Home About us Contact
|
Home About us Contact | ||
|
|
||
Shrimp Litopenaeus Vannamei (shrimp + litopenaeu_vannamei)
Kinds of Shrimp Litopenaeus Vannamei Selected AbstractsEffects of Gender and Size on Feed Acquisition in the Pacific White Shrimp Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2006Dustin R. Moss Pacific white shrimp, Litopenaeus vannamei, are sexually dimorphic for growth, where subadult and adult females typically are larger than males of the same age. This character may be attributed to physiological and/or behavioral differences between the sexes. To determine if growth differences are the result of a more aggressive feeding behavior by females, four concurrent feeding trials were conducted to study the effects of gender and size on feed acquisition time. Feeding trials consisted of tanks (three replicate tanks per trial) stocked with (1) all females with small- and large-size groups, (2) all males with small- and large-size groups, (3) a random selection of males and females (resulting in larger females than males), and (4) males and females of equal size. Depending on the trial, tanks were stocked with either an equal number of males and females or small and large shrimp. Shrimp were fed a limited ration of squid, and the total feeding time (TFT) of shrimp between groups within a tank was compared. Results show that both gender and size are important factors in TFT as large shrimp out-competed small shrimp in both all-female and all-male feeding trials. Gender is more important than size as males out-competed females for feed even when they were smaller than competing females. These results suggest that sexual growth dimorphism is not the result of more aggressive feeding by females. In fact, males have a competitive advantage over females in acquiring feed. These results are counterintuitive because females typically are larger than males. Additional research is needed to investigate the physiological basis for sexual growth dimorphism in this commercially important shrimp. [source] Effects of Artificial Substrate and Stocking Density on the Nursery Production of Pacific White Shrimp Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2004Komarey R. K. Moss Nursery production may be enhanced by the addition of artificial substrate to increase the surface area upon which shrimp graze and to serve as refuge. The objective of this study was to assess the effects of the artificial substrate, AquaMatsTM, on the performance of postlarval Pacific white shrimp Litopenaeus vannamei stocked at three densities. Eighteen 230-L tanks were stocked with 10-d postlarvae (mean weight < 0.01 g). Six treatments were evaluated and consisted of shrimp stocked at three densities (778 shrimp/m2, 1,167 shrimp/ m2, and 1,556 shrimp/m2) with and without access to artificial substrate. Shrimp in all treatments received a commercial diet ad libitum. After 6 wk, shrimp were harvested from each nursery tank, counted, and batch weighed. Mean final weight, survival, production, feed conversion ratio, and water quality parameters were analyzed by 2-way ANOVA. There were highly significant (P < 0.001) density and substrate effects on final weight, but there was no significant interaction effect. Final weight was 26.0, 17.4, and 34.5% greater in treatments with substrate than without substrate when stocked at 778, 1,167, and 1,556 shrimp/m2, respectively. There was no significant density, substrate, or interaction effect on survival or water quality. Mean survival was ± 89.1% for all treatments. Increased shrimp growth in the presence of added substrate was likely due to the availability of attached particulate organic matter on the AquaMatsTM that served as an additional food source. Results from this study indicate that artificial substrate can be used to mitigate the potential negative effects of high stocking density on growth of L. vannamei in nursery systems. [source] Effects of Diet and Water Source on the Nursery Production of Pacific White Shrimp Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2001Clete A. Otoshi Penaeid shrimp reared in eutrophic pond water grow significantly faster than shrimp in clear well water, and this growth enhancement is especially pronounced in postlarval shrimp. The objective of this study was to determine if the nutritional benefits of pond water could supplement a lower protein feed for postlarval Pacific white shrimp Litopenaeus vannamei. Sixteen 230-L tanks were stocked with 10-d postlarvae at a density of 350 shrimp/tank. Four treatments (four replicates/treatment) were tested for 6 wk and consisted of: 1) shrimp grown in well water and fed a commercially available 45%-protein feed (W/45); 2) shrimp grown in pond water and fed the same 45%-protein feed (P/45); 3) shrimp grown in well water and fed a commercially available 52%-protein feed (W/ 52); and 4) shrimp grown in pond water