Dariano Krummenauer

NURSERY OF LITOPENAEUS VANNAMEI REARED IN A BIOFLOC SYSTEM: THE EFFECT OF STOCKING DENSITIES AND COMPENSATORY GROWTH

ABSTRACT The purpose of this study was to evaluate the effect of stocking density and the occurrence of compensatory growth in the white shrimp Litopenaeus vannamei in the nursery phase reared in a biofloc culture system. Two experiments were performed in a recirculating water system with 12 experimental tanks (microcosm), each with a bottom area of 0.5 m2. The tanks were supplied by a matrix 70-m2 biofloc technology water tank (macrocosm), where a shrimp biofloc technology systems culture was maintained concurrently. The water was returned to the system by gravity, providing a daily renewal rate of approximately 4,800%. During the first experiment, L. vannamei postlarvae with an initial weight of 0.003 g were cultured for 30 days at densities of 1,500, 3,000, 4,500, and 6,000 shrimp/m2. The cultures reached significantly different final weights (P < 0.05) of 0.45 g, 0.33 g, 0.30 g, and 0.23 g, respectively. Mean survival rates were greater than 87.6% in all treatments. To evaluate the occurrence of compensatory growth in L. vannamei after a period of enclosure stress, the second experiment was organized in 2 phases. During the first, shrimp postlarvae were reared at densities of 1,500, 3,000, 4,500, and 6,000 shrimp/m2 for 35 days. The shrimp were then restocked at a density of 300 shrimp/m2 and were maintained until compensatory growth was observed. In 20 days, the shrimp showed full compensatory growth. The mean final weight and survival rate did not differ significantly (P > 0.05) between the treatments. The results confirm that the strategy of enclosure rearing can be applied to the culture of L. vannamei.

Viabilidade do cultivo do camarão-rosa Farfantepenaeus paulensis (Crustácea, Decapoda) em gaiolas sob diferentes densidades durante o outono no sul do Brasil

Neste trabalho, foi estudada a possibilidade de cultivar o camarao-rosa Farfantepenaeus paulensis em gaiolas com diferentes densidades de estocagem durante o outono (abril a junho) no estuario da Lagoa dos Patos, RS. Juvenis com peso medio de 4,95g (± 1,69 dp foram estocados em gaiolas nas densidades de 20, 40, 80, 100 e 120 ind/m2. Os camaroes foram alimentados diariamente ad libitum com pedacos de Corvina (Micropogonias furnieri). As sobrevivencias e os pesos foram observados nos tempos 20, 40 e 60 dias de experimento. Durante o periodo de cultivo a temperatura da agua decresceu de 24 para 11°C (media = 17,1°C) e a salinidade oscilou entre 3 e 26 (media = 17,5). As taxas de sobrevivencia nas densidades de 20, 40, 80, 100 e 120 ind/m2 foram 65%, 68%, 46%, 52% e 43,3% respectivamente, sendo significativamente maiores nas densidades de 20 e 40 ind/m2. Apos 60 dias, os camaroes estocados em 20 e 40 ind/m2 atingiram peso superior a 8,0g, sendo significativamente maiores (P<0,05) que nos demais tratamentos. A maior biomassa (356g) foi obtida na densidade de 120 ind/m2. Foram produzidos de 250 a 350g de camaroes com peso medio de 6,5 a 8,0g por m2, mesmo em altas densidades de estocagem (40 a 120 ind/m2). As taxas de sobrevivencia dos camaroes mantidos em 20 e 40 ind/m2 podem ser consideradas satisfatorias, contudo, apos a temperatura ficar abaixo de 18°C, as taxas de crescimento foram reduzidas. Os resultados confirmam o efeito negativo da densidade de estocagem sobre o crescimento dos camaroes, sendo recomendada a estocagem de 40 a 120 juvenis/m2. Foi, contudo, comprovada a possibilidade de cultivar F. paulensis durante o outono no sul do Brasil.

Nursery of Pink Shrimp Farfantepenaeus paulensis in Biofloc Technology Culture System: Survival and Growth at Different Stocking Densities

ABSTRACT Farfantepenaeus paulensis postlarvae were reared at different stocking densities during the nursery phase in a biofloc technology (BFT) culture system without water exchange. An experimental system comprising a 70-m3 macrocosm tank containing shrimp cultured in the BFT system at 300 shrimp/m2, with a productivity of 2.7 kg/m2 was used, which supplied twelve 0.5-m2 tanks at densities of 500, 1,000, 1,500, and 2,000 shrimp/m2 through pumping. The experiment lasted for 30 days. The water was recirculated 48 times a day from the macrocosm to the microcosm tanks. The growth rate, final weight, survival, and productivity of the shrimp were analyzed. There were no significant differences in the water quality parameters among treatments because the water input and output from the macrocosm tank to the experimental units was constant. There were also no significant differences (P > 0.05) in survival. However, the final weight and productivity were significantly different (P < 0.05) among treatments. The treatments with the lowest stocking densities were associated with the highest weights, whereas the treatments with the highest stocking densities presented the highest productivities. The study demonstrates that the use of a BFT culture system may enable the culture of this species at high stocking densities in nurseries. The results also demonstrate the possibility of using a high stocking density for commercial culture and restocking programs.

Influence of artificial insemination on the reproductive performance of Farfantepenaeus paulensis in conventional and unisex maturation systems

The application of artificial insemination techniques as a way to overcome the lack of mating of the closed thelycum Farfantepenaeus paulensis under large scale conditions is reported. The performance of artificially inseminated females (49.4 ± 11.6 g) maintained in conventional versus unisex maturation systems was compared. Groups of unilaterally eyestalk-ablated females were artificially inseminated with one compound spermatophore soon after molting. The percentage of fertilized spawns increased from 26% before the use of artificial insemination to 57% afterwards. The reproductive performance of inseminated females held in conventional or unisex maturation systems showed no significant differences. Artificial insemination was considered a practical approach to overcome the lack of mating of F paulensis under large-scale conditions with acceptable reproductive performance. The results also indicate the possibility of holding females separately from males, which could mean significant improvements in maturation systems through the increase in the stocking density of spawning females.

