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The present study investigated the impact of seasonal variation on biomass availability, proximate composition, fatty acid profile, minerals content, pigments, moisture content, and elemental composition of an edible green alga Gayralia brasiliensis collected from Shirgaon estuary Maharashtra, west coast of India. Additionally, the physico-chemical parameters of the Shirgaon estuary were analyzed and correlated with biomass abundance and biochemical composition of G. brasiliensis. The findings of the present study demonstrated a significant variation in the physico-chemical parameters of seawater throughout the seasons. During the summer season, the biomass abundance (258.23 ± 23.06 g m-2 FW), and the total protein content (11.12 ±1.37 % DW) were found highest while the total lipid content declined considerably. Nonetheless, the contents n-6 and n-3 PUFA increased significantly over the winter season. The concentration of micro-elements was highest during the winter season while the macro-elements found plenty during the monsoon season. The correlogram analysis revealed that biomass, total protein, total carbohydrate, chlorophyll pigments, and tissue C, H, N, and S were positively correlated with each other throughout all three seasons. Based on Pearson corelation analysis it is confirmed that among the environmental parameters, irradiance and temperature were found the most limiting factors for the growth of G. brasiliensis. Further, dissolved inorganic nitrate significantly influence the growth of G. brasiliensis negatively. Overall, the results of this study imply that G. brasiliensis should be harvested for desired metabolites during the respective seasons. The findings of the present study are expected to be extremely valuable for future cultivation strategies and edible applications of G. brasiliensis in India. [ABSTRACT FROM AUTHOR]

Polyunsaturated fatty acid (PUFA) and eicosapentaenoic acid (EPA) are essential for the health of aquatic organisms and human beings. In order to optimize the culture conditions of the diatom Chaetoceros lorenzianus, effects of different iron sources (FeC6H5O7, FeCl3, FeSO4) and different iron concentrations (0.10, 0.25, 0.50, 0.75, 1.00, 1.25 mg L−1) on C. lorenzianus were studied. The results showed that different iron sources and different iron concentrations had significant effects on the growth, chlorophyll a, total lipid and fatty acids of C. lorenzianus. The growth rate (0.47 day−1), chlorophyll a (510.57 μg L−1), total lipids (11.82%), and n-3 PUFA (EPA and DHA) (21.20%) contents were significantly higher in the FeCl3 group when compared to FeSO4 and FeC6H5O7 groups. The optimum concentration of FeCl3 for the growth and synthesis of chlorophyll a was 0.75–1.00 mg L−1 and the optimum concentration for lipid accumulation was 0.25 mg L−1. The secondary culture method can be used in large-scale culture, that is, the initial culture is performed under the optimal iron concentration (0.75 mg L−1 FeCl3) for obtaining higher biomass. Then, the secondary culture would be performed under a low iron concentration (0.25 mg L−1 FeCl3), obtaining high total lipids in algal cells. These findings make tangible contributions to culture C. lorenzianus for potential commercial production of PUFA and EPA. [ABSTRACT FROM AUTHOR]

The steady demand for fish in the aquaculture sector has led to the study and implementation of new compounds of natural origin which seek to standardize and maximize production by ensuring reproductive performance. Microalgae have emerged as a renewable source with specific nutritive qualities that allows the enhancement of captive breeding, and the use of local strain aims to facilitate cultivation and reduce production costs. Therefore, in this study, the effect of a diet supplemented with a diatom of the genus Grammatophora obtained from La Paz Bay, Mexico, was evaluated on the reproductive performance of 5-year-old Pacific Red snapper (Lutjanus peru). Two isoproteic and isolipidic diets were compared: the control semi-humid diet (R0) and the experimental enriched diet with 3% of Grammatophora sp. silage made by fermentation (R1). Fishes were fed ad libitum 3 months previous to the spawning season during 7 months. Hatching rate was significantly (P < 0.05) higher for R1 eggs (77%) compared to control (39–64%). For R0, egg sizes fluctuated significantly during the spawning season and presented an average diameter of 782.4 ± 5.5 µm. For R1, the egg diameter, significantly larger (792.5 ± 4.1 µm), was stable throughout the season. Finally, R1 eggs had significant higher polyunsaturated fatty acid content (arachidonic, eicosapentaenoic and docosahexaenoic acids) compared to R0 eggs (P < 0.05). In conclusion, supplemented mature L. peru with 3% of Grammatophora sp. silage in fish, prior and during spawning season, is recommended to improve their reproductive performance (hatching rate, egg size and egg quality) and ensure larval production. [ABSTRACT FROM AUTHOR]

