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1.
Environ Monit Assess ; 191(11): 700, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31667668

RESUMO

The distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the muscle, liver, spleen and kidney tissue of two fish species was studied using an optimised diatomaceous earth assisted modified QuEChERS extraction method. Five-year-old free-ranging male African sharptooth catfish (Clarias gariepinus) and 5-year-old male common carp (Cyprinus carpio) sampled from the Hartbeespoort Dam in South Africa were used for method development. Acetonitrile extraction produced more precise recoveries than hexane extraction. Fluorene and naphthalene were the most abundant PAHs detected in the majority of fish tissues analysed. PAH bioaccumulation in 5-year-old carp and 5-year-old catfish was in the order muscle > kidney > liver > spleen and liver > muscle > kidney > spleen, respectively. PCBs were mostly detected in carp spleen and kidney. Two-year-old carp were analysed to determine PCB and PAH bioaccumulation trends. The differences in ∑16PAH concentrations between the four organs tested were all statistically insignificant for the 3 fish tested (p > 0.05). All other organs with the exception of 5-year-old carp spleen and 5-year-old carp kidney recorded total 31 PCB concentrations (∑31PCB) < 25 ng g-1. Only 5-year-old carp spleen (∑31PCB of 592 ng g-1) and 5-year-old carp kidney (∑31PCB of 561 ng g-1) had significant differences (p < 0.05) from the spleen and kidney in 5-year-old catfish and 2-year-old carp. Whilst the carp and catfish sampled can be considered low PCB risk foods, 5-year-old carp muscle can be considered to be a high PAH risk food, with a benzo(a)pyrene concentration of 7 µg g-1, based on the EU Commission Regulation 2005/208/EC pertaining to the maximum permissible benzo(a)pyrene level in fresh fish muscle.


Assuntos
Carpas/metabolismo , Peixes-Gato/metabolismo , Monitoramento Ambiental , Bifenilos Policlorados/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Bioacumulação , Peixes-Gato/fisiologia , Fígado/metabolismo , Masculino , Músculos/química , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , África do Sul
2.
Dokl Biol Sci ; 487(1): 124-127, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31571081

RESUMO

Weak electric discharges generated by the two species of the African upside-down catfishes, Synodontis sorex and S. batensoda are described. In both species two types of discharges were recorded in the course of aggressive-defense interactions in the pairs of individuals: short simple biphasic and longer (duration >20 ms) discharges with more complex waveform. The discharges of the latter type seem to result from a temporal summation (with various latency) of simple discharges. It is suggested that formation of the long quasimonopolar discharges enhances the coincidence of frequency spectrum of the catfish discharges with maximum sensitivity range of their ampullary electroreceptors.


Assuntos
Peixes-Gato/fisiologia , Órgão Elétrico/fisiologia , Potenciais de Ação , Animais
3.
Arch Anim Nutr ; 73(6): 505-516, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31617788

RESUMO

A growth trial was performed to optimise the inclusion of potassium (K) in feeds of Heteropneustes fossilis (body weight [BW] 6.92 ± 0.1 g). Eight isonitrogenous and isoenergetic diets with varying dietary K levels were prepared by supplementing 0, 1.91, 3.82, 5.73, 7.64, 9.55, 11.46 and 13.37 g KCl/kg basal diet. Analysed dietary K levels were 0.16, 1.12, 2.08, 3.19, 4.18, 5.16, 6.11, 7.14 and 8.16 g/kg dry matter. BW gain, feed conversion ratio (FCR), protein gain (PG) and gill Na+/K+-ATPase activity were best in fish fed 4.18 g K/kg diet. The K concentrations in the whole body and vertebrae increased linearly with the increase up to 5.16 g K/kg diet and reached then a plateau. The K-retention [%] was highest in fish fed the basal diet and decreased with the further inclusion of dietary K up to 2.08 g/kg followed by no change up to diet containing 4.18 g K/kg and then declined further in fish fed higher levels of dietary K. Serum alkaline phosphatase activity was found to increase up to 4.18 g K/kg diet. Regression of BW gain, PG, gill Na+/K+-ATPase and vertebrae K concentration against varying levels of dietary K using broken-line model indicated that an inclusion of 5.44 g K/kg diet is the optimum for maximising growth and mineralisation of H. fossilis.


