Protein‐dependent aquaculture generates large amounts of nutrient‐rich residuals; a feasible way to develop sustainable production systems is to integrate Decoupled Aquaponic Systems (DAPS) with ...residual water bioprocesses, to combine Photoautotrophic Biofloc Technology (P‐BFT) aquaculture and hydroponic horticulture. This study describes the characteristics of residual water from Oreochromis niloticus aquaculture performed with P‐BFT inoculated with Chlorella microalgae, reared during the nursery (180 fish m3) and grow‐out (55 fish m3) phases. The experiment included five treatments: photoautotrophic BFT inoculated with Chlorella sp. (M), C. sorokiniana 2714 (CV), and C. sorokiniana 2805 (CS), and chemoautotrophic (Q) and heterotrophic (H) as controls. Elemental characteristics in liquid and solid residual fractions (15 macro‐ and micronutrients) were compared among treatments and against Hoagland & Arnon solution with hydroponics and used in Nutrient Film Technique (NFT) hydroponic horticulture including five plant species: lettuce (Lactuca sativa), pak‐choi (Brassica rapa subsp. chinensis), rocket (Eruca sativa), spinach (Spinacia oleracea) and basil (Ocimum basilicum). The physicochemical parameters were ideal for O. niloticus and plants. The relationship between N:P was ideal until weeks 16–22 in the photoautotrophic treatments, compared with hydroponic solutions. Micronutrient content was greater in the solid than a liquid fraction. The best BFT effluent regarding fish and plant growth was photoautotrophic treatments. Oreochromis niloticus BFT aquaculture in photoautotrophic mode using microalgae Chlorella inoculations provided residual water beneficial to hydroponic horticulture in DAPS located in coastal arid zones where freshwater is scarce, improving aquaculture performance and reusing water and nutrients.
In this manuscript (Part I), the zootechnical performance of tilapia (Oreochromis niloticus) culture during the nursery and grow‐out phases using biofloc technology (BFT) with three photoautotrophic ...pathway treatments (Chlorella spp., M; Chlorella sorokiniana 2,805, CS; and Chlorella sorokiniana 2,714, CV) was evaluated using high protein feed (40.6%) at a C:N ratio of 7.69:1. Two additional treatments were included as controls: a chemoautotrophic (Q) treatment with a C:N ratio of 7.69:1 and a heterotrophic (H) treatment with a C:N ratio of 13:1. Differences in growth and weight gain were observed among the photoautotrophic treatments and Q and H treatments (p < .05). An increase in nitrates in all photoautotrophic treatments suggests that a chemoautotrophic pathway naturally occurred. For O. niloticus carcasses, the protein (>50.9%) and crude lipid (>23.1%) levels were not significantly different among treatments (p > .05). For the Q treatment, the highest crude protein (42.6%) and crude lipid (1.1%) levels in biofloc were observed during the nursery phase (p < .05). Correlation analyses between the amino acid composition in O. niloticus and that of the feed highlighted deficiencies with regard to methionine, lysine and threonine content despite the high r2 value obtained (.9078). In addition, deficiencies in arginine, lysine and taurine were observed in the biofloc (r2 = .7265). In Part II, the physicochemical characterization of nutrient residuals and O. niloticus BFT aquaculture integration with hydroponic horticulture in non‐recirculated systems is described.
White spot syndrome virus is a virulent pathogen that affects most crustaceans. Reactive oxygen species are produced by the immune system that defends the host against foreign microorganisms. This ...study examined the antioxidant enzymes and oxidative damage in tissues (hemolymph, digestive gland, gills, and muscle) of Pacific whiteleg shrimp (Litopenaeus vannamei) infected with the disease by intramuscular injection of the virus. Viral loads were confirmed by real-time PCR. The levels of oxidative damage (lipid peroxidation and protein carbonyl), the activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase) were quantified in uninfected and infected tissues. Lipid peroxidation and protein carbonyl levels were higher in infected specimens compared to uninfected controls. A significant reduction in antioxidant enzyme activities was found at 48h post-infection in all tissues analyzed. These results suggest that oxidative stress and tissue damage via inactivation of antioxidant enzymes in infected shrimps result in system failure and sudden death.
