The aim of this study was to evaluate the anesthetic efficacy of tea tree oil (TTO; Melaleuca alternifolia) and its three main compounds: terpinen-4-ol, γ-terpinene, and α-terpinene, in silver ...catfish (Rhamdia quelen). We also aimed to investigate which of these compounds may be responsible for the anesthetic effect, as well as the effect of prolonged exposure on oxidative parameters. Fish were exposed to 100, 300, 500, 800, and 1000μLL−1 of TTO, and the corresponding concentrations of terpinen-4-ol, γ-terpinene, and α-terpinene in TTO; anesthesia induction time was recorded based on fish behavior. Anesthesia induction time with 300–1000μLL−1 TTO was 185–1.512s, and with terpinen-4-ol was 103–630s; for both, the recovery time was 134–673s. The monoterpenes α-terpinene and γ-terpinene were incapable of causing sedation and anesthesia in R. quelen, but presented with an antagonistic effect when used in association with terpinen-4-ol. Based on this evidence, it can be concluded that terpinen-4-ol itself caused an anesthetic effect, and therefore, can be considered the compound responsible for the anesthetic effect of TTO. Long-term (6h) exposure to TTO (25μLL−1) and terpinen-4-ol (42μLL−1) reduced thiobarbituric acid-reactive substances levels in the liver, and terpinen-4-ol (42 and 20μLL−1) reduced lipid hydroperoxide in the liver and kidney. Glutathione-S-transferase activity demonstrated an increase in the liver of silver catfish exposed to terpinen-4-ol (20 and 42μLL−1), and increased in the kidney of silver catfish exposed to TTO at concentration of 25μLL−1 compared to the control group. In summary, TTO and terpinen-4-ol may be recommended to induce faster anesthesia, and may be suitable as sedatives for transport, because they improved the antioxidant status of silver catfish.
•Essential oil of Melaleuca alternifolia (tea tree oil – TTO) can be used as anesthetic and sedative for Rhamdia quelen.•The monoterpene terpinen-4-ol, majority compound of TTO, is suitable as anesthetic and sedative for silver catfish•Terpinen-4-ol is a compound responsible for anesthetic and sedative activity of TTO.
The current study tested the hypothesis that an increase in the ionic levels (Na+, Cl-, Ca2+, Mg2+, and K+) in the gastrointestinal tract (GIT), and hepatosomatic index (HSI), gonadosomatic index ...(GSI), and Fulton’s condition factor (FCF) are associated with the reproduction period of silver catfish (Rhamdia quelen). So, we verified ionic levels of the fluid phase of the different portions of the GIT content, HSI, GSI, and FCF of silver catfish in different seasons in a dam in southern Brazil. The highest Na+ and Cl- levels in GIT were found in spring. The stomach’s Na+ and Cl- values were lower than the other segments. The K+ and Ca2+ levels in GIT were higher in winter, except in the stomach, where the values increased in summer. The highest K+ levels were reported in the anterior intestine. The highest Ca2+ levels in winter and spring were reported in the anterior and mid-intestines. In summer, the Mg2+ levels in the intestine were lower. The values of GSI and FCF were higher in winter and spring, and those of HSI were higher in winter. In conclusion, ions in the GIT and HSI, GSI, and FCF were higher in the reproduction period (winter for spring).
RESUMO: O presente estudo testou a hipótese de que um aumento nos níveis iônicos (Na+, Cl-, Ca2+, Mg2+, and K+) no conteúdo do trato gastrointestinal (CTG), bem como no índice hepatosomático (IHS), no índice gonadosomático (IGS) e no fator de condição de Fulton (FCF) estão associados com o período de reprodução de jundiá (Rhamdia quelen). Assim, nós objetivamos verificar os níveis iônicos da fase fluida das diferentes porções do CTG, bem como IHS, IGS e FCF de jundiá em diferentes estações do ano em uma barragem no sul do Brasil. Os níveis mais altos de Na+ e Cl- do CTG foram encontrados na primavera. Os valores de Na+ e Cl- do estômago foram inferiores aos outros segmentos. Os níveis de K+ e Ca2+ no CTG foram maiores no inverno, exceto no estômago, onde os valores aumentaram no verão. Os níveis mais altos de K+ foram encontrados no intestino anterior. Os níveis mais altos de Ca2+ foram encontrados no intestino anterior e médio no inverno e na primavera. No verão, os níveis de Mg2+ no intestino foram mais baixos. Os valores de IGS e FCF foram maiores no inverno e na primavera, e do IHS foram maiores no inverno. Em conclusão, íons no CTG e HSI, GSI e FCF foram maiores no período de reprodução (inverno e primavera).
