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Canthaxanthin and β-apo-8'-carotenoid ethyl ester are widely used as feed additives in poultry feed for enhancing the color of poultry products. The excessive intake of the two colorants can cause health damage. According to the European Food Safety Authority (EFSA), the acceptable daily intake (ADI) of canthaxanthin and β-apo-8'-carotenoid ethyl ester are 0.03 mg/kg·bw and 0.015 mg/kg·bw, respectively. Ultra-high-performance liquid chromatography-diode array detector (UPLC-DAD) was used to determine two colorants in chicken eggs and meat. A PRiME HLB solid-phase extraction cartridge was used to extract and clean-up the sample. BEH C18 column was used as the separation column, with water containing 0.1% formic acid and acetonitrile as the mobile phase. The limit of detection (LOD) was 0.05 mg/kg, and the limit of quantification (LOQ) was 0.1 mg/kg. The recoveries were between 90% and 104%. The daily intake of two colorants in chicken eggs and meat was evaluated based on the detection data, food consumption data and weight data of the population. The mean estimated daily intake (EDI) values of canthaxanthin through chicken eggs and meat were 1.09 µg/(kg·bw·d) and 0.013 µg/(kg·bw·d), respectively. The mean EDI value of β-apo-8'-carotenoid ethyl ester through eggs was 0.44 µg/(kg·bw·d). The results showed that eggs were the main contributor to the daily intake of two colorants. The mean hazard quotients (HQ) values of two colorants through chicken eggs and meat was within a safe range. [ABSTRACT FROM AUTHOR]

Background: Canthaxanthin is a ketocarotenoid with high antioxidant activity, and it is primarily produced by microalgae, among which Nannochloropsis oceanica, a marine alga widely used for aquaculture. In the last decade, N. oceanica has become a model organism for oleaginous microalgae to develop sustainable processes to produce biomolecules of interest by exploiting its photosynthetic activity and carbon assimilation properties. N. oceanica can accumulate lipids up to 70% of total dry weight and contains the omega-3 fatty acid eicosapentaenoic acid (EPA) required for both food and feed applications. The genome sequence, other omics data, and synthetic biology tools are available for this species, including an engineered strain called LP-tdTomato, which allows homologous recombination to insert the heterologous genes in a highly transcribed locus in the nucleolus region. Here, N. oceanica was engineered to induce high ketocarotenoid and canthaxanthin production. Results: We used N. oceanica LP-tdTomato strain as a background to express the key enzyme for ketocarotenoid production, a β-carotene ketolase (CrBKT) from Chlamydomonas reinhardtii. Through the LP-tdTomato strain, the transgene insertion by homologous recombination in a highly transcribed genomic locus can be screened by negative fluorescence. The overexpression of CrBKT in bkt transformants increased the content of carotenoids and ketocarotenoids per cell, respectively, 1.5 and 10-fold, inducing an orange/red color in the bkt cell cultures. Background (LP) and bkt lines productivity were compared at different light intensities from 150 to 1200 µmol m-2 s-1: at lower irradiances, the growth kinetics of bkt lines were slower compared to LP, while higher productivity was measured for bkt lines at 1200 µmol m-2 s-1. Despite these results, the highest canthaxanthin and ketocarotenoids productivity were obtained upon cultivation at 150 µmol m-2 s-1. Conclusions: Through targeted gene redesign and heterologous transformation, ketocarotenoids and canthaxanthin content were significantly increased, achieving 0.3% and 0.2% dry weight. Canthaxanthin could be produced using CO2 as the only carbon source at 1.5 mg/L titer. These bkt-engineered lines hold potential for industrial applications in fish or poultry feed sectors, where canthaxanthin and ketocarotenoids are required as pigmentation agents. [ABSTRACT FROM AUTHOR]

Brine shrimp (Artemia), rich in carotenoids, are widely used in intensive aquaculture to supplement nutrients and enhance the coloration of farmed organisms. This study investigates the growth, reproduction, and carotenoid accumulation in Artemia sinica under varying salinity and temperature conditions. The results showed that temperature and salinity displayed significant interactions with survival, body length, and carotenoid accumulation in the body. The optimal survival and growth conditions of A. sinica (Bohai Sea Gulf) were a temperature range of 25–30 °C and a salinity range of 30–50‰. High temperatures accelerated growth and sexual maturity at the expense of survival rates, while temperatures below 20 °C prevented ovigerous development. Extreme salinity levels negatively affected survival and growth, though high salinity promoted sexual maturity. Carotenoids in A. sinica mainly accumulate as echinenone and canthaxanthin form. Carotenoid accumulation decreased with increased temperature and salinity, and the temperature effect decreased with rising salinity. A. sinica cultivated at a salinity of 10‰ and a temperature of 25 °C exhibits the highest carotenoid content. Transcriptomic analysis revealed that high temperatures primarily affected genes related to stress response and metabolism, while high-salinity regulated genes associated with ion balance and signaling pathways. These findings provide a theoretical basis for enhancing Artemia sinica aquaculture and optimizing cultivation conditions, offering novel insights into nutritional and environmental impacts on brine shrimp biology. [ABSTRACT FROM AUTHOR]