► We examined antioxidants and oxidative damage in WSSV-infected Pacific white shrimp. ► Reduced antioxidant enzyme activities were found at 48h post-infection. ► Oxidative stress occurred via inactivation of antioxidant enzymes in WSSV-infected shrimp.
Dietary fish oil can potentially be replaced by camelina oil in aquafeeds since 18:3n‐3 (α‐linolenic acid: ALA) accounts for 35% of the fatty acids. To test the effect of camelina oil on fish lipid ...composition, a feeding trial with tilapia (var. GIFT Oreochromis sp.) was carried out. Four experimental diets were formulated, one containing only fish oil (TFO), two where fish oil was replaced by camelina at low (Low‐CO) and medium (Med‐CO) levels, and another made only with camelina oil (TCO). A commercial diet (COM) was used as a reference diet. At the end of an 8‐week feeding trial, the liver, kidney, heart and brain were sampled. In terms of proportions across tissues, the liver showed the highest triacylglycerol and oleic acid content; the kidney was higher in arachidonic (ARA) and eicosapentaenoic acid (EPA); the heart had the highest total lipids, linoleic acid (LOA) and ALA, while the brain was higher in sterols, acetone‐mobile polar lipids (AMPL), phospholipids and docosahexaenoic acid (DHA). In terms of concentration among diets within tissues, when comparing TFO vs TCO, the phospholipids and ARA increased in the kidney, while the phospholipids decreased in the heart and the DHA in the brain. The TCO diet significantly increased 20:1n‐9 and ALA in all analysed tissues. As expected, the COM diet significantly increased concentrations of EPA, docosapentaenoic acid (n‐3DPA) and DHA in all analysed tissues.
The global aquaculture has shown an impressive growth in the last decades contributing with a major part of total food fish supply. However, it also helps in the spread of diseases that in turn, ...causes great economic losses. The White Spot Syndrome Virus (WSSV) is one of the major viral pathogen for the shrimp aquaculture industry. Several attempts to eliminate the virus in the shrimp have been addressed without achieving a long-term effectiveness. In this work, we determine the capacity of the commercial non-toxic PVP-coated silver nanoparticles to promote the response of the immune system of WSSV-infected shrimps with or without an excess of iron ions. Our results showed that a single dose of metallic silver in the nanomolar range (111 nmol/shrimp), which is equivalent to 12 ng/mL of silver nanoparticles, produces 20% survival of treated infected shrimps. The same concentration administered in healthy shrimps do not show histological evidence of damage. The observed survival rate could be associated with the increase of almost 2-fold of LGBP expression levels compared with non-treated infected shrimps. LGBP is a key gene of shrimp immunological response and its up-regulation is most probably induced by the recognition of silver nanoparticles coating by specific pathogen-associated molecular pattern recognition proteins (PAMPs) of shrimp. Increased LGBP expression levels was observed even with a 10-fold lower dose of silver nanoparticles (1.2 ng/shrimp, 0.011 nmol of metallic silver/shrimp). The increase in LGBP expression levels was also observed even in the presence of iron ion excess, a condition that favors virus proliferation. Those results showed that a single dose of a slight amount of silver nanoparticles were capable to enhance the response of shrimp immune system without toxic effects in healthy shrimps. This response could be enhanced by administration of other doses and might represent an important alternative for the treatment of a disease that has still no cure, white spot syndrome virus.
