Use of probiotics in the catfish Sorubim cuspicaudus larviculture

Sorubim cuspicaudus, a migratory catfish distributed in the Magdalena, Sinú, and Catatumbo river basins, is categorized as vulnerable to extinction. Production of fingerlings in controlled environments stands as a strategic conservation approach, and larviculture is a critical phase in rearing this species. Probiotics are used for improvement in the critical stages of fingerling production. The study aimed to evaluate the use of probiotics (Bacillus subtilis and Bacillus licheniformis) during the larviculture phase of S. cuspicaudus. Larvae at 42 hours post-hatching (1.5±0.1mg, total length 5.7±0.4mm) were treated with four levels of probiotic inclusion in the water: 0, 5, 10, and 20ppm for 22 days. Water quality remained within suitable ranges for neotropical catfish species larviculture and the parameters assessed were weight gain (Gw), length gain (Gl), specific growth rate (G), survival rate (S), stress resistance (Sr), intestinal fold length (LF), and colony-forming units (CFU) count. Results showed higher Gl (22.23±3.5mm), Gw (40.0±12.6mg), G (14.9±1.5%/day), LP (205±72.7µm), and CFU (118.7±80.9) were found at 20 ppm (p0.05). The findings of this study suggest that probiotics (Bacillus subtilis and Bacillus licheniformis) could be used as an alternative to advance in the S. cuspicaudus larviculture.

Sorubim cuspicaudus, un bagre migratorio distribuido en las cuencas de los ríos Magdalena, Sinú y Catatumbo, se encuentra catalogado como una especie vulnerable a la extinción. La producción de alevinos en ambientes controlados es considerada como una estrategia crucial para su conservación, y la larvicultura es una fase crítica en la cría de esta especie. Para mejorar esta fase crítica de producción de alevinos se utilizan probióticos. El estudio tenía como objetivo evaluar el uso de probióticos (Bacillus subtilis y Bacillus licheniformis) durante la fase de larvicultura de S. cuspicaudus. Las larvas, a las 42 horas post eclosión (1,5±0,1mg, longitud total 5,7±0,4mm) fueron tratadas con cuatro niveles de inclusión de probióticos en el agua: 0, 5, 10 y 20ppm durante 22 días. La calidad del agua se mantuvo dentro de los rangos adecuados para la larvicultura de especies neotropicales de bagre y los parámetros evaluados fueron el aumento de peso (Gw), el aumento de longitud (GL), la tasa específica de crecimiento (G), la tasa de supervivencia (S), la resistencia al estrés (Sr), la longitud del pliegue intestinal (LF) y el recuento de unidades formadoras de colonias (UFC). Los resultados mostraron mayores GL (22,23±3,5 mm), Gw (40,0±12,6 mg), G (14,9±1,5%/día), LP (205±72,7 µm) y UFC (118,7±80,9) a 20 ppm (p0,05). Los resultados de este estudio sugieren que los probióticos (Bacillus subtilis y Bacillus licheniformis) podrían utilizarse como alternativa para avanzar en la larvicultura de S. cuspicaudus.

Cucullanus pinnai pinnai and C. pinnai pterodorasi (Nematoda Cucullanidae): what does the integrative taxonomy tell us about these species and subspecies classification?

Cucullanus pinnai has been divided in two subspecies (C. pinnai pinnai and C. pinnai pterodorasi) based on the morphology of oesophastome. While C. pinnai pinnai apparently shows low host specificity and broad geographic occurrence, with certain morphological variations, C. pinnai pterodorasi was reported once, parasitizing Pterodoras granulosus. We used an integrative taxonomic approach to evaluate whether or not populations of C. pinnai pinnai from Trychomycterus spegazzinii (Escoipe River, Argentina) and Pimelodus fur (Miranda River, Brazil), and of C. pinnai pterodorasi from Pterodoras granulosus (Miranda River, Brazil) are conspecific. Parasites were observed using light microscopy and genetically characterized based on partial sequences of the 18S and 28S rDNA, ITS1-5.8S-ITS2, and COI mtDNA. Phylogenies were reconstructed and the Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (bPTP), and Automatic Barcode Gap Discovery (ABGD) were used for species delimitation purposes. The present samples formed well-supported monophyletic assemblages, corroborating in part the results of morphological analyses; however, they grouped according to geographic origin. Species delimitation suggested conspecificity of C. pinnai pinnai with C. pinnai pterodorasi from Brazil; consequently, the morphology of oesophastome may be an intraspecific variation. Results also indicated that C. pinnai may represent a species complex as samples from Argentina were suggestive of an independent specific entity. However, definitive affirmations are premature, since there is no autapomorphy for separating C. pinnai from Brazil and Argentina and sampling was limited to three host species from two river basins. The phylogenetic reconstructions also confirmed the artificiality of some genera within Cucullanidae.

Dimethyl acetamide and dimethyl sulfoxide associated at glucose and egg yolk for cryopreservation of Pseudoplatystoma corruscans semen

This study aimed to develop a protocol for the cryopreservation of Pseudoplatystoma corruscans semen. For this, mature males were hormonally induced with a single dose of carp pituitary extract (5 mg/kg body weight). Semen was collected and evaluated. Two cryoprotectants were tested to compose the diluents: dimethyl acetamide (DMA) and dimethyl sulfoxide (Me2SO), in two concentrations (8% and 10%), + 5.0% glucose + 10% egg yolk. The semen was diluted in a 1: 4 ratio (semen: extender), packed in 0.5 mL straws and frozen in a dry shipper container in liquid nitrogen vapors. After thawing, sperm kinetics, sperm morphology and DNA integrity of cryopreserved sperm were evaluated. Pseudoplatystoma corruscans males produced semen with sperm motility > 80%. After thawing, all treatments provided semen with total sperm motility > 40%, with no significant difference (P < 0.05) between them, as well as between the other sperm kinetic parameters evaluated. The treatments with DMA provided a smaller fragmentation of the DNA of the gametes. Sperm malformations were identified in both fresh and cryopreserved semen, with a slight increase in these malformations being identified in sperm from thawed P. corruscans semen samples.(AU)

