No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Shrimp ( Litopenaeus vannamei ) production and stable isotope dynamics in clear-water recirculating aquaculture systems versus biofloc systems
Abstract
Closed recirculating aquaculture systems (RAS) offer advantages over traditional culture methods including enhanced biosecurity, the possibility of indoor, inland culture of marine species year-round and potential marketing opportunities for fresh, never-frozen seafood. Questions still remain regarding what type of aquaculture system may be best suited for the closed-system culture of marine shrimp. In this study, shrimp (Litopenaeus vannamei) were grown in clear-water RAS and in biofloc-based systems. Comparisons were made between the system types with respect to water quality, shrimp production and stable isotope dynamics used to determine the biofloc contribution to shrimp nutrition. Ammonia and nitrite concentrations were higher, and shrimp survival was lower in the biofloc systems. Although stable isotope levels indicated that biofloc material may have contributed 28% of the carbon and 59% of the nitrogen in shrimp tissues, this did not correspond with improved shrimp production. Overall, the water column microbial communities in biofloc systems may be more difficult to manage than clear-water RAS which have external filters to control water quality. Biofloc does seem to offer some nutritional contributions, but exactly how to take advantage of that and ensure improved production remains unclear.
... One metric to consider with biofloc systems is the nutritional contribution of floc particles. Stable isotope ratios for carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N) can be measured in floc particles, shrimp feed, and shrimp tissues to determine the contribution of biofloc to shrimp nutrition (Ray and Lotz, 2017). Data from isotopic fractionation studies indicate that animals store a greater portion of heavy isotopes in their tissues while preferentially excreting lighter isotopes (Gannes et al., 1997). ...
... Where δ source corresponds to shrimp feed, and δ product is the shrimp (Ray and Lotz, 2017). Although CW shrimp may have consumed other items attached to the sides or bottom of the tanks besides the pelleted feed, it is unlikely they had access to any biofloc particles, which is the subject of interest in this case . ...
... material. If the duration of the project were extended this may enhance microbial N accumulation, possibly improving water quality, and enhancing the nutritional contribution of biofloc to shrimp (Ray and Lotz, 2017;. ...
... Both authors attributed these findings to the ability of tilapia to effectively consume and utilize the additional nutrients provided by biofloc that were unavailable in RAS. On the other hand, despite bioflocs providing nutrition to white shrimp (Litopenaeus vannamei), this did not confer better growth compared to RAS and actually decreased survival (Ray and Lotz, 2017). A somewhat similar finding was recently found with both grey mullet (Mugil cephalus) and tench (Tinca tinca) juveniles in which BFT significantly decreased their survival and growth compared to RAS (Vinatea et al., 2018). ...
... A somewhat similar finding was recently found with both grey mullet (Mugil cephalus) and tench (Tinca tinca) juveniles in which BFT significantly decreased their survival and growth compared to RAS (Vinatea et al., 2018). Ray and Lotz (2017) and Vinatea et al. (2018) suggested these findings was due to consistently higher ammonia-N and/or nitrite-N levels in BFT systems that were better managed with RAS. ...
... It was suggested that because NH 3 was consistently higher in the BFT systems, compared to RAS, this may have induced stress in both species and therefore negatively affected both their survival and growth. Indeed, slightly elevated ammonia-N levels are not uncommon in biofloc-based systems compared to RAS (Green, 2015;Long et al., 2015;Ray and Lotz, 2017), however, other factors were also suggested as potential contributors. In the case of the tench, this species naturally produces a substantial amount of mucous, and without mechanical filtration, this was observed to accumulate in the BFT tanks that began clogging their gills and thus leading to higher mortalities (Vinatea et al., 2018). ...
African catfish (Clarias gariepinus) and lemon fin barb hybrid (LFBH) (Hypsibarbus wetmorei ♂ × Barbodes gonionotus ♀) were cultured in either a biofloc technology (BFT) system or an individual recirculating aquaculture system (RAS) and their survival, growth, feeding efficiencies and biochemical composition were then compared after 8 weeks. LFBH and African catfish were chosen based on their different feeding habits. In the BFT treatments, glycerol was added to create a carbon to nitrogen ratio of 15, while the RAS system consisted of a fine mesh mechanical and biological filter. Each of the four treatments was triplicated, with each replicate consisting of 20 African catfish (0.98 ± 0.05 g) or LFBH (1.77 ± 0.02 g). Water quality and biofloc formation were examined weekly while the biofloc proximate composition was measured in weeks 5 and 8. During weeks 6, 7 and 8 the total viable bacterial colony forming units (CFU) were quantified. Regardless of species, biofloc formation was similar but the crude protein, lipid and ash significantly decreased from week 5 to week 8. However, biofloc crude protein and ash were significantly higher in the LFBH treatment. Total viable CFU were significantly higher (P < 0.05) in BFT compared to RAS, with LFBH having significantly more (P < 0.05) than African catfish. The proximate composition of the fish were unaffected by either system. Implementing BFT significantly (P < 0.05) improved both African catfish and LFBH growth, but this improvement was substantially higher for LFBH (41.6%) than for African catfish (7.6%). This may be due to a better ability of LFBH to consume smaller particles. Preliminary results also indicate that the nutritional composition of bioflocs could be influenced by biofloc age, which could have implications to solids management.
... Removing shrimp shells, dead individuals, and sewage in time are challenging tasks but essential to ensure the success of this particular aquaculture process. In order to prevent shrimp from escaping, the backwater outlet is designed to allow the opening of gaps [18], and anti-escape nets and ...
... Removing shrimp shells, dead individuals, and sewage in time are challenging tasks but essential to ensure the success of this particular aquaculture process. In order to prevent shrimp from escaping, the backwater outlet is designed to allow the opening of gaps [18], and anti-escape nets and similar tools are added [19]. However, these often lead to the clogging of outlets. ...
Designing good recirculating aquaculture systems (RASs) is challenging in shrimp aquaculture. In this study, two sets of RASs were constructed using sea cucumber nursery tanks for rearing Litopenaeus vannamei. Recirculating aquaculture was supported by key technologies such as sewage collection and aeration systems adapted to the rectangular tanks and technologies for the removal of sewage, shrimp shells, and dead individuals. Six-hundred and eighty-five thousand juveniles were selected for rearing in the newly constructed RASs, where the average stocking density was 1013 shrimp/m3. During the recirculating aquaculture period of 53 days, the water temperature of the tanks was 24–31 °C, the salinity was 25–32‰, the pH was 6.4–8.2, the DO was ≥ 4.9 mg/L, the concentration of total ammonia nitrogen (TAN) was maintained between 0.17 and 4.9 mg/L, the concentration of nitrite nitrogen (NO2-N) was between 0.12 and 4.7 mg/L, and the total number of Vibrio bacteria remained between 330 and 9700 cfu/mL. At the end of the experiment, the final average weight of individual shrimp was 13.43 g, and the average yield reached 12.92 kg/m3. The great improvement in growth performance marks a breakthrough in RAS technology of shrimp, and it supports the use of an innovative methodology for the retrofitting and utilization of idle sea cucumber nursery tanks.
... RAS facilitate very low water use rates; however, some water exchange does occur and commercial marine salt mixes are typically used to provide the needed minerals for marine shrimp (Ray & Rode, 2019;Tidwell, 2012). Most indoor RAS use brackish water at a salinity of 10 g L -1 or higher, as shrimp tend to be more susceptible to toxic ammonia, nitrite, and nitrate at lower salinities (Ray & Lotz, 2017). Artificial marine salt water can be used for about three production cycles using the same water before elevated nitrate levels begin to degrade shrimp growth and survival (Furtado et al., 2015;Kuhn et al., 2010). ...
... Although the 100 treatment had significantly higher NO 2 -N levels over the 25 treatment, the difference is small and not believed to have had much impact on overall shrimp production between the two treatments. The mean individual shrimp weights were similar between treatments and similar to those seen in previous indoor shrimp production studies (Fleckenstein et al., 2018;Ray & Lotz, 2017). ...
Inland production of marine shrimp provides high‐quality shrimp to consumers. Artificial sea salts are added to local water to provide the essential minerals required by shrimp; however, commercial salts are expensive. An experiment evaluated different combinations of a homemade, least‐cost salt mixture (LCS) and a common commercial sea salt (CSS). The LCS formulation was made using six salts: NaCl, MgSO4, MgCl2, CaCl2, KCl, and NaHCO3. The five treatments in this study were as follows: 100% LCS, 75/25% LCS/CSS, 50/50% LCS/CSS, 25/75% LCS/CSS, and 100% CSS; each treatment was randomly assigned to four 1 m³ tanks. There were some significant differences between treatments in DO, pH, and nitrite concentration, but these differences were subtle. There were no significant differences in mean weight, growth rate, FCR, biomass, or survival of shrimp. The 100% LCS salt formulation was 65% less expensive than the CSS mixture by weight, and the cost per kg of shrimp produced was 57% lower using the LCS. In fact, even the 50/50% treatment had a significantly (p ≤ 0.05) lower cost kg‐1 shrimp than the 100% CSS treatment. These results indicate that this LCS formulation is suitable for intensive shrimp production, and the cost savings may be substantial.
... L. vannamei of 1 to 9 g reared at 120 animals m −2 , biofloc contributed 18 to 29% of their daily N retention (Burford et al., 2004). Similarly, Ray and Lotz (2017) reported that biofloc material contributed with 28% C and 59% N found in the tail muscle of L. vannamei of 2.6 ± 0.1 g reared for 8 weeks under 250 animals m −3 . ...
... However, the average contribution (8.95 ± 6.60%) of biofloc to shrimp growth when all dietary treatments are considered was much lower than other studies. Ray and Lotz (2017) reared L. vannamei of 2.6 ± 0.1 g BW for 8 weeks in biofloc and clear-water (CW) systems with a 35%-CP commercial feed. They found that in the biofloc system, biofloc material may have contributed 28 and 59% of the C and N in shrimp tissues, respectively. ...
Studies have demonstrated that biofloc can be used as food or as a nutrient source for farmed shrimp, either through direct intake from culture water or as an ingredient. We investigated the nutrient value and contribution of biofloc to the growth of L. vannamei fed essential fatty acid (EFA)- and amino acid (EAA)-restrained diets. A total of 6144 shrimp of 3.04 ± 0.43 g body weight (BW) were reared in 48 outdoor tanks of 1 m³ under 128 animals m⁻³ and fed 12 diets during 72 days in a biofloc-dominated system. Diets contained 31.54 ± 0.98% crude protein (CP, % dry matter basis) and 7.91 ± 0.46% total lipids. Dietary EFA and EAA were manipulated by progressively reducing the inclusion of fish oil from 2.00 to 1.00 and 0%, and fish meal from 12.00 to 8.00, 4.00, and 0%, resulting in a 3 × 4 fish oil-fishmeal factorial design (diets 2–12, 2–8, 2–4, 2–0, 1–12, 1–8, 1–4, 1–0, 0–12, 0–8, 0–4, and 0–0; % of the diet; as-fed). The relative contribution of biofloc and diets to shrimp growth was estimated using the stable carbon isotope (δ¹³C) mass spectrophotometry analysis. At harvest, shrimp final survival (79.4 ± 7.3%), yield (1407 ± 125 g m⁻³), FCR (1.88 ± 0.18), and AFI (20.6 ± 0.3 g of diet stocked shrimp⁻¹) were unaffected by dietary treatment. However, weekly growth was significantly lower with diets deprived of fish oil and containing lower levels of fish meal (0 and 4%) compared to higher levels (8 and 12%). Shrimp BW was significantly affected by the dietary inclusion of both fish oil and fish meal and their interaction, varying from 13.08 ± 0.72 (diet 0–0) to 14.82 ± 0.23 g (diet 2–12). Biofloc contained a high ash content (58.09 ± 3.01%), low lipid levels (1.67 ± 0.32%), and a 7.71–18.05% CP content. The isotopic signatures in shrimp muscle at harvest became more negative compared to values observed at stocking, approaching values of the diets used. We estimated that the experimental diets contributed on average with 91.5 ± 7.4% of the shrimp's carbon growth, with the remaining attributed to biofloc. Our results demonstrated that juvenile L. vannamei reared in a biofloc-dominated system derive the bulk of their nutrition and growth from artificial food. Biofloc acts as a supplemental food source, but provides a limited source of key dietary nutrients to shrimp growth.
... Therefore, substantial risks are involved when culturing animals with BFT (Furtado et al., 2014), and farmers must consider this before implementation. Typically, species that benefit the most from BFT are those that are capable of collecting and consuming bioflocs, especially crustaceans (Cardona et al., 2015;Ray and Lotz, 2017). However, some fish species have also benefited in terms of growth and/or immunity including tilapia, Oreochromis niloticus (Avnimelech and Kochba, 2009), silver carp, Hypophthalmichthys molitrix, bighead carp, Aristichtys nobilis (Zhao et al., 2014) and lemon fin barb hybrids, Hypsibarbus wetmorei ♂ × Barboides gonionotus ♀ . ...
