ABSTRACT Macrobrachium rosenbergii is the freshwater shrimp species of greatest economic interest, and its reproduction has been studied for commercial purposes. This study aimed to evaluate the effect of different salinities (0, 6, and 12 mg L−1) on the embryogenesis of this species. The females were observed daily according to their reproductive behavior. Upon the first sign of spawning, when their eggs were attached to the abdomen, they were collected for egg collection and transferred to the incubators at the respectively tested salinities. The eggs were collected every five days for up to 23 days, separated according to their stage of development, histologically processed, and stained for visualization of structural changes during embryogenesis using an optical microscope. From the egg's histological images at different embryonic development stages, the egg hatching time was evaluated, the changes that occurred in the eggs during embryogenesis, the total area of the eggs, the vacuole area, and the ratio between the vacuole area and the total area of the eggs. Differences were observed in hatching time, egg size, and vacuole area and area ratio. The 6 g L−1 of salinity treatment was statistically different from the other in all parameters analyzed. Therefore, it was concluded that 6 g L−1 of salinity positively influenced embryogenesis, as it presented hatches from the 15th day of embryogenesis, demonstrating that there was a greater speed of migration of vitellogenin for the formation of the embryo, accelerating embryogenesis and hatching of M. rosenbergii.

ABSTRACT. The present study evaluated the effect of different energy levels (15.07, 15.91, 17.17, 18.00, and 19.68 kJ g−1 of diet) on isoproteic practical diets for Macrobrachium amazonicum during the nursery phase on the zootechnical performance and proximate composition of the whole body. Postlarvae with a mean weight of 0.043 ± 0.01 g were stored in 25 experimental units, at 150 animals per m2, in a completely randomized design with five treatments and five replicates. The post-larvae were evaluated at the end of the experimental period according to the pre-established performance parameters. The analysis of variance for regression (α = 0.05) allowed us to estimate that the maximum final weight was observed in the treatment with 16.74 kJ g−1. In contrast, the lowest apparent feed conversion was observed at the 16.43 kJ g−1 level. The best values were found in 17.29 and 17.50 kJ g−1, respectively, for the energy and protein retention rates. As the best fit of the equation was presented for the energy retention ratio (R2 = 0.63), which approached the treatment of 17.17 kJ g−1, this energy level is recommended in postlarvae diets.

ABSTRACT Four treatments were established to evaluate the effect of delayed first exogenous feeding and subsequent feeding periods on the development of goldfish larvae. The fasting and feeding periods were arranged as follows: T1 (0DFA:30DF), T2 (4DFA:26DF), T3 (8DFA:22DF), and T4 (12DFA:18DF), where DFA are the days of fasting and DF are the days of feeding. The larvae were kept in community tanks for each repetition, with 75 larvae per tank (3.75 larvae L−1). There was no significant difference in total length or final weight between larvae submitted to 0, 4, and 8 days of feed deprivation. However, larvae submitted to 12 DFA had higher values of the same variables than the other treatments. No significant difference in larval survival was observed between T1, T2, and T3, but T4 negatively influenced survival. Under the conditions evaluated, the point of no return was 4 DFA. Dead larvae were partly eaten in the fasting treatments. The delayed first feeding should be avoided in large-scale productions since it significantly reduces survival during cultivation. This article results from research funded by the Pescarte Environmental Education Project (PEA/IBAMA).

ABSTRACT To compare the zootechnical performance of the Brazilian native shrimp Penaeus schmitti and the exotic shrimp Penaeus vannamei, juveniles were grown under controlled conditions. Both species were simultaneously cultivated (monoculture) in separate 70 L plastic tanks at two different densities: 30 and 50 ind m-2. Also, in the other two treatments, both species were cultivated together (mixed), with and without feeding, at 30 ind m-2. During the experiment, P. vannamei generally showed a greater interest in food and voracity than P. schmitti. At harvest, for both stocking densities of monoculture treatments, the mean growth rate observed for P. vannamei was 1.0 g week-1, while P. schmitti achieved only 0.1 g week-1. The mean final weight was 10.4 ± 2.0 g; 10.7 ± 2.1 g for P. vannamei and 2.8 ± 0.3 g; 3.2 ± 0.3 g for P. schmitti, for respective densities of 50 and 30 ind m-2. In the mixed treatment with feeding, while P. vannamei reached 11.9 ± 1.4 g, P. schmitti reached only 2.6 ± 0.4 g in the same tank. The observed differences were 3.7 and 3.4 higher in favor of P. vannamei in the monoculture treatment, and up 4.5 times higher in the mixed treatment. Under strict fasting conditions, both species practiced predation/cannibalism among themselves. The results reflected the zootechnical advantages of P. vannamei, but also corroborated the negative effect that high densities and lack of natural food can exert over native species. The potential for P. schmitti cultivation and the possible impact of the escape of P. vannamei into the natural environment is discussed.

