Effect of different concentrations of bonny-light crude oil on alanine kinase and alanine transaminase enzyme activities in Heterobranchus bidorsalis juveniles

The effect of exposing juveniles of Heterobranchus bidorsalis (Geoffroy St. Hilaire, 809) (mean weight: 15.02~c:0.14g) to different concentrations of Bonny-light crude oil (BLCO) on alanine kinase and alanine transaminase activities were studied. The exposure of the fish to 1.00, 2.00, 4.00, 8.001L-1 BLCO and a control (0.00m1 L-1) within 4 days toxicity and 42 days recovery periods indicated that the significant increases (P<0.05; P<0.01) in the serum alanine transaminase (HCAT) activities were dependent on the BLCO concentrations. The reduced SAK and (HCAK) activities noticed within the first 14 days recovery period implied that the removal of the oil pollutant probably lowered the pressure on the SAK and HCAK to participate in the metabolism of ingested carbohydrate. The significant increases in the serum alanine transminase (SAT) and the hepatic cytosolic alanine transminase (HCAT) activities in the fish corresponded with the trend shown by the SAK and HCAK activities. Generally, the increased activities of SAK, HCAK, SAT and HCAT in H. bodorsalis juveniles in this study might be due to a shift in the carbohydrate metabolism of the fish caused probably by the crude oil exposure

Effects of crude oil and the fractions on the blood haemoglobin and neutrophil concentrations in Heterobranchus bidorsalis juveniles

Studies on the effects of crude oil and its fractions on the blood haemoglobin (HB) neutrophil (NP) concentration in the blood of Heterobranchus bidorsalis juveniles were carried out. Two study periods (toxicity and recovery) and four oil types (Bonny-light crude oil (BLCO), premium motor spirit (PMS), kerosene (DPK) and lubricating engine oil (lBO) at 1.00, 2.00, 4.00 and 8.00ml were used. There were significant differences (P<0.05, p< 0.01) on the HB and NP values in blood of fish samples. The elevated values of HB levels in fish exposed to 2.00,4.00 and 8.00m1 L-1 BLCC, 2.00ml L-1 PMS and DPK; and 4.00ml L -1 LBO over the levels in the control fish were in consonance with the results of other workers. Increases in NP values in fish exposed to the four oil types (BLCO, PMS, DKP and LBO) relative to the control could be part of the immunological attempts by the fish to mobilize the body's defence mechanisms. The relatively high percent mortality and low survival of H. bidorsalis juveniles exposed to 4.00 and 8.00mlL-1 concentration of the four oil types over the other concentration implied that these concentrations were probably lethal to fish existence

Efficacy of menthol as an anesthetic for tambaqui (Colossoma macropomum, Characiformes: Characidae)

Anesthetics are important in fish culture to reduce handling stress and mortality. The objective of this work is to investigate menthol as an anesthetic for tambaqui. In the first series of tests, fish were exposed to various concentrations of menthol to evaluate induction time and stress responses. The second series examined the effect of exposure period to menthol at 150 mg/L on recovery time. The third assessed the best dosage for juveniles in larger tambaqui. The best concentration for surgical anesthesia is 150 mg/L. At this concentration the induction time is short, but their recovery time is significantly longer than that for lower concentrations. For biometry procedures, the best concentration is 100 mg/L. At this concentration the induction time is prolonged, but the recovery time is within the desired period. Recovery time for fish exposed to 150 mg/L is equal for 10, 20 or 30 minutes of exposure. The results confirmed that menthol is an adequate anesthetic for tambaqui.Os anestésicos são importantes na piscicultura para reduzir o estresse e a mortalidade no manejo. Este trabalho tem como objetivo determinar a eficácia do mentol para tambaqui durante o manejo. Na primeira série de testes, foi examinado o efeito da concentração de anestésico sobre indução à anestesia e o estresse de tambaqui. Na segunda série de testes, foi avaliada a recuperação dos peixes após a exposição a uma concentração de 150 mg/L de mentol por diferentes tempos. Na terceira série, foi avaliada se a melhor concentração encontrada para juvenil (150 mg/L) também era adequada para peixes maiores. A melhor concentração para uma anestesia cirúrgica foi 150 mg/L, pois o tempo de indução é rápido, porém a recuperação é significativamente mais demorada do que para as menores concentrações testadas. Para uma anestesia, com finalidade de biometria, a melhor concentração foi 100 mg/L. Nesta concentração o tempo de indução à anestesia é prolongado, porém o tempo de recuperação está dentro da faixa considerada adequada. O tempo de recuperação do tambaqui quando exposto a 150 mg/L é significativamente igual para 10, 20 e 30 minutos de anestesia. Os resultados obtidos mostram que o mentol é um anestésico eficiente para o tambaqui