Search

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Atlantic white shrimp (Litopenaeus setiferus) is of great economic importance to the United States and risk being substituted with imported species due to a shortage in domestic production. To improve the current methods used for the identification of the Atlantic white shrimp species, we designed and validated a robust multiplex PCR-lateral flow assay for the onsite identification of L. setiferus. The standardized assay was validated using a miniaturized, low-cost PCR instrument with 68 shrimp, prawn, and fish samples, spread over fourteen seafood species. L. setiferus was simultaneously amplified by the multiplex assay to give three visual bands, which distinguished it from other species having either one or two bands on the dipstick. The standardized assay showed 100% inclusivity for target L. setiferus samples, 100% exclusivity for non-target samples and can be completed in less than two hours. The assay standardized in this study can be used for onsite testing of L. setiferus samples at processing facilities, restaurants, and wholesalers' facilities.

This study evaluated the effect of biofloc technology (BFT) at 3 (lsBFT) and 35 (hsBFT) practice salinity units (psu) on the zootechnical performance, oxygen consumption, antioxidant activity, and oxidative damage of Litopenaeus setiferus juveniles reared in outdoor tanks. After 90 days, no significant differences were observed in terms of survival (p >.05). The final weight as well as wet weight gain, final biomass, and feeding conversion ratio (FCR) showed higher values for shrimp reared with hsBFT than those reared with lsBFT (p <.05). Compared to that for the hsBFT treatment, high oxygen consumption (VO2) was observed for the lsBFT treatment under fasting and postprandial conditions (p <.05). The activity of the enzymes catalase, superoxide dismutase, and glutathione‐S‐transferase from shrimp muscle did not show significant differences between the treatments (p >.05). Regarding the lipid peroxidation (LPO) and oxidized protein (PO) in muscle samples, no significant differences were observed in LPO, whereas the PO was significantly higher for the lsBFT treatment (p <.05), which was related to higher fasting and postprandial oxygen consumption of the juveniles (p <.05). The adaptation of L. setiferus juveniles reared in BFT at low salinity is relatively weak because of their low growth and excessive oxygen consumption and the oxidative damage (PO) produced. [ABSTRACT FROM AUTHOR]

Chemical pesticides are commonly used world-wide, and they can flow into estuaries and affect non-targeted organisms. We evaluated the effects of six concentrations of the phenylpyrazole, fipronil (0.0, 0.005, 0.01, 0.1, 1.0, and 3.0 μg/L), which are environmentally relevant, on white shrimp Litopenaeus setiferus (initially averaging 0.80 ± 0.08 g/shrimp). Compared with the control, survivorship of shrimp over 45 days declined significantly at the higher concentration treatments. Growth was affected at all concentrations, and the percent weight gain decreased significantly. Inter-molt intervals were longer in all treatments. Changes in swimming and feeding behavior of shrimp were observed under all treatments, and change in body color was observed at higher concentration treatments. Lipid content in shrimp decreased significantly while ash content increased with fipronil concentration. Fipronil adversely affected white shrimp under the concentrations observed in the environment and monitoring of fipronil use is needed in coastal areas. [ABSTRACT FROM AUTHOR]

White shrimps, Litopenaeus setiferus (Linnaeus, 1767) and pink shrimps, Farfantepenaeus duorarum (Burkenroad, 1939) are two pivotal species in the southern Gulf of Mexico, due to their ecological and economic importance. In this study we present observational evidence of the seasonal and interannual variability of both species in the Términos Lagoon (southern Gulf of Mexico). The results suggest that the hydrography of the water column and the surface circulation exert a strong influence on the density of both species. The results presented here contribute to a better understanding of the dynamics of both species and highlight the need to combine different methodologies to achieve a better interpretation of this system. Resumen: El camarón blanco, Litopenaeus setiferus (Linnaeus, 1767) y el camarón rosado, Farfantepenaeus duorarum (Burkenroad, 1939) son dos especies fundamentales en el sur del Golfo de México, debido a su importancia ecológica y económica. En este estudio presentamos evidencia observacional de la variabilidad estacional e interanual de ambas especies en la Laguna de Términos (sur del Golfo de México), mostrando que la hidrografía de la columna de agua y el patron de circulación superficial ejercen una fuerte influencia en la densidad de ambas especies. Los resultados aquí presentados contribuyen a una mejor comprensión de la dinámica de ambas especies y resaltan la necesidad de combinar diferentes metodologías para lograr una mejor interpretación del sistema. [ABSTRACT FROM AUTHOR]

Litopenaeus setiferus has been described as an economically important native species ranging from the north Atlantic along the coast of the Gulf of Mexico to Florida. Its reproduction has been studied in captivity, as well as some aspects of its nutritional physiology, diseases and adaptation to various environments, including nurseries. In terms of growth, L. setiferus has been compared with L. vannamei for its performance in ponds. As a native species, L. setiferus benefits local fisheries and is also used as a bait shrimp for recreational activity. The present review covers background information and recent advances in research and development efforts to determine its potential both for aquaculture in ponds and intensive biofloc systems (BFT), as well as for the stocking of fishing grounds. The collective research advances for this species presented in this review could help to sustain various strategies, including highly intensive techniques, to rehabilitate L. setiferus in connection with potential institutes. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the spatial and seasonal concentrations of Cd, Cu, Fe, Ni and Pb in water, sediment and edible muscle of white shrimp (Litopenaeus setiferus) from the estuarine ecosystem Tigre River-San Andres Lagoon (Gulf of Mexico), while assessing the potential human health risk of metals due to shrimp consumption. Most metal concentrations in water, sediment and shrimp muscle changed significantly among seasons. However, differences among sites were only detected for Fe and Cu in sediment. Except for Cd, all metals in water, showed concurrently the highest concentrations in spring. The bioaccumulation factor (BAF) for most metals in shrimp muscle was usually low (i.e. <1) with exception of Cu, whose values ranged from 4.16 to 15.97. On the other hand, the target hazard quotient (THQ) for individual metals and total target hazard quotient (TTHQ) for all metals analyzed were lower than 1, suggesting that metal exposure via consumption of shrimp from the study area does not represent a potential health risk during a person lifetime. Additionally, target carcinogen risk (TCR) estimated from the intake of Pb through consumption of shrimp was 6.1×10-7, indicating negligible carcinogenic risks for consumers. [ABSTRACT FROM AUTHOR]

