Growth Of Pacific White Shrimp Research Articles

Carbohydrate structural complexity modulates the formation, composition and functionality of microbial flocs and its impact on gut microbiota and growth of Pacific white shrimp

The addition of carbohydrate into the culture water to facilitate the growth of heterotrophic bacteria is a common practice in shrimp grow out culture. The present study aimed to evaluate the effect of carbohydrate structural complexity on the formation, composition and functionality of microbial flocs, and how it impacts the gut microbiome and growth of Pacific white shrimp (Litopenaeus vannamei). Pacific white shrimp juveniles (1.07 ± 0.01 g) were randomly distributed in 12 indoor fiber tanks (50 cm × 50 cm × 100 cm) and maintained for 30 days at stocking density 107 ind.m−3 (20 ind per tank). Three different carbohydrate sources were added according to the treatments, that is dextrose (Dx) representing simple carbohydrate, potato starch (St) representing starch polysaccharide, and cellulose (Cl) representing complex non-starch polysaccharide. Settleable solids level and particle size of microbial flocs in Dx treatment were consistently higher than those of St and Cl treatments (P < 0.05). Amino acids concentrations were not significantly different amongst the treatments (P > 0.05), however essential amino acid index relative to shrimp requirement was the lowest in the Dx treatment (P < 0.05). Shannon diversity index level in the microbial flocs with Cl as the carbohydrate sources was higher compared to Dx and St. T6SS2 and ExsA gene expressions in the co-culture of Vibrio parahaemolyticus and the microbial floc suspension was highly upregulated in Dx treatment. Accordingly, differences in the shrimp gut microbiome was also observed amongst the treatments. The highest growth performance was demonstrated by the shrimp cultured with cellulose as the carbohydrate source. In conclusion, carbohydrate structural complexity could significantly affect the characteristics of microbial flocs suspended in the culture water and could ultimately affect the shrimp growth performance.

Modeling the growth of Pacific white shrimp (Litopenaeus vannamei) using the new Bayesian hierarchical approach based on correcting bias caused by incomplete or limited data

The revenue, costs, and profit of an aquaculture farm are based on the weight of animal protein sold. Thus, there is a relationship between the economic and zootechnical indexes to the growth model of animals in a production system. The growth modeling of cultivated organisms can be used as a production management tool, allowing estimates of anticipated size at harvest, waste outputs, as well as nutrient and feed requirements, helping in decision-making in the face of Aquaculture 4.0. It is important to emphasize that recent research has indicated the possible underestimation of parameters in nonlinear growth models due to the characteristic of incomplete or limited data in aquaculture. Therefore, the objective of this research was to model the growth of Pacific white shrimp (Litopenaeus vannamei) in an industrial-scale shrimp farm in northeastern Brazil. Based on the Bayesian methodology for correcting this bias, six nonlinear hierarchical growth models were evaluated in this research (Morgan-Mercer-Flodin, Michaelis–Menten, Weibull, von Bertalanffy, Gompertz, and logistic growth equation) and fitted to real data from a shrimp farm in northeastern Brazil. The model was validated based on the predictive capacity (accuracy) to forecasting shrimp growth at different hierarchical levels. Finally, for one of the main expected results, a sensitivity analysis was performed to compare different treatments according to the new approach. The Weibull growth equation stands out as the best among all those studied (WAIC = 2661.3, LOO-IC = 2705.2). Although it presented a poor fit for the hierarchical population level, good predictions were realized at the pond level and at the production cycle level. The dataset was split into fit and homologation subsets for a model validation analysis which showed an accuracy of 95.76% and 85.71% at the pond and production cycle levels respectively. The proposed method detected subtle differences between production cycles, which would be imperceptible if analyzed using the zootechnical indices usually practiced in shrimp farms. The new approach can contribute to improving products, processes, and decision-making in aquaculture management.