Assuntos
Peixes-Gato/fisiologia , Proteínas de Peixes/genética , Potássio/metabolismo , ATPase Trocadora de Sódio-Potássio/genética , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Composição Corporal/efeitos dos fármacos , Peixes-Gato/crescimento & desenvolvimento , Dieta/veterinária , Suplementos Nutricionais/análise , Relação Dose-Resposta a Droga , Proteínas de Peixes/metabolismo , Potássio/administração & dosagem , ATPase Trocadora de Sódio-Potássio/metabolismo
4.
Ecotoxicol Environ Saf ; 183: 109584, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446173

RESUMO

There is a dire need to assess the quality of fishes transported for human consumption as lately, their health is challenged because of anthropogenic activities. Heavy metals with a long environmental persistence are toxic to fishes and the humans. The study was conducted to evaluate the impact of heavy metals on Clarias gariepinus inhabiting popular Ganges rivulet at Narora (28.18° E, 78.39° N). The limnological values deviated from the international Standards (USEPA, WHO). Higher total dissolved solids (859 mg/L), total suspended solids (406 mg/L), low dissolved oxygen (5.60 mg/L), and pH (5.21) indicated the presence of contaminants. Heavy metals estimated followed the order Cd > Ni > Cu > Cr. Serum enzymes (hepatic and renal markers) viz., aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were higher than the normal, whereas, creatine kinase (CK) was considerably low in both male and female fish. Stress induced was marked by elevation in cortisol and glucose. This had its impact on hematological parameters as well, as a decline in Total leucocyte count (TLC) & mean corpuscular volume (MCV) and increase in Mean cell hemoglobin (MCH) was observed. Erythrocytes also showed altered morphology. Marked histopathological alterations were observed in all immune organs (head-kidney, liver, spleen, thymus). Oxidative stress induced by heavy metals leads to the production of metal scavenging protein metallothionein (MT) and glutathione peroxidase (GPX). Maximum fold change in metallothionein (MT) gene expression was observed in the liver, followed by spleen, thymus, blood, and head-kidney. Glutathione peroxidase (GPX) gene expression was highest in the liver, followed by thymus, spleen, blood, and head-kidney. The gene expression studies further validated the increased level of heavy metals as potent contaminants of water and the non-condusive abiotic factors.


Assuntos
Peixes-Gato/fisiologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/sangue , Peixes-Gato/genética , Peixes-Gato/imunologia , Dano ao DNA/efeitos dos fármacos , Feminino , Rim/enzimologia , Rim/patologia , Fígado/enzimologia , Fígado/patologia , Masculino , Metais Pesados/análise , Estresse Oxidativo/efeitos dos fármacos , Rios/química , Poluentes Químicos da Água/análise
5.
Fish Physiol Biochem ; 45(5): 1747-1757, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31297679

RESUMO

An 8-week feeding trial was conducted to investigate effects of dietary protein levels (37, 40, and 43%) on the growth performance, feed utilization, digestive enzyme activity, and gene expressions of target of rapamycin (TOR) signaling pathway in fingerling yellow catfish. One hundred and eighty fingerlings (average weight 0.77 ± 0.03 g) were equally distributed across four replicate tanks for each of the three treatments, with 15 fish per tank. No difference (P > 0.05) was observed in initial body weight, survival rate (SR), hepatosomatic index (HSI), viscera index (VSI), dressing percentage (DP), and condition factor (CF) among all the treatments. The diet containing 40% protein increased significantly (P < 0.05) final body weight, weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER), nitrogen retention (NRE), and energy retention (ERE) in fish. The highest protease activity in the stomach and intestine was observed in the P40 group (P < 0.05), while amylase and lipase were not significantly different (P > 0.05). The transcriptional levels of IGF-1, IGF-1R, and Akt were significantly (P < 0.05) higher in fish fed P40 or P43 than those of fish fed P37. TOR and S6K1 mRNA expressions were significantly (P < 0.05) increased in the P40 groups. Hence, the diet containing 40% protein would be suitable for the optimum growth and effective protein utilization of fingerling Pelteobagrus fulvidraco. In vitro, the transcriptional levels of IGF-1, IGF-1R, Akt, TOR, and S6K1 in hepatocyte supplemented with a 40-µM mixed amino acids were significantly (P < 0.05) higher compared to other treatments. No difference (P > 0.05) was observed in eukaryotic translation initiation factor 4E-binding protein 1 in vivo and in vitro among all the treatments. Effects of dietary protein level on growth performance likely are involved in the activation of TOR signaling pathway in fingerling Pelteobagrus fulvidraco.


