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Amphipods are frequently used as bioindicators of water quality in experimental or behavior trials. Thus, it is a group considered suitable for use as a model organism in tests with essential oils (EOs). This study evaluated the time required for anesthesia induction and recovery of the amphipod crustacean H. bonariensis exposed to the essential oils of Aloysia triphylla (EOAT) and Lippia alba (EOLA), and their major compounds citral and linalool, respectively. In addition, we evaluated the locomotor activity of amphipods using ANY-maze® software. Mortalities were observed at concentrations of 100 and 200 µL/L of citral (50.0 ± 0.39%) and 750 µL/L of EOLA (66.7 ± 0.33%). Except for linalool, increased concentrations of the compounds of the essential oils decreased the time for sedation and anesthesia induction. There were differences for the induction of anesthesia (p < 0.05) and recovery (p < 0.05) between EOLA and linalool treatments, but not between that for EOAT and citral. Reduced locomotor activity and longer time and episodes of freezing were observed in animals exposed to EOAT. The EOs and their major compounds induced anesthesia and affected the locomotor activity of H. bonariensis, Therefore, EOAT and linalool are recommended for anesthesia of this species. EOAT can also be utilized in long-term exposure. [ABSTRACT FROM AUTHOR]

Incorporating essential oils as dietary supplements in aquaculture is increasing in popularity. In prawn farming, their use is associated with reduced disease outbreaks, enhanced immunity, and improved animal growth and welfare. Herein, we explored the use of lemon beebrush essential oil (Aloysia triphylla; EOAT) in the diet of juvenile giant freshwater prawns (Macrobrachium rosenbergii) and its potential impact on growth performance and oxidative status of the hepatopancreas. Four hundred juvenile M. rosenbergii (0.40 ± 0.19 g, similar weights between sexes) were fed diets containing concentrations of EOAT at 0.0% (control), 0.1%, 0.2%, or 0.3% for 50 days. Each experimental group had five replicates, with 20 prawns per experimental unit. Prawn survival remained above 84% for all experimental groups. Prawn weight gain, specific growth rate, feed conversion ratio, and body condition were similar among all experimental groups. Dietary EOAT increased activities of the enzymatic antioxidants, catalase and superoxide dismutase, and varied glutathione S transferase activity in the hepatopancreas of prawns when compared to those fed the control diet. Dietary EOAT did not affect malondialdehyde (lipid peroxidation) levels. While EOAT had no impact on survival and growth of M. rosenbergii, it may modulate the detoxification capacity of the hepatopancreas (i.e., metabolic resistance). Future work should prospect EOAT as part of a nutraceutical blend, especially when combined with known growth enhancers and immune stimulants. Based on our results, dietary inclusion of 0.2% EOAT is the most suitable for juvenile M. rosenbergii farming. [ABSTRACT FROM AUTHOR]

This study evaluated the anaesthetic potential of clove basil (Ocimum gratissimum) essential oil (EO-OG) in the post-larvae (PLs) of M. rosenbergii. The PLs were individually transferred to aquariums (500 mL) containing 50, 100, 150, 200, or 300 μL L−1 EO-OG. A sixth group of PLs was exposed to freshwater only, and a seventh group was exposed to the highest concentration of ethanol used to dilute EO-OG. Upon reaching the anaesthesia stage, the PLs were transferred to aquariums (500 mL) with freshwater only to evaluate the recovery time. The shortest sedation times were observed at 200 (15.98 s) and 300 μL L−1 (25.85 s). The shortest anaesthesia time was observed at 200 μL L−1 (22.52 s). The longest recovery time was observed at 100 μL L−1 (1367.10 s); the shortest recovery time was observed at 150 μL L−1 (630.10 s). No mortality or adverse effects were observed in any experimental group. The concentration of 150 μL L−1 resulted in sedation (49.24 s), anaesthesia (80.10 s), and recovery (630.10 s) times within those suggested as adequate for freshwater prawn farming. This research demonstrated the sedative and anaesthetic properties of EO-OG and its potential application in prawn farming. This study recommends using 150 μL L−1 of EO-OG in M. rosenbergii PLs. [ABSTRACT FROM AUTHOR]

Mugil liza juveniles (6.69 ± 0.06 g) were subjected to dietary citral (0-control, 0.5, 1.0 and 2.0 mL per kg feed) for 45 days, and its possible effects on zootechnical and metabolic parameters, digestive enzymes, innate immunity, oxidative status and liver damage were evaluated. At the end of the experiment, fish fed 2.0 mL citral per kg feed showed a greater weight gain and protein retention efficiency, as well as enhanced activities of pepsin (stomach) and amylase (intestine) compared with control fish. Citral supplementation decreased liver lipoperoxidation and increased the activities of glutathione peroxidase, glutathione-S-transferase and superoxide dismutase in the gills, liver and brain. The highest level of citral inclusion augmented non-protein thiol content in the brain and gills. Myeloperoxidase activity was lower in fish offered 1.0 and 2.0 mL citral per kg feed. Dietary citral did not influence the plasma levels of aspartate aminotransferase and alanine aminotransferase or the hepatic histology. As it improved growth, the activity of digestive enzymes and general health, dietary citral may be recommended for M. liza at 2.0 mL per kg feed. [ABSTRACT FROM AUTHOR]

The increasing concern for invertebrate welfare has led to improvements in management procedures and protective legislation; under discussion is the use of anaesthetic agents to improve the welfare of farmed prawns. In parallel, the aquatic environments present changes in their physical and chemical characteristics, like the acidification of waters. With this perspective, our study analysed the effectiveness of Ocimum gratissimum essential oil (EO-OG) as a natural anaesthetic for Macrobrachium rosenbergii at different concentrations and water pHs. Juvenile M. rosenbergii were exposed to five different EO-OG concentrations (0, 100, 200, 300, and 400 μL L−1) and vehicle control (ethanol), at two water pHs (8.08 ± 0.10 and 6.42 ± 0.15). Induction time was EO-OG concentration-dependent regardless of water pH; i.e. the time required for sedation and anaesthesia decreased with the increase of EO-OG concentration. No correlation was found between recovery time and EO-OG concentration. The most effective EO-OG concentration was 400 μL L−1, with prawn sedation in 2.0–2.5 min, anaesthesia in 3.5–4.1 min, and full recovery in 16 min, regardless of water pH. The different tested water pHs influenced sedation time; i.e. sedation time was higher in mild acidic water than in mild alkaline water. Anaesthesia induction and recovery times were similar at both water pHs. Survival rates were 100% in all experimental groups. In summary, EO-OG is effective as a sedative and anaesthetic for juvenile M. rosenbergii in routine procedures, at the recommended concentration of 400 μL L−1, with mild alkaline water. [ABSTRACT FROM AUTHOR]

Anesthetic effect of Aloysia triphylla and Lippia alba essential oils (EOs) in the Amazonian fish Serrasalmus eigenmanni was evaluated. The fish were placed in aquaria containing A. triphylla or L. alba EOs (25 to 200 μL L-1). Then, fish were transferred to aquaria containing EO-free water to evaluate their recovery time. In another experiment, fish were transferred to aquaria containing A. triphylla or L. alba EOs (3 to 10 μL L-1) and swimming behavior was analyzed for up to 240 min of exposure. Water samples were collected at 0 and 240 min and blood samples were collected at 240 min. Tested concentrations induced all stages of anesthesia, except 25 μL L-1 A. triphylla EO and 50 μL L-1 L. alba EO, which only induced sedation. Prolonged exposure to both EOs reduced swimming time compared to the control at all evaluated times. The fish exposed to 3 μL L-1 A. triphylla EO showed a lower net K+ efflux compared to ethanol-exposed fish; in those exposed to 5 μL L-1, ammonia excretion was reduced. The blood parameters did not show significant differences between treatments. In conclusion, both EOs can be used as anesthetics and sedatives for transport of S. eigenmanni. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the season that provides the highest production and best quality of peppermint (Mentha x piperita L.) essential oil in summer and winter transplantations. Two experiments were performed in a protected cultivation, the first with transplantation in summer and the second with transplantation in winter, with a completely randomized design with four treatments, being the seasons of the year. Content, yield and chemical composition of the essential oil were determined. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography. Essential oil content in summer and winter transplantations was higher in summer and essential oil yield was higher in spring. In the summer transplanting the major components were menthone, isomenthone and pulegone. In the winter transplanting menthone, menthofuran, isopulegone, pulegone and menthol were detected as major components. Menthofuran, a compound which reduces the essential oil quality, were found in high amounts in winter transplanted plants. The higher production of peppermint essential oil is obtained in summer and spring harvests and the main compound is menthone in all seasons. The best quality of essential oil is obtained in the summer transplanting. [ABSTRACT FROM AUTHOR]

