Microsatellites Associated with Growth Performance and Analysis of Resistance to Aeromonas hydrophila in Tambaqui Colossoma macropomum.

Tambaqui, Colossoma macropomum, is the main native fish species produced in Brazil, and is an important species for genetic improvement in aquaculture. In addition, breeding studies on this species can be optimized with the use of molecular markers associated with productive phenotypes. The objective of the present study was to test the performance of growth traits and resistance to the bacteria, Aeromonas hydrophila, in association with microsatellite markers in C. macropomum. In this study, three full-sib families were subjected to bacterial challenge and morphometric growth assessments. Tambaqui families subjected to the bacterial challenge differed significantly in death time and mortality rate. There was, however, no association between resistance to bacteria and microsatellite markers. In relation to growth traits, we observed a marker/phenotype association in two microsatellites. The marker in the 6b isoform x5 gene (TNCRC6b) was associated with length, whereas an anonymous marker was associated with height. The present study highlighted the evaluation of molecular markers associated with growth traits, and can serve as the basis for future marker-assisted selection (MAS) of tambaqui.

Impact of stress on Aeromonas diversity in tambaqui (Colossoma macropomum) and lectin level change towards a bacterial challenge.

Tambaqui (Colossoma macropomum) is among the most cultivated fish species in tropical countries. Stress is the main cause of disease in fish farms. The genus Aeromonas is a common causative agent of fish diseases. This work reports the identification of Aeromonas species colonizing gills of C. macropomum submitted or not to a confinement stress. We also evaluated changes in serum levels of lectins (carbohydrate-binding proteins that are components of fish immune system) in tambaqui submitted to a challenge using two isolated Aeromonas strains. Gill tissues from stressed and unstressed fishes were used to isolate Aeromonas. Then 72 Aeromonas strains were isolated, 97% being from stressed fishes. Among these, 63 were identified at species level and 6 were classified as atypical Aeromonas strains. The most prevalent species were Aeromonas bestiarum and Aeromonas caviae and their strains were used in bacterial challenges. The lectin serum levels significantly increased after 24 h of infection with A. bestiarum; however, no significant increase was found for infection with A. caviae. In conclusion, C. macropomum gills are susceptible to colonization by different Aeromonas species, mainly at confinement stressful conditions, and serum lectins may have a role in the acute immunological response towards infection by A. bestiarum.

Hematological responses of tambaqui Colossoma macropomum (Serrassalmidae) fed with diets supplemented with essential oil from Mentha piperita (Lamiaceae) and challenged with Aeromonas hydrophila / Respostas hematológicas de tambaqui Colossoma macropomum (Serrassalmidae) alimentado com dietas suplementadas com óleo essencial de Mentha piperita (Lamiaceae) e desafiados com Aeromonas hydrophila

In fish farmings, diseases can be reduced by using immunostimulants. The aim of this study was to evaluate the immunostimulant potential of Mentha piperita in tambaqui fed with 0, 0.5, 1.0 and 1.5% of oil per kg of commercial fish feed. The fish were inoculated with Aeromonas hydrophila to challenge them. Hematological and biochemical parameters were determined after 30 days of feeding and seven days after the challenge. There was no mortality and M. piperita oil did not influence fish production parameters. However, blood hemoglobin concentration (Hb) increased in the fish fed with 0.5 and 1.5% of oil per kg of diet; albumin increased in those fed with 1.0%; cholesterol increased in all groups with oil; and triglycerides increased in those fed with 0.5%. After the bacterial challenge, the fish showed decreases in Hb when fed with diet enriched with 1.5% oil per kg of diet, in mean corpuscular volume with 1.0% and in mean corpuscular hemoglobin concentration with 0 and 1.5%. Protein levels increased in groups with 0 and 1.5% of oil and albumin when fed with 0 and 1.0%; cholesterol levels increased in the control group; and high levels of triglycerides were observed in the groups with 0, 0.5 and 1.5%. Thus, M. piperita essential oil promoted hematological alterations in tambaqui and can be recommended in diets containing up to 1.0% per kg, because of the minimal physiological modifications caused. However, additional studies are necessary to obtain more information regarding to the physiological effects of this immunostimulant.