... Hematoxylin and eosin (a, b, c) × 200 magnification; and Periodic-acid Schiff (d, e, f); × 100 magnification. et al., 2015) and L. vannamei at 27.7 and 58.5 %, respectively (Ray and Lotz, 2017). It was also found that bioflocs could contribute up to 25 % of nitrogen in O. niloticus, compared to a normal ration of commercial food (Avnimelech and Kochba, 2009). ...
Biofloc technology (BFT) can potentially enhance growth and provide supplemental nutrition to some fish species, but this has not been investigated in bluegill Lepomis macrochirus juveniles. In this study, L. macrochrius juveniles were cultured in a clear-water (CW) system versus BFT when using either corn starch (BFT-Sta) or sucrose-sugar (BFT-Sug) for 32 days at a carbon (C) to nitrogen (N) ratio of 15. After 32 days, water composition of cultivable bacteria were identified using molecular techniques while the survival, growth, histopathology, biochemical composition, and contribution of C and N from bioflocs (based on stable isotope analysis) to L. macrochrius were determined. In the CW system, Escherichia coli was detected but not in the BFT tanks, whereas Aeromonas hydrophila was present in the BFT tanks but not in CW. Fish obtained C and N from bioflocs at 4.11 % and 9.5 % in the BFT-Sta treatment, respectively, and 18.8 % and 1.4 % in the BFT-Sug treatment, respectively. A temporary loss of aeration in the BFT treatments led to dissolved oxygen (DO) plummeting, leading to 50 % mortality, which is indicative of the risk involved when using BFT but also the tolerance of L. macrochrius to temporary low DO. BFT also significantly reduced L. macrochrius growth, which was likely compounded by consistently elevated ammonia and reduced feed intake/feeding activities. The nutritional contribution of bio-flocs to L. macrochirus along with no abnormal gill histopathology suggests BFT could have great potential for this species.
... Our understanding of the innate immune response of shrimp, when cultured under biofloc conditions, is still in its early stages. Besides, the RAS-no-BF for rearing shrimp has shown similar productive capacity to the biofloc systems (Esparza-Leal et al., 2015;Ray and Lotz, 2017). Hence, in this study, we evaluated whether the heterotrophic micro-ecosystem (biofloc system) and RAS-no-BF promote the transcription of immune genes in L . ...
... At the beginning of the bioassay, the physicochemical parameters were kept within acceptable ranges for rearing L . vannamei in BF and no-BF cultures (Esparza-Leal et al., 2015;Ray and Lotz, 2017;Schveitzer et al., 2018). ...
Background:
Shrimp farming is evolving from semi-intensive to hyper-intensive systems with biofloc technology and water recirculation systems.
Objective:
To evaluate the transcriptional response promoted by biofloc on shrimp (Litopenaeus vannamei) under a recirculating aquaculture system (RAS).
Methods:
Quantitative real-time RT-PCR was used to monitor seven key genes related to the immune system in shrimp post-larvae, reared in a RAS with and without biofloc (BF and no- BF). In addition, we present for the first time nucleotide sequences of ADP-ribosylation factor 4 (LvArf4) from Litopenaeus vannamei.
Results:
Transcripts for penaeidin3 (Pen3), penaeidin4 (Pen4), crustin, and Toll receptor (LvToll) genes were up-regulated between 3 and 24 h in both systems, and tumor necrosis factor receptor-associated factor 6 (TRAF6) in no-BF as an early response. Regarding differential expression between treatments, 13 occurrences were encountered. Nine that were higher in BF than in no-BF and four higher in no-BF than in BF. In some sample times, expression of Pen3, crustin, LvToll, TRAF6, IMD, and LvArf4 was higher in BF than in no-BF and in others, expression of Pen3, Pen4, and TRAF6 was higher in no-BF than in BF.
Conclusions:
BF modulates the transcription of genes related to the immune response in shrimp as an early response. However, the RAS with no-BF promotes a similar response.
... However, intensive fi sh farming causes quick deterioration of water quality due to the accumulation of toxic substances which are lethal to fi sh. Biofl oc Technology (BFT) can however, provide fi sh production at high stocking density in a condition that is sustainable and biologically safe (Ray et al., 2010;Zhao et al., 2012;Schveitzer et al., 2013) as it allows conversion of toxic ammonia, excreted by the fi sh into the rearing system to safer nitrate products, besides, the heterotrophic microbes which becomes a source of natural food for the fi lter-feeding fi shes and shrimps (Avnimelech, 2009;Cardona et al., 2015;Ray and Lotz, 2017). Several past studies have demonstrated suitability of BFT for the farming of Pacifi c white-leg shrimp (Penaeus vannamei) and Nile tilapia (Oreochromis niloticus) owing to their better filter-feeding efficiency in the biofloc system (Xu et al., 2012;Martins et al., 2020;Nguyen et al., 2021;Suarez-Puerto et al., 2021). ...
The performance of hatchery-produced and pellet-feed-weaned fingerlings of striped murrel, Channa striata (Bloch, 1793) was assessed in the biofloc tanks for growth and survival, in a subtropical climate. The rearing was undertaken in two phases with an increase in fish size. In the first phase, fingerlings (weight 1.94±0.71 g, length 6.29±0.81 cm) were stocked @ 200 m-3 in the biofloc tanks, which were reduced to 15 m-3 in the second phase using the same stock. The fish attained a length of 25.44±1.81 cm and weight of 149.60±28.58 g in 10 months with overall survival of 93% at the end of the second phase. The total fish biomass recorded was 9.7 kg m-3 at the final harvest. The growth parameters were found temperature-dependent, which recorded 15±1.0 to 28±1.5ºC and 'W' values were found to follow Fulton's cube law during the entire culture period. The exponent (b) of 3.278 was recorded as the highest in July 2020 and lowest at 2.210 in December 2020. The lowest R2 was 0.768 and highest 0.943 during December and April respectively whereas, the recorded ‘K’ of 0.611 was the lowest in winter and highest being 0.908 in August. The study demonstrated a higher culture potential of striped murrel with hatchery-produced and feed-weaned seed in the biofloc system with zero-water exchange. Keywords: Condition factor, Fulton's cube law, Growth, Production, Survival, Zero-water exchange
... Particularly, for systems dependent on sunlight, the performance of BFT can vary according to seasonal changes in daylight duration [29]. In addition, the inconsistent nitrogen cycle and reduced activity of effective microorganisms in the water may cause water pollution due to accumulation of nitrite, ammonia and nitrate in BFT, potentially harming the health of aquaculture organisms [30]. In order to counteract the rapid decrease in dissolved oxygen caused by the excessive proliferation of beneficial microorganisms, BFT systems require the use of aeration devices to maintain high levels of dissolved oxygen, which can result in higher facility costs [31]. ...
Some aspects of traditional aquaculture have negative impacts on the aquatic environment, leading to pollution and disease outbreaks in farmed organisms. Biofloc technology (BFT) is a closed aquaculture system that utilizes specific microbial communities to remove ammonia emitted from aquaculture organisms or adds carbon to the aquaculture system to improve water quality. BFT has benefits, such as increasing production and improving water quality, and reducing disease spread and pollution, without the need for water exchange. However, there are disadvantages, such as rapid changes in water quality due to accumulation of dissolved nutrients and total suspended soils (TSS) and the requirement for expensive aeration equipment to maintain dissolved oxygen. BFT can be enhanced in value and efficiency by combining it with other aquaculture technologies, such as aquaponics and vertical aquaculture to overcome the disadvantages. The integration of biofloc with technologies from the fourth industrial revolution holds potential for further development, while aquaponics and vertical farming can eliminate geographical limitations and accelerate the urbanization of aquaculture. The integration of aquaponics and vertical aquaculture with BFT has potential for development, accelerating the urbanization of aquaculture and removing geographic limitations.
... Closed Recirculating System (CRS) menerapkan metode pengelolaan lumpur, membuang secara terus menerus yang kemudian air buangan tersebut di olah kembali. CRS biasanya dilengkapi dengan kolam pengendapan (Ray & Lotz, 2017;Permana et al., 2019). Sejalan dengan pernyataan Supono, (2017), air buangan dari tambak dengan system CRS diolah kembali melalui kolam pengendapan, kolam perlakuan secara biologi (biofiltration pond), dan kolam rekondisi (reconditioning pond) dengan (protein sekimer), sebelum masuk ke kolam budidaya (culture pond) (Zulkarnain, 2020; Hastuti et al., 2018). ...
Masalah utama pada budidaya udang secara intensif adalah menurunnya kualitas air yang layak selama pemeliharaan udang dan munculnya penyakit. Masalah ini mengakibatkan menurunya produktifitas udang vaname. Salah satu upaya yang dilakukan adalah melalui penerapan metode pengelolaan lumpur, dengan tujuan untuk mengurangi tumpukan lumpur didasar tambak intensif. Metode pengelolaan lumpur antara lain sistem, CRS (Close Resirculating System), semi close dan bioflok. Metode penulisan yang digunakan yaitu studi pustaka, untuk analisis data dengan membandingkan rata rata data produksi dan kualitas air pada masing masing sistem. Pengelolaan lumpur pada sistem CRS, memindahkan sisa bahan organik kedalam kolam pengendapan. Pada sistem semi close, membuang lumpur secara berkala melalui central draine. Pengelolaan lumpur pada sistem bioflok, memanfaatkan bakteri heterotopik untuk mengolah sisa bahan organik. Average Daily Gain (ADG) terbesar terdapat pada sistem bioflok sebesar 0.16 g/day dan terkecil pada sistem semi close sebesar 0,11 gr/day. Survival rate (SR) tingkat kelulus hidupan tertinggi pada sistem bioflok dengan SR mencapai 88%, dan terendah pada sistem CRS yaitu 81%. Feed Convertion Ratio (FCR) terbaik pada sistem bioflok yaitu nilai FCR mencapai 1.26, berikutnya sistem CRS dengan FCR 1.33, dan pada sistem semi close nilai FCR mencapai 1.93. Sistem pengelolaan lumpur terbaik dari ketiga sistem tersebut yaitu sistem bioflok. Rata-rata data kualitas air harian dari ketiga sistem tersebut masih dalam kondisi optimal, walaupun pada parameter amonia, nitrit, dan nitrat terpaut tinggi, namun pada tingkat kelulus hidupan udang ketiga sistem tersebut masih diatas 80%.
... Closed Recirculating System (CRS) menerapkan metode pengelolaan lumpur, membuang secara terus menerus yang kemudian air buangan tersebut di olah kembali. CRS biasanya dilengkapi dengan kolam pengendapan (Ray & Lotz, 2017;Permana et al., 2019). Sejalan dengan pernyataan Supono, (2017), air buangan dari tambak dengan system CRS diolah kembali melalui kolam pengendapan, kolam perlakuan secara biologi (biofiltration pond), dan kolam rekondisi (reconditioning pond) dengan (protein sekimer), sebelum masuk ke kolam budidaya (culture pond) (Zulkarnain, 2020; Hastuti et al., 2018). ...
The main problem in intensive shrimp pond culture is a decrease in the quality of proper water during shrimp rearing and the emergence of disease. This problem resulted in decreased productivity of vaname shrimp. One of the efforts made is through the application of sludge management methods, with the aim of reducing the pile of sludge at the bottom of intensive ponds. Sludge management methods include the system, CRS (Close Resirculating System), Semi Close, and biofloc. The writing method used is literature study, for data analysis by comparing the average production data and water quality in each system. Sludge management in the CRS system, move the remaining organic material into the settling pond. In semi close system, remove sludge periodically through central draine. sludge management in the biofloc system, utilizing heterotopic bacteria to treat the remaining organic matter. The largest Average Daily Gain (ADG) is present in the bioflocked system at 0.16 g / day and the smallest in the semi close system at 0.11 g / day. Survival rate (SR) is the highest survival rate in the biofloc system with SR reaching 88%, and the lowest in the CRS system, namely 81%. The best Feed Convertion Ratio (FCR) in the biofloc system is that the FCR value reaches 1.26, the next is the CRS system with FCR 1.33, and in the semi-close system the FCR value reaches 1.93. The best sludge management system of the three systems is the biofloc system. The average daily water quality data of the three systems are still in optimal conditions, although the parameters of ammonia, nitrite, and nitrate are high, but at the survival rate of the shrimp the three systems are still above 80%.
... Most recent development in RAS design are towards environmental sustainability (Xiao et al., 2018). This study is based on the outcome of the previous results which focussed on the technical improvements of water quality in an intensive culture system (Ray and Lotz, 2017;Hassan et al., 2018aHassan et al., , 2018b. The main technology used in current experiment is biological filters. ...