Camelina oil (CO) is a potential replacement for fish oil (FO) in aquaculture feeds. CO is high in α-linolenic acid (18:3n-3 or ALA) (35%), with an omega-3/omega-6 (n-3/n-6) ratio near 2. In order to ...test the effect of CO on the overall performance of tilapia (Oreochromis niloticus var. GIFT), feed utilization, lipid composition and capacity to synthesize the long-chain fatty acids eicosapentaenoic acid (20:5n-3 or EPA) and docosahexaenoic acid (22:6n-3 or DHA) from ALA, were tested in an 8-week feeding trial with juvenile tilapia. The average fish weight at the start was 28 ± 6 g and they were grown in a biofloc system. Four dietary treatments were formulated, two containing either fish oil (TFO) or camelina oil (TCO), and two more where FO was replaced by CO at low (Low-CO) and mid (Mid-CO) levels. A commercial diet (COM) was used as a reference diet. Compound-specific stable isotope analysis (CSIA) and stable isotope mixing models with R software (SIAR) were used to calculate the contribution of ALA to EPA and DHA synthesis. At the end of the experiment, replacing FO by CO had no effect on growth (139 ± 22 g fish−1) or total lipid in the muscle (2.2–2.9 g). However, the tilapia fed TCO had significantly more phospholipid in muscle compared to tilapia fed TFO. Also, a higher content of linoleic acid (18:2n-6 or LOA) and ALA was revealed. ALA content in muscle followed the ALA content in diets; by contrast, EPA and DHA decreased significantly as the level of dietary CO increased. Despite the variation in fatty acids, n-3 PUFA and the n-3/n-6 ratio in muscle tissue did not show differences among experimental diets. CSIA revealed that the δ13C isotopic signature of DHA in tilapia muscle after feeding TCO and biofloc was slightly but significantly enriched in (Budge et al., 2008)C. However, CO feeding resulted in a significantly depleted isotopic signal for docosapentaenoic acid (22:5n-3 or DPA) compared to FO. SIAR indicated that 28% of DHA, 36% of EPA, and 40% of DPA was synthesized from camelina oil ALA.
•The total replacement of fish oil by camelina oil in the diet for tilapia not decreased the growth performance.•Camelina oil not increased EPA + DHA in fillet as fish oil did but produced an adequate n-3/n-6 ratio for human diet.•The CSIA showed that 28–40% of n-3 LC-PUFA in tilapia muscle could be synthesized from camelina oil ALA.
The whiteleg shrimp Penaeus (Litopenaeus) vannamei is one of the most relevant aquaculture species in Latin America and globally. Among several elements, the improvement of its production depends on ...the larval genetic quality produced in commercial hatcheries. A strategy for achievement is setting up a long-term management plan that includes the genetic settlement of a breeding population with broad genetic variability and reduced inbreeding levels and the design of adequate management and crossbreeding schemes. The settlement of the breeding population requires a detailed characterization of the genetic composition and diversity of the breeding line(s) that are being managed. The present study evaluated the genetic composition of six wild populations from the southern and northern coasts of the Mexican Pacific (Oaxaca, Guerrero, Nayarit, and Sinaloa) and 56 breeding lots maintained in commercial hatcheries. The genetic profiles of a low-density SNP marker panel (171 and 152 loci for the wild and hatchery-reared groups, respectively) were used to estimate genetic diversity and differentiation within and among samples. The wild population presented significant genetic differences between southern and northern Pacific locations. Although these populations showed higher diversity levels than the cultivated stocks, the genetic pool of the total 56 lots was highly variable with low inbreeding levels. The genetic characteristics of the analyzed populations and cultivated stocks warrant the constitution of a Mexican-origin breeding line with future potential for selection to the environmental conditions of the northwestern region of Mexico.
This research study tested the protective effect of prolonged exposure of shrimp food supplemented with glucans from shrimp-pond related yeasts on shrimp Penaeus vannamei reared under the presence of ...the white spot syndrome virus (WSSV). The glucans extracted and purified from isolated marine yeasts identified as Debaryomyces hansenii, Candida tropicalis, Candida humilis, Candida glabrata, Pichia kudriavzevyi, Wickerhamomyces anomalus and the terrestrial Saccharomyces cerevisiae yeast were characterized by the Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The treatments were prepared with food enriched with the yeast beta-glucans and the control groups without beta-glucans. Shrimp were fed thrice a day and challenged orally with WSSV on days 31, 54, 66 and muscularly at day 70. The animals were assessed for the protective effect in terms of post-infection total hemocyte counts, and survival rate. The results indicated that marine yeasts possessed ß-1,3/1,6-glucans, and that D. hansenii was an excellent source yielding 30% of its dry biomass of pure glucans. For the positive control group where no glucans were added, WSSV challenges showed 100% survival when the virus was provided orally, and 40% when the virus was injected. These results also indicated that the shrimp line selected for this study was a resistant line for WSSV. Shrimp groups fed with glucans of the marine yeasts D. hansenii and C. humillis showed a significant protection, allowing shrimp survival of 66% while terrestrial yeast showed 57.14%. These results indicated that marine yeasts growing in the shrimp pond were an excellent source of beta-glucans that allowed extra protection against the mortality caused by this pathogenic virus.