The fatty acid profiles of the three lipid fractions, neutral lipids (NL), free fatty acids and polar lipids (PL), from the macroalgae Palmaria palmata (wild), Alaria esculenta (cultivated) and Saccharina latissima (cultivated) were studied in light of dietary important fatty acids. Blade and stipe from the macroalgae were collected at the end of the growth season (May/June) at Frøya (Trøndelag, Norway). A total of 51 fatty acids were identified in the algae, including several fatty acids novel to one or more of the algae. The NL and PL fractions of P. palmata were the most promising from a health perspective, due to a high content of eicosapentaenoic acid (10.1 ± 0.5% and 6.6 ± 0.1%, respectively) and no trans-fatty acids. In addition, these fractions had very low omega-6/omega-3 ratios (< 0.1) and can therefore be beneficial for balancing the omega-6/omega-3 ratio in the diet. The NL fraction of A. esculenta had the highest content of monounsaturated- and polyunsaturated fatty acids (20.9 ± 1.4 and 21.8 ± 1.9% of alga, respectively), as well as the highest content of the two essential fatty acids, linoleic acid (5.3 ± 0.4% of alga) and alpha-linolenic acid (2.4 ± 0.2% of alga). Indices related to risk factors for coronary heart disease were most favourable in the NL fraction of S. latissima and the NL and PL fractions of A. esculenta. [ABSTRACT FROM AUTHOR]

Diatoms are of great interest for large-scale cultivation due to their high lipid content. The ability to grow over a wide range of salinities is also of great advantage. We studied the effect of temperature and salinity on the growth, lipids and fatty acid profiles of a newly isolated halophilic diatom Amphora sp. MUR 258. Amphora sp. MUR 258 is unusual in that it grows over a wide range of temperatures (24–35 °C) and salinities (7–12% (w/v) NaCl). The highest specific growth rate (SGR; 0.607 ± 0.017 day−1) was achieved at 7% NaCl at 35 °C, and the lowest SGR (0.433 ± 0.087 day−1) was obtained at 9% NaCl at 25 °C. The cells contained more lipids in the exponential phase, except when grown at 12% NaCl where the lipid content was higher in the stationary phase. The alga achieved its highest lipid content (57.69 ± 2.039% ash-free dry weight (AFDW) when grown at 7% NaCl at 25 °C and the lowest (34.43 ± 3.955% AFDW) obtained at 12% NaCl at 35 °C. The highest biomass productivity (0.171 ± 0.017 gAFDW L−1 day−1) and the lipid productivity (0.062 ± 0.017 gAFDW L−1 day−1) were achieved when the Amphora were grown at 9% NaCl at 35 °C and 7% at 25 °C, respectively. Irrespective of the growth conditions, the predominant fatty acids of Amphora sp. MUR 258 were palmitic acid (C16:0), stearic acid (C18:0), palmitoleic acid (C16:1) and oleic acid (C18:1), as well as low quantities of eicosapentaenoic acid (C20:5). [ABSTRACT FROM AUTHOR]

Microalgal cultivation in aquaculture wastewater (AWW) from recirculating aquaculture systems (RAS) is an approach for combined production of valuable algal biomass and AWW treatment. The growth, nutrient uptake, fatty acid (FA) profile, and tocopherol content of mixed algal cultures of Euglena gracilis with Selenastrum grown in AWWs from pikeperch (Sander lucioperca) and catfish (Clarias anguillaris) RAS were studied. The highest algal biomass (1.5 g L−1), lipid (84.9 mg L−1), and tocopherol (877.2 μg L−1) yields were achieved in sludge-amended pike perch AWW. Nutrient removal rates in experiments were 98.9–99.5 and 98.4–99.8% for NH4-N and PO4-P, and 75.4–89.2% and 84.3–95.7% for TN and TP, respectively, whereas the COD was reduced by 45.8–67.6%. Biomass EPA and DHA content met, while ARA and tocopherol content exceeded the requirements for fish feed. Algal cultivation in AWWs is a promising alternative for AWW treatment while providing a replacement for fish oil in feed. [ABSTRACT FROM AUTHOR]

Among several sustainable resources, marine heterotrophic microorganisms have gained much interest for various commercial applications owing to their potential to produce high quantities of polyunsaturated fatty acids. Above 70% of the globally produced fish oil is utilised for aqua feed formulations. Intense research is being carried out to find suitable alternatives to fish oil. Oleaginous protists are being explored as a promising substitute to fish oil and also for various high-value-added products. However, characterisation and utilisation of these unique protists remain underexplored in many countries including India and this prompted us to screen and isolate these heterotrophic microorganisms capable of producing PUFAs. In this study, 11 strains of heterotrophic thraustochytrid capable of producing significant quantities of polyunsaturated fatty acids were successfully isolated from different mangrove habitats along the southwest coast of India. Morphological characterisation along with molecular identification revealed that these strains showed close similarity to Aurantiochytrium spp. of the family Thraustochytridae. They are able to produce 7–11 g of dry biomass per litre of culture. Their fatty acid content was up to 12% (wt/wt) of biomass and GC analysis confirmed that these protists can accumulate docosahexaenoic acid as high as 22–60% of the total fatty acids. Their enzymatic activity, tolerance to various abiotic stress factors and antagonistic potential against vibrios are also described. These heterotrophic protists can antagonise aquaculture pathogens and act as an excellent source of docosahexaenoic acid that indicates their potential as a sustainable alternative to fish oil. [ABSTRACT FROM AUTHOR]

