Brazilian Catfish Research Articles

A new species of Creptotrema (Allocreadiidae) in Cambeva davisi (Siluriformes) from river streams in fragments of the Atlantic Rainforest, southern Brazil.

We described Creptotrema cambeve n. sp. from the intestine of the Brazilian catfish Cambeva davisi (Haseman, 1911) (= Trichomycterus davisi) based on integrative analyses using morphological and molecular approaches. Creptotrema cambeve n. sp. closely resembles morphologically Creptotrema paraense Vicente, Santos & Souza, 1978, which was described from a siluriform fish in Northern Brazil; however, the two species differ mainly in the oral and ventral sucker sizes and the distribution of the vitellaria. The phylogenetic analyses of the 28S rDNA placed the sequences of the new species in a monophyletic clade together with all other Creptotrema spp. and as sister taxon of Creptotrema cruste Alcantara, Ebert, Ferreira-Silva, Forti, Morais, Pérez-Ponce de León & Silva, 2024, a parasite from a Brazilian anuran. Genetic divergences between the new species and other Creptotrema spp. varied from 0.2% to 4.3%, further corroborating the distinction of the new taxon. Creptotrema cambeve n. sp. is the 18th nominal Creptotrema species known from South America and the 22nd erected in the genus. This is the first study reporting a trematode in Cambeva spp. hosts and the second parasitological survey carried out for Ca. davisi, a poorly known small endemic fish.

Genome Report of Emergent Fish Pathogen Edwardsiella piscicida Recovered from Pseudoplatystoma corruscans in Brazil.

Edwardsiella piscicida is a Gram-negative bacteria belonging to the Hafniaceae family which affects several species of marine and freshwater fish. We present the complete genome of E. piscicida strain BEP80 recovered from the Brazilian catfish named Surubim (Pseudoplatystoma corruscans), consisting a chromosome of 3,883,256 bp and no plasmids.

Interspecies transmission of Edwardsiella ictaluri in Brazilian catfish (Pseudoplatystoma corruscans) from exotic invasive fish species.

Infections caused by Edwardsiella ictaluri are one of the biggest problems in the catfish industry in North America and have been reported in fishes around the world. E. ictaluri was detected in juvenile pintado Pseudoplatystoma corruscans-a Brazilian catfish-in a farm in Paraná State, Brazil; diseased animals showed ascites and neurological signs of infection, with more than 50% mortality. Exotic invasive species susceptible to this bacterium have been reported in this area. We assessed the susceptibility of pintado to E. ictaluri with experimental infection via intraperitoneal and immersion methods as well as a cohabitation experiment with Nile tilapia Oreochromis niloticus and African walking catfish Clarias gariepinus, 2 exotic invasive species. All pintados challenged by intraperitoneal and immersion routes and those cohabiting with infected C. gariepinus died within 17 d of the challenge. Mortality of Nile tilapia reached 71.42% after the intraperitoneal and 35.71% in the immersion challenges within 28 d, whereas African walking catfish showed zero mortality. Observed clinical signs were comparable to those in the farm and those described in the literature as enteric septicemia of catfish. With this study, we demonstrated the susceptibility of P. corruscans to E. ictaluri, as well as interspecies transmission of this bacterium.

Short communication: Bacillus subtilis C-3102 improves biomass gain, innate defense, and intestinal absorption surface of native Brazilian hybrid Surubim (Pseudoplatystoma corruscans x P. reticulatum)

The aim was to evaluate the effect of a diet supplemented with B. subtilis for a period of 10 days and to verify its effects on the zootechnical performance, hematological parameters, and intestinal histomorphometry of fish. The present study was designed to verify the effects of a commercial product containing Bacillus subtilis C-3102 for short administration period in the diet of Brazilian catfish Pseudoplatystoma sp. The experimental design was completely randomized with five treatments (0, 10, 20, 30, and 40 g of CALSPORIN® kg feed−1) and six replicates. Supplementation with B. subtilis did not influence (p > 0.05) on erythrogram and plasma glucose of fish. However, probiotic supplementation for 10 days was effective and caused beneficial changes in productive performance of the 30 g kg feed−1 group compared to the other groups. In addition, improvements in the immune system, such as an increase in the number of neutrophils, lymphocytes, thrombocytes, and total blood leukocytes were observed in the treated groups, besides increased height and width of the intestinal villi was possibly related with an improvement in nutrient absorption. This study shows the feasibility in to use short time of feeding in the Pseudoplatystoma sp. diet that improved the fish health.

