Inferring population connectivity across the range of distribution of the stiletto shrimp Artemesia longinaris Spence Bate, 1888 (Decapoda, Penaeidae) from DNA barcoding: implications for fishery management

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Population structure, sex ratio and growth of the seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae) from coastal waters of southern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Annual, seasonal and spatial abundance of the seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae) off the Southeastern coast of Brazil

We investigated the influence of environmental factors in spatial and temporal distribution of the seabob shrimp Xiphopenaeus kroyeri in Santos Bay and São Vicente Estuary, state of São Paulo, Brazil. Monthly samples were obtained, from May 2008 through April 2010, from four locations in the estuary and four in the bay. No individual was collected in the estuary and this was attributed to the low salinity means recorded in this environment. We collected 109,153 individuals in the bay and there was no difference in abundance between the two years comprised by the study period. The similarity in spatial distribution can be related to sediment grain size that in all sampling locations showed great amount of very fine sand. The largest amount of reproductive females was obtained in early 2010, when temperature was high, and this could have increased the juvenile recruitment in April 2010. According to our results, the distribution of X. kroyeri in the study area is influenced by temperature, which is related to reproduction, and salinity, limiting the entrance of individuals in the estuarine region.

Diel Variation in Abundance and Size of the South American Red Shrimp Pleoticus Muelleri (Spence Bate, 1888) (Decapoda, Solenoceridae) in the Ubatuba Region, Southeastern Brazil

Diel variation in the abundance and size of Pleoticus muelleri in the Ubatuba region was investigated during 2000. During each season of the year, sampling was conducted during the day and at night at 8 depths, from 5 to 40 m. The estimated number of shrimp was 955 individuals, 272 collected during the day and 683 at night. There was a difference in the abundance of P. muelleri between day and night (χ², p=2.33E-40). The abundance during the day and at night differed by season with the exception of the spring (χ², p=0.06). The abundance during both periods also differed by depth, except at 15 and 30 m, where it was not significant (χ², p=0.84 and 0.06, respectively). The shrimp caught at night were generally smaller than those caught during the day (Kolmogorov-Smirnov, p<0.01). Pleoticus muelleri juveniles were found primarily at night. This tendency could have influenced the lower mean size for this period. The sediment type and the bottom temperature appear to influence the behavior of this species and consequently the catch rate during the periods analyzed.

Reproduction and recruitment of the seabob shrimp: a threatened exploitation species in southeastern of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ecological distribution of the shrimp Pleoticus muelleri (Bate, 1888) and Artemesia longinaris Bate, 1888 (Decapoda, Penaeoidea) in the southeastern Brazilian littoral

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of salinity on the metabolism and osmoregulation of selected ontogenetic stages of an Amazon population of Macrobrachium amazonicum shrimp (Decapoda, Palaemonidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diel variation in abundance and size of the seabob shrimp Xiphopenaeus kroyeri in the Ubatuba region, Southeastern Brazil

The objective of the present study was to analyze diel variation in the abundance and size of the seabob shrimp Xiphopenaeus kroyeri in the Ubatuba region, state of São Paulo, during the year 2000. In each season of the year, collections were made in the day and at night on 9 transects at depths ranging from 2 to 40 m. The estimated shrimp amount was of 28,878 individuals. Although the catch rate was higher during the day (15,853 shrimp), this did not differ significantly from the catch at night (13,025). The catch rate was higher in daytime on most transects, but was higher at night at locations where fine and very fine sand predominated. The majority of juveniles were caught during the day. The mean size (CL) was 14.43 ± 4.02 mm for day and 14.82 ± 4.28 mm for night samples, and the difference was significant (Student’s t-test, df = 2, 429, t = 2.27, p = 0.02). The largest individuals were caught during the night. None of the three models that have been proposed in the literature to account for differences in the diurnal catch pattern of penaeid species can be applied to X. kroyeri. Our results provide evidence that sediment type not only influenced the catch rate in the analyzed periods, but also determined which models might fit the behavior of this species.

Population ecology of the planktonic shrimp lucifer faxoni borradaile, 1915 (crustacea, sergestoidea, luciferidae) of the southeastern coast of brazil

Luciferid shrimps have short life spans and a rapid turnover of generations, engage in sequential spawning, and protect their eggs during incubation. This study investigates the ecology of Lucifer faxoni Borradaile, 1915 in the littoral zone, Ubatuba region, São Paulo. Sampling was conducted monthly from July 2005 to December 2006 using a Renfro net trawled over a distance of 50 m for a total sampling effort of 50 m² at each station. Nine stations were sampled, ranging from 1 to 15 m deep. Three stations each were grouped into zones 1, 2 and 3 (Z1, Z2 and Z3). Monthly values of salinity, temperature and rainfall were recorded at each station. The pre-buccal somite length (SL) of each specimen was measured. The results showed that in shallower zones (Z1 and Z2), 6306 individuals were captured, whereas in the deeper zone (Z3), 3808 specimens were captured, but no significant differences in SL was detected between the specimens from Z1 and Z2 and those from Z3 (ANOVA, p=0.25). The abundance of shrimps did not differ significantly between seasons (Tukey’s test, p=0.02) except in the spring. The sex ratio differed significantly over the seasons (χ², p<0.05). The results were closely associated with environmental factors with respect to the spatial and seasonal distribution of L. faxoni. Rainfall affected salinity directly, and contributed to the displacement of these shrimps to deeper areas.