Este estudo teve como objetivo desenvolver um protocolo para a criopreservação do sêmen de Pseudoplatystoma corruscans. Para tal, machos maduros foram induzidos hormonalmente com uma dose única de extrato de hipófise de carpa (5 mg/kg de peso vivo). O sêmen foi coletado e avaliado. Sendo testados para compor os diluentes, dois crioprotetores: dimetil acetamida (DMA) e dimetil sulfóxido (Me2SO), em duas concentrações (8% e 10%), + 5,0% glicose + 10% gema de ovo. O sêmen foi diluído na proporção 1: 4 (sêmen: extensor), embalado em palhetas de 0,5 mL e congelado em container dryshipper em vapores de nitrogênio líquido. Após o descongelamento, foram avaliados os aspectos cinéticos espermáticos, a morfologia espermática e a integridade do DNA dos espermatozoides criopreservados. Os machos de P. corruscans produziram sêmen com motilidade espermática > 80%. Todos os tratamentos proporcionaram após o descongelamento sêmen com motilidade espermática total > 40%, sem diferença significativa (P < 0,05) entre eles, como também entre os demais parâmetros cinéticos espermáticos avaliados. Os tratamentos com DMA proporcionaram uma menor fragmentação do DNA dos gametas. Malformações espermáticas foram identificadas, tanto no sêmen fresco, como no criopreservado, sendo identificado um aumento discreto dessas malformações nos espermatozoides das amostras de sêmen descongeladas de P. corruscans.(AU)

Species limits and introgression in Pimelodus from the Magdalena-Cauca River basin.

Low morphological differentiation among taxa hampers their appropriate identification, basic biological studies and promotion of any conservation effort. Aiming to provide the first insight into the evolution and speciation among north-western South American members of Pimelodus, this study tested the hypothesis that Pimelodus yuma, Pimelodus grosskopfii and Pimelodus crypticus represent three independently evolving species and explored signals of interspecific hybridisation. The outcomes based on mitochondrial (cox1) and nuclear (RADseq, microsatellites and rag2) markers combined with coalescence-based and allele-frequency methods confirmed that each studied species represents an independently evolving unit. Contrary to expectations, P. yuma was found as a sister clade of P. blochii, while P. crypticus (formerly confused with P. blochii) was phylogenetically closer to P. grosskopfii. We also found strong evidence of ancient introgression (0.66-3.32 mya) between the non-sibling species P. yuma and P. grosskopfii, breaking the absence of interbreeding and the independent evolutionary trajectory among north-western South American Pimelodus during their diversification history, a pre-requisite to define species limits. However, there were non-significant values of current gene flow between them, supporting the hypothesis of full isolation.

Larval diet of two Amazonian goliath catfish species.

Analysis of feeding habits was performed for early life stages of Brachyplatystoma rousseauxii and Brachyplatystoma filamentosum in the Madeira River, Brazil. Stomach contents of B. rousseauxii and B. filamentosum were identified and analysed to provide the percentage of frequency of occurrence (%FO) and area (%A) and the alimentary index (IAi). The order Diptera represented the most important item consumed by both species. This is the first analyses of the trophic ecology of these ecologically and economically important species of the Amazonian region in early life stages.

Testicular structure and development of germ cells of Hypophthalmus marginatus Valenciennes 1840 (Siluriformes: Pimelodidae).

The present study was conducted to assess the testicular structure and germ cell ultrastructure of Hypophthalmus marginatus during spermatogenesis. Semen and sections of the mid-region of the testis were collected, processed, and analyzed using optical and electron microscopy. Macroscopically, the testes of H. marginatus were filiform, and the testicular parenchyma was composed of spermatogenic cells that proliferated, organized within spermatic cysts. During spermiogenesis, spermatids had no nuclear rotation. The proximal centriole was perpendicular to the distal centriole, characteristic of type III spermiogenesis. Spermatozoa were released into the lumen of the seminiferous tubules and had an ovoid head without an acrosome, condensed nucleus, and shallow nuclear fossa. The midpiece was short, with a single long flagellum. The flagellum had the typical axoneme structure, with nine pairs of peripheral and a central pair of microtubules. The thin end piece comprised only peripheral microtubules. Spermatogenesis in H. marginatus features filiform testes, cystic spermatogenesis, and type III spermiogenesis.

Genetic structure and evidence of anthropogenic effects on wild populations of two Neotropical catfishes: baselines for conservation.

Genetic diversity and structure of Pseudoplatystoma corruscans and P. reticulatum, large migratory South America catfishes, where overfishing and the construction of numerous dams in their feeding and reproducing areas are affecting their migratory processes negatively, were studied using microsatellites in samples from Paraguay (that comprises the Pantanal biome), and the upper and lower Paraná Basins. Genetic diversity was in accordance to that observed for other large migratory fishes, but the most geographically isolated populations of P. reticulatum and those P. corruscans subject to anthropogenic effects (stocking and dams) showed lower genetic diversity and evidences of bottlenecks compatible with low effective population size. Pseudoplatystoma reticulatum presented subtle genetic differentiation within the Paraguay area, especially between the edges of its distribution. Pseudoplatystoma corruscans, in this same area, presented a quite homogeneous but significant genetic break between the Paraguay and upper Paraná populations, apparently resulting from natural and historical isolation between the basins until recently. These data demonstrates that, although these Pseudoplatystoma spp. are abundant in the Pantanal area, anthropogenic events are leading to negative effects on their populations, particularly in the upper Paraná Basin. Genetic differentiation observed along each species distribution demands conservation actions to preserve each population's biodiversity. These results represent important genetic information using new microsatellite markers and the first genetic study of P. reticulatum covering this area of its native distribution. Data may also contribute to a better understanding of species migration patterns and to be used as a baseline for proper management.

