RESUMO
Abstract Untreated sewage and industrial wastes from Faisalabad city are disposed to River Chenab through Chakbandi Main Drain (CMD). The present project is planned to investigate the effects of this freshwater pollution on the body of fish Ictalurus punctatus. The specimens of this fish species were collected upstream and downstream of the entrance of CMD into River Chenab. Fish gills, liver, kidney and muscles from dorsolateral regions of fish were subjected to histopathology. Farmed fish and fish from upstream areas were used as control. Fish collected from polluted experimental sites showed significant damage in selected organs. Gill tissues showed an abnormality in the form of an uplifting of the primary epithelium, fusion, vacuolation, hypertrophy, and necrosis. While liver tissues subjected to hepatocytes degeneration, necrosis, mitochondrial granular hepatocyte, and sinusoids dilation. Kidney tissues indicated increased bowmen space and constricted glomerulus and degenerated nephrons. Edema, necrosis, and atrophy were observed in muscle tissues of fish from polluted areas. Fish from the upstream area showed fused gill lamellae, inflammatory cell infiltration, hypertrophy and vacuolation in hepatocytes. Kidney tissues indicated the presence of nuclear tubular cells, destructive renal tubules, hemorrhage, and necrosis at tubular epithelium. Intra myofibril spaces were also observed in muscles. Specimens of control fish indicated no variation in gills, liver, kidney, and muscles. The present study revealed a strong correlation between the degree of tissue damage and environmental contamination. Present findings also compel global warnings to protect our water bodies and fish to rescue the human population.
Resumo O esgoto não tratado e os resíduos industriais da cidade de Faisalabad, no Paquistão, são descartados no Rio Chenab através do dreno principal de Chakbandi (CMD). O presente projeto busca investigar os efeitos dessa poluição de água doce no corpo de peixes Ictalurus punctatus. Os espécimes deste peixe foram coletados a montante e a jusante da entrada do CMD no Rio Chenab. Brânquias, fígado, rim e músculos das regiões dorsolaterais dos peixes foram submetidos à histopatologia. Peixes de criação e peixes de áreas a montante foram utilizados como controle. Peixes coletados em locais experimentais poluídos mostraram danos significativos em órgãos selecionados. Os tecidos branquiais mostraram uma anormalidade na forma de elevação do epitélio primário, fusão, vacuolação, hipertrofia e necrose. Observou-se que os tecidos hepáticos estão sujeitos a degeneração de hepatócitos, necrose, hepatócitos mitocondriais granulares e dilatação de sinusoides. Os tecidos renais indicaram aumento do espaço dos arqueiros, glomérulos contraídos e néfrons degenerados. Edema, necrose e atrofia foram observados nos tecidos musculares de peixes de áreas poluídas. Peixes da área a montante apresentaram lamelas branquiais fundidas, infiltração de células inflamatórias, hipertrofia e vacuolização em hepatócitos. Os tecidos renais indicaram a presença de células tubulares nucleares, túbulos renais destrutivos, hemorragia e necrose no epitélio tubular. Os espaços intramiofibrilas também foram observados nos músculos. Amostras de peixes controle não indicaram variação em brânquias, fígado, rim e músculos. O presente estudo revelou uma forte correlação entre o grau de dano tecidual e a contaminação ambiental. As descobertas atuais também constituem avisos globais para proteger nossos corpos d'água e peixes para resguardar a população humana.
Assuntos
Humanos , Animais , Poluentes Químicos da Água , Ictaluridae , Brânquias , Rim , Fígado , MúsculosRESUMO
Untreated sewage and industrial wastes from Faisalabad city are disposed to River Chenab through Chakbandi Main Drain (CMD). The present project is planned to investigate the effects of this freshwater pollution on the body of fish Ictalurus punctatus. The specimens of this fish species were collected upstream and downstream of the entrance of CMD into River Chenab. Fish gills, liver, kidney and muscles from dorsolateral regions of fish were subjected to histopathology. Farmed fish and fish from upstream areas were used as control. Fish collected from polluted experimental sites showed significant damage in selected organs. Gill tissues showed an abnormality in the form of an uplifting of the primary epithelium, fusion, vacuolation, hypertrophy, and necrosis. While liver tissues subjected to hepatocytes degeneration, necrosis, mitochondrial granular hepatocyte, and sinusoids dilation. Kidney tissues indicated increased bowmen space and constricted glomerulus and degenerated nephrons. Edema, necrosis, and atrophy were observed in muscle tissues of fish from polluted areas. Fish from the upstream area showed fused gill lamellae, inflammatory cell infiltration, hypertrophy and vacuolation in hepatocytes. Kidney tissues indicated the presence of nuclear tubular cells, destructive renal tubules, hemorrhage, and necrosis at tubular epithelium. Intra myofibril spaces were also observed in muscles. Specimens of control fish indicated no variation in gills, liver, kidney, and muscles. The present study revealed a strong correlation between the degree of tissue damage and environmental contamination. Present findings also compel global warnings to protect our water bodies and fish to rescue the human population.(AU)
O esgoto não tratado e os resíduos industriais da cidade de Faisalabad, no Paquistão, são descartados no Rio Chenab através do dreno principal de Chakbandi (CMD). O presente projeto busca investigar os efeitos dessa poluição de água doce no corpo de peixes Ictalurus punctatus. Os espécimes deste peixe foram coletados a montante e a jusante da entrada do CMD no Rio Chenab. Brânquias, fígado, rim e músculos das regiões dorsolaterais dos peixes foram submetidos à histopatologia. Peixes de criação e peixes de áreas a montante foram utilizados como controle. Peixes coletados em locais experimentais poluídos mostraram danos significativos em órgãos selecionados. Os tecidos branquiais mostraram uma anormalidade na forma de elevação do epitélio primário, fusão, vacuolação, hipertrofia e necrose. Observou-se que os tecidos hepáticos estão sujeitos a degeneração de hepatócitos, necrose, hepatócitos mitocondriais granulares e dilatação de sinusoides. Os tecidos renais indicaram aumento do espaço dos arqueiros, glomérulos contraídos e néfrons degenerados. Edema, necrose e atrofia foram observados nos tecidos musculares de peixes de áreas poluídas. Peixes da área a montante apresentaram lamelas branquiais fundidas, infiltração de células inflamatórias, hipertrofia e vacuolização em hepatócitos. Os tecidos renais indicaram a presença de células tubulares nucleares, túbulos renais destrutivos, hemorragia e necrose no epitélio tubular. Os espaços intramiofibrilas também foram observados nos músculos. Amostras de peixes controle não indicaram variação em brânquias, fígado, rim e músculos. O presente estudo revelou uma forte correlação entre o grau de dano tecidual e a contaminação ambiental. As descobertas atuais também constituem avisos globais para proteger nossos corpos d'água e peixes para resguardar a população humana.(AU)
Assuntos
Animais , Ictaluridae/anormalidades , Esgotos/efeitos adversos , Poluição Ambiental/efeitos adversosRESUMO
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.