Assuntos
Peixes-Gato/crescimento & desenvolvimento , Proteínas na Dieta/farmacologia , Digestão/efeitos dos fármacos , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peixes-Gato/fisiologia , Células Cultivadas , Dieta/veterinária , Digestão/fisiologia , Enzimas/genética , Enzimas/metabolismo , Hepatócitos/enzimologia , Hepatócitos/metabolismo , Defeitos do Tubo Neural , Transdução de Sinais
6.
J Therm Biol ; 83: 47-53, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31331524

RESUMO

In the process of selecting and developing freshwater aquaculture species, yellow catfish (Tachysurus fulvidraco) have received widespread attention from Chinese farmers, fishery scientists and technologists. Achieving full artificial breeding of yellow catfish would help improve the quantity and quality of fingerlings supplied for large-scale production of this species. Temperature (T) and dissolved oxygen (DO) are the most important abiotic factors affecting the breeding efficiency of aquatic organisms. In this study, the synergistic effects of T and DO on fertilization rate (FR, %), hatching rate (HR, %) and deformity rate (DR, %) of hybrid yellow catfish (T. fulvidraco♀ × Pseudobagrus vachellii♂) were studied by central composite design (CCD) and response surface methodology. A quadratic regression model for the effects of T and DO on FR, HR and DR was established, and the combination of T and DO was optimized. The first and second order effects of T and DO on FR and HR were significant under the conditions of this experiment (P < 0.05). The first and second order effects of T on DR were significant (P < 0.05) but there was no significant effect of DO on DR (P > 0.05). T and DO had significant interaction effects on FR (P < 0.05). High T and high DO environments reduced FR and HR of yellow catfish eggs and increased DR of the newly hatched larvae. The optimal combination of T and DO was 26.0 °C and 8.3 mgL-1, respectively. Maximum FR and HR coincided with minimal DR whose predicted values were 87.2%, 89.1% and 2.7%, respectively, with reliability of 0.979. Maintaining T and DO in the best combination will help to improve breeding efficiency and ensure production of the highest quantity and quality of fingerlings.


Assuntos
Peixes-Gato/fisiologia , Desenvolvimento Embrionário , Fertilização , Modelos Teóricos , Oxigênio/efeitos adversos , Temperatura Ambiente , Animais , Peixes-Gato/embriologia , Peixes-Gato/genética , Hibridização Genética
7.
Ecotoxicol Environ Saf ; 182: 109438, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31310901

RESUMO

The nonsteroidal anti-inflammatory drugs (NSAIDs) are amongst the most commonly detected classes of pharmaceuticals in freshwater environments, with paracetamol being the most abundant. The aim of this study was to evaluate the possible toxic effects of environmentally relevant concentrations (0.25, 2.5 and 25 µg.L-1) of paracetamol in Rhamdia quelen fish exposed for 14 days using different biomarkers. The total count of leukocytes and thrombocytes was reduced at the highest concentration. In the gills, all concentrations of paracetamol reduced the glutathione S-transferase (GST) activity and the reduced glutathione (GSH) levels compared to the control group. The activity of catalase (CAT) was not altered and glutathione peroxidase (GPx) activity increased at the highest concentrations. The superoxide dismutase (SOD) activity decreased at 25 µg.L-1 and the LPO levels increased at 2.5 µg.L-1 when compared to the control group. The concentration of ROS was not different among the groups. In the posterior kidney the activities of GST (2.5 µg.L-1), CAT (2.5 µg.L-1 and at 25 µg. L-1) and GPx and GSH levels increased at all concentrations when compared to the control group. The SOD activity and LPO levels did not change. Paracetamol caused genotoxicity in the blood and gills at concentrations of 2.5 µg.L-1 and in the posterior kidney at 2.5 and 25 µg.L-1. An osmoregulatory imbalance in plasma ions and a reduction in the carbonic anhydrase activity in the gills at 0.25 µg.L-1 were observed. Histopathological alterations occurred in the gills of fish exposed to 25 µg.L-1 and in the posterior kidney at 0.25 and 25 µg.L-1 of paracetamol. The integrated biomarker index showed that the stress caused by the concentration of 25 µg.L-1 was the highest one. These results demonstrated toxic effects of paracetamol on the gills and posterior kidneys of fish, compromising their physiological functions and evidencing the need for monitoring the residues of pharmaceuticals released into aquatic environment.