Recirculating aquaculture systems (RASs) are an efficient method for developing sustainable aquaculture and the development of a feed strategy for RASs could be a key factor for the success of ...culturing Oreochromis niloticus. The daily protein intake (DPI) mathematical function related to body weight (BW) was designed (DPI = −3.818 ln (BW) + 30.158) named DPI 1.0 = 100%. Three feeding rates were established, DPI 1.4, 1.2 and 1.0, and were implemented in an RAS production cycle (100 fish/m3) for 34 weeks. The final growth measurements were 908.0 ± 57.9 g (DPI 1.4), 887.0 ± 113.5 g (DPI 1.2) and 702.2 ± 38.1 g (DPI 1.0) (p < .05), with feed conversion rates (FCRs) of 2.3, 1.9 and 1.9, respectively; the survival was ≥ 98.3% (p > .05) for all treatments. DPI levels conditioned the growth of the fish and the proportion of lipid: protein in the bodies of O. niloticus but not in the fillets. The mathematical function DPI 1.2 = 120% (DPI = −4.582 ln (BW) + 36.19) used in the RAS at the 40% protein level improved fish growth, the protein efficiency ratio and FCRs. The DPI values were estimated for 49 different cases and feeding strategies showed lower values than most of the different DPI mathematical functions used and cited in this work. Therefore, DPI metric is a good tool that provides the specific requirements of protein for O. niloticus growth, which can enable farmers to ration feed and improve energy use (kWh/fish) and facilitate the integration of RAS with horticulture.
The aquaculture industry faces many challenges regarding the intensification of shrimp rearing systems. One of these challenges is the release of excessive amounts of nitrogen and phosphorus into ...coastal areas, causing disruption in nutrient cycling and microbial equilibrium, which are important for coastal productivity. Biosecurity within the shrimp rearing systems can also be compromised by disruption to the nutrient fluxes, and as consequence the microbiome of the system. In certain conditions, these changes could lead to the blooming of potentially pathogenic bacteria. These changes in the external microbiome of the system and the constant fluctuations of nutrients can affect the intestinal microbiome of shrimp, which is involved in the growth and development of the host, affecting nutrient absorption, regulating metabolic processes, synthesising vitamins, modulating the immune response and preventing growth of pathogenic bacteria. It has been suggested that specific changes in the intestinal microbiome of
Litopenaeus vannamei
may be an avenue through which to overcome some of the problems that this industry faces, in terms of health, growth and waste. Recent research, however, has focussed mainly on changes in the intestinal microbiome. Researchers have overlooked the relevance of other aspects of the system, such as the microbiome from the benthic biofilms; zooplankton, plankton and bacterioplankton; and other sources of microorganisms that can directly affect the microbial status of the intestinal and epiphytic communities, especially in rearing systems that are based on intensification and microbial maturation processes, such as a biofloc system. It is therefore necessary to place holobiome studies into context, including the ‘holobiome of the aquaculture system’ (microbiomes that make up the culture system and their interactions) and not only the intestinal microbiome. Thus, we describe factors that affect the shrimp microbiome, the methodology of study, from sampling to bioinformatic workflows, and introduce the concept of the ‘holobiome of the aquaculture system’ and how this enables us to promote the intensification, biosafety and eco-efficiency of shrimp farming. The holobiome perspective implies a greater investment of resources and time for research, but it will accelerate the development of technology that will benefit the development and sustainability of the aquaculture industry.
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