Silver Catfish Research Articles

Efeitos de dietas contendo concentrados proteicos vegetais no desempenho e atividade de enzimas digestivas de jundiá (Rhamdia quelen)

The purpose of study was to evaluate the effect of using protein concentrates crambe and sunflower meal in the diet of silver catfish juveniles, as substitute for animal protein source. A total of 300 silver catfish had been separate in 15 experimental units of 280 L, totaling five treatments with three replications. We evaluated two levels (25% and 50%) replacement of the meat and bone meal by protein concentrates of crambe and sunflower meals. Evaluated growth parameters, biological index and digestive enzymes in fish. There was no statistical difference for mass (g) and standard length (cm), but the fish diet CPFCr-25% had greater total length (cm). No difference in dry matter, crude protein and total protein deposited (calculated). However, there was a higher concentration of ash in the carcass of the animals fed the control diet and CPFCr-50% in relation to diet CPFG- 50%, in addition, higher levels of lipids in fish fed diet CPFG-50%. No significant differences for hepatosomatic index, digestive somatic index and intestinal quotient of animals subjected to different treatments. The activity of digestive enzymes trypsin and chymotrypsin did not change. There was increased activity of acid protease. The quantitative and qualitative increase in protein concentration from this fraction allows the use of bran protein concentrates crambe and sunflower as substitutes for animal protein source.

Using the essential oil of Aloysia triphylla (L'Her.) Britton to sedate silver catfish (Rhamdia quelen) during transport improved the chemical and sensory qualities of the fish during storage in ice.

Exposure of silver catfish to 40 μL/L of the essential oil of Aloysia triphylla (AT) during in vivo transport delayed the onset and resolution of rigor mortis as well as the degradation of IMP into HxR compared to the control. The fish that were treated with 30 or 40 μL/L of AT received lower sensory demerit scores after 10 d of storage in ice compared to the control, and the fish that were treated with 40 μL/L of AT had a longer sensory shelf life than did the control. These results indicated that using AT as a sedative in the water in which the silver catfish were transported extended their freshness and increased their shelf life during refrigerated storage. Interest in natural anesthetics, such as Aloysia triphylla, has increased in the field of commercial aquaculture because they reduce the number of fish lesions acquired during capture, handling, and transportation. Fish sedated with the essential oil of A. triphylla at 40 μL/L during transport before slaughter exhibited a delay in the loss of freshness and an increased shelf life in ice. In addition to improving animal welfare before slaughter, the essential oil appears to be a promising product for improving fish conservation in the food industry.

Farelo de crambe nas formas in natura ou reduzida em antinutrientes na dieta do jundiá

Este estudo avaliou os efeitos da substituição parcial de farinha de peixe e farinha de carne e ossos por farelo de crambe, sobre o crescimento, enzimas digestivas e parâmetros bioquímicos no jundiá (Rhamdia quelen). Este coproduto agroindustrial foi incluído na alimentação de jundiás na forma in natura ou reduzido em antinutrientes, obtido após a aplicação de tratamento químico ao farelo. A inclusão desses ingredientes foi comparada ao tratamento controle (proteína baseada em farinhas de origem animal) durante nove semanas. Crescimento semelhante ao controle foi observado em peixes alimentados com farelo de crambe in natura ou tratado quimicamente na dieta. A inclusão do farelo in natura reduziu a atividade de protease ácida e colesterol plasmático, mas não alterou os parâmetros bioquímicos hepáticos. Menor concentração de glicogênio e glicose no fígado e aumento na aspartato aminotransferase foi encontrada nos peixes alimentados com farelo de crambe tratado, sinalizando uma condição de carência energética. A similar resposta no crescimento, aliada às leves alterações digestivas e metabólicas com o farelo de crambe in natura em relação ao farelo tratado, pode indicar que, no nível de inclusão utilizado, este ingrediente não necessita de um processo prévio para redução de antinutrientes.

