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1.
Six mixed‐breed dogs were trained to detect 2‐methylisoborneol and geosmin in laboratory‐prepared water. The three dogs most responsive to training were selected for further testing to measure their ability to detect these compounds at levels typical of the early stages of an ‘off‐flavour’ event in catfish pond culture. The dogs were given one out of five choices of off‐flavour and ‘on‐flavour’ water samples and were trained to sit at boxes containing off‐flavour sample tubes. At the lowest concentration tested, 10 ng L?1 of the target compound, the mean correct responses for the three dogs were 37%, 43% and 67%. Additional testing was conducted using off‐flavour pond water samples containing known amounts of these two compounds that occurred naturally. Correct responses for off‐flavour samples varied from 30% to 95%, depending on the sample and the dog. On‐flavour samples were correctly identified with 96% accuracy for all dogs and all samples. Dogs may provide practical early detection of off‐flavour problems in catfish ponds.  相似文献   

2.
Silver carp Hypophthalmichthys molitrix (Valenciennes) were co‐cultured with channel catfish Ictalurus punctatus (Rafinesque) in 0.4 ha earthen ponds to determine the impacts of carp grazing on pond phytoplankton communities and cyanobacterial off‐flavours in catfish. Carp were stocked at densities of 0, 75, or 250 fish ha?1 in seven replicate ponds per treatment. The mean chlorophyll a concentrations (a measure of phytoplankton standing crop) steadily increased in all treatments from about 100 μg L?1 in April to more than 400 μg L?1 by mid‐October. Silver carp had no affect (P>0.1) on chlorophyll a concentrations across all sampling dates (April though October) or for sampling dates late in the growing season (August–October) when the prevalence of cyanobacterial off‐flavours among catfish populations is usually greatest. Silver carp did not eliminate odour‐producing cyanobacteria from pond phytoplankton communities: on sampling dates in September and October, three to six ponds in all treatments contained populations of the odour‐producing cyanobacteria Oscillatoria perornata, Anabaena spp., or both. Failure of silver carp to eliminate odour‐producing cyanobacteria resulted in a relatively high incidence in all treatments of ponds with off‐flavoured catfish. On sampling dates in September and October, catfish in three to five ponds in each treatment were tainted with either musty (2‐methylisoborneol) or earthy (geosmin) off‐flavours. The presence of silver carp had no obvious effect on off‐flavour intensity: on each sampling date, at least three ponds in each treatment contained catfish described as distinctly to extremely off‐flavored. Apparently, hypertrophic conditions in catfish ponds overwhelm the effect of silver carp grazing at the low carp densities used in this study.  相似文献   

3.
Recirculating aquaculture system (RAS) is an increasingly popular alternative to open aquaculture production systems. However, off‐flavours and odours can accumulate in the fish flesh from the circulating water and decrease the fish meat quality. Off‐flavours are typically caused by geosmin (GSM) and 2‐methylisoborneol (MIB) that are lipophilic compounds formed as secondary by‐products of bacterial metabolism. Even though GSM and MIB are not toxic, they often are disliked by consumers, and both have very low human sensory detection limits. Multiple methods have been suggested to remove or decrease GSM and MIB in fish, including ozonation, advanced oxidation processes (AOP)s and adsorption removal from water using activated carbon and/or zeolites. So far, purging with fresh water is the only efficient method available to remove the off‐flavours. There are multiple analytical methods available for the extraction and separation of GSM and MIB from fish flesh and water. This review discusses the current knowledge of GSM and MIB formation, the challenges faced by RAS farms due to these compounds and process solutions available for their removal.  相似文献   

4.
The effect of initial channel catfish (Ictalurus punctatus, Rafinesque, 1818) fingerling biomass (1.4, 1.8, or 2.3 kg m?3) on phytoplankton communities, common off‐flavours and stocker catfish production parameters was evaluated in biofloc technology production tanks. Stocker catfish size (145.5–172.6 g fish?1) at harvest did not differ among treatments, but net yield increased linearly as initial biomass increased (R2 = 0.633). Mean total feed consumption increased linearly with initial catfish biomass (R2 = 0.656) and ranged from 10.7 to 15.8 kg m?3. Total suspended solids (TSS) in all treatments increased linearly with total feed addition, and high TSS appeared to impact negatively daily feed consumption. Initial phytoplankton populations were dominated by small colonial green algae and diatoms, and later transitioned to populations dominated by a small, filamentous cyanobacteria and diatoms. Low, variable concentrations of 2‐methylisoborneol and geosmin were present in biofloc tank water during most of the study and two tanks yielded catfish with 2‐methylisoborneol or geosmin concentrations that might be classified as off‐flavour. One isolate of actinomycete was isolated sporadically from some biofloc tanks, but its abundance was not correlated with 2‐methylisoborneol concentration in tank waters. The microbial sources of 2‐methylisoborneol and geosmin in biofloc tanks remain unidentified.  相似文献   