Assuntos
Acetaminofen/toxicidade , Peixes-Gato/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Anti-Inflamatórios não Esteroides , Biomarcadores/metabolismo , Catalase , Dano ao DNA , Brânquias/efeitos dos fármacos , Glutationa/farmacologia , Glutationa Peroxidase , Glutationa Transferase
8.
Fish Physiol Biochem ; 45(5): 1627-1647, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31161532

RESUMO

The 56-day feeding trial was carried out to investigate the effects of dietary tryptophan (Trp) on growth performance, digestive and absorptive enzyme activities, intestinal antioxidant capacity, and appetite and GH-IGF axis-related genes expression of hybrid catfish (Pelteobagrus vachelli♀ × Leiocassis longirostris♂). A total of 864 hybrid catfish (21.82 ± 0.14 g) were fed six different experimental diets containing graded levels of Trp at 2.6, 3.1, 3.7, 4.2, 4.7, and 5.6 g kg-1 diet. The results indicated that dietary Trp increased (P < 0.05) (1) final body weight, percent weight gain, specific growth rate, feed intake, feed efficiency, and protein efficiency ratio; (2) fish body protein, lipid and ash contents, protein, and ash production values; (3) stomach weight, stomach somatic index, liver weight, intestinal weight, length and somatic index, and relative gut length; and (4) activities of pepsin in the stomach; trypsin, chymotrypsin, lipase, and amylase in the pancreas and intestine; and γ-glutamyl transpeptidase, Na+, K+-ATPase, and alkaline phosphatase in the intestine. Dietary Trp decreased malondialdehyde content, increased antioxidant enzyme activities and glutathione content, but downregulated Keap1 mRNA expression, and upregulated the expression of NPY, ghrelin, GH, GHR, IGF1, IGF2, IGF1R, PIK3Ca, AKT1, TOR, 4EBP1, and S6K1 genes. These results indicated that Trp improved hybrid catfish growth performance, digestive and absorptive ability, antioxidant status, and appetite and GH-IGF axis-related gene expression. Based on the quadratic regression analysis of PWG, SGR, and FI, the dietary Trp requirement of hybrid catfish (21.82-39.64 g) was recommended between 3.96 and 4.08 g kg-1 diet (9.4-9.7 g kg-1 of dietary protein).


Assuntos
Apetite/efeitos dos fármacos , Peixes-Gato/genética , Peixes-Gato/fisiologia , Cruzamentos Genéticos , Intestinos/efeitos dos fármacos , Triptofano/farmacologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antioxidantes/metabolismo , Dieta/veterinária , Digestão/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like II/genética , Fator de Crescimento Insulin-Like II/metabolismo , Intestinos/enzimologia , Intestinos/fisiologia , Triptofano/administração & dosagem
9.
An Acad Bras Cienc ; 91(2): e20180131, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31038530

RESUMO

Hypostomus commersoni Valenciennes 1836, Hypostomus cordovae (Günther 1880) and Hypostomus laplatae (Eigenmann 1907) have been little studied since their original descriptions. This study shows a comprehensive review of these species from the Lower La Plata Basin, including their taxonomic history, distribution, color patterns, morphology, and ecological and molecular phylogenetic data. Morphological and phylogenetic analyses based on D-loop sequences suggested that H. commersoni can be separated into two subclades, or subgroups. Based on these results and on the non-overlapping distribution range of the two subclades, we conclude that they represent two distinct species, thereby revalidating H. spiniger. The results also suggest that H. paranensis should be considered as species inquirenda and H. cordovae as valid species. This integrated approach provides key information for assessing the conservation status and biogeographic aspects of the genus Hypostomus in the Lower La Plata Basin.


Assuntos
Biodiversidade , Peixes-Gato/anatomia & histologia , Animais , Argentina , Peixes-Gato/genética , Peixes-Gato/fisiologia , Geografia , Filogenia , Especificidade da Espécie
10.
Gene ; 703: 35-49, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-30953708

RESUMO

The facultative air-breathing magur catfish (Clarias magur) frequently face different environmental challenges, such as hyper-ammonia, and desiccation stresses in their natural habitats. All these stresses lead to higher accumulation of body ammonia, thereby causing various harmful effects to the fish due to its toxicity. Nonetheless, the mechanisms underlying ammonia-induced toxicity is yet not clear. In the present study, we used RNA sequencing and utilized a modified method for de novo assembly of the transcriptome to provide an exhaustive study on the transcriptomic alterations of magur catfish in response to high environmental ammonia (HEA; 25 mM NH4Cl). The final contig assembly produced a total of 311,076 unique transcripts (termed as unigenes) with a GC content of 48.3% and the average length of 599 bp. A considerable number of SSR marker associated with these unigenes were also detected. A total of 279,156 transcripts were successfully annotated by using various databases. Comparative transcriptomic analysis revealed a total of 3453 and 19,455 genes were differentially expressed in the liver and brain tissues, respectively, in ammonia-treated fish compared to the control. Enrichment analysis of the differentially expressed genes (DEGs) showed that several GO and KEGG pathway terms were significantly over-represented. Functional analysis of significantly elevated DEGs demonstrated that ammonia stress tolerance of the magur catfish was associated with quite a few pathways related to immune response, oxidative stress, and apoptosis, as well as few transporter proteins involved with ammonia and urea transport. Both liver and brain tissues showed HEA-mediated oxidative damage with consequent activation of antioxidant machinery. However, elevated ROS levels led to an activation of inflammatory cytokines and thus innate immune response in the liver. Conversely, in the brain ROS-mediated irreversible cell damages activated apoptosis via both p53-Bax-Bcl2 and caspase-mediated pathways. The present study provides a novel understanding of the molecular responses of this air-breathing catfish against the ammonia-induced stressors, which could elucidate the underlying mechanisms of adaptation of this facultative air-breather living under various environmental constraints.