Assuntos
Peixes-Gato , Infecções por Enterobacteriaceae , Doenças dos Peixes , Ictaluridae , Animais , Brasil , Edwardsiella ictaluri , Infecções por Enterobacteriaceae/veterinária , Espécies IntroduzidasRESUMO
Untreated sewage and industrial wastes from Faisalabad city are disposed to River Chenab through Chakbandi Main Drain (CMD). The present project is planned to investigate the effects of this freshwater pollution on the body of fish Ictalurus punctatus. The specimens of this fish species were collected upstream and downstream of the entrance of CMD into River Chenab. Fish gills, liver, kidney and muscles from dorsolateral regions of fish were subjected to histopathology. Farmed fish and fish from upstream areas were used as control. Fish collected from polluted experimental sites showed significant damage in selected organs. Gill tissues showed an abnormality in the form of an uplifting of the primary epithelium, fusion, vacuolation, hypertrophy, and necrosis. While liver tissues subjected to hepatocytes degeneration, necrosis, mitochondrial granular hepatocyte, and sinusoids dilation. Kidney tissues indicated increased bowmen space and constricted glomerulus and degenerated nephrons. Edema, necrosis, and atrophy were observed in muscle tissues of fish from polluted areas. Fish from the upstream area showed fused gill lamellae, inflammatory cell infiltration, hypertrophy and vacuolation in hepatocytes. Kidney tissues indicated the presence of nuclear tubular cells, destructive renal tubules, hemorrhage, and necrosis at tubular epithelium. Intra myofibril spaces were also observed in muscles. Specimens of control fish indicated no variation in gills, liver, kidney, and muscles. The present study revealed a strong correlation between the degree of tissue damage and environmental contamination. Present findings also compel global warnings to protect our water bodies and fish to rescue the human population.
Assuntos
Ictaluridae , Poluentes Químicos da Água , Animais , Brânquias , Humanos , Rim , Fígado , MúsculosRESUMO
Introduction: Morphotypes of native catfish of the genus Ictalurus (Siluriformes: Ictaluridae) are known to occur in allopatry in the northern Sierra Madre Occidental of Mexico, with only the Yaqui catfish (Ictalurus pricei) taxonomically described. Recent genetic analysis of these morphotypes has revealed the monophyly of the I. pricei complex, which indicates Ictalurus sp. from the Culiacán River and San Lorenzo River basins as its nearest genetic relative and recognizes as an evolutionarily significant unit the Culiacán River and San Lorenzo River morphotypes. Objective: To compare the meristic and morphometric characteristics of the catfish of the Culiacán River basin with its nearest genetic relative, the Yaqui catfish, in order to determine the presence of distinctive morphological characters that support genetic evidence previously reported for these morphotypes. Methods: Catfish specimens were collected during various field expeditions (1990-2012) to remote sites of the Sierra Madre Occidental and conducted in the Yaqui River and Culiacán River basins with the purpose of morphological comparison. Forty-five morphological characters (40 morphometric and five meristic) were examined in 76 adult specimens - 52 Ictalurus sp. and 24 Ictalurus pricei. Three groups were subject to a discriminant function analysis (DFA), including two Ictalurus sp. groups from the Humaya River and Tamazula River sub-basins, representing the Culiacán River basin, and one I. pricei group representing the Yaqui River basin. The standardized measurements and meristic data of the catfish morphotypes were compared by means of DFA. Results: The DFA revealed 12 characters to be significantly different (P< 0.01) among the groups compared. The morphological characters separating the Ictalurus sp. (Culiacán River basin) from the Yaqui catfish were associated with lower anal, pelvic and pectoral fin ray numbers, shorter head and predorsal lengths, shorter longest lateral barbel and longest dorsal ray lengths and a narrower premaxilar dentary plate; and finally longer distances in Ictalurus sp. for dorsal-fin origin to last anal-fin ray base and dorsal-fin origin to posterior end of the adipose fin base. The standardized coefficients for canonical variables 1 and 2 accounted for 85.6 % and 14.4 % of the total variation, respectively. Conclusions: The distinctive morphological characters of the Ictalurus sp. found in the Culiacán River basin, combined with the known mitochondrial evidence for this morphotype, identify it as an evolutionarily significant unit that requires description as a new species based on taxonomical protocols.