This study evaluated the anesthetic activity of essential oil from Lippia alba (EOLA), linalool chemotype in a euryhaline fish (fat snook Centropomus parallelus). In the first experiment, fish were exposed to 30, 80, 130, 180, 200, and 230 µL EOLA L-1. The second experiment evaluated smaller and larger fish with 180 µL EOLA L-1. In the third experiment, ventilatory rates (VR) for up to 120 min in animals during exposure to 5 and 10 µL EOLA L-1 were evaluated. In the fourth experiment, fish anesthetized with 30 and 180 µL EOLA L-1 were assessed at 0, 30, and 60 min after anesthesia recovery to evaluate biochemical and antioxidant parameters. The best mild and deep anesthesia times were obtained with 30 and 180 µL EOLA L-1, and larger fish had the highest times. The VR increased in fish exposed to EOLA. Blood glucose and whole-body cortisol levels were higher in fish anesthetized with 180 µL EOLA L-1. Fish exposed to EOLA had higher liver glutathione S-transferase and superoxide dismutase activities without affecting catalase and lipid peroxidation levels. The 180 µL EOLA L-1 is recommended for fat snook anesthesia because it increases VR, blood glucose, and whole-body cortisol levels and prevents oxidative stress. [ABSTRACT FROM AUTHOR]

Nectandra grandiflora Nees (Lauraceae) is a Brazilian native tree recognized by its durable wood and the antioxidant compounds of its leaves. Taking into account that the forest industry offers the opportunity to recover active compounds from its residues and by-products, this study identifies and underlines the potential of natural products from Nectandra grandiflora that can add value to the forest exploitation. This study shows the effect of three different extraction methods: conventional (CE), ultrasound-assisted (UAE) and microwave-assisted (MAE) on Nectandra grandiflora leaf extracts (NGLE) chemical yields, phenolic and flavonoid composition, physical characteristics as well as antioxidant and antifungal properties. Results indicate that CE achieves the highest extraction phytochemical yield (22.16%), but with similar chemical composition to that obtained by UAE and MAE. Moreover, CE also provided a superior thermal stability of NGLE. The phenolic composition of NGLE was confirmed firstly, by colorimetric assays and infrared spectra and then by chromatographic analysis, in which quercetin-3-O-rhamnoside was detected as the major compound (57.75–65.14%). Furthermore, the antioxidant capacity of the NGLE was not altered by the extraction methods, finding a high radical inhibition in all NGLE (>80% at 2 mg/mL). Regarding the antifungal activity, there was observed that NGLE possess effective bioactive compounds, which inhibit the Aspergillus niger growth. [ABSTRACT FROM AUTHOR]

Hesperozygis ringens (Benth.) Epling is an endangered Lamiaceae woody herb characterized by the abundance of essential oil (EO) in its leaves. However, no information has been found in literature about the plant tissues where this extractive is biosynthesized, and what other constituents are produced by the organ. In addition, the classes of compounds biosynthesized by its petals and the composition of EO produced by the inflorescences have not been reported either. Because this information may help the H. ringens identification, the aim of this study was to characterize the compound classes in the plant leaf and petal by histochemical tests. The leaves and flowers of this species were collected from a population in Santo Antão, municipality of Santa Maria, Rio Grande do Sul, Brazil. Fresh plant material was analyzed to detect total lipids; acid and neutral lipids; essential oils (EOs), resins and oil-resins; proteins; starch; phenolic compounds; tannins; flavonoids; and alkaloids. The EOs of leaves and inflorescences were extracted by hydrodistillation and their chemical compositions were analyzed by gas chromatography coupled to mass spectrometry (GC–MS) and GC with flame ionization detector. Results obtained in histochemical tests detected total, neutral and acid lipids, EOs, oil-resins, protein, phenolic compounds, flavonoids and alkaloids in the leaves and petals of H. ringens . Total lipids were found mainly in leaf mesophyll and glandular trichomes of both plant organs. Essential oils were marked in leaf vascular bundle, petal surface and glandular trichomes of both fresh organs. Oil-resins were detected mainly in leaf mesophylls and petal glandular trichomes. The chemical characterization of the EOs produced by leaves and inflorescences detected the oxygenated monoterpenoid pulegone as their major compound. The species presented histochemical characteristics which have not been found for other Lamiaceae representatives yet, and may serve to identify H. ringens . [ABSTRACT FROM AUTHOR]

The present study evaluated different levels of the essential oil of Nectandra grandiflora (EONG) in the diet of juvenile Colossoma macropomum. The juveniles (0.75 ± 0.05 g) were fed four experimental diets with differing levels of EONG (0, 0.5, 0.75, and 1.50 mL/kg). After 20 days, the weight, daily weight gain, specific growth rate, and daily feed consumption per fish were highest for the fish fed 0.5 mL EONG/kg, while after 30 days, only the weight and daily feed consumption per fish for that diet remained highest. The viscerosomatic index was highest for the fish fed 0.5 mL EONG/kg while the hepatosomatic index was higher for the groups that received dietary EONG for 30 days. The juveniles fed 1.5 mL EONG/kg showed a proliferative response of the mucous cells in the gills, but the proliferation of these lysozyme- and immunoglobulin-secreting mucosal cells was higher for the skin of the fish of all EONG levels, compared to that of the control fish. The fish fed 0.5 mL EONG/kg had the greatest height and width of intestinal villi. The two highest levels of dietary EONG supplementation (0.75 and 1.50 mL/kg) reduced the hepatocyte dimensions but did not modify the centrolobular vein area. Dietary supplementation with 0.5 mL EONG/kg improved the growth, gut health, and immune response of juvenile C. macropomum. [ABSTRACT FROM AUTHOR]

This study evaluated the effectiveness of the essential oil of Hesperozygis ringens (EOHR) for anesthesia of Colossoma macropomum by documenting hematological and blood biochemical responses after biometric handling. In Experiment 1, juveniles (14.12 ± 3.53 g) were exposed to different concentrations of EOHR: 0 (control), 75, 150, 300 and 450 µL L-1 (n=10 fish for each concentration), to determine times for induction and recovery from anesthesia, as well as its effects on ventilatory frequency (VF). Based on these results, Experiment 2 evaluated the effects of 0 (control), 75 (with induction and recovery times outside that recommended for fish anesthesia) and 150 µL L-1 EOHR (within recommended times) on hematological and biochemical variables of juveniles (20.52 ± 3.47 g) after anesthesia and after 24 h of recovery (n = 6 fish for each concentration and collection time). Survival was 100%. Induction time showed a quadratic effect of EOHR concentration. Recovery time did not differ among EOHR concentrations. Concentrations between 150 and 450 µL L-1 EOHR caused rapid induction (< 3 min) and recovery (< 5 min). EOHR concentration affected VF. The concentration of 150 µL L-1 EOHR had little influence on hematological and biochemical parameters of C. macropomum of 20 g. [ABSTRACT FROM AUTHOR]