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.

The Effect of Probiotics in a Litopenaeus vannamei Biofloc Culture System Infected with Vibrio parahaemolyticus

We analyzed the effect of commercial bacterial probiotics on a Litopenaeus vannamei biofloc culture system infected with Vibrio parahaemolyticus. Three replicates of two experimental treatments were conducted: a control system (without probiotic) and a system with the application of a multistrain probiotic containing Bacillus spp., Enterococcus spp., Thiobacillus spp., and Paracoccus spp. applied to the water and another multistrain probiotic containing Bacillus spp., Enterococcus spp., and Lactobacillus spp. added to the feed. Growth and survival rate were significantly higher in the probiotic treatment group (P < 0.05), and the shrimp in the probiotic group also had a lower (P < 0.05) FCR compared to the shrimp in the control group (1.4 vs. 2.7).

A Comparison of the Reproductive Performance of the Wild Pink Shrimp Species Farfantepenaeus paulensis and Farfantepenaeus brasiliensis in Captivity

ABSTRACT The aim of this study was to compare the reproductive performance of the wild shrimp species Farfantepenaeus paulensis and Farfantepenaeus brasiliensis in captivity. The broodstocks were collected in offshore waters in Santa Catarina and transferred to the Marine Station of Aquaculture of the Federal University of Rio Grande. Broodstocks with a similar body weight between the two species were selected to measure reproductive performance. Females with mature ovaries were identified each day to obtain measures of reproductive performance. After spawning, fertilization rates were determined by microscopic examination. In addition, three samples of 100 eggs were collected to determine hatching rates, and three samples of 100 nauplii were collected to evaluate the rate of metamorphosis to protozoa. For males, spermatophores were manually extruded, weighed, and homogenized in 2 mL calcium-free saline solution, and 0.1 mL trypan blue was added. Sperm counts, abnormal cells (malformations of the main body or absence of the spike), and dead cells (blue coloration) were estimated with cell counts, using a hemacytometer under a light microscope. Spermatophore melanization was checked. The larval production of the two species was similar, but F. brasiliensis spawned in less time after unilateral eyestalk ablation. The spermatophore weight and sperm count were higher in the F. brasiliensis males, and none of the shrimp showed melanization.

The use of different aerators on Litopenaeus vannamei biofloc culture system: effects on water quality, shrimp growth and biofloc composition

This study evaluated the effects of different aeration types on water quality, shrimp growth and biofloc composition in a Litopenaeus vannamei culture. The study was conducted with three treatments: (1) PR—propeller aspirator pump aerator; (2) VP—vertical pump aerator; and (3) BL—diffused air blower. The study was performed in a greenhouse with nine 35,000-L rectangular tanks. Water quality parameters (temperature, salinity, dissolved oxygen, pH, ammonia, nitrite, nitrate, settleable and suspended solids) were measured along the 33 experimental days. Moreover, samples were collected to quantify the microorganisms present in the tanks. At the end of the study, samples of the biofloc of each tank were collected to proximal analysis. Throughout the experiment, the temperature, pH, salinity and alkalinity were maintained within the recommended levels for L. vannamei. The propeller treatment showed a concentration of total ammonia above the recommended levels and lower densities of ciliates and flagellates, most likely because of inadequate biofloc formation in this treatment. The final weight was higher in the blower and propeller treatments. However, survival was lower in the propeller treatment compared to the other treatments. The results of this study suggest that diffused air systems (air blower) improve the formation of biofloc and growth performance of L. vannamei.

Long term storage and the compensatory growth of white shrimp Litopenaeus vannamei in aquaculture ponds

Effects of shrimp confinement in a situation of high density stocking in a long term nursery on their growth performance in grow out ponds. Were analized two nurseries with a density of 2000 shrimp m -2 were stocked at two different times. The first nursery (LTN) lasted 144 days, and the SGR of the animals was 3.0% day -1 . The second nursery (STN) lasted 18 days and the specific growth rate (SGR) was 19.9% day -1 . On the same day, shrimps were transferred to six lined ponds at a density of 20 shrimp m - ² where they remained for 101 days. In the first biometry, the SGR in the LTN treatment, increased to 6.7% day -1 and in the STN it decreased to 5.0% day -1 . At the end, shrimps of the LTN and STN treatments reached weights of 8.46 and 6.72 g and had productivities of 1287 and 1015 kg ha -1 , respectively. Shrimps reared in nurseries for long periods showed growth and survival rates similar to those obtained using conventional management practices in grow out structures.

Densidade de estocagem na engorda de camarão-branco cultivado em sistema de biofloco

The objective of this work was to determine the optimal stocking density for Pacific white shrimp farming, in biofloc culture system (BFT) without water exchange. Two completely randomized experiments were carried out, with three replicates for each treatment. In the first experiment, juveniles with 1.23±0.09 g initial mean weight were reared at the stocking densities of 833, 1,250, 1,667, 2,083, and 2,500 shrimp per m3. In the second experiment, the initial mean weight was 6.32 ± 0,7 g, and the densities were 566, 833, 1,111, 1,388, and 1,667 shrimps per m3. The best productivity results, with the means 9.92 and 10.77 kg m-3, were obtained at 1,667 and 1,111 shrimp per m3, respectively, in the first and second experiments. Increasing stocking density affects growth and survival of white shrimp farmed in biofloc system.