Vibriocidal Activity of Ethanol Extract of Moringa Leaves and Its Effect on the Growth of Pacific White Shrimp

This study aimed to evaluate the vibriocidal potency of Moringa leaf ethanol extract (MLEE) and assess the effectiveness of dietary supplementation of MLEE on Pacific white shrimp growth performance. A vibriocidal activity was performed using disk diffusion and tube dilution methods. The results showed Vibrio parahaemolyticus was more susceptible than Vibrio harveyii with an inhibitory zone of 11.30 to 22.90 mm. The minimum inhibitory concentration (MIC) of MLEE against V. parahaemolyticus was recorded at 12.5%, similar to V. harveyii. The effectiveness of MLEE on diet was monitored by the growth of the shrimps for 40 days of culture. Shrimps with an average initial weight of 2.50±0.05 g were acclimatized in 10 days. The MLEE was administered to the shrimps at different concentrations i.e., 10%, 15%, 20%, and 25%. The control diet was prepared without MLEE supplementation. After 40 days of culture, the shrimps fed with 10% of MLEE had the best growth. This study reported that MLEE potentially become vibriocidal agents. However, the administration on shrimp had no beneficial effect on its growth performance.

Efficacy of freeze-chilled storage combined with tea polyphenol for controlling melanosis, quality deterioration, and spoilage bacterial growth of Pacific white shrimp (Litopenaeus vannamei)

This study aimed to investigate melanosis, quality attributes, and bacterial growth of freeze-chilled Pacific white shrimp (Litopenaeus vannamei) during 6 days of chilled storage, as well as the preservative effects of tea polyphenol on shrimp. The results showed that freeze-chilled storage retarded the growth of bacteria and the accumulation of putrescine in shrimp. The growth of spoilage bacteria Photobacterium and Shewanella were inhibited. However, freeze-chilled storage aggravated melanosis and lipid oxidation. The total volatile basic nitrogen (TVB-N) slightly accumulated in the thawed shrimp. The incorporation of tea polyphenol preserved freeze-chilled shrimp. Melanosis and lipid oxidation of shrimp were alleviated. The accumulation of biogenic amines, TVB-N, hypoxanthine riboside, and hypoxanthine were retarded. Meanwhile, the growth of spoilage bacteria Pseudoalteromonas, Photobacterium, Psychrobacter, and Carnobacterium were inhibited. Based on sensory analysis, the shelf-life of chilled, freeze-chilled, and freeze-chilled tea polyphenol shrimp were 4 days, 3 days, and 6 days, respectively.

Effects of adding rotifers on the water quality, plankton composition and growth of Pacific white shrimp, Litopenaeus vannamei juvenile, when cultured with biofloc technology

The objective of this study was to evaluate the effect of the addition of Brachionus plicatilis to Litopenaeus vannamei in a nursery biofloc technology (BFT). Four treatments were used: BFT (without addition of rotifers); BFT-10 (addition of 10 rotifers mL−1); BFT-20 (addition of 20 rotifers mL−1) and BFT-30 (addition of 30 rotifers mL−1), all in triplicate. The shrimp (3.4 ± 0.02 mg) were reared for 42 days at a density of 3000 shrimp m−3. The rotifers were added every 10 days (from day 1 to 30). The final weight (1.26 g) and yield (3.42 kg m−3) were significantly higher at BFT-30 than those from BFT. The percentage of sucrose-fermenting gram-negative bacteria increased and non-sucrose-fermenting gram-negative decreased by the end of the period. The crude protein of bioflocs was significantly higher at BFT-30 than those from BFT-10 or BFT treatments, while crude lipid of bioflocs was significantly higher at BFT-20 and BFT-30 than the BFT. The best shrimp performance was observed in BFT-30 and BFT-20, indicating the benefits of rotifers on enhancing the microbial floc content and growth to L. vannamei in BFT.

Characterization and Expression Analysis of Insulin Growth Factor Binding Proteins (IGFBPs) in Pacific White Shrimp Litopenaeus vannamei.

