Oxidative responses in small juveniles of Colossoma macropomum anesthetized and sedated with Ocimum gratissimum L. essential oil.

This study evaluated the use of essential oil of Ocimum gratissimum (EOOG) for anesthesia and in transport of Colossoma macropomum. Experiment 1, Test 1, anesthesia induction and recovery times were determined using different EOOG concentrations (0, 20, 50, 100, 200, 300 mg L-1), with two size classes: Juveniles I (0.86 g) and Juveniles II (11.46 g) (independent tests in a completely randomized design). Based on the results of Test 1, in Test 2 Juveniles II were exposed to EOOG concentrations: 0, 20, 100 mg L-1. Tissue samples were collected immediately after induction and 1 h post-recovery, to assess oxidative status variables. Experiment 2, Juveniles I (0.91 g) and Juveniles II (14.76 g) were submitted to transport in water with different concentrations of EOOG (0, 5, 10 mg L-1) (independent tests in a completely randomized design). The effects on oxidative status variables were evaluated. Concentrations between 50 and 200 mg L-1 EOOG can be indicated for Juveniles I, while concentrations between 50 and 100 mg L-1 EOOG for Juveniles II. The concentration of 100 mg L-1 EOOG was able to prevent oxidative damage in the liver. In Experiment 2, the concentrations of 5 and 10 mg L-1 EOOG added to the transport water caused sedation for both studied size classes of juveniles and did not cause oscillations in water quality variables nor any mortality. The concentration of 10 mg L-1 EOOG improved the oxidative status. It can be concluded that EOOG can be used for anesthesia and transport of C. macropomum.

Hematological, biochemical and oxidative responses induced by thermal shock in juvenile Tambaqui (Colossoma macropomum) and its hybrid Tambatinga (Colossoma macropomum x Piaractus brachypomus).

The effects of thermal shock on hematological, biochemical and antioxidant responses were evaluated in liver tissue of juvenile tambaqui (Colossoma macropomum) and tambatinga (♀ C. macropomum × â™‚ Piaractus brachypomus). Forty juveniles of tambaqui and 40 juveniles of tambatinga, of the same age and with an initial weight of 23.3 ± 6.7 g, were randomly distributed in eight 28L circular tanks. A tank (n = 10 fish) of tambaqui and a tank (n = 10 fish) of tambatinga were then used to obtain basal data. The other animals were subjected to thermal shock with sudden temperature reduction from 28 to 18 ºC. Blood and tissue were then collected after 1, 6 and 24 h from the onset of thermal shock. No mortality was observed during the experimental period. Thermal shock increased triglyceride levels after 24 h of stress for tambaqui and reduced values for tambatinga. There was an effect on plasma glucose only for fish group (P < 0.0001) and collection time (P < 0.0001) with a peak observed for the hybrid after 6 h. The interaction of factors for SOD indicated greater activity for tambatinga at the 6 h collection and lower at basal and 1 h collections. There was an interaction for CAT (P = 0.0020) with less activity for tambatinga at 1 h. However, thermal shock and hybridization did not influence GST and TBARS levels in liver tissue. Therefore, the results suggest that the hybrid, tambatinga, is more efficient at promoting adjustments of biochemical responses and antioxidant enzymes during thermal shock.

Physiological responses to long fasting followed by refeeding in juveniles of pirapitinga, Piaractus brachypomus

ABSTRACT For many fish species, prolonged fasting is part of their life cycle, as there are seasonal fluctuations in the quantity and quality of food available in their natural habitat. These animals use endogenous reserves during periods of food scarcity and recover when resources become available again. We evaluated the effect of a prolonged fasting period on indicators of body reserve use, growth performance and intestinal integrity of the Amazonian serrasalmid Piaractus brachypomus. We distributed 66 juveniles (68.6 ± 2.2 g) in 11 tanks. The treatment consisted of 30 days fasting followed by 45 days refeeding and the control of 75 days normal feeding with 5 replicates (one tank with six fish). The six individuals in the 11th tank were used for baseline measurements. Blood parameters, muscle lipid concentration, hepatosomatic and mesenteric fat indices, somatic growth parameters and intestinal villi morphology were measured every 15 days. Glucose, triglycerides, cholesterol, total protein, the mesenteric fat and hepatosomatic indices, weight gain, specific growth rate, condition factor and total biomass decreased significantly during fasting compared to the control, but all except body condition recovered during refeeding. The length and perimeter of the intestinal villi was significantly lower during fasting compared to the control. The feeding protocol allowed P. brachypomus to mobilize part of their body reserves during fasting, however, in general, refeeding was sufficient to restore their body needs and growth performance compatible with that of continuously fed animals.

