Population structure of the migratory fish Prochilodus lineatus (Characiformes) from rio Grande basin (Brazil), an area fragmented by dams

1. Prochilodus lineatus (Prochilodontidae, Characiformes) is a migratory species of great economic importance both in fisheries and aquaculture that is found throughout the Jacui, Paraiba do Sul, Parana, Paraguay and Uruguay river basins in South America. Earlier population studies of P. lineatus in the rio Grande basin (Parana basin) indicated the existence of a single population; however, the range of this species has been fragmented by the construction of several dams. Such dams modified the environmental conditions and could have constrained the reproductive migration of P. lineatus, possibly leading to changes in the population genetic structure. 2. In order to evaluate how genetic diversity is allocated in the rio Grande basin, 141 specimens of P. lineatus from eight collection sites were analysed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with 15 restriction enzymes. 3. Forty-six haplotypes were detected, and 70% of them are restricted. The mean genetic variability indexes (h = 0.7721 and pi = 1.6%) were similar to those found in natural populations with a large effective size. Fst and Exact Test values indicated a lack of structuring among the samples, and the model of isolation by distance was tested and rejected. 4. The haplotype network indicated that this population of P. lineatus has been maintained as a single variable stock with some differences in the genetic composition (haplotypes) between samples. Indications of population expansion were detected, and this finding was supported by neutrality tests and mismatch distribution analyses. 5. The present study focused on regions between dams to serve as a parameter for further evaluations of genetic variability and the putative impact of dams and repopulation programmes in natural populations of P. lineatus. Copyright (C) 2011 John Wiley & Sons, Ltd.

Neoechinorhynchus curemai (Acanthocephala : Neoechinorhynchidae) in Prochilodus lineatus (Osteichthyes : Prochilodontidae)from the Parana River, Brazil

This work evaluated, parasitic infections by Neoechinorhynchus curemai (Acanthocephala: Neoechinorhynchidae) in Prochilodus lineatus captured between August 2000 and August 2001 in the Parana River, Presidente Epitacio, São Paulo, Brazil. of 87 fishes examined, 59 were infected (25 males and 34 females). High mean intensities occurred in August 2000 (45.2, range 2-204), September 2000 (28.5, range 11-73), October 2000 (59.3, range 2-250) and February 2001 (27.3, range 3-73). There was no relationship of rainfall with mean intensity and prevalence. Males were more parasitized (P < 0.05) than females. This work contributes to the knowledge of helminth parasites of fish from a little studied region of the Parana River, showing diversity in their fauna when compared to other places in the same river. (c) 2005 Elsevier B.V. All rights reserved.

Acute lethal and sublethal effects of neem leaf extract on the neotropical freshwater fish Prochilodus lineatus

The aim of this study was to determine the toxicity of the aqueous extract of neem leaves, a product extensively used in fish-farms as alternative for the control of fish parasites and fish fry predators, for the neotropical fish Prochilodus lineatus. The 24 It LC(50) of neem leaf extract for juveniles P lineatus was estimated as 4.8 g L(-1); the fish were then exposed for 24 h to 2.5, 5.0 and 7.5 g L(-1) or only clean water (control). Plasma glucose levels were higher in fish exposed to 2.5 g L(-1) and 5.0 g L(-1) neem extract, relative to control, indicating a typical stress response. Neem extract did not interfere with the osmoregulating capacity of the fish, as their plasma sodium, chloride, total protein and osmolarity did not change. The presence of the biopesticide interfered with the antioxidant defense system of P. lineatus, as there was a decrease in liver catalase activity at all neem concentrations and the detoxifying enzyme glutathione-S-transferase was activated in fish exposed to 5.0 g L(-1). Fish exposed to all neem extract concentrations exhibited damaged gill and kidney tissue. These results indicate that although neem extract is less toxic to P. lineatus than other synthetic insecticides used in fish-farming it does cause functional and morphological changes in this fish species. (c) 2006 Elsevier B.V. All rights reserved.