Gelatine (GL) is widely available as a microencapsulated material that prevents the decomposition of canthaxanthin (CX). However, there are still disadvantages such as instability, poor safety, and chromium overload. Our study aimed to determine the effects of using Lignosulfonate (LS) as a potential substitute to GL microencapsulation of CX on the productive performance, egg quality, yolk colour, and serum biochemical indicators of laying hens, as well as the optimal dosage. 1458 healthy ISA brown hens were divided into 9 treatments (162 birds in each group): basal diet containing 0 mg/kg CX (Control), basal diet containing 2 mg/kg GL-microencapsulated CX (GMC2), 4 mg/kg GL-microencapsulated CX (GMC4), 6 mg/kg GL-microencapsulated CX (GMC6), 8 mg/kg GL-microencapsulated CX (GMC8), basal diet containing 2 mg/kg LS-microencapsulated CX (LMC2), 4 mg/kg LS-microencapsulated CX (LMC4), 6 mg/kg LS-microencapsulated CX (LMC6), 8 mg/kg LS-microencapsulated CX (LMC8). The productive performance of each group was recorded daily for 4 weeks. Egg samples were collected and analysed weekly. Serum samples were taken at the end of the experimental period. The results showed that CX-containing diets had no significant effects on laying performance and egg quality (p > .05). The yolk colour level of the CX group was higher than the control group (p

Abstract Background Canthaxanthin is a ketocarotenoid with high antioxidant activity, and it is primarily produced by microalgae, among which Nannochloropsis oceanica, a marine alga widely used for aquaculture. In the last decade, N. oceanica has become a model organism for oleaginous microalgae to develop sustainable processes to produce biomolecules of interest by exploiting its photosynthetic activity and carbon assimilation properties. N. oceanica can accumulate lipids up to 70% of total dry weight and contains the omega-3 fatty acid eicosapentaenoic acid (EPA) required for both food and feed applications. The genome sequence, other omics data, and synthetic biology tools are available for this species, including an engineered strain called LP-tdTomato, which allows homologous recombination to insert the heterologous genes in a highly transcribed locus in the nucleolus region. Here, N. oceanica was engineered to induce high ketocarotenoid and canthaxanthin production. Results We used N. oceanica LP-tdTomato strain as a background to express the key enzyme for ketocarotenoid production, a β-carotene ketolase (CrBKT) from Chlamydomonas reinhardtii. Through the LP-tdTomato strain, the transgene insertion by homologous recombination in a highly transcribed genomic locus can be screened by negative fluorescence. The overexpression of CrBKT in bkt transformants increased the content of carotenoids and ketocarotenoids per cell, respectively, 1.5 and 10-fold, inducing an orange/red color in the bkt cell cultures. Background (LP) and bkt lines productivity were compared at different light intensities from 150 to 1200 µmol m-2 s-1: at lower irradiances, the growth kinetics of bkt lines were slower compared to LP, while higher productivity was measured for bkt lines at 1200 µmol m-2 s-1. Despite these results, the highest canthaxanthin and ketocarotenoids productivity were obtained upon cultivation at 150 µmol m-2 s-1. Conclusions Through targeted gene redesign and heterologous transformation, ketocarotenoids and canthaxanthin content were significantly increased, achieving 0.3% and 0.2% dry weight. Canthaxanthin could be produced using CO2 as the only carbon source at 1.5 mg/L titer. These bkt-engineered lines hold potential for industrial applications in fish or poultry feed sectors, where canthaxanthin and ketocarotenoids are required as pigmentation agents.

Unconventional oleaginous yeast Yarrowia lipolytica has gained widespread applications as a microbial cell factory for synthesizing various chemicals and natural products. The construction of efficient cell factories requires intricate metabolic engineering. However, multi-gene expression in Y. lipolytica is labor-intensive. To facilitate multi-gene expression, we developed the polycistronic expression tool using 2A peptides. We first compared different 2A peptides in Y. lipolytica and identified two 2A peptides with high cleavage efficiency: P2A and ERBV-1. The effect of 2A peptides on the expression level of upstream and downstream genes was then determined. Ultimately, we applied the identified 2A peptides to express four genes in canthaxanthin biosynthetic pathway within one expression cassette for canthaxanthin production. This study enriches the multi-gene expression tools of Y. lipolytica, which will facilitate the cell factory construction of Y. lipolytica.