and fed the same 52%-protein feed (P/52). At the end of the experiment. mean weight gain (± SE) for shrimp in pond water (1.85 ± 0.03 g) was significantly greater (P > 0.0001) than shrimp in well water (0.98 ± 0.10 g). Mean weight gain for shrimp fed the 52%-protein feed (1.56 ± 0.13 g) was significantly greater (P > 0.0001) than shrimp fed the 45%-protein feed (1.26 ± 0.20 g). In addition, there was a significant interaction effect between water source and feed (P > 0.0001). Mean weight gain for shrimp in the W/52 treatment (1.23 ± 0.04 g) was 68% greater than shrimp in the W/45 treatment (0.73 ± 0.03 g). However, mean weight gain for shrimp in the P/52 treatment (1.90 ± 0.03 g) was only 5% greater than shrimp in the P/45 treatment (1.80 ± 0.04 g). These results suggest that organically rich pond water provides postlarval shrimp with sufficient nutrients to compensate for nutritional deficiencies associated with a lower protein feed. [source] Relative Abundance and Species Composition of Gram-Negative, Aerobic Bacteria Associated with the Gut of Juvenile White Shrimp Litopenaeus vannamei Reared in Oligotrophic Well Water and Eutrophic Pond WaterJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2000Shaun M. Moss Gut bacteria may contribute significantly to the growth and survival of cultured shrimp, although little is known about factors that affect bacterial community structure in shrimp guts. The objective of this study was to determine the abundance and species composition of gut bacteria in juvenile white shrimp Litopenaeus vannamei reared in two different environments. Eight 120-L tanks were stocked at a density of 8 shrimphank. Two treatments were tested for 10 d and consisted of tanks receiving flow-through water from one of two sources: 1) well water pumped from a sea-water aquifer (Well treatment), and 2) pond water pumped from an intensive shrimp pond (Pond treatment). Shrimp mid- and hindguts were excised on days 1, 3, 6, and 10 for enumeration of gram-negative, aerobic bacteria by quantifying colony-forming units (CFU) using standard microbiological plating techniques. Identification of bacterial isolates was made using the Biologa® GN Microplate system. Bacterial numbers were significantly greater (P > 0.05) in Well shrimp than in Pond shrimp on days 1 and 3. Following day 3, a decrease in bacterial numbers occurred in the Well shrimp, and no significant differences between treatments were observed on days 6 or 10. Guts from Well shrimp were dominated by Vibrio and Aero-monas, and these two genera accounted for 80,851 of the bacteria on each sampling day. Guts from Pond shrimp exhibited a greater bacterial diversity and were dominated by Vibrio, Aeromonas, and Pseudomonas. Flavobacterium were identified in the guts of Pond shrimp on days 3 and 10, but were not identified in any of the Well shrimp. A greater understanding of gut bacteria-shrimp interactions could lead to increased production and profitability for shrimp farmers through the development of more cost-effective feeds and novel disease control strategies. [source] Correlation Between Two Size Classes of Pacific White Shrimp Litopenaeus vannamei and Its Potential Implications for Selective Breeding ProgramsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000Brad J. Argue Breeders may assume that the largest brood-stock shrimp were also the largest market shrimp. In this study, 120 market shrimp were individually tagged and grown to broodstock in an earthen pond. There was a significant relationship between market and broodstock weight (P < 0.001) but it was not highly correlated (r = 0.42). There was no correlation between market weight and post-market weight gain (P= 0.477; r= 0.08). Of the largest 20 broodstock, only seven were among the top 20 at market weight. If the goal of a breeding program is to select the fastest growing individuals to market, shrimp should be individually selected at market weight and not as broodstock. [source] Inhibition by Cu2+ and Cd2+ of a mu-class glutathione S-transferase from shrimp Litopenaeus vannameiJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2010Alex J. Salazar-Medina Abstract Glutathione S -transferases (GSTs) are a family of detoxifying enzymes that catalyze the conjugation of glutathione (GSH) to electrophiles, thereby increasing the solubility of xenobiotics and aiding its excretion from the cell. The present work presents the inhibition of a mu-class GST of the marine shrimp Litopenaeus vannamei by copper (Cu2+) and cadmium (Cd2+). The protein was overexpressed in bacteria and its enzymatic activity measured using 1-chloro-2,4-dinitrobenzene. The mean inhibitory concentration (IC50) for shrimp GST against Cu2+ was 4.77 ,M and for Cd2+ was 0.39 ,M. A molecular model of the protein based on the crystal structure of a maize GST bound to cadmium showed that the metal binds in the GSH-binding site by coordination with Asp and Gln residues. These results are consistent with the experimental data and suggest that sublethal concentration of metals may affect the capacity of the organism to detoxify pesticides or xenobiotics. