Eduardo Luis Cupertino Ballester

Growth and survival of pink shrimp (Farfantepenaeus paulensis) postlarve in cages and pen enclosures

Um pacote tecnologico para o cultivo do camarao-rosa em estruturas alternativas de baixo custo, gaiolas e cercados, vem sendo aplicado em conjunto com pescadores artesanais do estuario da Lagoa dos Patos, no extremo sul do Brasil. Embora a tecnologia para o cultivo intensivo de pos-larvas (PL) em laboratorio ja esteja bem documentada, informacoes referentes a sobrevivencia e crescimento desses organismos na fase de bercario ainda sao escassas para cercados e gaiolas no ambiente natural. Em virtude destes fatos, o objetivo do trabalho foi comparar o crescimento e a sobrevivencia de pos-larvas de F. paulensis durante a fase de bercario em gaiolas e cercados no ambiente. Para o desenvolvimento do trabalho, foram utilizadas seis gaiolas (2,0 ´ 2,0 ´ 1,4 m) com malha de poliester revestida de PVC com abertura de malha de 1,5 mm. Em cada unidade foram estocadas 800 PL26. Para verificar a influencia do substrato, foram espalhados uniformemente 10 cm de sedimentos da propria enseada dentro de tres gaiolas, simulando um cercado. A taxa de sobrevivencia dos camaroes obtida nas gaiolas foi de 92,2% e nos cercados de 88,7%, nao sendo detectadas diferencas (P > 0,05). Porem, o peso medio final dos camaroes nos cercados (1,05 ± 0,05 g), foi superior (P < 0,05) ao peso dos camaroes nas gaiolas (0,88 ± 0,12 g). A especie pode ser cultivada na fase de bercario em gaiolas ou cercados sem prejuizo a sobrevivencia final. Entretanto, recomenda-se que a fase de bercario seja realizada preferencialmente em cercados.

Análise comparativa da criação dos camarões-rosa Farfantepenaeus brasiliensis e FarfantePenaeus paulensis criados em gaiolas em ambiente estuarino

The cage culture of Farfantepenaeus brasiliensis and Farfantepenaeus paulensis was analyzed in the Patos Lagoon estuary using juveniles produced in captivity. Mean initial weight of the juveniles was approximately 1.2g. The experiment was conducted in 6 cages (3 per treatment), with mesh size of 5mm and bottom area of 4m2, during 65 days. The individuals were randomly distributed into two treatments (F. brasiliensis e F. paulensis), keeping the stocking density of 20 shrimps m-2 in the experimental units (cages). Each 15 days shrimps were weighted to adjust the amount of feed and to evaluate growth. In the end of the experiment, all the shrimp were weighed and counted to determine the survival. Survival did not differ significantly between F. brasiliensis (94.17±9.04) and F. paulensis (98.50±0.71). Although the mean final weight was significantly higher for F. brasiliensis (7.98±0.94g), there were no significant differences in terms of total biomass production (127.81±17.93 e 126.65±1.74g m-2) and apparent feed conversion ratio (1.39±0.27 e 1.57±0.09) between F. brasiliensis and F. paulensis, respectively. The results indicate that F. brasiliensis show potential to be cultured in alternative systems and motivate the development of the technological package for culture of this species in the Patos Lagoon estuary.

Contribution of bioflocs to the culture of Litopenaeus vannamei post-larvae determined using stable isotopes

The aim of this study was to use preselected quality indicators for Litopenaeus vannamei post-larvae and the stable isotopes technique with δ13C and δ15N to determine the influence of bioflocs in shrimp feeding during the nursery phase, between PL1 and PL30. A control treatment (CT) with water renewal was compared to a biofloc treatment (BT) that received organic carbon fertilizations. Different types of commercial feed (Stresspak and Flake-INVE™, PL40-GUABI™), microalgae (Chaetoceros muelleri) and Artemia sp. nauplii were used as food sources. The physical and chemical parameters of water and ammonia were monitored daily, and nitrite, nitrate and alkalinity were measured weekly. Suspended solids and the microorganisms of bioflocs were characterized. At the end of the experiment, fifteen shrimps of each replicate were collected to evaluate nine larvae quality indicators. Isotopic values of 13C and 15N of food sources and shrimp tissues were collected on days 10, 20 and 30, and a Bayesian model of isotopic mixture measured the contributions of these sources to the shrimp biomass. Salinity, alkalinity and nitrite differed significantly between the treatments but were appropriate for post-larvae production. The larvae quality conditions in the CT treatment were ranked as “good,” whereas the BT conditions were considered “excellent” according to the analysis of larval quality parameters. The stable isotopes analysis showed that the PL40 GUABI™ feed was the most important food source throughout the experimental period in the CT. In the BT (10th and 20th days), the bioflocs and commercial feeds (Flake-INVE™, PL40-GUABI™) did not present significant variations in their contribution ratios; however, on the 30th day, the contribution of the PL40-GUABI™ feed was higher when compared to bioflocs. In general, the commercial feed played a more important role as a food source for Litopenaeusvannamei larvae during the nursery phase, although the consumption of bioflocs led to a better larvae quality.