Resumo: Objetivo Este trabalho tem como objetivo registrar a ocorrência da espécie não nativa Macrobrachiun rosenbergii na bacia hidrográfica do rio Piquiri, Estado do Paraná, Brasil, um importante sistema hidrográfico Sul-Americano. Métodos As amostras foram coletadas de outubro de 2015 a junho de 2016 e de setembro de 2017 a setembro de 2018, utilizando armadilhas e equipamento elétrico de pesca (gerador de corrente alternada portátil, 2,5 kW, 400 V, 2A) no rio Piquiri e dois afluentes. Resultados 16 espécimes de M. rosenbergii foram capturados, 11 fêmeas e 5 machos. Conclusões Nossos resultados indicaram a introdução da espécie M. rosenbergii na bacia do rio Piquiri pela atividade de aquicultura. A constante inserção de novos espécimes pela aquicultura pode manter populações com elevado número de indivíduos, ocasionando potenciais danos à biodiversidade nativa.

Abstract: Aim The objective of this work is to record the occurrence of non-native species Macrobrachiun rosenbergii in water bodies of the Piquiri River basin, State of Paraná, Brazil, an important South American hydrographic system. Methods Samples were obtained from October 2015 to June 2016 and from September 2017 to September 2018, using traps and electric fishing equipment (portable alternating current generator, 2.5 kW, 400 V, 2A) in the Piquiri River and two tributaries. Results 16 M. rosenbergii specimens were caught, 11 females and 5 males. Conclusions Our results indicated the introduction of the species M. rosenbergii into the Piquiri River basin by aquaculture activity. The constant insertion of new specimens by the productive sector may, in the short term, maintain populations with large number of individuals, causing potential damage to the native biodiversity.

O objetivo deste trabalho foi avaliar o uso de probióticos na produção de pós-larvas do camarão-rosa (Farfantepenaeus brasiliensis). Utilizou-se o delineamento experimental inteiramente casualizado, com dois tratamentos - uso de probióticos (Bacillus spp.) e controle com uso de antibiótico (eritromicina) - e quatro repetições. Pós-larvas no estágio PL1 foram estocadas em cada parcela experimental (3,0 L) e cultivadas até o estágio PL10. As variáveis de qualidade de água e o desenvolvimento de bactérias do gênero Vibrio, na água de cultivo, foram monitorados ao longo do experimento. Ao final do período experimental, as pós-larvas foram avaliadas qualitativamente e quanto à sobrevivência, ao peso e ao comprimento. Nas variáveis de qualidade de água, apenas o nitrito apresentou valor significativamente maior no tratamento com antibiótico. Para as variáveis peso e comprimento final, não houve diferenças significativas entre os tratamentos. Não foram observadas diferenças significativas entre os tratamentos quanto à qualidade das pós-larvas e à concentração de Vibrio spp. na água. A utilização de antibiótico pode ser substituída pelo emprego de probióticos durante a produção de pós-larvas de F. brasiliensis.

The objective of this work was to evaluate the use of probiotics in the production of postlarvae of pink shrimp (Farfantepenaeus brasiliensis). A completely randomized experimental design was used, with two treatments - use of probiotics (Bacillus spp.), and a control using antibiotic (erythromycin) -, and four replicates. Postlarvae in the PL1 stage were stocked in each experimental unit (3.0 L) and cultured until stage PL10. Water quality variables and the development of the bacteria of the genus Vibrio, in the culture water, were monitored throughout the experiment. At the end of the experimental period, postlarvae were evaluated qualitatively and for survival, weight, and length. Regarding water quality variables, only nitrite was significantly higher in the antibiotic treatment. For the variables weight and length, there were no significant differences between treatments. No significant differences between treatments were observed in postlarvae quality and in the concentration of Vibrio spp. in the water. The use of antibiotics may be replaced by probiotics during production of F. brasiliensis postlarvae.