Assuntos
Amônia/toxicidade , Peixes-Gato/fisiologia , Proteínas de Peixes/genética , Perfilação da Expressão Gênica/métodos , Adaptação Fisiológica , Animais , Composição de Bases , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Peixes-Gato/genética , Mapeamento de Sequências Contíguas , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Análise de Sequência de RNA/métodos
11.
J Fish Biol ; 95(2): 633-637, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30963582

RESUMO

The genetic analysis of Brachyplatystoma platynemum individuals sampled from the lower Madeira River reinforces the existence of two structured populations in the Amazon Basin (Madeira and Amazon populations). However, the recapture of an individual from the Amazon population in the Solimões River, which was telemetry-tagged in the Madeira River after the damming, indicates that fish from the Amazon population move between the two river systems. This has not yet been observed, however, in the Madeira River population, which is currently divided and isolated in the lower and upper Madeira River by the construction of two dams.


Assuntos
Peixes-Gato/genética , Telemetria/veterinária , Animais , Brasil , Peixes-Gato/classificação , Peixes-Gato/fisiologia , Citocromos b/genética , DNA/química , DNA/isolamento & purificação , Haplótipos/genética , Peptídeos Cíclicos/genética , Rios , Telemetria/métodos
12.
Acta Histochem ; 121(4): 437-449, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30952366

RESUMO

Lepidophagy is comparatively rare amongst teleost fishes, yet our understanding of this specialization is lacking. Therefore we examined the digestive tract features of Pachypterus khavalchor using morphological, osteological, histological and histochemical techniques to comprehend and relate structural organization of digestive tract with scale eating habit. Morphologically, the alimentary canal is defined by a short and muscular esophagus, well-developed stomach and comparatively short intestine. Gut content analysis and intestinal coefficient value (0.53 ± 0.01) revealed that P. khavalchor exhibit both carnivory and lepidophagy. However, P. khavalchor primarily feeds on the scales (67.47%) and other chitin-rich material like aquatic insects (17.62%), aquatic larvae (8.66%) which affirms its solid association with chitinase producing endosymbionts in the gut. Lepidophagy is further supported by the osteological observations. The perfect segregation of the functions such as food capture, ingestion and processing amongst the different types of teeth located in the oral cavity and pharyngeal region thus could be taken as evolutionary adaptations in scale eaters to support lepidophagy. Specialized arrangement of the esophageal and stomach epithelial folds could be altogether taken as an adaptation with the end goal to frame the scale stacks and accordingly facilitate the handling and processing of chitin-rich bolus. The esophageal mucosa is simple squamous epithelium instead of stratified epithelium with numerous goblet cells to withstand the mechanical harm by hard-food stuff like scales. The cardiac and fundic regions exhibited large number tubular gastric glands with simple columnar epithelium. Surface cells of all three stomach regions stained positive for PAS staining. The intestine is without pyloric caeca and is divided into anterior and posterior region. Histologically it is characterized by simple columnar epithelium with brush border and numerous goblet cells throughout its length. Presence of large number microvilli on anterior and posterior intestine was noticeable. Intestinal goblet cells reacted positively to PAS, AB (pH 1) and AB (pH 2.5). Secretions of goblet cells are important for lubricating and protecting the epithelium. The results of present investigation improve the understanding of the digestive physiology of scale eaters in general and P. khavalchor in particular. Overall, our data indicates that though P. khavalchor predominantly feeds on scale, the digestive physiology is adapted to support dual feeding habit (lepidophagy and carnivory).