5.
A headspace solid-phase micro-extraction (SPME) coupled with GS-MS method was used to measure volatile compounds in fillets from musty off-flavor, muddy off-flavor, and on-flavor channel catfish (Ictalurus punctatus), along with water and soil samples from the farm ponds in which the fish had been raised. Two ponds of each type of flavor were selected, and five fish, water, and soil samples were collected from each pond. Linear and multiple linear regression analyses were carried out between/among off-flavor strength and volatile compound contents to investigate their possible correlations. The combination of two strong off-flavor compounds, 2-methylisoborneol (MIB) and geosmin (GSM), was probably mainly responsible for the musty off-flavor in the catfish fillets, and an odorous alcohol, 1-hexanol, was correlated with muddy off-flavor (p =?0.015). There was a strong correlation between beta-cyclocitral and MIB in a pond that gave musty off-flavor catfish contents (p =?0.006), suggesting that these compounds might be generated by similar cyanobacteria. The contents of GSM, MIB, and beta-cyclocitral were high in the water of ponds that yielded off-flavor fish, indicating that catfish might acquire these compounds from pond water.  相似文献   

6.
Aquatic animals raised in recirculating aquaculture systems (RAS) can develop preharvest “off-flavors” such as “earthy” or “musty” which are caused by the bioaccumulation of the odorous compounds geosmin or 2-methylisoborneol (MIB), respectively, in their flesh. Tainted aquatic products cause large economic losses to producers due to the inability to market them. Certain species of actinomycetes, a group of filamentous bacteria, have been attributed as the main sources of geosmin and MIB in RAS. Previous studies have demonstrated that certain nutritional factors can stimulate or inhibit bacterial biomass and geosmin production by certain actinomycetes. In the current study, the effects of two nitrate-nitrogen (NO3--N) levels (20–40 mg/L and 80–100 mg/L) on geosmin and MIB levels in culture water and the flesh of rainbow trout (Oncorhynchus mykiss) raised in RAS were monitored. Water and fish tissue samples were collected over an approximately nine-week period from six RAS, three replicates each of low and high NO3--N, and analyzed for geosmin concentrations using solid phase microextraction–gas chromatography–mass spectrometry. Results indicated no significant difference in geosmin concentrations in water or fish flesh between the low and high NO3--N RAS. Therefore, higher NO3--N levels that may occur in RAS will not adversely or beneficially impact geosmin-related off-flavor problems.  相似文献   

7.
Individuals responsible for tasting catfish in quality control settings sometimes report sensations of sensory adaptation, sensory fatigue and flavor carry-over between samples containing earthy/muddy off-flavors due to geosmin and/or 2-methylisoborneol (MIB). If these experiences are real, sensory evaluation of flavor quality may not be as straightforward as many fish processors and researchers would wish. To determine the influence of these compounds on the sensory evaluation of fish, a series of controlled experiments was conducted. These studies indicate that trained panelists were unable to recognize and evaluate, with precision, the intensity of off-flavor compounds such as geosmin and MIB. However, panelists were precise in evaluating other natural off-flavors, such as fishy. In evaluating two MIB samples in succession, the second sample was perceived as having a lower MIB intensity. The addition of off-flavor compounds to catfish caused the panelists to perceive the desirable flavor chickeny to be lower in intensity, indicating masking. Based on these experiments, a simplified off-flavor quality rating system, consistent with available data, is proposed.  相似文献   

8.
Abstract

In this study, the masking or reduction of off-flavor in tilapia due to various preservation methods such as salting, drying, frying, smoking, microwave heating, marinating and fermentation with carbohydrate mixture (som fak preparation) was investigated by subjecting the processed tilapia to sensory evaluation and analyzing the concentrations of geosmin (1,10-trans -dimethyl-trans -9-decaol) in the processed samples. Dry salting or brining muddy-flavored fish and then drying either by hot air at 50°C or sun-drying resulted to only a slight reduction in the geosmin content of the product. Deep-frying reduced the muddy flavor intensity and geosmin content in salted-dried tilapia. Pretreatment of tilapia fillets with acidified brine before smoking reduced geosmin content and masked the muddy flavor in the smoked product. Microwave cooking of fresh muddy-flavored tilapia showed no effect on its geosmin content nor its off-flavor. Marinating tilapia in acetic acid solution resulted in decreased muddy flavor, and longer marinating period led to lower geosmin content in the product. The geosmin content of som fak made from muddy-flavor and non-muddy-flavor tilapia differed significantly, although sensory evaluation yielded no significant differences between the two types of som fak, and the taste panelists preferred the product fermented for 3 days.  相似文献   

