Abstract Diet supplementation with essential oil from sweet basil Ocimum basilicum (EOOB) can increase fish growth. So, this study aimed to evaluate the effect of EOOB in the diet on growth performance and plasmatic variables of pirarucu juveniles (Arapaima gigas) submitted to stressful condition (stocking density of 7.56 kg m-3per tank and limited space). Four diets (in triplicates) were evaluated with increasing levels of EOOB (0.0 control; 0.5; 1.0; and 2.0 mL kg diet-1) over 48 days. Linalool was the major constituent of EOOB (54.19%). The addition of 2.0 mL EOOB kg diet-1 improved final weight, weight gain, specific growth rate, condition factor and feed conversion ratio; it also decreased plasma urea levels and increased plasma albumin and total proteins levels. Plasma glucose, cortisol, and acid uric levels were not influenced by the addition of EOOB to the fish diet. In conclusion, the addition of 2.0 mL EOOBkg diet-1 is recommended for pirarucu juveniles, due to improved growth performance, and this supplementation did not compromise the homeostasis of fish rearing in a high stocking density.

Abstract Although fish may live in different aquatic environments, variations in the water quality parameters, mainly pH, may have a substantial impact in their development and welfare. The objective of this study was to test the effect of different pH levels on the growth performance and biochemical variables in Amazon catfish juveniles (Pseudoplatystoma reticulatum x Leiarius marmoratus). Fish were subjected to four different water pH levels (4.56, 6.0, 7.24, and 8.90) for 40 days. The total ammonia and alkalinity were higher and lower, respectively, in the treatments with water pHs 4.56 and 6.00 than at the other water pH levels. The un-ionized ammonia was higher at water pH 8.90 than at the other water pH levels. Amazon catfish exposed to water pH 4.56 presented specific growth rate and weight gain significantly higher than other water pH values. In general, fish under exposure to water pH 8.90 presented lower growth performance than other water pH values. Biochemical changes were recorded at all water pH. In conclusion, water pH 4.56 is recommended for an Amazon catfish production system, since fish presented higher growth and water quality variables were kept within adequate limits for aquaculture.

Las metalotioninas (Mts) se han utilizado como biomarcadores debido a que metales tóxicos como Hg, Cd, Cu pueden inducir su síntesis; sin embargo, los factores ambientales y la presencia de otros xenobioticos pueden determinar la magnitud de la respuesta en futuras exposiciones a iones metálicos. En el presente trabajo se evaluó la concentración de Mts en el tejido blando de ejemplares juveniles de Perna viridis preexpuestos a Cu y luego a Cd (Cu/Cd) durante 21 días, para lo cual se establecieron tres grupos experimentales: expuestos a Cd, preexpuestos a Cu y expuestos a Cd y el grupo control (sin metal). La acumulación de Cd en los tejidos fue significativamente mayor en los organismos preexpuestos a Cu, con un valor promedio de 6,64 ± 1,90 μg/g, mientras que en los expuestos a Cd, fue de 4,74 ± 2,33 μg/g. Las concentraciones de Mts también fueron mayores en el grupo Cu/Cd con un valor de 1,36 ± 0,52 μg/g con relación a los expuestos a Cd con un valor de 0,79 ± 0,47 μg/g durante los 21 días de exposición. La relación entre los niveles de Mts y la bioacumulación de Cd resultó ser lineal y significativa en el grupo expuesto a Cd, pero no en el expuesto a Cu/Cd. Estos resultados sugieren que el Cu posiblemente actuó como un inductor de Mts en el organismo, lo que propició un aumento de la acumulación de Cd en P. viridis y un incremento en la concentración de la Mts, lo que determina que la tolerancia y la bioacumulación de Cd en P. viridis está determinado por exposiciones previas y por ende su respuesta en los niveles de MTs también depende de ésto.

The metallothioneins (Mts) have been used as biomarkers because toxic metals such as Hg, Cd, Cu can induce their synthesis; however, environmental factors and the presence of other xenobiotics can determine the magnitude of the response in future exposures to metal ions. Metallothionein concentration was determinate in the soft tissue of Perna viridis juveniles pre-exposed to Cu and exposed to Cd (Cu/Cd) for 21 days. For this, three experimental groups were established: exposed to Cd, pre-exposed to Cu and exposed to Cd and the control group (no metal). Cadmium accumulation in tissues of P. viridis was significantly higher in pre-exposed organisms to Cu, with an average value of 6.6 ± 1.9 mg/g, while in those exposed to Cd, was 4.7 ± 2.4 mg/g. Mts concentrations were also higher in the Cu/Cd experimental group, with a value of 1.36 ± 0.52 mg/g in relation to those exposed to Cd which had a value of 0.79 ± 0.47 mg/g. The relationship between Mts and bioaccumulation of Cd was significant in the group exposed to Cd, but not in the exposed Cu/Cd. These results suggest that Cu possibly acted as an inducer of Mts in the body, which led to increased accumulation of Cd in P. viridis and increase in Mts concentration. Tolerance and bioaccumulation of Cd in P. viridis was determined by previous exposure of the organism and hence its response on levels of MTs also depends on it.