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/fisiologia , Comportamento Alimentar/fisiologia , Trato Gastrointestinal/anatomia & histologia , Trato Gastrointestinal/fisiologia , Animais , Peixes-Gato/metabolismo , Quitina/metabolismo , Feminino , Mucinas Gástricas/metabolismo , Células Caliciformes/citologia , Células Caliciformes/fisiologia , Masculino
13.
Philos Trans R Soc Lond B Biol Sci ; 374(1769): 20180205, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30967083

RESUMO

The cuckoo catfish, Synodontis multipunctatus, is the only known obligate brood parasite among fishes, exploiting the parental care of mouthbrooding cichlids endemic to Lake Tanganyika. Comparisons of this system to brood parasitism in birds may reveal broader principles that underlie the evolution of this life-history strategy in vertebrates. However, little is known about the features of the cuckoo catfish that enable this species to successfully parasitize cichlids. Here, we examine early ontogeny of the cuckoo catfish and compare it to that of its cichlid hosts as well as a non-parasitic congener. We found that cuckoo catfish embryos develop and hatch in advance of host embryos, and begin feeding on cichlid young just as they start to hatch. Overall timing of ontogeny in the cuckoo catfish was found to be similar to that of the substrate-spawning congener Synodontis lucipinnis, suggesting that more rapid development of the cuckoo catfish relative to cichlids is not a unique adaptation to brood parasitism. However, we found that cuckoo catfish progeny exhibit extensive morphological differences from S. lucipinnis, which may represent adaptations to brood parasitism. These life-history observations reveal both similarities and differences between the cuckoo catfish system and brood parasitism in other lineages. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.


Assuntos
Peixes-Gato/fisiologia , Ciclídeos/parasitologia , Interações Hospedeiro-Parasita , Traços de História de Vida , Adaptação Biológica , África , Animais , Lagos
14.
Philos Trans R Soc Lond B Biol Sci ; 374(1769): 20180412, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30967084

RESUMO

Interspecific brood parasitism occurs in several independent lineages of birds and social insects, putatively evolving from intraspecific brood parasitism. The cuckoo catfish, Synodontis multipunctatus, the only known obligatory non-avian brood parasite, exploits mouthbrooding cichlid fishes in Lake Tanganyika, despite the absence of parental care in its evolutionary lineage (family Mochokidae). Cuckoo catfish participate in host spawning events, with their eggs subsequently collected and brooded by parental cichlids, though they can later be selectively rejected by the host. One scenario for the origin of brood parasitism in cuckoo catfish is through predation of cichlid eggs during spawning, eventually resulting in a spatial and temporal match in oviposition by host and parasite. Here we demonstrate experimentally that, uniquely among all known brood parasites, cuckoo catfish have the capacity to re-infect their hosts at a late developmental stage following egg rejection. We show that cuckoo catfish offspring can survive outside the host buccal cavity and re-infect parental hosts at a later incubation phase by exploiting the strong parental instinct of hosts to collect stray offspring. This finding implies an alternative evolutionary origin for cuckoo catfish brood parasitism, with the parental response of host cichlids facilitating its evolution. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.


Assuntos
Peixes-Gato/fisiologia , Ciclídeos/parasitologia , Interações Hospedeiro-Parasita , Animais , Peixes-Gato/crescimento & desenvolvimento , Feminino , Comportamento de Nidação
15.
Cryobiology ; 87: 32-39, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30876909

RESUMO

Lipid rafts and associated membrane proteins (flotillin, caveolin) play important roles in cell signaling and sperm fertilization while heat shock proteins (Hsp) ensure properly protein folding to fulfill their physiological functions. The markedly reduced fertility in thawed sperm after cryopreservation could result from disrupted membrane lipid rafts and these proteins. To explore the effect of sperm cryopreservation on lipid rafts and heat shock proteins, we compared lipid raft integrity, and the expression levels of lipid raft associated proteins (Flot-1, Flot-2, Cav-1) as well as heat shock proteins (Hsp90, Hsp70) in fresh and thawed sperm cryopreserved under different scenarios in yellow catfish. We found higher lipid raft integrity, higher protein expression levels of Flot-1, Flot-2, Cav-1, Hsp90, and Hsp70 in fresh sperm samples than in thawed sperm samples, in thawed sperm samples cryopreserved with optimal cooling rate than those cryopreserved with sub-optimal cooling rate, and in thawed sperm samples cryopreserved with extenders supplemented with cholesterol than those supplemented with methyl-ß-cyclodextrin (for cholesterol removal). Our findings indicate that lipid raft integrity, and expression levels of Flot-1, Flot-2, Cav-1, Hsp90, and Hsp70 are clearly associated with sperm quality, and together they may play a cumulative role in reduced fertility associated with thawed sperm in aquatic species.