Exposure to Sublethal Concentrations of Copper Changes Biochemistry Parameters in Silver Catfish, Rhamdia quelen, Quoy & Gaimard

The effects of Cu exposure on catalase (CAT) and acetylcholinesterase (AChE) activity, formation of thiobarbituric acid-reactive species (TBARS) and metabolic parameters were evaluated in silver catfish (Rhamdia quelen). The fish were exposed for 45 days to 0, 16 and 29 μg/L Cu. The fish that were exposed to Cu exhibited lower TBARS levels in the muscle and higher TBARS levels in the liver. They also showed lower CAT activity in the liver and lower AChE activity in the brain and muscle. Higher glucose and lactate and lower protein plasma levels were observed in the fish exposed to Cu. The changes in the hepatic metabolic parameters were Cu concentration dependent. In the muscle, lower glycogen and higher lactate levels were observed in the fish exposed to Cu. Alterations in the metabolic parameters showed a preference for the anaerobic pathway of energy production and liver protein catabolism to supply the energy demand.

Humic acid and moderate hypoxia alter oxidative and physiological parameters in different tissues of silver catfish (Rhamdia quelen)

Aquatic animals are naturally exposed simultaneously to environments with different concentrations of humic acid (HA) and seasonal or daily variations of dissolved oxygen (DO) levels. This study investigated the effects of simultaneous exposure to different HA and DO levels on plasma ion levels and some hematological and oxidative parameters in different tissues of silver catfish (Rhamdia quelen). The fish were exposed to 0, 2.5 or 5mgL(-1) HA for 120h. After this period, each group was divided into two groups: normoxia and hypoxia. Exposure to the different DO levels lasted 96h, totaling 216h of experimentation. At the end of the experimental period, blood sampling was performed, and the fish were euthanized prior to the excision of the gills and the brain to evaluate hematological and oxidative parameters. To verify the antioxidant capacity of HA, total phenolic compounds were measured. In general, all tissues of silver catfish exposed simultaneously to hypoxia and different HA concentrations showed a reduction in lipid peroxidation levels, as well as a modulation of the antioxidant system. These effects occurred in an HA concentration-dependent manner. Thus, HA is beneficial to silver catfish exposed to hypoxia. These beneficial effects can be attributed, most likely, to the action of the different HA constituents and functional groups, including phenolic compounds, which have antioxidant properties.

Digestible energy of crude glycerol for pacu and silver catfish

The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus) is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen) is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs) for energy of crude glycerol for P. mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg-1 of digestible energy for Pacu and Silver catfish, respectively. In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.

Genetic Diversity of Selected Commercial Freshwater Fishes Based On Phospholipase C Zeta (Plc) Expression

Egg activation is important to help release the egg from meiotic arrest and blockpolyspermy. It is linked with an increase in intracellular egg calcium ions (Ca 2+ ) in almost all species studied and current studies imply that the mammalian sperm factor involved is a sperm-specific phospholipase C zeta, PLC ζ. Here, we report the identification of PLCζ in the testis and egg of LampamJawa. Our findings provide the evidence that PLCζ is present in the species of male and female LampamJawa (Barbonymusgonionotus). For this study, six types of commercial freshwater fish were selected i.e. Red Tilapia (Oreochromis sp. Red Tilapia), Black Tilapia (Oreochromismossambicus), Catfish or Keli (Ictaluruspunctatus), Silver Catfish or Patin (Pangasiuspangasius), Snakehead Fish or Haruan (Channastriatus) and Silver Barb or LampamJawa (Barbonymusgonionotus). The objectives of this study were to isolate the mRNA from the gonads of freshwater fishes, to identify and amplify the phospholipase C zeta (PLCζ) gene fragments, to sequence the purified DNA fragments and to compare the PLCζ sequence to other PLCζ sequence available in NCBI database. For the study of PLCζ expression, male and female LampamJawa showed bands at around 420bp in agarose gel electrophoresis suggesting the presence of PLCζ gene while no significant bands were found in other types of fishes used in this study.

Bioaccumulation of Heavy Metals in Fish Sourced from Environmentally Stressed Axis of River Niger: Threat to Ecosystem and Public Health