RESUMO Muitas espécies de peixe suportam jejum prolongado como parte do seu ciclo de vida, devido a flutuações na quantidade e qualidade de alimentos disponíveis em seu habitat natural. Esses animais utilizam reservas endógenas durante períodos de escassez de alimentos e se recuperam quando voltam a estar disponíveis. Avaliamos o efeito de jejum prolongado sobre indicadores de uso de reservas corporais, desempenho e integridade intestinal no serrasalmídeo amazônico Piaractus brachypomus. Distribuímos 66 juvenis (68,6 ± 2,2 g) em 11 tanques. O tratamento consistiu em 30 dias de jejum seguidos de 45 dias de realimentação, e o controle de 75 dias de alimentação contínua, com 5 repetições (um tanque com seis peixes). Os seis indivíduos do 11º tanque foram usados para medidas basais. Parâmetros sanguíneos, concentração de lipídios musculares, índices de gordura hepatossomática e mesentérica, parâmetros de crescimento somático e morfologia das vilosidades intestinais foram medidos a cada 15 dias. Glicose, triglicerídeos, colesterol, proteína total, índices hepatossomático e de gordura mesentérica, ganho em peso, taxa de crescimento específico, fator de condição e biomassa total diminuíram significativamente durante o jejum em comparação com o controle, mas todos, exceto a condição corporal, recuperaram-se durante a realimentação. O comprimento e o perímetro das vilosidades intestinais foram significativamente menores durante o jejum em comparação com o controle. O protocolo de alimentação permitiu que P. brachypomus mobilizasse parte de suas reservas corporais durante o jejum, porém, em geral, a realimentação foi suficiente para repor suas necessidades corporais e o desempenho compatível com o de animais alimentados continuamente.

Hesperozygis ringens essential oil as an anesthetic for Colossoma macropomum during biometric handling / Óleo essencial de Hesperozygis ringens como anestésico para Colossoma macropomum durante manipulação biométrica

This study evaluated the effectiveness of the essential oil of Hesperozygisringens (EOHR) for anesthesia of Colossomamacropomum 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.

Este estudo avaliou a eficiência do óleo essencial de Hesperozygis ringens (EOHR) para anestesia de Colossoma macropomum, documentando as respostas hematológicas e bioquímicas do sangue após o manuseio biométrico. No experimento 1, juvenis (14,12 ± 3,53 g) foram expostos a diferentes concentrações de EOHR: 0 (controle), 75, 150, 300 e 450 µL L-1 (n = 10 peixes para cada concentração), para determinar os tempos de indução e recuperação da anestesia, bem como seus efeitos na frequência ventilatória (VF). Com base nesses resultados, o experimento 2 avaliou os efeitos de 0 (controle), 75 (com tempos de indução e recuperação fora do recomendado para anestesia de peixes) e 150 µL L-1 EOHR (dentro dos tempos recomendados) sobre variáveis hematológicas e bioquímicas de juvenis (20,52 ± 3,47 g) após a anestesia e após 24h de recuperação (n = 6 peixes para cada concentração e tempo de coleta). A sobrevivência foi de 100%. O tempo de indução mostrou efeito quadrático da concentração de EOHR. O tempo de recuperação não diferiu entre as concentrações de EOHR. Concentrações entre 150 e 450 µL L-1 EOHR causaram rápida indução (< 3 min) e recuperação (< 5 min). As concentrações de EOHR afetaram a VF. A concentração de 150 µL L-1 de EOHR teve pouca influência nos parâmetros hematológicos e bioquímicos de C. macropomum de 20 g.

Anesthetic and sedative efficacy of essential oil of Hesperozygis ringens and the physiological responses of Oreochromis niloticus after biometric handling and simulated transport.