Introducción: Morfotipos de bagres nativos del género Ictalurus (Siluriformes: Ictaluridae) se distribuyen de manera alopátrica en el norte de la Sierra Madre Occidental, de los cuales solo el bagre Yaqui (Ictalurus pricei) ha sido taxonómicamente descrito. Análisis genéticos recientes de esos morfotipos han revelado la monofilia del complejo I. pricei, que incluyó a Ictalurus sp. de las cuencas de los ríos Culiacán y San Lorenzo como su pariente genético más cercano, además del reconocimiento de los morfotipos de los ríos Culiacán and San Lorenzo como una unidad evolutivamente significativa. Objetivo: Comparar características merísticas y morfométricas del bagre de la cuenca del río Culiacán con su pariente genético más cercano, el bagre Yaqui, con el propósito de determinar la presencia de caracteres morfológicos distintivos en apoyo a evidencia genética previamente reportada para esos morfotipos. Métodos: Especímenes de bagres fueron recolectados durante varias expediciones de campo (1990-2012) en sitios remotos de la Sierra Madre Occidental en las cuencas de los ríos Yaqui y Culiacán para comparación morfológica. Cuarenta y cinco caracteres morfológicos (40 morfométricos y cinco merísticos) fueron examinados en 76 especímenes adultos (52 de Ictalurus sp. y 24 de Ictalurus pricei). Medidas corporales estandarizadas y datos merísticos de los morfotipos de bagres estudiados fueron comparados por medio de un análisis de función discriminante (AFD). Resultados: El AFD arrojó 12 caracteres significativamente diferentes (P< 0.01) entre los grupos comparados. Los caracteres morfológicos que distinguen al bagre del río Culiacán del bagre Yaqui, estuvieron asociados con un menor número de radios anales, pélvicos y pectorales, así como dimensiones más pequeñas para la longitud de la cabeza, longitud predorsal, longitud de la barbilla lateral más larga, longitud del radio dorsal más largo y una menor anchura de la placa dentaria premaxilar; y finalmente, dimensiones mayores en Ictalurus sp. (cuenca del río Culiacán) para distancias como origen de aleta dorsal a la base del último radio anal y origen de aleta dorsal a conexión posterior de aleta adiposa. Los coeficientes estandarizados para las variables canónicas 1 y 2 explicaron el 85.6 y 14.4 % de la variación total, respectivamente. Conclusiones: Los caracteres morfológicos distintivos de Ictalurus sp. de la cuenca del río Culiacán, en combinación con la evidencia mitocondrial conocida para este mismo morfotipo, permite reconocerlo como una unidad evolutivamente significativa y que requiere ser descrita como una especie nueva bajo los protocolos taxonómicos.
Assuntos
Animais , Ictaluridae/classificação , Peixes-Gato/anatomia & histologia , MéxicoRESUMO
Resequencing of Myostatin, Growth Hormone, Follistatin-A-like, Insulin-like Growth Factor I (IGF-I) and Myogenin (MYOG) genes was completed to discover novel genetic variations and assess non synonymous (ns) polymorphisms (SNPs) effect on growth related traits of channel catfish. Wild and farmed animals were used as a discovering population. Resequencing lead to the identification of 59 new variants in the five analyzed genes; 66% found in introns and 34% in coding regions. From coding regions, 14 variants were synonyms and six were ns variations. A mutation rate of one in 129 bp was estimated. Four ns variations were selected for validation and association analysis. In IGF-I two ns polymorphisms, at IGF-I19 the G wild type allele was fixed in population and for IGF-I63 the C allele had a frequency of 0.972 and for mutate allele G of 0.027. In MYOG two ns SNPs were assessed. MYOG131 presented a frequency of alleles T and A, of 0.754 and 0.246, respectively and MYOG233, with a frequency of G and C of 0.775 and 0.225, respectively. Only MYOG131 (g.529T>A) was significantly associated (P < 0.04) to some growth traits. Results suggest MYOG131 g.529T>A as candidate locus for genetic enhancement of growth traits in channel catfish.
Assuntos
Crescimento e Desenvolvimento/genética , Ictaluridae/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Animais , Proteínas Relacionadas à Folistatina/genética , Hormônio do Crescimento/genética , Ictaluridae/crescimento & desenvolvimento , Fator de Crescimento Insulin-Like I/genética , Miogenina/genética , Miostatina/genéticaRESUMO
The acquisition of gut microbes does not occur randomly and is highly dependent on host factors, environmental cues, and self-assembly rules exerted by the microbes themselves. The main objective of this project was to characterize how the gut microbiome develops during the early life stages of Channel Catfish and to identify i) which bacteria are the main constituents of the gut microbiome at different ontogenesis stages, and ii) at which time point(s) the gut microbiome stabilizes. High-throughput Illumina Miseq DNA sequencing of the V4 domain of the 16S rRNA gene was used to assess the microbial community composition during the life stages of Channel Catfish along with water and feed samples. Microbiomes from fertilized eggs, sac fry, swim up fry, pre-fingerlings, and fingerlings were all significantly distinct. OTUs analyses showed that the phylum Proteobacteria, Firmicutes, Fusobacteria and Cyanobacteria dominated the Channel Catfish gut microbiome. During the early stages of ontogenesis, the fish microbiome was dynamic and highly diverse, with significant shifts occurring between fertilized eggs to sac fry (6dph), and from sac fry to swim up fry (15dph). The gut microbiome stabilized between the pre-fingerlings and fingerlings stage (≤90dph) with an observed reduction in species richness. Feed had a more significantly contribution to the microbial colonization of the gut than water. We have identified the period in which the gut microbiome changes rapidly from 15dph until 21dph before stabilizing after 90dph.
Assuntos
Bactérias/classificação , Biodiversidade , Microbioma Gastrointestinal/fisiologia , Ictaluridae/crescimento & desenvolvimento , Ictaluridae/microbiologia , Estágios do Ciclo de Vida/fisiologia , Ração Animal/microbiologia , Animais , Bactérias/genética , Bactérias/isolamento & purificação , DNA Bacteriano/genética , Microbioma Gastrointestinal/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia da ÁguaRESUMO
The objective of this study was to evaluate differential expression of innate and adaptive immune genes, including immunoglobulin, immune cell receptor, cytokine, inflammatory protein, toll-like receptors (TLR) and recombination-activating gene (RAG) in skin from channel catfish, Ictalurus punctatus after immunization with live theronts of Ichthyophthirius multifiliis (Ich) by intraperitoneal injection. The immunized catfish showed significantly higher survival rate (95%) than those of mock-immunized control fish (0% survival) after the theront challenge. The gene expression of innate immune system, such as cytokines (IL-1ß type a, IL-1ß type b, IFN-γ, TGF1-ß and TNF-α) and inflammatory proteins (NF-kB and iNOS 2), showed significant upregulation at day 1 (D1) post-immunization. Expression of TLR genes exhibited a rapid increase from hour 4 (h4) to D10 post-immunization. Genes of the adaptive response, such as the cell receptor MHC I, CD8+ , CD4+ and TCR-α, showed upregulation at D1, D6 and D10. The TCR-ß expression increased rapidly at h4 and remained upregulated until D10. Immunoglobulin IgM upregulation was detected from h4 until D2 while IgD expression was increased from D1 until D10. Rapid upregulation of innate and adaptive immune genes in skin of catfish following live theront vaccination was demonstrated in this study ultimately resulting in significant protection against Ich infection.