9.
The performance of silver perch fed a commercially available diet based on meat meal (38%), grain legumes (18%), oilseeds (10%), wheat millrun (20%), fishmeal (5%) and fish oil (3%) was compared with experimental diets based on alternative protein sources in two experiments. In Experiment 1, two experimental diets contained similar contents of fishmeal and fish oil as the commercially available reference diet, but soybean (25%) and wheat millrun (>31%) were used to reduce animal protein meals by approximately 50%. The digestible protein and digestible energy of the two experimental diets was either slightly lower (31.5% and 12.8 MJ kg?1) or slightly higher (34.9% and 14.3 MJ kg?1) than the reference diet (32.1% and 13.2 MJ kg?1). In Experiment 2, the two experimental diets contained no fishmeal but included higher amounts of rendered animal meals (41–48%). One of the diets had similar digestible protein to the reference diet (32%) while the other had only 25% digestible protein. Silver perch (38 g for Experiment 1 and 59 g for Experiment 2) were stocked into each of nine 0.1 ha earthen ponds with fish in three ponds fed each diet for 191 days (Experiment 1) or 187 days (Experiment 2). Survival was >94% in all ponds in both experiments. In Experiment 1, growth rates and feed conversion ratios (FCRs) ranged from 2.1 to 2.4 g fish?1 day?1 and 1.7 to 1.9 respectively. Growth rates were significantly (P<0.05) lower for fish fed the experimental diet with the lowest digestible energy content. Growth rates for fish fed the other experimental diet and the reference diet were similar (P>0.05). In Experiment 2, growth rates and FCRs ranged from 2.3 to 2.4 g fish?1 day?1 and 1.6 to 1.7. There were no significant differences in fish performance indices for any of the three diets although experimental power was low (power=0.31). A blind consumer sensory evaluation (taste panel) of fish fed the three diets in Experiment 2 rated fish as ‘highly acceptable’. The diet with the lowest digestible protein content produced the best fish in terms of ‘smell liking’, ‘flavour liking’, ‘muddy flavour strength’ and ‘fresh flavour strength’. These results confirm that soybean meal and/or rendered animal protein ingredients including meat meal and poultry offal meal, and wheat can form the basis for high‐performance, low‐cost diets for intensive pond culture of silver perch.  相似文献   

10.
Abstract

The concentration of geosmin (1,10-trans-dimethyl-trans-9-decaol) in fresh tilapia were analyzed by applying high-vacuum distillation, extraction and gas chromatography techniques. The distribution of geosmin in the fish was determined by examining tissues from various parts of tilapia, along with the rates of geosmin absorption and purging. Analysis showed that when geosmin was added to fish flesh at concentrations ranging from 2.8 to 390 μg per kg of flesh, the rate of recovery was 51 to 89%. Sensory evaluation detected muddy flavor in freshwater tilapia with geosmin content ranging from 7.55 to 9.85 μg/kg of fish flesh. However, panelists failed to detect muddy flavor in brackish water tilapia that contained geosmin only in the range of 1.5 to 2.6 μg/kg. Among various tissues of the fish, the intestines contained the highest geosmin concentration, and appeared in descending order in the abdominal, skin and muscle tissues. After holding for 2 h in water with 5 and 50 μg/l geosmin, tilapia absorbed 17.6 and 42.2 μg/kg geosmin in the flesh, respectively. Holding the fish over longer periods in water with higher geosmin content resulted in a greater amount of absorption. In contrast, transferring muddy-flavored fish to static clean water purged geosmin from the fish but it required at least 16 days to eliminate the muddy flavor.  相似文献   