Base on the principle of developing a suitable aquaculture system that will fit the present climate and environmental challenges to enhance breeding and production in aquaculture. Against the backdrop of issues connected to water quality in recirculating aquaculture system which has negative impact on the fish comfort, feeding rate and blood biochemistry, this may later affect its growth performance and general wellbeing. Although, the rate of waste disintegration and the bacteria species present in the filter system determine the physicochemical parameters of the treated water, which further affect the biological characteristics of the fish. This study intends to reveal the effect of biological filtration media (wood coal, rice hulls and wheat hay) on water properties and its further effects on growth performance, plasma biochemistry, liver and gills histopathology of common carp in RAS. After the acclimation interval, 24 tanks were stocked with 8 fish average initial weight of 15.74 g. However, treatments were assigned to each tank at random sampling to make four treatments. The results showed a significant effect on Common carp growth and body biomass, for those with filter media compared to the control. Though, a better growth performance of Common carp culture in water exposed to wheat hay and rice hulls were recorded at significant level with lower FCR. Hence improvement in fish productivity was observed in the treatments compared to the control. Moreover, there are significant changes on cell counts, and plasma biochemistry parameters. In synopsis, the study reveals the benefits in using additional media such as wheat hay and rice hulls as a biological filter media to improve water quality and growth performance of common carp in aquaculture. The use of this new media should be encourage since the installation of this biological filter media is simple, affordable and can be retrofitted into existing systems, to increase water management and aquaculture productivity.
... Once the aforementioned improvements in the system design are implemented, the full nutritional advantages of flocs would be achieved. Some of the reported nutritional advantages of using BFT instead of RAS are: (i) reduced feed conversion ratio 74,169,170 ...
FLOCponics is an alternative type of aquaponics that integrates biofloc technology (BFT) with soilless plant production. The aims of this paper are to present a detailed overview of the FLOCponics system's designs and performance, discuss their sustainability, highlight the current challenges, and give directions for future research. Data sources include papers containing the keywords bioflocs and hydroponics, aquaponics and/or plant production. In view of the small number of publications and the lack of standardization in experimental design and system setup, it was concluded that FLOCponics is still in its initial research stage. With respect to the animal and plant yields in FLOCponics, inconsistent results were found. Some investigations presented better or similar yield results in this system compared to traditional cultures, while others found the opposite. One of the key challenges of using FLOCponics is the effective control of solids. Refining the system's design was the main recommended improvement. Moreover, this paper highlights that the commercial application of FLOCponics will require extensive research that clarifies its technical and economic aspects, originating from experimental or pilot‐scale setups with characteristics similar to commercial production. This review provides and discusses information that can be useful for the effective development of FLOCponics, guiding further research to make FLOCponics commercially feasible and thus contributing to sustainable aquaculture production.
... Thí nghiệm được bố trí trên hệ thống tuần hoàn gồm 3 bể nuôi 500 L, bể lắng cơ học 500 L và bể lọc sinh học 500 L. Trong đó, bể lọc sinh học được thiết kế theo Ray and Lotz (2017) chứa 20% thể tích giá thể di động (moving bed bioreactor [MBBR], Mã hiệu PE50; kích cỡ: Φ25 × 4; diện tích bề mặt: 600 m²/m³). Các bể nuôi và bể giá thể được duy trì sục khí liên tục và chứa 80% thể tích nước ở độ mặn 15‰. ...
Đề tài được thực hiện nhằm đánh giá khả năng chuyển hóa đạm của các chủng vi khuẩn nitrate hóa chọn lọc từ ao nuôi tôm sử dụng cho hệ thống lọc tuần hoàn trong nuôi tôm thẻ trên bể. Thí nghiệm gồm 4 nghiệm thức, mỗi nghiệm thức lập lại 3 lần. Đối chứng: không bổ sung vi khuẩn; 2) Nghiệm thức 1: bổ sung vi khuẩn AOB TB7.2; Nghiệm thức 2: bổ sung vi khuẩn NOB TV4.2 và Nghiệm thức 3: bổ sung hỗn hợp vi khuẩn AOB TB7.2 và NOB TV4.2. Kết quả cho thấy việc bổ sung vi khuẩn AOB TB7.2 và vi khuẩn NOB TV4.2 vào bể lọc sinh học trong hệ thống tuần hoàn làm giảm hàm lượng các khí độc ammonia và nitrite trong bể nuôi, tăng tỉ lệ sống, khác biệt có ý nghĩa thống kê đồng thời tái sử dụng được nguồn nước trong suốt chu kỳ nuôi, giảm thiểu tác động đến môi trường bên ngoài. Bổ sung kết hợp AOB TB7.2 và NOB TV4.2 quá trình nitrate hóa diễn ra nhanh hơn so với bổ sung đơn dòng. Quá trình nitrite hóa và nitrate hóa diễn ra sớm hơn ở các nghiệm thức có bổ sung vi khuẩn so với đối chứng (nitrite hóa và nitrate hóa là 7 ngày và 14 ngày; 14 ngày và 35 ngày lần lượt ở nghiệm thức bổ sung vi khuẩn và đối chứng).
... The author's findings have opened the door for more studies on the TAN removal in MBBR at a particular scale to better design and dimension commercial-scale RAS. In another study, a performance comparison was conducted between the biofloc technology (BFT) and marine RAS coupled to MBBR for maintaining good water quality for shrimp production (Ray & Lotz, 2017). Concerning water quality and shrimp survival, the BFT resulted in the lowest shrimp survival (28%) than RAS attached to the moving bed bioreactor. ...
In recent years, government investments in implementing restrictive public policies on the treatment and discharge of effluents from the aquaculture industry have increased. Hence, efficient and cleaner methods for aquaculture production are needed. Recirculating aquaculture systems (RAS) offers water conservation by recycling the treated aquaculture water for reuse. RAS wastewater treatment using a moving bed bioreactors (MBBRs) process has been considered well suited for maintaining good water quality, thereby making fish farming more sustainable. Currently, improvements were achieved in tackling the influence of salinity, organic matter, disinfectant, and bioreactor start-up process on the MBBR performance efficiency. This review highlights an updated overview of recent development made using MBBR to treat the residual water from RAS. Precisely, nitrification and simultaneous nitrification-denitrification (SND), and other hybrid processes for nitrogen removal were elucidated. Finally, future challenges and prospects of MBBRs in RAS facilities that need to be considered were also proposed.
... Additionally, using low-salinity systems may reduce the costs of imported seawater or artificial sea salts (Ray and Lotz, 2017a). Evidence that whiteleg shrimp can grow and survive in brackish water has already been reported (Samocha et al., 2004;Ray and Lotz, 2017b;Pinheiro et al., 2020). However, no studies to date have evaluated the effect of reduced dietary protein levels combined with low water salinity on shrimp performance and sensorial attributes in BFT. ...
A study was conducted to evaluate the sensorial attributes and zootechnical performance of whiteleg shrimp (Litopenaeus vannamei) juveniles cultured in biofloc technology (BFT) with varying water salinities and proteinous feed. The experiment was conducted at two salinity levels viz., 5 ppt and 30 ppt each with two different proteinous feeds viz., 25% and 35% crude protein (CP), in a completely randomized factorial experimental design. Shrimp juveniles (average weight: 1.07 g) were stocked uniformly at the density of 233 shrimp m⁻³ in sixteen 60-L experimental tanks and reared for nine weeks. At the end of culture, all shrimps were harvested from the tanks and zootechnical parameters were recorded. The sensorial attributes viz., aroma, color, flavor, texture, and overall acceptance of shrimps reared in BFT under the tested treatments and in traditional earthen pond culture system were compared. In terms of zootechnical parameters, survival was similar among all treatments. The shrimp growth and productivity were significantly affected by either salinity and protein levels of feed. The same trend was observed for the feed conversion ratio and protein efficiency ratio. The highest shrimp growth (final weight: 4.08 g) was achieved in 30 ppt water with 35% CP. The sensorial attributes of shrimp were similar in all experimental treatments including those reared in traditional earthen pond. The results suggested that 30 ppt of water salinity and 35% of dietary crude protein promoted superior shrimp performance as compared to 5 ppt and 25% CP. Additionally, the current study revealed that sensorial attributes of L. vannamei cultured in BFT did not change regardless of the salinity (5 ppt and 30 ppt) and/or the dietary crude protein (25% and 35% CP), and was comparable to those reared in traditional earthen ponds.
... The costs of buying and operating additional filtration components for a CW system may make this a more expensive and technically vulnerable approach compared to e.g. a simple open tank bio-reactor. However, the nitrification cycle in CW systems may be more stable than in BFT systems due to the controlled environment provided by the external mechanical and biofilters (Ebeling et al., 2010;Ebeling and Timmons, 2012;Ray and Lotz, 2017). ...
A 9-week feeding experiment was conducted to evaluate different dietary protein levels in juvenile Nile tilapia reared in either a biofloc (Bio-RAS) or clear water recirculating aquaculture system (CW-RAS). The fish were fed four isoenergetic (19 MJ kg⁻¹) diets with graded levels of a fixed mixture of three protein sources (animal, plant, and microbial origin) and containing 23, 27, 31 or 35% crude protein. Triplicate groups of 20 juvenile tilapia (initial weight: 39.1 ± 2.5 g) were randomly assigned to 24 identical conical 500-L tanks equipped with feed waste traps. Twelve of the tanks were supplied with clear water purified by a mechanical and biological filter, denoted CW-RAS, and on average 15% daily replacement of water. The other 12 tanks were supplied with a biofloc suspension, maintained by a bioreactor system, denoted Bio-RAS, where the mechanical and biological filters were replaced with four serial 10 m³ open bioreactor tanks. In this later system only evaporated water was replaced. The bioreactor tanks were initially inoculated with Bacillus subtilis, and nutrients were supplied to achieve a C: N ratio of 10, supporting heterotrophic bacterial growth. Feed and protein intake, weight gain, specific growth rate, protein efficiency of fish in all treatments, and biomass of micro components in the bioreactor tanks, as well as apparent digestibility of dietary components, were determined at end of the experiment. Growth, feed intake and protein efficiency, especially if retention of the floc was included, was overall higher in the Bio-RAS than in the CW- RAS system. Feed conversion was influenced both by protein level and by the availability of biofloc, with a general lower value in the Bio-RAS and fish given higher protein containing diets. Apparent digestibility of total protein did not vary with the rearing system but was higher with higher dietary levels of crude protein. No significant effect was found for mortality or body index, except for hepato-somatic index and intestinal quotient index, with the latter being significantly higher in the fish given access to biofloc. In all fish given access to biofloc, given all other factors being equal, displayed higher and more feed efficient growth than fish kept in clear water with only access to fabricated diets. Our results tally with other studies using biofloc tank technology and reports from more commercial settings indicating that our data is valid also at a more general level.
... The biochemical composition of bioflocs includes protein, lipids, carbohydrate, ash, fiber, amino acids, fatty acids, cholesterol, antioxidants as well as some bioactive and derivative compounds, such as organic acids, polyhydroxy acetate and polyhydroxy butyrate (Ahmad et al., 2017;Cardona et al., 2016;Crab et al., 2010;Dauda et al., 2018;Ju et al., 2008). Some aquacultured animals have utilized the bioflocs, most notably prawns (Asaduzzaman et al., 2010;Crab et al., 2010;Pérez-Fuentes et al., 2013), shrimp (Cardona et al., 2016(Cardona et al., , 2015Ray et al., 2010;Ray and Lotz, 2017), tilapia (Pérez-Fuentes et al., 2016), filterfeeding carps (Zhao et al., 2014) and bluegill, Lepomis macrochirus (Fischer et al., 2020). The utilization of biofloc may contribute to increase survival and growth by enhancing digestive enzyme activities (Cardona et al., 2015;Long et al., 2015) and/or improve immunity (Kim et al., 2014;(Miao et al., 2017b). ...
Improved sustainable aquaculture can be achieved through biofloc technology (BFT) by reducing feed input and water use. Although BFT is considered a viable culture strategy to various crustaceans, including Macrobrachium rosenbergii, the influence of salinity has not received much attention. The aim of this study was to investigate the effects of increasing salinities of BF0, BF5, BF10, and BF15 PSU on Macrobrachium rosenbergii post larval (PL) growth performance and proximate composition in a biofloc system as well as water quality, total bacteria and Vibrio spp. and zooplankton abundance/composition. A carbon: nitrogen ratio was maintained at 10 by maize starch additions. Each tank contained 500 prawns (42.5 ± 5.6 mg) in triplicate. Growth was similar (p > 0.05) in BF0, BF10 and BF15, but was significantly lower in BF5. The best FCR was observed in BF15 and BF10. PL survival was significantly (p < 0.05) higher at BF10 and BF15 than in BF5 and BF0. Higher gross return, net return and benefit cost ratio were obtained (P < 0.05) at BF10 and BF15 than in BF0 or BF5. Whole-body crude protein was significantly elevated in BF15 than all others. Nitrate-N, pH, floc volume and VSS were unaffected by salinity (p > 0.05); however, at weeks 3 and 4, ammonia-N was higher in BF0 (p < 0.05). Total bacteria density and Vibrio spp. were significantly (p < 0.05) higher at BF10 and BF15 than in BF5 and BF0. Total zooplankton density was higher (P < 0.05) at BF15. This study demonstrates that a salinity of 15 PSU improved survival, production economics and protein content of M. rosenbergii, which was likely linked with a greater zooplankton abundance in the biofloc-based system.