The insulin signaling (IIS) pathway plays an important role in the metabolism, growth, development, reproduction, and longevity of an organism. As a key member of the IIS pathway, insulin-like growth factor binding proteins (IGFBPs) are widely distributed a family in invertebrates and vertebrates that are critical in various aspects of physiology. As an important mariculture species, the growth of Pacific white shrimp, Litopenaeus vannamei, is one of the most concerning characteristics in this area of study. In this study, we identified three IGFBP genes in the genome of L. vannamei and analyzed their gene structures, phylogenetics, and expression profiles. LvIGFBP1 was found to contain three domains (the insulin growth factor binding (IB) domain, the Kazal-type serine proteinase inhibitor (Kazal) domain, and the immunoglobulin C-2 (IGc2) domain), while LvIGFBP2 and LvIGFBP3 only contained a single IB domain. LvIGFBP1 exhibited high expression in most tissues and different developmental stages, while LvIGFBP2 and LvIGFBP3 were only slightly expressed in hemocytes. The RNA interference of LvIGFBP1 resulted in a significantly smaller increment of body weight than that of control groups. These results will improve our understanding of the conservative structure and function of IGFBPs and show potential applications for the growth of shrimp.

The effects of magnesium concentration in low‐salinity water on growth of Pacific white shrimp ( Litopenaeus vannamei )

The current study evaluates the effect of different Mg levels in low-salinity (3 g/L) water on growth, survival, haemolymph osmolality, cationic composition in haemolymph, carapace and whole body of Pacific white shrimp, Litopenaeus vannamei. A low-cost salt mixture (LCSM) comprised of Na, K, Ca and Mg concentrations of 298, 9, 17 and 39 mg/L, respectively, in a 1-g/L solution was modified by decreasing the Mg level of LCSM to allow different Mg levels in the culture medium (100, 78, 55, 30, 17, 13 and 12 mg/L). Reconstituted sea salt (RSS) was used as the control treatment with Mg level of 129 mg/L. A 42-day growth trial (initial weight: 0.11 ± 0.01 g and stocking density: 20 shrimp/tank) was carried out in 150-L plastic tanks, each equipped with a fluidized bed biofilter. As Mg2+ level was reduced, there was a subsequent reduction (p < 0.05) in shrimp performance reflected in final weight, weight gain, haemolymph osmolality, osmoregulatory capacity, Mg2+ concentration in haemolymph, carapace and whole body of shrimp paralleled by an increase in feed conversion ratio (FCR). Low haemolymph osmolality and Mg2+ concentrations (p < 0.05) in shrimp haemolymph were found to be indicative of stress, which was ultimately reflected as reduced growth and increased FCR in low Mg2+ concentrations at 3 g/L salinity.

The effects of feed leaching on the growth of Pacific white shrimp Litopenaeus vannamei in a green‐water tank system

The authors have no conflict of interest to declare. The data that support the findings of this study are available from the corresponding author upon reasonable request.

A novel micro‐organism for removing excess ammonia‐N in seawater ponds and the effect of Cobetia amphilecti on the growth and immune parameters of Litopenaeus vannamei

To investigate the feasibility of using micro‐organisms for ammonia‐N removal, six strains were isolated from Chinese white shrimp, Fenneropenaeus chinensis, seawater culture ponds in Dongying (Shandong, China). Of these, strain DY‐01, which exhibited the highest capacity to degrade ammonia‐N, removed 61.7% of the total ammonia‐N (50 mg/L) in 8 hr. An investigation of the factors affecting the removal efficiency indicated the optimum conditions to be 30°C, pH 8.0, and a salinity level of 30 g/L; 16S rDNA gene sequencing and biochemical analysis identified strain DY‐01 as Cobetia amphilecti, which has not previously been reported to degrade ammonia‐N. This strain also boosted the growth of Pacific white shrimp, Litopenaeus vannamei (p &lt; .05), at a concentration of 107 CFU/mL, with no harmful effects on the shrimp's immune system. This study has thus identified a novel aerobic nitrifying bacterium that is potentially an excellent candidate for improving the water quality in mariculture ponds.