In fish, stressful events initiate a hormone cascade along the hypothalamus-pituitary-interrenal and hypothalamus-sympathetic-chromaffin (HSC) axis to evoke several physiological reactions in order ...to orchestrate and maintain homeostasis. Several biotic and abiotic factors, as well as aquaculture procedures (handling, transport, or stocking density), activated stress system inducing negative effects on different physiological processes in fish (growth, reproduction, and immunity). In order to reduce these consequences, the use of essential oils (EOs) derived from plants has been the focus of aquaculture studies due to their diverse properties (e.g., anesthetic, antioxidant, and antimicrobial), which have been shown to reduce biochemical and endocrine alterations and, consequently, to improve the welfare status. Recently, several studies have shown that biogenic compounds isolated from different EOs present excellent biological activities, as well as the nanoencapsulated form of these EOs may potentiate their effects. Overall, EOs presented less side effects than synthetic compounds, but their stress-reducing efficacy is related to their chemical composition, concentration or chemotype used. In addition, their species-specific actions must be clearly established since they can act as stressors by themselves if their concentrations and chemotypes used are not suitable. For this reason, it is necessary to assess the effect of these natural compound mixtures in different fish species, from marine to freshwater, in order to find the ideal concentration range and the way for their administration to obtain the desired biological activity, without any undesired side effects. In this review, the main findings regarding the use of different EOs as stress reducers will be presented to highlight the most important issues related to their use to improve fish welfare in aquaculture.
In aquatic environments, heavy metals are produced from natural and anthropogenic sources and the degree of contamination in fish tissues depend on the pollutant type, fish species, sampling site, ...trophic level, and their mode of feeding. The heavy metal concentration (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Zn, and Pb) in the water, sediment, and liver of two fish species (Oligosarcus spp. – carnivore and Chyphocarax voga – detritivore) was analyzed at two sampling sites in the Sinos River, Brazil, during the four seasons. The highest heavy metals concentration was observed in the sediment, followed by water, and the lowest in fish. As the sediment was the major sink for pollution by metals in this river, it probably played an important role in the uptake of these metals by the detritivore species, which accumulated more metals in the liver than the carnivore species. Furthermore, the potential ecological risk was low for both sampling sites, showing the low metal contamination in this area.
► We analyzed two sampling sites with different pollution degree in the same River. ► For both sites, metal concentration was highest in the sediment, middle in water, and lower in the fish liver. ► The detritivore species presented the highest concentration for all analyzed metals. ► Potential ecological risk for single regulator indexes showed low potential ecological risk for all analyzed metals except Cd.
Creatine kinase (CK) is an enzyme that produces and uses phosphocreatine to transfer energy to maintain tissue and cellular energy homeostasis, being considered the main controller of cellular energy ...homeostasis. Its activity in plasma/serum has been commonly used to evaluate tissue damage, since CK is released into the bloodstream during damage. This review summarizes the current knowledge regarding the use of CK activity in fish, focusing on its potential as an indicator of the impairment of energetic homeostasis and tissue damage during stressful situations, such as exposure to contaminants (metals, pesticides, microplastic), hypoxia, thermal stress, and diseases (fungal, parasitic, and bacterial). Based on the data, we can conclude that tissue CK activity can be used as a suitable indicator of the impairment of energetic homeostasis in fish exposed to different aquaculture challenge conditions, while serum/plasma CK activity can be used as the first evidence of possible tissue damage, due to its release into the bloodstream.
Lactococcosis, particularly that caused by Lactococcus garvieae, is a major re-emerging bacterial disease seriously affecting the sustainability of aquaculture industry. Medicinal herbs and plants do ...not have very much in vitro antagonism and in vivo disease resistance towards lactococcosis agents in aquaculture. Most in vitro studies with herbal extractives were performed against L. garvieae with no strong antibacterial activity, but essential oils, especially those that contain thymol or carvacrol, are more effective. The differences exhibited by the bacteriostatic and bactericidal functions for a specific extractive in different studies could be due to different bacterial strains or parts of chemotypes of the same plant. Despite essential oils being shown to have the best anti-L. garvieae activity in in vitro assays, the in vivo bioassays required further study. The extracts tested under in vivo conditions presented moderate efficacy, causing a decrease in mortality in infected animals, probably because they improved immune parameters before challenging tests. This review addressed the efficacy of medicinal herbs to lactococcosis and discussed the presented gaps.