... The poor performance in floc-based trial may have been due to elevated ammonia concentration (2.77 mg L À1 ), which may have caused oxidative stress and reduced shrimp performance (Pinto et al. 2016). Ray and Lotz (2017) also found that ammonia and nitrite concentrations were higher, and feed utilization and survival rates were lower, in shrimp (L. vannamei) PL in BFT systems than in clear-water RAS. ...
In face of the shortage of, and competition with, land and water, the sustainability of aquaculture will have to depend on vertical development, through improving production environments, increasing productivity and enhancing aquaculture technologies. Biofloc technology (BFT) has emerged as new alternative for sustainable aquaculture, which could contribute to FAO Sustainable Development Goals (SDGs) related to food security. Extensive research has been carried out on the development and application of BFT in aquaculture since early 1990s, with emphasis on shrimp culture. Over 40% of BFT publications in aquaculture were directed to shrimp farming. Therefore, I strongly believe that the accumulated knowledge on the applications of BFT in shrimp farming and the experience gained, especially during the last 10 years (2010–2020), are now more than worthy of critical review and analysis. This review summarizes the most update knowledge on the use of BFT in different marine shrimp and freshwater prawn aquaculture. Emphasis has been on factors affecting shrimp production in BFT systems, integration of biofloc‐based shrimp farming with other aquatic farmed species, nutritional value of bioflocs as a natural food or feed ingredient for farmed shrimp and prawn, the application of BFT in different rearing phases, the use of biofloc as a natural probiotics and their effects on shrimp health and physiological functions, economic considerations and commercial applications of BFT‐based shrimp aquaculture, and the major challenges facing shrimp farming in biofloc systems.
... This study is based on previous developments in RAS that focused on technical improvements in water quality within the RAS (Foesel et al., 2008;(Hasan & Rahman, 2016;Hassan et al., 2019;Peirong & Wei, 2011;Peirong & Wei, 2011;Ray & Lotz, 2017;Vivanco-Aranda et al., 2011;Xiao et al., 2018). There exists a need for a proper filling for the biological bed to remove toxic nitrogen compounds (Sikora et al., 2018). ...
This work aims to develop a suitable aquaculture system to solve issues pertaining
to water quality in recirculating aquaculture systems (RAS) thereby improving fish
growth performance and their feed conversion ratio (FCR). It is known that the efficiency
of nutrient decomposition depends on the amount and species of bacteria
present in the filter, and these can in turn be regulated by the pH. Our study shows
that the significant increase in pH from 7.45 to 7.51 and 7.47 is achieved after the
water was filtered through sawdust and wood wool respectively. At the same time,
nitrite concentrations were found to have significantly decreased from 0.06 ppm in
the control to 0.01 ppm in the sawdust treatment. Changes in the physical–chemical
properties of treated water affect the biological properties of the organisms. It was
found that the average final body weight for fish in the wood wool treatment 30.96 g
and fish in the sawdust treatment 31.44 g was significantly higher compared to that
for the fish in the control treatment 28.42 g. The use of sponge, wood wool or sawdust
resulted in significantly lower FCR and therefore better fish productivity in RAS.
At the same time, the red blood cell count, plasma urea, plasma creatinine, plasma
albumin, and GOT and GPT were significantly higher in fish in the plastic, sponge,
wood wool or sawdust treatment compared to the control treatment. In summary,
this study demonstrates the benefits of using sponge, wood, wool and sawdust as
biofilter media for aquaculture.
... Carbon (δ13C) and nitrogen (δ15N) isotope ratios can be measured in bioflocs, feed and shrimp tissue in order to determine the contribution of each food source to shrimp (Ray and Lotz, 2017). Previous studies using this technique with Litopenaeus stylirostris showed that bioflocs could supply 37 to 40% of C and N necessary for growth (Cardona et al., 2015). ...
Biofloc technology (BFT) is considered one of the most promising methods for the sustainable development of shrimp culture. Bioflocs keep the water quality at good standards and represent a complementary food source, allowing the production of high stocking densities of the white shrimp Litopenaeus vannamei. Microorganisms present in flocs are an important source of lipids and proteins; however, laboratory observations indicate that floc consumption is not the same for all shrimp stages. We have, therefore, established the hypothesis that bioflocs are more important food sources for larger shrimps that can better manipulate the flocs and pick up and consume specific microorganisms. The stable isotope technique has been recently applied in aquaculture to quantify the importance of different food sources to the growth of target species. In this study, this technique was employed in two experiments in order to test the established hypothesis, measuring biofloc consumption by 0.01 g L. vannamei postlarvae in nursery tanks and by 0.80 g shrimp in the grow-out phase. Both experiments were conducted in greenhouse tanks (12–800 L) with a stocking density of 2000 shrimp/m³ in the nursery phase and 400 shrimp m³ in the grow-out phase. The experiment was designed with two treatments with four replicates each: (I) F, with feed only; and (II) BF, with bioflocs and feed. Shrimp were fed a commercial diet twice a day in the nursery and grow-out stage with 40 and 38% crude protein, respectively. Differences were found between water quality parameters for pH, ammonia, nitrite, nitrate, phosphate, SST and turbidity (p˂0.05).Zootechnical performance also showed differences between shrimp of different treatments for final weight, final biomass, survival, yield m³ and m² (p˂0.05). The results of the stable isotope technique indicate that bioflocs contributed 22–43% C and 0–43% N to the shrimp tissue composition during the nursery phase, whereas in the grow-out phase, the contribution of bioflocs varied between 63 and 100% C and 35–86% N. Differences in the abundances of Oocystis sp., pennate diatoms and flagellates (p˂0.05) indicate that these microorganisms were preferentially consumed by larger shrimp. Thus, the results of this study corroborate the hypothesis that the contribution of bioflocs as a supplementary source of natural food depends on the size of the shrimp.
... Although BFT is an effective water quality management strategy, bioflocs may provide supplemental nutrition to some aquatic animals capable of collecting these small particles, such as shrimp (Cardona et al., 2015;Ray and Lotz, 2017), tilapia (Pérez-Fuentes et al., 2016) and filter-feeding carps (Zhao et al., 2014). The consumption of additional nutrients may contribute to improved survival/growth by enhancing digestive enzyme activity (Long et al., 2015;Cardona et al., and juveniles as well as resistance to infectious compared to those cultured in clear water systems (Ekasari et al., 2016;Dauda et al., 2017Dauda et al., , 2018a. ...
Biofloc technology (BFT) relies on adding organic carbon, often in the form of sugars or starches, to encourage heterotrophic bacteria that convert otherwise toxic ammonia/nitrite into potentially consumable biomass known as ‘bioflocs’. The subsequently higher turbidity may be inappropriate for more carnivorous fish, but research in this area is limited. In this study, largemouth bass Micropterus salmoides juveniles (7.27 g) were cultured in either a clear-water system (CWS) or BFT system. Each week, a sub-sample of M. salmoides was measured for length, weight, hepatosomatic index (HSI) and hemoglobin. After 4 weeks, M. salmoides were measured for productivity, muscle/liver biochemical composition, gill Na+/K+-ATPase/H+-ATPase activities, plasma cortisol, as well as the histomorphology of the gills and liver. Within 7 days, Bacillus spp., Acinetobacter spp. and Enterobacter spp. were detcted in the BFT tanks, but were replaced with Planococcus spp. by week 4. Despite consistently lower nitrogenous waste levels in BFT, growth became significantly reduced, which was likely due to elevated circulating cortisol depressing feed intake. Livers from fish in BFT showed some local inflammation while nearly all the secondary gill lamellae on the gills were shorter. This latter finding may have contributed to significantly elevated and depressed hemoglobin level and gill Na+/K+-ATPase activity in BFT, respectively, after 4 weeks. Although survival was similar between treatments, long-term culture of M. salmoides with BFT is not advisable likely due to excessive suspended solids accumulation, including mucus. However, BFT may be a short-term strategy to reduce excessive nitrogenous waste levels in times of limited access to water.
... ± 6.1 %) and second (76.7 ± 3.5 %) crops of water reuse with intermittent nitrification and denitrification treatments. Compared to previous studies, the survival percentages of shrimp post-larvae in this study were close to the rates in marine RASs (approximately 25-30 PSU) with a floating biofilter (Leungprasert and Chanakul, 2010) and a moving bed bioreactor (MBBR) (Ray and Lotz, 2017). ...
... Tilapia is well documented as efficient in phytoplankton filtering and as well-adapted to feed on flocculated bacteria (Avnimelech, 2015;Bhujel, 2014). Furthermore, the increased protein efficiency ratio of the biofloc fish was most likely an effect of the recirculation of nitrogen lost from the fish, recaptured by the microbes and then re-ingested by the fish (Ray and Lotz, 2017). It is important to underline that we actually used a very simple and non-optimised biofloc system, that could be recreated at commercial farm level even in resource-poor areas, and still found significant improvements in important production variables, such as growth, feed utilisation, protein efficiency ratio and survival compared to the clear water system. ...
Brewer's yeast as a replacement for fishmeal in the diet of tilapia (Oreochromis niloticus) was evaluated in a clear water and a biofloc environment. Triplicate groups, each of 20 juvenile tilapia (initial weight of 29 ± 3.2 g), were randomly assigned to 24 conical 500-L tanks equipped with feed waste traps. Twelve of the tanks were in a recirculating aquaculture system (RAS) with clear water, with mechanical and biological filters and on average 15% daily replacement of water. The other 12 tanks were connected to four serial 10 m3 open biogenerator tanks that were initially fed with Bacillus subtilis and nutrients in order to achieve a C:N ratio of 10, supporting bacterial growth. In this biofloc system, only evaporated water was replaced. Four iso‑nitrogenous (35%) and isoenergetic (19 MJ kg-1) diets were formulated to contain graded levels of brewer's yeast where 0%, 30%, 60% and 100% of fishmeal protein was replaced by yeast. Fish were reared for 3 months, with hand-feeding twice a day, achieving at least a fivefold increase in weight. At the end of the experiment, feed intake, protein intake, weight gain, daily weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio, survival rate and body indices of tilapia were determined. In fish reared in clear water there was a lower weight gain, daily weight gain and specific growth rate with replacement of fishmeal, but significant only in the 100% replacement group. Despite nearly identical feed and protein intake in both environments, significantly higher growth was observed in fish kept in the biofloc environment, accompanied by significantly improved feed conversion ratio and protein efficiency and reduced mortality. A significant decrease in entero-somatic and intestinal index with increasing level of dietary brewer's yeast was observed, but only in the clear water environment. No significant effects or trends were noted in any other body index data, either for yeast inclusion rates or water environments. Based on this, we concluded that brewer's yeast represents a possible high-volume substitute for fishmeal in tilapia diets, especially if the fish are reared in a high-density microbial environment, i.e. a so-called biofloc environment.
... indicated that biofloc contributed 72% of the carbon and 42% of the nitrogen in shrimp(Ray, 2012). Contrasting results have been reported, indicating that the main source of nutrients for shrimp growth is the commercial feed instead of biofloc(Cardona et al., 2015;Ray & Lotz, 2017;Suita et al., 2016). However, most of this work quantifies the contribution of the biofloc as an indivisible entity, which is well mixed with no clear variations, as it is composed of homogenous particles in suspension. ...
The aim of this study was to use the natural dietary markers (stable isotopes and fatty acids) during grow-out in a biofloc system and for the egg production of Farfantepenaeus brasiliensis shrimp. Egg production was compared for two broodstock origins: biofloc and a wild origin. To delineate the relative contribution to shrimp muscle and eggs, IsoSource software was used. The most important source that contributed to grow-out shrimp was biofloc ≥250 μm. According to the principal component analysis (PCA) applied to the fatty acid profile of food sources, the first component explains 84.4% of the variability, and the most important source of fatty acids for this component was biofloc ≥250 μm. The most important fresh food sources that contributed to egg production were Artemia biomass, polychaetes and semi-moist feed for both broodstock origins. According to a PCA analysis of the fatty acid profiles, the most important fresh foods were polychaetes and semi-moist feed. In conclusion, both isotopic signature and fatty acid profile of the food sources can be used successfully to determine the integration of carbon in the diets of shrimp.