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:218,222, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20326 [source] A Mu-class glutathione S -transferase from gills of the marine shrimp Litopenaeus vannamei: Purification and characterizationJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2007Carmen A. Contreras-Vergara Abstract Glutathione S -transferases (GSTs) are a family of detoxifying enzymes that catalyze the conjugation of glutathione (GSH) to electrophiles, thereby increasing the solubility of GSH and aiding its excretion from the cell. In this study, a glutatione S -transferase from the gills of the marine shrimp Litopenaeus vannamei was purified by affinity chromatography using a glutathione,agarose affinity column. GST was purified to homogeneity as judged by reducing SDS-PAGE and zymograms. This enzyme is a homodimer composed of ,25-kDa subunits and identified as a Mu-class GST based on its activity against 1-chloro-2,4-dinitrobenzene (CDNB) and internal peptide sequence. The specific activity of purified GST was 440.12 ,mol/(min mg), and the Km values for CDNB and GSH are very similar (390 and 335 ,M, respectively). The intersecting pattern of the initial velocities of this enzyme in the Lineweaver,Burke plot is consistent with a sequential steady-state kinetic mechanism. The high specific activity of shrimp GST may be related to a highly effective detoxification mechanism necessary in gills since they are exposed to the external and frequently contaminated environment. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:62,67, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20162 [source] A Methodology for Evaluation of Dietary Feeding Stimulants for the Pacific White Shrimp, Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005Dagoberto R. Sanchez A simple and practical method for quantification of feeding stimulation of shrimp Litopenaeus vannamei was developed using feed preference as an index of comparison. Feed preference was defined as the percentage of shrimp observed in each feeding tray. Preliminary trials were undertaken with two commercial feeds (45% protein with 5% squid meal and 40% protein without squid meal). Results indicated the following criteria were suitable for use as methodology for evaluating feeding stimulation in 5-m diameter static flow tanks: shrimp density (2.5 shrimp/m2); observational period (1 or 2 h post-addition of feed to trays), feed rate (2%), and between-trial feed rate (2%). A further investigation was undertaken to evaluate the influence of protein level and source on feed preference using a basal diet consisting of wheat flour, casein, carboxymethyl cellulose binder, and limestone, with or without krill meal as a feeding stimulant. A significant difference was shown in feeding preference for the 16% protein/4% krill meal vs. one without krill meal; however, this relationship was not shown in 45% protein feed comparisons. A second trial comparing 0, 16,30, and 45 % protein/casein-based feeds showed similar results. From these findings, it was postulated that casein, itself, also serves as a feeding stimulant at high dietary inclusion levels. A third trial comparing 16% protein/casein or wheat gluten-based feeds Indicated a delay of at least 2 h in maximum feeding preference response in feeds in which 4% krill meal was added as a feeding stimulant. It was postulated that chemical stimulants from krill meal were more slowly released in wheat gluten-based feeds. Our methodology appears suitable for evaluation of potential feeding stimulants when incorporated into low-protein casein-based or wheat-gluten-based feeds. [source] Effects of Artificial Substrate and Stocking Density on the Nursery Production of Pacific White Shrimp Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2004Komarey R. K. Moss Nursery production may be enhanced by the addition of artificial substrate to increase the surface area upon which shrimp graze and to serve as refuge. The objective of this study was to assess the effects of the artificial substrate, AquaMatsTM, on the performance of postlarval Pacific white shrimp Litopenaeus vannamei stocked at three densities. Eighteen 230-L tanks were stocked with 10-d postlarvae (mean weight < 0.01 g). Six treatments were evaluated and consisted of shrimp stocked at three densities (778 shrimp/m2, 1,167 shrimp/ m2, and 1,556 shrimp/m2) with and without access to artificial substrate. Shrimp in all treatments received a commercial diet ad libitum. After 6 wk, shrimp were harvested from each nursery tank, counted, and batch weighed. Mean final weight, survival, production, feed conversion