Histopatologia de fígado, rim e baço de piaractus mesopotamicus, prochilodus lineatus e pseudoplatystoma fasciatum parasitados por myxosporídios, capturados no Rio Aquidauana, Mato Grosso do Sul, Brasil

Este estudo descreveu a histopatologia de rim, baço e fígado de Piaractus mesopotamicus, Prochilodus lineatus e Pseudoplatystoma fasciatum, parasitados por mixosporídios, capturados no Rio Aquidauana, MS. Após necropsia, amostras do fígado, rim cefálico e baço foram colhidas, fixadas em formalina a 10 % tamponada e processadas de acordo com a rotina histológica. Os cortes foram feitos à espessura de 5 μm e corados com hematoxilina-eosina. Foram encontrados Myxobolus porofilus em P. lineatus, M. colossomatis em P. mesopotamicus e Myxobolus spp. nas três espécies de hospedeiros. Cistos de mixosporídios no exame histopatológico foram vistos no fígado e baço de P. mesopotamicus. Mais de 50% das amostras de fígado de P mesopotamicus e P lineatus apresentou hepatodistrofia difusa. Mais de 80 % das amostras de fígado de P. fasciatum apresentou formações hialinas concêntricas e esteatose em 50% das amostras. em 95,23 % das amostras de rins de P. mesopotamicus, foram observadas alterações teciduais, e em mais de 60 % dos casos nefrodistrofia difusa moderada e congestão de sinusóides glomerulares. Alterações teciduais nas amostras de rins de P. lineatus foram observadas em menos de 20 % da amostra. No baço dos peixes ora examinados não foram encontradas lesões dignas de relato.

Transporte de juvenis de curimbatá Prochilodus lineatus em diferentes densidades

Transportation of curimbata Prochilodus lineatus juveniles in different densities. Tins study evaluated the effects of curimbata Prochilodus lineatus transportation in three densities (100, 150 and 250 g L-1) on survival, metabolic, ionic and hematological (red series) variables Curimbata juveniles were transported in plastic bag during six hours, and sampled before packing, immediately after die arrival, 24 and 96 hours after transportation During recovery, higher mortality was seen in fish transported in die highest density Water variables, such as conductivity and total ammonia, presented increased values as density increased (p < 005). whereas the opposite occurred with dissolved oxygen Glucose level observed in the arrival was high, significantly reducing after 96 hours Among ionic variables, chloride decreased in higher fish densities and according to sampling times Red series hematological variables, such as hematocrit, red blood cell and hemoglobin, Increased in arrival, but diminished 96 hours after transportation There were no significant differences in the interaction between density and time of sampling for mentioned variables 250 g L-1 density induced the highest mortality rate and the worst variables values measured 96 hours of recovery after the stressing event was enough to return to initial values for hematological variables, but was not sufficient to return to initial values for metabolic and ionic variables.

Morphometric characteristics of Prochilodus lineatus (Valenciennes 1847), of the migratory and resident stocks of the river Mogí-Guaçu, São Paulo State, Brazil

A espécie Prochilodus lineatus é de grande importância comercial na região dos rios Grande, Pardo e Mogi-Guaçu e tem como característica a formação de grandes cardumes, apta a desenvolver amplos deslocamentos migratórios. O presente trabalho objetivou avaliar, por meio das características morfométricas e etária, se os curimbatás (P. lineatus) dos diferentes estoques migradores e residentes constituem uma única população, havendo interação entre as sub-populações no período de piracema (migração reprodutiva). Utilizou-se um delineamento inteiramente casualizado em esquema fatorial 4 x 2, com quatro tipos de estoques (um residente e três migradores) e dois sexos (macho e fêmea) com trinta repetições, considerando cada peixe como unidade experimental. Foi observada variação de 80,19% para o primeiro componente principal e 8,09% do segundo componente principal fornecida pelas dez variáveis morfométricas dos estoques residentes e migradores. O estoque residente correspondeu aos maiores valores para todas as variáveis morfométricas. Houve sobreposição dos escores individuais das mesmas características entre os estoques migradores. Observou-se predominância de machos entre os estoques residentes e migrador I e II. As semelhanças morfométricas verificadas entre os estoques migradores indicam tratar-se de uma única população, com pequenas variações interpopulacional.