Growth of Pacific White Shrimp Fed Diets Containing a Mixture of Soybean Meal and Tuna Silage

AbstractThis study evaluated the use of tuna by‐product silage (TBS) in diets based on soybean meal (SBM) for the Pacific white shrimp Litopenaeus vannamei. A diet based on fish meal (FM, positive control) only was compared with five isonitrogenous formulations (35% crude protein) based on SBM containing increasing dietary levels of TBS (0, 14.9, 29.8, 44.7, or 59.6%) replacing 0% (TBS0, negative control), 25% (TBS25), 50% (TBS50), 75% (TBS75), or 100% (TBS100), respectively, of the protein derived from SBM. A diet containing tuna by‐product meal (TBM) as the sole protein source and one using a commercial feed as reference were also included. Each diet was tested on shrimp in triplicate over 41 d using 70‐L fiberglass tanks in a closed recirculating system. Each tank was stocked with 10 juvenile shrimp (mean initial weight, 1.09 g). Shrimp fed diet TBS25 grew as well as those fed diets with 100% of the protein from FM. The growth differences were mainly attributable to differences in the nutritional quality of diets. Whole‐body composition was significantly affected by diet. The broken‐line regression model using thermal growth coefficient data allowed us estimate that the maximum inclusion level of TBS in shrimp fed the SBM‐based diet was 26.31%. To reduce the cost of shrimp feed, the ratio of 75% SBM and 25% TBS proteins seems to be the best formulation for juvenile Pacific white shrimp diets.

Assessment of the relative contribution of dietary nitrogen from fish meal and biofloc meal to the growth of Pacific white shrimp (Litopenaeus vannamei )

The relative contribution of the dietary nitrogen supplied by fish meal and a biofloc meal to the growth of Pacific white shrimp was evaluated using stable isotope analysis. Biofloculated material was obtained from an experimental tilapia culture system. Five formulated diets were supplied. Two of them consisted in isotopic controls having only fish meal or biofloc meal as protein source. Three mixed diets were formulated with varying proportions of these ingredients on a dietary nitrogen basis (75:25, 50:50 and 25:75). At the end of the trial, survival rates were similar (92–100%) but significant differences in mean final weight were observed and a negative correlation between the inclusion of biofloc meal and weight gain was evidenced. Mean final weight in shrimp fed on diet containing only fish meal was 2.8 g, while mean final weight of animals fed on diet containing 50% biofloc was 1.9 g. Isotopic mixing models indicated that all diets contributed higher proportions of dietary nitrogen from fish meal than from biofloc meal. Dietary nitrogen available in diets containing 25%, 50% and 75% of biofloc meal was incorporated in muscle tissue as 5%, 41% and 64% respectively. Diet supplying 25% of nitrogen from biofloc was the only mixed diet eliciting growth comparable to diet containing only fish meal. Lower growth and nitrogen deposition in shrimp fed on diets containing high proportions of biofloc meal were possibly associated to the use of only two protein sources and a restriction of essential amino acids.

Impact of Solar UV-B Radiation in the Culture of Pacific White Shrimp, Litopenaeus vannamei, Saudi Arabia

Middle East and North African (MENA) region are known for high levels of solar UV radiation. A study was conducted to assess the effect of UV radiation on phytoplankton chlorophyll, β-carotene and growth of pacific white shrimp, Litopenaeus vannamei in HDPE liner culture ponds for 98 days. The experiment is based on control ponds (direct sunlight) and treatment ponds (Green house) using intensive shrimp culture method. Shrimp juveniles (SPF) at the rate of 100/m2 were stocked in each pond and fed with a standard fishmeal based supplementary pellet feed having 35% protein in diet. Physico-chemical parameters of pond water, UV-B radiation, Chlorophyll-a, shrimp growth and β-carotene in meat were monitored during the study period. Significant reduction (p&lt;0.01) in UV-B radiation was found in treatment ponds in comparison with control ponds at an average reduction of 23.2% for surface water due to filtration. Chlorophyll-a in phytoplankton and β- carotene in shrimp were found to be increased in treatment ponds due to low UV-B radiation. However, shrimp growth was not affected significantly (P&gt;0.01) by UV-B radiation in culture ponds.

