Silvio Peixoto

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.

Métodos de extrusão manual e elétrica dos espermatóforos de reprodutores selvagens do camarão-rosa Farfantepenaeus paulensis (Decapoda: Penaeidae)

The present study compared manual and electrical methods to extrude the spermatophore of the pink shrimp Farfantepenaeus paulensis aiming to analyze their influence on the number of spermatic cells and spermatophore regeneration. The males were extruded in the beginning (day zero) and in the end (43rd day) of the experiment to evaluate the efficiency of these methods in the regeneration process. For the extrusion, a gentle pressure was applied manually in the fifth pair of pereiopods or electrically by a 9 volt pulse in the same area. Both methods were efficient in removing the spermatophore and no significant differences were found (P>0.05) in the number of sperm cells. Nevertheless, significant decreases (P<0.05) in the body weight, spermatophore weight and spermatosomatic index (ESI) at the end of the experimental period were observed by using the electrical stimulation. The mean values (±SD) of the number of sperm cells were 1.46 (±0.84) and 3.25 (±2.12) millions for the electrical and manual treatments, respectively. Results indicate that both methods may be applied to collect initial samples of spermatophores as well as for sperm quality testing. However, when previously spermatophore-extruded males are to be used, the manual method is indicated as the number of spermatic cells, spermatophore weight, body weight, and ESI are maintained after regeneration.

Scanning electron microscopic investigation of the spermatophore and spermatozoa of the shrimp Farfantepenaeus subtilis (Decapoda: Penaeidae)

Scanning electron microscopy was used to describe the structure of the spermatozoon and spermatophore of Farfantepenaeus subtilis. The spermatophore showed characteristics similar to those of members of the subgenus Farfantepenaeus. This included an extensive glandular epithelium and a lack of a wing. The sperm mass, which was distributed at the periphery of the spermatophore, was surrounded by a large amount of acellular material. The spermatozoon has a spherical main body and a well-defined acrosomal region with a single spike, which was bent in some cells. The immotile sperm cells have an average length of 7.1 ± 0.6 μm. Information on sperm location within the spermatophore will assist in the efficient extraction of the sperm mass during dissection.

POPULATION DYNAMICS OF THE PINK SHRIMP FARFANTEPENAEUS SUBTILIS (PÉREZ-FARFANTE, 1967) IN NORTHEASTERN BRAZIL

This study provides information on the population structure, growth, mortality, maximum recruitment yield, and longevity for pink shrimp Farfantepenaeus subtilis (Perez-Farfante, 1967) on the coast of Pernambuco state, northeastern Brazil. A total of 1246 specimens (545 males and 701 females) were monthly collected from August 2011 to July 2012. Mean total length of females was higher (11.42 ± 1.61 cm) than males (10.5 ± 1.62 cm) and dominated in the largest length classes. Estimation of von Bertalanffy growth parameters for total length resulted in L∞ of 19.74 cm and k of 1.06 year −1 for males, while females’ L∞ was 21.64 cm and k was 1.10 year −1 . Mortality of females was higher than males resulting higher value in the exploitation rates. The exploitation rate for maximum recruitment yield was similar between males and females with a value of 0.67, which was above the exploitation rates (0.50-0.64).

Use of Fluorescent Microscopy for Sperm Quality of Penaeids

The present study is the first attempt to evaluate the use of fluorescent microscopy as a tool for determining the sperm qualitity in penaeid shrimp species. The probes propidium iodide and 6-carboxyfluorescein diacetate (CFDA) were used in combination to assess sperm quality of Litopenaeus vannamei captive broodstock and wild stocks of Farfantepenaeus subtilis and Litopenaeus schmitti. L. vannamei showed a significant higher amount of live cells (80.87%) after 93 days in captivity, when compared to animals entering (day 0) the maturation system (61.03%). The percentages of live sperm cells for wild-caught F. subtilis and L. schmitti were above 50% over the 12-month sample period in northeastern Brazil. These results demonstrate that the fluorescent microscopy can be used as a tool to determine the sperm quality in penaeid, allowing the evaluation of male performance in aquaculture systems, as well as to determine their reproductive cycle in fisheries research.