Morfologia e quantificação da microbiota intestinal do curimbatá (Prochilodus lineatus) e do cascudo cinza (Pterygoplichthys anisitsi) cultivados em cativeiro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gonadal steroids levels and vitellogenesis in the formation of oocytes in Prochilodus lineatus (Valenciennes) (Teleostei: Characiformes)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histopathology of gills of Piaractus mesopotamicus (Holmberg, 1887) and Prochilodus lineatus (Valenciennes, 1836) infested by monogenean and myxosporea, caugth in Aquidauana River, State of Mato Grosso do Sul, Brazil

Realizou-se análise histológica de brânquias de 15 espécimes de Piaractus mesopotamicus e 19 Prochilodus lineatus coletados de abril a novembro de 2004, no Rio Aquidauana, MS, com intuito de contribuir com achados anatomopatológicos em brânquias dessas espécies de peixes de água doce. Amostras de brânquias foram fixadas em formalina 10%, tamponadas e processadas conforme rotina histológica. em P. mesopotamicus observou-se presença de monogênea e cistos de mixosporídio da espécie Henneguya piaractus, com localização intralamelar em vários estágios de desenvolvimento, localizados em todas as regiões (basal, mediana ou distal) das lamelas. Cistos intraepiteliais causaram dilatação e deformação das lamelas vizinhas. em brânquias de P. lineatus, observou-se presença de monogênea. Nas duas espécies de hospedeiro foram registradas hiperplasia do epitélio branquial e desorganização estrutural das lamelas em extensas regiões, alterações que causaram a fusão lamelar. em poucos casos registrou-se presença de células inflamatórias mononucleares e focos hemorrágicos na região distal das lamelas.

Hematological parameters in two neotropical freshwater teleost, Leporinus macrocephalus (Anostomidae) and Prochilodus lineatus (Prochilodontidae)

Leporinus macrocephalus is a non-migratory omnivore fish which occurs in waters with a relatively high oxygen rate. Prochilodus lineatus is a migratory fish that inhabits deoxygenated hypolimnion and feeds on detritus material. Red blood cell, thrombocytes and white blood cell counts, hematocrit and hemoglobin, serum electrolytes (sodium, potassium, calcium, magnesium and chloride), metabolic products (total serum protein and plasma glucose) and blood cells major axis length for L. macrocephalus and P. lineatus were compared. White blood cell counts for both species indicated a similar activity of the immune functions. The concentration of total protein, sodium, calcium, magnesium and chloride, MCV, as well as red blood cells, monocytes, and thrombocytes size in L. macrocephalus were higher than in P. lineatus. However, P. lineatus had higher red blood cell counts, hematocrit and hemoglobin, which reflects a considerable adaptation to survive in an environment with low levels of oxygen.

Prevalence and histopathology of Neoechinorhynchus curemai Noronha, 1973 (Acanthocephala: Neoechinorhynchidae) in Prochilodus lineatus Valenciennes, 1836 from Volta Grande Reservoir, MG, Brazil

O presente trabalho estudou a prevalência e a histopatologia de Neoechinorhynchus curemai Noronha, 1973 (Acanthocephala: Neoechinorhynchidae) em curimbatá, Prochilodus lineatus Valenciennes, 1836. Dezoito peixes com comprimento total médio de 46,7 + 1,1 cm e peso médio de 1.674,8 + 75,6 g foram coletados com rede, bimestralmente, de dezembro de 1995 a dezembro de 1996 na usina hidrelétrica do Reservatório de Volta Grande (Cemig), Minas Gerais, Brasil. Dos peixes analisados, 15 estavam infectados com acantocéfalos no intestino (prevalência de 83,3%). A maior intensidade média ocorreu em agosto de 1996, com 66,5 (16 a 208) parasitos. A análise histopatológica revelou completa descamação do epitélio intestinal com severa hiperplasia e hipertrofia das células caliciformes. Observou-se, ainda, forte reação inflamatória na submucosa, deslocamento de feixes, associado a edemas, bem como infiltração mononuclear e eosinofílica.