This study aimed to evaluate different concentrations of the essential oil of Hesperozygis ringens (EOHR) and its effects on anesthesia and transport of Oreochromis niloticus. Experiment I evaluated the concentrations of 0, 150, 300, 450, and 600 µL L-1 EOHR for times of induction and recovery from anesthesia and ventilatory frequency (VF) of O. niloticus (26 g), with 10 repetitions each in a completely randomized design. Based on the results of Experiment I, Experiment II submitted fish (25 g) to three treatments-control (clean water), ethanol (5 mL ethyl alcohol), and 600 µL L-1 EOHR-and then handling for biometry. Blood was collected 1 and 24 h after exposure and handling to analyze hematological and biochemical parameters in a completely randomized design in a factorial arrangement (3 × 2). Experiment III submitted fish (35 g) to simulated transport (4.5 h) with 0, 10, or 20 µL L-1 EOHR and determined the effects on blood variables. Concentrations of 450 and 600 µL L-1 EOHR provoked deep anesthesia in juvenile O. niloticus and provided induction and recovery times within the limits considered ideal for fish. However, this essential oil was not able to attenuate the effects of stress caused by biometric handling. EOHR was able to attenuate the effects of stress from simulated transport, with 10 µL L-1 EOHR being responsible for causing a decrease in protein, triglycerides, and cholesterol values immediately after transport of O. niloticus.

Lophiosilurus alexandri, a sedentary bottom fish, adjusts its physiological parameters to survive in hypoxia condition.

We investigated blood gas, hematological and biochemical parameters, and gill morphology of Lophiosilurus alexandri juveniles submitted to hypoxia for 48 h, followed by recovery for 48 h. A total of 48 juveniles (360.0 ± 141.6 g) were distributed among eight tanks (120 L) and subjected to hypoxia condition (water with dissolved oxygen at 2.12 ± 0.90 mg L-1) or normoxia (at 5.60 ± 0.31 mg L-1). Blood gas values (pH, PvCO2, PvO2, sO2, HCO3-, stHCO3-, and base excess) in hypoxia were significantly different from normoxia, while for lactate and the electrolytes (K+, Na+, Cl-, and Ca2+) there was no significant change among treatments. The erythrocytes differed significantly between normoxia and hypoxia at 72 h (24 h of recovery), while for hemoglobin and hematocrit there were no significant differences. There was a significant difference in glucose, triglycerides, and cholesterol for both normoxia and hypoxia, while plasma protein remained unchanged. All gill components (epithelial cells, erythrocytes, pillar cells, mucous cells, ionocytes, undifferentiated cells, and blood capillary lumen) differed significantly between normoxia and hypoxia. A reduction in the length of the primary lamella was observed in the hypoxia and recovery treatments, when compared to normoxia. The secondary branchial lamella showed no significant difference for both treatments. Juveniles of Lophiosilurus alexandri adapted well to hypoxia for 48 h, as they were able to adjust most of their physiological variables to survive this stress condition. After 48 h of hypoxia recovery, fish showed parameters similar to animals in normoxia. Thus, the present study shows that the tolerance to hypoxia conditions of L. alexandri, together with other important beneficial characteristics of the species, such as the high meat quality and high commercial value, demonstrates its great potential for production among regional species.

Essential oil of Ocimum gratissimum (Linnaeus, 1753): efficacy for anesthesia and transport of Oreochromis niloticus.

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.

Physiological and metabolic responses in juvenile Colossoma macropomum exposed to hypoxia.

This study aimed to evaluate hematological, biochemical, and gasometric parameters of tambaqui juveniles (Colossoma macropomum) exposed to hypoxia and subsequent recovery. Six animals were subjected to normoxia (basal) treatment with dissolved oxygen (DO) 6.27 ± 0.42 mg L-1. Water flow and aeration were reduced for 3 days (hypoxia), during which DO was 0.92 ± 0.37 mg L-1. Water flow and aeration were then reestablished with DO remaining similar to basal. The treatments were as follows: normoxia (basal); 24 h after initiating hypoxia (24H); 72 h after initiating hypoxia (72H); 24 h after reestablishing normoxia (24R); 48 h after reestablishing normoxia (48R); and 96 after reestablishing normoxia (96R). The highest glucose level was recorded at 24H (P < 0.05); the highest lactate level was at 72R; and the highest blood pH was at 24H and 72H (P < 0.05). The highest concentration of PvCO2 was at 24H (P < 0.05), while at 96R it was equivalent to basal (P > 0.05). The variable PvO2 was only higher than basal at 24R (P < 0.05). Juvenile C. macropomum managed to reestablish the main stress indicators (glucose and lactate) at 96R, while the other indicators varied during the study, with homeostatic physiology being reestablished during the recovery period.