Supplementary taxonomic description of Demidospermus pinirampi (Monogenoidea, Dactylogyridae), with a new host record and an expansion of its distribution range / Descrição taxonômica complementar de Demidospermus pinirampi (Monogenoidea, Dactylogyridae), com registro de um novo hospedeiro e ampliação de sua área de distribuição

ABSTRACT During a survey conducted in the Lajeado Reservoir of the Tocantins River, in the state of Tocantins, Brazil, dactylogyrids were recovered from the gills of Pimelodina flavipinnis. Initial morphological analysis showed these dactylogyrids shared aspects of character with species of Demidospermus, with affinity to Demidospermus pinirampi, despite exhibiting differences with the original description by Kritsky et al. (1987) regarding the vagina, the base of the male copulatory organ and the shape and length of the bars. The analysis of the holotypes of D. pinirampi and its most morphologically close species, Demidospermus luckyi, revealed that these dactylogyrids were indeed D. pinirampi. This study therefore reports a new host and locality of occurrence, and reviews some measurements of the original description, supplementing and enhancing the morphological diagnosis of D. pinirampi.

RESUMO Durante um levantamento realizado no Reservatório de Lajeado, no Rio Tocantins, no estado de Tocantins, Brasil, dactilogirídeos foram recuperados das brânquias de Pimelodina flavipinnis. A análise morfológica inicial mostrou que esses dactilogirídeos compartilham aspectos de caráter com espécies de Demidospermus, com afinidade com Demidospermus pinirampi, apesar de apresentarem diferenças em relação à descrição original fornecida por Kritsky et al. (1987) com respeito à vagina, à base do órgão copulatório masculino e à forma e comprimento das barras. A análise dos holótipos de D. pinirampi e de sua espécie morfologicamente mais próxima, Demidospermus luckyi, revelou que estes dactilogirídeos eram realmente D. pinirampi. Este estudo, portanto, relata um novo hospedeiro e localidade de ocorrência e revisa algumas medidas da descrição original, complementando a diagnose morfológica de D. pinirampi.

Chromobacterium violaceum (Schröter 1872) isolated from the aquatic environment associated with the fish culture of Jaú, Zungaro jahu (Ihering, 1898) (Siluriformes, Pimelodidae) / Chromobacterium violaceum (Schröter 1872) isolado de ambiente aquático associado à piscicultura de Jaú, Zungaro jahu (Ihering, 1898) (Siluriformes, Pimelodidae) piscicultura

The jau, Zungaro jahu (Ihering, 1898) is an endangered species, rheophilic, reaching 1.5 m and more than 100 kg. During a work of microbiological monitoring of water quality, in the cultivation of Zungaro jahu, microorganisms that were isolated, were previously reported in other studies, as family members Enterobacteriaceae, Staphylococcus and non-fermenting bacilli. However, it was also isolated Chromobacterium violaceum, which despite being a bacterium found in such an environment, it was reported linked to the cultivation of fish. This paper describes the Chromobacterium violaceum founded in a psiculture, which has implications for national fish farming.

O jaú, Zungaro jahu (Ihering, 1898), é uma espécie em extinção, reofílica, atingindo 1,5 m e mais que 100 kg. Durante um trabalho de monitoramento microbiológico da qualidade da água, no cultivo da espécie em foco, foram isolados microrganismos previamente descritos em outros estudos, como membros da família Enterobacteriaceae, Staphylococcus e bacilos não fermentadores. Além desses microrganismos, foi isolada também a espécie Chromobacterium violaceum, que apesar de ser uma bactéria encontrada neste tipo de ambiente, não foi relatada associada ao cultivo de peixes. Este trabalho relata este importante achado, que pode trazer implicações à piscicultura nacional.

Molecular identification of intergenus crosses involving catfish hybrids: risks for aquaculture production

Monitoring of the interspecific hybrid production and trade is essential for the appropriate management of these animals in fish farms. The identification of catfish hybrids by morphological analysis is unreliable, particularly of juveniles and post-F1 individuals. Therefore, in the present study, we used five molecular markers (four nuclear genes and one mitochondrial gene) to detect hybrids in the trade of pimelodid juvenile fish from different stocks purchased of five seed producers in Brazil. Samples commercialized as pintado (pure species Pseudoplatystoma corruscans ) from three fish farms were genetically identified as hybrid cachapinta ( P. reticulatum x P. corruscans ). In the stocks purchased as cachandiá (hybrid between P. reticulatum x Leiarius marmoratus ) and cachapira (hybrid between P. reticulatum x Phractocephalus hemioliopterus ), we suggested the occurrence of intergenus crosses involving the hybrid cachapinta, which was used instead of the pure species P. reticulatum . The problems involving the hybrid cachapinta production were discussed in the present study, especially because these animals have caused genetic contamination and threatened the genetic integrity of natural and cultivated populations. In order to improve the surveillance of the production and provide criteria for the correct management of catfish hybrids, genetic markers has become an excellent alternative to the morphological identification, including juveniles or post-F1 generations.