Assuntos
Caveolinas/metabolismo , Criopreservação/métodos , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Microdomínios da Membrana/metabolismo , Proteínas de Membrana/metabolismo , Animais , Peixes-Gato/fisiologia , Colesterol/farmacologia , Masculino , Análise do Sêmen , Transdução de Sinais , Motilidade Espermática/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos
16.
Sci Total Environ ; 668: 104-114, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-30852190

RESUMO

The rising level of triclosan (TCS) in aquatic environment is raising concerns and in this context, evaluation of toxicity towards aquatic organisms under varying environmental conditions, especially temperature, is a pre-requisite for a better understanding of the toxic effects on specific metabolic processes. In this report, the mechanistic physiological responses of fish towards varying concentration of TCS at graded temperature were evaluated. The static renewal acute test was performed, and 96 h median lethal concentration (LC50) of TCS for Pangasianodon hypophthalmus was estimated and the values were 848.33, 1181.94 and 1356.96 µg L-1 at 25, 30 and 35 °C respectively. The chronic study was performed for 30 days at 1/5th and 1/10th concentration of the estimated LC50 of TCS at 25, 30 and 35 °C respectively. The chronic effects resulted in significant decrease in total erythrocyte count (TEC), hemoglobin (Hb), packed cell volume (PCV), mean corpuscular hemoglobin (MCH) and mean cell volume (MCV), while a significant increase in total leukocyte count (TLC), mean corpuscular hemoglobin concentration (MCHC) and red cell distribution width (RDW) was observed in TCS exposed groups at 25-35 °C. Further, a significant increase in activity of transaminase enzymes, lactate dehydrogenase (LDH) and antioxidant enzymes (superoxide dismutase) (SOD) and catalase (CAT) except glutathione-S-transferase (GST) in liver and acetylcholinesterase (AChE) in brain of the TCS exposed fish was recorded in all the above temperature range. Severe damage of DNA in nucleus of blood and liver cells, and high micronuclei frequency (MNi) was noticed in TCS exposed groups at 25 °C. The report provides convincing evidence for the effect of temperature on TCS toxicity. The findings will help in gaining a better insight into the change in toxicity of TCS in a natural environment where diurnal variations in temperature may be crucial in determining the overall extent of toxicity.


Assuntos
Peixes-Gato/fisiologia , Testes de Mutagenicidade , Triclosan/toxicidade , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Dano ao DNA , Glutationa Transferase/metabolismo , Superóxido Dismutase/metabolismo
17.
PLoS One ; 14(3): e0207328, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30860994

RESUMO

Hypostomus subcarinatus Castelnau, 1855 is rediscovered in the Lagoa da Pampulha, an urban lake in the Rio das Velhas basin (Rio São Francisco system) in the state of Minas Gerais, southeastern Brazil. Herein, H. subcarinatus is redescribed and diagnosed from its congeners based on characters such as blue-tan dorsal fin in live specimens, slender bicuspid teeth, dentaries angled more than 90 degrees, moderate keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, by having nuptial odontodes mainly on pectoral, dorsal and caudal-fin rays, and long anal-fin unbranched ray. The rediscovery of H. subcarinatus more than 160 years after its original description was an unexpected event, because the Lagoa da Pampulha is an artificial, silted and polluted urban lake. The lake is located in downtown Belo Horizonte, the third largest urban agglomeration in Brazil with a population exceeding 5.9 million inhabitants.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/fisiologia , Conservação dos Recursos Naturais , Ecossistema , Espécies em Perigo de Extinção , Animais , Brasil , Peixes-Gato/classificação
18.
Environ Sci Pollut Res Int ; 26(11): 10800-10815, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30778947

RESUMO

The Batchwa vacha, Eutropiichthys vacha is commercially important, supporting a viable small- and large-scale fishery throughout the Ganges River, NW Bangladesh. This study provides detail information on reproduction of E. vacha including size at sexual maturity, spawning and peak spawning season, and fecundity based on 734 female specimens through regular monthly sampling using cast net, gill net, and square lift net in the Ganges River during January to December 2016. Also, our study estimated the effects of climate change including temperature and rainfall on reproduction of E. vacha in the Ganges River. For each individual, lengths (total length, TL; standard length, SL) and body weight (BW) were measured with slide caliper and digital balance, respectively. Gonads (ovaries) were collected carefully by ventral dissection of each female specimen and weighed to the nearest 0.01 g accuracy. The gonadosomatic index (GSI % = (GW/BW) ×100), modified gonadosomatic index (MGSI % = (GW/BW - GW) × 100), and Dobriyal index (DI = [Formula: see text]) were calculated to estimate the size at sexual maturity (L50) and spawning season. Based on GSI, MGSI, and DI, the L50 was calculated as 12.5 cm TL for female. The TL50, the TL at which 50% of individuals become mature, was calculated by logistic equation as 12.7 cm. Also, on the basis of higher values of GSI, MGSI, and DI, spawning season was ranged from April to August, with the peak in June-July, signifying the peak spawning season for E. vacha in the Ganges River. The total fecundity (FT) ranged from 4800 to 77,976 (mean ± SD, 31384 ± 23,747) and was highly correlated with TL and BW. Water temperature during the spawning period ranged from 28 to 34 °C, with an average of 31 °C and there was significant correlation between temperature and GSI. Also, the spawning season coincides with the peak rainfall and there was significant correlation between rainfall and GSI. Additionally, analysis of long data series indicated that annual average air temperature is increasing by 0.0258 °C/year, while the annual average rainfall is decreasing by 3.107 mm/year. Finally, the findings of this study would be very effective to impose specific management for E. vacha in the Ganges River and surrounding ecosystems.


