The anaesthetic potential of menthol was evaluated in lambari Astyanax altiparanae by exposing fingerlings to concentrations 50, 100, 150, 200, 250 and 300 mg L À1 and measuring the induction and recovery times to deep anaesthesia, the mortality rates during and 96 h after procedure and after 6 min of continuous exposure. The effect of menthol on stress responses were evaluated by comparing glucose and cortisol levels of juveniles subjected to anaesthesia (50 mg L À1 ), stress (air exposure) or pre-anaesthesia associated to stress. All concentrations induced deep anaesthesia within 0.5 to 1 min, with recovery between 1.83 and 4.16 min, without mortality during the induction or up to 96 h after exposure. Induction time decreased and recovery time increased linearly as the menthol concentration increased. Continuous exposure to 50, 100 and 150 mg L À1 concentrations resulted in mortality rates of 0%, 20% and 80% respectively. Anaesthesia or air exposure increase blood glucose but prior anaesthesia with menthol suppressed the elevation of cortisol caused by stress. Menthol has an anaesthetic effect and attenuates the stress response in lambari and 50 mg L À1 is the most effective concentration for inducing deep anaesthesia in 1.0 min, safe for up to 6 min exposure.

No abstract

RESUMO Avaliaram-se os efeitos do extrato de maracujá veiculado na dieta (0, 50, 100 e 200mg kg -1 ) sobre o consumo de alimento, o ganho em peso e os níveis de glicose e cortisol plasmático de juvenis de tilápias do Nilo (87,0 6,6g

RESUMO Para avaliar o efeito anestésico do óleo de cravo em lambaris (Astyanax altiparanae), cinco grupos de 30 alevinos (0,6±0,1g)

No abstract

No abstract

The objective of this study was to evaluate the effects of different oil sources and alpha-lipoic acid levels on pacus performance, chemical composition of fillets and histological changes in the liver. A total of 480 pacu juveniles (3.35 ± 0.78 g), distributed in 24 experimental units (n = 20), were used. Six treatments were delineated in a completely randomized design (CRD), in a 3 x 2 factorial scheme, with three sources of oil (soybean, sesame and linseed) and two levels of alpha-lipoic acid (0 and 0.1%), with four replications. Data were evaluated statistically by analysis of variance (ANOVA) and Tukey’s test (5%). Diets containing linseed oil as the only lipid source provided better indices of final body weight and individual weight gain in pacu juveniles. Crude protein content was higher in fish fillets that fed diets without alpha-lipoic acid. Liver histology was not affected by the experimental diets. In conclusion, linseed oil improved final body weight and individual weight gain on pacus, and alpha-lipoic acid did not affect the performance of the animals, however, its absence promoted higher levels of crude protein in fish fillets.

No abstract