Whiteleg shrimp is one of the most sought-after fishery commodities in the aquaculture sector due to its expensive price, good taste, and disease resistance. In response to its high demand, one of the innovations made for whiteleg shrimp culture is the Recirculating Aquaculture System (RAS). The RAS is an aquaculture technology that recycles used water with a filter to remove wastewater products. The use of RAS offers many advantages, namely reducing water turnover, good water quality, and improving the performance of whiteleg shrimp culture. In addition, RAS also reduces the likelihood of disease infection in the shrimp culture. Through this review, we would like to highlight the development of the RAS approach in whiteleg shrimp farming and its effect on cultivation performance.
Whiteleg shrimp is one of the most sought-after fishery commodities in the aquaculture sector due to its expensive price, good taste, and disease resistance. In response to its high demand, one of the innovations made for whiteleg shrimp culture is the Recirculating Aquaculture System (RAS). The RAS is an aquaculture technology that recycles used water with a filter to remove wastewater products. The use of RAS offers many advantages, namely reducing water turnover, good water quality, and improving the performance of whiteleg shrimp culture. In addition, RAS also reduces the likelihood of disease infection in the shrimp culture. Through this review, we would like to highlight the development of the RAS approach in whiteleg shrimp farming and its effect on cultivation performance.
This study aimed to evaluate three different strategies for rearing Litopenaeus vannamei in systems using biofloc or biofilters, such as heterotrophic biofloc, mixotrophic biofloc and autotrophic biofilter systems. For heterotrophic treatment, sucrose was added daily with a content of 100% feed. For mixotrophic treatment, sucrose was added daily with a content of 100% feed in the first 30 days; subsequently, the sucrose addition was reduced and stopped completely. For autotrophic treatment, a biofilter was introduced without any carbon‐source addition. Biofloc could remove ammonia efficiently, but the establishment of the nitrification process was slow, resulting in nitrite accumulation. The autotrophic system exhibited an accumulation of ammonia and nitrite in the early stages; however, it had the best water quality in the late phases. Nitrogen budget analysis showed that the proportion of nitrogen in the water of the autotrophic system was 42.51%, while in heterotrophic systems, most of the nitrogen in the aquaculture water was transferred to the biofloc (40.25%). Several differences were observed among bacterial communities when using different treatments. Bacterial community analysis indicated that the abundance of probiotics in autotrophic systems was higher, which is suitable for shrimp culture. Overall, the autotrophic system and mixotrophic system exhibited better shrimp growth performance.
Animal nutrition studies rely on traditional and advanced analytical techniques that have increased our understanding about the nutritional physiology of valuable species, leading to improved productivity, sustainability and further diversification. In the case of aquaculture nutrition, a vast amount of knowledge has accumulated in relation to different physiological responses elicited by experimental diets and feeding regimes. By measuring assimilation, inferences can be made about the specific dietary components that were digested, incorporated into tissue and used for metabolic functions. One of the most common methods applied to estimate assimilation consists of measuring stable isotope values at natural abundance levels in feeding items and consuming animals. Isotopic measurements have been of great assistance to identify nutrient sources contributing to the growth of larval and juvenile organisms. The techniques have also been useful to determine nutrient flows in several types of aquaculture systems. The present manuscript reviews the most recent applications and findings derived from studies that have used stable isotope analyses to (1) estimate nutrient assimilation in larval and juvenile organisms, (2) evaluate trophic dynamics and bioremediation potential of macroalgae and invertebrates in integrated multi-trophic aquaculture systems and (3) investigate the trophic plasticity of aquatic species. The progressively more frequent application of compound-specific isotope analysis of amino acids and fatty acids is emphasized as it has allowed exploring the physiological fate of specific organic compounds, while also assisting in the definition of nutritional requirements for aquatic species. Future nutritional applications of analytical techniques based on stable isotope measurements are addressed.
Aquaculture is a rapidly growing food production industry currently producing around half of global seafood supply. Enhancing the sustainability of intensive aquaculture is important for food security and environmental protection, as ecological impacts can arise from discharge of nutrient-rich waste streams, land use changes, and escapement of cultured organisms. Recirculating aquaculture systems (RAS) employ an integrated biofilter to process culture water, which can thereby be reused instead of discharged. This enables RAS to use less water, discharge less waste, and operate in more diverse locations compared to conventional aquaculture systems. This study evaluated low-salinity RAS production of whiteleg shrimp (Litopenaeus vannamei), a high-value species with strong international markets, through operation of a pilot system and through system modeling. A 2000-L pilot system was operated for 366 days, and shrimp production and water quality metrics were monitored to assess capabilities and limitations of the system. The operational period spanned six batches of shrimp, with all batches reared to at least 10 g and two batches reaching 20 g at harvest. Survival, growth rate, and feed efficiency improved with adjustments in system management. Though the biofilter functioned reliably for around 11 months, it failed to provide sufficient treatment during the final month of operation, indicating that sludge removal is necessary for stable long-term operation. Data generated during RAS operation was used in conjunction with literature values to construct and calibrate a model that integrates operational methods, shrimp bioenergetics, and biofilter function to generate estimates of inputs and outputs needed for stable shrimp production in the RAS. Bioenergetics describe how energy consumed by the shrimp is partitioned into growth, respiration, and wastes; through bioenergetics, the model links shrimp production quantitatively to waste production, which in turn defines biofilter capacity required. Insights gained from pilot and modeling research are valuable for development of more sustainable aquaculture, as it requires interventions that act upon complex systems.
Bacteria are ubiquitous in culture systems and may be beneficial, benign, or pathogenic to the host. It is possible to increase the abundance of beneficial bacteria in the culture water or intestines of fish and shellfish with probiotics, prebiotics or create an environment favorable to probiotics via biofloc technology (BFT). Essentially, probiotics are microorganisms that improve the health of animals. Prebiotics are nonliving ingredients that are indigestible to the host animal but are digestible by probiotics. As such, prebiotics can selectively increase probiotic abundance in the host intestine. Thus, these additives are linked. There is also a link with BFT in which an organic carbon source is added to the water, which selectively favors heterotrophic bacteria that have probiotic characteristics. Thus, the added organic carbon source can act as a prebiotic. The current trends of more intensification and use of plant-based ingredients may increase the risk of disease outbreaks and compromise immunity, respectively. However, some of these issues can be mitigated by probiotics, prebiotics, and BFT, and thus will likely increase in popularity for disease management.
In order to study the effects of carbon source addition on the bacterial community, water quality and shrimp growth in the recirculating aquaculture system of Litopenaeus vannamei, sucrose with 50% of the daily feed was added daily to the system from the middle stage of culture. The bacterial communities in biofilters, aquaculture waters and shrimp intestines were measured using an Illumina MiSeq platform. The addition of sucrose did not significantly improve the regulation of nitrogen in the water, although there was a tendency to increase shrimp production. The addition of sucrose also had little effect on the bacterial community of water and intestine, but had significant effects on the bacterial community in the biofilter. Carbon addition transformed the dominant bacterial taxa of the biofilter from the Proteobacteria dominated by Rhodobacteraceae to the Planctomycetes dominated by Planctomycetaceae. In this study, the characteristics of the bacterial community and the effects of carbon source addition in the recirculating aquaculture system of L. vannamei are presented, which provides a basis for microbial management in the recirculating aquaculture system of L. vannamei. In view of the unknown role of numerous bacterial groups, the function of the bacterial community needs further study.
This work aimed to determine the optimum stocking density of Penaeus vannamei, cultured in a photo-heterotrophic intensive circular system inlined grow-out ponds with minimal water replacement. Five intensive density levels (100, 300, 500, 700 and 900 ind m-3) were considered. The water quality measured for the 98 days grow-out period was within the adequate range for P. vannamei. TAN, nitrate and total phosphorus water quality were significantly higher (P < 0.05) at the higher density. Growth rates and survival decreased as density increased after 300 org m-3. Based on the results of this study, it was found that shrimp grows adequately in high biomass density (99.21 kg tank-1) and density of 500 ind m-3 in an intensive photo-heterotrophic system with a maximum harvest weight of 10 g.
El objetivo de esta investigación fue evaluar el efecto de un sistema con Tecnología Biofloc (TBF) y un Sistema de Recirculación Acuícola (SRA) sobre la calidad del agua y la producción de C. montezumae (acocil). El experimento tuvo una duración de 120 días. Se dio seguimiento al desarrollo de los organismos mediante observaciones y biometrías periódicas.
Indoor shrimp aquaculture systems can be used to produce fresh, never-frozen, quality shrimp near metropolitan seafood markets regardless of season and climate. However, questions still remain regarding what type of production system is best suited to maximize indoor production. In this project, two types of systems were compared: clear-water (CW) RAS and biofloc (BF) systems. Three, 1.36 m³ tanks were assigned to each of the two treatments; CW tanks had external settling chambers, two foam fractionators, and external biofilters, all operated continuously. BF tanks had settling chambers and one foam fractionator which were operated as needed to control solids accumulation. Shrimp weighing 0.42 g were stocked in all tanks at 250 m⁻³ and grown for 55 days. Ammonia and pH levels were significantly (P < 0.05) higher in the CW treatment, while nitrite, nitrate, and turbidity were all significantly higher in the BF treatment, although all parameters remained within acceptable ranges for shrimp growth. Shrimp mean harvest weight was significantly higher, biomass (kg m⁻³) was significantly greater, and FCR was significantly lower in the CW treatment; there were no significant differences in survival between treatments. Isotope levels indicated that shrimp in the BF treatment obtained a portion of the C (18-60%) and N (1-18%) in their tissues from biofloc material; however, this effect did not positively influence production in that treatment. By nearly eliminating solids from the water and using an external biofilter, substantially better water quality was maintained in the CW systems, which may have been a major contributor to the improved shrimp production in that treatment.
The aim of this study was to use preselected quality indicators for Litopenaeus vannamei post-larvae and the stable isotopes technique with δ13C and δ15N to determine the influence of bioflocs in shrimp feeding during the nursery phase, between PL1 and PL30. A control treatment (CT) with water renewal was compared to a biofloc treatment (BT) that received organic carbon fertilizations. Different types of commercial feed (Stresspak and Flake-INVE™, PL40-GUABI™), microalgae (Chaetoceros muelleri) and Artemia sp. nauplii were used as food sources. The physical and chemical parameters of water and ammonia were monitored daily, and nitrite, nitrate and alkalinity were measured weekly. Suspended solids and the microorganisms of bioflocs were characterized. At the end of the experiment, fifteen shrimps of each replicate were collected to evaluate nine larvae quality indicators. Isotopic values of 13C and 15N of food sources and shrimp tissues were collected on days 10, 20 and 30, and a Bayesian model of isotopic mixture measured the contributions of these sources to the shrimp biomass. Salinity, alkalinity and nitrite differed significantly between the treatments but were appropriate for post-larvae production. The larvae quality conditions in the CT treatment were ranked as “good,” whereas the BT conditions were considered “excellent” according to the analysis of larval quality parameters. The stable isotopes analysis showed that the PL40 GUABI™ feed was the most important food source throughout the experimental period in the CT. In the BT (10th and 20th days), the bioflocs and commercial feeds (Flake-INVE™, PL40-GUABI™) did not present significant variations in their contribution ratios; however, on the 30th day, the contribution of the PL40-GUABI™ feed was higher when compared to bioflocs. In general, the commercial feed played a more important role as a food source for Litopenaeus
vannamei larvae during the nursery phase, although the consumption of bioflocs led to a better larvae quality.
Superintensive shrimp culture in zero-exchange, biofloc-dominated production systems is more biosecure and sustainable than traditional shrimp farming practices. However, successful application of this technology depends upon optimizing dietary formulations, controlling Vibrio outbreaks, and managing accumulative changes in water quality and composition. A 49-d study investigated the effect of two commercial feeds of differing protein content and an indoor limited-exchange, biofloc-dominated culture environment on Litopenaeus vannamei performance and tissue composition, water quality and ionic composition, and Vibrio dynamics. Juveniles (5.3g) were stocked at 457/m3 into four 40m3 shallow raceways containing biofloc-dominated water and fed one of two commercial feeds with differing protein content, 35 or 40%. Shrimp performance, Vibrio populations, and changes in shrimp and culture water composition were monitored. There were no significant differences (P>0.05) in shrimp performance (survival, weight, growth, specific growth rate, total biomass, yield, feed conversion ratio, and protein efficiency ratio) or proximate composition between feed types. The 40% protein feed resulted in higher culture water nitrate and phosphate concentrations, alkalinity consumption and bicarbonate use, and higher phytoplankton density. The presence of Vibrio, specifically Vibrio parahaemolyticus, reduced shrimp survival. This survival decrease corresponded with increased culture water Vibrio concentrations. Culture water K+ and Mg2+ increased significantly (P<0.05), and Sr2+, Br-, and Cl- decreased significantly (P<0.05) over time. While Cu2+ and Zn2+ did increase in shrimp tissue, no heavy metals accumulated to problematic levels in culture water or shrimp tissue. These results demonstrate the importance of monitoring Vibrio populations and ionic composition in limited-exchange shrimp culture systems.