11.
Channel catfish, Ictalurus punctatus, 88.4 ± 2.6 g/fish, were fed a basal diet amended with 4% of three processed menhaden, Brevoortia tyrannus, oils. These were compared with basal diets amended with 4% corn oil or 4% canola oil. Three replicate aquaria of nine fish each were fed assigned diets twice daily. At 6 wk, fish were group weighed, fillets were collected for sensory evaluation, fatty acid analysis by gas chromatography (GC). In a second study, catfish, 118.8 ± 3.2 g/fish, were stocked into fifteen 0.04‐ha earthen ponds and fed once daily for 16 wk one of four diets containing 2 or 4% of either catfish offal oil or refined (RF) menhaden oil. At harvest, fillets were saved for sensory evaluation and fatty acid analysis. Results showed no significant (P > 0.05) differences among treatments for aquarium study and pond study variables such as weight gain, fillet proximate analysis, or pond production. GC analysis showed that levels of omega‐3 (n‐3) highly unsaturated fatty acids (HUFA) in fillet lipid were significantly (P < 0.05) elevated for fish fed menhaden oil diets. Sensory evaluation revealed that fillets from fish fed RF menhaden oil had satisfactory flavor and could be a source of n‐3 HUFA for humans.  相似文献   

12.
Three isonitrogenous (520 g protein kg?1 DM) and isoenergetic (25 MJ kg?1 DM) diets containing increasing levels of flaxseed oil (FxO; 0%, 40% and 70% of total added oil) at the expense of fish oil (FO) were tested for 33 weeks in groups of 61 individually PIT‐tagged halibut (initial weight, 849 ± 99 g). Effects on fish growth performance, fillet nutritional and sensory quality were determined. Specific growth rate (0.2% day?1), feed conversion ratio (1.2–1.3) and nitrogen and energy retention were not affected by dietary treatments. Dietary fatty acid composition was reflected in fatty acid profiles of halibut muscle, liver and heart. Muscle of fish fed FxO diets contained higher 18:2n‐6 and 18:3n‐3 concentrations whereas 20:5n‐3 and 22:6n‐3 levels were significantly reduced. However, increasing FO replacement induced preferential retention of 22:6n‐3 especially in heart, and a trend for 20:5n‐3 conservation in heart and muscle was observed. FO replacement did not affect colour, texture and the characteristic fish odour and flavour of cooked fillets. By selectively retaining long‐chain polyunsaturated fatty acids halibut can adapt to a lower dietary supply without adverse effects on growth, feed conversion ratio, survival, and fillet nutritional and sensory quality.  相似文献   

13.
Slow growth and losses to bird predation and infectious diseases in winter can compromise the profitability of silver perch farming. To evaluate over‐wintering silver perch (Bidyanus bidyanus) in a recirculating aquaculture system (RAS), fingerlings (38 g) were stocked in either cages in a pond at ambient temperatures (10–21 °C) or tanks in the RAS at elevated temperatures (19–25 °C) and cultured for 125 days. Mean survival (96%), final weight (146 g), specific growth rate (1.07% day?1) and production rate (28.1 kg m?3) of fish in the RAS were significantly higher than for fish over‐wintered in cages (77%, 73 g, 0.53% day?1, 11.1 kg m?3). Fish from both treatments were then reared in cages for a further 129 days. Final mean weight of fish originally over‐wintered in the RAS was 426 g, while fish over‐wintered in cages were only 273 g. To determine optimal stocking densities, fingerlings (11.8 g) were stocked at 500, 1000 or 1500 fish m?3 in tanks in the RAS and cultured for 124 days. Survival was not affected, but growth was significantly slower and feed conversion ratio higher at 1500 fish m?3 compared with 500 or 1000 fish m?3. Results demonstrate that over‐wintering silver perch in an RAS can produce large fingerlings for grow‐out in early spring. This strategy could eliminate bird predation, reduce losses to diseases and shorten the overall culture period.  相似文献   

14.
Abstract.— Many aquaculture studies are conducted in relatively small research ponds and the results are then extrapolated to larger commercial ponds. Implicit in this research is the assumption that there is no relationship between pond size and phytoplankton composition. Study objectives were to assess phytoplankton composition and biomass by several methods in 17 channel catfish Ictalurus punctatus ponds at the Aqua‐culture Research Station, Louisiana Agricultural Experiment Station in Baton Rouge, Louisiana, USA. Pond size ranged from 0.04–0.60 ha. Sampling occurred weekly from 10 September – 1 October 1997. Water temperatures coincided with a transition from summer to fall‐winter conditions. Biomass was assessed by cell counts and quantification of photopigments. Concentrations of dissolved off‐flavor compounds (2‐methylisoborneol and geosmin) were assessed by gas chromatography/mass spectroscopy of water column samples. Cell count data showed differences in dominant species, biovolume, and diagnostic pigment signatures among ponds. The smaller ponds had more diverse phytoplankton composition compared to the larger ponds, whereas chlorophyll levels were nearly an order of magnitude lower in the smaller ponds. Ultraplanktonic (2–20 μm) unicellular cyanobacteria dominated the numerical counts on most sampling dates; however, biovolume transformations of cell count data reduced the dominance of this component relative to cryptophytes, diatoms, and filamentous cyanobacteria. Pigment and microscopic analyses were well correlated. Unialgal isolates of dominant taxa from these samples indicated the presence of at least five genera of off‐flavor producers in these ponds; these taxa included Anabaena, Aphanizomenon, Pseudanabaena, as well as two species of Oscillatoria. Care in extrapolating results from smaller‐sized research ponds to larger commercial ponds is warranted, as is the potential for taxa other than Oscillatoria and Anabaena in forming off‐flavor compounds.  相似文献   

