RESUMEN
ABSTRACT: Different technologies have been developed to improve the performance of Litopenaeus vannamei in low salinity, mainly in super-intensive systems like recirculation and BFT (Biofloc Technology System) systems. However, there is an accumulation of toxic nitrogenous compounds to the shrimps such as nitrate, that at high concentrations and depending on the salinity of the culture water can be lethal. Acute toxicity tests allow to analyze the relationship between the compound and other abiotic or biotic variables. The aim of this research was to determine the acute toxicity and safety level of nitrate (N-NO3 -) for juveniles of L. vannamei at salinities of 5 and 10g.L-1. For salinity of 5g.L-1, a control and 5 treatments were tested, with nitrate concentrations of 100, 500, 1500, 2500 and 3500mg.L-1.For salinity of 10mg.L-1, a 4500mg.L-1nitrate concentration was added. Juveniles were exposed to concentrations during 24, 48, 72, 96 hours in static system. The Mean Lethal Concentration (LCC50) was calculated and the recommended safety level for L. vannamei cultivation is 60.05 and 127.61mg.L-1 of nitrate for salinities 5 and 10g.L-1, respectively.
RESUMO: Diferentes tecnologias foram desenvolvidas para melhorar o desempenho do Litopenaeus vannamei em baixa salinidade, principalmente em sistemas super intensivos como sistema de recirculação e BFT (Biofloc Technology System). No entanto, há um acúmulo de compostos nitrogenados tóxicos aos camarões, como o nitrato, que em altas concentrações e dependendo da salinidade da água pode ser letal. Os testes de toxicidade aguda permitem analisar a relação entre o composto e outras variáveis abióticas ou bióticas. O objetivo deste trabalho foi determinar a toxicidade aguda e o nível de segurança do nitrato (N-NO3 -) em juvenis de L. vannamei nas salinidades de 5 e 10g.L-1. Para a salinidade de 5g.L-1, um controle e cinco tratamentos foram testados, com concentrações de nitrato 100, 500, 1500, 2500 e 3500mg.L-1. Para salinidade de 10mg.L-1, foi adicionada uma concentração de nitrato de 4500mg.L-1. Os juvenis foram expostos às concentrações durante 24, 48, 72, 96 horas em sistema estático. A Concentração Letal Média (CL50) foi calculada e o nível de segurança recomendado para o cultivo de L. vannamei é de 60,05 e 127,61mg.L-1 de nitrato para salinidadesde 5 e 10g.L-1, respectivamente.
RESUMEN
El trabajo se realizó en la finca Mar Agrícola del municipio de Tumaco, con el objetivo de estudiar la distribución de las especies del género Buenoa en condiciones ambientales homogéneas respecto a la temperatura, humedad y altitud, en hábitats acuáticos de agua dulce y otros, con diferentes grados de conductividad y dedicados al criadero del camarón marino Litopenaeus vannamei (Boone, 1931). Los lagos estudiados fueron cuatro de agua dulce y cuatro con diferente conductividad, en los meses de junio a noviembre del 2010. Los resultados indican la distribución heterogénea de las especies del género Buenoa con mayor diversidad en ambientes dulceacuícolas (5 especies) y menor abundancia; mientras en ambientes salobres hay menor diversidad (4 especies) y mayor abundancia. Solo la especie Buenoa dactylis Padilla-Gil 2010 se encuentra en ambos ambientes acuícolas. Se discute posibles implicaciones ecológicas que puedan influir en este patrón de distribución.
The work was carried in the Mar Agrícola farm of the municipality Tumaco, with the objective of studying the distribution of the species of the genus Buenoa in homogeneous environmental conditions regarding temperature, humidity, altitude and aquatic habitats of the freshwater and the others with different grade of conductivity and dedicated to the marine shrimp farming Litopenaeus vannamei (Boone, 1931). The studied lakes were four of freshwater and four with different conductivity, in the months of June to November 2010. The results showed heterogeneous distribution of the species of the genus Buenoa with major diversity in freshwater (5 species) and lower abundance; while in saltwater had lower diversity (4 species) and major abundance. Only Buenoa dactylis Padilla-Gil 2010 was found in both aquatic environments. It is discussed possible ecological implications than can influence this distribution pattern are discussed.
RESUMEN
Body weight of Pacific white shrimp [Penaeus (Litopenaeus) vannamei] at 130 days of age was analyzed in three environments corresponding to different management systems: semi-intensive (10 shrimp/m²) in Pozos, Sinaloa (POZOS10), intensive (30 shrimp/ m²) in Pozos, Sinaloa (POZOS30), and super-intensive (85 shrimp/m²) in Bahia de Kino, Sonora (KINO85). Data were obtained from 18 087 sibs from 113 sires and 143 dams. The aim of the study was to evaluate the presence of genotype by environment interaction effects (IGA) and the effect of the (co) variance between full-sibs family common effects on the genetic parameter estimates. Estimates of h² with a model including independent full-sibs family common effects were between 0.26 and 0.39 across environments, while the estimates for a model with correlated full-sibs family common effects were estimated between 0.14 and 0.23. No differences were found for h² values between environments. The genetic correlations between environments were not lower from unity with any model; therefore, it is concluded that no evidence of genotype-environment interaction exists for body weight at 130 days in Pacific white shrimp, under the environments used in this study. The inclusion of the (co)variance between full-sibs family common effects of different environments affected the parameter estimates. These results also indicate that ranking of the breeding animals will be similar in all the studied production environments.
Se analizó información de peso corporal de camarón blanco del Pacífico [Penaeus (Litopenaeus) vannamei] a los 130 días, en tres sistemas de manejo: semiintensivo (10 camarones/m²); intensivo (30 camarones/m²), ambos en Pozos, Sinaloa, y super-intensivo (85 camarones/m²), en Bahía de Kino, Sonora. Los registros corresponden a 18 087 individuos, hijos de 113 sementales y 143 hembras, con la finalidad de evaluar la existencia de interacciones genotipo por ambiente (IGA) y el efecto de la covarianza de los efectos comunes de familia de hermanos en la estimación de parámetros genéticos. Las estimaciones de h² con un modelo que consideró los efectos comunes de familia de hermanos como independientes, fueron de 0.26 a 0.39 y de 0.14 a 0.23, para un modelo que consideró dichos efectos como correlacionados. No existió diferencia significativa entre los valores de h² de los ambientes, y las correlaciones genéticas entre ambientes no fueron menores a uno con ninguno de ambos modelos, se concluye que no hay evidencia de IGA en el peso corporal a los 130 días de P. vannamei en los ambientes estudiados en este trabajo. La inclusión de la covarianza entre efectos de familias de hermanos en el análisis afectó los valores de los parámetros. Se concluye que el ordenamiento de los reproductores será similar en los ambientes estudiados.