Temporal effects and changes in the parasitic community of Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae) in a floodplain

The construction of dams causes several impacts on aquatic environments, altering the flow of rivers, environmental variables, and all biota present, including parasites. Little is known about how the parasitic community can be influenced in the long term by environmental changes. In this study, it was expected that the impacts caused by environmental disturbances will be directly reflected by the composition of the parasite populations. We evaluated the change in the structure of the Prochilodus lineatus endoparasite community between two periods sampled 15 years apart in the upper Paraná River floodplain. There was a significant difference in the weight–length relationship of P. lineatus between these periods and a total of 15 species of parasites were found: 11 species in Period 1 and nine species in Period 2 and five species occurred in both periods. The species richness and diversity were higher in Period 1, and we observed that the correlation of descriptors (richness, diversity and evenness) increased with fish length in this period. In both periods, digeneans numerically dominated the parasitic community, and we verified changes in the composition of parasites between periods. Both the host and the parasites were possibly affected by the environmental impacts resulting from the construction of dams over time, and it is noteworthy that complex life cycle parasites such as Digenea and Acanthocephala require intermediate hosts to complete their life cycle, and the population responds to fluctuations in the face of modified environments.

Parámetros Productivos de dos Especies de Peces Autóctonos (Piaractus mesopotamicus y Prochilodus lineatus) en un Sistema Acuapónico con Lechuga (Lactuca sativa sp)

Se analizó el comportamiento productivo de dos especies de peces autóctonos bajo un sistema intensivo de producción acuapónica. El sistema contó con cuatro módulos, dos para Pacú: M2 y M3 y dos para Sábalo: M1 y M4. Cada módulo estaba constituido por un tanque de 1000 l para los peces, un tanque sobre elevado de 200 l, que recibía el agua del tanque de peces y un biofiltro de 15 l que drenaba en los sistemas hidropónicos, los cuales tenían una superficie de 4 m2 por módulo y un flujo de agua en el sistema de 2 l/minuto. Los parámetros de calidad de agua (oxígeno, pH, temperatura y conductividad eléctrica) se mantuvieron dentro de valores aceptables para la cría de los peces y para el crecimiento de la lechuga. En la serie nitrogenada (nitrito, nitrato, amonio, amoníaco) se observaron variaciones en los diferentes módulos, sin llegar a valores críticos. Respecto a los índices productivos de los peces, se obtuvo un mejor desempeño en Pacú, obteniéndose después de 37 días de cultivo una biomasa de 6.900 y 6.930 g para los módulos 2 y 3 de Pacú y 4.780 y 5.090g para los módulos 2 y 4 de Sábalo, respectivamente. Para la lechuga, la biomasa total fue de 7.482, 4.872, 8.584 y 10.672 g para los módulos 1, 2, 3 y 4, respectivamente. Los resultados indican que el Pacú es una especie de pez alternativa para la producción de acuaponía.

Morphological and cytochemical characterization of the peripheral blood cells of farmed streaked prochilod Prochilodus lineatus (Characiformes, Prochilodontidae)

ABSTRACT Morphological and cytochemical studies of peripheral blood cells of fish have improved the understanding of their functions and cell types. The present study performed the Morphological and cytochemical analysis of the peripheral blood of Prochilodus lineatus, Characiform native to South America, which has been gaining space in local aquaculture and as a species introduced in Asia. Our analysis provided information on the morphological and cytochemical characteristics of the leukocytes, for the formulation of hypothesis about their role in the immune system of the species. It was found that Prochilodus lineatus has morphological and cytochemical features in common with other fish species, mainly of the Characiformes order. However, we detected the presence of heterophils and PAS positive granulocytes simultaneously with neutrophils. We also found that heterophils and PAS positive granulocytes are very similar, both morphologically and cytochemically.

Improving the Efficiency of Lambari Production and Diet Assimilation Using Integrated Aquaculture with Benthic Species

A single farmed fish species assimilates about 20% of the nutrients in the supplied diet. This study evaluated if the culture of complementary ecological-function species can recover nutrients dispersed into water and transform them into high-valued biomass. A completely randomized experiment was designed with three treatments and four replications of each production system: monoculture of lambari (Astyanax lacustris); integrated aquaculture of lambari and Amazon river prawn (Macrobrachium amazonicum); and integrated aquaculture of lambari, Amazon river prawn, and curimbatá (Prochilodus lineatus). Fingerlings of lambari (0.8 ± 0.8 g) were stocked in twelve earthen-ponds (0.015 ha) at the density of 50 fish m−2. Eight ponds were stocked with juveniles of Amazon river prawn (1.1 ± 0.2 g) at the density of 25 prawn m−2. Four of these eight ponds were stocked with curimbatá fingerlings (0.2 ± 0.1 g) at a density of 13 fish m−2. Only lambari was fed twice a day with an extruded commercial diet. The experiment lasted 60 days when lambari attained commercial size. The inclusion of prawn increased the total species yield from 1.8 to 2.4 t ha−1 cycle−1 and reduced the feed conversion ratio (FCR) from 2.5 to 1.8. The inclusion of prawn and curimbatá increased the total yield to 3.2 t ha−1 cycle−1 and reduced the FCR to 1.4. Therefore, the integrated culture of lambari, prawn, and curimbatá improves the use of space, water, feed, and benthic species to recover the large quantity of nutrients accumulated in the bottom of lambari pond production, converting them into high-nutritional and monetary-valued biomass.

Improving the Efficiency of Lambari Production and Diet Assimilation Using Integrated Aquaculture With Benthic Species

A single farmed fish species assimilates about 20% of the nutrients in the supplied diet. This study evaluated if the culture of complementary ecological-function species can recover nutrients dispersed into the water and transform them into high-valued biomass. A completely randomized experiment was designed with three treatments and four replications of each production system: monoculture of lambari (Astyanax lacustris); integrated aquaculture of lambari and Amazon river prawn (Macrobrachium amazonicum); and integrated aquaculture of lambari, Amazon river prawn, and curimbatá (Prochilodus lineatus). Fingerlings of lambari (0.8 ± 0.8 g) were stocked in twelve earthen-ponds (0.015 ha) at the density of 50 fish m-2. Eight ponds, were stocked with juveniles of Amazon river prawn (1.1 ± 0.2 g) at the density of 25 prawn m−2. Four of these eight ponds were stocked with curimbatá fingerlings (0.2 ± 0.1 g) at a density of 13 fish m-². Only lambari was fed twice a day with an extruded commercial diet. The experiment lasted 60 days when lambari attained commercial size. The inclusion of prawn increased the total species yield from 1.8 to 2.4 t ha-1 cycle-1 and reduced the feed conversion ratio (FCR) from 2.5 to 1.8. The inclusion of prawn and curimbatá increased the total yield to 3.2 t ha-1 cycle-1 and reduced the FCR to 1.4. Therefore, the integrated culture of lambari, prawn, and curimbatá improves the use of space, water, feed, and benthic species can recover the large quantity of nutrients accumulated in the bottom of lambari pond production, converting them into high-nutritional and monetary-valued biomass.