The sea urchin,Echinometra lucunter, is consumed in restaurants in Europe and Asia for high prices. This study evaluated the use of the essential oil ofLippia alba(EOL) as a sedative and anesthetic in this sea urchin. Different EOL concentrations were tested (50, 100 and 150 μL L−1), in addition to a group that received ethanol and a control group. After the anesthesia and recovery from the different treatments, the coelomic fluid, gonads and intestine were collected for the analysis of oxidative stress parameters. The highest concentration tested (150 μL L−1) was determined to be the optimal concentration for anesthesia. Results suggest that EOL improved the response to oxidative stress, since a lower level of thiobarbituric acid-reactive substances and greater superoxide dismutase and catalase activities were observed in the coelomic fluid andE. lucuntergonads, making the EOL a promising anesthetic for sea urchins. [ABSTRACT FROM AUTHOR]

The essential oil of Aloysia triphylla (EOAT) is a promising product with potential use in aquaculture systems. This study evaluated hematological/biochemical responses and survival of silver catfish ( Rhamdia quelen ) fed a diet containing EOAT and infected by Aeromonas hydrophila . After 21 days of feeding trial, fish were infected with A. hydrophila following a 10-day period of observation. Blood collection was performed before and after the bacterial challenge. Dietary EOAT by itself seems to affect some blood parameters, decreasing total leukocyte, lymphocyte, and neutrophil counts and increasing total protein values. However, 2.0 mL EOAT/kg diet showed a possible potential protective effect after A. hydrophila infection, maintaining the evaluated parameters similar to basal values (from healthy fish before the feeding trial) and promoting survival of silver catfish. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the biological effects of dietary supplementation with 0.05% and 0.1% cinnamon essential oil extracted from Cinnamomum cassia on silver catfish (Rhamdia quelen). The final body weight, weight gain, and specific growth rate were significantly higher in fish supplemented with 0.05% cinnamon essential oil than in the control(untreated) group. Muscle reactive oxygen species and lipid peroxidation levels were significantly lower in fish supplemented with 0.05% cinnamon essential oil but higher at the 0.1% concentration. Muscle antioxidant capacity against peroxyl radicals (ACAP) and superoxide dismutase activity were significantly higher in fish supplemented with 0.05% cinnamon essential oil, while ACAP levels were lower in fish supplemented with 0.1%. The total saturated fatty acid content was significantly higher in the muscle of supplemented fish than in controls, while the total monounsaturated fatty acid content was significantly higher only in fish fed 0.1% cinnamon essential oil. Finally, the total content of polyunsaturated fatty acids was significantly lower in fish fed 0.1% essential oil. Thus, data demonstrated that 0.05% C. cassia essential oil improves fish health by improving performance and muscle oxidant/antioxidant status. Higher doses of cinnamon essential oil produced oxidative stress in muscle, suggesting toxicity at the 0.1% level. Although this cinnamon essential oil diet exerted positive health effects, this diet impaired the muscle fatty acid profile, suggesting adverse impacts on human health. [ABSTRACT FROM AUTHOR]

Essential oils are considered to have the ability to minimize the effects of stress during handling in aquatic animals. This study evaluated the anesthetic effects of Lippia alba essential oil and its major compound, linalool, on the antioxidant responses of eyestalk-ablated female shrimp Litopenaeus vannamei. Female shrimp were divided into the following treatments: pure seawater (control), ethanol (9000 μL L−1 of ethanol), 750 μL L−1 of Lippia alba essential oil, 1000 μL L−1 of Lippia alba essential oil, 350 μL L−1 of linalool, and 500 μL L−1 of linalool. The shrimp were sedated for 3 min. The eyestalks were then ablated unilaterally by cauterization (cutting the eyestalk with hot scissors). Biochemical variables were analyzed in the gill, muscle, and hepatopancreas. The antioxidant capacity against peroxyl radicals in the group that received 750 μL L−1 of Lippia alba essential oil was significantly higher in the hepatopancreas and muscle than in the control group, whereas the ethanol group had a higher antioxidant capacity in the gills and muscle than the control group. An increase in the total antioxidant capacity in the hepatopancreas and muscle was observed in the 750 μL L−1 Lippia alba essential oil group, but not in the ethanol group, relative to the control group. A significant reduction in lipid peroxidation in the gills was observed in females treated with 500 μL L−1 of linalool compared to the ethanol group. Linalool and Lippia alba essential oil contributed to the improvement in the antioxidant defense systems of shrimp gills. Overall, the obtained results suggest that exposure to Lippia alba essential oil and linalool may activate certain components of the antioxidant system that exist in the gills and scavenge peroxyl radicals; this in turn may help maintain homeostasis and improve the welfare of eyestalk-ablated female shrimp. • Female shrimp anesthetized with the essential oil of L. alba were eyestalk-ablated • Anesthesia increased the antioxidant capacity in the hepatopancreas and muscle • Linalool and L. alba essential oil improved the antioxidant defense systems of gills • Anesthesia with linalol decreased TBARS levels in the gills • Linalol and L. alba essential oil maintained homeostasis of eyestalk-ablated females [ABSTRACT FROM AUTHOR]

This study evaluated the anesthetic and sedative effects of the essential oil of Hesperozygis ringens (EOHR) on juveniles Colossoma macropomum. Experiment 1 exposed juveniles (3.35 ± 0.73 g) to 0 (control), 75, 150, 300 and 450 µL L− 1 of EOHR, with 10 replications each. Induction time showed a quadratic effect (R2 = 0.8628), while recovery time showed a direct linear effect (R2 = 0.7527). Concentrations between 150 and 450 µL L− 1 EOHR are therefore recommended for use as anesthetic for C. macropomum. Experiment 2 evaluated 0, 5, 15 and 30 µL L− 1 of EOHR for two periods of transport (4 and 24 h) of juveniles (1.46 ± 0.58 g) in 32 plastic bags (30 × 40 cm) containing 1 L of water, 2/3 of pure oxygen with 10 fish per bag. All EOHR treatments had lower dissolved oxygen (DO) after 24 h, while 15 and 30 µL L− 1 EOHR had lower non-ionized ammonia after 4 and 24 h. Experiment 3 used the same procedures as Experiment 2 for 24 h of transport with juveniles (1.77 ± 0.58 g) in 16 plastic bags at the same density (10 fish L− 1). Concentrations of 15 and 30 µL L− 1 EOHR had lower pH after 24 h and all EOHR treatments had lower DO. No mortality was observed. Experiment 4 tested the same concentrations of EOHR evaluated in Experiment 2 but using 16 plastic bags without fish. The concentrations of 15 and 30 µL L− 1 EOHR had lower DO and pH after 24 h. [ABSTRACT FROM AUTHOR]

Hesperozygis ringens is a species that stands out for the production of essential oil. No reports on the leaf spectral characterization of the species have been found. This study aimed to determine the reflectance pattern of Hesperozygis ringens leaves with the aid of Remote Sensing. Therefore, a spectroradiometer that operates in the continuous spectral range from 400 to 900 nm of the electromagnetic spectrum was used, with a resampled precision of 1 nm. The reflectance measurement was collected in situ. Four records were obtained. A spectral curve was created from the means of measurements in each sample. In the blue region, reflectance values between 0.0116696 and 0.0399550 were found. In the red region, the reflectance oscillated between 0.0438487 and 0.1095826. In the green region, the reflectance values ranged between 0.0405677 and 0.1001319. In the near-infrared region, the oscillation of reflectance values occurred between 0.1163483 and 0.4655269. The results indicate the effectiveness of the use of geotechnologies to carry out the spectral characterization of the H. ringens leaf. Further studies are expected to identify and monitor plant populations with Remote Sensing. [ABSTRACT FROM AUTHOR]