Replacement of fish meal by protein soybean concentrate in practical diets for Pacific white shrimp

The objective of this work was to evaluate the performance of Litopenaeus vannameifed different levels (0, 25, 50, 75, and 100%) of soybean protein concentrate (63.07% crude protein, CP) to replace fish meal-by product (61.24% CP). The study was conducted in clear water in fifteen 800 L tanks equipped with aeration systems, constant heating (29 oC), and daily water exchange (30%). Each tank was stocked with 37.5 shrimp/m3 (3.03±0.14 g). Feed was supplied four times a day, at 6% of the initial biomass, adjusted daily. After 42 days, the weight gain of shrimp fed diets with 0 and 25% protein replacement was higher than that observed in shrimp fed 100% replacement, and there were no differences among those fed the other diets. Feed efficiency and survival did not differ among shrimp fed different protein replacements. There was a negative linear trend for growth parameters and feed intake as protein replacement with soybean protein concentrate increased. Fish meal by-product can be replaced by up to 75% of soybean protein concentrate, with no harm to the growth of Pacific white shrimp.

Effect of dietary formic acid and astaxanthin on the survival and growth of Pacific white shrimp (Litopenaeus vannamei) and their resistance to Vibrio parahaemolyticus.

A 90-day feeding trial was conducted to evaluate the effects of formic acid (FA) and astaxanthin (AX) on growth, survival, immune parameters, and tolerance to Vibrio infection in Pacific white shrimp. The study was divided into two experiments. In experiment 1, postlarvae-12 were randomly distributed into six groups and then fed four times daily with six experimental diets contained 0.3 % FA, 0.6 % FA, 50 ppm AX, 0.3 % FA + 50 ppm AX, 0.6 % FA + 50 ppm AX, or none of these supplements (control diet). After 60 days of the feeding trials, the body weight of all treatment groups was not significantly different from the control group, although shrimp fed formic acid had significantly lower body weight than shrimp fed 50 ppm AX. However, the 0.6 % FA + 50 ppm AX group had a significantly higher survival rate (82.33 ± 8.32 %) than the control group (64.33 ± 10.12 %). In experiment 2, Vibrio parahaemolyticus was added to each tank to obtain a final concentration of 104 colony-forming units/mL. Each treatment group received the aforementioned diets for another 30 days. At the end of this experiment, there was no difference in the weight gain among all experimental groups. However, the survival rate of shrimps whose diet included FA, AX, and their combination (in the range of 45.83–67.50 %) was significantly higher than the control group (20.00 ± 17.32 %). FA-fed shrimps also had significantly lower total intestinal bacteria and Vibrio spp. counts, while immune parameters [total hemocyte count (THC), phagocytosis activity, phenoloxidase (PO) activity, and superoxide dismutase (SOD) activity] of AX-fed groups were significantly improved compared with the other groups. In conclusion, FA, AX, and their combination are useful in shrimp aquaculture.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-1234-x) contains supplementary material, which is available to authorized users.

Isotopic Evaluation of the Nutritional Contribution of Poultry By‐product Meal and Fish Meal to the Growth of Pacific White Shrimp, Litopenaeus vannamei

AbstractThe nutritional contribution of the dietary nitrogen supplied by poultry by‐product meal (PBM) and fish meal (FM) to the somatic growth of Pacific white shrimp, Litopenaeus vannamei, was assessed by means of stable isotope analysis. Seven experimental diets were formulated with different proportions of PBM replacing FM. Practical diets were formulated to replace 0, 35, 50, 65, 80, 95, and 100% of FM with PBM, on a dietary nitrogen basis. At the end of the experiment, there were no significant differences in survival among dietary treatments (89 ± 5%); however, significant differences in final wet weights were observed. Diets having FM replacement levels of 35 and 50% with PBM promoted mean final weights (708–789 mg) similar to those observed in shrimps fed on diet containing 100% FM (874 mg). Shrimp final mean weight significantly decreased as a function of PBM inclusion (r = −0.98) owing to the use of only two dietary nitrogen sources and by possible nutritional restrictions as PBM levels increased. The relative proportions of dietary nitrogen supplied by PBM and FM were incorporated in muscle tissue at proportions that were statistically similar to those established in the dietary formulations.