15.
Abstract Producers may capture two to three channel catfish Ictalurus punctatus L. for flavor analysis from ponds scheduled for harvest. If off-flavors are not present in several consecutive fish samples, the population may be considered acceptable for harvest. However, instrumental analysis of the muddy/earthy off-flavor metabolites 2-methylisoborneol (1-R-exo-1,2,7,7-tetramethyl-bicyclo-[2,2,1]-heptan-2-ol) (MIB) and geosmin (lα, 10β-dimethyl-9α-decalol) concentrations in approximately 80 catfish from each of three commercial ponds found both acceptable (on-flavor) and unacceptable (off-flavor) individuals within a single pond (i.e., mixed-flavor populations). Ascertaining the frequency of mixed-flavor populations by instrumentally determining the off-flavor metabolite concentration in muscle tissues from a large number of fish sampled from many ponds at several locations over time is not currently feasible. However, analysis of 12,725 commercial processor flavor assessments collected in 1994 and 1995 indicated 120 instances of individual ponds yielding off-flavor fish followed by on-flavor fish in one day or less. Reports indicate that fish require approximately four days to depurate off-flavors fully, suggesting that a proportion of these rapidly changing flavor assessments may reflect the stochastic selection of fish from mixed-flavor populations rather than a complete and rapid conversion of the flavor quality of entire populations. Factors that contribute to the occurrence of mixed-flavor-populations have not been identified fully. However, increased proportion of fat in catfish fillet tissues has been reported to be correlated with a greater retention of MIB by fish. In this investigation, fish fat contents ranged from 4.45% to 30.45%, and were positively correlated (P < 0.0001) with MIB concentrations. Additionally, the spatial distributions of algal populations within certain commercial catfish ponds were not uniform, and the sensory analysis of the flavor intensity of MIB and geosmin in catfish was more variable than the assessment of the intensity of chickeny and nutty flavors. Probability analysis indicated that in certain mixed-flavor populations there was a 10 to 25% probability of a shipment of fish being rejected due to the random collection of only on-flavor fish prior to harvest followed by the post harvest capture of at least one off-flavor fish. In addition, a chance of no off-flavor fish being sampled from a population containing a proportion of unacceptable fish was indicated. At current sample sizes, replacing sensory analysis with instrumental analysis would not completely avoid problems associated with sampling mixed-flavor-populations. Until effective means to reduce/avoid off-flavor metabolite accumulations in fish are widely available, careful attention to proper sensory evaluation protocols, an enhanced attention to pond conditions that affect flavor quality, the production of leaner more uniform populations of fish, and optimizations of sampling strategies offer the most practical near-term augmentations of current practice.  相似文献   

16.
This study compares sensory attributes, chemical composition, fatty acid profiles, and the taste of raw and cooked red drum Sciaenops ocellatus fillets, reared in seawater (SW) and in freshwater (FW) aquaculture systems. Significant nutritional differences were found in the raw fillets. The total lipid was higher (5.31%) in FW fish than the SW (2.60%). The ratio n‐3/n‐6 and EPA/DHA was higher in SW than FW fillets. The eicosenoic acid was only present in FW fillets. DHA was dominant in SW specimens, contrary to the arachidonic acid level, which was dominant in FW fillets. The assessors perceived a significant difference in the firmness and colour of raw fillets, but its odour intensity was not affected. Fillets from SW fish have higher acceptability (33.3%) than FW fillets (26.4%). Sensory differences in raw fillet were not correlated with consumer perceptions, as cooked fish was considered to have similar flavour, independent of its origin.  相似文献   