O monitoramento da produção e comércio de híbridos interespecíficos é essencial para o manejo adequado desses animais em pisciculturas. A identificação de híbridos de bagres por análise morfológica não é confiável, especialmente de juvenis e indivíduos pós-F1. Portanto, no presente estudo, cinco marcadores moleculares (quatro genes nucleares e um gene mitocondrial) foram utilizados para detectar híbridos no comércio de juvenis pimelodídeos de diferentes estoques, comprados de cinco produtores de alevinos no Brasil. As amostras comercializadas como pintado (espécie pura Pseudoplatystoma corruscans ) foram geneticamente identificadas como híbrido cachapinta ( P. reticulatum x P. corruscans ). Nos estoques comprados como cachandiá (híbrido entre P. reticulatum x Leiarius marmoratus ) e cachapira (híbrido entre P. reticulatum x Phractocephalus hemioliopterus ), sugere-se a ocorrência de cruzamentos intergêneros envolvendo o híbrido cachapinta, que foi usado ao invés da espécie pura P. reticulatum . Os problemas envolvendo a produção de cachapinta foram discutidos no presente estudo, especialmente porque estes animais têm causado contaminação genética e ameaçado a integridade genética das populações naturais e cultivadas. Com o intuito de melhorar a fiscalização da produção e fornecer critérios para o manejo correto dos híbridos de bagre, marcadores genéticos têm se tornado uma excelente alternativa para a identificação morfológica, incluindo juvenis ou gerações pós-F1.

Cryopreservation of Trans-Andean shovelnose catfish (Sorubim cuspicaudus) semen using dimethylacetamide / Criopreservación de semen de Bagre blanco (Sorubim cuspicaudus) con dimetilacetamida como crioprotector / Criopreservação de sêmen de Bagre branco (Sorubim cuspicaudus) com dimetilacetamida como crioprotetor

Cryoprotectant solutions of dimethylacetamide (DMA) were used at three inclusion levels (8, 10, and 12%) to evaluate cryopreservation of Trans-Andean shovelnose catfish semen. The solutions also included 6% glucose and 5% skimmed milk powder. Osmolarity of the solutions was measured with an osmometer (Precision System, Osmomette III, USA). Semen was diluted at a 1:4 ratio (semen:solution) and frozen in nitrogen vapors using a dry shipper (MVE 4/2V, USA). Concentration, mobility, speed, and progressivity of cryopreserved and fresh semen (control) were assessed with the SCA® Sperm Class Analyzer (Microptic, Spain) computer-assisted program. Fertility and hatching were evaluated fertilizing one gram of oocytes with cryopreserved and fresh semen, which was then kept in 2L cylinder-conical incubators. The osmolarity of cryoprotective solutions was 1233.3 ± 23.1 mOsm/Kg (8%DMA), 1530 ± 0.0 mOsm/Kg (10% DMA), and 1627.7 ± 5.8 mOsm/Kg (12% DMA). Fresh semen showed better total mobility (99.6 ± 0.4%), percentage of rapid sperm (34.7 ± 12.2%), and progressivity (48.2 ± 12.8%), compared with cryopreserved semen (p<0.05). Cryopreserved semen with 8% DMA had the highest total mobility (55.4 ± 13.6%) (p<0.05) as well as the highest percentage of rapid sperm (1.5-2.5%), total progressivity (1.9 to 10.1%), and curvilinear velocity (29,5-35,9 μm/s) without significant difference with the evaluated DMA percentages (p> 0.05). Fertilization with fresh semen (19.5 ± 4.4%) and 8% DMA cryopreserved semen (17.8 ± 8.3%) were not different (p>0.05). A cryoprotective solution composed of 8% DMA, 6% glucose, and 5% skimmed milk powder is a viable alternative to cryopreserve Trans-Andean shovelnose catfish semen.

Para evaluar la crioconservación de semen de bagre blanco utilizando dimetilacetamida (DMA) fueron preparadas soluciones crioprotectoras con DMA a tres porcentajes de inclusión (8, 10 y 12%), glucosa 6% y leche en polvo descremada 5%. La osmolaridad de las soluciones fue medida con osmómetro (Precision System, Osmomette III, Usa). El semen fue diluido a razón de 1:4 (semen:solución) y congelado con vapores de nitrógeno en dry shipper (MVE 4/2v, Usa). La concentración, movilidad total, velocidad y progresividad del semen crioconservado y fresco (control) fue evaluada con el programa asistido por computador Sperm Class Analyzer SCA® (Microptic, España). La fertilidad y eclosión se evaluaron fertilizando un gramo de ovocitos con semen crioconservado y fresco; mantenidos en incubadoras cilindro-cónicas de 2L. La osmolaridad de las soluciones crioprotectoras fue 1233,3 ± 23,1 mOsm/kg (DMA 8%), 1530 ± 0,0 mOsm/kg (DMA 10%) y 1627,7± 5,8 mOsm/kg (DMA 12%). Semen fresco mostró la mejor movilidad total (99,6±0,4%), porcentaje de espermatozoides rápidos (34,7 ± 12,2%) y progresividad (48,2 ± 12,8%), valores estadísticamente diferentes a los obtenidos con semen crioconservado (p<0,05). La mayor movilidad total se registró con semen crioconservado con DMA 8% (55,4 ± 13,6%) (p<0,05); así como los mayores porcentajes de espermatozoides rápidos (1,5-2,5%), progresividad total (1,9-10,1%) y velocidad curvilínea (29,5-35,9 µm/s) sin presentar diferencia significativa con los diferentes porcentajes de DMA evaluados (p>0,05). La fertilización con semen fresco (19,5 ± 4,4%) y semen crioconservado con DMA 8% (17,8 ± 8,3%) no presentó diferencia significativa (p>0,05). La solución crioprotectora compuesta por DMA 8%, glucosa 6% y leche en polvo descremada 5% es una alternativa viable para la crioconservación de semen de bagre blanco.