Oral application of probiotic, prebiotic, and synbiotic in Pacific white shrimp(Litopenaeus vannamei)challenged with Vibrio harveyi

&lt;p&gt;The use of antibiotics for controlling of luminous vibriosis caused by &lt;em&gt;Vibrio harveyi&lt;/em&gt; is restricted now, because it induces antibiotic-resistant bacteria and leave residue in shrimp’s body. An alternative solution that can be done to treat the disease is by using applications of probiotic, prebiotic, and synbiotic. The aim of this research was to examine the effect of probiotic, prebiotic, and synbiotic on the survival rate and growth of Pacific white shrimp against &lt;em&gt;V. harveyi&lt;/em&gt; infection. Feed as a treatment was supplemented with probiotic 1%, prebiotic 2%, and probiotic 1%+prebiotic 2% (synbiotic). Shrimps feed without supplementation of probiotic and prebiotic was used as a control treatment. The shrimps were maintainedin the aquarium (60×30×35 cm&lt;sup&gt;3&lt;/sup&gt;) with a density of 40 shrimps/40 L and an average weight of 0.4±0.1 g. After 30 days of feeding treatment, the shrimp was challenged by immersion method with &lt;em&gt;V. harveyi&lt;/em&gt; solution containing 10&lt;sup&gt;6&lt;/sup&gt; CFU/mL. The results showed that before challenge, synbiotic feed treated shrimp has a growth rate (5.89%), feed conversionrate (1.21), and a high survival rate (80%). After challenge, survival rate (83.33%) of shrimp fed diet supplemented with synbiotic was higher than prebiotic (51.67%) and positive control (31.67%).&lt;/p&gt; &lt;p&gt;Keywords: probiotic, prebiotic, synbiotic, &lt;em&gt;Vibrio harveyi&lt;/em&gt;,Pacific white shrimp&lt;/p&gt;

Selection for growth performance of tank-reared Pacific white shrimp, Litopenaeus vannamei

Seven growth-related traits were measured to assess the selection response and genetic parameters of the growth of Pacific white shrimp, Litopenaeus vannamei, which had been domesticated in tanks for more than four generations. Phenotypic and genetic parameters were evaluated and fitted to an animal model. Realized response was measured from the difference between the mean growth rates of selected and control families. Realized heritability was determined from the ratio of the selection responses and selection differentials. The animal model heritability estimate over generations was 0.44±0.09 for body weight (BW), and ranged from 0.21±0.08 to 0.37±0.06 for size traits. Genetic correlations of phenotypic traits were more variable (0.51–0.97), although correlations among various traits were high (>0.83). Across generations, BW and size traits increased, while selection response and heritability gradually decreased. Selection responses were 12.28%-23.35% for harvest weight and 3.58%–13.53% for size traits. Heritability estimates ranged from 0.34±0.09 to 0.48±0.15 for harvest weight and 0.17±0.01–0.38±0.11 for size traits. All phenotypic and genetic parameters differed between various treatments. To conclude, the results demonstrated a potential for mass selection of growth traits in L. vannamei. A breeding scheme could use this information to integrate the effectiveness constituent traits into an index to achieve genetic progress.

Simultaneous estimation of the nutritional contribution of fish meal, soy protein isolate and corn gluten to the growth of Pacific white shrimp (Litopenaeus vannamei) using dual stable isotope analysis