Assuntos
Infecções por Cilióforos/veterinária , Doenças dos Peixes/imunologia , Hymenostomatida/imunologia , Ictaluridae/imunologia , Ictaluridae/parasitologia , Pele/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Infecções por Cilióforos/imunologia , Doenças dos Peixes/parasitologia , Imunização/veterinária , Imunoglobulina M , NF-kappa B , Fator de Necrose Tumoral alfaRESUMO
Metabolic adjustments were studied in channel catfish Ictalurus punctatus exposed to 1.5 mg L-1 of phe nol (10% LC50) for four days and recovered for seven days. Lower triacylglycerol (TGA) stores and increased muscle fat free acids (FFA) suggest fat catabolism in muscle. Remarkable liver FFA decrease (-31%) suggests liver fat catabolism as well. Increased muscular ammonia levels and ASAT (aspartate aminotransferase) and decreased plasma aminoacids suggest higher muscular amino acid uptake. Constant levels of glucose and increased liver glycogen stores, associated with lower amino acids in plasma, indicate gluconeogenesis from amino acids. This is supported by higher hepatic ALAT and ASAT. Higher hepatic LDH followed by lower plasma lactate may indicate that plasma lactate was also used as gluconeogenic substrate. Biochemical alterations were exacerbated during the post-exposure recovery period. Reduction in muscle and plasma protein content indicate proteolysis. A higher rate of liver fat catabolism was resulted from a remarkable decrease in hepatic TGA (-58%). Catabolic preference for lipids was observed in order to supply such elevated energy demand. This study is the first insight about the metabolic profile of I. punctatus to cope with phenol plus its ability to recover, bringing attention to the biological consequences of environmental contamination.
Assuntos
Ictaluridae/metabolismo , Fígado/metabolismo , Músculo Esquelético/metabolismo , Fenol/metabolismo , Aminoácidos/metabolismo , Amônia/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Gluconeogênese , Glucose/metabolismo , Ácido Láctico/sangue , Fatores de Tempo , Triglicerídeos/metabolismoRESUMO
The nominal Yaqui catfish, Ictalurus pricei, is a species of Ictaluridae (Siluriformes) often recorded from Northwest Mexico. Southern distribution members of the I. pricei complex in Northwest Mexico include at least one undescribed species that differs from Yaqui catfish in morphological features, herein called "Sinaloa Catfish". Sequencing of four geographical mitogenome haplotypes of Yaqui catfish and Sinaloa catfish showed geographical haplotypes of I. pricei within a clade of specific identity, close to Sinaloa catfish haplotypes. Our molecular phylogeny represents a working hypothesis supporting information on the evolutionary relationships of the Ictalurus species from Western Mexico and Western USA.
Assuntos
Peixes-Gato/genética , Genoma Mitocondrial/genética , Ictaluridae/genética , Animais , Haplótipos/genética , México , FilogeniaRESUMO
Se quizo evaluar las características morfológicas y morfométricas anatómicas del aparato digestivo del bagre de canal, su correlación con los hábitos alimenticios. Utilizamos 19 ejemplares de bagre de canal sano con un peso promedio de 522,77 ± 60,87 gramos. Después de capturar y 24 horas de ayuno, los animales se sacrificaron por anestesia con benzocaína a una concentración de 50mg/kg procedieron sección transversal de la médula espinal. Llevamos a cabo revisiones morfológicas y topográficas de la cavidad orofaríngea, tubo digestivo y glândulas accesorias. Presencia observada de fisura oral rostral, cuatro pares de barbillas, dientes oral y faríngea, el esófago con el gran número de pliegues longitudinales, estómago desarrollado y mucosa altamente plegada, se presentaron varios convulaciones en el intestino medio . En cuanto a la morfometría, se determinó la longitud estándar del cuerpo, longitud intestinal , cociente intestinal, índice hepatosomático y el índice digestivo somático. No hubo diferencia significativa en el cociente intestinal, sin embargo, se observó que los otros parámetros morfométricos fueron mayores en las hembras. La morfología del sistema digestivo no se observaron diferencias entre los géneros. Cabe mencionar que el bagre de canal presenta características morfológicas y morfométricas en consonancia con los de los omnívoros con tendencia piscívoras. Sin embargo, el estudio puede indicar que esta especie esun período de adaptación a un nuevo hábito de alimentos, debido a algún tipo de presión ambiental
Longed to evaluate macroscopic and morphology characteristics of channel catfishs digestive system correlating them with feeding habit. Were used 26 specimens of healthy channel catfish, with an average weight of 606 grams. After capture and 24 hours of fasting, the animals were euthanized through anesthesia containing benzocaine in concentration of 50mg/kg followed by spinal cord transverse section. Morphologic and topographic evaluations of buccopharyngeal cavity, feeding canal and accessory glands were carried out. Presence of wide oral cleft, oral and pharyngeal teeth, esophagus with a large number of longitudinal folds, developed stomach with highly folded mucosa were observed, several convolutions were noted at the posterior intestine. As for morphometry, standard and intestinal lengths were determined and the Intestine Relative Length (IRL) was calculated. There were no significative differences of average IRL between the groups. It can be mentioned that channel catfish has morphologic and morphometric characteristics that are compatible to the ones of other omnivorous fishes with piscivorous tendency. Nevertheless, this study may indicate that this specie is under adaptation period to a new feeding habit, due to some sort of environment pressure
Almejou-se avaliar as características morfológica e morfométrica do sistema digestório do bagre de canal, correlacionando-as ao hábito alimentar. Utilizaram-se 19 exemplares de bagre de canal hígidos (12 machos e 7 fêmeas), com peso médio de 522,77 ± 60,87 gramas. Após captura e jejum de 24 horas, os animais foram eutanasiados mediante anestesia com benzocaina na concentração de 50mg/L prosseguido de secção transversal da medula espinhal. Efetuaram-se avaliações morfológica e topográfica da cavidade bucofaríngea, do canal alimentar e das glândulas anexas. Observaram-se presença de fenda bucal rostral, quatro pares de barbilhões, dentes orais e faringianos, esôfago com grande número de pregas longitudinais, estômago desenvolvido e com mucosa altamente pregueada, e evidenciaram-se várias convulações no intestino médio. Quanto à morfometria, determinaram-se os comprimentos corpóreo padrão, comprimento intestinal, quociente intestinal, índice hepatosomático e índice digestivo somático. Não houve diferença significativa do quociente intestinal, contudo, observou-se que os demais parâmetros morfométricos foram maiores nas fêmeas. Quanto à morfologia não se observaram diferenças do sistema digestório entre os gêneros. Pode-se mencionar que o bagre de canal apresenta características morfológicas e morfométricas compatíveis aos de peixes onívoros com tendência piscívora. Não obstante, o estudo pode indicar que esta espécie possa estar em período de adaptação a um novo hábito alimentar, em decorrência a algum tipo de pressão ambiental