Normal‐phase (NP) liquid chromatography is one of the most effective methods for separating isomers with sensitive structural features, including xanthophyll isomers. In this work, reverse‐phase (RP) and NP liquid chromatography (LC), with silica gel and diol phase, respectively, were evaluated for the separation of xanthophyll isomers. The results showed that RP LC with monomeric C18 phase not only poorly separate all xanthophyll isomers in egg yolk but also requires additional sample preparation to eliminate triacylglycerols in egg yolk. The diol phase of NP‐LC provided the highest efficiency for separating lutein, zeaxanthin, and their cis‐isomers with isocratic separation using mobile phases consisting of n‐hexane and polar modifiers (such as acetone, methyl tert‐butyl ether, or ethyl acetate). To determine the xanthophyll content, peak areas from LC and total absorbance from spectrophotometry measurements were used. The approach was applied to analyze the xanthophylls of nine commercial egg samples. The results revealed that five out of nine analyzed samples contained a high level of canthaxanthin, which contributes to color enhancement but not to prevent age‐related macular degeneration. Together, it shows that NP LC with diol phase combined with spectrophotometry is a powerful tool to monitor xanthophylls in eggs. [ABSTRACT FROM AUTHOR]

Canthaxanthin is a naturally occurring ketocarotenoid pigment present in plants, algae, bacteria and some fungi. In addition to its coloring role, canthaxanthin has an excellent antioxidant activity, thus having additional market demands in the feed, food, cosmetic and pharmaceutical industries. Canthaxanthin can be directly isolated from its natural source or produced by chemical synthesis, but these strategies either result in low yields, or use hazardous solvents, respectively. Therefore, the biosynthesis of canthaxanthin using microbial cell factories is becoming an advantageous alternative. Furthermore, microbial synthesis represents an economic and sustainable approach as it enables the use of agriculture and industrial wastes as substrates. In this work, the extraction, recovery and purification of canthaxanthin from modified yeasts using food grade solvents and up-scalable methodologies was studied. The resulting canthaxanthin-enriched extract was characterized (UV-Vis, PXRD and SEM) and quantified (HPLC), resulting in a canthaxanthin purity of 43.7 % (w/w). [ABSTRACT FROM AUTHOR]

ABSTRACT: This study was conducted to evaluate the effects of common canthaxanthin (CC) or microencapsulated canthaxanthin (MC) combined with apo-ester (AE) on productive performance, egg yolk color and antioxidant capacity in laying hens. A total of 270 Hyline Brown laying hens at 56 wk of age were allocated to 3 groups with 6 replicates, and fed a wheat-soybean meal basal diet or the same diet supplemented with CC+AE or MC+AE at 5 mg/kg feed for each supplement. The productive performance was not affected by dietary treatments. The 2 test groups had higher (P < 0.05) yolk color score in fresh eggs than the control group, but the yolk color score of CC+AE group significantly declined (P < 0.05) with time, and a slight decline was also observed in the MC+AE group at 36 d. The MC+AE group had higher (P < 0.05) yolk color score of fried and boiled eggs than the other 2 groups. Higher (P < 0.05) feed canthaxanthin concentration was found in the MC+AE group at the end of experiment, which also had higher yolk canthaxanthin concentration in fresh eggs at 24 and 36 d as well as in fried, boiled and stored (4°C and 25°C) eggs. The 2 test groups had higher (P < 0.05) total antioxidant capacity in serum than the control group, and lower (P < 0.05) MDA content was observed in the MC+AE group. The mRNA level of cluster determinant 36 in jejunum was increased by the 2 test groups, and the same increase was also found in liver only in the MC+AE group. In conclusion, MC was more efficient in promoting yolk color and antioxidant capacity than CC when combined with AE.

Carotenoids tend to form supramolecular aggregates via non‐covalent interactions where the chirality of individual molecules is amplified to the macroscopic level. We show that this can also be achieved for non‐chiral carotenoid monomers interacting with polysaccharides. The chirality induction in canthaxanthin (CAX), caused by heparin (HP) and hyaluronic acid (HA), was monitored by chiroptical spectroscopy. Electronic circular dichroism (ECD) and Raman optical activity (ROA) spectra indicated the presence of multiple carotenoid formations, such as H‐ and J‐type aggregates. This is consistent with molecular dynamics (MD) and density functional theory (DFT) simulations of the supramolecular structures and their spectroscopic response. [ABSTRACT FROM AUTHOR]

Brine shrimp (Artemia), rich in carotenoids, are widely used in intensive aquaculture to supplement nutrients and enhance the coloration of farmed organisms. This study investigates the growth, reproduction, and carotenoid accumulation in Artemia sinica under varying salinity and temperature conditions. The results showed that temperature and salinity displayed significant interactions with survival, body length, and carotenoid accumulation in the body. The optimal survival and growth conditions of A. sinica (Bohai Sea Gulf) were a temperature range of 25–30 °C and a salinity range of 30–50‰. High temperatures accelerated growth and sexual maturity at the expense of survival rates, while temperatures below 20 °C prevented ovigerous development. Extreme salinity levels negatively affected survival and growth, though high salinity promoted sexual maturity. Carotenoids in A. sinica mainly accumulate as echinenone and canthaxanthin form. Carotenoid accumulation decreased with increased temperature and salinity, and the temperature effect decreased with rising salinity. A. sinica cultivated at a salinity of 10‰ and a temperature of 25 °C exhibits the highest carotenoid content. Transcriptomic analysis revealed that high temperatures primarily affected genes related to stress response and metabolism, while high-salinity regulated genes associated with ion balance and signaling pathways. These findings provide a theoretical basis for enhancing Artemia sinica aquaculture and optimizing cultivation conditions, offering novel insights into nutritional and environmental impacts on brine shrimp biology.