ratio, and water quality parameters were analyzed by 2-way ANOVA. There were highly significant (P < 0.001) density and substrate effects on final weight, but there was no significant interaction effect. Final weight was 26.0, 17.4, and 34.5% greater in treatments with substrate than without substrate when stocked at 778, 1,167, and 1,556 shrimp/m2, respectively. There was no significant density, substrate, or interaction effect on survival or water quality. Mean survival was ± 89.1% for all treatments. Increased shrimp growth in the presence of added substrate was likely due to the availability of attached particulate organic matter on the AquaMatsTM that served as an additional food source. Results from this study indicate that artificial substrate can be used to mitigate the potential negative effects of high stocking density on growth of L. vannamei in nursery systems. [source] Effect of Low Salinity on Growth and Survival of Postlarvae and Juvenile Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2001Susan Laramore The effect of low salinity on survival and growth of the Pacific white shrimp Litopenaeus vannamei was examined in the laboratory due to the interest of raising shrimp inland at low salinities. In three separate experiments, individual L. vannamei postlarvae (, 0.1 g) were cultured at salinities of either 0.5, 1, 1.5, 2, or 3 ppt (N= 5 or 10/treatment) for 18 to 40 d at 30 C in individual 360-mL containers. In each experiment controls of 0 and 30 ppt were run. There was no postlarval survival at salinities < 2 ppt. Survival was significantly different (P < 0.01) at 2 ppt (20%) compared to 30 ppt (80%). Growth was also significantly different (P < 0.01) at 2 and 3 ppt compared to 30 ppt (416%, 475%, and 670%, respectively). A fourth experiment compared juveniles (, 8 g) and postlarvae (, 0.05 and 0.35 g). Shrimp were cultured at salinities of 0, 2, 4, and 30 ppt for 40 d at 25 C, in individual 360-mL and 6-L containers (N= 7/treatment). There was no postlarval survival at < 2 ppt. Postlarval survival at 4 ppt (86%) was not significantly different (P > 0.05) from 30 ppt (100%). Juveniles exhibited better survival at lower salinities (100% at 2 ppt) than 0.05 and 0.35 g postlarvae (29% and 14% respectively, at 2 ppt). The effects of salinity on growth varied with sizdage. Final growth of 0.05 g postlarvae at 2 ppt (693%) was significantly less (P < 0.01) than at 4 ppt (1085%) and 30 ppt (1064%). Growth of 0.35 g postlarvae was significantly less (P < 0.01) for 4 ppt (175%) than for 30 ppt (264%). There was no growth data for juveniles (8 g). It appears from these experiments that the culture of L. vannamei poses risks when performed in salinities less than 2 ppt. [source] Effects of Diet and Water Source on the Nursery Production of Pacific White Shrimp Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2001Clete A. Otoshi Penaeid shrimp reared in eutrophic pond water grow significantly faster than shrimp in clear well water, and this growth enhancement is especially pronounced in postlarval shrimp. The objective of this study was to determine if the nutritional benefits of pond water could supplement a lower protein feed for postlarval Pacific white shrimp Litopenaeus vannamei. Sixteen 230-L tanks were stocked with 10-d postlarvae at a density of 350 shrimp/tank. Four treatments (four replicates/treatment) were tested for 6 wk and consisted of: 1) shrimp grown in well water and fed a commercially available 45%-protein feed (W/45); 2) shrimp grown in pond water and fed the same 45%-protein feed (P/45); 3) shrimp grown in well water and fed a commercially available 52%-protein feed (W/ 52); and 4) shrimp grown in pond water and fed the same 52%-protein feed (P/52). At the end of the experiment. mean weight gain (± SE) for shrimp in pond water (1.85 ± 0.03 g) was significantly greater (P > 0.0001) than shrimp in well water (0.98 ± 0.10 g). Mean weight gain for shrimp fed the 52%-protein feed (1.56 ± 0.13 g) was significantly greater (P > 0.0001) than shrimp fed the 45%-protein feed (1.26 ± 0.20 g). In addition, there was a significant interaction effect between water source and feed (P > 0.0001). Mean weight gain for shrimp in the W/52 treatment (1.23 ± 0.04 g) was 68% greater than shrimp in the W/45 treatment (0.73 ± 0.03 g). However, mean weight gain for shrimp in the P/52 treatment (1.90 ± 0.03 g) was only 5% greater than shrimp in the P/45 treatment (1.80 ± 0.04 g). These results suggest that organically rich pond water provides postlarval shrimp with sufficient nutrients to compensate for nutritional deficiencies associated with a lower protein feed. [source] Relative Abundance and Species Composition of Gram-Negative, Aerobic Bacteria Associated with the Gut of Juvenile White Shrimp Litopenaeus vannamei Reared in Oligotrophic Well Water and Eutrophic Pond WaterJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2000Shaun