Enriched Artemia with L-lysine and DL-methionine on growth performance,stress resistance,and fatty acid profile of Litopenaeus vannamei postlarvae

A 15-day study was conducted to evaluate the effect of enrichment of Artemia metanauplii with four different emulsions, including: (A) Easy-DHA Selco; (B) Easy-DHA Selco + L-lysine (4 g/L); (C) Easy-DHA Selco + DL-methionine (4 g/L); and (D) Easy-DHA Selco + L-lysine (2 g/L) + DL-methionine (2 g/L) on growth and stress resistance of white leg shrimp Litopenaeus vannamei larvae (from Mysis I to postlarvae12). It is noticed that shrimp PL in group B had the highest wet (36.1 ± 3.1 mg) and dry (1116.7 ± 60.0 µg) weights as well as stress resistance to fresh water (64.0 ± 5.5%).     

Effects of different feed management treatments on water quality for Pacific white shrimp Litopenaeus vannamei

Increasing feeding rates may provide an increase in production, thus nutrients such as nitrogen, phosphorus and organic matter will also increase. These nutrients promote a greater oxygen demand and concentrations of toxic metabolites which can lead to frequent problems with low dissolved oxygen and an abundance of blue‐green algae. Four feed management practices were evaluated among sixteen 0.1 ha ponds culturing Pacific white shrimp (Litopenaeus vannamei). Feeding treatments included hand feeding using the Standard Feeding Protocol (SFP), SFP plus 15% from 8 to 16 weeks, an automatic‐solar timer which fed SFP+15%, and an AQ1 acoustic demand feeder allowing up to 12 kg/day·pond based on shrimps feeding response. Samples were analysed at weeks 0, 4 and 8–16 for the following parameters: chlorophyll a, total ammonia nitrogen, nitrite–nitrogen, nitrate–nitrogen, total nitrogen, total phosphorus, soluble reactive phosphorus, total suspended solids, total suspended volatile solids, turbidity, conductivity, salinity and biological oxygen demand. Samples were collected and shipped overnight to Auburn, Alabama for off‐site analysis. On‐site water quality was also obtained at the farm. The AQ1 acoustic demand feeder produced the most shrimp with a yield of 4,568 kg/ha; however, the AQ1 also had the highest total ammonia nitrogen and nitrite–nitrogen levels late in the growing season. The AQ1 feeder may be a viable, reduced labour and cost alternative for the shrimp commercial industry; however, such technologies must also be matched to the ability of the production system to process nutrients.     

Format and mode of artificial substrate fixation affect the performance of Litopenaeus vannamei in high‐density rearing systems

We investigated whether the positive impacts of artificial substrates on shrimp performance are altered in any way by their format or mode of fixation in the tanks. To examine this question, substrates were fixed vertically in the water column in three different configurations: SCF treatment (Substrate Completely Fixed), SPF treatment (Substrate Partially Fixed) and SFF (Substrate in Frond Format). Another treatment received no substrate and served as control (WS = Without Substrate). The shrimp were cultured for 38 days in intensive biofloc culture tanks at a stocking density of 1,125 shrimp m^?3. In general, water quality variables were similar among treatments and remained within the appropriate range for shrimp culture. The final biomass was higher (8.5 kg m^?3) and the feed conversion ratio (FCR) lower (1.6) in all tanks with substrates when compared with the WS treatment tanks (final biomass = 6.3 kg m^?3 and FCR = 3.1). However, only shrimp from the SCF and SPF treatments had a higher survival rate (>95.0%) compared to those in WS tanks (75.9%), which was statistically similar to the SFF treatment (88.0%). These results show that substrate format and its mode of fixation in tanks can alter shrimp performance. In well‐aerated intensive tanks, substrates in frond format are constantly pushed to the tank surface, making it difficult for shrimp to adhere to the screens. In such situation, the extra surface provided by the substrates is not always available to the shrimp, a fact that minimizes the positive effects of substrate.     