The objective of this exploratory work was to analyze the yield and chemical composition of essential oils (EO) from Blepharocalyx salicifolius [BS] and from two pools of EO obtained from Nectandra megapotamica [NM1 and NM2], as well as to evaluate their antifungal properties against the fungi Pycnoporus sanguineus (whiterot) and Gloeophyllum trabeum (brown-rot). The EO were obtained by hydrodistillation and its components were identified by gas chromatography coupled to mass spectrometry (GC-MS) and quantified with flame ionization detection (GC-FID). For the evaluation of antifungal activity, the mycelial growth index (MGI) and the mycelial growth inhibition (GI) of BS were determined at concentrations of 1, 2 and 5 µL.mL-1, and 0.25; 0.5 and 1 µL.mL-1 for MN1 and NM2. The yield of EOs was 2.29% (BS), 0.14% (NM1) and 0.17% (NM2). The major components of BS EO were eucalyptol (63.44%) and β-caryophyllene (13.68%), from NM1 were bicyclogermacrene (16.14%) and α-pinene (15.93%), and for NM2, α-pinene (19.04%) and sabinene (16.66%). EO NM1 (1μL.mL-1 ) showed the best result for antifungal activity, inhibiting about 57.55 ± 0.68 % of P. sanguineus growth and 58.82 ± 0.78 % in the test with G. trabeum. [ABSTRACT FROM AUTHOR]

To verify the efficacy of citral in inducing sedation and anesthesia in silver catfish (Rhamdia quelen) and grass carp (Ctenopharyngodon idella) and to assess the safety of essential oil (EO) of Aloysia citriodora and citral in inducing and maintaining anesthesia in silver catfish. Clinical study, randomized, parallel, multi-arm with control group in target species. A total of 96 juvenile and 72 adult silver catfish and 80 juvenile grass carp were used. Silver catfish and grass carp were exposed to different concentrations of citral, 15–675 and 15–600 μL L–1, respectively, during the maximum period of 30 minutes to verify sedation and anesthesia induction and recovery times. In addition, for anesthetic induction, silver catfish were exposed to the EO of A. citriodora and citral at 225 μL L–1 for 3.5 minutes. Then, fish were transferred to an anesthesia maintenance solution at 50 μL L–1 for 10 minutes to assess hematologic and biochemical variables at 60 minutes, 2 and 6 days after treatment. Citral only induced sedation from 15, 25 and 40 μLL–1 in both species. Anesthesia without mortality was induced in silver catfish at 50–600 μL L–1 and grass carp at 75–450 μL L–1. At 675 and 600 μL L–1, mortality was recorded in silver catfish and grass carp, respectively. The EO of A. citriodora and citral were safe in inducing and maintaining anesthesia in silver catfish, with mean corpuscular hemoglobin concentration being the only variable that varied in relation to time and treatments. Citral was effective in inducing sedation and anesthesia in both species. In addition, A. citriodora EO and citral were safe in inducing and maintaining anesthesia in silver catfish. Both agents are promising substances for the development of new drugs for fish. [ABSTRACT FROM AUTHOR]

The use of anesthetics in aquaculture ensures better animal welfare and survival during transport and the production cycle. The present study evaluated the anesthetic efficacy of essential oils (EOs) of Lippia alba (EOLA) and Ocimum gratissimum (EOOG) for pink shrimp Farfantepenaeus paulensis, and EOs of Origanum majorana (EOO) and Cymbopogon citratus (EOC) for white shrimp Litopenaeus vannamei. shrimp were exposed to (i) 500, 750 or 1000 μL L-1 of EOLA or (ii) 50, 100, 150 or 250 μL L-1 of EOOG, and L. vannamei were exposed to (iii) 150, 300 or 500 μL L-1 of EOC or (iv) 400 or 800 μL L-1 of EOO. The induction times were concentration dependent, with a decrease in induction time with the increase of the EOs concentration, but for EOLA, this pattern was observed only for anesthesia. Induction times for sedation and anesthesia were significantly shorter for shrimp exposed to EOC and EOO. The highest concentration of EOOG (250 μL L-1) resulted in 30% mortality. The recovery time was significantly longer for shrimp exposed to 800 μL L-1 of EOO compared to the other EOs. Overall, the action of EOs significantly differed between the two shrimp species. In conclusion, the tested EOs effectively anesthetized F. paulensis and L. vannamei. [ABSTRACT FROM AUTHOR]

There is growing interest for using essential oils (EOs) in fish feed as they can improve fish health, growth, and productive yield. But, there is little information concerning their effects on fish flesh quality and whether EO residues can be found in flesh. The EO of lemongrass was recently demonstrated to increase the productive yield of silver catfish. Thus, the aim of this study was to evaluate the impact of lemongrass EO supplementation on physico-chemical properties, sensory acceptance, and stability during frozen storage of fish fillets. Silver catfish (Rhamdia quelen) were fed diets containing 0, 1, or 3 mL/kg of EO for 20 days. Fish were slaughtered, and fillets were stored at −20°C for 12 months and evaluated every 90 days. Dietary supplementation with EO did not affect proximate composition, fatty acid composition, or sensory acceptance of fish fillets. EO constituents (especially citral) were not detected in fish fillets. EO supplementation at 1 mL/kg appears to be more suitable to maintain physico-chemical changes similar to control during frozen storage. These data support the safety of lemongrass EO for use in aquaculture for human consumption purposes. [ABSTRACT FROM AUTHOR]

Maclura tinctoria is a tree species native from Brazil and rich in phenolic compounds. Since plant antibacterial activity is highly associated with phenolic compound concentration, we aim to evaluate the in vitro antimicrobial activity of different extracts against fish pathogenic bacteria. In addition, some phenolic compounds have central depressant effects and can be useful in aquaculture due to possible sedative and/or anesthetic effects. Four M. tinctoria extracts were extracted separately with ethanol; leaves (LE), bark (BE), heartwood (HE), and the sapwood (SE). In vitro antimicrobial activity was tested against Aeromonas strains at concentrations of 6400 to 3.125 μg/mL. The sedative effect was evaluated for 24 h with 30 and 100 mg/L concentrations. Chemical composition was analyzed by HPLC-DAD-MS. The HE extract had the best MIC (400 μg/mL) and MBC (800 μg/mL) compared to the LE, BE, and SE extracts. LE extract induced deep sedation and the BE, SE, and HE extracts induced light sedation. Additionally, BE, SE, and HE induced a normal behavior without side effects. Polyphenolic compounds with antimicrobial activity and sedative effects were identified mainly in HE. Thus, HE extract is safe and can be used as a sedative for silver catfish. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the antifungal potential of the essential oil (EO) from Hesperozygis ringens leaves and its major compound pulegone against wood-decay fungi. In addition, their effect on mycelia ergosterol content was assayed. The EO was extracted by hydrodistillation and its chemical composition was analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. Pulegone was isolated through column chromatography. The EO and pulegone were tested on white-rot fungi (Ganoderma applanatum and Trametes versicolor), and brown-rot fungi (Gloeophyllum trabeum and Lentinus lepideus) in five and three concentrations, respectively. Propiconazole was used as positive control. The EO inhibited T. versicolor growth while pulegone inhibited growth of both white-rot species. Pulegone presented lower half-maximal inhibitory concentration than the EO for white-rot fungi. Both EO and pulegone negatively affected white-rot fungi ergosterol contents. White-rot fungi, in general, were more susceptible to EO and pulegone. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the season that promotes the highest production and best quality of marjoram (Origanum majorana L.) essential oil in summer and winter transplantations. Two experiments were performed in a protected cultivation, the first with transplanting in summer and the second with transplanting in winter, with a completely randomized design with four treatments, corresponding to the seasons of the year. Content, yield, and chemical composition of the essential oil were determined. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography. In the summer transplanting, the essential oil content and yield were higher in the summer and spring seasons. In the winter transplanting, the essential oil content was higher in the summer season and the yield in summer and spring. Carvacrol was the major component of marjoram essential oil regardless of harvest and transplanting season. Of the other main compounds, only terpinolene was detected in all samples analyzed, with the other essential oil components varying between transplanting and harvest seasons. The highest production of marjoram essential oil is obtained in summer and spring harvests from plants transplanted in summer and winter. Carvacrol was the major component of marjoram essential oil and the other main components vary among seasons. [ABSTRACT FROM AUTHOR]