Assuntos
Animais , Ictaluridae/anatomia & histologia , Ictaluridae/fisiologia , Sistema Digestório/anatomia & histologia , Animais Domésticos/anatomia & histologia , Comportamento Alimentar , Peixes/anatomia & histologiaRESUMO
Se quizo evaluar las características morfológicas y morfométricas anatómicas del aparato digestivo del bagre de canal, su correlación con los hábitos alimenticios. Utilizamos 19 ejemplares de bagre de canal sano con un peso promedio de 522,77 ± 60,87 gramos. Después de capturar y 24 horas de ayuno, los animales se sacrificaron por anestesia con benzocaína a una concentración de 50mg/kg procedieron sección transversal de la médula espinal. Llevamos a cabo revisiones morfológicas y topográficas de la cavidad orofaríngea, tubo digestivo y glândulas accesorias. Presencia observada de fisura oral rostral, cuatro pares de barbillas, dientes oral y faríngea, el esófago con el gran número de pliegues longitudinales, estómago desarrollado y mucosa altamente plegada, se presentaron varios convulaciones en el intestino medio . En cuanto a la morfometría, se determinó la longitud estándar del cuerpo, longitud intestinal , cociente intestinal, índice hepatosomático y el índice digestivo somático. No hubo diferencia significativa en el cociente intestinal, sin embargo, se observó que los otros parámetros morfométricos fueron mayores en las hembras. La morfología del sistema digestivo no se observaron diferencias entre los géneros. Cabe mencionar que el bagre de canal presenta características morfológicas y morfométricas en consonancia con los de los omnívoros con tendencia piscívoras. Sin embargo, el estudio puede indicar que esta especie esun período de adaptación a un nuevo hábito de alimentos, debido a algún tipo de presión ambiental(AU)
Longed to evaluate macroscopic and morphology characteristics of channel catfishs digestive system correlating them with feeding habit. Were used 26 specimens of healthy channel catfish, with an average weight of 606 grams. After capture and 24 hours of fasting, the animals were euthanized through anesthesia containing benzocaine in concentration of 50mg/kg followed by spinal cord transverse section. Morphologic and topographic evaluations of buccopharyngeal cavity, feeding canal and accessory glands were carried out. Presence of wide oral cleft, oral and pharyngeal teeth, esophagus with a large number of longitudinal folds, developed stomach with highly folded mucosa were observed, several convolutions were noted at the posterior intestine. As for morphometry, standard and intestinal lengths were determined and the Intestine Relative Length (IRL) was calculated. There were no significative differences of average IRL between the groups. It can be mentioned that channel catfish has morphologic and morphometric characteristics that are compatible to the ones of other omnivorous fishes with piscivorous tendency. Nevertheless, this study may indicate that this specie is under adaptation period to a new feeding habit, due to some sort of environment pressure(AU)
Almejou-se avaliar as características morfológica e morfométrica do sistema digestório do bagre de canal, correlacionando-as ao hábito alimentar. Utilizaram-se 19 exemplares de bagre de canal hígidos (12 machos e 7 fêmeas), com peso médio de 522,77 ± 60,87 gramas. Após captura e jejum de 24 horas, os animais foram eutanasiados mediante anestesia com benzocaina na concentração de 50mg/L prosseguido de secção transversal da medula espinhal. Efetuaram-se avaliações morfológica e topográfica da cavidade bucofaríngea, do canal alimentar e das glândulas anexas. Observaram-se presença de fenda bucal rostral, quatro pares de barbilhões, dentes orais e faringianos, esôfago com grande número de pregas longitudinais, estômago desenvolvido e com mucosa altamente pregueada, e evidenciaram-se várias convulações no intestino médio. Quanto à morfometria, determinaram-se os comprimentos corpóreo padrão, comprimento intestinal, quociente intestinal, índice hepatosomático e índice digestivo somático. Não houve diferença significativa do quociente intestinal, contudo, observou-se que os demais parâmetros morfométricos foram maiores nas fêmeas. Quanto à morfologia não se observaram diferenças do sistema digestório entre os gêneros. Pode-se mencionar que o bagre de canal apresenta características morfológicas e morfométricas compatíveis aos de peixes onívoros com tendência piscívora. Não obstante, o estudo pode indicar que esta espécie possa estar em período de adaptação a um novo hábito alimentar, em decorrência a algum tipo de pressão ambiental(AU)
Assuntos
Animais , Ictaluridae/anatomia & histologia , Ictaluridae/fisiologia , Sistema Digestório/anatomia & histologia , Peixes/anatomia & histologia , Animais Domésticos/anatomia & histologia , Comportamento AlimentarRESUMO
A time-course feeding trial was conducted for 120 days on juvenile channel catfish (Ictalurus punctatus) to study the effects of diets differing in oil source (fish oil or soy oil) and supplementation with a commercial probiotic. Relative levels of Δ6-fatty acid desaturase (Δ6-FAD) and fatty acid elongase (FAE) expression were assessed in brain and liver tissues. Both genes showed similar expression levels in all groups studied. Fish weight-to-length relationships were evaluated using polynomial regression analyses, which identified a burst in weight and length in the channel catfish on day 105 of treatment; this increase was related to an increase in gene expression. Mid-intestinal lactic acid bacterium (LAB) count was determined according to morphological and biochemical criteria using API strips. There was no indication that intestinal LAB count was affected by the modified diets. The Cunningham glass adherence method was applied to evaluate phagocytic cell activity in peripheral blood. Reactive oxygen species (ROS) generation was assessed through the respiratory burst activity of spleen macrophages by the NBT reduction test. Probiotic-supplemented diets provided a good substrate for innate immune system function; the phagocytic index was significantly enhanced in fish fed soy oil and the probiotic, and at the end of the experimental period, ROS production increased in fish fed soy oil. The substitution of fish oil by soy oil is recommended for food formulation and will contribute to promoting sustainable aquaculture. Probiotics are also recommended for channel catfish farming as they may act as immunonutrients.