M. Moss Gut bacteria may contribute significantly to the growth and survival of cultured shrimp, although little is known about factors that affect bacterial community structure in shrimp guts. The objective of this study was to determine the abundance and species composition of gut bacteria in juvenile white shrimp Litopenaeus vannamei reared in two different environments. Eight 120-L tanks were stocked at a density of 8 shrimphank. Two treatments were tested for 10 d and consisted of tanks receiving flow-through water from one of two sources: 1) well water pumped from a sea-water aquifer (Well treatment), and 2) pond water pumped from an intensive shrimp pond (Pond treatment). Shrimp mid- and hindguts were excised on days 1, 3, 6, and 10 for enumeration of gram-negative, aerobic bacteria by quantifying colony-forming units (CFU) using standard microbiological plating techniques. Identification of bacterial isolates was made using the Biologa® GN Microplate system. Bacterial numbers were significantly greater (P > 0.05) in Well shrimp than in Pond shrimp on days 1 and 3. Following day 3, a decrease in bacterial numbers occurred in the Well shrimp, and no significant differences between treatments were observed on days 6 or 10. Guts from Well shrimp were dominated by Vibrio and Aero-monas, and these two genera accounted for 80,851 of the bacteria on each sampling day. Guts from Pond shrimp exhibited a greater bacterial diversity and were dominated by Vibrio, Aeromonas, and Pseudomonas. Flavobacterium were identified in the guts of Pond shrimp on days 3 and 10, but were not identified in any of the Well shrimp. A greater understanding of gut bacteria-shrimp interactions could lead to increased production and profitability for shrimp farmers through the development of more cost-effective feeds and novel disease control strategies. [source] Comparison of Ulva clathrata and the kelps Macrocystis pyrifera and Ascophyllum nodosum as ingredients in shrimp feedsAQUACULTURE NUTRITION, Issue 4 2009L.E. CRUZ-SUÁREZ Abstract Three experimental diets were formulated to contain 33 g kg,1 seaweed meals, made of wild brown algae (kelps) Macrocystis pyrifera (MAC) and Ascophyllum nodosum (ASC) or of a cultivated green alga Ulva clathrata (ULVA). The diets were fed to juvenile white shrimp Litopenaeus vannamei (1.6 g) for 28 days. Loss of dry matter (LDM) and loss of protein (LP) after 1 hour immersion in seawater, and distilled water absorption (WA) were analyzed in the pelleted diets, as well as shrimp weight gain, feed intake, feed conversion ratio (FCR), survival, protein efficiency ratio (PER) and body pigmentation. Feed intake, FCR and PER were corrected for nutrients preprandial losses in seawater. ULVA diet resulted in lower LDM, but a higher LP and also higher WA, indicating a modification of the pellet physical quality (better hydro stability). No significant differences in feed consumption and survival were found, but ULVA diet resulted in a slightly higher final weight (4.8 for ULVA versus 4.6 and 4.3 g for ASC and MAC), and better FCR (1.7 versus 1.9 and 2.1) and PER (2.0 versus 1.7 and 1.5), the differences with MAC diet being significant (Duncan, , = 0.05). Red color after cooking was markedly darker in the ULVA fed shrimp. [source] Accumulation of heavy metals and total phosphorus in intensive aquatic farm sediments: comparison of tilapia Oreochromis niloticus×Oreochromis aureu, Asian seabass Lates calcarifer and white shrimp Litopenaeus vannamei farmsAQUACULTURE RESEARCH, Issue 9 2010Xiao-Yi Wu Abstract This paper compares and discusses the accumulation of eight heavy metals (Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn) and total phosphorus (TP) in surface sediments from five intensive farms of tilapia Oreochromis niloticus×Oreochromis aureu, Asian seabass Lates calcarifer and white shrimp Litopenaeus vannamei (n=75). Results indicate that the sediments were significantly contaminated by Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn as well as P. The mean concentrations of Cd (0.47 mg kg,1), Co (2.25 mg kg,1), Cu (31.56 mg kg,1), Pb (23.45 mg kg,1), Fe (1.15%), Mn (145.5 mg kg,1), Zn (41.5 mg kg,1) and TP (750.69 mg kg,1) in tilapia farm surface sediments were significantly lower than the levels observed in Asian seabass and white shrimp farm surface sediments, where the concentrations were, respectively, Cd , 2.69 and 2.35 mg kg,1, Co , 17.66 and 15.22 mg kg,1, Cu , 116.84 and 110.03 mg kg,1, Pb , 38.5 and 33.26 mg kg,1, Fe , 3.4% and 3.31%, Mn , 853.61 and 728.5 mg kg,1, Zn , 105.21 and 83.92 mg kg,1 and TP , 1445.63 and 1069.8 mg kg,1. The heavy metal content of the sediments follow the order: Asian sea bass>white shrimp>tilapia. Cadmium and Cu in Asian seabass and white shrimp farm sediments would pose a major potential risk. Further, the sediment is highly enriched