The nutritional contribution of the dietary nitrogen, carbon and total dry matter supplied by fish meal (FM), soy protein isolate (SP) and corn gluten (CG) to the growth of Pacific white shrimp Litopenaeus vannamei was assessed by means of isotopic analyses. As SP and CG are ingredients derived from plants having different photosynthetic pathways which imprint specific carbon isotope values to plant tissues, their isotopic values were contrasting. FM is isotopically different to these plant meals with regards to both, carbon and nitrogen. Such natural isotopic differences were used to design experimental diets having contrasting isotopic signatures. Seven isoproteic (36% crude protein), isoenergetic (4.7kcal g−1) diets were formulated; three diets consisted in isotopic controls manufactured with only one main ingredient supplying dietary nitrogen and carbon: 100% FM (diet 100F), 100% SP (diet 100S) and 100% CG (diet 100G). Four more diets were formulated with varying mixtures of these three ingredients, one included 33% of each ingredient on a dietary nitrogen basis (diet 33FSG) and the other three included a proportion 50:25:25 for each of the three ingredients (diets 50FSG, 50SGF and 50GFS). At the end of the bioassay there were no significant differences in growth rate in shrimps fed on the four mixed diets and diet 100F (k=0.215–0.224). Growth rates were significantly lower (k=0.163–0.201) in shrimps grown on diets containing only plant meals. Carbon and nitrogen stable isotope values (δ13C and δ15N) were measured in experimental diets and shrimp muscle tissue and results were incorporated into a three-source, two-isotope mixing model. The relative contributions of dietary nitrogen, carbon and total dry matter from FM, SP and CG to growth were statistically similar to the proportions established in most of the diets after correcting for the apparent digestibility coefficients of the ingredients. Dietary nitrogen available in diet 33FSG was incorporated in muscle tissue at proportions representing 24, 35 and 41% of the respective ingredients. Diet 50GSF contributed significantly higher amounts of dietary nitrogen from CG than from FM. When the level of dietary nitrogen derived from FM was increased in diet 50FSG, nutrient contributions were more comparable to the available dietary proportions as there was an incorporation of 44, 29 and 27% from FM, SP and CG, respectively. Nutritional contributions from SP were very consistent to the dietary proportions established in the experimental diets.

Use of Fish Hydrolysates and Fish Meal Byproducts of the Alaskan Fishing Industry in Diets for Pacific White Shrimp Litopenaeus vannamei

AbstractWe determined the suitability of four fish hydrolysates and two fish meals (Pacific halibut Hippoglossus stenolepus and arrowtooth flounder Atheresthes stomias; all derived from byproducts of the Alaskan fishing industry) as replacements for menhaden fish meal in shrimp diets. A control diet (30% crude protein; 8.5% crude lipid) was produced with menhaden meal (13% of diet). Experimental diets were manufactured by using each hydrolysate or fish meal to replace 50% of the menhaden meal on an isonitrogenous basis. Each diet was fed to Pacific white shrimp Litopenaeus vannamei in an outdoor, zero‐water‐exchange system for 8 weeks. Final weight, survival, feed efficiency, and growth rate were compared among treatments by analysis of variance. The final weights and growth of Pacific white shrimp fed two of the hydrolysates (one acidified to pH 3.8 and left in a liquid state; the other acidified, then neutralized to pH 6.5 and drum‐dried) and the two fish meals were not different from those of shrimp fed the control diet. Shrimp that were given the other two hydrolysates (one acidified to pH 3.8 and then drum‐dried; the other hydrolyzed [but not acidified] and then drum‐dried) had lower final weights and growth than shrimp fed the control diet. These data indicate that the two fish meals and two of the hydrolysates in this trial can replace 50% of menhaden meal in diets for shrimp, although there is some loss of growth potential in some cases. The lack of a diet effect on feed efficiency indicates that the growth differences were mostly the result of differences in feed intake rather than nutritional quality.

Microbial Community Analysis of Water, Foregut, and Hindgut during Growth of Pacific White Shrimp, Litopenaeus vannamei, in Closed‐System Aquaculture

Abstract In closed recirculating systems, a particulate matter consisting of bacteria, algae, fungi, and detritus develops spontaneously. This microbial floc can serve as a high‐protein food source for finfish and shellfish and has the potential to supplement the protein required in shrimp feed. To advance the use of microbial floc as a feed supplement, it is necessary to manipulate its microbial components, which requires thorough characterization of the bacterial components. Pacific white shrimp, Litopenaeus vannamei, were raised in a closed recirculating system, and water was compared to the contents of shrimp foreguts and hindguts. Water consistently contained less microbial biomass than did shrimp guts, but 16S rDNA sequences indicated that water was more diverse than shrimp guts. Phylogenetic analysis of 16S rDNA sequences retrieved from water and shrimp foregut grouped these sequences into various unrelated generic clusters. Fatty acid analysis demonstrated that shrimp feed was not a major contributor of microbial fatty acids to shrimp tanks, as the feed mostly contained polyunsaturated fatty acids, which are typically found only in eukaryotes. It is hoped that elucidating more details about the various components of microbial floc will help in understanding its development and will lead to its use as a high‐protein feed supplement.