Comparative Study of Astaxanthin, Cholesterol, Fatty Acid Profiles, and Quality Indices Between Shrimp Oil Extracted From Hepatopancreas and Cephalothorax

Shrimp oil from two different portions of Pacific white shrimp including cephalothorax and hepatopancreas was extracted using the mixture of hexane/isopropanol (1:1). The extracted oils from the cephalothorax (CPO) and hepatopancreas (HPO) were characterized for astaxanthin content, cholesterol levels, and fatty acid profiles. Nutrition indices of CPO and HPO were also compared. CPO had lower extraction yield (3.2 ± 0.1%, wet weight basis) than HPO (11.1 ± 0.5%, wet weight basis). High-performance liquid chromatography results indicated that the astaxanthin content in HPO was higher, compared to that of CPO. Nevertheless, the cholesterol level in HPO was 70% lower than that of CPO. Fatty acid profiles of HPO and CPO demonstrated that the polyunsaturated fatty acid (PUFA) content in HPO was higher than that of CPO. The amount of docosahexaenoic acid in the former was ~2 times higher than that of the latter. HPO contained 42.76 ± 0.36% PUFA, whereas PUFA content of CPO was 35.27 ± 0.19%. On the other hand, saturated fatty acids (SFA) were more pronounced in CPO (38.44 ± 0.26%) than HPO (30.82 ± 0.55%). Based on nutrition indices, namely, atherogenicity index, thrombogenicity index, hypocholesterolemic/hypercholesterolemic (h/H) ratio, and PUFA/SFA ratio, HPO possessed higher health benefit than CPO. The oxidation status of CPO and HPO measured in terms of peroxide value, thiobarbituric acid reactive substances, anisidine value, and conjugated dienes indicated that higher primary oxidation products were present in CPO, whereas HPO exhibited more secondary oxidation compounds. Fourier transform infrared spectra further substantiated the presence of oxidation products in CPO and HPO. Liquid chromatography-mass spectrometry identification showed the enhanced levels of phospholipids and glycolipids in the ethanolic fraction of CPO. Overall, HPO with a higher yield was more beneficial in terms of health benefits than CPO.

Sequential Continuous Mixotrophic and Phototrophic Cultivation Might Be a Cost-Effective Strategy for Astaxanthin Production From the Microalga Haematococcus lacustris

Although Haematococcus lacustris has been developed for astaxanthin production for decades, the production cost is still high. In order to modify the production processes, we proposed a novel strategy of cultivation, featured by sequential indoor continuous mixotrophic cultivation for the production of green cells followed by outdoor phototrophic induction for astaxanthin accumulation. The continuous mixotrophic cultivation was first optimized indoor, and then the seed culture of mixotrophic cultivation was inoculated into outdoor open raceway ponds for photoinduction. The results showed that mixotrophically grown cultures could efficiently grow without losing their photosynthetic efficiency and yielded higher biomass concentration (0.655 g L−1) and astaxanthin content (2.2% DW), compared to phototrophically grown seed culture controls. This novel strategy might be a promising alternative to the current approaches to advance the production technology of astaxanthin from microalgae.

Enhancement of astaxanthin accumulation using black light in Coelastrum and Monoraphidium isolated from Malaysia

Microalgae are important microorganisms which produce potentially valuable compounds. Astaxanthin, a group of xanthophyll carotenoids, is one of the most powerful antioxidants mainly found in microalgae, yeasts, and crustaceans. Environmental stresses such as intense light, drought, high salinity, nutrient depletion, and high temperature can induce the accumulation of astaxanthin. Thus, this research aims to investigate the effect of black light, also known as long-wave ultraviolet radiation or UV-A, as a stressor on the accumulation of astaxanthin as well as to screen the antioxidant property in two tropical green algal strains isolated from Malaysia, Coelastrum sp. and Monoraphidium sp. SP03. Monoraphidium sp. SP03 showed a higher growth rate (0.66 day−1) compared to that of Coelastrum sp. (0.22 day−1). Coelastrum sp. showed significantly higher accumulation of astaxanthin in black light (0.999 g mL culture−1) compared to that in control condition (0.185 g mL−1). Similarly, Monoraphidium sp. SP03 showed higher astaxanthin content in black light (0.476 g mL culture−1) compared to that in control condition (0.363 g mL culture−1). Coelastrum sp. showed higher scavenging activity (30.19%) when cultured in black light condition, indicating a correlation between the antioxidant activity and accumulation of astaxanthin. In this study, black light was shown to possess great potential to enhance the production of astaxanthin in microalgae.