Myxozoan infection in the muscle layer of the intestine of Rhamdia quelen from the Amazon River Basin, Brazil

ABSTRACT: The present study investigated the morphology and pathology associated with the occurrence of cysts caused by Myxobolus sp. in the intestine of the silver catfish Rhamdia quelen . Comparisons with the other Myxobolus species that infect the intestines of cyprinids and siluriforms revealed that the pyriform spores of Myxobolus sp. are similar in shape to those described previously in M. miyairii, M. duodenalis and M. cunhai, but different in size. Morphometric analyses revealed that mature spores of Myxobolus sp. (10.9 x 5.1μm) are smaller than those of most species except M. cunhai (10.0 x 5.0μm), which has been described infecting the Brazilian catfish Pimelodus clarias , although the spores differ morphologically in relation to the shape of the polar capsules. Further research is necessary in order to clarify the taxonomic and phylogenetic relationships among these congeneric species.

Phylogenetic and morphological characterization of trypanosomes from Brazilian armoured catfishes and leeches reveal high species diversity, mixed infections and a new fish trypanosome species.

BackgroundSeveral Trypanosoma species transmitted by leeches infect marine and freshwater fish worldwide. To date, all South American fish trypanosome species identified have been based on unreliable morphological parameters. We recently isolated and cultured trypanosomes from the Brazilian armoured catfishes Hypostomus luetkeni and H. affinis. Here, we report the first phylogenetic analyses of South American (Brazilian) trypanosomes isolated from fish, and from leeches removed from these fish. We also analysed morphologically and morphometrically the different forms of fish, leech and cultured trypanosomes.MethodsV7V8 SSU rRNA and gGAPDH sequences were used for phylogenetic analysis of Brazilian fish and leech trypanosomes. Trypanosomes from cultures, fish blood and leech samples were also characterized morphologically and morphometrically by light and electron microscopy.ResultsIn blood smears from fish high trypanosome prevalence (90–100 %) and parasitemia (0.9-1.0x102) were observed. Phylogenetic relationships using SSU rRNA and gGAPDH showed that, despite relevant sequence divergence, all Brazilian fish (and derived cultures) and leech trypanosomes clustered together into a single clade. The Brazilian clade clustered with European, North American and African fish trypanosomes. Based on sequence analysis, we uncovered a new species of Brazilian fish trypanosome, Trypanosoma abeli n. sp. Trypanosoma abeli cultures contained pleomorphic epimastigotes, small trypomastigotes and rare sphaeromastigotes. Ultrastructural features of T. abeli included a cytostome-cytopharynx complex in epi- and trypomastigotes, a compact rod-like kinetoplast, lysosome-related organelles (LROs) and multivesicular bodies. Trypanosomes found in fish blood smears and leech samples were highly pleomorphic, in agreement with sequence data suggesting that catfishes and leeches often have mixed trypanosome infections.ConclusionsTrypanosoma abeli n. sp. is the first trypanosome from South American fishes isolated in culture, positioned in phylogenetic trees and characterized at the ultrastructural level. Trypanosoma abeli n. sp. is highly prevalent in H. luetkeni and H. affinis armoured catfish from the Atlantic Forest biome, and in other catfish species from the Amazon and the Pantanal. Sequencing data suggested that Brazilian catfish often have mixed trypanosome infections, highlighting the importance of molecular characterization to identify trypanosome species in fishes and leeches.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1193-7) contains supplementary material, which is available to authorized users.

Composition of MSM from Brazilian catfish and technological properties of fish flour

The goal of this study was to analyze the physical and physicochemical composition and microbiological properties of mechanically separated meat (MSM) from Brazilian catfish ( Brachyplatystoma vaillantii ) and to prepare fish flour from this byproduct while assessing its technological properties, physicochemical and microscopic characteristics. After filleting, the residue was transported and stored at −22 °C and then subjected to mechanical meat separation so the fish flour could be prepared. The MSM analysis identified 17 fatty acids, of which the main ones were palmitic, oleic, stearic, palmitoleic, myristic, EPA, and DHA. The catfish MSM's amino acid profile had mainly glutamic and aspartic acids, arginine, lysine, and leucine. Salmonella spp or sulphite-reducing clostridia were not found in the MSM or the fish flour, while counts of coliforms at 45 °C (<3.0 MPN/g) and coagulase-positive staphylococcus (<1 × 101 CFU/g) were within the limits set by the Brazilian legislation. The fish residue had 78.36 g/100 g moisture, 9.52 g/100 g proteins, 10.80 g/100 g lipids and 18.41 mg TVB-N/100 g (within the Brazilian legislation standards). The best condition to prepare the fish flour was defined as 60 °C due to the best fit to the experimental data. The results suggest that using residues from Brazilian catfish filleting to make fish flour resulted in a product with high nutritional value able to increase value of several foodstuffs, besides contributing to the reduction of waste production in the region's fish industries. • EPA and DHA fatty acids were identified in the catfish MSM. • Dispensable, conditionally indispensable and indispensable amino acids found in catfish MSM. • Residues from catfish to make fish flour resulted in a highly nutritious product. • Byproducts has environmental, economic, scientific, and technological importance.