In the present study we evaluated the chemical composition and allelopathic activity of the essential oil (EO) of Blepharocalyx salicifolius (Kunth) O. Berg leaves on the germination and initial growth of Lactuca sativa L. (dicotyledonous) and Sorghum bicolor (L.) Moench (monocotyledon). EO was obtained by hydrodistillation for 3 h. The EO composition analysis was performed by gas chromatography coupled to a mass spectrometry (GC-MS). The allelopathic activity of EO was evaluated at 2.5; 5.0 and 7.5%. The seeds were immersed in the solution for 2 min., distributed in Petri dishes, that were maintained in a BOD incubator. On the seventh day, the variables germination (%), root length (cm), shoot length (cm) and total seedling length (cm) were evaluated. The major constituents identified in the OE were eucalyptol (49.6%), limonene (13.6%) and β-caryophyllene (12.2%). The EO affected negatively the germination percentage of L. sativa seeds and the root system and total seedling length of S. bicolor. There was a negative allelopathic activity against the two evaluated species. [ABSTRACT FROM AUTHOR]

The effects of dietary supplementation with Citrus × latifolia essential oil (EOCL: 0, 0.25, 0.5, 1.0 and 2.0 ml EOCL/kg diet) on growth, survival, gut tract morphology and the metabolic and oxidative parameters of tambaqui (Colossoma macropomum) were investigated in a 60‐day experiment. The inclusion of up to 2.0 ml EOCL/kg diet did not promote growth; however, fish fed 1.0 and 2.0 ml EOCL/ kg diet presented higher survival and all EOCL groups had increased intestinal fold height and length compared to the control group. After 60 days of experiment, glucose, glycogen, lactate and protein levels in the liver and muscle were altered significantly by dietary addition of EOCL. The muscle LPO content was higher in fish fed 2.0 ml EOCL/ kg diet than the control group. The reactive oxygen species content was higher in the liver but lower in the muscle of fish fed 1.0 ml EOCL/kg diet compared to the control group. SOD activity was higher in the liver of fish fed 0.50 and 1.0 ml EOCL/kg diet than the control group. Therefore, dietary addition of 1.0 ml EOCL/kg diet is advisable for tambaqui juveniles since it improved survival, the antioxidant capacity of tissues and the intestinal absorption area. [ABSTRACT FROM AUTHOR]

Plants are sources of secondary metabolites, and some are rich in essential oils (EOs), which possess a bioactive pharmacological importance as sedatives and anaesthetics that have been experimentally demonstrated in fish. In search of products with lower residual effects and optimization of the production based on the local flora, the properties of the EO of Aloysia triphylla (EOAT) have been investigated. The samples of two years were analysed for the percentage variability of the chemical composition and the totality of the major components according to the season. Limonene, citral isomers (α and β), caryophyllene, caryophyllene oxide and spathulenol were the main constituents of the EOAT throughout these two years. In the second year, caryophyllene predominates over its oxide in all seasons; however, in the first year, it occurs only in autumn and winter. Seasonal pools of EOs were made for the biennium obtaining four samples, and silver catfish (Rhamdia quelen) juveniles were subjected to a concentration range of 20–800 μl/L EOAT in order to assess induction and recovery times of anaesthesia. The relationships between percentages of individual components in EOAT and time to induce deep anaesthesia indicate that its activity may be attributed to the association of several of its components. [ABSTRACT FROM AUTHOR]

The juveniles of Macrobrachium rosenbergii (0.060 ± 0.004 g and 2.018 ± 0.071 cm) were fed during 60 days with diets containing different doses of Lippia alba essential oil (EOLA) (0.0—control, 1.0, or 2.0 ml EOLA/kg diet; in triplicate, with 20 prawns/replicate). After the experimental period, were verified the survival, growth parameters and the antioxidant enzymes, lipid peroxidation and Na/K‐ATPase activities in hepatopancreas and gills, respectively, of the animals. There were no significant differences on survival, growth parameters and gill Na/K‐ATPase activity. However, glutathione peroxidase and glutathione‐S‐transferase activities were lower in hepatopancreas of prawns fed with 1.0 ml EOLA/kg diet compared to the control. Moreover, the activity of the enzyme superoxide dismutase was higher in hepatopancreas of prawns that received 2.0 ml EOLA/kg diet compared to those fed with 1.0 ml EOLA/kg diet. Although the addition of both EOLA doses has not improved the survival and growth parameters of M. rosenbergii, these doses contributed to decrease lipid peroxidation. Additionally, the dose of 2.0 ml EOLA/kg diet contributed for increasing the antioxidant enzymes activities in the hepatopancreas, improving antioxidant status, and therefore, it can be recommended as diet supplementation for M. rosenbergii. [ABSTRACT FROM AUTHOR]

Nectandra grandiflora Ness (Lauraceae) essential oil (EO) main constituent, the sesquiterpenoid (+)-dehydrofukinone (DHF), has sedative and anticonvulsant effects through GABAergic mechanisms. Other DHF-related sesquiterpenoids have been identified in the EO, such as, dehydrofukinone epoxide (DFX), eremophil-11-en-10-ol (ERM) and selin-11-en-4-α-ol (SEL). However, the neuronal effects of these compounds in mammals remain unknown. Therefore, the aim of this study was to evaluate the anxiolytic potential of the N. grandiflora EO and the isolated compounds in in mice. For this purpose, mice were administered orally with vehicle, 10, 30 or 100 mg/kg EO, DHF, DFX, ERM or SEL or 1 mg/kg diazepam. Locomotion and ethological parameters in the open field (OF) and elevated plus maze (EPM) were recorded. We also examined the effect of DFX, ERM and SEL on the membrane potential and calcium influx in synaptosomes, and the presence of the compounds in the cortical tissue using gas chromatography. EOs and isolated compounds reduced anxiety-related parameters in the EPM (open arms time and entries, end activity, head dipping) and OF (center time and entries, total rearing, unprotected rearing, sniffing, grooming) without alter ambulation or induce sedation. Flumazenil (2 mg/kg, i.p.) altered the anxiolytic-like effect of all treatments and vanished the DFX, ERM and SEL-induced changes in membrane potential. However, FMZ did not blocked the DFX-, ERM- and SEL-induced inhibition of calcium influx. Therefore, our results suggest that N. grandiflora EO and isolated compounds induced anxiolytic-like effect in mice due to positive modulation of GABAa receptors and/or inhibition of neuronal calcium influx. Unlabelled Image • N. grandiflora EO and its isolated compounds blunt anxiety-like behavior in mice. • EO and compounds induced anxiolytic-like effect without sedation. • GABAa receptors play a role in the EO and compounds anxiolytic-like effect. • Isolated compounds altered the synaptosomal membrane potential and calcium influx. • Calcium influx inhibition by compounds did not required GABAa receptors. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the anesthetic effect of the essential oils (EOs) of Lippia alba (citral and linalool chemotypes, EOLA-C and EOLA-L respectively) and Lippia origanoides (chemotype carvacrol, EOLO-Ca) on tambaqui (Colossoma macropomum) juveniles. The tested concentrations of the L. alba and L. origanoides EOs were: 25, 50, 100, and 200 µL/L. Time required to reach the stages of sedation, deep anesthesia, and recovery, as well as ventilatory frequency, were monitored for each EO concentration. The results indicated that all EO concentrations tested induced tambaqui anesthesia and that the ventilatory frequency was altered by the EOs. L. origanoides showed the shortest time to induce sedation and anesthesia, but had long recovery times. L. alba EO (citral 100 µL/L and linalool 200 µL/L) can be used to efficiently anaesthetise tambaqui juveniles with an efficient recovery. [ABSTRACT FROM AUTHOR]