Assuntos
Peixes-Gato/crescimento & desenvolvimento , Mudança Climática , Reprodução/fisiologia , Rios/química , Maturidade Sexual/fisiologia , Animais , Bangladesh , Peso Corporal , Peixes-Gato/fisiologia , Ecossistema , Feminino , Pesqueiros , Masculino , Dinâmica Populacional , Estações do Ano , Temperatura Ambiente
19.
Chemosphere ; 223: 124-130, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30772591

RESUMO

The objective of this study was to evaluate whether antiparasitic eprinomectin may be an environmental contaminant in water compartment in low concentrations, negatively affecting neurotransmission and, consequently, the natural behavior of the jundiá (Rhamdia quelen). Fish were randomly allocated in tanks and exposed for 24 and 48 h to eprinomectin concentrations in water [0.0 (Control), 1.124 (T1), 1.809 (T2) and 3.976 (T3) µg L-1], followed by 48 h of recovery in eprinomectin-free water, in order to evaluate the behavioral parameters, levels of reactive oxygen species (ROS) in the brain, as well as cerebral enzymatic activities of acetylcholinesterase (AChE) and of the sodium-potassium ATPase pump (Na+/K+-ATPase). Especially at the two highest concentrations of eprinomectin (T2 and T3), the fish showed alterations in natural behavior, particularly hyperlocomotion and longer time on the surface. Furthermore, at these same concentrations, cerebral ROS levels increased and cerebral AChE activity decreased. At the highest concentration (T3) cerebral Na+/K+-ATPase activity was reduced. Increased ROS and impairment of AChE and Na+/K+-ATPase enzymes in the brain may have contributed directly to behavioral changes, due to neuronal damage and synapse impairment. Even after 48 h in water without eprinomectin, behavioral changes and neurotoxic effects were observed in fish, suggesting residual effects of the antiparasitic. In conclusion, eprinomectin even in low concentrations may be a hazardous environmental contaminant for aquatic organisms, as it causes brain damage and affects the natural behavior of fish.


Assuntos
Acetilcolinesterase/efeitos dos fármacos , Peixes-Gato/fisiologia , Ivermectina/análogos & derivados , ATPase Trocadora de Sódio-Potássio/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/enzimologia , Inibidores da Colinesterase , Ivermectina/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/toxicidade
20.
J Therm Biol ; 80: 133-140, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30784477

RESUMO

The present study evaluates whether increased water temperature induces reproduction by Lophiosilurus alexandri under controlled conditions, and investigates the effects of this procedure on sexual steroids, hematological profile and behavior. A 44-week experiment was performed with four wild males and 12 wild females that had been acclimatized to captive conditions. Water temperature was maintained at 24.4 ±â€¯1.0 °C for weeks 1-22, and then at 29.0 ±â€¯1.1 °C for weeks 22-44. Spawn weight, number of eggs/spawn and hatching rate were satisfactory and ranged 27.5-127.5 g, 1209-5183 and 83-89%, respectively. Hematocrit, leukocytes and glucose were not influenced by increased water temperature, while higher values for erythrocytes were observed for both sexes. The lowest value for plasma protein was for females maintained at 29.0 °C, while the lowest value for testosterone was obtained at the end of the study period at a temperature in 29.0 °C. Serum values of 17ß-estradiol were higher in females than in males, however, there was no evidence of variation as a function of experimental temperature or interaction with sex. The reproductive behavior of L. alexandri in captivity is described for the first time. The present study demonstrates that adult individuals are able to maintain a stable hematological profile during an increase in mean water temperature from 24.4 °C to 29.0 °C, even during the reproductive period, and still produce good quality larvae. Nonetheless, whether spawning was associated with increased 17ß-estradiol levels could not be determined.


Assuntos
Peixes-Gato/fisiologia , Reprodução , Temperatura Ambiente , Aclimatação , Animais , Comportamento Animal , Proteínas Sanguíneas/metabolismo , Contagem de Eritrócitos , Estradiol/sangue , Feminino , Masculino , Testosterona/sangue
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