Assuntos
Acetiltransferases/metabolismo , Proteínas de Peixes/metabolismo , Ictaluridae/metabolismo , Linoleoil-CoA Desaturase/metabolismo , Acetiltransferases/genética , Ração Animal , Animais , Aquicultura , Peso Corporal , Encéfalo/enzimologia , Dieta , Elongases de Ácidos Graxos , Proteínas de Peixes/genética , Microbioma Gastrointestinal , Expressão Gênica , Ictaluridae/genética , Ictaluridae/crescimento & desenvolvimento , Linoleoil-CoA Desaturase/genética , Fígado/enzimologia , Macrófagos/fisiologia , Fagocitose , Probióticos/administração & dosagem , Explosão Respiratória , Óleo de Soja/administração & dosagemRESUMO
We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus) fish species were offered as prey to P. corruscans in 300 L aquaria with three habitat complexity treatments (0%, 50% and 100% structure-covered). Prey survival was variable through time and among species (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), depending largely on species-specific prey behavior but also on prey size and morphological defenses. Habitat complexity did not directly affect P. corruscans piscivory but some prey species changed their microhabitat use and shoaling behavior among habitat treatments in predator's presence. Pseudoplatystoma corruscans preyed preferentially on smaller individuals of those invasive species with weak morphological defensive features that persisted in a non-shoaling behavior. Overall, our results contrast with those in a companion experiment using a diurnal predator, suggesting that nocturnal piscivores preferentially prey on different (rather diurnal) fish species and are less affected by habitat complexity. Our findings suggest that recovering the native populations of P. corruscans might help controling some fish species introduced to the Paraná River basin, particularly C. piquiti and O. niloticus, whose parental care is expected to be weak or null at night.(AU)
A relação predador-presa entre juvenis de pintado Pseudoplatystoma corruscans (piscívoro nativo) e jovens do ano de espécies nativas e invasoras de peixes da bacia do rio Paraná, Brasil, foi testada experimentalmente. Três espécies de peixe invasoras (o tucunaré Cichla piquiti, a tilápia do Nilo Oreochromis niloticus e o bagre do canal Ictalurus punctatus) e duas nativas (o lambari do rabo amarelo Astyanax altiparanae e o curimbatá Prochilodus lineatus) foram oferecidas como presa para P. corruscans em microcosmos, com três tratamentos de complexidade de habitat (0%, 50% e 100% de cobertura por estruturas submersas). A sobrevivência de presas variou ao longo do tempo e entre espécies (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), sendo governada, em grande parte, por diferenças espécies-específicas no comportamento das presas, mas também pelo tamanho e defesas morfológicas das mesmas. A complexidade de habitat não afetou diretamente a piscivoria de P. corruscans, mas, na presença do predador, algumas espécies-presa alteraram seu comportamento quanto ao uso de micro-habitat e grau de agregação entre os níveis de complexidade de habitat. Pseudoplatystoma corruscans predou preferencialmente sobre os indivíduos menores das espécies invasoras que apresentaram estruturas morfológicas defensivas pouco desenvolvidas e que não formavam cardume. Em geral, os resultados obtidos contrastam com os de um experimento análogo, no qual foi usado um piscívoro diurno, sugerindo que piscívoros noturnos predam preferencialmente sobre espécies de peixes diferentes (de hábitos mais diurnos) e que são menos afetados pela complexidade estrutural de habitats. Os resultados obtidos sugerem que a recuperação de populações nativas de P. corruscans poderia contribuir para o controle de algumas espécies de peixes introduzidas no rio Paraná, especialmente C. piquiti e O. niloticus, dos quais se espera que o cuidado parental seja reduzido ou nulo à noite.(AU)
Assuntos
Animais , Caça/etnologia , Ecossistema/análise , Comportamento Predatório/fisiologia , Peixes-Gato/crescimento & desenvolvimento , Espécies Introduzidas , Adaptação Psicológica/fisiologia , Ciclídeos/crescimento & desenvolvimento , Ictaluridae/crescimento & desenvolvimentoRESUMO
We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus) fish species were offered as prey to P. corruscans in 300 L aquaria with three habitat complexity treatments (0%, 50% and 100% structure-covered). Prey survival was variable through time and among species (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), depending largely on species-specific prey behavior but also on prey size and morphological defenses. Habitat complexity did not directly affect P. corruscans piscivory but some prey species changed their microhabitat use and shoaling behavior among habitat treatments in predator's presence. Pseudoplatystoma corruscans preyed preferentially on smaller individuals of those invasive species with weak morphological defensive features that persisted in a non-shoaling behavior. Overall, our results contrast with those in a companion experiment using a diurnal predator, suggesting that nocturnal piscivores preferentially prey on different (rather diurnal) fish species and are less affected by habitat complexity. Our findings suggest that recovering the native populations of P. corruscans might help controling some fish species introduced to the Paraná River basin, particularly C. piquiti and O. niloticus, whose parental care is expected to be weak or null at night.
