RESUMOO objetivo deste trabalho foi avaliar a eficácia do anestésico natural eugenol, em diferentes concentrações, durante o processo de anestesia do ariacó (Lutjanus synagris) cultivado. Foram utilizados 108 indivíduos, divididos em três classes de tamanho: alevinos (n = 36), juvenis (n = 36), e adultos (n = 36); com pesos médios respectivos de 3,58 ± 0,63 g; 20,24 ± 5,53 g e 263,51 ± 52,20 g, para cada uma destas classes. As concentrações testadas para as três classes de tamanho foram de 25; 50 e 75 mg L-1 sendo os tempos de anestesia e de recuperação registrados com cronômetro digital. Os resultados mostraram que quanto maior a concentração eugenol utilizada menor o tempo decorrido para atingir cada estágio de anestesia, para as três classes de tamanho. O tempo total de indução anestésica foi menor que três minutos, e a melhor concentração foi 50 mg L-1, para todas as classes de tamanhos testadas. O tempo de recuperação para esta concentração de anestésico foi de 120,7 ± 36,3 s, 78,95 ± 16,52 s, 103,33 ± 22,09 s, para as classes de alevinos, juvenis e adultos, respectivamente. A utilização eugenol para a anestesia de L. synagris foi considerada eficaz, dentro dos padrões preconizados e a concentração ideal não variou com a classe de tamanho.

ABSTRACTThe aim of this study was to evaluate the effectiveness, at different concentrations, of the natural anaesthetic, eugenol, during the anaesthesia of farmed lane snapper (Lutjanus synagris). One hundred and eight individuals were used, classified into three classes by size: fry (n = 36), juvenile (n = 36), and adult (n = 36), having an average weight of 3.58 ± 0.63 g, 20.24 ± 5.53 g and 263.51 ± 52.20 g respectively. The concentrations tested for the three classes were 25, 50 and 75 mg L-1, with times for anaesthesia and recovery being recorded on a digital timer. The results showed that for the three classes of size, the higher the concentration of eugenol used, the less the time taken to reach each stage of anaesthesia. The total time for induction of anaesthesia was less than three minutes; the best concentration being 50 mg L-1 for all the classes under test. Recovery time at this concentration of the anaesthetic was 120.7 ± 36.3 s, 78.95 ± 16.52 s, 103.33 ± 22.09 s, for the classes of fry, juveniles and adults respectively. The use of eugenol as an anaesthetic in L. synagris was considered to be effective within recommended standards, with the ideal concentration not varying by class.

The Pacific white shrimp, Litopenaeus vannamei (Penaeidae), represents about 95% of all Brazilian shrimp production. The Brazilian L. vannamei foundation broodstock was made up of specimens collected from different American Pacific sites, but little information was collected on the genetic structure of the broodstock. We used the fluorescence amplified fragment length polymorphism (fAFLP) method to study the genetic diversity of L. vannamei broodstock lines 03CMF1 and 03CBF1 originally produced by breeder-shrimps imported mainly from Panama and Ecuador, although wild individuals from other localities may also have been used in producing these two lines. Our results showed a total of 93 polymorphic bands ranging from 50 to 500 bp, the mean Nei's genetic diversity calculated for the total sample was 13.4% and identity and genetic distance analyses indicated high genetic homogeneity within and between both the broodstock lineages studied which suggests that they had similar genetic structure. These results may represent an important tool for the appropriate management of L. vannamei broodstocks.