Em pisciculturas, doenças podem ser minimizadas com o uso de imunoestimulantes. O objetivo deste estudo foi avaliar o potencial imunoestimulante do óleo essencial de Mentha piperita na dieta de tambaqui com dietas contendo 0; 0,5; 1,0; 1,5% de inclusão do óleo por kg de ração comercial para peixes. Os tambaquis foram desafiados com a bactéria Aeromonas hydrophila. Hematologia e bioquímica dos tambaquis foram determinados após 30 dias de alimentação e sete dias do desafio. Não houve mortalidade dos peixes durante o experimento, sendo que o óleo não influenciou os parâmetros produtivos dos peixes. Entretanto, a concentração de hemoglobina (Hb) aumentou em peixes alimentados com 0,5 e 1,5% de óleo por kg de dieta; a albumina aumentou em 1,0%; o colesterol aumentou em todos os grupos com óleo; e triglicérides em 0,5% por kg de dieta. Após desafio bacteriano ocorreram diminuições da Hb nos peixes alimentados com 1,5% de óleo; do volume corpuscular médio com 1,0%; e da concentração de hemoglobina corpuscular média com 0 e 1,5%. Níveis aumentados de proteína nos grupos 0 e 1,5%; da albumina em 0 e 1,0%; do colesterol no controle; e dos triglicérides em 0, 0,5 e 1,5% de óleo na dieta. Assim o óleo essencial de M. piperita na dieta promoveu alterações hematológicas e pode ser recomendado seu uso em inclusões de até 1,0% por kg da dieta de tambaqui, devido às mínimas alterações fisiológicas causadas. Entretanto, estudos adicionais são necessários, de modo a obter informações sobre os efeitos fisiológicos deste imunoestimulante.

Hematological responses of tambaqui Colossoma macropomum (Serrassalmidae) fed with diets supplemented with essential oil from Mentha piperita (Lamiaceae) and challenged with Aeromonas hydrophila / Respostas hematológicas de tambaqui Colossoma macropomum (Serrassalmidae) alimentado com dietas suplementadas com óleo essencial de Mentha piperita (Lamiaceae) e desafiados com Aeromonas hydrophila

In fish farmings, diseases can be reduced by using immunostimulants. The aim of this study was to evaluate the immunostimulant potential of Mentha piperita in tambaqui fed with 0, 0.5, 1.0 and 1.5% of oil per kg of commercial fish feed. The fish were inoculated with Aeromonas hydrophila to challenge them. Hematological and biochemical parameters were determined after 30 days of feeding and seven days after the challenge. There was no mortality and M. piperita oil did not influence fish production parameters. However, blood hemoglobin concentration (Hb) increased in the fish fed with 0.5 and 1.5% of oil per kg of diet; albumin increased in those fed with 1.0%; cholesterol increased in all groups with oil; and triglycerides increased in those fed with 0.5%. After the bacterial challenge, the fish showed decreases in Hb when fed with diet enriched with 1.5% oil per kg of diet, in mean corpuscular volume with 1.0% and in mean corpuscular hemoglobin concentration with 0 and 1.5%. Protein levels increased in groups with 0 and 1.5% of oil and albumin when fed with 0 and 1.0%; cholesterol levels increased in the control group; and high levels of triglycerides were observed in the groups with 0, 0.5 and 1.5%. Thus, M. piperita essential oil promoted hematological alterations in tambaqui and can be recommended in diets containing up to 1.0% per kg, because of the minimal physiological modifications caused. However, additional studies are necessary to obtain more information regarding to the physiological effects of this immunostimulant.(AU)

Em pisciculturas, doenças podem ser minimizadas com o uso de imunoestimulantes. O objetivo deste estudo foi avaliar o potencial imunoestimulante do óleo essencial de Mentha piperita na dieta de tambaqui com dietas contendo 0; 0,5; 1,0; 1,5% de inclusão do óleo por kg de ração comercial para peixes. Os tambaquis foram desafiados com a bactéria Aeromonas hydrophila. Hematologia e bioquímica dos tambaquis foram determinados após 30 dias de alimentação e sete dias do desafio. Não houve mortalidade dos peixes durante o experimento, sendo que o óleo não influenciou os parâmetros produtivos dos peixes. Entretanto, a concentração de hemoglobina (Hb) aumentou em peixes alimentados com 0,5 e 1,5% de óleo por kg de dieta; a albumina aumentou em 1,0%; o colesterol aumentou em todos os grupos com óleo; e triglicérides em 0,5% por kg de dieta. Após desafio bacteriano ocorreram diminuições da Hb nos peixes alimentados com 1,5% de óleo; do volume corpuscular médio com 1,0%; e da concentração de hemoglobina corpuscular média com 0 e 1,5%. Níveis aumentados de proteína nos grupos 0 e 1,5%; da albumina em 0 e 1,0%; do colesterol no controle; e dos triglicérides em 0, 0,5 e 1,5% de óleo na dieta. Assim o óleo essencial de M. piperita na dieta promoveu alterações hematológicas e pode ser recomendado seu uso em inclusões de até 1,0% por kg da dieta de tambaqui, devido às mínimas alterações fisiológicas causadas. Entretanto, estudos adicionais são necessários, de modo a obter informações sobre os efeitos fisiológicos deste imunoestimulante.(AU)