Carotenoids belong to one of the most common classes of biological pigments. They are observed in either free form (dissolved in hydrophobic media) or as stoichiometric complexes with protein (carotenoproteins). An interaction between a carotenoid and a protein environment is determined mainly by the molecular conformation and dynamic behavior of a cofactor pigment. In this study, using molecular modeling methods, we have analyzed the whole set of alternative conformational states of cyclic side groups of carotenoids and evaluated the energy effects of their interaction with the conjugated backbone chain. The performed theoretical study resulted in the energy-sorted catalogue of alternative conformational states for biogenic cyclic carotenoids and their optical isomers. Conformational states described in this study can be used for a correct selection of initial conditions for the molecular modeling of carotenoproteins. [ABSTRACT FROM AUTHOR]

Canthaxanthin is an important antioxidant with wide application prospects, and β-carotene ketolase is the key enzyme involved in the biosynthesis of canthaxanthin. However, the challenge for the soluble expression of β-carotene ketolase is that it hinders the large-scale production of carotenoids such as canthaxanthin and astaxanthin. Hence, this study employed several strategies aiming to improve the soluble expression of β-carotene ketolase and its activity, including selecting optimal expression vectors, screening induction temperatures, adding soluble expression tags, and adding a molecular chaperone. Results showed that all these strategies can improve the soluble expression and activity of β-carotene ketolase in Escherichia coli. In particular, the production of soluble β-carotene ketolase was increased 8 times, with a commercial molecular chaperon of pG-KJE8, leading to a 1.16-fold enhancement in the canthaxanthin production from β-carotene. Interestingly, pG-KJE8 could also enhance the soluble expression of β-carotene ketolase derived from eukaryotic microalgae. Further research showed that the production of canthaxanthin and echinenone was significantly improved by as many as 30.77 times when the pG-KJE8 was added, indicating the molecular chaperone performed differently among different β-carotene ketolase. This study not only laid a foundation for further research on the improvement of β-carotene ketolase activity but also provided new ideas for the improvement of carotenoid production. [ABSTRACT FROM AUTHOR]

Canthaxanthin is an orange-red keto-carotenoid that occurs naturally and is also manufactured by synthetic methods for regular applications. In nature, canthaxanthin mainly exists in microbes such as different bacterial species, fungi, and algae, as well as in animals such as crustaceans, certain fishes, and birds. However, the amount of canthaxanthin produced in these organisms varies significantly. Additionally, the compound can be generated from genetically modified organisms using genetic engineering techniques Canthaxanthin finds extensive application as an additive in animal feed, in the pharmaceutical industry, as a coloring agent for various food products, and in cosmetics. It has powerful antioxidant properties and plays a role in lipid metabolism, neuroprotection, and immunomodulation. This article gives an extensive insight into the structure and methods of synthesis of canthaxanthin along with its various newly discovered sources identified so far. The significant applications of canthaxanthin, particularly its role in pharmaceuticals, are critically evaluated. Furthermore, the article discusses future aspects and challenges associated with canthaxanthin production and regulation.

Simple Summary: Huaixiang chicken is a famous local broiler in China. It has excellent meat quality, but its disadvantage is a low laying rate. At present, improving the laying rate of poultry via nutritional regulation has attracted the extensive attention of researchers. Canthaxanthin(CX) is a ketocarotenoid, which widely exists in marine animals, algae, and a few terrestrial plants. It has been used in poultry production. In this study, dietary CX supplementation is found to increase laying rates, promote ovulation and maintain reproductive hormone levels by increasing serum and ovarian antioxidant levels. It is suggested that CX can be used to improve the laying rate of Huaixiang broiler breeders. Canthaxanthin(CX) is a ketocarotenoid, which is widely used in poultry production as a lipophilic antioxidant. Huaixiang chickens are a local breed in China famous for their excellent meat quality; improving their laying rate via nutritional regulation has attracted extensive attention. The aim of this study was to evaluate the effects of dietary CX on the laying rate and follicular development in Huaixiang hens. A total of 180 Huaixiang hens were randomly divided into five groups with six replicates, and six chickens per replication. The control group (CON) were fed a basal diet, and the treatment group (NT) were fed a basal diet supplemented with 4, 6, 8 and 10 mg/kg CX. All chickens were 26 weeks old, living at an average environmental temperature of 25 ± 2 °C with a relative humidity of 65–75%. The results showed that supplementing the CX improved the laying rate and large white follicles (LWF) number (p < 0.05) and increased the concentration of reproductive hormones (LH, FSH, E2 and Prog) (p < 0.05), and the basal diet supplemented with 6 mg/kg CX worked best. Moreover, CX could increase the activities of antioxidant enzymes SOD and GSH-Px (p < 0.05) and reduce the content of the lipid peroxidation product MDA in Huaixiang chickens (p < 0.05); again, 6 mg/kg CX was best. In conclusion, dietary CX had positive effects on the laying rate, ovarian structure, reproductive hormone secretion, follicle development, and the antioxidant capacity of Huaixiang hens, and 6 mg/kg CX was recommended to be added to the diet of Huaixiang chickens. [ABSTRACT FROM AUTHOR]