A relação predador-presa entre juvenis de pintado Pseudoplatystoma corruscans (piscívoro nativo) e jovens do ano de espécies nativas e invasoras de peixes da bacia do rio Paraná, Brasil, foi testada experimentalmente. Três espécies de peixe invasoras (o tucunaré Cichla piquiti, a tilápia do Nilo Oreochromis niloticus e o bagre do canal Ictalurus punctatus) e duas nativas (o lambari do rabo amarelo Astyanax altiparanae e o curimbatá Prochilodus lineatus) foram oferecidas como presa para P. corruscans em microcosmos, com três tratamentos de complexidade de habitat (0%, 50% e 100% de cobertura por estruturas submersas). A sobrevivência de presas variou ao longo do tempo e entre espécies (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), sendo governada, em grande parte, por diferenças espécies-específicas no comportamento das presas, mas também pelo tamanho e defesas morfológicas das mesmas. A complexidade de habitat não afetou diretamente a piscivoria de P. corruscans, mas, na presença do predador, algumas espécies-presa alteraram seu comportamento quanto ao uso de micro-habitat e grau de agregação entre os níveis de complexidade de habitat. Pseudoplatystoma corruscans predou preferencialmente sobre os indivíduos menores das espécies invasoras que apresentaram estruturas morfológicas defensivas pouco desenvolvidas e que não formavam cardume. Em geral, os resultados obtidos contrastam com os de um experimento análogo, no qual foi usado um piscívoro diurno, sugerindo que piscívoros noturnos predam preferencialmente sobre espécies de peixes diferentes (de hábitos mais diurnos) e que são menos afetados pela complexidade estrutural de habitats. Os resultados obtidos sugerem que a recuperação de populações nativas de P. corruscans poderia contribuir para o controle de algumas espécies de peixes introduzidas no rio Paraná, especialmente C. piquiti e O. niloticus, dos quais se espera que o cuidado parental seja reduzido ou nulo à noite.
Assuntos
Animais , Caça/etnologia , Comportamento Predatório/fisiologia , Ecossistema/análise , Espécies Introduzidas , Peixes-Gato/crescimento & desenvolvimento , Adaptação Psicológica/fisiologia , Ciclídeos , Ictaluridae/crescimento & desenvolvimentoRESUMO
This study evaluated the influence of temperature on the immune responses and hematological parameters in channel catfish Ictalurus punctatus immunized via intraperitoneal injection with live theronts of Ichthyophthirius multifiliis. Fish were distributed in 18 aquaria and received 9 treatments: 4 groups of fish were vaccinated with live theronts and maintained at constant temperature 15 °C, 20 °C, 25 °C and 30 °C; 3 groups of fish vaccinated and subjected to cycling temperature regime from 15-25 °C, 20-25 °C and 20-30 °C, changed 5 °C each day; 2 groups of fish were not vaccinated and served as controls at 25 °C, one with Ich challenge and the other without challenge. Non vaccinated fish and those vaccinated at 15 °C or 15-25 °C did not show anti-Ich antibodies in the serum 14 and 21 days post-immunization. The antibody levels were significantly higher from fish vaccinated at 25 °C, 30 °C, 20-25 °C and 20-30 °C compared to fish at 15 °C, 20 °C and 15-25 °C both 14 and 21 days post-immunization. At constant water temperature, fish vaccinated at 15 °C showed significantly higher mortality rate (67.8%, P < 0.05) than those vaccinated at 20 °C, 25 °C, and 30 °C (0-10.7% mortalities). At cycling water temperature, fish vaccinated at 15-25 °C showed significantly higher mortality rate (67.8%) than those vaccinated at 20-25 °C and 20-30 °C (P < 0.05). Twenty days after immunization fish vaccinated at 30 °C and 20-30 °C showed significant increase in the red blood cells, white blood cells, thrombocytes and monocytes. Six days after challenge with I. multifiliis theronts the fish showed decreased white blood cells, thrombocytes and monocytes. This study suggests that vaccinated catfish were severely impacted by low temperature, either at 15 °C constant temperature or at 15-25 °C cycling temperature. The fish showed no anti-Ich antibodies and suffered high mortality similar to non vaccinated control fish.
Assuntos
Anticorpos Antiprotozoários/imunologia , Infecções por Cilióforos/veterinária , Doenças dos Peixes/imunologia , Doenças dos Peixes/parasitologia , Hymenostomatida/imunologia , Ictaluridae , Temperatura , Animais , Anticorpos Antiprotozoários/sangue , Aquicultura , Contagem de Células Sanguíneas/veterinária , Infecções por Cilióforos/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Injeções Intraperitoneais/veterinária , Modelos Lineares , Fatores de Tempo , Vacinação/veterináriaRESUMO
This study characterises morphologically Trichodina heterodentata Duncan, 1977 from channel catfish, Ictalurus punctatus (Rafinesque, 1818) in the State of Santa Catarina, Brazil. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with Giemsa. Ten characteristics were selected to compare the present material with other morphological characterisations of T. heterodentata. Prevalence rate was 100%, mean intensity 89,333.70 (3,125 to 299,100 parasites per host). Trichodina heterodentata was considered medium-sized trichodinid with mean body diameter 59.4 +/- 8.5 microm, denticulate ring 38.5 +/- 4.5 microm, adhesive disc 60.2 +/- 6.7 microm diameter and 24.4 +/- 1.6 denticles. In relation to previous reports of T. heterodentata this material resembles in 90% of the analysed characters. This work confirms the biometrical variation that exists in the different populations of T. heterodentata. A list of hosts and comparative measurements of T. heterodentata are presented and the channel catfish is considered a new host.