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.

Atypical Chytridiomyces Fungal Infection in Cultured Macrobrachium rosenbergii in India

In the present study we report ectoparasite infection in pond-cultured Macrobrachium rosenbergii from southeast coast of Tamilnadu, India. The symptoms included a thick layer of whitish hair covering the entire body, sluggish movement, decrease of food intake and abnormal migration to the pond corners. Laboratorial analysis identified fungi from the genus Chytridiomyces, which have been associated to mortalities during freshwater prawn culture in India.

Sperm vitrification of Litopenaeus vannamei: effect of cryoprotectant solutions on sperm viability and spawning quality after artificial insemination

Vitrification is a fast freezing method with promising results for penaeids sperm cryopreservation. This study evaluated the efficiency of three cryoprotectant solutions for sperm vitrification and artificial insemination with cryopreserved spermatophores of Litopenaeus vannamei. The cryoprotectant solutions tested were 30% methanol, 2% soy lecithin, and 30% methanol + 2% soy lecithin. Fully mature females were artificially inseminated with vitrified and fresh spermatophores as a control group. The vitrification method was efficient in maintaining high rates of sperm survival and membrane integrity. Although the egg fertilization was successfully attained by artificial insemination with cryopreserved spermatophores, low hatching rates suggested that possible DNA fragmentation of sperm cells should be further investigated. This is the first report of artificial insemination using vitrified sperm in penaeids.

Reproductive cycle of seabob shrimp Xiphopenaeus kroyeri (Crustacea, Penaeidea) from the northeast coast of Brazil

Abstract The reproductive cycle of Xiphopenaeus kroyeri north-eastern Brazil was described to contribute to the sustainable management of this stock in the region. Specimens were collected monthly from August 2011 to July 2012 using a local vessel of the artisanal fleet. A total of 1201 individuals were analyzed (673 females and 528 males) with a mean carapace length (CL) of 1.88 ± 0.16 cm and total length (TL) of 9.00 ± 1.22 cm. The lowest CL and TL of mature females were 1.33 and 6.5 cm, respectively, and all females above 2.44 cm (CL) and 11.5 cm (TL) were mature. Ovarian maturation was classified into four stages: I (immature), II (maturing), III (mature) and IV (spawned). Individuals of all maturational stages were present throughout the year. Considering the macro and microscopic analysis, it was suggested that this species in north-eastern Brazil has a continuous reproductive cycle, with two seasonal peaks, November/December and February (austral spring and summer). A positive correlation between the percentage of mature females and temperature was observed, and a higher percentage was reported in the warmer months of the year. This suggests that the reproductive peaks can be triggered by water temperature variation throughout the year.

Technical efficiency analysis of marine shrimp farming (Litopenaeus vannamei) in biofloc and conventional systems: A case study in northeastern Brazil

Shrimp farming has a great ecological, economic, and social importance in northeastern Brazil. Although the conventional farming system is widely used, biofloc technology (BFT) system has been developed to reduce environmental impacts and optimizing the production. Thus,the present study evaluated the technical efficiency of production cycles of Litopenaeus vannamei in conventional and BFT systems.We analyzed 48 production cycles in the conventional system in 2013 and 2014 and 9 cycles in the BFT system in 2014 through data envelopment analysis (DEA). The inputs corresponded to the population density (post-larvae m-2), amount of feed (kg ha-1 cycle-1), labor (man ha-1) and power supply (HP ha-1), whereas the yield (kg ha-1 cycle-1) was considered the output. The results indicated four production cycles (7.0%) technically efficient, three in the conventional system and one in the BFT. By comparing the productive systems, there was significant difference in their mean scores of technical efficiency. There was a greater influence of the management inefficiency on the conventional system, while the production scale reduced the average scores of technical efficiency in the BFT system. These results may help to improve the development of sustainable L. vannamei farming in both systems by reducing waste and increasing profits.