Brazilian catfish parasitized by Epistylis sp. (Ciliophora, Epistylididae), with description of parasite intensity score

The determination of mean intensity of parasitism for colony-forming sessile protozoan such as Epistylis has been a great problem in parasitological studies. Some alternatives have been proposed by researchers for laboratory and field conditions. This study describes the criteria to establish the parasitic intensity score for epistylidid infestation in fish. Parasite distribution and the host-parasite relationship in four species of Brazilian cultured catfish and their hybrids are discussed. The highest prevalence rates were found in the hybrid jundiara, Leiarius marmoratus male × Pseudoplatystoma reticulatum female (96.4%), followed by jurupoca, Hemisorubim platyrhynchos (60%), and the hybrid surubim, Pseudoplatystoma corruscans male × P. reticulatum female (52.7%). Positive correlation between parasitic intensity score and the fish size, weight, and relative condition factor were also observed. These findings indicate that Epistylis infestation in Brazilian catfish is an emerging disease in cultured fish.

Two genetic stocks of Steindachneridion melanodermatum living in sympatry in nature and genetic variability of wild parents and F1 generation

Steindachneridion melanodermatum is a large Brazilian catfish, highly prized for sport fishing and for its meat. Specimens of this species, both caught in nature from Iguacu River and F(1) fish born in captivity, were analyzed with regard to patterns of RAPD molecular markers. Genetic similarity ranged from 0.57 to 0.95; two groups were determined for the wild specimens. The results suggest different genetic lineages in sympatry in nature. Heterozygosity and percentage of polymorphic loci were 0.31 and 79% and 0.23 and 62%, respectively, for the two populations of wild specimens and 0.26 and 66%, respectively, for those born in captivity.

Reproductive status in females of the Brazilian catfish, Pseudoplatystoma fasciatum reared in cages

Summary The distinctive morphological features of the ovaries the ‘cachara’, Pseudoplatystoma fasciatum were characterized macroscopically, and by histology, when reared in cages, from March 2005 to February 2006. Forty eight females (mean total weight = 2.7 kg, mean standard length = 65.1 cm) were allocated to four cages of 2.7 m3 (20 fish/cage) which were installed in four 600 m2 ponds, located at the IP, Pariquera-Acu, Sao Paulo, Brazil. The monthly, samples were fixed in 4%-buffered formalin before preparation for histological examination, ovaries were removed and weighted. The gonadosomatic index (GSI) was calculated as = 100 × weight ovaries/total fish weight. The ovaries are the cystovarian type and macroscopically, were established three stages of ovarian maturation: Resting, developing Maturation (initial, intermediate, final) and Regression (initial, intermediate, final). Based on morphological criteria of those ovaries, the oocyte development has been divided into distinct stages: (i) oocyte growth (vitellogenesis); (ii) oocyte maturation, along which it goes through different phases of development, before (iii) ovulation and, (iv) spawning. When the P. fasciatum were kept in confinement and not induced to breed occurs fail to attain final oocyte maturation, start the process of degeneration. Consequently, the weight started to decline and 45% of the ovaries showed atresia of vitellogenic follicles. This was considered indicative of a recent cessation of the reproductive activity. Such failure could have been caused by stress of the monthly sampling involving a certain degree of disturbance, and perhaps also by the existence of stressors while in captivity. The synchronous ovary contained oocytes in an unique stage of development and had potential to perform total spawning up to one time a year, with the period reproductive beginning in the end of November to the beginning of February, coinciding with the highest water temperatures in the experimental cages (29.0–31.5°C) and the increase of mean values of GSI. During the regression phase, residual oocytes could be observed together with decrease of the mean values of GSI and, the temperatures.