by Fe, P, Mn and Co. [source] Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimp Litopenaeus vannameiAQUACULTURE RESEARCH, Issue 7 2010Tzachi M Samocha Abstract Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA-supplemented diet to 5 g and then switched them to a HUFA-supplement-free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA- and ArA-rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei. [source] Activity pattern of the marine shrimp Litopenaeus vannamei (Boone 1931) in laboratory as a function of different feeding frequenciesAQUACULTURE RESEARCH, Issue 1 2009Patrícia Pereira De Lima Abstract Management practices on most Brazilian shrimp farms have resulted in high expenses for producers and damage to the environment. Applied ethology could provide information on the pattern of shrimp activity, enabling more efficient feeding frequencies. Behavioural activities of the shrimp Litopenaeus vannamei were recorded during different feeding frequencies. The shrimp were kept in aquariums on a 12:12 h light/dark cycle. They were fed commercial ration three (at 6:00, 12:00 and 18:00 hours), four (at 6:00, 10:00, 14:00 and 18:00 hours) or seven times per day (at 6:00. 8:00, 10:00, 12:00, 14:00, 16:00 and 18:00 hours). We observed animals at 15 min,1 aquarium,1 time periods, recording feeding, substrate exploration, swimming and inactivity. Feeding and exploration were the highest for shrimp fed three times per day, swimming was greatest when animals received four feedings, whereas inactivity was higher for shrimp fed seven times per day. There was greater food ingestion between 12:00 and 14:00 hours for animals fed three and four times per day, whereas swimming was high mainly at 18:00 hours for shrimp fed three and seven times per day. The results indicate higher forage-related activities (exploration/ingestion) when feed was offered three or four times, suggesting optimization in the pattern of shrimp activities based on these feeding frequencies. [source] Apparent digestibility of selected feed ingredients for white shrimp Litopenaeus vannamei, BooneAQUACULTURE RESEARCH, Issue 1 2009Qihui Yang Abstract Apparent digestibility coefficients of dry matter (DM), crude protein, crude lipid, gross energy, phosphorus and amino acids in Peruvian fish meal (FM), fermented soybean meal, extruded soybean meal, soybean meal, peanut meal, wheat gluten meal, corn gluten meal, shrimp byproduct meal, meat and bone meal (MBM), poultry meat meal and plasma protein meal (PPM) were determined for white shrimp (Litopenaeus vannamei). A reference diet (RF) and test diets (consisting of 70% RF diet and 30% of the feedstuff) were used with 0.5% chromic oxide as an external indicator. A total of 1440 shrimp (initial mean body weight 1.05 ± 0.01 g) were randomly stocked into thirty-six 500-L fibreglass tanks with 40 shrimp per tank and three tanks per diet. Faeces were collected from triplicate groups of shrimp by a faecal collection vessel attached to the shrimp-rearing tank. The shrimp were fed to apparent satiation four times a day and the feeding experiment lasted for 6 weeks. Statistics indicate that apparent DM digestibilities for white shrimp (L. vannamei) were the highest for FM, ranged 52.83,71.23% for other animal products and 69.98,77.10% for plant products. The protein and lipid from plant and animal sources were well digested by white shrimp. Apparent protein and lipid digestibility were in the range 87.89,93.18% and 91.57,95.28%, respectively, in plant products, and 75.00,92.34% and 83.72,92.79%, respectively, for animal products. The white shrimp demonstrated a high capacity to utilize phosphorus in the ingredients. The apparent phosphorus digestibility ranges of animal feedstuffs and plant feedstuffs were 58.90,71.61% and 75.77,82.30% respectively. Amino acid availability reflected protein digestibility, except that in MBM, for which the availability of some amino acid was lower, possibly due to protein damage during processing. Digestibility information could promote the use of ingredient substitution in least-cost formulated diets for white shrimp. [source] Effect of diets containing different levels of highly unsaturated fatty acids on physiological and immune responses in Pacific whiteleg shrimp Litopenaeus vannamei (Boone) exposed to handling stressAQUACULTURE RESEARCH, Issue 16 2009Laurence Mercier Abstract Juveniles fed a diet containing a low or a high level of highly unsaturated fatty acids (HUFA) for 38 days were exposed to handling stress. In a first experiment, stress was applied daily for 30 days, after which the physiological and immunological variables were measured, whereas in a second experiment, stress was applied once and samples were obtained 1 and 24 h after the stressor event. Shrimp that were stressed for 30 days showed significantly lower survival, final weight and feed consumption compared