Pollution of freshwater ecosystems is alarmingly becoming high in Nigeria with attendant public health effects on the dependent populations. Fish, a source of protein with pronounced placement on local food menu is now considered an important dietary threat of heavy metal toxicity via consumptions. Bioaccumulation of heavy metals (copper, zinc and lead) in Silver catfish (Schilbe intermedius) from River Niger was conducted. The Fish samples were collected from different sites of Onitsha axis of the River Niger owing to their environmental stresses. Samples were analyzed for heavy metal (copper- Cu, zinc- Zn, and lead- Pb) concentrations in muscle tissues using the Atomic Absorption Spectrophotometer (AAS) and compared with Food and Agriculture Organization safe limits. Margin of exposure (MOE) was estimated to measure the potential public health risk of consuming the contaminated fish. The concentrations of heavy metals (Cu- 8.92±4.748, Zn- 0.36±0.249, and Pb- 2.689±1.505) observed were significant (P Pb>Zn. Statistical Pearson moment correlation analysis showed that the concentrations of heavy metals detected were independent of the weight of sampled fish for zinc but was positively correlated for copper and lead. Relating the mean metal concentrations obtained in the study with Food and Agriculture Organization standard for fish muscles indicated that mean concentrations of copper, zinc and lead are far above safe margins for human consumption except the fish sourced from sites A4 and A9 for lead and zinc, respectively. Margin of exposure was below one and tentatively considered not to be of risk to public health. However, there is considerable contamination of the Silver catfish from the River Niger with heavy metals. It is recommended that substantial attention be paid to the heavy metal levels in freshwater fishes from the river. Measures should be put in place to regulate the indiscriminate dredging activities, discharge of raw sewage and industrial effluent into the river and regular public health check on the level of heavy metals among the populace in the communities that border the area should be employed.

Hematological and histopathological changes in silver catfish Rhamdia quelen (Siluriformes) exposed to clomazone herbicide in the Madre River, Santa Catarina State, Southern Brazil

This study evaluated the influence of the clomazone herbicide (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) contamination on the hematological parameters and histological changes in gills and liver of silver catfish (Rhamdia quelen) from Madre River, Santa Catarina State, Southern Brazil. Fish were collected between March 2010 and January 2012 at two different sites of the Madre River, one site receiving residual water (contaminated site) from rice culture (n = 49) and another that do not receive residual water (reference site) (n = 48). The herbicide clomazone analysis detected 3.40 ± 1.70 μg/L in the contaminated site and 1.1 ± 0.33 μg/L in the reference site. Fish from contaminated site showed increased (P < 0.05) number of monocytes suggesting the possible defense response as a result of chronic exposure to clomazone. On the other hand, no difference was found in the hematocrit percentage, red blood cell count, total thrombocyte number, white blood cell count, lymphocytes, and neutrophils number. Fish from both sites showed histopathological changes in gills and liver, possibly caused by chronic exposure to contamination. The influence of herbicide sub doses on fish health is also discussed.

The use of eugenol against Aeromonas hydrophila and its effect on hematological and immunological parameters in silver catfish (Rhamdia quelen)

The aim of this study was to evaluate the activity of eugenol against the fish pathogen Aeromonas hydrophila and eugenol's effect on hematological and natural immune parameters in silver catfish (Rhamdia quelen). In vitro, eugenol showed weak activity against A. hydrophila, but in vivo, at a subinhibitory concentration (10mgL−1), it promoted survival in infected silver catfish. Eugenol (50μgmL−1) reduced the hemolytic activity of A. hydrophila supernatant in vitro in fish erythrocytes. Subjecting catfish to eugenol baths (5 and 10mgL−1) for five days did not alter the hematological and immunological parameters studied in this work. Based on these results, eugenol can be used to treat or prevent bacterial diseases in fish.

Alterations in carbohydrate and protein metabolism in silver catfish (Rhamdia quelen) exposed to cadmium

Changes in carbohydrate and protein metabolism were studied in silver catfish Rhamdia quelen exposed to cadmium (0; 0.236 or 0.414mg/L) during 7 and 14 days. After exposure time the fish were exposed to recovery period (water without cadmium), during 7 and 14 days. Different alterations in the metabolic parameters were observed such as an increase in lactate, protein, amino acid and ammonia levels as well as a reduction in glucose values after the exposure periods in liver. In muscle, glycogen and glucose values enhanced after cadmium exposure at both concentrations for 7 days; however, at 0.414mg/L cadmium, protein levels decreased while amino acids and ammonia levels enhanced. An increase in the lactate values was found in plasma after 7 days of exposure and a reduction in the lactate, glucose and protein levels occurred after 14 days of exposure. Results indicated that the metabolic alterations after cadmium exposure were dependent on the tissue type and exposure time. Cadmium exposure for 14 days and recovery period also of 14 days seem to be less harmful to the liver and muscle. However, even after recovering from some changes, fish health may be affected making them more sensitive to some environmental changes.

