae) no Parque Estadual da Serra do Mar, Mata Atlântica, Estado de São Paulo / Growth and mortality of Brycon opalinus (Characiformes, Characidae) in Serra do Mar State Park, Atlantic Forest, São Paulo State

Os parâmetros de crescimento e mortalidade de machos e fêmeas de Brycon opalinus foram estimados de janeiro a dezembro de 2004 em rios do Parque Estadual da Serra do Mar - Núcleo Santa Virgínia (SP). As distribuições das freqüências nas classes de comprimentos totais foram diferentes para machos e fêmeas. Os parâmetros estimados para os machos e fêmeas foram: L¥(comprimento médio máximo assintótico) = 29,8 e 37,7 cm; k (coeficiente de taxa de crescimento) = 0,54 e 0,56 ano-1; C (amplitude de oscilação sazonal) = 0,3; Wp ("winter point") = 0,7; M (coeficiente de mortalidade natural) = 0,97 e 0,93 ano-1; quatro a cinco coortes e longevidade de 4,58 e 4,53 anos, respectivamente. O crescimento e a mortalidade de B. opalinus estão intimamente relacionados com as características intrínsecas da espécie, assim como com as características ambientais de sazonalidade e de disponibilidade alimentar.

Growth and mortality parameters for males and females of Brycon opalinus were estimated from January through December 2004 in rivers of the Serra do Mar State Park - Santa Virgínia Unit, State of São Paulo. The distributions of the total-length frequency classes were different for males and females. The estimated parameters for males and females were: L¥ (asymptotic maximum length) = 29.8 and 37.7 cm; k (growth coefficient) = 0.54 and 0.56 year-1; C (growth oscillation) = 0.3; Wp (winter point) = 0.7; M (natural mortality coefficient) = 0.97 and 0.93 year-1; four to five cohorts and longevity of 4.58 and 4.53 years, respectively. Growth and mortality of B. opalinus are intimately related to the intrinsic characteristics of the species, as well as to the environmental characteristics of seasonality and availability of food.

Vertebrados consumidos por Brycon opalinus (Pisces, Characidae) em rios do Parque Estadual da Serra do Mar, SP / Vertebrates consumed by Brycon opalinus (Pisces, Characidae) in rivers in State Park of the Serra do Mar (SP, Brazil)

A análise da alimentação da pirapitinga do sul (Brycon opalinus), peixe ameaçado de extinção de rios da Mata Atlântica da Serra do Mar na região Sudeste, revelou a ocorrência de itens alimentares incomuns. As espécies deste gênero são onívoras oportunistas e alimentam-se de itens vegetais e animais, tais como: flores, folhas, frutos e sementes e grande variedade de insetos. Em três rios do Parque Estadual da Serra do Mar - Núcleo Santa Virgínia foram encontrados exemplares de B. opalinus que consumiram três itens animais incomuns, os anfíbios Hypsiboas aff. pardalis (Anura, Hylidae) e Eleutherodactylus guentheri (Anura, Leptodactylidae) e o mamífero Oligoryzomys cf. nigripes (Rodentia, Sigmodontinae). O registro do consumo destas espécies de vertebrados foi relacionado com o período de chuvas, quando o material animal ou vegetal carreado até o rio pode ser consumido por B. opalinus, mesmo que não sejam itens habituais para a espécie. A mata ripária preservada, como foi verificado nos três rios do Parque Estadual da Serra do Mar - Núcleo Santa Virgínia (SP), é de suma importância para o fornecimento de itens alimentares animais e vegetais e pela manutenção das condições bióticas e abióticas para a sobrevivência de B. opalinus.

Analysis of feeding of the pirapitinga do sul, Brycon opalinus, an endangered fish in rivers of the Atlantic Forest of the Serra do Mar in southeastern Brazil, revealed the occurrence of uncommon items. Species of this genus are opportunist omnivores and feed on plant and animal items, such as flowers, leaves, fruits, seeds, and a wide variety of insects. In three rivers of State Park of the Serra do Mar - Santa Virgínia Unit, B. opalinus presented three uncommon animal items: the amphibians Hypsiboas aff. pardalis (Anura, Hylidae) and Eleutherodactylus guentheri (Anura, Leptodactylidae), and the mammal Oligoryzomys cf. nigripes (Rodentia, Sigmodontinae). This register was related with the rains, when animal or plant matter carried into the river can be consumed by B. opalinus, even if they are not habitually eaten by this species. The preserved riparian forest is of prime importance in supplying animal and plant food items and for maintaining biotic and abiotic conditions for the survival of B. opalinus.