with unstressed shrimp. The concentration of the high-density lipoprotein ,-glucan-binding protein was significantly higher in shrimp fed the high-HUFA diet. The glucose concentration in the haemolymph was significantly higher in long-term stressed shrimp compared to controls. The lactate level in the haemolymph was significantly lower in shrimp fed the high-HUFA diet. Lactate and glucose in the haemolymph increased in the 1-h stressed shrimp, but returned to normal levels in 24-h stressed shrimp. A negative effect of repeated-handling stress applied for 30 days was mainly observed on biological performance, whereas the single-stressor event had a more pronounced effect on shrimp physiological and immune responses measured 1 and 24 h after the stressor. A beneficial role of enrichment with HUFA on tolerance to handling stress was observed on immune response capacity. [source] Quantitative dietary threonine requirement of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone) reared in low-salinity waterAQUACULTURE RESEARCH, Issue 8 2009Ming-Yan Huai Abstract An 8-week feeding trial was conducted to determine the threonine requirement of juvenile Pacific white shrimp Litopenaeus vannamei (Boone) in low-salinity water (0.50,1.50 g L,1). Diets 1,6 were formulated to contain 360 g kg,1 crude protein with fish meal, wheat gluten and pre-coated crystalline amino acids with six graded levels of l -threonine (9.9,19.0 g kg,1 dry diet). Diet 7, which was served as a reference, contained only intact proteins (fish meal and wheat gluten). Each diet was randomly assigned to triplicate groups of 30 shrimps (0.48±0.01 g), each four times daily. Shrimps fed the reference diet had similar growth performance and feed utilization efficiency compared with shrimps fed the diets containing 13.3 g kg,1 or higher threonine. Maximum specific growth rate (SGR) and protein efficiency ratio were obtained at 14.6 g kg,1 dietary threonine, and increasing threonine beyond this level did not result in a better performance. Body compositions, triacyglycerol and total protein concentrations in haemolymph were significantly affected by the threonine level; however, the threonine contents in muscle, aspartate aminotransferase and alanine aminotransferase activities in haemolymph were not influenced by the dietary threonine levels. Broken-line regression analysis on SGR indicated that optimal dietary threonine requirement for L. vannamei was 13.6 g kg,1 dry diet (37.8 g kg,1 dietary protein). [source] Cage culture of the Pacific white shrimp Litopenaeus vannamei (Boone, 1931) at different stocking densities in a shallow eutrophic lakeAQUACULTURE RESEARCH, Issue 2 2009Maria Lourdes A Cuvin-Aralar Abstract Postlarvae of Litopenaeus vannamei were acclimated and stocked in lake-based cages at the following stocking densities: 10, 20, 30 and 40 shrimp m,2. Another set of shrimp was stocked in concrete tanks as reference samples at 30 shrimp m,2. Significant differences were observed among stocking densities throughout the 95-day culture. The final weight at harvest decreased with increasing stocking density: mean weights of 23.3, 15.8, 13.0, 10.9 and 14.6 g for the 10, 20, 30, 40 shrimp m,2 and reference tanks were observed respectively. There were no significant differences in survival throughout the culture period, ranging between 69% and 77%. Daily growth rates (range: 0.11,0.24 g day,1) and specific growth rates (range: 3.54,4.34%) also differed significantly among stocking densities, both increasing with decreasing stocking density. The feed conversion ratio in the cages did not differ among the stocking densities, ranging from 1.53 to 1.65. The relationship between stocking density and mean individual weight at harvest followed the equation y=81.06x,0.54 (R2=0.938) and that of stocking density and production (in g m,2) is y=58.01x,0.46 (R2=0.834). [source] Determination of microbial community structures of shrimp floc cultures by biomarkers and analysis of floc amino acid profilesAQUACULTURE RESEARCH, Issue 2 2008Zhi Yong Ju Abstract Simple, rapid and reliable methods are required to monitor the microbial community change in aquatic pond for better animal performance. Four floc (suspended organic matter) samples were collected from outdoor raceways and tanks used for culturing Pacific white shrimp Litopenaeus vannamei. Twenty-two chlorophyll (Chl) and carotenoid pigments were separated, identified and quantified using high-performance liquid chromatography,ultraviolet/Vis-mass spectrometry in the freeze-dried floc samples. Algal community composition (diatoms, chlorophytes, cyanobacteria, dinoflagellates and cryptophytes) was determined by measuring concentrations of the respective taxonomic biomarkers (carotenoid fucoxanthin, lutein, zeaxanthin, peridinin and alloxanthin) as independent variables and Chl a as the dependent variable using a