Effect of Dietary Supplementation of Brewer's Yeast and GroBiotic®-A on Growth,Immune Responses,and Low-Salinity Tolerance of Pacific White Shrimp Litopenaeus vannamei Cultured in Recirculating Systems

Two separate trials were conducted in clean recirculating systems at salinities of 32.9 (optimal) and 2 ppt (low-salinity challenge) to evaluate brewer's yeast and GroBiotic®-A, a commercial prebiotic, as dietary supplements for growth and health management of Pacific white shrimp Litopenaeus vannamei. The growth-promoting influences of brewer's yeast or GroBiotic®-A previously observed with fish were not demonstrated in these trials with shrimp, when each component was supplemented at 2% or 5% of the diet. No significant dietary effects on hematological and immunological responses—including total hemocyte count, hemolymph protein, phenoloxidase, hemocyte respiratory burst, and clearance efficiency of Vibrio harveyi—were observed in shrimp cultured at full strength salinity (30 ppt) in feeding trial 1 after a 10 week period. In a second feeding trial, dietary supplementation of GroBiotic®-A improved survival of shrimp cultured at low-salinity (2 ppt). Although the mechanism(s) for enhanced survival under low-salinity conditions by dietary immunostimulants or prebiotics have not been identified, these observations indicate potential use of prebiotics such as GroBiotic®-A for shrimp cultured in less than optimal environments.     

Production of Tiger Shrimp (Penaeus monodon) in Potassium Supplemented Inland Saline Sub-Surface Water

Abstract

Potassium deficient inland saline (10 g L^?1 salinity) well water was supplemented with muriate of potash to achieve 50% (57 mg L^?1) and 100% (114 mg L^?1) of seawater potassium concentration and used for the production of tiger shrimp (Penaeus monodon). Total mortality was observed in non-supplemented water within 6 days compared to 88.0% survival in K⁺100% and 85.3% survival in K⁺50% up to 60 days. P. monodon were subsequently cultured for 110 days in two identical 0.25-ha ponds supplied with water of 10 g L^?1 and supplemented with the potassium equivalent of 35% of seawater. Survival and production were 55.8% to 64.25% and 157.70 kg (630.8 kg ha^?1) to 172.75 kg (691 kg ha^?1), respectively.     

Effect of Diet Size on Feeding Behavior and Growth of Pacific White Shrimp,Litopenaeus vannamei

Abstract

Six diet sizes, manufactured from crumbling large pellets, were investigated for their effect on the feeding behavior and growth of Pacific white shrimp, Litopenaeus vannamei. These diets containing 44.7% protein and 8.2% lipid were fed to 0.9 g shrimp for a period of eight weeks under indoor controlled laboratory conditions. Shrimp were stocked at a density of 12 animals per 52 L aquarium (50/m²) and were evaluated for feeding behavior, final weight, growth rate, feed conversion ratio (FCR), and survival. Feeding behavior was observed weekly starting at the beginning of the 4th week until the end of the trial. Results indicated that the variation in diet sizes did not produce significant differences in shrimp growth, FCR or survival. However, shrimp feeding behavior (in terms of total attacking incidents during feeding) was significantly different among diet sizes. This shrimp behavior was observed more frequently in aquaria fed larger diet size (3.0 mm pellet) as compared with those fed smaller diet sizes (0.7 mm and 1.2 mm crumbles). When shrimp were fed larger pellets, some of the individuals obstruct other individuals and monopolize the diet. Such “selfish” behavior of shrimp could result in considerable size variation and severe mortality of smaller individuals, which could be the case when shrimp are reared to market size. The effect of diet size on shrimp feeding behavior deserves further investigation and the use of a continuous monitoring device such as a video camera is strongly recommended. Future study should also consider various shrimp and pellet sizes more meaningful to aquaculture producers.     

The Effect of Potassium Concentration in Inland Saline Water on the Growth and Survival of the Western King Shrimp,Penaeus latisulcatus Kishinouye, 1896

Abstract

The survival, growth, and condition of the western king shrimp, Penaeus latisulcatuswere measured for 42 days when grown in marine water and inland saline water with four different concentrations of potassium: 100%, 80%, 60% or 40% of the concentration of potassium in marine water (IS100, IS80, IS60, and IS40). Shrimp survival and cannibalism frequency decreased with decreasing potassium concentration, with final shrimp survival in IS100 significantly higher (P < 0.05) than in IS60 and IS40 and significantly higher (P < 0.05) in MW and IS80 than in IS40. Specific growth rate (SGR), moult increment, and diet ingestion rate of shrimp were significantly higher (P < 0.05) in shrimp grown in marine water than the other water types. At the conclusion of the trial, exoskeleton mineral content of shrimp in IS100 and IS80 was significantly higher (P < 0.05) than in IS60 and IS40. Tail muscle moisture content of shrimp in IS60 and IS40 was significantly higher (P < 0.05) than in the other water types, suggesting a depletion of tail muscle energy reserves in IS60 and IS40. This trial demonstrates the necessity of fortifying potassium-deficient inland saline water to allow the culture of western king shrimp. Furthermore, a potassium concentration greater than approximately 76% of that in marine water and a Na/K ratio of less then 39 appear to be necessary to maintain a comparable level of shrimp survival, as in marine water. However, the slower growth and reduced molt increment of shrimp in inland saline water with 100% and 80% potassium compared to shrimp in marine water demonstrates the presence of other limiting factors.     