Hydrurus foetidus (Villars) Trevisan is a benthic freshwater alga in the class Chrysophyceae. Under seasonal climate regimes, it may be found in rivers during the cold seasons. It is widely distributed in cold-temperate, polar, and periglacial regions. Its heavy extracellular polysaccharide coating and its importance as food for grazers under cold conditions may indicate a potential for applied purposes. The strain G 070301 has been kept in culture since 2007. In this presentation, we have fine-tuned our laboratory culturing, detected the presence and positions of lipids in the cells by fluorescence imaging, and performed a preliminary analysis of the unsaturated fatty acids in Hydrurus grown on minimal medium. Little is known about the physiological adaptability of chrysophytes for applied purposes. Following optimization of media and a simple harvesting technology, the psychro- and rheophilic species H. foetidus may have a future as a source of polyunsaturated fatty acids for inland aquaculture and for polysaccharides. [ABSTRACT FROM AUTHOR]

Increasingly, macroalgae are being recognised as a growth opportunity for functional foods and nutritional security in the future. Dominating traits of interest are metabolites that function as anti-inflammatories and are antiproliferative. However, seaweeds from the northern hemisphere dominate this field of research. Australia has a unique flora of macroalgae, and it is poorly understood which species should be targeted for cultivation towards food and health markets. Here, six Australian marine macroalgae were selected for screening of one anti-inflammatory group; n-3 polyunsaturated fatty acids (PUFA). PUFA profiles were determined using gas chromatography-mass spectrometry and multivariate analysis. Thirty-one fatty acids (FA) were identified across the six macroalgal species with C16:0 the dominant FA in all samples, variations across taxa in the saturated FA C10:0, C14:0, C16:0, C18:0 and C20:0 and variations in monounsaturated FA attributed to C16:1 n-7 and C18:1 n-9. For PUFA profiles, all six species had significantly different n-6/n-3 ratios, while the green seaweed Ulva species possessed the lowest n-6/n-3 ratio of 0.4, along with a 2-fold higher C18:3 n-3 to C18:2 n-6 content. Ulva sp. was the only species that contained docosahexaenoic acid. Extracts of both the Ulva sp. and Hormosira banksii showed selective cytotoxicity towards a human pancreatic cancer cell line, while the nonpolar extracts of all six algae species strongly inhibited production of the inflammatory-mediator nitric oxide. [ABSTRACT FROM AUTHOR]

We investigated the spatial, seasonal, and within-plant variation in total fatty acids (TFA) and fatty acid (FA) composition in the brown seaweeds Dictyota bartayresii sampled from Nelly Bay, Orpheus Island, and Kissing Point (Northern Queensland, Australia) and Dictyopteris australis sampled from Nelly Bay. Both species were present year round, but with no consistent seasonal pattern in plant size, and had an annualized mean content of TFA of 5 % dry weight (dw) that is among the highest recorded for seaweeds. For Dictyota, larger plants had a higher content of TFA and a higher proportion of polyunsaturated omega-3 FA (PUFA(n-3)) than smaller plants, while for Dictyopteris, the TFA content and the proportion of PUFA(n-3) were unrelated to plant size. TFA in Dictyota varied considerably between locations (~40 %) (3.5-5.5 % dw) and to a lesser degree between seasons (~10 %) with a lower content of TFA and higher proportion of PUFA(n-3) in winter. Dictyopteris had an ~10 % higher content of TFA in winter but with no seasonal pattern in the composition of FA. There was also within-plant variation in FA, as TFA decreased from the tips toward the base in both species, and in Dictyopteris, the tips had a higher proportion of saturated FA (SFA) and PUFA(n-3) than the base. The presence of site- and species-specific variation in the content and composition of fatty acids reinforces the need for detailed analyses of the biochemical profile of seaweed biomass, including their extracts or purified compounds, if the focus is nutritional applications based on lipids. [ABSTRACT FROM AUTHOR]

In order to study the effects of different nitrogen source and concentrationon the growth rate and fatty acid composition, a marine microalga Ellipsoidion sp. with a high content of eicosapentaenoic acid (EPA) wascultured in media with different nitrogen sources and concentrations.During the pre-logarithmic phase, the alga grew faster with ammoniumas N source than with nitrate, but the reverse applied during thepost-logarithmic phase. The alga grew poorly in N-free mediumor medium with urea as the sole N source. In the same growth phase,ammonium medium resulted in higher yield of total lipid, but the EPA yielddid not differ significantly different from that using nitrate medium. Themaximum growth rate occurred in medium containing 1.28 mmolL-1 sodium nitrate, while maximum EPA and total lipid contents werereached at 1.92 mmol L-1, when EPA accounted for 27.9% totalfatty acids. The growth rate kept stable when NH4Cl ranged from0.64 to 2.56 mmol L-1, and the maximum content of total lipidand EPA occurred in the medium with 2.56 mmol L-1NH4Cl. The EPA content was higher in the pre- thanpost-logarithmic phase, though the total lipid content was lower. Thehighest EPA content expressed as percent total fatty acid was 27.9% innitrate medium and and 39.0% in ammonium medium. [ABSTRACT FROM AUTHOR]