Histological alterations in gills of Macrobrachium amazonicum juveniles exposed to ammonia and nitrite

Aquaculture has shown great growth in the last decades. Due to the restrictions on water use, production systems are becoming increasingly more intensive, raising concerns about the production water quality. Macrobrachium amazonicum is among the freshwater prawn species with favorable characteristics for production and possibility of intensification. Nitrogen compounds such as ammonia and nitrite affect the health of aquatic organisms since they quickly reach toxic concentrations. These compounds can also cause damage to the gill structure, leading to hypoxia in tissues, affecting acid-base balance, osmoregulation (salt absorption) and ammonia excretion, decreasing the immune capacity of the animal and, in extreme cases, cause death. The aim of this study was to assess histological changes in the gills of Macrobrachium amazonicum juveniles subjected to different concentrations of total ammonia and nitrite. The prawns were subjected to different concentrations of those compounds and their gills were removed and preserved for histological analysis. The gills were assessed for changes according to the Organ Index (Iorg) and, for each change, an importance factor (w) was attributed according to the degree of reversibility and applied according to the degree of extension or frequency of the damage. The damage to the gills in the treatments with 100% mortality, both for ammonia and nitrite, corresponded to the high occurrence of progressive, regressive, circulatory, and inflammation damages. The other treatments (which caused less mortality) had mainly inflammation and regressive damages, whose occurrence increased according to the increase in ammonia and nitrite concentration. The histological analysis confirmed that the higher the total ammonia and nitrite concentrations, the larger the damages caused to the gill structure and that lower nitrite concentrations caused similar damages to those caused by higher total ammonia concentrations, which reflects the lower capacity M. amazonicum has to tolerate nitrite.

Uso de probióticos na produção de pós-larvas de camarão-rosa

The objective of this work was to evaluate the use of probiotics in the production of postlarvae of pink shrimp (Farfantepenaeus brasiliensis). A completely randomized experimental design was used, with two treatments - use of probiotics (Bacillus spp.), and a control using antibiotic (erythromycin) -, and four replicates. Postlarvae in the PL1 stage were stocked in each experimental unit (3.0 L) and cultured until stage PL10. Water quality variables and the development of the bacteria of the genus Vibrio, in the culture water, were monitored throughout the experiment. At the end of the experimental period, postlarvae were evaluated qualitatively and for survival, weight, and length. Regarding water quality variables, only nitrite was significantly higher in the antibiotic treatment. For the variables weight and length, there were no significant differences between treatments. No significant differences between treatments were observed in postlarvae quality and in the concentration of Vibrio spp. in the water. The use of antibiotics may be replaced by probiotics during production of F. brasiliensis postlarvae.

Replacement of protein source in practical diets for Amazon River Prawn

The aim of this study was to evaluate the best level of substitution of fish meal (FM) by soybean meal (SBM), as protein source in practical diets for juveniles of Macrobrachium amazonicum. Juveniles, with initial mean weight of 0.16 ± 0.66 g, were stocked at a density equivalent to 150 juveniles m-2 in a recirculating aquaculture system. Treatments consisted of the proportions of fish meal and soybean meal (FM:SBM) in diets, namely: 0: 100, 20:80, 40:60, 70:30, 100:0 with five replicates per treatment. At the end of the 45 days trial, prawns were counted, measured, weighed, and the bromatological analysis of the whole body was performed. Survival remained above 94% in all treatments (p>0.05). A corporal bromatological analysis showed significant among treatments only for crude protein (p <0.05). The results of the production performance showed that the inclusion of up to 30% of SBM in replacement for FM (70:30) did not interfere, significantly, in the performance of the prawns (p>0.05), making possible the use of soybean meal in diets for juveniles of Amazonian river prawn.