The development of shrimp aquaculture in Mexican coasts of the Gulf of Mexico began to be explored using the Pacific white shrimp Litopenaeus vannamei in the mid 90´s. Many concerns over the risk of disease transmission to the economically important native penaeids, have been the main deterrent for the aquaculture of L. vannamei in the region. Concurrently, more than 10 years of research experience on the aquaculture suitability of the native Litopenaeus setiferus from the Terminos Lagoon, in the Yucatán Peninsula, have been accumulated. The aim of this study was then to determine the seasonal variations of the naturally acquired diseases and the possible detection of exotic pathogens. For this, random subsamples (n~60) of juveniles L. setiferus were collected from monthly captures. In order to detect the widest range of pathogens, including infectious hypodermal and hematopoietic necrosis (IHHNv) and white spot syndrome (WSSv) viruses, both histopathological and molecular methods were employed. Monthly prevalence (%) was calculated for every finding. We were able to detect a total of 16 distinct histological anomalies, most of which the presump- tive aetiological agent was readily identified. PCR results for viruses were negative. For some pathogens and symbionts, the prevalence was significantly different between the adult and juvenile populations. Prevalence of diseases tended to be higher in juvenile shrimp than in adults. The results of this study indicated that L. setiferus carry a wide variety of pathogens and symbionts that seem to be endemic to penaeids of the Gulf of Mexico, and those juveniles were more conspicuous to acquire pathogens and symbionts than adults.

Changes in freshwater inflow and salinity patterns may affect the nursery value of estuarine systems for penaeid shrimp, but the relationship between salinity and shrimp abundance is complex and likely confounded by other environmental variables. Laboratory experiments can provide insights into salinity selection, and we designed an experimental gradient tank to examine salinity preferences of juvenile brown shrimp and white shrimp. Our design uses gently flowing water to eliminate various physical constraints often associated with selection experiments. We conducted experiments with juvenile brown shrimp (12 trials) and white shrimp (seven trials), to examine selection for salinities along a gradient from 1 to 42. Data were analyzed using contingency tables and log-linear modeling to examine relationships with salinity and possible interactions with temperature. Both brown shrimp and white shrimp were present in all salinities examined within the experimental range. In general, brown shrimp showed a preference for salinities from 17 to 35 and demonstrated avoidance for the extreme low salinities along the gradient. Results for white shrimp were not statistically significant, and this species did not appear to avoid low salinities. There was no effect of water temperature on the observed selection patterns for brown or white shrimp. Our results suggest that although salinity preferences likely exist for these species, strong distribution trends associated with salinity gradients in estuaries are likely caused by other environmental factors. [ABSTRACT FROM AUTHOR]

The Atlantic white shrimp ( Litopenaeus setiferus ) is of great economic importance to the United States and risk being substituted with imported species due to a shortage in domestic production. To improve the current methods used for the identification of the Atlantic white shrimp species, we designed and validated a robust multiplex PCR-lateral flow assay for the onsite identification of L. setiferus . The standardized assay was validated using a miniaturized, low-cost PCR instrument with 68 shrimp, prawn, and fish samples, spread over fourteen seafood species. L. setiferus was simultaneously amplified by the multiplex assay to give three visual bands, which distinguished it from other species having either one or two bands on the dipstick. The standardized assay showed 100% inclusivity for target L. setiferus samples, 100% exclusivity for non-target samples and can be completed in less than two hours. The assay standardized in this study can be used for onsite testing of L. setiferus samples at processing facilities, restaurants, and wholesalers' facilities., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Prashant Singh has patent Methods and compositions useful in discriminating between fish species pending to Florida State University.]., (© 2023 The Author(s).)

Since June 2012, samples of wild caught white shrimp, Litopenaeus setiferus, from the Gulf of Mexico, Plaquemines and Jefferson Parishes (Louisiana, USA) with clinical signs of microsporidiosis have been delivered to the Louisiana Aquatic Diagnostic Laboratory for identification. Infection was limited predominantly to female gonads and was caused by a microsporidium producing roundish pansporoblasts with eight spores (3.6 × 2.1 μm) and an anisofilar (2–3 + 4–6) polar filament. These features allowed identification of the microsporidium as Agmasoma penaei Sprague, 1950. Agmasoma penaei is known as a microsporidium with world-wide distribution, causing devastating epizootic disease among wild and cultured shrimps. This paper provides molecular and morphological characterisation of A. penaei from the type host and type locality. Comparison of the novel ssrDNA sequence of A. penaei from Louisiana, USA with that of A. penaei from Thailand revealed 95% similarity, which suggests these geographical isolates are two different species. The A. penaei sequences did not show significant homology to any other examined taxon. Phylogenetic reconstructions using the ssrDNA and alpha- and beta-tubulin sequences supported its affiliation with the Clade IV Terresporidia sensu Vossbrink 2005, and its association with parasites of fresh and salt water crustaceans of the genera Artemia , Daphnia and Cyclops . [ABSTRACT FROM AUTHOR]