The research and development of carotenoid production has a long history, and interest in this group of pigments has not decreased to this day. Six existing carotenoids are considered industrially important: astaxanthin, β-carotene, lutein, zeaxanthin, canthaxanthin, and lycopene. These carotenoids have a wide range of applications and are used as additives in food and beverages, feed, nutraceuticals, pharmaceuticals, and cosmetics products due to their bioactive and pigmentation properties. Currently, the global pigment market is dominated by chemically synthesized carotenoids. Carotenoids derived from natural sources such as plants and microorganisms are not as popular or widespread. Currently, the market of natural carotenoids is mainly represented by microalgae Haematococcus pluvialis, Dunaliella salina, Botryococcus braunii, fungus Blakeslea trispora, yeast Phaffia rhodozyma and bacteria Paracoccus carotinifaciens. These microorganisms produce astaxanthin, β-carotene, canthaxanthin, and lycopene. Several yeast and bacteria species from Rhodotorula, Sporobolomyces, Sporidiobolus, Gordonia, and Dietzia genus can potentially become sources of carotenoids on an industrial scale, but available technologies still need improving. This paper reviews strategies for increasing the competitiveness of fungal and bacterial carotenoid production. Strategies such as selecting carotenogenic strains, using low-cost substrates, stimulating the synthesis of carotenoids by adding trace elements, TCA intermediates, NaCl, H2O2, light irradiation, and optimization of fermentation conditions such as pH, temperature and aeration are considered.

Our analysis of the X-ray crystal structure of canthaxanthin (CAN) showed that its ketolated β-ionone rings can adopt two energetically equal, but structurally distinct puckers. Quantum chemistry calculations revealed that the potential energy surface of the β-ionone ring rotation over the plane of the conjugated π-system in carotenoids depends on the pucker state of the β-ring. Considering different pucker states and β-ionone ring rotation, we found six separate local minima on the potential energy surface defining the geometry of the keto-β-ionone ring—two cis and one trans orientation for each of two pucker states. We observed a small difference in energy and no difference in relative orientation for the cis-minima, but a pronounced difference for the position of trans-minimum in alternative pucker configurations. An energetic advantage of β-ionone ring rotation from a specific pucker type can reach up to 8 kJ/mol ( 669 cm - 1 ). In addition, we performed the simulation of linear absorption of CAN in hexane and in a unit cell of the CAN crystal. The electronic energies of S 0 → S 2 transition were estimated both for the CAN monomer and in the CAN crystal. The difference between them reached 690 cm - 1 , which roughly corresponds to the energy gap between A and B pucker states predicted by theoretical estimations. Finally, we have discussed the importance of such effects for biological systems whose local environment determines conformational mobility, and optical/functional characteristics of carotenoid. [ABSTRACT FROM AUTHOR]

Background: The number of older people in the world is increasing year by year; studies have shown that more than 90% of cardiovascular disease occurs in the older people population, indicating that aging is one of the major risks involved in the development of cardiovascular disease. Therefore, retarding the development of cardiac aging is an important strategy to prevent aging-related cardiovascular diseases. Methods: In the current study, we examined the anti-cardiovascular aging potential of canthaxanthin in vitro and in vivo experiments. For this, a model of cardiomyocyte senescence induced by D-galactose was established, which was used to investigate the canthaxanthin’s effect on cardiac premature aging. Results: We found that canthaxanthin obviously mitigated the cardiomyocyte senescence in vitro. Further mechanistic studies revealed that canthaxanthin seems to alleviate cardiomyocyte senescence by regulating the autophagy process. Furthermore, the effects of canthaxanthin on cardiovascular senescence were further evaluated. We also observed that canthaxanthin mitigated cardiac aging and fibrosis in the aged mice model. Conclusions: To sum up, the current work showed that canthaxanthin could obviously alleviate cardiac premature aging, indicating that canthaxanthin could be used as a biologically active molecule for the treatment of cardiac aging and fibrosis.

Canthaxanthin is an important antioxidant with wide application prospects, and β-carotene ketolase is the key enzyme involved in the biosynthesis of canthaxanthin. However, the challenge for the soluble expression of β-carotene ketolase is that it hinders the large-scale production of carotenoids such as canthaxanthin and astaxanthin. Hence, this study employed several strategies aiming to improve the soluble expression of β-carotene ketolase and its activity, including selecting optimal expression vectors, screening induction temperatures, adding soluble expression tags, and adding a molecular chaperone. Results showed that all these strategies can improve the soluble expression and activity of β-carotene ketolase in Escherichia coli. In particular, the production of soluble β-carotene ketolase was increased 8 times, with a commercial molecular chaperon of pG-KJE8, leading to a 1.16-fold enhancement in the canthaxanthin production from β-carotene. Interestingly, pG-KJE8 could also enhance the soluble expression of β-carotene ketolase derived from eukaryotic microalgae. Further research showed that the production of canthaxanthin and echinenone was significantly improved by as many as 30.77 times when the pG-KJE8 was added, indicating the molecular chaperone performed differently among different β-carotene ketolase. This study not only laid a foundation for further research on the improvement of β-carotene ketolase activity but also provided new ideas for the improvement of carotenoid production.