Bioflocs Oxygen dynamics Resuspension, mixing, and sludge management Nitrogenous waste products Temperature Feeds and feeding Economics Sustainability Outlook and research needs Acknowledgment References
The present study evaluates the biofloc technology (BFT) in light-limited tank culture of Nile tilapia (Oreochromis niloticus). Two biofloc treatments and one control were managed in 250 l indoor tanks: BFT fed a diet of 35% crude protein (CP), BFT fed a diet of 24% CP, and clean water control without biofloc with 35% CP. BFT tanks were aerated and agitated using a dome diffuser. Three kg of Nile tilapia were stocked in each tank. Feed was applied at 1.5% of the total fish biomass daily in each tank. Wheat flour was added in BFT tanks to maintain an optimum C:N ratio for heterotrophic production. The total suspended solid (TSS) level was maintained at around 500 mg l−1 in BFT tanks.The nutritional quality of biofloc was appropriate for tilapias. Fish survival was 100%. Net fish production was 45% higher in the BFT tanks than in the control tanks confirming the utilization of biofloc by fish as food. There was no difference in fish growth/production between 35% and 24% CP fed tanks under BFT. Welfare indicators in terms of fin condition, gill histology, proximate composition, blood haematocrit and plasma cortisol levels were compared and no significant differences between BFT and control tanks were recorded indicating no increased fish stress due to the presence of biofloc. However, overall fish growth and production was poor in terms of commercial feasibility. A modified system design that would allow enhanced feed and biofloc utilization is proposed.
Zero water exchange, super-intensive culture of shrimp in enclosed raceway type systems can be considered environmentally friendly in that containment of water within the system prevents potential spread of disease between the wild populations and cultured animals and avoids nutrient rich waste from polluting coastal waters. However, as a relatively new strategy for shrimp production, there is much still to be learned about the potential biological and economic benefits of producing shrimp in suspended microbial floc based systems. Understanding shrimp feeding behavior and quantification of shrimp feed consumption provides valuable information for culturists to improve feed management, one of the keys to economic viability. The objective of this study was to evaluate the nutritional contribution of varying levels of microalgae/bacterial floc on survival, growth, food consumption, and FCR of Litopenaeus vannamei juveniles fed diets with different protein levels in replicated experimental microcosm tanks. The 20 day experiment evaluated 9 treatments, three water types fed three different protein diets. Water was recirculated within a sump and consisted of either clear, UV filtered water, water containing microbial floc from an adjacent zero exchange super-intensive raceway production unit, or a 50:50 mix of clear water and raceway water. Diet treatments were either no food, 25% or 35% protein content. Treatments were randomly assigned to 50 L, mesh covered plastic bins receiving each water type. Each treatment consisted of five replicates, each containing 44 shrimp, with a mean stocking weight of 1.82 ± 0.71 g for a final density of 300 per m2. Shrimp in each treatment (except the no feed treatment) were fed 3 times daily via a specially designed feed tray. Food consumption and FCR were calculated based on weight gain, survival, total consumed feed, feed loss through leaching, and initial feed moisture content. Results were analyzed by two-way analysis of variance (ANOVA) and differences between the means analyzed by Tukey's test (α = 0.05). Survival in the fed treatments was greater than 98% in all treatments (P > 0.05). Survival in the non-fed treatments was significantly higher in the raceway water treatments than in the clear water treatment (P < 0.05). Final weight, weight gain, final biomass, food consumption and FCR were significantly higher (P < 0.05) in all treatments fed with 35% protein feed. This result suggests a positive relationship between the growth parameters and the protein content of the feeds in this system, and confirms the benefit of natural productivity for production of L. vannamei.
In intensive aquaculture systems, ammonia–nitrogen buildup from the metabolism of feed is usually the second limiting factor to increase production levels after dissolved oxygen. The three nitrogen conversion pathways traditionally used for the removal of ammonia–nitrogen in aquaculture systems are photoautotrophic removal by algae, autotrophic bacterial conversion of ammonia–nitrogen to nitrate–nitrogen, and heterotrophic bacterial conversion of ammonia–nitrogen directly to microbial biomass. Traditionally, pond aquaculture has used photoautotrophic algae based systems to control inorganic nitrogen buildup. Currently, the primary strategy in intensive recirculating production systems for controlling ammonia–nitrogen is using large fixed-cell bioreactors. This option utilizes chemosynthetic autotrophic bacteria, Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB), for the nitrification of ammonia–nitrogen to nitrite–nitrogen and finally to nitrate–nitrogen. In the past several years, zero-exchange management systems have been developed that are based on heterotrophic bacteria and have been promoted for the intensive production of marine shrimp. In this third pathway, heterotrophic bacterial growth is stimulated through the addition of organic carbonaceous substrate. At high carbon to nitrogen (C/N) feed ratios, heterotrophic bacteria will assimilate ammonia–nitrogen directly into cellular protein. This paper reviews these three ammonia removal pathways, develops a set of stoichiometric balanced relationships using half-reaction relationships, and discusses their impact on water quality. In addition, microbial growth fundamentals are used to characterize production of volatile and total suspended solids for autotrophic and heterotrophic systems.
Controlling the inorganic nitrogen by manipulating the carbon/nitrogen ratios is a potential control method for aquaculture systems. This approach seems to be a practical and inexpensive means of reducing the accumulation of inorganic nitrogen in the pond. Nitrogen control is induced by feeding bacteria with carbohydrates, and through the subsequent uptake of nitrogen from the water, by the synthesis of microbial proteins. The relationship among the addition of carbohydrates, the reduction of ammonium and the production of microbial proteins depends on the microbial conversion coefficient, the C/N ratio in the microbial biomass, and the carbon contents of the added material. The addition of carbonaceous substrate was found to reduce inorganic nitrogen in shrimp experimental tanks and in tilapia commercial-scale ponds. It was found in tilapia ponds that the produced microbial proteins are taken up by the fish. Thus, part of the feed protein is replaced and feeding costs are reduced. The addition of carbohydrates, or the equivalent reduction of proteins in the feed, can be quantitatively calculated and optimised, as shown here. Approximate parameters were used in this work. Additional research in this field should be directed at gathering the precise data needed for the exact planning of feed composition.
The dual objective of sustainable aquaculture, i.e., to produce food while sustaining natural resources is achieved only when production systems with a minimum ecological impact are used. Recirculating aquaculture systems (RASs) provide opportunities to reduce water usage and to improve waste management and nutrient recycling. RAS makes intensive fish production compatible with environmental sustainability. This review aims to summarize the most recent developments within RAS that have contributed to the environmental sustainability of the European aquaculture sector. The review first shows the ongoing expansion of RAS production by species and country in Europe. Life cycle analysis showed that feed, fish production and waste and energy are the principal components explaining the ecological impact of RAS. Ongoing developments in RAS show two trends focusing on: (1) technical improvements within the recirculation loop and (2) recycling of nutrients through integrated farming. Both trends contributed to improvements in the environmental sustainability of RAS. Developments within the recirculation loop that are reviewed are the introduction of denitrification reactors, sludge thickening technologies and the use of ozone. New approached towards integrated systems include the incorporation of wetlands and algal controlled systems in RAS. Finally, the review identifies the key research priorities that will contribute to the future reduction of the ecological impact of RAS. Possible future breakthroughs in the fields of waste production and removal might further enhance the sustainabilty of fish production in RAS. (C) 2010 Elsevier B.V. All rights reserved.
For decades, plant ecologists have used naturally occurring stable isotope ratios to disentangle ecological and physiological processes. The methodology can also become a very powerful tool in animal ecology. However, the application of the technique relies on assumptions that are not widely recognized and that have been rarely tested. The purpose of this communication is to identify these assumptions, to characterize the conditions in which they are not met, and to suggest the laboratory experiments that are needed to validate them. The ease with which isotopic data can be gathered and the growing popularity of the method are generating a large amount of data on the isotopic ecology of animals. The proper interpretation of these data demands that we identify the assumptions on which these inferences are based, and that we conduct comparative laboratory experiments to assess their validity.
In light of the increasing demand for fish, the challenge for planners now is to accelerate aquaculture development and to plan for new production, making urban areas not only centres of marketing and distribution, but also of production, particularly using urban wastewater. This book includes papers from authors in the USA, Europe and Asia that review these developing issues from the perspective of both developed and developing countries. Urban aquaculture education is also considered. The book is intended for those researching in aquaculture, water resources, urban planning and geography. It has 19 chapters and a subject index.
The study of stable isotope ratio variations at the natural abundance level for the light elements became an important aspect of geology and geochemistry almost as soon as the chemical basis of isotope effects was known (Epstein 1959). The temperature dependence of the equilibrium isotope effect and the empirical correlations for petroleum, natural gas, and source rock stable carbon isotope ratios provided strong stimuli for geochemical investigations (Degens 1969). Although significant variations in stable carbon isotope ratios of plants and animals were noted by several investigators, their ecological implications were not immediately recognized. Nier and Gulbransen (1939) reported the 13C depletion of lipids relative to whole cells, yet only now are variations at the level of individual molecule type being utilized.
Minimal exchange superintensive culture systems have many advantages over traditional aquaculture practices including high crop density, year-round production, a small land-footprint, inland production, and reduced environmental impacts. Such culture units are completely reliant on a dense, suspended microbial community to mineralize and cycle nutrients and to provide supplemental nutritional benefits to shrimp. A portion of the microbial community is contained in biofloc particles which are composed of shrimp molts, feces, uneaten feed, algae, and a rich diversity of heterotrophic and chemo-autotrophic bacteria, cyanobacteria, micro- and macroinvertebrates that colonize them. All play key roles in system dynamics. However biofloc systems may also foster outbreaks of noxious dinoflagellates such as Pfiesteria sp. or harmful cyanobacteria. Although species populations are dynamic to a great degree, specific management regimes can be implemented to develop and maintain the most advantageous microbial communities in order to optimize shrimp production.
We have recently evaluated several relatively simple management techniques that can be used to alter microbial dynamics, thereby changing system performance. The amount and quality of light penetrating the system can influence community structure. Shrimp can be grown in systems with virtually no light input, thereby eliminating photoautotrophic organisms. A more heterotrophic system will demand greater oxygen input during daylight hours, but will reduce risks associated with harmful algae. By eliminating reliance on sunlight, heterotrophic systems can be housed in insulated buildings rather than greenhouses, leading to dramatic reductions in energy costs during cooler months. Conversely, managing systems to increase photoautotrophy is attractive both because oxygen delivery to the system can be reduced during daylight hours and because algal dominated systems appear to provide exceptional supplemental nutrition for shrimp. In a recent study we found that shrimp production in a primarily photoautotrophic raceway was 17% greater and FCR 18% lower, than in a totally heterotrophic raceway.
An effective method of encouraging photoautotrophy is to increase light availability by removing suspended solids from the water column. Solids management will also reduce oxygen demand within the biofloc system, up to 86% of which can be attributed to the microbial community. We have used cost effective, low energy settling chambers to crop suspended solids from superintensive biofloc systems and have achieved increases in shrimp production of 41% over uncropped systems. Fertilization, seeding, and water reuse should be used to develop a strong nitrifying community prior to stocking. Once established, water quality is remarkably stable in biofloc systems; however, dextrose additions can effectively guide a system through early ammonia and nitrite spikes. Careful monitoring coupled with educated management will lead to optimal microbial conditions and significantly improve shrimp production.
Suspended organic particles produced in an intensive shrimp pond with an earthen substratum can significantly enhance shrimp growth. However, the role of the substratum in eliciting this effect is unknown. It was hypothesized that clay particles, derived from the substratum, are important in transferring suspended organic particles to the pond bottom where they become available to shrimp. To test this hypothesis, it was determined if suspended particles, produced in a plastic-lined pond without an earthen substratum, can improve shrimp growth. Juvenile Penaeus vannamei were reared in 120-liter microcosm tanks at a density of 40 shrimp/m2. A 2 × 2 factorial experiment was conducted in which triplicate tanks received flow-through water from either a 337-m2, plastic-lined pond used for intensive shrimp culture or from a seawater well. In addition, shrimp were fed either a commercial diet ad libitum or were unfed. After 14 days, there was a highly significant water source effect on shrimp growth (P < 0.001). Growth rates of shrimp in pond water + feed (1.20 g/wk) were 62% greater than growth rates of shrimp in well water + feed (0.74 g/wk). Unfed shrimp in pond water grew 0.23 g/wk, whereas unfed shrimp in well water lost weight (−0.045 g/wk). These results indicate that algal-clay flocculation is not an important mechanism in eliciting the growth-enhancing effect of shrimp pond water and that particles suspended in pond water may not need to interact with the substratum in order to contribute to shrimp growth.