Reo-Like Virus in White Shrimp Penaeus vannamei (Crustacea: Decapoda): Co-occurrence with Baculovirus penaei in Experimental Infections

A virus, tentatively identified as reo-like, occurred concurrently with experimentally-induced Baculovirus penaei (BP) infection in cultured white shrimp larvae Penaeus vannamei. Each shrimp with a reo-like viral infection also had a BP infection, but not all BP-infected shrimp had a reo-like infection. Both viruses occurred in the same tissues and occasionally withln the same cell. The reolike virus developed in epithelial cells of the anterior midgut and in reserve- and fibrillar-cells of the hepatopancreas. The paraspherical and non-enveloped reo-like virions (ca. 50 nm diam.) occurred as unordered aggregates in the cell cytoplasm. Their etiology has not been determined. Reo-like virions may have been introduced along with the BP virus, or, were latent and only manifested due to stress induced by the more pathogenic BP virus.

Paraophioidina scolecoides n. sp., a New Aseptate Gregarine from Cultured Pacific White Shrimp Penaeus vannamei

The aseptate gregarine Paraophloidina scolecoides n. sp. (Eugregarinorida: Lecudinidae) heavily infected the midgut of cultured larval and postlarval specimens of Penaeus vannamei from a commercial 'seed-production' facility in Texas, USA. It is morphologically similar to P. korotneffi and P. vibiliae, but it can be distinguished from them and from other members of the genus by having gamonts associated exclusively by lateral syzygy. Shrimp acquired the infection at the facility; nauplii did not show any evidence of infection, but protozoea, mysis, and postlarval shrimp had a prevalence and intensity of infection ranging from 56 to 80 % and 10 to >50 parasites, respectively. Infected shrimp removed from the facility to aquaria at another location lost their gamont infection within 7 days When voided from the gut, the gregarine disintegrated in seawater. Results suggest that P. vannamei is an accidental host, although a survey of representative members of the invertebrate fauna from the environment associated with the facility failed to discover other hosts. No link was established between infection and either the broodstock or the water or detritus from the nursery or broodstock tanks.

Relationship Between BP (Baculovirus penaei) Energy Reserves in Larval and Postlarval Pacific White Shrimp Penaeus vannamei

The relationship between energy reserves of the penaeid shrimp Penaeus vannamei and Baculovirus penaei, or BP, were investigated in a series of experiments using mysis stage or early postlarval shrimp. Pre-exposure and post-exposure levels of protein and triacylgycerol (TAG) were determined. The effect of pre-exposure protein and TAG levels on susceptibility to BP infections was also investigated by starving a group of shrimp immediately prior to BP exposure. There was no consistent relationship between either pre-exposure or post-exposure protein levels and the percent of shrimp developing patent BP infections. There was, however, a significant positive correlation between TAG levels immediately prior to viral exposure and prevalence of infection 72 h later. Experimental reduction of TAG reserves prior to BP exposure delayed the development of a patent infection. In some, but not all, experiments there was a significant reduction in TAG levels of infected compared with uninfected shrimp 72 h post-exposure. The effect of patent BP infections on host TAG levels was subordinate to fluctuations in TAG content associated with the ontogeny of the hepatopancreas. Results of this study support histological observations that shrimp lipid levels can be altered by baculovirus infections. Furthermore, high levels of energy reserves in the form of TAG are associated with increased susceptibility to BP infection in larval and postlarval shrimp.

A Filamentous Bacterium on the Brine Shrimp and Its Control

A strain of a colorless, filamentous bacterium (tentatively identified as Leucothrix mucor) heavily infests the brine shrimp, Artemia salina. Its ultrastructure, unlike that of some other strains, does not reveal a distinct middle layer between its outer cell wall layer and cytoplasmic membrane, irregular blebs extending from the cell layers, or an external sheath. An entire infestation, represented as a mat of the bacterium with associated debris and microorganisms, sloughs from the shrimp when exposed to a variety of treatments. Primarily because most effective treatments are toxic to the shrimp, 100 ppm terramycin provides the treatment of choice.