This study examined the impacts of dietary spirulina (SP) and canthaxanthin (CX) supplementation to laying hens on reproductive performance and cock's semen quality evaluation. Three hundred and sixty of indigenous Sinai chickens (300 hens + 60 cocks), 48‐weeks‐old, were randomly divided into five treatments; a control and four supplemented (0.6 g SP mg/kg, 0.8 g SP mg/kg, 6 mg CX/kg diet, and 8 mg CX/kg diet) with six replications of 10 females and 1 male per treatment for laying trial and 1 male for semen evaluation. The animals were fed with experimental diets for 12 weeks. Supplementing 6 mg CX/kg diet led to an increase in the final body weight and egg production traits, while 8 mg CX/kg diet resulted in an improving feed conversion ratio. Supplementation of 0.6 g SP mg/kg or 6.0 mg CX/kg diet resulted in the highest egg production. The heaviest egg weight and egg mass were induced by 0.8 g SP mg/kg. Eggs laid from hens fed 0.6 g SP/kg diet had a higher concentration of cholesterol than those fed 0.8 g SP/kg and those fed 6.0 and 8.0 mg CX/kg. Cocks fed 6 mg CX/kg and those fed 0.8 g SP/kg diet had the greatest sperm concentration. The supplementation of 0.8 g SP mg/kg diet or both 6 and 8 mg CX/kg diet enhanced hatchability. So, dietary spirulina (0.8 mg/kg) and canthaxanthin (6 mg/kg) supplementation to Sinai laying hens and cocks could be used to improve productive and reproductive and performance. [ABSTRACT FROM AUTHOR]

Aurantiochytrium limacinum is a heterotrophic eukaryotic microorganism that can accumulate high levels of commercial products such as astaxanthin and docosahexaenoic acid. Due to its rapid growth and relatively simple extraction method, A.limacinum is considered a promising astaxanthin resource to replace the conventional microalgal production. However, the astaxanthin biosynthetic process in A.limacinum remains incompletely understood, especially in those catalysed by β-carotene hydroxylase (CrtZ) and ketolase. In this study, we overexpressed a crtZ candidate gene to increase astaxanthin production and expand our understanding of the conversion from beta-carotene to astaxanthin. The resultant transformant AlcrtZ#10 cultivated for 5 days showed a significant increase in astaxanthin production per culture (2.8-fold) and per cell (4.5-fold) compared with that of the wild-type strain. Strikingly, longer light exposure increased astaxanthin production and decreased the beta-carotene content in the wild-type strain, suggesting that light exposure duration is important for astaxanthin production in A.limacinum. Among several predicted intermediates, furthermore, the cantaxanthin produced from β-carotene by ketolase activity were enhanced in the transformant AlcrtZ#10. Although the further investigation is needed, this result suggested that the main route of astaxanthin was via cantaxanthin. Thus, our findings will be valuable not only for its application, but also for understanding the astaxanthin biosynthetic process in A.limacinum. [ABSTRACT FROM AUTHOR]

Background: Vascular endothelial dysfunction is an early phenotype of aging-related vascular dysfunction. Delaying vascular aging and preventing cardiovascular disease are major public health problems that urgently need to be solved. Scientists have studied various drugs to prevent the occurrence and progress of cardiovascular disease, but progress has been slow. Here, the antisenescence and anti-endothelial damage of canthaxanthin (CX, which is an active molecule from food) has been studied. Methods: This study was performed by adding CX to a model of cell senescence and oxidative damage induced by hydrogen peroxide. Cellular senescence markers (e.g., p16, p21, and p53) and oxidative damage markers (e.g., reactive oxygen species, nitric oxide, malondialdehyde, superoxide dismutase) were evaluated by the enzyme-linked immunosorbent assay, laser scanning confocal microscopy, and Western blotting. Results: We found that CX downregulated the expression level of senescence-associated molecules, and significantly reduced the oxidative damage of vascular endothelial cells. These observations showed that CX effectively alleviated the senescence of vascular endothelial cells. Furthermore, CX treatment reduced the expression levels of interleukin-6 (IL-6), tumor necrosis factor alpha, and IL-1β. Finally, in vivo, CX significantly alleviated vascular senescence. Conclusions: The current study shows that CX has potential application value for treating vascular aging or endothelial cell senescence.