Instrumental Textural Changes in Raw White Shrimp During Iced Storage

The general objective of this work was to evaluate the changes in the texture of raw white shrimp, stored whole in ice for up to 14 days, by instrumental texture analysis of the flesh after peeling off the carapace. Effect of test method (relaxation, compression, texture profile analysis, cutting, and penetration tests), test speed (0.1, 0.5, and 1.0 mm/s), and test position on sample (second, third, and fourth segments of abdominal musculature) were studied to measure the textural attributes of shrimp. Mechanical parameters (force at yield point, stiffness, toughness, and shear/penetration work) increased significantly during the 14 days of storage. Shrimp muscle maintained firm texture up to 4 days of storage after harvesting. At that time, the texture became soft, stiffness of the skin layer increased, and then pH values in the shrimp reached a value higher than 7 (alkaline). A linear model with a high coefficient of determination (R² > 0.75, for all parameters obtained from the penetration test with the spherical probe) described adequately the mechanical properties of iced shrimp during storage. Comparing several methods, the penetration test on the second flesh segment using a spherical probe at a speed of 0.1 mm/s and using penetration work as a parameter gave the best results to clearly indicate the changes in textural properties of iced shrimp with a high correlation coefficient during storage time (R² = 0.83), while other test methods failed to provide an indication of deterioration.     

Variation in the Fatty Acid Composition Between and Within Two Mantis Shrimp Species,Harpiosquilla harpax and Miyakea nepa: Impact of Season and Sex

ABSTRACT

Harpiosquilla harpax and Miyakea nepa are two out of 400 marine crustaceans commonly known as mantis shrimp. Mantis shrimp are commercially valuable and can be found in fish markets of some Mediterranean and many Asian countries. This study focused on a comparative analysis of variation throughout the year in regards to proximate and total fatty acid composition in the muscle of male and female H. harpax and M. nepa. The most abundant fatty acids identified in the muscle of both species were C16:0, C18:0, docosahexaenoic acid (DHA; C22:6n-3), eicosapentaenoic acid (EPA; C20:5n-3), and C20:4n-6. Results of this study revealed that the muscle fatty acid profiles of H. harpax and M. nepa were not significantly different (p > 0.05), except for C14:0, C16:0, C22:0, and DHA amounts, and were mostly influenced by sex within each sampling month. Generally, the muscle of H. harpax contained higher (p < 0.05) levels of DHA than the muscle of M. nepa. The male mantis shrimp, within each species and most of the sampling months, appeared to have higher (p < 0.05) DHA, total n-3 polyunsaturated fatty acid (PUFA), and PUFA/saturated fatty acid ratio compared to the females. Both species could be considered as a good source of n-3 PUFA in the human diet.     

Quality Attributes and Shelf Life Modeling of Pacific White Shrimp (Litopenaeus vannamei) Stored at Different Temperatures

ABSTRACT

To study and predict quality changes of Pacific white shrimp (Litopenaeus vannamei) during storage at different temperatures (273, 276, 279, 282, and 285 K), changes in quality of sensory assessment (SA), total aerobic counts (TAC), total volatile basic nitrogen (TVB-N), and K-value were determined. An Arrhenius model and a radial basis function neural network (RBFNN) model were built to predict quality changes of Pacific white shrimp, and the relative performances between the two models were compared. For the Arrhenius model, SA and K-values showed good performance in first-order reactions, while TAC and TVB-N showed good performance in zero-order reactions. The relative errors of the RBFNN model for all indicators were within 10%, but the range of relative errors based on the indicators of SA, TAC, TVB-N, and K-value were 1.68–81.20%, 5.54–25.50%, 2.58–71.06%, and 3.66–48.39%, respectively, for the Arrhenius model. Thus, the RBFNN model was more effective for predicting quality changes of Pacific white shrimp during storage between 273 and 285 K.