RESUMO
The genetic variability of four Colossoma macropomum broodstocks, three from fish farms in different regions and one from the natural environment in Brazil, was analyzed using microsatellite markers. The wild progeny (n = 30) were caught in the Solimões-Amazonas River, at the varzea lakes; this location is used to mature the fish from larvae to juveniles. The three fish farms were selected according to the age of their lineages and broodstock availability: DNOCS (n = 21) is located in the Ceará State, representing the oldest lineage of cultivated tambaqui in Brazil; Balbina (n = 30) is located in the Amazonas State, representing the youngest stocks of tambaqui farmed in Brazil (approximately 15 years); and UFRPE (n = 30) is located in the Pernambuco State and is considered to be a mixed stock formed from the DNOCS and Balbina lineages. The analysis of 13 microsatellite loci indicated the occurrence of a variability reduction in the farmed populations; the UFRPE stock was the population with the highest diversity level. Low values of molecular coancestry were found in these populations. Additionally, significant differences in the RST values among the populations were detected, as was the occurrence of genetic structure. The genetic loss found in these populations may have been influenced by the founder effect. Because no breeding programs were during the entire production period and no pedigree records were kept for these broodstocks, we suggest that a wild population might be used as an important genetic resource to increase the genetic diversity of renewal stock lineages.
Assuntos
Caraciformes/genética , Variação Genética , Genética Populacional , Repetições de Microssatélites , Alelos , Animais , Aquicultura , Brasil , Cruzamento , Efeito Fundador , Análise de Sequência de DNARESUMO
O camarão marinho e a tilápia, no Estado do Ceará, são importantes commodities na aquicultura. O desenvolvimento de técnicas de cultivo possibilitou o cultivo do camarão marinho em água doce com a tilápia. O experimento foi realizado com o objetivo de obter informações sobre o policultivo do camarão marinho, Litopenaeus vannamei, com a tilápia do Nilo, Oreochromis niloticus, em tanques. O cultivo teve duração de 120 dias. Foram utilizadas pós-larvas de L. vannamei com pesos e comprimentos médios iniciais de 0,041g e 16,20mm e alevinos machos revertidos sexualmente de tilápia do Nilo, de 1,531g e de 45,27mm, respectivamente, os quais foram cultivados em diferentes densidades, em tanques com capacidade de 1 m3. O pH e a temperatura médios da água dos tanques foram de aproximadamente 8,00 e 27ºC, respectivamente. Os camarões e as tilápias foram alimentados com dieta artificial para peixes. O comprimento e o peso médio final dos animais foram de 127, 129 e 128mm e 13,3; 14,2 e 14,0g para os camarões e de 233, 222 e 236mm e 22,9; 22,1 e 24,6g para as tilápias, nos tratamentos A, B e C, respectivamente. A sobrevivência média da tilápia e do camarão foi de 83,33; 87,50 e 86,11 e 100,00; 83,33 e 100,00 para os tratamentos A, B e C, respectivamente. Os testes estatísticos não mostraram existir diferenças entre os tratamentos. Conclui-se que pós-larvas de L. vannamei podem ser cultivadas juntas com tilápia do Nilo O. niloticus em água doce.
The shrimp and tilapia cultures in Ceara are important commodities in aquaculture. The development of aquaculture techniques is making it possible to culture shrimp in freshwater with tilapia. This experiment was carried out to provide more information on the policulture of Litopenaeus vannamei marine shrimp with tilapia Oreochromis niloticus in tanks. They were cultured for 120 days. Post-larvae of L. vannamei an average initial weight and length of 0.041g and 16.20mm, and sex reverted fingerlings of O. niloticus of 1.531g and 45.27mm, respectively, were cultured in different densities, in each 1 m3 tank. The pH and temperature of the water was approximately 8.00 and 27ºC, in the tanks, respectively. The shrimps and tilapia were fed with an artificial fish diet. The final average of length and weight of the shrimp and tilapia were 127, 129 and 128mm and 13.3, 14.2 and 14.0g, and 233, 222 and 236mm and 22.9, 22.1 and 24.6g for the A, B and C treatments, respectively. The survival rate of tilapia and shrimp were 83.33, 87.50 and 86.11 and 100.00; 83.33 and 100.00 for the A, B and C treatments, respectively. The tests showed no statistically differences among the treatments. We concluded that the post-larvae of L. vannamei can be reared with tilapia O. niloticus in freshwater.
El camarón marino y la Tilapia en el estado de Ceará, son importantes commodities en la acuicultura. El desarrollo de técnicas de cultivo posibilitó el cultivo del camarón marino en agua dulce con la tilapia. El experimento fue realizado con el objetivo de obtener informaciones sobre el policultivo del camarón marino, Litopenaeus vannamei con la tilapia del Nilo, Oreochromis niloticus en estanques. El cultivo tuvo duración de120 días. Fueron utilizadas postlarvas de L.vannamei con pesos y extensión medianos iniciales de 0,041g y 16,20 mm y alevinos machos apareados sexualmente de tilapia del Nilo, O.niloticus de 1,531g y de 45,27 mm, respectivamente, donde fueron cultivadas en diferentes densidades, en estanques con capacidad de 1 m³.O pH y la temperatura mediana del agua del estanque fueron de aproximadamente 8,00 y 27ºC respectivamente. Los camarones y las tilapias fueron alimentados con dieta artificial para peces. La extensión y el peso medio final de los animales fueron de 127,129 y 128 mm y 13,3 , 14,2 y 14,0g para los camarones, y de 233, 222 y 236mm y 22,9; 22,1 y 24,6g para las tilapias, en los tratos A,B y C respectivamente. La sobrevivencia media de la tilapia y del camarón fue de 83,33, 87,50 y 86,ll y 100,00, 83,33 y 100,00 para los tratos A, B y C respectivamente. Las pruebas estadísticas no exhibieron existir diferencias entre los tratos. Se deduce que postlarvas de L.vannamei pueden ser cultivadas juntas con Tilapia del Nilo O.niloticus en agua dulce.