Para avaliar a criopreservação de sêmen de bagre branco utilizando dimetilacetamida (DMA) foram preparadas soluções crioprotetoras com DMA a três porcentagens de inclusão (8, 10 e 12%), glucose 6%e leite em pó desnatada 5%. A osmolaridade das soluções foi medida com osmômetro (Precision System, Osmomette III, USA). O sêmen foi diluído em razão de 1:4 (sêmen: diluição) e congelado com vapores de nitrogênio em dry shipper (MVE 4/2v, USA). A concentração, mobilidade total, velocidade e progressividade do sêmen criopreservado e fresco (controle) foi avaliado com o programa assistido por computador Sperm Class Analyzer SCA® (Microptic, Espanha). A fertilidade e eclosão avaliaram-se fertilizando uma grama de ovócitos com sêmen criopreservado e fresco, mantidos em incubadoras cilindro-cônicas de 2L. A osmolaridade das soluções crioprotetoras foi de 1233,3 ± 23,1 mOsm/kg (DMA 8%); 1530 ± 0,0 mOsm/kg (DMA 10%) e 1627,7 ± 5,8 mOsm/kg (DMA 12%). O sêmen fresco mostrou a melhor mobilidade total (99,6 ± 0,4%), a porcentagem de espermatozoides rápidos (34,7 ± 12,2%) e de progressividade (48,2 ± 12,8%), esses valores com sêmen fresco são estatisticamente diferentes aos obtidos com sêmen criopreservado (p<0,05). A maior mobilidade total registrou-se com sêmen criopreservado com DMA 8% (55,4 ± 13,6%) (p<0,05); assim como as maiores porcentagens de espermatozoides rápidos (1,5-2,5%), progressividade total (1,9-10,1%) e velocidade curvilínea (29,5-35,9 µm/s) sem apresentar diferença significativa com as diferentes porcentagens de DMA avaliados (p>0,05). A fertilização com sêmen fresco (19,5 ± 4,4%) e sêmen criopreservado com DMA 8% (17,8 ± 8,3%) não apresentou diferença significativa (p>0,05). A solução crioprotetora composta por DMA 8%, glucose 6% e leite em pó desnatada 5% é uma alternativa viável para a criopreservação de sêmen de bagre branco.

New morphological data on Cucullanus pinnai pinnai (Nematoda) parasitizing Pimelodus maculatus (Pimelodidae) in southeastern Brazil / Novos dados morfológicos de Cucullanus pinnai pinnai (Nematoda) parasito de Pimelodus maculatus (Pimelodidae) do Sudeste do Brasil

This paper describes the morphology of Cucullanus pinnai pinnai parasitizing Pimelodus maculatus in the Guandu River, Brazil, based on differential interference contrast (DIC) microscopy and scanning electron microscopy (SEM), providing new morphological data about this species of parasite. Nematodes were collected between May and October 2012 from specimens of Pimelodus maculatus in the Guandu River (22°48’2”S, 43°37’35”W), in the state of Rio de Janeiro, Brazil. Some characteristics of specimens of Cucullanus in this study fall within the range of morphological variations of previously studied C. pinnai pinnai. Most of the specimens studied here had excretory pore and deirids located at the posterior end of the oesophagus, a feature not recorded in previous studies of this species. In addition, the size of the gubernaculum was larger than the other specimens previously studied. The SEM and DIC analyses of C. pinnai revealed several morphological details of the cephalic region and the tail papillae. With regard to the polymorphism of C. pinnai, morphological and genetic studies of this cucullanid nematode are needed, involving large numbers of host species and a wide geographical distribution.

O presente estudo descreve a morfologia de Cucullanus pinnai pinnai, parasito de Pimelodus maculatus do Rio Guandu, RJ, Brasil, utilizando recursos de contraste diferencial por interferência (DIC) e microscopia eletrônica de varredura (MEV), fornecendo novos dados morfológicos dessa espécie de Cucullanus. Os nematoides foram coletados em Pimelodus maculatus, entre maio e outubro de 2012, no Rio Guandu (22°48'2 "S, 43°37'35" W), Estado do Rio de Janeiro, Brasil. Algumas características dos espécimes de Cucullanus estudados estão de acordo com a amplitude de variação morfológica de C. pinnai pinnai previamente estudados. A posição do poro excretor e deirídeos nos C. pinnai pinnai estudados, é posterior ao final do esôfago na maioria dos espécimes, e essa característica não foi relatada previamente nesta espécie. O tamanho do gubernáculo é maior do que em outros espécimes de C. pinnai pinnai previamente estudados. As análises MEV e DIC demonstraram detalhes morfológicos da região cefálica e as papilas caudais dessa espécie. Em relação ao polimorfismo de C. pinnai pinnai, ao grande número de hospedeiros e à ampla distribuição geográfica desse cucullanídeo, será necessário um estudo que combine características genéticas e morfológicas desse parasito, com o objetivo de verificar possíveis novas espécies, especificidade de hospedeiros e localidades.

New morphological data on Cucullanus pinnai pinnai (Nematoda) parasitizing Pimelodus maculatus (Pimelodidae) in southeastern Brazil / Novos dados morfológicos de Cucullanus pinnai pinnai (Nematoda) parasito de Pimelodus maculatus (Pimelodidae) do Sudeste do Brasil

This paper describes the morphology of Cucullanus pinnai pinnai parasitizing Pimelodus maculatus in the Guandu River, Brazil, based on differential interference contrast (DIC) microscopy and scanning electron microscopy (SEM), providing new morphological data about this species of parasite. Nematodes were collected between May and October 2012 from specimens of Pimelodus maculatus in the Guandu River (22°482S, 43°3735W), in the state of Rio de Janeiro, Brazil. Some characteristics of specimens of Cucullanus in this study fall within the range of morphological variations of previously studied C. pinnai pinnai. Most of the specimens studied here had excretory pore and deirids located at the posterior end of the oesophagus, a feature not recorded in previous studies of this species. In addition, the size of the gubernaculum was larger than the other specimens previously studied. The SEM and DIC analyses of C. pinnai revealed several morphological details of the cephalic region and the tail papillae. With regard to the polymorphism of C. pinnai, morphological and genetic studies of this cucullanid nematode are needed, involving large numbers of host species and a wide geographical distribution.