Toxic Effects of Penoxsulam Herbicide in Two Fish Species Reared in Southern Brazil

Toxic effects of penoxsulam herbicide on acetylcholinesterase, thiobarbituric acid-reactive substances and protein carbonyl were studied in silver catfish (Rhamdia sp.) and carp (Cyprinus carpio). Acetylcholinesterase activity was inhibited in both brain and muscle tissue, with the inhibition being greater in carp than in silver catfish. The levels of malondialdehyde (MDA), an indicator of lipid peroxidation, decreased in silver catfish brain tissue, but increased in the carp brain. MDA also increased significantly in muscle tissue of silver catfish. The levels of protein carbonyl, another measure of oxidative damage, increased in the brain of both fish species, and in the muscle of carp. However, silver catfish exhibited a decrease in muscle protein carbonyl. It appears that silver catfish may possess better mechanisms of defense against penoxsulam toxicity than carp.

Fish anesthesia: effects of the essential oils of Hesperozygis ringens and Lippia alba on the biochemistry and physiology of silver catfish (Rhamdia quelen)

The anesthetic activities of the essential oils (EOs) of Hesperozygis ringens (EOHR) and Lippia alba (EOLA) and their effects in silver catfish (Rhamdia quelen) after anesthesia and recovery were investigated. Fish (32.19±1.24g) were submitted to one of the following treatments for each EO: basal group, control, or anesthesia (150, 300, or 450μLL(-1) EO). After that the anesthesia was induced or simulated and the biometric measurements were completed, fish were transferred to anesthetic-free aquaria to allow for recovery. Fish were sampled at 0, 15, 30, 60, and 240min after recovery. At time 0 of recovery, the ventilatory rate was lower in the groups anesthetized with either EO. In comparison with the basal group, control fish showed an increase in plasma glucose, aspartate aminotransferase (AST), and Na(+) levels and a reduction in Na(+)/K(+)-ATPase activity at 0min of recovery. Plasma levels of ammonia and Na(+) were lower in the fish anesthetized with EOLA (450μLL(-1)) and EOHR (all concentrations), respectively, than in the control fish. Additionally, lactate, AST, alanine aminotransferase, K(+) plasma levels, and gill Na(+)/K(+)-ATPase and H(+)-ATPase activities were higher in the fish anesthetized with either EOHR or EOLA than in the control fish. The EOs promoted slight changes in silver catfish that enabled both an adaptive response and the recovery of most of the measured parameters after 240min regardless of concentration or EO that was used. These findings support the use of EOHR and EOLA as anesthetics for fish.

Physiological and biochemical responses of silver catfish, Rhamdia quelen, after transport in water with essential oil of Aloysia triphylla (L'Herit) Britton

This study investigated the efficacy of the essential oil of Aloysia triphylla in the transport of silver catfish (Rhamdia quelen) considering survival, water quality, ionoregulatory balance and biochemical parameters. Fish (262.0±73.5g) were divided into three groups: 0 (control), 30 or 40μL/L EO of A. triphylla was added to the water and transported in plastic bags for 6h. At the end of transport, dissolved oxygen, alkalinity, pH, temperature, and un-ionized ammonia levels in the water of transport were not significantly different between treatments, but the control group presented the highest total ammonia levels. Fish transported with the EO of A. triphylla had lower plasma cortisol and ion loss and higher plasma Na+ and Cl− levels than control group. Hepatic glycogen, lactate and glucose levels were lower in the liver of fish transported with EO of A. triphylla when compared to the control. Total free amino acids and protein values in the liver were higher in the treatment with 40μL/L EO of A. triphylla. Muscle lactate and glucose levels were higher and lower, respectively, in fish transported with EO of A. triphylla compared to control fish. Thiobarbituric acid-reactive substance levels in the liver and muscle were lower in silver catfish transported with EO of A. triphylla when compared to the control fish. Catalase (CAT) activity was lower in the kidney and higher in the gill of fish transported with EO of A. triphylla when compared to controls. On the other hand, hepatic CAT activity was lower and higher in fish transported with 30 and 40μL/L EO of A. triphylla, respectively, when compared to controls. Protein carbonyl contents of fish transported with EO of A. triphylla were lower when compared to the control. Based on the reduced plasma cortisol levels, ammonia excretion, ionoregulatory changes and improved fish oxidative status, the use of EO of A. triphylla in the water of transport is advisable for fish transportation, 40μL/L being the best concentration.

