Acute and chronic salinity tolerance in adult siamese fighting fish, Betta splendensABSTRACT -Salinity tolerance of Betta splendens was evaluated in a complete randomized design, with six salt concentrations in the water (0; 3; 6; 9; 12 and 15 g common salt/L) with five replications (1 fish/replication). Adult female B. splendens were individually placed in aquariums in an incubation chamber at 26 ± 0.2ºC and 12-hour photoperiod. Fish were fed to satiation, once a day, with commercial diet. Feed intake and survival rate were measured every 12 hours. To evaluate the effect of acute salinity, the mean survival time and median lethal salinity-96 h were calculated, while the chronic effect (18 days) was assessed by calculating the survival salinity maximum and median lethal salinity. The mean survival time was significantly lower at 15 g/L water salinity. The median lethal salinity-96 h calculated was 11.88 g/L, the survival salinity maximum was between 6 and 7 g/L, and the median lethal salinity was 9.35 g/L. There was a significant interaction between feeding time and water salinity. Considering that the B. splendens is a freshwater species, it was concluded that this species demonstrated a high tolerance to water salinity.

-The aim of this study was to evaluate the influence of light intensity on the feed training of juvenile giant trahiras (Hoplias lacerdae). A completely randomized design with four light treatments and three replicates was used, and the following light intensities were tested: 204.9; 177.58; 54.64 and 0.00 lux. Juvenile giant trahiras (length = 3.0 ± 0.4 cm and weight = 0.5 ± 0.05 g) were stocked at 6 fish L -1 in 12 rectangular tanks (24 × 20 × 14 cm) containing six liters of water, and subjected to feed training to accept dry diets. At the end of the experiment (21 days), weight gain, length gain, survival, cannibalism, and mortality rates were evaluated. Data were subjected to regression analysis at 5% probability. Different light intensities did not affect growth, survival, mortality, or cannibalism rates in juvenile giant trahiras during the feed training.Therefore, this species can be trained to accept dry diets in the presence or absence of light.

Two experiments were performed. The first aimed to assess the tolerance of fingerlings Astyanax altiparanae to water salinity. Fish were exposed to salinity of 0, 3, 6, 9, 12 or 15 g NaCl L -1 for 96 hours. The fish mortality was 0%, in the levels of 0, 3 and 6 g L -1 ; 75% in the level of 9 g L -1 and 100% at 12 and 15 g L -1 of common salt. The second experiment aimed to assess the parameters of water quality, mortality and blood glucose during transport. For this, A. altiparanae were stored in plastic bags at 22, 30 and 37 g of fish L -1 stocking densities and salinity of 0, 3, 6 and 9 g L -1 , for. Fish showed similar mortality levels in the different salinities and stocking densities. The increase in fish density reduced the dissolved oxygen levels and salinity decreased the pH. The blood glucose levels were higher in those fish with 0 g L -1 salinity and higher stocking densities. The addition of salt to the water reduces the stress responses of A. altiparanae during transport.Transporte de Astyanax altiparanae Garutti and Britski, 2000 em água salinizada RESUMO. Foram realizados dois experimentos. O primeiro teve o objetivo de avaliar a tolerância de alevinos de Astyanax altiparanae a salinidade da água. Os peixes foram submetidos às salinidades de 0, 3, 6, 9, 12 ou 15 g de NaCl L -1 durante 96 horas. A mortalidade dos peixes foi de 0%, nos níveis de 0, 3 e 6 g L -1 ; de 75% no nível de 9 g L -1 e de 100% em 12 e 15 g L -1 de NaCl. No segundo experimento, objetivou-se avaliar os parâmetros de qualidade de água, mortalidade e a glicose sanguínea durante o transporte. Para isso, A. altiparanae foram estocados em sacos plásticos nas densidades de 22, 30 e 37 g de peixe L -1 e salinidades de 0, 3, 6 e 9 g de NaCl L -1 . A mortalidade foi semelhante nas diferentes salinidades e densidades de estocagem. O aumento da densidade de peixes reduziu o nível de oxigênio dissolvido e a salinidade da água reduziu o pH. Os níveis de glicose sanguínea foram maiores nos peixes expostos a salinidade de 0 g L -1 e nas maiores densidades de estocagem. A adição de sal na água reduz as respostas de estresse em A. altiparanae durante o transporte.Palavras-chave: densidade, estresse, glicose, oxigênio, sal comum.

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-The objective of this work was to evaluate suplemenation of vitamin C during feed training of giant trahira fingerlings. An experiment was established in a complete random design with seven treatments (0.0, 17.5, 52.5, 87.5, 122.5, 175.0 and 350.0 mg vitamin C/kg diet) and four repetitions. Giant trahira fingerlings (2.8 ± 0.2 cm) were distributed in 6-L aquaria at the density of 6 fish/L. A basal diet was formulated with 44.0% of crude protein and vitamin C and bovine heart were added in it daily. After 20 days, biometry of fish for evaluation of weight and length gains, rates of survival and cannibalism and uniformity of final length and for macroscopic observations of clinical signs of deficiency or excess of vitamin was carried out. After biometry evaluation, ten fish from each tested diet were collected for analysis of the fatty acid profile which was compared to profile of fish at the same life stage fed forage fish collected from breeding fishponds. Data on growth performance and fatty acid profiles were submitted to analyses of polynomial regression and uniformity of the final length was evaluated by the Bartlett test. There was a significant difference only for uniformity in final length and fatty acid profile of the carcass. Supplementation with 52.5 mg vitamin C/kg diet provided a greater uniformity of the final length of the fish. Fish from breeding fishponds presented lower concentration of PUFA (polyunsaturated fatty acids) and higher concentration of saturated fatty acids compared to fish trained to accept dry diets. com 44,0% proteína bruta, e diariamente foi adicionada vitamina C e coração bovino. Após 20 dias, realizou-se biometria dos peixes para avaliação do ganho de peso e do comprimento, das taxas de sobrevivência e canibalismo e da uniformidade do comprimento final e para observações macroscópicas de sinais clínicos de deficiência ou excesso da vitamina. Após a biometria, dez peixes de cada dieta testada foram coletados para análise do perfil de ácidos graxos e este perfil foi comparado ao perfil de peixes, na mesma fase de vida, alimentados com peixes forrageiros coletados de viveiros de criação. Os dados de desempenho produtivo e perfil de ácidos graxos foram submetidos a análise de regressão polinomial e a uniformidade do comprimento final avaliada pelo teste de Bartlett. Houve diferença significativa apenas para a uniformidade em comprimento final e perfil de ácidos graxos da carcaça. A suplementação com 52,5 mg de vitamina C/kg de ração proporcionou maior uniformidade do comprimento final dos peixes. Os peixes dos viveiros de criação apresentaram menor concentração de PUFA (polyunsaturated fatty acids) e maior de ácidos graxos saturados em comparação aos peixes condicionados a aceitar dietas secas.Palavras-chave: canibalismo, Hoplias lacerdae, peixes carnívoros, perfil lipídico, uniformidade em comprimento Revista Brasileira de Zootecnia