Electric Stimulation of Astaxanthin Biosynthesis in Haematococcus pluvialis

The green microalga Haematococcus pluvialis accumulates astaxanthin, a potent antioxidant pigment, as a defense mechanism against environmental stresses. In this study, we investigated the technical feasibility of a stress-based method for inducing astaxanthin biosynthesis in H. pluvialis using electric stimulation in a two-chamber bioelectrochemical system. When a cathodic (reduction) current of 3 mA (voltage: 2 V) was applied to H. pluvialis cells for two days, considerable lysis and breakage of algal cells were observed, possibly owing to the formation of excess reactive oxygen species at the cathode. Conversely, in the absence of cell breakage, the application of anodic (oxidation) current effectively stimulated astaxanthin biosynthesis at a voltage range of 2–6 V, whereas the same could not be induced in the untreated control. At an optimal voltage of 4 V (anodic current: 30 mA), the astaxanthin content in the cells electro-treated for 2 h was 36.9% higher than that in untreated cells. Our findings suggest that electric treatment can be used to improve astaxanthin production in H. pluvialis culture if bioelectrochemical parameters, such as electric strength and duration, are regulated properly.

THE GROWTH AND DEVELOPMENT OF WHITE LEG SHRIMP PENAEUS VANNAMEI WHEN FEEDING WITH DIFFERENT TYPES OF MIXED FODDERS UNDER ARTIFICIAL CONDITIONS

The work evaluated the survival and growth of white leg shrimp Penaeus vannamei juveniles in recirculating water systems when feeding with different types of mixed fodders. It is shown that in the early stages of development from 25 to 150 days a fodder with negative buoyancy should be used. A protein content in a fodder between 45 to 57 %% does not affect the growth of the white leg shrimp aged from 85 to 150 days. The study found that in order to enhance the color intensity of commercial products, it is necessary to use fodders with high astaxanthin content. When using high-grade fodder for over the 150 days of cultivation, it is possible to obtain individuals with an average weight of 25 g.

Biomass and Astaxanthin Productivities of Haematococcus pluvialis in an Angled Twin-Layer Porous Substrate Photobioreactor: Effect of Inoculum Density and Storage Time

The microalga Haematococcus pluvialis is mainly cultivated in suspended systems for astaxanthin production. Immobilized cultivation on a Twin-Layer porous substrate photobioreactor (TL-PSBR) has recently shown promise as an alternative approach. In Vietnam, a TL-PSBR was constructed as a low-angle (15 °) horizontal system to study the cultivation of H. pluvialis for astaxanthin production. In this study, the biomass and astaxanthin productivities and astaxanthin content in the dry biomass were determined using different initial biomass (inoculum) densities (from 2.5 to 10 g dry weight m−2), different storage times of the initial biomass at 4 °C (24, 72, 120 and 168 h) and different light intensities (300–1000 µmol photons m−2 s−1). The optimal initial biomass density at light intensities between 400–600 µmol photons−2 s−1 was 5–7.5 g m−2. Algae stored for 24 h after harvest from suspension for immobilization on the TL-PSBR yielded the highest biomass and astaxanthin productivities, 8.7 g m−2 d−1 and 170 mg m−2 d−1, respectively; longer storage periods decreased productivity. Biomass and astaxanthin productivities were largely independent of light intensity between 300–1000 µmol photons m−2 s−1 but the efficiency of light use per mole photons was highest between 300–500 µmol photons m−2 s−1. The astaxanthin content in the dry biomass varied between 2–3% (w/w). Efficient supply of CO2 to the culture medium remains a task for future improvements of angled TL-PSBRs.

EFFECTS OF DIETARYASTAXANTHIN SUPPLEMENT ON GROWTH AND COLOR OF KOICARP (Cyprinus Carpio)

The study was conducted in order to find the astaxanthin content suitable for growth and color of Koi carp. The fish in the experiment with the length of 7.87 - 7.90cm and weight of 8.46–8.52g were set up in 4 treatments with 4 astaxanthin levels:0 mg (NT1), 55 mg (NT2), 65 mg (NT3), 75 mg /kg(NT4) food with 3 replicates. The results showed that environmental factors such as temperature, pH, N-NH3 and N-NO2 were within the suitable range for growth and color of Koi fish. Survival rate ranged from 46.67 to 66.67% (p> 0.05). Growth in length (15.26 - 15.55 cm) and weight (47.31 - 48.39 g) did not differ significantly between treatments (p> 0.05). Feed conversion ratio (FCR) between treatments was not different. The fish color index in NT3 was significantly higher than the others. Therefore, the content of 65 mg/ kg of food resulted in best color of Koi fish.