O presente estudo descreve a morfologia de Cucullanus pinnai pinnai, parasito de Pimelodus maculatus do Rio Guandu, RJ, Brasil, utilizando recursos de contraste diferencial por interferência (DIC) e microscopia eletrônica de varredura (MEV), fornecendo novos dados morfológicos dessa espécie de Cucullanus. Os nematoides foram coletados em Pimelodus maculatus, entre maio e outubro de 2012, no Rio Guandu (22°48'2 "S, 43°37'35" W), Estado do Rio de Janeiro, Brasil. Algumas características dos espécimes de Cucullanus estudados estão de acordo com a amplitude de variação morfológica de C. pinnai pinnai previamente estudados. A posição do poro excretor e deirídeos nos C. pinnai pinnai estudados, é posterior ao final do esôfago na maioria dos espécimes, e essa característica não foi relatada previamente nesta espécie. O tamanho do gubernáculo é maior do que em outros espécimes de C. pinnai pinnai previamente estudados. As análises MEV e DIC demonstraram detalhes morfológicos da região cefálica e as papilas caudais dessa espécie. Em relação ao polimorfismo de C. pinnai pinnai, ao grande número de hospedeiros e à ampla distribuição geográfica desse cucullanídeo, será necessário um estudo que combine características genéticas e morfológicas desse parasito, com o objetivo de verificar possíveis novas espécies, especificidade de hospedeiros e localidades.

Cytogenetics analyses among populations of the fish Iheringichtys labrosus (Kröyer, 1874) (Siluriformes, Pimelodidae). Karyotype analysis, C- banding and AgRONs distribution / Análise citogenética entre populações de peixes Iheringichtys labrosus (Kröyer, 1874) (Siluriformes, Pimelodidae). Análise cariotípica, bandamento C e distribuição das AgRONs

Karyotypic data on Iheringichthys labrosus from several populations of Paraná River/Argentina are presented. The diploid number was 2n=56 and the karyotype consisted of 42m/sm + 14st/a (NF= 98). The AgNORs were observed in telomeres of the long arm of a st/a chromosome pair. These sites were also positive after C-banding. Heterochromatin was observed in the telomeric position in some chromosomal pairs and can be found in one or both metacentric chromosome arms. The obtained results were compared with those reported for different populations from Brazilian rivers and the similarity among them was evident. However, discordant chromosome formulae and karyotype features between samples should be carefully taken because, in some cases, they seem to be more technical artifacts than real differences.

Dados cariotípicos de Iheringichthys labrosus de várias populações do Rio Paraná/Argentina são apresentados. O número diploide foi 2n=56 e o cariótipo constituído de 42m/sm + 14st/a (NF= 98). As AgNORs foram observadas telomericamente no braço longo de um par cromossômico st/a. Estes sítios também apresentaram bandas positivas após bandamento C. Heterocromatina foi observada em posição telomérica em alguns pares cromossômicos e podem ser encontradas em um ou ambos os braços de cromossomos metacêntricos. Os resultados obtidos foram comparados com aqueles reportados em diferentes populações de rios brasileiros e foi evidente uma similaridade entre eles. Entretanto, fórmulas cariotípicas discordantes e características cariotípicas entre exemplares deveriam ser cuidadosamente observadas porque, em alguns casos, eles parecem ser mais artefatos de técnica que diferenças reais.

Cytogenetics of the Porthole Shovelnose Catfish, Hemisorubim platyrhynchos (Valenciennes, 1840) (Siluriformes, Pimelodidae), a widespread species in South American rivers.

Hemisorubim platyrhynchos is a medium- to large-sized pimelodid catfish distributed along several river basins of the Neotropical Region, noteworthy for representing an important fishery source. In this work, Hemisorubim platyrhynchos from three isolated populations were cytogenetically analyzed. The karyotype shows a diploid number of 2n=56 chromosomes comprising 22m, 16sm, 10st, 8a (FN=104). NORs detected by AgNO3 were located in the terminal regions of the short arm of a st chromosome pair, as confirmed by CMA3 and FISH using an 18S rDNA probe. C-banding revealed a small amount of heterochromatin in chromosomes, including the NORs, and one biarmed pair that showed conspicuous positive bands on both arms. This fact was also evidenced when using other banding techniques, such as RE (AluI), and indicates that this pair constitutes a species-specific cytogenetic marker.

Anatomia da cavidade bucofaringeana de Sorubim trigonocephalus (Siluriformes, Osteichthyes) / Anatomy of the buccopharyngea cavity of Sorubim trigonocephalus (Siluriformes, Osteichthyes)

Sorubim trigonocephalus Miranda et Ribeiro, 1920 conhecido popularmente como chinelo, é uma espécie migratória, de importância econômica. Bastante apreciado na gastronomia por apresentar sabor agradável e sem ossos intermusculares (espinhos). Os exemplares foram coletados em um trecho no Rio Teles Pires, localizado no município de Alta Floresta/MT. Anestesiados e sacrificados em solução aquosa de benzocaína, fixados com solução de formoldeído a 10%, transferidos para o Laboratório de Anatomia Animal/Unemat para descrição das características da cavidade bucofaringeana. Esta espécie apresentou uma pré-maxila bem desenvolvida e cabeça achatada dorsoventralmente, boca localizada na porção ventral média da cabeça, com fenda bucal ampla. Os lábios superiores apresentaram pigmentação cinza escuro com pequenas áreas claras, sendo mais largos que os inferiores e não apresentaram pigmentação. Foram identificadas quatro regiões dentígeras na porção anterior da cavidade bucal e duas na região da faringe, todas com dentes viliformes. A porção posterior da cavidade bucal era limitada lateralmente por quatro pares de arcos branquiais que decresciam em tamanho do primeiro ao último par, crânio-caudal, formados por dois ramos: o superior, mais curto, e o inferior, mais longo. A cavidade bucofaringeana de S. trigonocephalus se mostrou semelhante à de outros teleósteos descritos na literatura, estando adaptado ao hábito alimentar com dieta carnívoro-ictiofágica e diferindo apenas pela ausência de língua estrutural com pré maxila bem desenvolvida apresentando dentes viliformes.