It is unknown whether the flavonoid rutin can protect the silver catfish liver in response to exposure to a known stressor, such as the prophylactic usage of the antimicrobial agent oxytetracycline. ...Thus, the current study aimed to assess the effect of rutin incorporation into the silver catfish diet formulation on oxytetracycline-induced liver oxidative stress and apoptosis. Fish were split into four groups as follows: control, rutin (1.5 g kg diet−1), oxytetracycline (0.1 g kg diet−1) and rutin+oxytetracycline (1.5 g kg diet−1 and 0.1 g kg diet−1, respectively). After two weeks of feeding with the different diets (standard, rutin-, oxytetracycline and rutin+oxytetracycline-added diets), fish were euthanized to collect the liver. Although the rutin-added diet was unable to recover glutathione peroxidase activity, ascorbic acid and reduced glutathione (GSH) levels, which were depleted due to oxytetracycline consumption, it markedly diminished the oxidized glutathione (GSSG) content, thus decreasing the GSSG to GSH ratio, an important index of oxidative stress. It also increased glutathione reductase and markedly augmented glucose-6-phosphate dehydrogenase activities, which were declined after oxytetracycline ingestion. Furthermore, the rutin-added diet reestablished superoxide dismutase and catalase activities and reduced lipid peroxidation, nitric oxide and superoxide anion levels as well, all changes resulting from oxytetracycline consumption. Finally, it also prevented oxytetracycline-induced apoptosis through increasing heat shock protein 70 and markedly decreasing high mobility group box 1 and, consequently, reducing cleaved caspase-3 protein levels. Therefore, in conclusion, the incorporation of this flavonoid to the silver catfish diet protected the liver against oxytetracycline-induced liver oxidative stress and apoptosis.
Display omitted
•Rutin diminished lipid peroxidation in liver of oxytetracycline-fed fish.•Rutin decreased oxidized to reduced glutathione ratio in oxytetracycline-fed fish.•Rutin increased glucose-6-phosphate dehydrogenase in oxytetracycline-fed fish.•Rutin reduced oxytetracycline-induced apoptosis decreasing cleaved caspase-3.
This study assessed the potential of eugenol and the essential oil of
Lippia alba
(EOLA) in providing suitable anesthetic induction and recovery times, and their consequent effects on the blood and ...respiratory physiology, as well as the gill architecture of an Amazonian freshwater stingray,
Potamotrygon wallacei
, shortly after reaching the recovery and 48 h later. Juveniles of
P. wallacei
were exposed to increasing concentrations of eugenol (75, 100, 125, and 150 µL L
−1
) and EOLA (150, 175, 200, and 225 µL L
−1
) in an immersion bath. Anesthetic induction was found to be faster with the use of eugenol compared to EOLA. On the other hand, the stingrays anesthetized with eugenol displayed a longer recovery time than those exposed to EOLA. The highest concentrations of eugenol caused moderate to severe histological changes in the gills. No significant changes were found for hematocrit and plasma energy metabolites in the stingrays anesthetized with all concentrations of both eugenol and EOLA shortly after reaching the recovery from the ansthesia, when compared to those recovered after 48 h. Investigations regarding the potential use of these natural anesthetics are unprecedented for freshwater stingray species, and 200 μL L
−1
EOLA is recommended as the most suitable anesthetic for use in juveniles of
P. wallacei
.
This study aimed to evaluate the essential oil of
Ocimum gratissimum
L. (EOOG) for anesthesia and in the transport of
Oreochromis niloticus
. Experiment I determined the time of anesthesia induction ...and recovery during anesthesia of
O. niloticus
exposed to different concentrations of EOOG (0, 30, 90, 150, and 300 mg L
−1
). Based on data from Experiment I, Experiment II evaluated the effect of 0, 30, and 90 mg L
−1
EOOG on blood parameters and oxidative stress immediately after anesthesia induction and 1 h after recovery. Experiment III evaluated the effect of 0, 5, and 10 mg L
−1
EOOG on blood variables immediately after 4.5 h of transport of juveniles. Concentrations between 90 and 150 mg L
−1
EOOG were efficient for anesthesia and recovery. The use of 90 mg L
−1
of EOOG prevented an increase in plasma glucose. Other changes in blood parameters and oxidative stress are discussed. The use of 10 mg L
−1
EOOG in transport increased plasma glucose and decreased hematocrit values immediately after transport. It is concluded that the use of 90 and 150 mg L
−1
EOOG causes anesthesia and recovery in
O. niloticus
within the time intervals considered ideal. The use of 90 mg L
−1
EOOG favored stable plasma glucose soon after anesthesia induction and 1 h after recovery, but caused changes in the antioxidant defense system by increasing hepatic and kidney ROS. The transport of 12 g
O. niloticus
for 4.5 h can be performed with concentration of 5 mg L
−1
of EOOG.
PDF
