Early ontogeny of the commercially valuable fish red-bellied pacu Piaractus brachypomus (Characiformes, Serrasalmidae) from the Amazon, Brazil.

The initial development of the red-bellied pacu Piaractus brachypomus is described using morphological, meristic and morphometric characteristics. A total of 127 individuals were analysed (47 in the yolk-sac, 35 in pre-flexion, five in flexion, 20 in post-flexion and 20 in juvenile) with standard length varying between 2.92 and 48.61 mm. The larvae are born poorly developed and have a discoidal yolk at ~6.33 mm standard length. During early ontogeny, the mouth passes from terminal to subterminal and the anal opening reaches the vertical line over the midline region of the body. There are changes in body shape from long and moderate to deep, head length from small to large, and eye diameter from moderate to large. Dendritic chromatophores were present in the ventral, dorsal and upper part of the swim bladder in the early larval stages. Rounded spots are evident all over the body in juveniles. The total number of myomeres ranges from 39 to 41 (20-23 pre-anal, 17-20 post-anal). Through the morphometric relationships, it was evidenced that the greatest changes during the initial ontogeny of P. brachypomus occur in the transition from the post-flexion stage to the juvenile period, indicating changes in behaviour, foraging and physiology.

Anesthesia of tambaqui Colossoma macropomum (Characiformes: Serrasalmidae) with the essential oils of Aniba rosaeodora and Aniba parviflora and their major compound, linalool

The aim of this study was to determine the anesthetic efficacy of the essential oils (EOs) of Aniba rosaeodora (EOAR) and Aniba parviflora (EOAP) and one of their main compounds, linalool, in two forms: synthetic and extracted from EOAR (linalool-AR) in tambaqui (Colossoma macropomum). In the first experiment, the anesthetic induction and recovery of juveniles exposed to 25- 200 µL L-1 of EOAR or 50- 300 µL L-1 of EOAP or synthetic linalool or linalool-AR was evaluated. The second experiment observed the behavioral effects of long-term exposure (12h) of these EOs and linalools (5 and 10 µL L-1). Fish exposed to 50-200 µL L-1 of EOAR and 100-300 µL L-1 of EOAP and both linalools reached deep anesthesia between 1-10 min. Induction time for all anesthesia stages decreased with the increasing concentration of the anesthetics. Linalool-AR showed lengthier time for anesthesia induction in some stages and for recovery at 100 and 200 µL L-1 in comparison to synthetic linalool. Normal equilibrium and swimming behavior was observed in fish exposed to the EOs and linalools throughout the 12 h of exposure. In conclusion, both EOs and linalools can be used as anesthetics and sedatives in tambaqui.(AU)

O objetivo deste trabalho foi determinar a eficácia anestésica dos óleos essenciais (OEs) de Aniba rosaeodora (OEAR) Aniba parviflora (OEAP) e um de seus compostos majoritários, linalol, em duas formas: sintética e extraída a partir de OEAR (linalol-AR) em tambaqui (Colossoma macropomum). No primeiro experimento avaliou-se a indução anestésica e a recuperação de juvenis expostos a 25- 200 µL L-1 de EOAR ou 50- 300 µL L-1 de EOAP ou linalol sintético ou linalol-AR. No segundo experimento observaram-se os efeitos comportamentais de uma longa exposição (12h) a estes OEs e linalois (5 e 10 µL L-1). Os peixes expostos a 50-200 µL L-1 de EOAR e 100-300 µL L-1 de OEAP e ambos os linalois alcançaram anestesia profunda entre 1-10 min. Tempo de indução a todos os estágios de anestesia diminuiu com o aumento na concentração dos anestésicos. Linalol-AR levou um maior tempo para induzir anestesia e para recuperação com 100 e 200 µL L-1 em comparação ao composto sintético. Peixes expostos aos OES e linalois por 12 h apresentaram equilíbrio e comportamento natatório normais. Em conclusão, tanto os OEs como o linalol sintético ou natural de AR podem ser usados como anestésicos e sedativos em tambaqui.(AU)

Oxidative and biochemical responses in Brycon amazonicus anesthetized and sedated with Myrcia sylvatica (G. Mey.) DC. and Curcuma longa L. essential oils.

OBJECTIVE: To investigate the effects of rapid anesthesia and long-term sedation with the essential oils (EOs) of Myrcia sylvatica (EOMS) and Curcuma longa (EOCL) on biochemical and oxidative parameters in matrinxã. STUDY DESIGN: Prospective, randomized, laboratory experiment. ANIMALS: A total of 72 matrinxã (Brycon amazonicus) adults weighing 404.8 ± 27.9 g were divided into eight groups of nine fish. METHODS: Biochemical and oxidative effects were investigated in plasma and tissues of matrinxã subjected to rapid anesthesia (5 minutes) or long-term sedation (360 minutes, simulating the practice of transport) with EOMS (200 µL L-1 and 10 µL L-1, respectively) and EOCL (500 µL L-1 and 40 µL L-1, respectively). RESULTS: Transport simulation without sedation or anesthesia increased lipid peroxidation levels in the gills and kidney of fish in the control group. Anesthesia and sedation with EOs decreased cortisol concentrations and increased lactate concentrations compared with controls. Lipid peroxidation was lower in the brain, gills, liver and kidney of sedated and anesthetized fish, than in the control group. Anesthesia with EOs increased the activity of superoxide dismutase and glutathione-S-transferase in the brain, and catalase in the liver and gills, compared with controls. Long-term sedation with EOs increased superoxide dismutase, glutathione peroxidase and glutathione reductase activities in the brain, catalase in the liver, glutathione peroxidase and glutathione reductase in the gills and superoxide dismutase in the kidney. In general, nonprotein thiols content and total reactive antioxidant potential of tissues were higher after anesthesia and sedation with EOs compared with the control group. CONCLUSIONS AND CLINICAL RELEVANCE: The concentrations of EOMS and EOCL used were effective at preventing a stress response and excess of reactive oxygen species formation. For these reasons, these substances may be recommended for use in the transportation of fish to improve survival and animal welfare.