Marsh shoreline, an important habitat for juvenile penaeid shrimps, was extensively oiled in coastal Louisiana by the Deepwater Horizon oil spill of 2010. The effect of this spill on growth was examined for brown shrimp Farfantepenaeus aztecus and white shrimp Litopenaeus setiferus held for 7 days in field mesocosms in Barataria Bay during May and August 2011, respectively. The experiments each had 10 treatment combinations, five apparent oil levels, each one with and without added food. Mesocosms were placed in northern Barataria Bay along shorelines that varied in oiling (designated as heavy, moderate, light, very light, or none based on NOAA surveys), and shrimp in half the mesocosms received additional food. Polycyclic aromatic hydrocarbon (PAH) concentrations determined from sediment cores collected at each mesocosm were significantly higher at heavy and moderate than very light shorelines and also higher at moderate than light and none shorelines. Brown shrimp grew more slowly at heavy than very light or none shorelines, and a statistically significant negative relationship was detected between brown shrimp growth rates and sediment PAH concentrations. In August, PAH sediment concentrations had decreased significantly from the values measured in May, no significant difference in white shrimp growth rates was detected among oiling levels, and no relationship was detected between white shrimp growth and sediment PAH concentrations. Both brown shrimp and white shrimp grew more rapidly in mesocosms where food was added. Our study shows that exposure to nonlethal concentrations of petroleum hydrocarbons can reduce growth rates of juvenile penaeid shrimps. [ABSTRACT FROM AUTHOR]

This study presents an Ex-Post Facto analysis of diseases of wild juvenile and adults of Litopenaeus setiferus collected from a field survey at the Natural Protected Area of Terminos lagoon, southern Mexico. The objective of the present approach was to determine if sampling site and/or shrimp age were contributing risk factors for disease between juvenile and adult shrimp; if there was a determined period of time in a year cycle when diseases were more critical, and if the analysis would help to decision- making considering what population would pose less risk of disease-carrying when withdrawn for experimental purposes; all under an after-the-fact ( ex-post facto) approach. We identified that juvenile shrimp were at more risk of contracting some diseases in the estuarine environment and June, July and August months, were found to be a critical period when colonizing and parasitic diseases maintained a significant high prevalence in the shrimp population. These assumptions may help for decision-making when wild shrimp have to be withdrawn from their natural environment for research purposes. [ABSTRACT FROM AUTHOR]

The development of shrimp aquaculture in Mexican coasts of the Gulf of Mexico began to be explored using the Pacific white shrimp Litopenaeus vannamei in the mid 90's. Many concerns over the risk of disease transmission to the economically important native penaeids, have been the main deterrent for the aquaculture of L. vannamei in the region. Concurrently, more than 10 years of research experience on the aquaculture suitability of the native Litopenaeus setiferus from the Terminos Lagoon, in the Yucatán Peninsula, have been accumulated. The aim of this study was then to determine the seasonal variations of the naturally acquired diseases and the possible detection of exotic pathogens. For this, random subsamples (n~60) of juveniles L. setiferus were collected from monthly captures. In order to detect the widest range of pathogens, including infectious hypodermal and hematopoietic necrosis (IHHNV) and white spot syndrome (WSSV) viruses, both histopathological and molecular methods were employed. Monthly prevalence (%) was calculated for every finding. We were able to detect a total of 16 distinct histological anomalies, most of which the presumptive aetiological agent was readily identified. PCR results for viruses were negative. For some pathogens and symbionts, the prevalence was significantly different between the adult and juvenile populations. Prevalence of diseases tended to be higher in juvenile shrimp than in adults. The results of this study indicated that L. setiferus carry a wide variety of pathogens and symbionts that seem to be endemic to penaeids of the Gulf of Mexico, and those juveniles were more conspicuous to acquire pathogens and symbionts than adults. [ABSTRACT FROM AUTHOR]

Hepatopancreatic brush border membrane vesicles (BBMV), made from Atlantic White shrimp ( Litopenaeus setiferus), were used to characterize the transport properties of H- l-leucine influx by these membrane systems and how other essential amino acids and the cations, sodium and potassium, interact with this transport system. H- l-leucine uptake by BBMV was pH-sensitive and occurred against transient transmembrane concentration gradients in both Na- and K-containing incubation media, suggesting that either cation was capable of providing a driving force for amino acid accumulation. H- l-leucine uptake in NaCl or KCl media were each three times greater in acidic pH (pH 5.5) than in alkaline pH (pH 8.5). The essential amino acid, l-methionine, at 20 mM significantly ( p < 0.0001) inhibited the 2-min uptakes of 1 mM H- l-leucine in both Na- and K-containing incubation media. The residual H- l-leucine uptake in the two media were significantly greater than zero ( p < 0.001), but not significantly different from each other ( p > 0.05) and may represent an l-methionine- and cation-independent transport system. H- l-leucine influxes in both NaCl and KCl incubation media were hyperbolic functions of [ l-leucine], following the carrier-mediated Michaelis-Menten equation. In NaCl, H- l-leucine influx displayed a low apparent K (high affinity) and low apparent J, while in KCl the transport exhibited a high apparent K (low affinity) and high apparent J. l-methionine or l-phenylalanine (7 and 20 mM) were competitive inhibitors of H- l-leucine influxes in both NaCl and KCl media, producing a significant ( p < 0.01) increase in H- l-leucine influx K, but no significant response in H- l-leucine influx J. Potassium was a competitive inhibitor of sodium co-transport with H- l-leucine, significantly ( p < 0.01) increasing H- l-leucine influx K in the presence of sodium, but having negligible effect on H- l-leucine influx J in the same medium. These results suggest that shrimp BBMV transport H- l-leucine by a single l-methionine- and l-phenylalanine-shared carrier system that is enhanced by acidic pH and can be stimulated by either Na or K acting as co-transport drivers binding to shared activator sites. [ABSTRACT FROM AUTHOR]