Chronic toxicity of nitrate (NO3−) has not been well documented in the culture of penaeid shrimp. To interpret this problem, lab-scale research was conducted in recirculating aquaculture systems (RAS) to determine the long-term impacts of nitrate on shrimp growth, survival, total mass of shrimp per system (shrimp biomass), antennae length, and tissue pathology. The first experiment, Trial (A), was performed over a six week period at 11 (ppt) salinity and consisted of a Control A (35ppm nitrate-N), Treatment A1 (220ppm nitrate-N), Treatment A2 (435ppm nitrate-N), and Treatment A3 (910ppm nitrate-N). No differences were observed between control A and treatment A1 in terms of shrimp survival, growth, shrimp biomass, and antennae length. Treatment A2 exhibited no significant differences compared to Control A in terms of survival and growth, but did exhibit significant negative impacts (P
The objective of this study was to evaluate the effects and interactions of stocking density and light level on the growth and survival of Litopenaeus vannamei in zero-exchange mixed biofloc systems. The necessity of light and its effects on stocking density could provide essential information for efficient system design in temperate regions. Twelve, 3800-L conical-bottom tanks housed in a greenhouse were filled with dechlorinated city water, adjusted to 25 ppt salinity, inoculated with mixed biofloc communities, and randomly assigned to one of four different treatment combinations. The study was a 2 × 2 factorial arrangement with main effects being stocking density (182 shrimp/m2 [low density; LD] vs. 364 shrimp/m2 [high density; HD]) and light (natural light [NL] vs. low level artificial [LL]) with three replicate tanks per treatment. Tanks in the NL treatment received ambient greenhouse light. For the LL treatment black plastic was used to block NL and a single 60-W incandescent bulb was hung over each low-light tank and operated on a 12:12 h schedule. Juvenile L. vannamei (0.40 ± 0.28 g) were stocked in rotation into each tank and fed a 35% protein diet twice daily at an initial 10% of body weight, gradually decreasing to 3% of body weight prior to harvest. After 12 wk, there was a statistically significant (P≤ 0.05) interaction between density and light level; therefore, data were analyzed in terms of treatment combinations. Average harvest weight of shrimp was significantly higher (P≤ 0.05) in the LD/NL treatment (14.5 g) than in the HD/LL treatment (12.4 g), but neither was significantly different from HD/NL (13.6 g) and LD/LL (13.4 g). Survival of shrimp was significantly lower (P≤ 0.05) in the HD/LL treatment (61.8%) than in the LD/NL (89.8%) and LD/LL (89.0%) treatments. Survival in the HD/NL treatment (82.7%) was intermediate and not significantly different (P > 0.05) from the other treatments. Harvest yield was significantly greater (P≤ 0.05) in the HD/NL treatment (4.1 kg/m2) than in the LD/NL, LD/LL, and HD/LL treatments (2.4, 2.2, and 2.8 kg/m2, respectively), which were not significantly different (P > 0.05) from each other. These data indicate that a combination of high stocking rate with high light levels or NL may be needed to achieve maximum production; however, relatively low levels of artificial light may be suitable at low stocking densities. Further research should investigate the type and amount of light needed to achieve optimal results.
Postlarvae ofPenaeus vannameiwere fed various diets in order to examine the importance of detritus and other possible prey items in supporting postlarval growth. Stable isotopes (C and N) were used to determine the carbon and nitrogen source of the prey in the various diets. The zooplankton diet contained mostly copepods. The subtidal detritus treatment consisted mostly of plant material whereas the diets from both intertidal sites contained a mixture of plant detritus and associated meiofauna. Postlarvae reared on zooplankton and detritus plus meiofauna diets more than tripled their weight during a 6-day period. In contrast, postlarvae fed the detritus diet barely doubled their weight. Based on isotopic composition, postlarvae appear to obtain their carbon and nitrogen from various food sources. Postlarvae were enriched by 0·4‰ in13C and 2·7‰ in15N relative to the zooplankton diet, which is consistent with isotopic fractionation between successive trophic levels. In turn, the isotopic signal of the zooplankton was consistent with phytoplankton being the initial source of organic matter. In contrast, mean δ13C values of the shrimp fed detritus plus meiofauna were significantly different from their respective diets. Isotopic ratios of the postlarvae fed the mixed diet from Chomes were two trophic levels above benthic algae suggesting that the shrimp preyed on organisms that derived their carbon and nitrogen from benthic algae and/or phytoplankton.
A 10-wk experiment was conducted to determine whether shrimp pond water has a sparing effect on vitamins, trace minerals, and protein levels in diets fed to juvenile Pacific white shrimp, Litopenaeus vannamei. Twenty-four 52-L aquaria were stocked with 0.7-g shrimp at a density of 24 shrimp/aquaria (100 shrimp/m2 equivalent). Shrimp were exposed to flow-through seawater from one of two sources: clear well water from a seawater aquifer or organically rich water from a pond used for intensive shrimp culture. In addition, four diets were evaluated in each of the two water sources (three replicates/treatment), including: 1) a 35%-protein diet with vitamin and trace mineral premixes, 2) the same 35%-protein diet minus the vitamin premix, 3) the 35%-protein diet minus the trace mineral premix, and 4) a 25%-protein diet with vitamin and trace mineral premixes. Shrimp grown in well water without vitamins in their diet had a significantly lower (P
Isotopes are forms of an element that differ in the number of neutrons. Isotopes function as natural dyes or colors, generally tracking the circulation of elements. Isotopes trace ecological connections at many levels, from individual microbes to whole landscapes. Isotope colors mix when source materials combine, and in a cyclic process that ecologists can appreciate, the process of isotope fractionation takes the mixed material and regenerates the sources by splitting or fractionating the mixtures. Elements and their isotopes circulate in the biosphere at large, but also in all smaller ecological plant, animal, or soil systems. Chapter 3 reviews this circulation for each of the HCNOS elements, then gives four short reviews that may stimulate you to think about how you could use isotopes in your own ecological research.
The uptake and assimilation of nitrogen and carbon by shrimp were measured in 1200 L mesocosms using stable isotope enrichments. Labels were added via 15N-, 13C-glycine and amino acid mixtures in feeds or as 15NH4+ to pond water. Label was incorporated into shrimp via algal growth indicating that up to 31% of nitrogen requirements were derived from pond ecosystem dynamics. This value is low in comparison with other shrimp aquaculture isotopic tracer studies but is probably due to differences in shrimp-rearing conditions. Direct incorporation of the enriched feed label was low in shrimp muscle tissue (3.3% for 13C-glycine, 5.9% for 15N-glycine and 7.8% for 15N-amino acid mixture). Mass balance calculations indicate the remaining shrimp biomass was derived from feed, but loss of label into solution during feeding led to underestimation based on tracers. Incorporation of isotopic labels into feed as large molecular weight proteinaceous or microencapsulated/fat-coated compounds is recommended to prevent dissolution and loss.
Crude enzyme extracts were obtained from the digestive glands of Pacific white shrimp, Litopenaeus vannamei (Boone), reared in oligotrophic well water and eutrophic shrimp pond water to compare digestive enzyme activity between the two groups. Specific activities of serine protease, collagenase, amylase, cellulase, lipase and acid phosphatase were significantly higher (P < 0.01) in pond water-reared shrimp (PW shrimp) than in well water reared-shrimp (WW shrimp). For most enzymes assayed, specific activity was more than two times higher in PW shrimp, and cellulase activity was over six times higher. In contrast, chitinase activity was significantly higher (P < 0.001) in WW shrimp. Higher specific activity of most digestive enzymes in PW shrimp was probably due to natural productivity in the pond water that served as a source of organic substrates, and this increased activity may contribute to the growth-enhancing effect of shrimp pond water.
This study showed that particulate (i.e., physical) toxicity was responsible for rainbow trout deaths in bioassays with two separate solid wastes. This conclusion was based on: (1) fish necropsies which indicated physical damage to gills but no evidence of chemical damage to liver or kidney, (2) chemical analyses which indicated that levels of Priority Pollutants and other target compounds were too low to cause the observed toxicity, (3) structural and chemical analyses of the waste particles which showed that these consisted of inert materials, and (4) the use of centrifugation techniques to remove most of the suspended particulate material in bioassay tanks resulting in an elimination of most of the toxicity. The particles associated with the lethal effects were approximately 5 to 10 m in size. Regulatory testing of solid wastes must distinguish physical and chemical toxicity since disposal options can vary depending on the mode of toxicity. For instance, chemical toxicity raises concern regarding leaching through soils into groundwater, whereas if physical particles are responsible for toxicity, such leaching is not of concern.
High-intensity, zero-exchange shrimp ponds contain a high density of flocculated particles, rich in bacteria and phytoplankton, compared with flow-through systems. The flocculated particles provide a potential food source for shrimp. Short-term tank experiments were conducted to determine the retention of nitrogen (N) from natural biota, dominated by flocculated particles, in white shrimp (Litopenaeus vannamei) at a high-intensity, zero-exchange shrimp farm in Central America (Belize Aquaculture (BAL)). There were two treatments: ‘floc’ and ‘floc+20%’ (3×1000-l replicate tanks each) based on two densities of flocculated particles. The floc density in the ‘floc’ treatment was typical of shrimp growout ponds at BAL, whereas the ‘floc+20%’ treatment had a 20% higher density of flocculated particles. Three consecutive experiments were conducted with 1, 5 and 9 g shrimp, respectively. At the start of the experiment, 15N-ammonium was added to the tanks and assimilated by the natural biota. Shrimp were maintained in these tanks for 48 h after the 15N-nitrogen enrichment. After this time, shrimp were found to be enriched with 15N-nitrogen. It was calculated that between 1% and 3% of the particulate nitrogen in the tanks, principally from the flocculated particles, was retained by the shrimp. The proportion of estimated daily nitrogen retention of the shrimp contributed by the natural biota was calculated to be 18% to 29% for 1 to 9 g animals in the floc treatment. There was a tendency for greater retention in the floc+20% treatments, but this trend was not consistent. This study suggests that natural biota, which in this system was largely flocculated particles, can contribute substantially to the nutrition of L. vannamei. There are, therefore, benefits for shrimp in the promotion of flocculated particles in L. vannamei ponds. Whether this translates into improvements in shrimp growth and production efficiency remains to be established.
Tolerance of whiteleg shrimp Litopenaeus vannamei exposed to different temperatures (14.5, 21.5, 24.8, 27.8, 30.8, and 35.0 °C), salinities (9, 15, 26, 35, and 40‰), pH (3.3, 6.5, 7.7, 8.1, and 9.2), and light intensities (strong 2100 lx and weak 60 lx) at various body weights (3.0, 3.7, 4.3, 5.7, 7.8, 9.0, 9.5, 10.7, 11.9, and 13.3 g) and feeding conditions (fed for 3 h, fasted for 12 h, and fasted for 48 h) to hypoxic stress was measured. Regression models for the effects of body weight, temperature, salinity, and pH on lethal dissolved oxygen (DO) levels were derived from the data. Body weight, temperature, salinity, and pH had significant effects on lethal DO levels (P < 0.01). The estimated body weight (BW), temperature (T), salinity (S), and pH (pH) for minimum lethal DO levels (LDOL) were 9.17 g, 22 °C, 16.6‰, and 7.56 (LDOL = 0.0076 BW2 − 0.1394 BW + 1.1471, r2 = 0.94; LDOL = 2.4291 × 10− 5 T3 − 0.0008 T2 + 0.6095, r2 = 0.66; LDOL = − 7.8212 × 10− 5 S3 + 0.0058S2 − 0.1280 S + 1.2424, r2 = 0.98; LDOL = 0.1487 pH2 − 2.2488 pH + 8.8806, r2 = 0.99), respectively. The lethal DO levels of the shrimps exposed to strong light (2100 lx) were 75.1% of those exposed to weak light (60 lx), but there was no significant difference (P > 0.05) between the two light intensities. The lethal DO levels of the shrimps fed for 3 h were 80.6% of those fasted for 48 h (P<0.01), but no significant difference (P > 0.05) was found between those fed for 3 h and fasted for 12 h. These results indicated that L. vannamei cultured at optimum conditions has the best ability to withstand hypoxia. Therefore, it is suggested that water temperature be maintained at 22 °C, salinity 16.6‰, pH 7.56, and strong light conditions for water management practice in L. vannamei culture when hypoxia happened.