Sorubim trigonocephalus Miranda et Ribeiro, 1920 is popularly known as slipper, migratory specie of economic importance. It is much appreciated in gastronomy because it has good flavor and no intermuscular bones (spines). Specimens were collected on a stretch of the Teles Pires river, located in Alta Floresta/MT, anesthetized and euthanized in aqueous solution of benzocaine, fixed with 10% formaldehyde and transferred to the Laboratory of Animal Anatomy of Unemat to be analyzed and described the characteristics of the buccopharyngeal cavity. With a premaxilla well developed and head dorsoventrally flattened, S. trigonocephalus show out located on the ventral portion of the head mouth wide slit. The upper lip pigmentation had dark gray with small light areas, wider than the and without pigmentation. Was identified four dentigerous regions in in the anterior oral cavity and two in the pharynx region, both with viniliform tooth. The posterior portion of the oral cavity was bounded laterally by four pairs of gill arches that decreased in size from first to last pair, formed by two branches: the higher, shorter, and the lower, longer. The buccopharyngea cavity of S. trigonocephalus showed similar to other teleosts described in the literature, and is adapted to eating habits with diet ictiophagic carnivore and differing only by the absence of a structural tongue and pre maxilla well developed showing viniliform tooth.

Breeding, growth and exploitation of brachyplatystoma rousseauxii castelnau, 1855 in the caqueta river, Colombia

The main life history traits of the large Amazonian migratory catfish Brachyplatystoma rousseauxii were determined in the Caqueta River, Colombia. The breeding season occurred during the rising and falling water periods. The size at first sexual maturity was significantly larger for females (88.5 cm Ls) than males (81.7 cm). Both males and females reproduce for the first time between their third and fourth year. The growth characteristics were estimated using length frequency analyses. Females grew systematically larger than males, the difference being about 9% after the first year and increasing to 12% for ten years old individuals. Mortality estimates, calculated from different models, some taking into account the effect of body size, ranged from 0.32 to 0.42 year-1 for natural mortality and from 0.72 to 0.82 year-1 for fishing mortality, indicating high fishing pressure in the Caqueta River, higher than in the Peruvian Amazon. Resulting exploitation rates (0.63 to 0.72) pointed towards overexploitation of the species in the Caqueta. The situation calls for a concerted management between the countries sharing this resource (Brazil, Colombia, and Peru) and potential solutions are proposed.

Se determinaron las principales características del ciclo biológico de dorado Brachyplatystoma rousseauxii en el río Caquetá, Colombia. La época reproductiva ocurre durante la transición del período de aguas altas a aguas en descenso. La talla de primera madurez sexual fue significativamente mayor en hembras (88,5 cm Ls) que en machos (81,7 cm). Tanto hembras como machos se reproducen por primera vez entre su tercer y cuarto año de vida. Los parámetros de crecimiento fueron estimados mediante el análisis de frecuencia de tallas. Las hembras alcanzan un mayor tamaño que los machos, con una diferencia de cerca del 9% en el primer año que luego aumenta hasta un 12% en el décimo año de edad. La estimación de mortalidad, calculada a partir de diferentes modelos, variaron entre 0,32 a 0,42 años-1 para la mortalidad natural y 0,72 a 0,82 años-1 para la mortalidad por pesca, lo que indica una alta presión de la pesca en el río Caquetá, mucho más elevada que en la Amazonía peruana. Las tasas de explotación resultantes (0,63 a 0,72) para el río Caquetá, señalan una sobre-utilización del recurso. La situación exige una gestión concertada entre los países que comparten y utilizan con elevada frecuencia este recurso amazónico (Brasil, Colombia y Perú), por lo que se proponen posibles estrategias de solución.

Diet of Lontra longicaudis (Carnivora: Mustelidae) in a pool system in Atlantic Forest of Minas Gerais State, southeastern Brazil / Dieta de Lontra longicaudis (Carnivora: Mustelidae) em um sistema de poções na Floresta Atlântica do Estado de Minas Gerais, sudeste do Brasil

The present study aimed to investigate the feeding habits of Lontra longicaudis in a pool system within the Private Reserve of Natural Patrimony (RPPN) Usina Maurício, located in Paraíba do Sul river basin, Atlantic Forest of southeastern Minas Gerais State. The diet composition was determined based on the identification of items present in 212 scats sampled between July 2008 and October 2009 in a 4.1 km stretch of the pool system. The found items and its respective percentages of occurrence were: mollusks (0.5%), insects (16.5%), spiders (1.4%), crustaceans (3.3%), fish (96.7%), amphibians (0.9%), snakes (3.8%), birds (2.8%), mammals (8.5%) and fruits (0.5%). Among fish, the identified families and respective percentages of occurrence were: Loricariidae (65.4%), Pimelodidae (42.9%) Cichlidae (22%), Characidae (7.3%), Erythrinidae (3.9%), Synbranchidae (2.4%), Anostomidae (2%) . Therefore fish make up the most consumed item in the study area, with the predominance of benthic siluriformes (families Loricariidae and Pimelodidae).