Abstract: Selective tidal-stream transport is commonly used by marine animals to migrate between oceanic and estuarine habitats as they undergo ontogenetic migrations, but behaviors used to accomplish these migrations may differ among species, life history stages, or locations. The ecologically and commercially important brown shrimp, Farfantepenaeus aztecus, pink shrimp, Farfantepenaeus duorarum, and white shrimp, Litopenaeus setiferus, undergo ontogenetic migrations between spawning locations on the continental shelf and juvenile nursery habitats in estuaries. This study evaluated the role of endogenous rhythms in vertical swimming activity in Flood Tide Transport (FTT) of postlarvae entering estuaries and the potential for shifts in behavior between the postlarval and juvenile stages. Brown and pink shrimp postlarvae exhibited circatidal rhythms in vertical swimming activity with period lengths of approximately 12.4h that coincided with the time of early flood tide in the field, whereas white shrimp postlarvae did not exhibit an endogenous rhythm in swimming activity. Pink shrimp juveniles (20-40mm total length) exhibited a distinct circadian activity rhythm with a mean period length of 23.8±3.7h and peak swimming during the time of night in the field. Juvenile brown and white shrimp exhibited relatively weak circatidal activity rhythms with peak vertical swimming around the times of ebb and early flood tide in the field, respectively. These results suggest that 1) brown and pink shrimp postlarvae exhibited endogenous activity rhythms that would enhance FTT, 2) white shrimp postlarvae likely depend on environmental cues associated with flood tide to accomplish FTT, and 3) pink shrimp are unique among these three species in exhibiting a shift from a circatidal to a nocturnal swimming activity rhythm between postlarval and juvenile stages. [Copyright &y& Elsevier]

The effects of sodium, potassium, sugar inhibitors, and membrane potential on H- d-glucose uptake by hepatopancreatic epithelial brush border membrane vesicles (BBMV) of the Atlantic marine shrimp, Litopenaeus setiferus, were investigated. Brush border membrane vesicles were prepared using a MgCl/EGTA precipitation method and uptake experiments were conducted using a high speed filtration technique. H- d-Glucose uptake was stimulated by both sodium and potassium and these transport rates were almost doubled in the presence of an inside-negative-induced membrane potential. Kinetics of H- d-glucose influx were hyperbolic functions of both external Na or K, and an induced membrane potential increased influx J and lowered K in both salts. H- d-Glucose influx versus [glucose] in both Na or K media also displayed Michaelis-Menten properties that were only slightly affected by induced membrane potential. Phloridzin was a poor inhibitor of 0.5 mM H- d-glucose influx, requiring at least 5 mM in NaCl and 10 mM in KCl to significantly reduce hexose transport. Several sugars ( d-galactose, α-methyl- d-gluco-pyranoside, unlabeled d-glucose, d-fructose, and d-mannose) were used at 75 mM as potential inhibitors of 0.1 mM H- d-glucose influx. Only unlabeled d-glucose, d-fructose, and d-mannose significantly ( p < 0.05) reduced labeled glucose transport. An additional experiment using increasing concentrations of d-mannose (0, 10, 25, 75, and 100 mM) showed this hexose to be an effective inhibitor of 0.1 mM H- d-glucose uptake at concentrations of 75 mM and higher. As a whole these results suggest that H- d-glucose transport by hepatopancreatic BBMV occurs by a carrier system that is able to use both Na and K as drivers, is enhanced by membrane potential, is relatively refractory to phloridzin, and is only inhibited by itself, d-fructose, and d-mannose. These properties are similar to those exhibited by the mammalian SLC5A9/SGLT4 transporter, suggesting that an invertebrate analogue of this protein may occur in shrimp. [ABSTRACT FROM AUTHOR]