Addition of Lippia alba (Mill) N. E. Brown essential oil to the diet of the silver catfish: An analysis of growth, metabolic and blood parameters and the antioxidant response

The growth, metabolic and blood parameters and oxidative stress biomarkers effects of adding Lippia alba essential oil (EO) to the diet (0=control, 0.25, 0.5, 1.0 or 2.0mL EO per kg diet) of juvenile silver catfish were investigated for 60days. Liver and muscle were used to measure the glucose, glycogen and lactate levels. Lipid peroxidation (LPO) was assessed as a marker of oxidative damage. Enzymatic antioxidants, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST), and a non-enzymatic antioxidant, non-protein thiols (NPSH), were also quantified in the brain, gills, liver, kidney and muscle. The diet containing L. alba EO did not influence the growth and blood parameters of these animals. However, it reduced glucose levels and increased glycogen reserves in the liver. The diet containing 1.0mL EO per kg diet increased liver lactate levels. In the muscle, the diet containing 0.5mL EO per kg diet increased the glycogen levels. The levels of LPO were measured by determining the thiobarbituric acid reactive substance assay and lipid hydroperoxides, in the gills, liver, kidney and muscle and were also reduced in animals receiving the EO-containing diet; however, no LPO effect was observed in the brain. In turn, the diets containing EO increased the activity of SOD (0.5, 1.0 and 2.0mL EO per kg diet), CAT, GPx, and GST and the NPSH content in the brain; the SOD, GR (2.0mL EO per kg diet) and GST (0.5, 1.0 and 2.0mL EO per kg diet) in the gills; the CAT, GR (2.0mL EO per kg diet) and NPSH levels in the liver; the CAT (0.25, 0.5 and 1.0mL EO per kg diet), GR (1.0 and 2.0mL EO per kg diet) and NPSH (0.5, 1.0 and 2.0mL EO per kg diet) levels in the kidney; and the SOD, GPx (0.5, 1.0 and 2.0mL EO per kg diet) and NPSH (2.0mL EO per kg diet) levels in the muscle. Thus, despite not improving the growth or blood parameters, the addition of L. alba EO to the diet of silver catfish is recommended because it decreases LPO, increases the glycogen and lactate reserves and increases the tissue antioxidant response.

Pro-Inflammatory Cytokines in the Serum of Silver Catfish (Rhamdia quelen) Naturally Infected byClinostomum complanatum: A Preliminary Study

Clinostomum complanatum is a zoonotic parasite of birds, and its larval form (metacercariae) may cause disease in fish. The immune response of fish infected by C. complanatum is unknown, and therefore the objective of this study was to evaluate serum levels of pro-inflammatory cytokines in silver catfish (Rhamdia quelen) infected by this parasite. The analysis showed that fish infected with metacercariae presented significantly (P < 0.05) higher levels of tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) when compared to those not infected. These data suggest that C. complanatum larvae activate the host immune response.

Preference behavior of silver catfish, Rhamdia quelen, juveniles in waters with pH gradients: laboratory experiments

The aim of this study was to determine the preferred pH in silver catfish Rhamdia quelenjuveniles acclimated to different water hardness and the effect of shelters and infection by Ichthyophthirius multifiliis. Fish were acclimated for two weeks at different water hardness levels (4, 24, 50, or 100 mg CaCO3 L-1) and then transferred to a polyethylene tube with a pH gradient ranging from 3.5 to 11.7 and maintaining the same hardness. The position of the fish in the pH gradient was observed at 1, 2, 4, 6, 8, 10, and 12 h after transfer. Acclimation to different water hardness did not change pH preference of uninfected silver catfish (pH 7.30-7.83), and the presence of a shelter at the preferred pH or outside this preferred pH did not change the chosen pH range, either. Consequently silver catfish favored the acid-base regulation over shelter seeking tendency. Juveniles infected with I. multifiliis acclimated to water hardness of 24 mg CaCO3 L-1 preferred alkaline pH (9.08-9.79). This choice is not explained by the higher Na+ levels at alkaline pH compared to neutral pH because infected and uninfected fish choose the same waterborne Na+ levels in a Na+ gradient with the same pH.