Canthaxanthin(CX) is a ketocarotenoid, which is widely used in poultry production as a lipophilic antioxidant. Huaixiang chickens are a local breed in China famous for their excellent meat quality; improving their laying rate via nutritional regulation has attracted extensive attention. The aim of this study was to evaluate the effects of dietary CX on the laying rate and follicular development in Huaixiang hens. A total of 180 Huaixiang hens were randomly divided into five groups with six replicates, and six chickens per replication. The control group (CON) were fed a basal diet, and the treatment group (NT) were fed a basal diet supplemented with 4, 6, 8 and 10 mg/kg CX. All chickens were 26 weeks old, living at an average environmental temperature of 25 ± 2 °C with a relative humidity of 65–75%. The results showed that supplementing the CX improved the laying rate and large white follicles (LWF) number (p < 0.05) and increased the concentration of reproductive hormones (LH, FSH, E2 and Prog) (p < 0.05), and the basal diet supplemented with 6 mg/kg CX worked best. Moreover, CX could increase the activities of antioxidant enzymes SOD and GSH-Px (p < 0.05) and reduce the content of the lipid peroxidation product MDA in Huaixiang chickens (p < 0.05); again, 6 mg/kg CX was best. In conclusion, dietary CX had positive effects on the laying rate, ovarian structure, reproductive hormone secretion, follicle development, and the antioxidant capacity of Huaixiang hens, and 6 mg/kg CX was recommended to be added to the diet of Huaixiang chickens.

Purple nonsulfur bacteria (PNSB) were investigated for their carotenoid production and anti‐vibrio activity against acute hepatopancreatic necrosis disease (AHPND)‐causing Vibrio parahaemolyticus. To test carotenoid production, selected strains were cultivated in basic isolation medium (BIM), glutamate acetate medium, G5 medium and artificial acetic acid wastewater (AAW) medium. From 144 PNSB, Rhodopseudomonas palustris KTSSG46 was selected to produce carotenoids under microaerobic light conditions in BIM. When the culture medium was optimized, strain KTSSG46 grown in BIM modified with l‐glutamate at 1 g/L more effectively inhibited AHPND‐causing V. parahaemolyticus strains than standard BIM with 1 g/L (NH4)2SO4. BIM was further modified with 1.23 g/L MgSO4·7H2O and carotenoid production increased 40.22%. Carotenoid production at day 2 by strain KTSSG46 grown in BIM modified with l‐glutamate at 1 and 1.23 g/L MgSO4·7H2O was the same as production in BIM modified with monosodium glutamate (MSG). Culture supernatants from all BIM formulations showed similar activity against the resistant AHPND strain SR2. Based on high‐performance liquid chromatography, carotenoids of strain KTSSG46 might be canthaxanthin. Grown in BIM modified with MSG, strain KTSSG46 could produce inexpensive carotenoids and release anti‐vibrio compounds that, applied as shrimp feed additive, would prevent AHPND strains. [ABSTRACT FROM AUTHOR]

Microbial rhodopsin is a transmembrane protein that functions with a chromophore and is regulated by light. In nature, regulation through the retinal chromophore plays an important role in physiological phenomena. However, living organisms in soil, sea, and freshwater synthesize carotenoids preferentially over retinal in the biosynthetic pathway. Evolution has extended the energy conversion photosystem with additional pigments that act as antennae. Previously, Gloeobacter rhodopsin and xanthorhodopsin have been reported to form secondary chromophores with carotenoids. In this study, we report that a thermophilic rhodopsin (TR) and Tara76 rhodopsin, the latter of which is classified as a blue light‐absorbing proteorhodopsin, can form secondary chromophores with canthaxanthin (CAN). Tara76 rhodopsin and TR were found to exhibit high thermal stabilities and photophysical properties following their interaction with CAN. Isothermal titration calorimetry analysis, spectral shift measurements, and exciton analysis were used to examine the interactions of these rhodopsins with CAN. It was found that these interactions increased the stability toward temperature and pH through highly efficient chromophore formation, in addition to rapidly recruiting the retinal at a rate approximately twice as high as that obtained in the absence of CAN. [ABSTRACT FROM AUTHOR]

Carotenoids are among the most widely distributed pigments in nature with broad application options in pharmacology, cosmetics and food industries. For commercial-scale production using microalgae, however, it is crucial to find the best performing strains regarding growth and yields of the products of interest. As terrestrial microalgae present the ability to quickly adapt to changing or unfavorable environmental conditions through cell-specific defense mechanisms, they constitute highly promising candidates. The present study thus aimed to investigate the potential of five terrestrial microalgal strains to increasingly produce the carotenoids β-carotene, canthaxanthin and astaxanthin when being exposed to UV-A stress. Light stress experiments were performed using a novel irradiation system based on UV-LED technology. Microalgal cultures were treated with UV-A radiation to stimulate carotenogenesis and the time-dependent effects were investigated by high-performance liquid chromatography analysis. The potential of the microalgae to enhance de novo biosynthesis of the targeted metabolites under the influence of UV-A light could be confirmed by significantly increased yields of canthaxanthin in four out of five strains and by a significantly enhanced β-carotene concentration in at least one strain during 72 h of investigation. Overall, the results provided evidence that UV-A light stress can be effective in rapidly inducing carotenogenesis in terrestrial microalgae and thus harbors vast potential for further exploitation regarding large-scale carotenoid production. [ABSTRACT FROM AUTHOR]