Purified epithelial brush border membrane vesicles (BBMV) were produced from the hepatopancreas of the Atlantic White shrimp, Litopeneaus setiferus, using standard methods originally developed for mammalian tissues and previously applied to other crustacean and echinoderm epithelia. These vesicles were used to study the cation dependency of sugar and amino acid transport across luminal membranes of hepatopancreatic epithelial cells. H- d-glucose uptake by BBMV against transient sugar concentration gradients occurred when either transmembrane sodium or potassium gradients were the only driving forces for sugar accumulation, suggesting the presence of a possible coupled transport system capable of using either cation. H- l-histidine transport was only stimulated by a transmembrane potassium gradient, while H- l-leucine uptake was enhanced by either a sodium or potassium gradient. These responses suggest the possible presence of a potassium-dependent transporter that accommodates either amino acid and a sodium-dependent system restricted only to l-leucine. Uptake of H- l-leucine was significantly stimulated ( P < 0.05) by several metallic cations (e.g., Zn, Cu, Mn, Cd, or Co) at external pH values of 7.0 or 5.0 (internal pH 7.0), suggesting a potential synergistic role of the cations in the transmembrane transfer of amino acids. H- l-histidine influxes (15 suptakes) were hyperbolic functions of external [zinc] or [manganese], following Michaelis-Menten kinetics. The apparent affinity constant (e.g., K) for manganese was an order of magnitude smaller ( K = 0.22 μM Mn) than that for zinc ( K = 1.80 μM Zn), while no significant difference ( P > 0.05) occurred between their maximal transport velocities (e.g., J). These results suggest that a number of cation-dependent nutrient transport systems occur on the shrimp brush border membrane and aid in the absorption of these important dietary elements. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the presence of protozoan and metazoan parasites, as well as white spot syndrome virus (WSSV) and infectious hypodermal hematopoietic necrosis virus (IHHNV) in the white shrimp Litopenaeus setiferus and the palaemonid prawn Macrobrachium acanthurus. The shrimps are native to the lower Jamapa River region of Veracruz, Mexico. The viruses in the shrimps were detected through the use of polymerase chain reaction (PCR). The study was conducted at the Tecnológico de Boca del Río in Veracruz.

Abstract: Freshwater inflows from river diversions may affect nekton populations by altering the salinity and temperature of estuarine waters. To investigate the influence of these environmental variables on the growth and survival rates of brown shrimp Farfantepenaeus aztecus and white shrimp Litopenaeus setiferus, we conducted field experiments in May and September 2007 to expose experimental animals to the range of different combinations of salinity and water temperature that commonly occur in an estuarine environment. Growth rates for shrimp held in mesocosms for approximately 7days were compared among four locations and three treatments; locations were identified by the dominant marsh vegetation and distance from the Gulf of Mexico (low to high salinity: Intermediate, Brackish, Saline UE=Saline Up Estuary, Saline DE=Saline Down Estuary). At each location, the treatments were replicated four times and included shallow water with additional food, shallow water without food added, and deeper water (an attempt to expose animals to lower temperatures). Our experiments were designed to test the null hypothesis that shrimp growth and survival rates did not differ by location or treatment. Both brown shrimp and white shrimp grew more slowly at the Intermediate than higher salinity locations. Potential prey (benthic infauna) biomass was relatively low at both the Intermediate and Brackish locations in May, and both shrimp species consistently grew faster in mesocosms where food was added. We conclude that reduced growth in low salinity environments is likely due to the combined effects of increased metabolic costs and less food in these areas. River diversions that reduce estuarine salinities over a large portion of available habitat during peak recruitment periods may reduce overall growth rates and shrimp productivity in the affected areas. [ABSTRACT FROM AUTHOR]

Abstract: In order to identify the specific role of humoral lectins in crustaceans'' immune response, we evaluated the effect of the 291 kDa hemocyanin-like lectin from Litopenaeus setiferus (LsL) on its own hemocytes. LsL binds 5.6% of circulating non-activated hemocytes, but is able to recognize 85% of total adhered (activated) hemocytes, showing filipodia and pseudopodia, inducing the production of reactive oxygen intermediates (ROIs) in a time- and dose-dependent manner (100 ng/105 cells/20 min). This effect was inhibited specifically by N-acetylated sugars (NeuAc, GalNAc or GlcNAc), as well as by superoxide dismutase (SOD), acetylsalicylic, and mefenamic acid. In hemocytes, LsL also induced higher ROIs production than Zymozan (p >0.05). The receptor for LsL in the hemocytes membrane is a glycoprotein of 61 and 52 kDa per subunit, as determined by western blot. Our results suggest that LsL participates in the activation of oxidative immune responses of granular hemocytes induced by NADPH and other oxidative pathways through a specific membrane receptor. [Copyright &y& Elsevier]

Abstract: Macrobenthic invertebrates are an important food source for higher trophic levels in freshwater and marine habitats, yet the importance of predation impacting regular seasonal changes in macrobenthos abundance remains unclear. Benthic invertebrates and transient marine species in temperate estuaries display inverse patterns of seasonal abundance, suggesting a link between predation and summer macrobenthos abundance minima. We conducted manipulative caging experiments to test the importance of predation by white shrimp (Litopenaeus setiferus) in regulating estuarine subtidal macrobenthos densities. We predicted greater declines in macrobenthos densities with increased shrimp densities due to predation rather than disturbance and macrobenthos emigration. Using these field and laboratory data, we estimate whether white shrimp predation can significantly contribute to the macrobenthos seasonal abundance minima observed in long-term monitoring data. White shrimp predation was measured in the field using 7-d predator enclosure/exclusion experiments. Within the uppermost 0–2 cm of sediment, total macrobenthos densities decreased within shrimp enclosure cages using 12 or 36 shrimp m−2. Laboratory experiments distinguished between the effects of shrimp predation versus shrimp disturbance and macrobenthos emigration. Shrimp predation significantly reduced macrobenthos densities, while effects of shrimp disturbance and macrobenthos emigration were not significant in these experiments. Despite the impacts from other ambient predators and other abiotic factors, white shrimp were clearly capable of driving subtidal macrobenthos from their annual maximum density in winter/spring to their summertime minimum density. [Copyright &y& Elsevier]