S -(+)-linalool is a phytochemical with proven sedative and anesthetic effects in silver catfish (Rhamdia quelen); however, the pharmacokinetic profile of this compound in fish remains unknown. Therefore, this study describes the pharmacokinetics of S -(+)-linalool in silver catfish anesthetized by immersion bath. Fish were exposed to 153 mg/L S -(+)-linalool for a maximum of 30 min. Blood and brain samples were collected at several time-points up to 4.0 h (0.5 h of anesthesia and 3.5 h of recovery) after the onset of exposure. Before each tissue/blood sampling, the anesthesia stage of each animal was recorded. Following S -(+)-linalool quantification in plasma and brain tissue by gas chromatography with flame ionization, concentration curves were constructed for determination of the pharmacokinetic parameters. S -(+)-linalool in the plasma and brain was detected within the first 2 min (0.03 h) of exposure, with maximum times (T max) of 0.50 and 0.33 h and maximum concentrations (C max) of 129.33 μg/mL and 113.92 μg/g, respectively. Other parameters estimated for the plasma and brain were terminal half-lives (T 1/2β) of 1.36 and 57.27 h, elimination constants (K el) of 0.50 and 0.01/h, areas under the curve from zero to 4.0 h (AUC 0–t) of 120.98 μg/mL/h and 250.57 μg/g/h, and AUCs from zero to infinity (ASC 0–∞) of 132.15 μg/mL/h and 4946.13 μg/g/h, respectively. After 10 min (equivalent to a collection time of 0.66 h) in a drug-free bath, all animals recovered from anesthesia. These results suggest that S -(+)-linalool is promptly absorbed into the bloodstream and widely distributed to the brain. Elimination is efficient in plasma but slower in the brain, yet this factor does not impair the recovery of animals, which occurs quickly. Therefore, S -(+)-linalool holds a pharmacokinetic profile suitable for its application as an anesthetic in aquaculture. • This study describes for the first time the pharmacokinetics of S -(+)-linalool in a fish species. • S -(+)-linalool is rapidly absorbed, distributed to the brain and eliminated in silver catfish. • The elimination kinetics of S -(+)-linalool in the brain is slower than in the plasma. [ABSTRACT FROM AUTHOR]

The effects of dietary supplementation of graded level (0, 0.25, 0.5, 1.0, and 2.0 ml/kg diet) of Citrus aurantium essential oil (EOCA) on the growth, metabolic, and oxidative parameters of silver catfish (Rhamdia quelen) were investigated in a 60‐day growth trial. Fish fed with 2.0 ml EOCA per kg exhibited significantly better growth performance than those fed the control diet. Glucose, lactate, and protein levels in liver and muscle were altered significantly by dietary addition of EOCA. Hepatic lipid peroxidation levels, measured using thiobarbituric acid reactive substance and lipid hydroperoxides assays, were reduced in animals receiving the diet containing EOCA. Superoxide dismutase activity was higher, while glutathione S‐transferase activity was lower in the liver of fish receiving 0.5, 1.0, and 2.0 ml EOCA per kg of diet than in control. The nonprotein thiols content was higher in fish receiving the EOCA‐containing diet. Thus, dietary addition of EOCA improved growth, biochemical, and antioxidant parameters in silver catfish and could be useful as dietary supplement. [ABSTRACT FROM AUTHOR]

Abstract The effect of dietary levels of citral in juvenile common snook (Centropomus undecimalis) was evaluated by determining biomarkers of oxidative stress and innate immune system, as well as liver parameters. The fish (2.75 ± 0.03 g) were fed diets containing different concentrations of citral (0, 0.44, 0.88, and 1.76 mg/kg feed) for 45 days. Results indicate that citral does not cause significant hepatic alterations; nevertheless, this monoterpenoid was able to induce lipoperoxidation in the gills in all concentrations tested. In this context, the altered activity of enzymes such as superoxide dismutase (SOD) in the liver and gills (1.76 mg per kg feed), catalase (CAT) in the liver (0.44; 0.88 mg per kg feed) and gills (all groups), and glutathione-S-transferase (GST) in the liver (0.44 mg per kg feed) and gills (1.76 mg per kg feed) occurred in response to the oxidative damage evidenced. Although dietary levels of citral did not influence the lysozyme activity, we verified that the haemolytic activity of the complement system was excessive in the lowest concentration tested and that the myeloperoxidase activity (MPO) decreased in all groups. Thus, although this monoterpenoid is a diet additive which has already been approved for consumption in other animal species, dietary supplementation with citral for common snook has not improved oxidative parameters and innate immunity of this species. Highlights • Citral modulated negatively the oxidative stress parameters. • Myeloperoxidase levels were decreased using citral as food additive. • Citral did not promote hepatotoxicity. • We do not recommend to use citral as diet additive for common snook. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the variation in essential oils yield, chemical composition and antifungal property in Ocotea lancifolia (Schott) Mez population from Brazil. The oils were obtained by hydrodistillation from the leaves and reproductive organs collected from 12 trees. The volatile composition was established by gas chromatography and the chemical variability was assessed by multivariate procedures. The fungistatic activity against the Fusarium moniliforme was evaluated as well. Higher yields from leaves oils were obtained in spring (1.03%) and summer (0.96%). By multivariate analysis, the oils were separated in two groups. Caryophyllene oxide and bicyclogermacrene were the major constituents in healthy trees (first group) and the oils obtained from damaged trees, which contained β-chenopodiol, constituted the second one. It was observed a significant higher mycelial inhibition for the leaves oils (67.5%). Overall, we identified that the stage of development of the reproductive organs and microbiological damage influenced O. lancifolia oil. [ABSTRACT FROM AUTHOR]

This study investigated the anesthetic effect of the essential oils (EOs) from the peel of Citrus x aurantium (EOCA) and Citrus x latifolia (EOCL) on silver catfish Rhamdia quelen. Fish were exposed to different concentrations of EOCA and EOCL to determine time of anesthesia induction and recovery. Induction of anesthesia was observed in all fish exposed to 400, 600 or 800 μL L−1 EOCA and 300, 400 or 500 μL L−1 EOCL. Another group of fish were exposed for 8 h to 50, 100, or 200 μL L−1 of either EOs. Overall, fish exposed to ethanol and both EOs presented higher ventilatory frequencies (VF) than the control group throughout the 8 h of exposure. Net ion (Na+, K+ and Cl-) effluxes and ammonia excretion were significantly lower in fish exposed to 50, 100 or 200 μL L−1 of either EOs compared to control fish. Mortality was 37% in fish exposed to 200 μL L−1 of either EOs after 8 h. These findings suggest that EOCA and EOCL are useful anesthetics and sedatives for Rhamdia quelen, but their usefulness as alternatives to reduce stress in fish transportation at the lower concentrations tested (50-100 μL L−1) deserves further study. [ABSTRACT FROM AUTHOR]

This study evaluated whether anesthesia with essential oil (EO) of Lippia alba (300 mg L-1 for 4 min) prior to electronarcosis (128 V m-1 × 300 Hz for 5 s) or hypothermia (ice/water slurry) could delay fish spoilage during chilled storage of whole fish. Silver catfish (Rhamdia quelen) were subjected to two different pre-stunning treatments (water or anesthesia with EO of L. alba) followed by two different stunning procedures (hypothermia or electrical stunning), yielding four groups (n = 32/group): water (control) + hypothermia, water (control) + electrical stunning, EO of L. alba + hypothermia, and EO of L. alba + electrical stunning. After stunning, fish were slaughtered by percussion and stored in ice. Preslaughter anesthesia with the EO of L. alba extended fish shelf life by delaying the loss of freshness (nucleotide degradation), growth of Enterobacteriaceae, and fish deterioration (sensory evaluation). Such preservative effect was most remarkable for fish that were subsequently submitted to electrical stunning, as they had the lowest demerit scores and greatest shelf life in the sensory evaluation. Our results showed that preslaughter anesthesia with EO of L. alba followed by electrical stunning can delay the loss of freshness and extend fish shelf life during chilled storage. [ABSTRACT FROM AUTHOR]