multiple regression model. This analysis found that the phytoplankton community of the floc samples from two groups of shrimp tanks (32 g L,1 -salinity) were diatom-dominated (81.7% and 84.4%); and two floc samples from shrimp raceways (5 and 18 g L,1 -salinity) were chlorophyte-dominated (75.4% and 82.3%). Assessment of total algal and bacterial biomass by quantification of Chl a and muramic acid, respectively, indicated that the 18 g L,1 -salinity raceway sample was bacteria-dominated, whereas the other three floc samples were algae-dominated. Sample protein quality was evaluated by its essential amino acid (AA) score and index. Arginine and lysine were found to be the two most limiting AAs for all floc samples. [source] Stocking strategies for production of Litopenaeus vannamei (Boone) in amended freshwater in inland pondsAQUACULTURE RESEARCH, Issue 1 2008Bartholomew W Green Abstract The performance of the Pacific white shrimp Litopenaeus vannamei (Boone) under various stocking strategies was evaluated in earthen ponds filled with freshwater amended with major ions. Six 0.1-ha earthen ponds located in Pine Bluff, AR, USA, were filled with freshwater in 2003 and 2004, and potassium magnesium sulphate added to provide 50 mg K+ L,1 and stock salt added to provide 0.5 g L,1 salinity. In 2003, three ponds either were stocked with PL15 shrimp (39 PL m,2) for 125 days of grow out or with PL25 shrimp for 55 days (23 PL m,2) followed by a 65-day (28 PL m,2) grow-out period. In 2004, ponds were stocked with 7, 13 or 30 PL15 m,2 for 134 days of grow out. Salinity averaged 0.7 g L,1 during both years, and concentration of SO4,2, K+, Ca2+ and Mg2+ was higher, and Na+ and Cl, was lower in amended pond water than in seawater at 0.7 g L,1 salinity. Potassium concentration in amended water was 52,61% of the target concentration. Shrimp yields ranged from 3449 kg ha,1 in 2003 to 4966 kg ha,1 in 2004 in ponds stocked with 30,39 PL15 m,2 for a 125,134-day culture period. At harvest, mean individual weight ranged from 17.1 to 19.3 g shrimp,1. In ponds stocked with PL25 shrimp, yields averaged 988 and 2462 kg ha,1 for the 1st and 2nd grow-out periods respectively. Gross shrimp yield in 2004 increased linearly from 1379,4966 kg ha,1 with increased stocking rate. These experiments demonstrated that L. vannamei can be grown successfully in freshwater supplemented with major ions to a final salinity of 0.7 g L,1. [source] Preliminary evaluation of a purified nucleotide mixture as a dietary supplement for Pacific white shrimp Litopenaeus vannamei (Boone)AQUACULTURE RESEARCH, Issue 8 2007Peng Li First page of article [source] Environmental sex determination, external sex differentiation and structure of the androgenic gland in the Pacific white shrimp Litopenaeus vannamei (Boone)AQUACULTURE RESEARCH, Issue 15 2006Rafael Campos-Ramos Abstract Environmental effects on sex determination in Litopenaeus vannamei were studied by rearing day 1 postlarvae at three temperatures, under three photoperiods, at high density and by starving. None of the environmental conditions affected sex determination or differential development of gender in this species. From day 50, the development of the endopodite of the first pair of pleopods revealed the first external differentiation, showing a triangular structure with three setae in females, whereas a tubular structure remained in males. Juvenile shrimp sex differentiation took place from days 50,90, independent of size, only if postlarvae reached a development threshold of 150 mg of body weight and 20 mm of body length previously. Histology and scanning electron microscopy of the vas deferens revealed that the androgenic gland (AG) is a single 2-mm cord attached in the subterminal ejaculatory region, just before the distal vas deferens narrows. The AG is composed of large oval cells containing vacuolated cytoplasm, and each cell has a prominent rounded nucleus, similar to all descriptions of the AG in Malacostracans, so we assume that it should have the same function in sex differentiation. [source] Effect of dietary protein and energy levels on growth, oxygen consumption, haemolymph and digestive gland carbohydrates, nitrogen excretion and osmotic pressure of Litopenaeus vannamei (Boone) and L. setiferus (Linne) juveniles (Crustacea, Decapoda; Penaeidae)AQUACULTURE RESEARCH, Issue 7 2001C Rosas 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,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,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,1 (27% protein; 32% carbohydrate) and L. vannamei between 26 and 36 mg kJ,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,1 diet and lower values (O/N = 73) with a 36-mg kJ,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,1 and the lowest in L. vannamei <,1 g fed with 31 mg kJ,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. [source] | ||||||||||