Recent Studies on Neoechinorhynchus curemai Noronha, 1973 (Acanthocephala: Neoechinorhynchidae), in Prochilodus lineatus Valenciennes, 1836, from Volta Grande Reservoir, MG, Brazil

O presente trabalho estudou a helmintofauna do curimbatá, Prochilodus lineatus Valenciennes, 1836, do reservatório de Volta Grande, MG, Brasil. Foram analisados 18 peixes com comprimento médio de 46,7 ± 1,1 cm e peso médio de 1.674,8 ± 75,6 g, sendo que 15 apresentaram acantocéfalos no intestino com prevalência de 83,3%. O helminto foi identificado como Neoechinorhynchus curemai Noronha, 1973 (Acanthocephala: Neoechinorhynchidae), que diferiu das outras espécies descritas pelas dimensões dos caracteres e pela morfologia. da descrição original de N. curemai difere pelas maiores dimensões dos testículos, pela glândula de cimento alongada, pela presença de núcleos nos lemniscos, pelas dimensões dos ovos e pelos maiores ganchos da probóscide presentes na segunda e na terceira fileiras nos machos e na primeira fileira nas fêmeas. Foi observada menor porcentagem ocupada pelo sistema reprodutivo em relação ao tronco da fêmea. A observação dos parátipos de N. curemai de Noronha (1973) mostrou grande semelhança com os do presente trabalho. Este fato complementa a descrição do helminto em outra localidade.

Structural and ultrastructural characteristics of the yolk syncytial layer in Prochilodus lineatus (Valenciennes, 1836) (Teleostei; Prochilodontidae)

The yolk syncytial layer (YSL) has been regarded as one of the main obstacles for a successful cryopreservation of fish embryos. The purpose of this study was to identify and characterize the YSL in Prochilodus lineatus, a fish species found in southeastern Brazil and considered a very important fishery resource. Embryos were obtained through artificial breeding by hormonal induction. After fertilization, the eggs were incubated in vertical incubators with a controlled temperature (28 degrees C). Embryos were collected in several periods of development up to hatching and then fixed with 2% glutaralclehyde and 4% paraformaldehyde in 0.1 M sodium phosphate buffer (pH 7.3). Morphological analyses were carried out under either light, transmission or scanning electron microscopy. The formation of the YSL in P. lineatus embryos starts at the end of the cleavage stage (morula), mainly at the margin of the blastoderm, and develops along the embryo finally covering the entire yolk mass (late gastrula) and producing a distinct intermediate zone between the yolk and the endodermal cells. The YSL was characterized by the presence of microvilli on the contact region with the yolk endoderm. A cytoplasmic mass, full of mitochondria, vacuoles, ribosomes, endomembrane nets and euchromatic nuclei, indicated a high metabolic activity. This layer is shown as an interface between the yolk and the embryo cells that, besides sustaining and separating the yolk, acts as a structure that makes it available for the embryo. The structural analyses identified no possible barriers to cryoprotectant penetration.

Cytogenetic analysis of A- and B-chromosomes of Prochilodus lineatus (Teleostei, Prochilodontidae) using different restriction enzyme banding and staining methods

Different cytogenetic techniques were used to analyse the chromosomes of Prochilodus lineatus with the main objective of comparing the base composition of A- and B-chromosomes. The results of digestion of chromosomes with 10 different restriction endonucleases (REs), silver staining, CMA(3) staining and C-banding indicated the existence of different classes of highly repetitive DNA in the A-set and also suggested the existence of compositional differences between the chromatin of A- and B-chromosomes. The 5-BrdU incorporation technique showed a late replicating pattern in all B-chromosomes and in some heterochromatic pericentromeric regions of A-chromosomes. The cleavage with RE BamHI produced a band pattern in all chromosomes of P. lineatus which permitted the tentative pairing of homologues in the karyotype of this species. We concluded that the combined use of the above techniques can contribute to the correct identification of chromosomes and the karyotypic analysis in fishes. on the basis of the results, some aspects of chromosome structure and the origin of the B-chromosomes in P. lineatus are discussed.