Trials were conducted in laboratory to investigate the growth performance, body composition, respiration and ammonia-N tolerance of the white shrimp, Litopenaeus vannamei, at 3.0, 17.0 and 32.0‰, respectively. In the growth trial, 40 juvenile shrimps were stocked into each tank with four replicates at each salinity, and were fed with a commercial diet for 50 d. Shrimp weight gain at 17.0‰ was the highest, and significantly higher than that of shrimps at 3.0‰. Shrimp survival rate at 3.0‰ was significantly lower than that of other two groups. However, hepatosomatic index and condition factor were not significantly affected by the ambient salinity. Shrimp body protein and ash content were not affected significantly by salinity, while body moisture increased at high salinity, and crude lipid in shrimps was lowest at 32.0‰. After being exposed to the above three salinities for 30 d prior to the test, shrimp oxygen consumption and respiratory quotient of the shrimps at 3.0‰ were significantly higher than those of shrimps at medium and high salinities, while salinity did not significantly affect CO2 production. When juvenile L. vannamei were exposed to seven ammonia-N concentrations (0, 4.00, 6.67, 9.33, 12.00, 14.67, and 17.33 mg l− 1) at the three above salinities to which shrimps had been separately acclimated for 10 d at pH 8.30 and 29 ± 0.5 °C, shrimps at 3‰ were the most susceptible to ambient ammonia-N, and the 96 h LC50 with 95% confidence limit to ambient ammonia-N was 9.33 (8.39–10.37) mg l− 1. This study suggests that L. vannamei could adapt to a wide range of salinity, but the animals would be more susceptible to ammonia toxicity and spend more energy to compensate the cost for osmoregulation at low salinity.
Litopenaeus vannamei juveniles (total length 56±9.6 mm) were exposed to different concentrations of nitrite-N (nitrite as nitrogen), using a static renewal method at salinity levels of 15‰, 25‰ and 35‰ (g/kg) pH 8.02 and 18 °C. The 24-, 48-, 72-, 96- and 144-h LC50 value of nitrite-N on L. vannamei juveniles were 187.9, 142.2, 92.5, 76.5, 61.1 mg/l at 15‰; 274,1, 244.0, 224.8, 178.3, 152.4 mg/l at 25‰; 521.2, 423.9, 375.0, 321.7, 257.2 mg/l at 35‰, respectively. As the salinity decreased from 35‰ to 15‰, susceptibility of nitrite-N increased by 277%, 298%, 405% and 421% after 24-, 48-, 72-, 96- and 144-h exposure, respectively. The “safe level” for rearing L. vannamei juveniles was estimated to be 6.1, 15.2, 25.7 mg/l for nitrite-N in 15‰, 25‰ and 35‰, respectively. The relationship between LC50 of nitrite-N (mg/l), salinity (S) and exposure time (T) is as follows: LC50=123.0182+0.3657S−0.6072T (R2=0.9847).
In minimal-exchange, superintensive culture systems, the flocculated (biofloc) particles that accumulate may provide benefits for cultured shrimp; however, excessive particle accumulation can hinder shrimp performance. Also, the shrimp aquaculture industry is reliant on marine fish-based feeds. Using these products can lead to exploitation of marine resources, the introduction of contaminants to cultured shrimp, and unstable production costs. This study examined the use of simple, side-stream settling chambers as a means of controlling the abundance of particles in the water column and demonstrated the effects on water quality and shrimp production. The study also compared water quality and shrimp production parameters between a commercial, fish-based diet and a diet formulated almost entirely from vegetarian components, with expelled soybean meal as its principle protein source. The fish-based diet and the plant-based diet each contained 35.7% and 36.4% crude protein and 11.0% and 10.8% total lipid, respectively. The experiment was conducted in 3.35 m diameter, outdoor tanks, shrimp were stocked at 460 m− 3 and grown for 12 weeks. By the end of the experiment, settling chambers had removed 59% of suspended solids, decreased turbidity by 57%, reduced nitrate–nitrogen concentration by 60%, reduced phosphate concentration by 61%, and caused a 33% increase in alkalinity, all highly significant effects. Settling chambers also contributed to significantly improved shrimp feed conversion ratio, biomass, growth rate, and final weight (P = 0.002, 0.006, < 0.001, and 0.001, respectively). Final shrimp biomass (kg m− 3) was 41% greater in treatments with solids management than those without. Shrimp survival was not statistically different with or without settling chambers. Water quality parameters were not statistically different between the two diet types, except phosphate concentration which, by the end of the experiment, was 34% lower in the tanks receiving the plant-based diet. Shrimp production parameters were not statistically different between the two diets. The study showed that controlling the concentration of particles in superintensive shrimp culture systems can significantly improve water quality and shrimp production. Also, an environmentally friendly and potentially economical plant-based diet can produce results comparable to a fish-based feed in superintensive shrimp culture systems.
Profitability of recirculating systems depends in part on the ability to manage nutrient wastes. Nitrogenous wastes in these systems can be eliminated through nitrifying and denitrifying biofilters. While nitrifying filters are incorporated in most recirculating systems according to well-established protocols, denitrifying filters are still under development. By means of denitrification, oxidized inorganic nitrogen compounds, such as nitrite and nitrate are reduced to elemental nitrogen (N2). The process is conducted by facultative anaerobic microorganisms with electron donors derived from either organic (heterotrophic denitrification) or inorganic sources (autotrophic denitrification). In recirculating systems and traditional wastewater treatment plants, heterotrophic denitrification often is applied using external electron and carbon donors (e.g. carbohydrates, organic alcohols) or endogenous organic donors originating from the waste. In addition to nitrate removal, denitrifying organisms are associated with other processes relevant to water quality control in aquaculture systems. Denitrification raises the alkalinity and, hence, replenishes some of the inorganic carbon lost through nitrification. Organic carbon discharge from recirculating systems is reduced when endogenous carbon sources originating from the fish waste are used to fuel denitrification. In addition to the carbon cycle, denitrifiers also are associated with sulfur and phosphorus cycles in recirculating systems. Orthophosphate uptake by some denitrifiers takes place in excess of their metabolic requirements and may result in a considerable reduction of orthophosphate from the culture water. Finally, autotrophic denitrifiers may prevent the accumulation of toxic sulfide resulting from sulfate reduction in marine recirculating systems. Information on nitrate removal in recirculating systems is limited to studies with small-scale experimental systems. Packed bed reactors supplemented with external carbon sources are used most widely for nitrate removal in these systems. Although studies on the application of denitrification in freshwater and marine recirculating systems were initiated some thirty years ago, a unifying concept for the design and operation of denitrifying biofilters in recirculating systems is lacking.
For decades, plant ecologists have used naturally occurring stable isotope ratios to disentangle ecological and physiological processes. The methodology can also become a very powerful tool in animal ecology. However, the application of the technique relies on assumptions that are not widely recognized and that have been rarely tested. The purpose of this communication is to identify these assumptions, to characterize the conditions in which they are not met, and to suggest the laboratory experiments that are needed to validate them. The ease with which isotopic data can be gathered and the growing popularity of the method are generating a large amount of data on the isotopic ecology of animals. The proper interpretation of these data demands that we identify the assumptions on which these inferences are based, and that we conduct comparative laboratory experiments to assess their validity.
The expansion of the aquaculture production is restricted due to the pressure it causes on the environment by the discharge of waste products in the water bodies and by its dependence on fish oil and fishmeal. Aquaculture using bio-flocs technology (BFT) offers a solution to both problems. It combines the removal of nutrients from the water with the production of microbial biomass, which can in situ be used by the culture species as additional food source. Understanding the basics of bio-flocculation is essential for optimal practice. Cells in the flocs can profit from advective flow and as a result, exhibit faster substrate uptake than the planktonic cells. The latter mechanisms appear to be valid for low to moderate mixing intensities as those occurring in most aquaculture systems (0.1–10 W m− 3). Yet, other factors such as dissolved oxygen concentration, choice of organic carbon source and organic loading rate also influence the floc growth. These are all strongly interrelated. It is generally assumed that both ionic binding in accordance with the DLVO theory and Velcro-like molecular binding by means of cellular produced extracellular extensions are playing a role in the aggregation process. Other aggregation factors, such as changing the cell surface charge by extracellular polymers or quorum sensing are also at hand. Physicochemical measurements such as the level of protein, poly-β-hydroxybutyrate and fatty acids can be used to characterize microbial flocs. Molecular methods such as FISH, (real-time) PCR and DGGE allow detecting specific species, evaluating the maturity and stability of the cooperative microbial community and quantifying specific functional genes. Finally, from the practical point of view for aquaculture, it is of interest to have microbial bio-flocs that have a high added value and thus are rich in nutrients. In this respect, the strategy to have a predominance of bacteria which can easily be digested by the aquaculture animals or which contain energy rich storage products such as the poly-β-hydroxybutyrate, appears to be of particular interest.
Nitrite in environmental water samples is reduced at room temperature to nitric oxide in acidic medium containing vanadium (III). Nitrate is also rapidly reduced after heating to 80-90 degrees C. Nitric oxide is removed from the reaction solution by scrubbing with helium carrier gas and is detected by means of a chemiluminescence NOx analyzer. Nanogram detection limits are obtained. The method has the advantage of not requiring highly acidic solutions for nitrate reduction and has been applied to the analysis of a variety of environmental waters, sediment, plant materials, and human urine and blood serum.
Litopenaeus vannamei juveniles (total length 22+/-2.4 mm) were exposed to different concentrations of ammonia-N (un-ionized plus ionized ammonia as nitrogen), using the static renewal method at different salinity levels of 15 per thousand, 25 per thousand and 35 per thousand at pH 8.05 and 23 degrees C. The 24, 48, 72, 96 h LC50 values of ammonia-N on L. vannamei juveniles were 59.72, 40.58, 32.15, 24.39 mg l(-1) at 15 per thousand; 66.38, 48.83, 43.17, 35.4 mg l(-1) at 25 per thousand; 68.75, 53.84, 44.93, 39.54 mg l(-1) at 35 per thousand, respectively. The 24, 48, 72, 96 h LC50 values of NH(3)-N (un-ionized ammonia as nitrogen) were 2.95, 2.00, 1.59, 1.20 mg l(-1) at 15 per thousand; 2.93, 2.16, 1.91, 1.57 mg l(-1) at 25 per thousand; 2.78, 2.18, 1.82, 1.60 mg l(-1) at 35 per thousand, respectively. As the salinity decreased from 35 per thousand to 15 per thousand, susceptibility of ammonia-N increased by 115%, 132%, 140% and 162% after 24, 48, 72 and 96 h exposure, respectively. The "safety level" for rearing L. vannamei juveniles was estimated to be 2.44, 3.55, 3.95 mg l(-1) for ammonia-N and 0.12, 0.16, 0.16 mg l(-1) for NH(3)-N in 15 per thousand, 25 per thousand and 35 per thousand, respectively.
Biofloc production systems for aquaculture. Southern Regional
- J A Hargreaves
Hargreaves, J.A., 2013. Biofloc production systems for aquaculture. Southern
Regional. Aquaculture Center Publication 4503, Stoneville, MS, USA. 11 pp.
Metabolic requirement for protein by pacific white shrimp Litopenaeus vannamei
- N Kuresh
- D A Davis
- L E Cruz-Suárez
- D Ricque-Marie
- M Tapia-Salazar
- Olvera-Novoa
Kuresh, N., Davis, D.A., 2000. Metabolic requirement for protein by pacific white
shrimp Litopenaeus vannamei. In: Cruz-Suárez, L.E., Ricque-Marie, D.,
Tapia-Salazar, M., Olvera-Novoa, M.A., Civera-Cerecedo, R. (Eds.), Avances en
Nutrición Acuícola V. Memorias del V Simposium Internacional de Nutrición
Acuícola. 19-22 Noviembre, 2000. Mérida, Yucatán, Mexico, pp. 161-180.
Indoor-raised shrimp find potential market in Kentucky State University test. Global Aquacult
- A J Ray
Ray, A.J., 2015. Indoor-raised shrimp find potential market in Kentucky State
University test. Global Aquacult. Advocate 18 (6), 76-77.
Feed formulation and on-farm feed management
- A G J Tacon
Tacon, A.G.J., 1993. Feed formulation and on-farm feed management. In: New,
M.B., Tacon, A.G.J., Csavas, I. (Eds.), Farm-made Aquafeeds. Proceedings of the
FAO/AADCP Regional Expert Consultation on Farm-Made Aquafeeds.
December 14-18, 1992, Bangok, Thailand. FAO-RAPA/AADCP, Bangkok,
Thailand, pp. 61-74.
Standard Methods for the Examination of Water and Wastewater
APHA (2005) Standard Methods for the Examination of
Water and Wastewater. 21st ed. American Public
Health Association, American Water Works Association, and Water Pollution Control Association Washington, DC, USA, 1200 pp.
Total Suspended Solids, Mass Balance (Dried at 103-105°C) Volatile Suspended Solids (Ignited at 550°C). Environmental Sciences Section, Inorganic Chemistry Unit
ESS (1993) ESS Method 340.2: Total Suspended Solids,
Mass Balance (Dried at 103-105°C) Volatile Suspended
Solids (Ignited at 550°C). Environmental Sciences Section, Inorganic Chemistry Unit, Wisconsin State Lab of
Hygiene, Madison, WI, USA, 4 pp.
Recirculating Aquaculture Cayuga Aqua Ventures
- M B Timmons
- J M Ebeling
Timmons M.B. & Ebeling J.M. (2007) Recirculating Aquaculture(2nd edn). Cayuga Aqua Ventures, Ithaca, NY,
USA, 948 pp.