Modulation of ERK1/2 and p38 MAPK by lead in the cerebellum of Brazilian catfish Rhamdia quelen

Lead (Pb 2+) is a neurotoxic trace metal, widespread in aquatic environment that can change physiologic, biochemical and behavioral parameters in diverse fish species. Chemical exposure may drive modulation of mitogen-activated protein kinases (MAPKs) that are a family of highly conserved enzymes which comprise ubiquitous groups of signaling proteins playing critical regulatory roles in cell physiology. Extracellular signal-regulated kinases (ERK1/2) and p38 MAPK control complex programs such as gene expression, embryogenesis, cell differentiation, cell proliferation, cell death and synaptic plasticity. Little information is available about MAPKs in aquatic organisms and their modulation by trace metals. The aim of this work was to determine the modulation of ERK1/2 and p38 MAPK phosphorylation by Pb 2+ in vivo and in vitro, in cerebellar slices of the catfish, Rhamdia quelen. In the in vitro model, slices were incubated for 3 h with lead acetate (1–10 μM). In the in vivo studies, the animals were exposed for 2 days to lead acetate (1 mg L −1). ERK1/2 and p38 MAPK (total and phosphorylated forms) were immunodetected in cerebellar slices by Western blotting. Pb 2+ added in vitro at 5 and 10 μM increased significantly the phosphorylation of both MAPKs. The in vivo exposed animals also showed a significant increase of ERK1/2 and p38 MAPK phosphorylation without changes in the total content of the enzymes. In conclusion, the present work indicates that it is possible to evaluate the ERK1/2 and p38 MAPK activation in the central nervous system (CNS) of a freshwater fish largely distributed in South America. Moreover, Pb 2+, an important environmental pollutant may activate in vitro and in vivo ERK1/2 and p38 MAPK enzymes. These findings are important considering the functional and ecologic implications associated to Pb 2+ exposure of a freshwater fish species, such as R. quelen, and the roles of ERK1/2 and p38 MAPK in the control of brain development, neuroplasticity and cell death.

Induced spawning of hatchery-raised Brazilian catfish, cachara Pseudoplatystoma fasciatum (Linnaeus, 1766)

In the months of January 2001 and 2002, female cachara Pseudoplatystoma fasciatum were selected during their first and second gonadal maturation (2 years and 7 months old and 3 years and 7 months old, respectively) with an of oocyte diameter of 937.5 μm (82.5% with central nuclei and 17.5% with peripheral nuclei). Nine females in first maturation received two doses of carp pituitary extract (CPE), 0.5 mg/kg and 5.0 mg/kg; seven received two doses of human chorionic gonadotropin (hCG), 5 and 10 IU/g; five received doses of 0.5 CPE mg/kg and 5 hCG IU/g (CPE+hCG); and four received 0.9% saline (saline). Nine females from CPE and seven from hCG presented oocytes with the same diameter at the moment of oocyte release (100% with germinal vesicle breakdown and fertilization rate of 53.44±18.3 and 54.81±11.8%; larvae number of 165,330±94.1 and 158,570±20.6, respectively). The five females from CPE+hCG did not respond to the hormonal treatment. The four females from the saline group did not ovulate. In January 2002, 6 of 15 selected females that were going through the second reproductive cycle received CPE (five received hCG and four received saline), showing oocyte diameters similar to the ones in the first maturation. At stripping, CPE females had an oocyte diameter of 1062.5 μm (the hCG females had oocyte diameters ranging from 937.5 to 1125.0 μm; fertilization rates of 56.08±30.9 and 81.90±17.3%; 364,547±244 and 633,129±190, larvae, respectively). The fertilization rates and larvae number were higher in the second gonad maturation, both for CPE and hCG.

HUNGER SUPPRESSES THE ONSET AND THE FREEZING COMPONENT OF THE ANTIPREDATOR RESPONSE TO CONSPECIFIC SKIN EXTRACT IN PINTADO CATFISH

Abstract Although the skin of an injured conspecific releases alarm substance in some fish species, it has been shown that such damage induces feeding behaviour rather than an alarm reaction under conditions of food scarcity. We studied chemical communication associated with this paradox in a Brazilian catfish, the pintado (Pseudoplatystoma coruscans). In preliminary tests pintado were confirmed to demonstrate an alarm reaction to conspecific skin extract. In the experiment we investigated whether skin extract of pintado induces either alarm response (panic or alert component) or feeding in hungry conspecifics. Fish feed-deprived for eight days and fed control fish were exposed to either conspecific skin extract or distilled water (as a control). Alarm reaction was restricted to the skin extract treatment and occurred in the fish irrespective of their hunger state, but the components of this response were significantly affected by hungry. Fed fish showed a complete alarm reaction (dashing and freezing behaviours). Feed-deprived fish exhibited only part of this biphasic response, the dashing component. We conclude that chemicals from injured fish elicit an alarm reaction, which is partially inhibited by feeding motivation.