17.
Abstract. Samples of water, sediment and fish were collected from six commercial channel catfish, Ictalurus punctalus (Rafinesque), ponds from May to October and analysed for muddy-odour producing compounds. Three episodes of off-flavour in the fish occurred in late summer. The episodes were of 2–3 months' duration and correlated with the levels of 2-methylisoborneol in water, sediment and fish. Oscillatoria agardliii was the dominant phytoplankton in ponds with off-flavour fish. Other known muddy odour-producing compounds such as geosmin, 2-isopropyl-3-mcthoxypyrazinc, 2-isobutyl-3-methoxypyrazine and 2-isobutyl-6-methoxypyrazinc were not detected in the water sediment or at concentrations greater than 5·0 ng/l.  相似文献   

18.
A comparison of composition and sensory evaluation were performed on fillets of Oreochromis niloticus (wild type) and red hybrid tilapia (RHT) (Florida red tilapia ♂× red O. niloticus♀). Fifty male tilapia, 25 O. niloticus (initial weight 159.3 g) and 25 red hybrid (initial weight 132.4 g), were placed in each of three 2.0 m3 volume tanks. The fish were fed a commercial feed containing 35.9% crude protein during the 120‐day experimental period and then killed in cold water (3°C). All the fish were filleted. Twelve fillets from each treatment were used for proximate analyses, five fillets from each treatment were used for fatty acids analyses and the remaining fillets were used for sensory evaluation. The compositional analyses showed similar moisture, true protein and ash content in both genetic groups, but a lower crude fat content was measured in the red hybrid fillets (0.70%) compared with that of O. niloticus fillets (0.97%). No differences between O. niloticus and the red hybrid were observed in their fillet profile of fatty acids. In the sensory evaluation test, a difference in fillet flavour between both genetic groups was perceived. Of the 112 consumers in the preference test, 81.2% perceived a difference in fillet flavour between the two tilapias, with a general preference for the red hybrid over the wild‐type O. niloticus. The benefits of cultivating a RHT with a low lipid content are discussed.  相似文献   

19.
In recent years the freshwater fish market has required more processed goods, as young consumers purchase ready-to-cook food products. In Middle European aquaculture systems carp are the main species. The appearance of new species (African catfish, trout, salmon), as well as the improved import possibilities of value-added fish products have introduced new challenges for fish farmers. In order to maintain the share of carps in fish sales, it is indispensable to develop up-to-date products that meet the needs of present generations. It is necessary to find processing methods that remove the fish bone and the off flavours occurring in Cyprinids. Smoking of carp has a strong tradition in the region, thus there are advantages to the development of smoked carp products, mainly in the form of boned fillets. The present study investigates two smoking methods aimed at ensuring basic information for product innovation. Analyses of the variation of weight, dry matter and lipid content during hot and cold smoking are presented for the case of three species: the common, silver, and grass carp. To determine the most acceptable products, the paper details the results of organoleptic tests, in which five characteristics (appearance, consistence, flavour, smell, and succulence) were investigated. Evaluation results indicate that the hot-smoked carp products are more acceptable, therefore it is hoped that these products, packed in a modified atmosphere, will achieve a strong market share in the near future.  相似文献   

20.
The objective of this study was to demonstrate the feasibility of partial substitution of menhaden fish oil by alternative lipid sources (soybean oil, poultry grease and flaxseed oil) in non‐marine protein‐based shrimp production diet, its influence on fatty acid profile and its final product flavour. Results for the pond study (17 weeks) showed no differences (P ≥ 0.05) in shrimp production among different test diets. Production ranged from 5070 to 5363 kg ha?1; mean final weight, 18.0 to 21.6 g; weekly growth, 1.04 to 1.25 g; survival, 65.6 to 75.4%; and FCR, 1.37 to 1.45. Results from the tank trial (12 weeks) confirmed these findings, final weight, 13.8–14.8 g; weekly growth, 1.1–1.2 g; survival, 92.5–98.3%; FCR, 1.05–1.11; and final standing crop, 4738–5024 kg ha?1. The fatty acids profiles of edible tail muscle reared on the various diets displayed a similar fatty acid profile to that of the diets. The sensory test showed no statistical differences in texture, appearance, aroma and flavour between the shrimp fed diets containing menhaden fish oil and soybean oil. These studies demonstrated that practical shrimp feeds containing non‐marine protein ingredients and a percentage of fish oil replaced by alternative lipid sources had no negative impact on mean final weight, weekly growth, survival, FCR, final standing crop, fatty acids profile and organoleptic properties of Litopenaeus vannamei.  相似文献   

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