Prediction of apparent protein digestibility of ingredients and diets by in vitro pH-stat degree of protein hydrolysis with species-specific enzymes for juvenile Pacific white shrimp Litopenaeus vannamei

Aquafeed production faces global issues related to availability of feed ingredients. Feed manufacturers require greater flexibility in order to develop nutritional and cost-effective formulations that take into account nutrient content and availability of ingredients. The search for appropriate ingredients requires detailed screening of their potential nutritional value and variability at the industrial level. In vitro digestion of feedstuffs by enzymes extracted from the target species has been correlated with apparent protein digestibility (APD) in fish and shrimp species. The present study verified the relationship between APD and in vitro degree of protein hydrolysis (DH) with Litopenaeus vannamei hepatopancreas enzymes in several different ingredients (n = 26): blood meals, casein, corn gluten meal, crab meal, distiller`s dried grains with solubles, feather meal, fish meals, gelatin, krill meals, poultry by-product meal, soybean meals, squid meals and wheat gluten. The relationship between APD and DH was further verified in diets formulated with these ingredients at 30% inclusion into a reference diet. APD was determined in vivo (30.1 +/- 0.5 degrees C, 32.2 +/- 0.4%.) with juvenile L vannamei (9 to 12 g) after placement of test ingredients into a reference diet (35 g kg(-1) CP: 8.03 g kg(-1) lipid; 2.01 kcal g(-1)) with chromic oxide as the inert marker. In vitro DH was assessed in ingredients and diets with standardized hepatopancreas enzymes extracted from pond-reared shrimp. The DH of ingredients was determined under different assay conditions to check for the most suitable in vitro protocol for APD prediction: different batches of enzyme extracts (HPf5 or HPf6), temperatures (25 or 30 degrees C) and enzyme activity (azocasein): crude protein ratios (4 U: 80 mg CP or 4 U: 40 mg CP). DH was not affected by ingredient proximate composition. APD was significantly correlated to DH in regressions considering either ingredients or diets. The relationships between APD and DH of the ingredients could be suitably adjusted to a Rational Function (y = (a + bx)/(1 + cx + dx2), n = 26. Best in vitro APD predictions were obtained at 25 degrees C, 4 U: 80 mg CP both for ingredients (R(2) = 0.86: P = 0.001) and test diets (R(2) = 0.96; P = 0.007). The regression model including all 26 ingredients generated higher prediction residuals (i.e., predicted APD - determined APD) for corn gluten meal, feather meal. poultry by-product meal and krill flour. The remaining test ingredients presented mean prediction residuals of 3.5 points. A model including only ingredients with APD>80% showed higher prediction precision (R(2) = 0.98: P = 0.000004; n = 20) with average residual of 1.8 points. Predictive models including only ingredients from the same origin (e.g., marine-based, R(2) = 0.98; P = 0.033) also displayed low residuals. Since in vitro techniques have been usually validated through regressions against in vivo APD, the DH predictive capacity may depend on the consistency of the in vivo methodology. Regressions between APD and DH suggested a close relationship between peptide bond breakage by hepatopancreas digestive proteases and the apparent nitrogen assimilation in shrimp, and this may be a useful tool to provide rapid nutritional information. (C) 2009 Elsevier B.V. All rights reserved.

Digestive peptidases and proteinases in the midgut gland of the pink shrimp Farfantepenaeus paulensis (Crustacea, Decapoda, Penaeidae)

Proteases from the midgut gland of the Farfantepenaeus paulensis juveniles were assessed. Enzyme activity was determined using protease substrates and inhibitors. The effect of pH, temperature and calcium on proteolytic activity was assayed. Caseinolytic activity was analysed in substrate-sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Trypsin, chymotrypsin and leucine aminopeptidase activity was detected. Proteolytic activity was strongly inhibited by the specific trypsin inhibitors. Tosyl-phenylalanine chloromethyl ketone inhibited 59.3% of chymotrypsin activity. The greatest trypsin-like activity occurred at pH 8.0 and 45 degrees C. Chymotrypsin-like activity reached maximal values at alkaline pH (7.2-9.0) and 55 degrees C. CaCl(2) did not increase trypsin-like activity, but rather inhibited it at concentrations of 30 (20%), 50 (30%) and 100 mM (50%). The substrate-SDS-PAGE zymogram revealed eight proteinase bands. Two possibly thermal-resistant (85 degrees C, 30 min) chymotrypsin isoforms were found, which were inhibited by phenyl-methyl-sulphonyl-fluoride. Aminopeptidase activity of enzyme extracts (Arg, Leu, Lys, Phe and Val) and the recommended concentrations of these essential amino acids in penaeid shrimp diets were positively correlated (P < 0.05). Beause protein digestion involves the combined action of different enzymes, adequate knowledge of shrimp digestion and enzyme characteristics is required for the assessment of the digestive potential of different feed sources and development of in vitro digestibility protocols.