Abstract: The pharmacokinetics of the antibiotic, oxytetracycline (OTC), were examined following oral dosing in the white shrimp, Litopenaeus setiferus. These studies were conducted to improve dosing efficacy and safety for OTC use in treating shrimp. Oxytetracycline is available commercially for feed preparation as a premix of two different forms of the parent drug, the dihydrate form (OXTC) and the monoalkyl (C8-18) trimethyl quaternary salt form (TMF). Both pharmacokinetics and physicochemical properties were studied under conditions simulating a marine environment. Physicochemical properties studied were solubility and short-term stability of the premixes and dissolution following incorporation of the premix into feed. The oral bioavailability of OTC from feed containing either form of OTC was evaluated and compared in shrimp following single and multiple dosing. Hemolymph levels of OTC at predetermined time intervals after dosing were measured by High Performance Liquid Chromatography (HPLC). The hemolymph OTC levels were fitted to appropriate pharmacokinetic models to determine parameters as is typically done in pharmacokinetic evaluations. OTC was more than twice as soluble from OXTC than from the TMF premix. After being pelleted with feed, dissolution studies showed nearly identical release profiles for the two OTC forms. It appears that the medicated feed acts like a matrix resulting in a controlled release dosage form for OTC with 100% release requiring about 24 h. The short-term stability study indicated that OTC from the TMF premix was more stable than OXTC in seawater under ambient conditions. While this might improve bioavailability and therapeutic efficacy, it will lengthen its residence time in the environment if released with consequent increased environmental risk. Hemolymph OTC concentration versus time profiles following single dose oral administration were well described by a triexponential equation suggesting a two compartment pharmacokinetic model. OTC was well absorbed from both salt forms when orally administered; bioavailability was better than reported in the literature for finfish. To evaluate bioequivalency, the rate and extent of absorption were compared for the two forms of OTC. The maximum hemolymph concentration (C max) and time to achieve the maximum (t max) were not significantly different for the two forms, but the apparent bioavailability (F) and area under the concentration–time curve (AUC) was found to be statistically greater for the OXTC form. In both cases, peak concentrations were delayed, suggesting a unique mechanism for absorption in shrimp. While single dose studies with individual shrimp suggested that OXTC was the preferred form of OTC, multiple dose studies with multiple shrimp showed that practically there is little difference in therapeutic efficacy or depuration times between the two forms of OTC. Overall, either form of OTC can be useful for the aquaculturing of shrimp; it appears that OTC can be used safely in a product for human consumption following a reasonably short withdrawal period. [Copyright &y& Elsevier]

Abstract: A 291-kDa lectin (LsL) was purified from the hemolymph of the white shrimp Litopenaeus setiferus by affinity chromatography on glutaraldehyde-fixed stroma from rabbit erythrocytes. LsL is a heterotetramer of two 80-kDa and two 52-kDa subunits, with no covalently-liked carbohydrate, and mainly composed by aspartic and glutamic acids, glycine and alanine, with relatively lower methionine and cysteine contents. Edman degradation indicated that the NH2-terminal of the 80-kDa subunit is composed DASNAQKQHDVNFLL, whereas the NH2-terminal of the 52-kDa subunit is blocked. The peptide mass fingerprint of LsL was predicted from tryptic peptides from each subunit by MALDI-TOF, and revealed that each subunit showed 23 and 22%, respectively, homology with the hemocyanin precursor from Litopenaeus vannamei. Circular dichroism analysis revealed beta sheet and alpha helix contents of 52.7 and 6.1%, respectively. LsL agglutinate at higher titers guinea pig, murine, and rabbit erythrocytes its activity is divalent cation-dependent. N-acetylated sugars, such as GlcNAc, GalNAc, and NeuAc, were the most effective inhibitors of the LsL hemagglutinating activity. Sialylated O-glycosylated proteins, such as bovine submaxillary gland mucin, human IgA, and fetuin, showed stronger inhibitory activity than sialylated N-glycosylated proteins, such as human orosomucoid, IgG, transferrin, and lactoferrin. Desialylation of erythrocytes or inhibitory glycoproteins abolished their capacity to bind LsL, confirming the relevance of sialic acid in LsL–ligand interactions. [Copyright &y& Elsevier]

Abstract: A cDNA clone coding for a Kazal protein was isolated from a cDNA library of Litopenaeus vannamei hemocytes. The full-length cDNA sequence is 1.32kb long and encodes a 24kDa protein. Four Kazal domains, 43–46 residues long, were detected in the deduced primary structure. Apparently, the first and second domains do not have inhibitory activity, as predicted by the sequence between the second and third Cys. The third and fourth domains have the sequences CPEIYAPVC and CPKNYRPVC, indicating that they are able to inhibit subtilisin- and trypsin-like proteins, respectively. mRNA Levels of the shrimp Kazal protein were modified after injection of Vibrio alginolyticus, suggesting a probable role in the immune response. [Copyright &y& Elsevier]

Abstract: Several investigations have demonstrated that the increase in chemicals in the environment may have caused effects on aquatic life and wildlife. The impact from oil production activities on the benthic community structure and shrimp (Farfantepenaeus duorarum and Litopenaeus setiferus) biochemical markers were studied in the Gulf of Mexico, which is heavily contaminated by polycyclic aromatic hydrocarbons and heavy metals. Shrimp were collected from a control area and from an area close to oil production platforms during October and November 2002. There was no spatial difference in exposure and response probably because shrimp migrate, as results did not show significant differences in cytochrome P4501A (as measured by ethoxycoumarin O-deethylase (ECOD) metabolism) between the two sites. In October, shrimp ECOD activities were higher and statistically different from those measured in the samples taken in November. As for ECOD activities, with the concentration of vitellogenin as another biomarker, there were no differences between the shrimp collected from the control area and the shrimp collected on the oil production platforms. In this case the concentrations were higher in shrimp collected in November vs. shrimp collected in October. However, there are significant correlations between contaminants and responses (biomarkers), indicating an effect of pollution. One of the most important considerations brought up by this kind of study is that, although the majority of groups studying the effects of endocrine disruption have focused almost exclusively on human health or vertebrate wildlife-related issues, it is necessary to increase research focused on understanding the function of hormones in invertebrate species exposed in the field to different kinds of pollutants. [Copyright &y& Elsevier]