Assuntos
Infecções por Cilióforos/epidemiologia , Doenças dos Peixes/parasitologia , Ictaluridae/parasitologia , Oligoimenóforos/classificação , Oligoimenóforos/isolamento & purificação , Animais , Brasil/epidemiologia , Doenças dos Peixes/epidemiologia , PrevalênciaRESUMO
This study characterises morphologically Trichodina heterodentata Duncan, 1977 from channel catfish, Ictalurus punctatus (Rafinesque, 1818) in the State of Santa Catarina, Brazil. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with Giemsa. Ten characteristics were selected to compare the present material with other morphological characterisations of T. heterodentata. Prevalence rate was 100 percent, mean intensity 89,333.70 (3,125 to 299,100 parasites per host). Trichodina heterodentata was considered medium-sized trichodinid with mean body diameter 59.4 ± 8.5 μm, denticulate ring 38.5 ± 4.5 μm, adhesive disc 60.2 ± 6.7 μm diameter and 24.4 ± 1.6 denticles. In relation to previous reports of T. heterodentata this material resembles in 90 percent of the analysed characters. This work confirms the biometrical variation that exists in the different populations of T. heterodentata. A list of hosts and comparative measurements of T. heterodentata are presented and the channel catfish is considered a new host.
Este estudo caracteriza morfologicamente Trichodina heterodentata Duncan, 1977 em bagre-do-canal, Ictalurus punctatus (Rafinesque, 1818) no Estado de Santa Catarina, Brasil. Esfregaços do corpo e brânquias foram secados à temperatura ambiente, impregnados com nitrato de Prata e/ou corados com Giemsa. Dez características foram selecionadas para comparar o presente material com as diferentes caracterizações morfológicas de T. heterodentata. A taxa de prevalência foi de 100 por cento, a intensidade média foi de 89.333.75 (3.125 a 299.100 parasitos por hospedeiro). Trichodina heterodentata foi considerado um tricodinídeo de tamanho médio com a média do diâmetro do corpo de 59,4 ± 8.5 μm, anel denticulado 38,5 ± 4,5 μm, disco adesivo 60,2 ± 6,7 μm de diâmetro e 24,4 ± 1,6 dentículos. Em relação a registros prévios de T. heterodentata, 90 por cento das características foram semelhantes. Este trabalho confirma a variação biométrica que existe em diferentes populações de T. heterodentata. Uma lista de hospedeiros e medidas comparativas de T. heterodentata são apresentadas e o bagre-do-canal considerado um novo hospedeiro.
Assuntos
Animais , Infecções por Cilióforos/epidemiologia , Doenças dos Peixes/parasitologia , Ictaluridae/parasitologia , Oligoimenóforos/classificação , Oligoimenóforos/isolamento & purificação , Brasil/epidemiologia , Doenças dos Peixes/epidemiologia , PrevalênciaRESUMO
This study characterises morphologically Trichodina heterodentata Duncan, 1977 from channel catfish, Ictalurus punctatus (Rafinesque, 1818) in the State of Santa Catarina, Brazil. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with Giemsa. Ten characteristics were selected to compare the present material with other morphological characterisations of T. heterodentata. Prevalence rate was 100 percent, mean intensity 89,333.70 (3,125 to 299,100 parasites per host). Trichodina heterodentata was considered medium-sized trichodinid with mean body diameter 59.4 ± 8.5 μm, denticulate ring 38.5 ± 4.5 μm, adhesive disc 60.2 ± 6.7 μm diameter and 24.4 ± 1.6 denticles. In relation to previous reports of T. heterodentata this material resembles in 90 percent of the analysed characters. This work confirms the biometrical variation that exists in the different populations of T. heterodentata. A list of hosts and comparative measurements of T. heterodentata are presented and the channel catfish is considered a new host.(AU)
Este estudo caracteriza morfologicamente Trichodina heterodentata Duncan, 1977 em bagre-do-canal, Ictalurus punctatus (Rafinesque, 1818) no Estado de Santa Catarina, Brasil. Esfregaços do corpo e brânquias foram secados à temperatura ambiente, impregnados com nitrato de Prata e/ou corados com Giemsa. Dez características foram selecionadas para comparar o presente material com as diferentes caracterizações morfológicas de T. heterodentata. A taxa de prevalência foi de 100 por cento, a intensidade média foi de 89.333.75 (3.125 a 299.100 parasitos por hospedeiro). Trichodina heterodentata foi considerado um tricodinídeo de tamanho médio com a média do diâmetro do corpo de 59,4 ± 8.5 μm, anel denticulado 38,5 ± 4,5 μm, disco adesivo 60,2 ± 6,7 μm de diâmetro e 24,4 ± 1,6 dentículos. Em relação a registros prévios de T. heterodentata, 90 por cento das características foram semelhantes. Este trabalho confirma a variação biométrica que existe em diferentes populações de T. heterodentata. Uma lista de hospedeiros e medidas comparativas de T. heterodentata são apresentadas e o bagre-do-canal considerado um novo hospedeiro.(AU)
Assuntos
Animais , Cilióforos/parasitologia , Ectoparasitoses/prevenção & controle , Ictaluridae/parasitologia , Classificação/métodos , Biometria/instrumentaçãoRESUMO
Liver microsomes from market-size (n = 6) rainbow trout, channel catfish and tilapia were used to investigate in vitro biotransformation kinetics of albendazole (ABZ). ABZ was transformed to a single metabolite, ABZ sulfoxide (ABZ-SO). Catfish displayed the highest maximal velocity (V(max) = 264.0 +/- 58.6 pmols ABZ-SO/min/mg protein) followed by tilapia (112.3 +/- 8.2) and rainbow trout (73.3 +/- 10.3). V(max) in catfish was significantly different (P < 0.05) from the other two species. Michaelis-Menten constant (K(m)) values (microm) varied significantly among the species: rainbow trout (3.9 +/- 0.5), tilapia (9.2 +/- 1.7) and catfish (22.0 +/- 3.2). However, V(max)/K(m) ratios showed no difference among the three species, making them equally efficient performing this phase I biotransformation reaction. In a second series of experiments, channel catfish (n = 6 per treatment) were dosed in vivo with gel-food containing ABZ (10 mg/kg, p.o.). Fish were killed at 24, 48, 72 and 120 h after dosage. Control fish were fed ABZ-free feed. Induction of ethoxyresorufin-o-deethylase activity was significant (P < 0.05) in all ABZ-dosed treatments as compared with controls.