Mercury levels were determined in green mussels, Perna viridis, from two localities of Sucre State (Venezuela): Chacopata and Río Caribe. Specimens were captured in the intertidal zone from February to December 2003. They presented anteroposterior lengths ranging from 18 to 113 mm and were classified, according to their sexual maturity, as juveniles or adults. Mercury was determined by flame atomic absorption spectrophotometry and the method of analysis was validated using certified standards. Seasonal variations were significant at both sites. Highest mercury concentrations in the Chacopata specimens were recorded during February (mean value of 0.432 ± 0.472 µg g-1 d.w.) and in the Río Caribe specimens during April (mean value of 1.129 ± 0.763 µg g-1 d.w.). No relation between mercury levels and sexual maturity was found at Chacopata, but a relation was observed at Río Caribe. Immature organisms showed the highest concentrations (0.471 ± 0.679 and 0.688 ± 0.894 µg g-1 d.w. for males and females, respectively).

Se determinaron los niveles de mercurio en el mejillón verde, Perna viridis, provenientes de dos zonas del Estado Sucre (Venezuela), Chacopata y Río Caribe. Los especimenes de P. viridis fueron capturados en la zona intermareal de febrero a diciembre de 2003. Los ejemplares presentaron tallas comprendidas entre 18 y 113 mm de longitud anteroposterior y fueron caracterizados de acuerdo con su madurez sexual en juveniles y adultos. La determinación del mercurio se realizó por espectrofotometría de absorción atómica y los valores fueron validados con estándares certificados. En ambas localidades se encontraron variaciones estacionales significativas; en Chacopata la mayor concentración de mercurio se encontró durante febrero, con un promedio de 0.432 ± 0.472 µg g-1 p.s., mientras que en Río Caribe ésta fue de 1.129 ± 0.763 µg g-1 p.s. durante abril. No se evidenció relación entre los niveles de mercurio y la madurez sexual en la localidad de Chacopata, pero sí en Rio Caribe donde los organismos inmaduros presentaron las mayores concentraciones (0.471 ± 0.679 y 0.688 ± 0.894 µg g-1 p.s. para machos y hembras, respectivamente).

The NA49 experiment at CERN SPS has acquired a huge data set of Pb+Pb events over a broad range of energy and centrality during the last several years. This high statistics data set, coupled with a state-of-the-art analysis technique, allows for the first model-independent extraction and energy scan of 3D emission sources for pion pairs at SPS energies. These 3D two-pion emission sources provide new insights into the nature of a long-range source previously reported by PHENIX at RHIC. The new results indicate that the two-pion source function is essentially Gaussian from 20 AGeV to 80 AGeV but it displays significant non-Gaussian tails at 158 AGeV.

The NA49 experiment at CERN SPS has acquired a huge data set of Pb+Pb events over a broad range of energy and centrality during the last several years. This high statistics data set, coupled with a state-of-the-art analysis technique, allows for the first model-independent extraction and energy scan of 3D emission sources for pion pairs at SPS energies. These 3D pion emission sources provide new insights into the nature of a long-range source previously reported by PHENIX at RHIC. Preliminary results indicate that the pion source function is essentially Gaussian from 20 AGeV to 80 AGeV but it displays significant non-Gaussian tails at 158 AGeV.

The static biossays were performed to determine lethal concentration (LC50) values of four heavy metals (Cd++, Cr+++. Cu++. and Zn++) of spotted brown shrimp (Penaeus brasiliensis) The test animals were collected from the Laguna of Restinga, Nueva Esparto, and were acclimated in the laboratory condition for 11-21 days. Temperature and salinity were 22 ºC and 36 ppt, respectively. The LC50 values (mg/l) determined by probability-logarithm transformation were as follows-cadmium: 38 (24 -h), 21 (48 -h), and 12 (60 -h);chromium:40 (48 -h), 23 (60 -h), 13 (86 -h), and 10 (96 -h); copper: 24 (48 -h), 19 (60 -h), 16 (72 -h), 14 (86 -h), and 10 (144 -h); and zinc: 69 (24 -h), 25 (36 -h), 15 (48 -h) and 8 (60 -h). The LC50 values of 48 -h and 60 -h indicate that the most toxic heavy metals to P. brasiliensis in order are zinc, cadmium, copper, and chromium.