The amounts of energy channeled into growth (P), maintenance (R), excretion (U) and exuviae (Ev) were quantified in six dietary treatments during early postlarval development in Litopenaeus setiferus and Litopenaeus vannamei reared at 28±1 °C and 35±1‰ salinity. The six diet combinations were: (1) freshly hatched Artemia nauplii, (2) freshly hatched Artemia nauplii supplemented with algae, (3) microparticulate commercial diet (MCD), (4) MCD supplemented with algae, (5) Artemia nauplii partially substituted (50%) by MCD and (6) Artemia nauplii partially substituted (50%) by MCD supplemented with algae. Oxygen consumption, ammonia excretion and dry weight were measured from postlarvae day 1 (PL1) to PL10 (1 to 10 days after metamorphosis). Energy distribution in both species was affected by diet with significantly higher proportion of energy allocated into production (1.49 J day-1 for L. setiferus and 1.77 J day-1 for L. vannamei) when animals were fed a mixed diet. The proportion of assimilated energy channeled into production (P/As) was greater when both species were fed mixed diet and was lower when fed on MCD alone or MCD plus algae. On the contrary, the proportion of assimilated energy used in respiration (R/A) was higher for both species when fed on MCD alone or MCD plus algae, with the lowest values in animals fed on the mixed diet. Low values of net growth efficiency (K2) were found in both species when the main food was MCD (alone or supplemented with algae), with the highest K2 when animals were fed the mixed diet. Results show that divergences between these two species during early postlarval stages only appear when animals were in a poor physiological condition due to an inefficient diet. Artemia nauplii, partially substituted by MCD with a supplement of algae, integrated a high-quality diet for both species producing high net growth efficiency. [Copyright &y& Elsevier]

Shrimp are among the most highly valued seafood in the US, and a large proportion are cultured. At least seven species of Vibrio bacteria and other pathogens often infect shrimp during some stage of culture, having profound impacts on productivity. The research described herein was conducted to optimize dosing to allow effective disease control while minimizing environmental residues. Pharmacokinetics of oxytetracycline (OTC), a broad spectrum antibiotic were evaluated in the white shrimp, Litopenaeus setiferus, to characterize its disposition and to determine its potential for use in farm-raised shrimp for the treatment of Vibrio infections. Intravascular dosing and sampling techniques were developed, since this was the first pharmacokinetic study in shrimp using survival sampling. Pharmacokinetics of OTC were evaluated after single low and high bolus intravascular doses and hemolymph sampling. Tissue distribution was investigated after systemic administration, and protein binding was studied in hemolymph isolated from shrimp using ultrafiltration. The hemolymph and tissue levels of OTC were measured by HPLC and fitted to appropriate pharmacokinetic models to characterize the disposition of OTC in shrimp. Hemolymph OTC concentration–time profiles were well described by a biexponential equation indicative of two-compartment pharmacokinetics of OTC in shrimp. The half-lives of distribution and elimination were 2.05±0.48 and 22.27±7.45 h, respectively. Systemic clearance and steady-state volume of distribution were 78.04±24.33 ml/h/kg and 2304±280 ml/kg, respectively. OTC levels in tail muscle (% of total body burden) were significantly lower than in hemolymph, minimizing concerns of OTC residue in edible shrimp tissue after OTC treatment. Hemolymph protein binding of OTC was found to be low with almost 80% free OTC available systemically, supporting the high volume of distribution observed. Despite the simple anatomy, small size and short life span of shrimp, the disposition of OTC in shrimp after intravascular dosing showed pharmacokinetic characteristics indicative of extensive tissue distribution, such as a long elimination half-life and a high volume of distribution, with the low potential for OTC residues in tail muscle tissue. Our results suggest that shrimp given a therapeutic dose of OTC (i.e., sufficient to exceed the MIC) will have no detectable OTC levels in edible tissues 14 days following withdrawal. However, the salt form and formulation of OTC in feeds can impact dissolution, bioavailability, pharmacokinetics and, hence, tissue residues. Thus, withdrawal times should not be drug or agent specific but product and formulation specific. These results must be confirmed with oral dosing studies and bioavailability determinations that are underway in our laboratory. [Copyright &y& Elsevier]

Size-selective predation by small (30-50 mm carapace width) and large (90-110 mm) Callinectes sapidus when feeding on three different size classes of Litopenaeus setiferus was investigated. Laboratory experiments using no-choice and multiple-choice designs were carried out. Active and passive components of predation were evaluated by comparing the probability of attacking (active) and capturing (passive) shrimp. Small C. sapidus consumed shrimp of all size classes in similar frequencies during multiple and no-choice experiments, and the probability of attacking and capturing shrimp of all size classes was similar. Large crabs consumed large shrimp with a significantly higher frequency during multiple than during no-choice experiments, and the probability of capturing large shrimp was significantly higher than medium and small ones. Results in the present study suggest that size-specific consumption rates of C. sapidus are mainly the result of a passive mechanism associated with the salience of shrimp to predation. However, an active component of foraging behaviour related to the decision to attack an alternative prey whilst consuming one that has already been captured, helps to explain the differences in shrimp consumption between multiple and no-choice experiments. The complex interaction between active, passive components and satiation is discussed. [ABSTRACT FROM AUTHOR]