O presente estudo teve como objetivo investigar os hábitos alimentares de Lontra longicaudis em um sistema de poções na Reserva Particular do Patrimônio Natural ­ RPPN Usina Maurício, localizada na bacia do rio Paraíba do Sul, Mata Atlântica do Sudeste do Estado de Minas Gerais. A composição da dieta foi determinada com base na identificação de itens presentes em 212 amostras de fezes coletadas entre julho de 2008 e outubro de 2009 em um trecho de 4,1 km de um sistema de poções. Os itens alimentares encontrados e suas respectivas porcentagens de ocorrência foram: moluscos (0,5%), insetos (16,5%), aranhas (1,4%), crustáceos (3,3%), peixes (96,7%), anfíbios (0,9%), serpentes (3,8%), aves (2,8%), mamíferos (8,5%), frutos (0,5%). Dentre os peixes, famílias identificadas e suas respectivas porcentagens de ocorrência foram: Loricariidae (65,4%), Pimelodidae (42,9%) Cichlidae (22%), Characidae (7,3%), Erythrinidae (3,9%), Synbranchidae (2,4%), Anostomidae (2%). Os peixes, portanto, representaram o item mais consumido na área de estudo, com predominância de siluriformes bentônicos (famílias Loricariidae e Pimelodidae).

Variação espacial e sazonal de microrganismos associados ao cultivo do Zungaro jahu (Ihering, 1898), na Estação Ambiental de Volta Grande no Estado de Minas Gerais / Spatial and seazonal variations of microorganisms associated with cultivation Zungaro jahu (Ihering,1898), at Estação Ambiental de Volta Grande in the State of Minas Gerais

Objetivo - Identificar a variação espacial e a sazonal de microrganismos associados ao cultivo semi-intensivo do Zungaro jahu. Métodos - As amostras de água foram coletadas ao longo de um eixo longitudinal em uma piscicultura, no município de Conceição das Alagoas/MG e semeadas em diferentes meios de cultura. Os microrganismos foram isolados e identificados. Resultados - Foram identificados10 gêneros de bactérias. Para os cinco pontos de coleta analisados, obteve-se uma diversidade de 11 espécies de bactérias Gram-negativas e 3 espécies de bactérias Gram-positivas. Conclusão - A análise de variação sazonal apontou para uma redução das categorias taxonômicas em julho, o que pode estar relacionado às baixas temperaturas observadas neste período. A análise da variação espacial mostrou que o tanque que recebe a água de toda a piscicultura apresenta maior diversidade microbiana provavelmente decorrente da adição de matéria orgânica utilizada como insumo.

Objective - To identify the spatial and seasonal variation of microorganisms associated with Zungaro jahu cultivation semi-intensive. Methods - Water samples were collected along a longitudinal axis in a fish farming Conceição das Alagoas county, Minas Gerais-Brazil, and seeded in different culture medium. Results - Ten bacteria genus were isolated and identified 11 of microorganisms and 3 species of Gram-negative and Gram-positive bacteria, respectively was obtained in the five collected points analyzed. The seasonal variation analysis indicated a reduction of taxonomic categories in July, must be directly associated with the low temperatures. Conclusion - The analysis showed that space variation of the tank which receives water from the whole farm-fish has a higher microbial diversity; probably due to the addition of organic matter used in fish feed.

Chromosomal analyses in Megalonema platanum (Siluriformes: Pimelodidae), an endangered species from South American rivers

Este estudo apresenta dados cromossômicos de Megalonema platanum do rio Tibagi, Paraná, Brasil e do rio Paraná, Argentina. O número diploide foi igual 54 com composição cariotípica de 24m+16sm+2st+12a em ambas populações. Os sítios AgNORs foram detectados na posição terminal de um par submetacêntrico das duas populações analisadas, coincidindo com constrição secundária no braço curto do par 15. CMA3 e FISH com sonda de DNAr 18S exibiram sinais fluorescentes que correspondem aos sítios AgNORs e à constrição secundária. A presença de um pequeno cromossomo supranumerário acrocêntrico foi observado em M. platanum do rio Tibagi, com heterocromatina centromérica. Outros blocos heterocromáticos foram evidenciados na posição terminal de alguns cromossomos e um par cromossômico submetacêntrico grande, provavelmente o primeiro par, mostrou heterocromatina intersticial. Na população do rio Paraná foram observados ainda blocos heterocromáticos em ambas regiões terminais em alguns cromossomos. Este trabalho mostra pela primeira vez dados citogenéticos de M. platanum, que é uma espécie muito rara na bacia do rio Paraná e pode estar ameaçada de extinção.

This study presents chromosomal data of Megalonema platanum from rio Tibagi, Paraná, Brazil and from rio Paraná, Argentina. The diploid number was equal 54 with karyotype composition of 24m+16sm+2st+12a in both populations. The AgNOR siteswere detected in the terminal position of a submetacentric pair of the two analyzed populations, coinciding with secondary constrictions on the short arm of pair 15. CMA3 and FISH with 18S rDNA probe displayed fluorescent signals that correspond to the AgNOR sites and secondary constriction. The presence of a small acrocentric supernumerary chromosome can be observed in M. platanum from rio Tibagi, with centromeric heterochromatin. Others heterochromatic blocks were evidenced in the terminal position of some chromosome and one metacentric large chromosome pair, probably the first pair, showed an interstitial heterochromatin. In the population of the rio Paraná were still observed heterochromatic blocks in both ends in some chromosomes. This work brings for the first time cytogenetic date of M. platanum, which is a very rare species in the rio Paraná basin and may be endangered.