Lippia alba and Aloysia triphylla essential oils (EOs) are known to contain anesthetic properties. The majority of conventional anesthetics applied to fish cause aversive behavior in these animals. Therefore, questions arise whether EOs from L. alba and A. triphylla are also aversive and if they alter anxioly-like behaviors. To answer these questions, jundiá ( Rhamdia quelen ) and zebrafish ( Danio rerio ) were studied with the preference test using 50% of the anesthetic concentration of L. alba (corresponding to 150 μL L − 1 ) and A. triphylla (corresponding to 150 μL L − 1 ) EOs and the novel tank test immediately after exposure. Cortisol analysis was also performed. We show that EOs from L. alba and A. triphylla have an anxiolytic effect on zebrafish and catfish without altering locomotor patterns or inducing aversive behavior. To the best of our knowledge, this was the first time that preference tests were applied for natural anesthetics from plant extracts. [ABSTRACT FROM AUTHOR]

The Lophiosilurus alexandri is an important species to the Brazilian aquaculture. Moreover, the studies about the effects of essential oil (EO) of Aloysia triphylla in fish are almost absent. Thus, the aims of this study were: 1) to investigate the anesthetic effect of the EO of A . triphylla and, 2) if this EO improves the physiological parameters of L . alexandri after transport. The experiment was divided in three steps: 1) the anesthesia induction with the EO of A . triphylla (in μL/L): 25, 50, 100, 200, or 400; 2) transport for 4 h with the fish separated into three groups: control and two EO concentrations of A . triphylla (in μL/L): 12.5 and 25; and, 3) determination of the ventilatory frequency (VF) in fish exposed to this EO at 12.5 or 25 μL/L. The results showed that the increasing concentration of A . triphylla EO proportionally decreased the time required for sedation and anesthesia induction and increased recovery time. After transport, some alterations in water and blood parameters were observed independently of the treatment and lower VF was found in fish exposed to 25 μL/L of A . triphylla EO. Taken together these results indicated that this EO decreased fish metabolism. Finally, A . triphylla EO was an efficient anesthetic in L . alexandri , mainly at 400 μL/L and, both EO concentrations used in the transport contributed to improve water and physiological parameters. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify and quantify the chemical constituents, as well as the antimicrobial, antibiofilm and synergistic activity with florfenicol of essential oils of Aloysia triphylla (EOAT) and Lippia alba (EOLA) against Aeromonas spp. The antimicrobial activity of EOAT and EOLA was verified by the minimum bactericidal concentration (MBC) and the action against biofilm forming and consolidated biofilm. The synergistic activity of EOAT and EOLA with florfenicol was performed by the checkerboard technique. The main components of EOAT were α-citral (39.91%), E-carveol (25.36%) and limonene (21.52%), while that of EOLA was linalool (81.64%). Aeromonas spp. isolates showed sensitivity to both essential oils with MBC between 195.3 and 3125.0 μL/mL. Two isolates were classified as non-producing, three as moderate and 16 as weak biofilm producers. The EOAT and EOLA interfered in the biofilm formation, from moderate to weak producers, but did not cause any interference in the consolidated biofilm. The EOAT and EOLA combined with florfenicol showed synergistic effect and reduced MBC. The EOAT and EOLA have potential for application as antimicrobial agents, as they interfere in the initial formation of biofilm and when combined with florfenicol, present a synergic effect with a reduction in the minimum dose of the antibiotic. [ABSTRACT FROM AUTHOR]

The goal of this study was to investigate the sedative and anesthetic properties of essential oils (EOs) in map treefrog tadpoles (Hypsiboas geographicus) and to determine the sedation and deep anesthesia induction times as well as the recovery time. The tadpoles were exposed to one of the EOs from three plant species: Aniba rosaeodora (EOAR - 25, 50, 100 or 200μL L-1), Lippia origanoides (EOLO - 13, 25, 50, 100 or 200μL L-1), and Lippia alba (either chemotype citral [EOL-C - 25, 50, 100 or 200μL L-1] or linalool [EOL-L - 50, 75, 100 or 200μL L-1]) (n = 8 per replicate). The tadpoles exposed to 25 and 50μL L-1 EOL-C and EOL-L, respectively, were not anesthetized within 30min (the maximum time of observation), and those exposed to 200μL L-1 EOLO did not recover within 30min. Sedation, deep anesthesia and recovery times showed a concentration-dependent relationship for all EOs tested, with the exception of the recovery with EOLO. The results allowed concluding that all investigated EOs can be used to anesthetize tadpoles of H. geographicus, but the use of EOLO must not exceed 100μL L-1. [ABSTRACT FROM AUTHOR]

The effects of anesthesia with essential oil (EO) of L. alba prior to electrical stunning or hypothermia were evaluated on the stability of silver catfish fillets during frozen storage. Electrically stunned fish had the greatest increase in lipid oxidation along the storage and previous anesthesia with EO potentialized this effect. Fish stunned by hypothermia with no previous anesthesia had higher lipid oxidation in the flesh immediately after slaughtering, which probably contributed to accelerate protein oxidation along the storage. Fish stunned by hypothermia had the highest springiness value by the end of storage and the highest changes in instrumental color along the storage, whereas electrically stunned fish had delayed protein oxidation and smaller color and texture changes during frozen storage. Thus, hypothermia induced greatest changes in physico-chemical markers and previous anesthesia with the EO of L. alba did not prevent these changes and did potentialize lipid oxidation induced by electrical stunning. Practical applications There is a growing interest for natural anesthetics in commercial aquaculture and essential oils have been lately used with this purpose for fish husbandry and management. The use of natural anesthetics in pre-slaughter steps, however, has been scarcely investigated. Stressful procedures during pre-slaughter and slaughter steps can adversely affect fish flesh properties and the association of anesthetics with other stunning or killing methods could be an alternative to reduce fish stress and assure flesh quality. Our study, however, revealed that fillet stability during frozen storage is not improved by fish anesthesia with essential oil prior to hypothermia or electrical stunning. In addition, we also revealed that electrical stunning yielded greater fillet stability during frozen storage compared with hypothermia. These results are relevant in the search of humane fish stunning methods that provide the greatest flesh quality and stability. [ABSTRACT FROM AUTHOR]

(+)-Dehydrofukinone (DHF), isolated from Nectandra grandiflora ( Lauraceae ) essential oil, induces sedation and anesthesia by modulation of GABAa receptors. However, no study has addressed whether DHF modulates other cellular events involved in the control of cellular excitability, such as seizure behavior. Therefore, the aim of the present study was to investigate the effect of DHF on cellular excitability and seizure behavior in mice. For this purpose, we used isolated nerve terminals (synaptosomes) to examine the effect of DHF on the plasma membrane potential, the involvement of GABAa receptors and the downstream activation of Ca 2 + mobilization. Finally, we performed an in vivo assay in order to verify whether DHF could impact on seizures induced by pentylenetetrazole (PTZ) in mice. The results showed that DHF induced a GABA-dependent sustained hyperpolarization, sensitive to flumazenil and absent in low-[Cl − ] medium. Additionally, (1–100 μM) DHF decreased KCl-evoked calcium mobilization over time in a concentration-dependent manner and this effect was prevented by flumazenil. DHF increased the latency to myoclonic jerks (10 mg/kg), delayed the onset of generalized tonic-clonic seizures (10, 30 and 100 mg/kg), and these effects were also blocked by the pretreatment with flumazenil. Our data indicate that DHF has anticonvulsant properties and the molecular target underlying this effect is likely to be the facilitation of GABAergic neuronal inhibition. The present study highlights the therapeutic potential of the natural compound DHF as a suppressor of neuronal excitability. [ABSTRACT FROM AUTHOR]

This study evaluated the potential relaxing and/or molluscicidal effects of eugenol and essential oils of Origanum majorana, Ocimum americanum, Hesperozygis ringens, and Piper gaudichaudianum in the gastropod Pomacea canaliculata. Compounds were tested at concentrations of 100, 250, 500, and 750μL L-1 to evaluate the relaxing effects. In the second experiment, animals were exposed to 10, 25, and 50μL L-1 of essential oils of H. ringens and P. gaudichaudianum for a period of 24h for the evaluation of molluscicidal effects. Eugenol and essential oils of O. majorana and O. americanum showed relaxing effects at ≥250μL L-1, but the essential oils of H. ringens and P. gaudichaudianum did not promote relaxing or molluscicidal effects within the times and concentrations studied. Therefore, only eugenol and the essential oils of O. majorana and O. americanum can be used for relaxation purposes in P. canaliculata. [ABSTRACT FROM AUTHOR]