Sedative and anesthetic activities of the essential oils of Hyptis mutabilis (Rich.) Briq. and their isolated components in silver catfish (Rhamdia quelen).

This study evaluated the sedative and anesthetic effects of the essential oils (EO) of Hyptis mutabilis (Rich.) Briq. and their isolated components on silver catfish (Rhamdia quelen). Quantitative chemical differences between the EOs obtained from leaves and inflorescences were verified, and a new chemotype rich in globulol was described. Although there were no significant differences in the time of induction for sedation and anesthesia between the EOs, only the leaf EO at 344 mg/L anesthetized all fish without side effects. Fractionation of the leaf EO was carried out by column chromatography. The isolated compounds [(+)-1-terpinen-4-ol and (-)-globulol] showed different activity from that detected for the leaf EO in proportional concentrations and similar sedation to a eugenol control at 10 mg/L. However, fish exposed to 1-terpinen-4-ol (3 and 10 mg/L) did not remain sedated for 30 min. Anesthesia was obtained with 83-190 mg/L globulol, but animals showed loss of mucus during induction and mortality at these concentrations. Synergism of the depressor effects was detected with the association of globulol and benzodiazepine (BDZ), compared with either drug alone. Fish exposed to BDZ or globulol+BDZ association showed faster recovery from anesthesia in water containing flumazenil, but the same did not occur with globulol. In conclusion, the use of globulol in aquaculture procedures should be considered only at sedative concentrations of 10 and 20 mg/L, and its mechanism of action seems not to involve the GABAA-BDZ system.

Efficacy of eugenol and the methanolic extract of Condalia buxifolia during the transport of the silver catfish Rhamdia quelen

This study evaluated extracts of Condalia buxifolia as anesthetics for the silver catfish Rhamdia quelen. The effectiveness of eugenol and of the methanolic extract (ME) of C. buxifolia during the transport of this species was also assessed. Fish of two different weights (1.50±0.02 g and 165.70±22.50 g) were transferred to aquaria containing water with the C. buxifolia ME or with fractions obtained from the ME, such as the n-hexane, dichloromethane, ethyl acetate, n-butane and aqueous fractions, at concentrations from 0-300 °L L-1. The C. buxifolia ME in the 0.5-120 °L L-1range caused only light sedation, and the fractions did not have an effect on the fish. In the second experiment, another group of fish was transported for 12 h in 15 plastic bags. The fish were divided into five groups: control, 1 or 2.5 °L L-1 eugenol and 25 or 50 °L L-1C. buxifolia ME. The non-ionized ammonia levels were lower at the end of transport in the groups with the compounds than in that with water alone. Moreover, both compounds decreased the Na+, Cl-, and K+ net effluxes; therefore, their addition to the water during transport is advisable because they reduce fish mortality and ion loss.

Anesthetic activity of the essential oil of Aloysia triphylla and effectiveness in reducing stress during transport of albino and gray strains of silver catfish, Rhamdia quelen

This study investigated the efficacy of the essential oil (EO) of Aloysia triphylla as an anesthetic for albino and gray strains of silver catfish, Rhamdia quelen. Juveniles were exposed to concentrations between 20 and 800 μL L(-1) EO of A. triphylla to evaluate time of induction and recovery from anesthesia. In another experiment, both strains were divided into four groups such as 0 (control), 30, 40, or 50 μL L(-1) EO and transported for 5 h. The longest time for anesthetic induction and recovery was observed in the albinos. Both strains reached anesthesia in the 100-800 μL L(-1) (11.1-1.24 min) range, without mortality, being 200 μL L(-1) the best response considering time to anesthesia (5.35 min). Albinos transported with all EO concentrations showed higher values of carbon dioxide in the water of transport, but lower levels were observed in grays transported with 40 and 50 μL L(-1) EO when compared to control fish. The same concentrations did not prevent significant whole-body cortisol rise at the end of transport in the albino strain. Juveniles of both strains transported with EO presented lower ion loss to the water compared to control fish. The EO of A. triphylla is an effective anesthetic for albino and gray silver catfish. This EO increases whole-body cortisol levels in the albino strain, but as it reduces net ion loss as in the gray strain, it can be also recommended for transport.