Abstract The white shrimp (Litopenaeus setiferus ) is a commercially and recreationally valuable species, yet little is known of its population structure or genetic diversity. White shrimp are distributed along the Atlantic coast of the United States and from the west coast of Florida to the Bay of Campeche, Mexico. In this study, shrimp were collected from North Carolina, South Carolina (four separate collections were taken from 1995 to 1999), Georgia, the Atlantic and Gulf coasts of Florida, Louisiana, Texas and Mexico. DNA was isolated from these individuals, and genetic variation was assessed at six microsatellite loci. These loci were, for the most part, highly polymorphic with an average expected heterozygosity of 0.68. Deviations from Hardy–Weinberg proportions were observed over all samples, but experimental results suggested the presence of null alleles, which confounded a biological interpretation of this result. Pairwise tests of the similarity of allele frequency distributions and distance measure analyses showed broad-scale genetic homogeneity superimposed over occasional indications of random geographical and temporal differentiation. F [sub ST] and R [sub ST] estimates over all loci and samples were 0.002 or less and indicated little population structure. Weak but significant genetic differentiation was evident only between pooled western Atlantic and pooled Gulf of Mexico samples. Within the Gulf of Mexico or within the western Atlantic, the large-scale genetic homogeneity observed may be a consequence of genetic mixing resulting from pelagic larvae and adult migrations, while the random local genetic differentiation may be a result of genetic sampling or experimental sampling error. The weak differentiation between shrimp from the Gulf of Mexico and the western Atlantic can be explained by a relatively recent separation of these two populations and/or small amounts of ongoing gene flow. [ABSTRACT FROM AUTHOR]

This study deals with some aspects about the influence of partially substituting the traditional food given to shrimp for Artemia franciscana adults. It was seen that the biomass of A. franciscana fed with Spirulina maxima benefits L. setiferus female maturation (eggs/spawning), when used as substitute for the 10% daily ration of traditional feed. Substitution of 11% of A. franciscana in the daily ration of fresh feed in L. schmitti increased the number of matings/maturation tanks/day. This biomass of A. franciscana resulted in a 3.5 increase in L. schmitti matings, compared to the matings observed in the control group or in animals fed at 22 and 33% levels. The possible complementation of fresh food with live Artemia biomass is proposed as an option to improve maturation and increase mating in controlled conditions. [ABSTRACT FROM AUTHOR]

Abstract The influence of protein and energy levels on growth rate, survival, pre- and post-prandial oxygen consumption, ammonia excretion, haemolymph glucose (HG), glycogen in digestive gland and osmotic pressure (OP) in white shrimp Litopenaeus vannamei (Boone) and L. setiferus (Linne) juveniles was studied. Diets containing a high-quality protein at a protein/energy (P/E) ratio of 16, 26, 31 and 36 mg kJ[sup -1] were fed at 20% of shrimp body weight of two sizes: < 1 g and > 1 g. Both species showed a optimum P/E ratio of 36 mg kJ[sup -1] (33–44% protein and 6–23% carbohydrate) in juveniles < 1 g. For shrimp > 1 g, L. setiferus showed a higher growth rate in the diet with 16 mg kJ[sup -1] (27% protein; 32% carbohydrate) and L. vannamei between 26 and 36 mg kJ[sup -1] (33–44% protein and 6–23% carbohydrate). In both experiments, the growth rate of L. vannamei was 2–3 times that observed in L. setiferus. Routine oxygen consumption and apparent heat increment (AHI) of L. setiferus juveniles was two times higher than that observed in L. vannamei juveniles, which could indicate that L. setiferus has a higher metabolic rate. The O/N ratio varied according to protein level, with higher values (O/N = 180) with a 16-mg kJ[sup -1] diet and lower values (O/N = 73) with a 36-mg kJ[sup -1] diet in L. setiferus juveniles. A similar variation in O/N ratio was obtained in L. vannamei fed with all diets with an interval between 22 and 50. An inverse relation between ammonia excretion and HG, and digestive gland glycogen (DGG) in relation to an increase in the P/E ratio indicate that both shrimp species are well adapted to use carbohydrates and/or proteins from their diet. The higher values of hyper-osmotic capacity (hyper-OC) were observed in L. setiferus < 1 g fed with 36 mg kJ[sup -1] and the lowest in L. vannamei < 1 g fed with 31 mg kJ[sup -1]. Intermediate values of hyper-OC were observed in both species fed all diets indicating that osmotic factors of juveniles < 1 g of both species are more affected by the P/E ratio than juveniles > 1 g. All results showed that juveniles > 1 g of both species are less dependent of P/E ratio than juveniles < 1 g. Litopenaeus vannamei is a most tolerant shrimp species with a high capacity to use a wide range of dietary P/E ratios for growth, which may be due to its lower energy requirements. Litopenaeus setiferus showed a lower capacity to accept different P/E ratios but the optimum P/E ratio obtained with this species shows that L. setiferus accept diets with a high carbohydrate level as well. These results demonstrate that there are nutritional and physiological differences that explain the differences that have been observed when both species were cultured in commercial ponds. [ABSTRACT FROM AUTHOR]