The optimum concentration of anaesthetic used to facilitate fish handling can be determined based on induction and recovery time, among other factors. This study aimed to evaluate the effectiveness of the essential oil of Aloysia triphylla ( EOAT) as an anaesthetic in the handling of Nile tilapia juveniles. Nile tilapias exemplars were immersed at 0 (control group), 10, 20, 30, 40, 80, 150, 300 and 450 μL L−1 EOAT to evaluate sedation, anaesthesia and recovery time. The stress response was evaluated by the determination of plasma glucose, cortisol, lactate and paraoxonase levels in anaesthetized (300 μL L−1 EOAT) and non-anaesthetized fish. Fillets from both groups were evaluated for organoleptic characteristics (taste and odour). Concentrations of 80-450 μL L−1 EOAT were effective in inducing anaesthesia. There was a significant reduction in plasma cortisol levels one hour after handling in individuals anaesthetized with 300 μL L−1 EOAT compared to the control group. Tasters did not detect differences in fillet taste and odour between fish exposed and not exposed to EOAT. A concentration of 300 μL L−1 EOAT is recommended for handling Nile tilapia because it presents good anaesthetic induction and recovery times, causes a reduction in plasma cortisol levels one hour after handling and does not affect the taste or odour of the fillets. [ABSTRACT FROM AUTHOR]

This study evaluated the allelopathic effect of theHesperozygis ringensessential oil using dicotyledonous and monocotyledonous seeds which are classified as weeds [Bidens pilosaandLolium multiflorum], bioindicators [Lactuca sativaandAvena strigosa] and crops [Glycine maxandOryza sativa]. The essential oil from the leaves was extracted and analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. The extractive was diluted in ethanol, Tween 20 and water, and then tested at concentrations of 0.25, 0.50, 1.00, 2.50, and 5.00% (v/v). Water and the highest concentration of the solvents were used as control groups. The analyzed variables were germination, emergence velocity index, roots and shoot lengths and total seedlings length. Pulegone was the major essential oil compound representing 82.02% of the composition. Considering dicot seeds, the highest concentration of the extractive completely inhibited the germination ofBidens pilosawithout affecting the germination ofLactuca sativaandGlycine max. On monocots, the highest essential oil concentration affected the germination ofLolium multiflorumandAvena strigosawithout affecting theOryza sativaone. The results indicate that the extractive has the potential to control weeds because they were more affected than the crops. [ABSTRACT FROM PUBLISHER]

Ocimum gratissimum L. (known for its relaxant/sedative effects and antimicrobial properties) and Hesperozygis ringens (Benth.) Epling (known for its anti-parasitic properties) are two plants belonging to the family Lamiaceae. Currently, studies have demonstrated that the essential oils (EO) of these two plants present anesthetic and sedative activity in fish, as well as antimicrobial and antiparasitic properties against different fish pathogens. Larvicidal activity against insect larvae (fish predators) was also reported for both EOs. This study evaluated the toxicity of the O. gratissimum (OG) and H. ringens (HR) EOs in the freshwater zooplankton Daphnia pulex and their activity against different fish pathogens (bacteria and a monogenean parasite) isolated from silver catfish ( Rhamdia quelen ). The in vivo antioxidant activity of OG EO also was assessed in different tissues of this species. In addition, results from studies related to the application of both EOs in aquaculture were reviewed and summarized. The acute toxicity test in D. pulex determined EOs lethal concentration (LC50s – 24 h) to be 37.8 mg L −1 for OG EO and 61.5 mg L −1 for HR EO. Both EOs showed moderate activity against the bacteria Aeromonas hydrophila and Aeromonas veronii (MIC 400–800 μg mL −1 ) and weak activity against Citrobacter freundii and Raoltella ornithinolytica . The EOs also showed significant antiparasitic activity against the monogenean parasite Gyrodactylus sp. OG EO added to the water prevented the lipid peroxidation and increased the antioxidant status of the evaluated fish tissues. These plant-based products appear as sustainable and effective alternatives for conventional drugs and/or chemicals for disease control and prophylaxis in aquaculture. [ABSTRACT FROM AUTHOR]

This study aimed to examine the action of the essential oil of Lippia alba (EOLA) in the stress response for transport of Nile tilapia Oreochromis niloticus. The fish were transported into three treatments (in triplicate): control, 10 and 20 μL L-1 EOLA, with loading density of 15 fish/plastic bags for 8h. Plasma glucose levels were significantly decreased in fish exposed to 20μL L-1 EOLA in comparison with the control group and fish exposed to 10μL L-1 EOLA, but the plasma cortisol, lactate and paraoxonase levels were similar. Un-ionized ammonia and ventilatory rate demonstrated a significant reduction in the treatments with the use of EOLA. In conclusion the use of 20μL L-1 EOLA is indicated for Nile tilapia transport. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the anaesthetic activities of the extractives of Nectandra grandiflora and Spilanthes acmella in juvenile tambaqui fish, Colossoma macropomum as well as to investigate their effects on oxidative stress status of fish submitted to transport in hyperoxia. Fish were placed in aquaria containing five different concentrations of essential oil (EO) of N. grandiflora (25; 50; 100; 200; and 300 μL L − 1 ) or waxy extract of S. acmella (5; 10; 15; 20; and 25 mg L − 1 ), and the times of anaesthetic induction and recovery were determined by concentration-response trials. Fish transported inside plastic bags in hyperoxic conditions for 2, 6 and 10 h with or without anaesthetics were investigated for the occurrence of oxidative stress through the assessment of total antioxidant capacity against peroxyl radicals (ACAP), glutathione S-transferase (GST) activity and lipid peroxidation levels (TBARS) in muscle, gills, liver and brain. Both extractives of S. acmella and N. grandiflora induced deep anaesthesia in juvenile C. macropomum . Although transient changes occurred in ACAP and GST activity after transport, irrespective of transport time or anaesthetic used, antioxidant components in these extractives reduced or maintained lipid peroxidation within basal levels in the assessed organs. The use of 10 mg L − 1 of extract of S. acmella was suitable to induce fast anaesthesia (< 3 min) and safe recovery (< 5 min). Sedation concentrations at 1 mg L − 1 and 30 μL L − 1 of the extractives of S. acmella and N. grandiflora respectively, enhanced protection against oxidative damage mainly in muscle and gills of juvenile tambaqui and therefore have the potential to be used as chemoprotectants for transport purposes. Statement of relevance This study presents novel products to be used as anaesthetics/sedatives for fish. [ABSTRACT FROM AUTHOR]

This study is designed to evaluate the physicochemical properties and the decay resistance of leaf extracts obtained from a native Brazilian tree Ocotea lancifolia . Ethanol was used to obtain crude extract from milled leaves, which was further partitioned with ethyl acetate and butanol achieving two phenolic-rich fractions. Furthermore, wood veneers were impregnated with crude extract and its fractions (at 1 and 4%), and evaluated against two wood-destroying fungi. Firstly, Fourier transform infrared and thermogravimetric analysis confirmed chemical differences on structure, stability and purity of the evaluated extract samples. Crude extract presented lower total phenolic content (178 mg GAE/g dried sample) and lower antioxidant activity than its fractions. Moreover, the fractions showed 360–405 mg GAE/g dried sample and a high scavenging effect (IC 50 < 0.75 mg/mL). Chromatographic analysis revealed the presence of quercetin-derived monoglucosides in all samples, such as quercetin-3- O -rhamnoside (∼20–22% in crude extract and ethyl acetate fraction) and quercetin-3- O -glucoside in butanolic fraction (20.71%). Crude extract and ethyl acetate fraction at 4% were the most effective treatments to reduce the action of two wood-rot fungi (mass loss < 8%). Overall, leaf extracts from O. lancifolia can provide a renewable source of antioxidants and eco-friendly wood preservatives. [ABSTRACT FROM AUTHOR]