The carotenogenic thraustochytrid Thraustochytrium sp. RT2316-16 was grown in batch and repeated-batch cultures using different feeds containing glucose, or glycerol, and yeast extract, for the production of lipids, phospholipids and carotenoids. RT2316-16 produced canthaxanthin, astaxanthin and β-carotene. The effects of biotin, ascorbic acid, light and temperature were evaluated in some of the experiments. In 2-day-old batch cultures, the combined mass percentage of eicosapentaenoic acid and docosahexaenoic acid in total lipids was between 16.5% (glycerol-based medium in the dark; biomass concentration = 4.2 ± 1.1 g L−1) and 42.6% (glucose-based medium under light; biomass concentration = 3.3 ± 0.1 g L−1), decreasing to 3.8% and 6.1%, respectively, after day 4. In repeated-batch cultures, the total lipids in the biomass increased after glucose or glycerol was fed alone, whereas the total carotenoids (168 ± 7 μg g−1 dry weight (DW)) and phospholipids in the biomass increased after feeding with yeast extract. The biomass with the highest content of phospholipids (28.7 ± 4.3 mg g−1 DW) was obtained using a feed medium formulated with glycerol, yeast extract and ascorbic acid. Glycerol was the best carbon source for the production of a biomass enriched with total lipids (467 ± 45 mg g−1 DW). The composition of carotenoids depended strongly on the composition of the feed. Repeated-batch cultures fed with yeast extract contained canthaxanthin as the main carotenoid, whereas in the cultures fed only with glucose, the biomass contained mainly β-carotene. [ABSTRACT FROM AUTHOR]

In this study, we studied the levels of both of the main pigments in Salmonidae—astaxanthin (Ax) and canthaxanthin (Cx)—accumulated in the liver, female gonads, and male gonads of rainbow trout (Oncorhynchus mykiss) reared in water containing the fungicide mancozeb (MZ) in concentration levels permitted by European legislation. Experimental fish were divided into three groups: the first was a control group, the second was fed with market feed (containing Ax and Cx), and the third was fed with market feed (containing Ax and Cx) and reared in environmental water containing permissible MZ levels. The diet preparation followed the manufacturer's recommendations. The accumulated pigment quantities were measured using an HPLC-PDA method after selective extraction: Ax ranged from 2.490 ± 0.247 mg/kg (female gonads, second group) to 0.176 ± 0.007 mg/kg (liver, control group), and Cx—from 2.406 ± 0.166 mg/kg (female gonads, second group) to 0.103 ± 0.010 mg/kg (liver, control group). The pattern of the accumulation of both pigments in the three organs in the specimens of the three groups was sustainable: the amount of Ax was always greater than that of Cx, and the correlation between their concentrations was very high. The pigments were accumulated most intensively in the female gonads, followed by the male gonads and the liver. This trend was confirmed for all three experimental groups. However, the differences in the last third group were very small, and the levels of the xanthophylls accumulated were the lowest. A particular cause of the latter findings was the ongoing detoxification reactions and the disposal of MZ, in which Ax and Cx were involved as antioxidants. [ABSTRACT FROM AUTHOR]

Introduction. The bacterium strain Paracoccus carotinifaciens VTP20181 isolated in Vietnam produces canthaxanthin, a carotenoid widely used in the food and pharmaceutical industries. The aim of this work was to determine optimal parameters for canthaxanthin extraction from fermented biomass of P. carotinifaciens VTP20181. Study objects and methods. First, a series of single factor investigations were carried out in regard to maximal carotenoid content in the biomass extract obtained by using ultrasonic waves. Four parameters of the extraction process, such as extraction temperature, solvent/material ratio, extraction time, and ultrasonic output power, were studied. The obtained results were then optimized by using Response Surface Methodology (RSM) and Box-Behnken experimental design. Results and discussion. The optimal technological parameters of the extraction process included extraction temperature of 35°C, solvent/material ratio of 9.5:1 (v/w), extraction time of 90 min, and ultrasonic output power of 145 W. Under optimal conditions, canthaxanthin and total carotenoid contents were determined as 14.95 ± 0.12 and 18.21 ± 0.11 mg/g respectively, which were compatible with theoretical calculations ‒ 15.074 and 18.263 mg/g, respectively. Conclusion. Current results confirmed that the strain of halophilic P. carotinifaciens VTP20181 is a potential source for canthaxanthin biosynthesis.

Carotenoids perform multifaceted roles in life ranging from coloration over light harvesting to photoprotection. The Orange Carotenoid Protein (OCP), a light-driven photoswitch involved in cyanobacterial photoprotection, accommodates a ketocarotenoid vital for its function. OCP extracts its ketocarotenoid directly from membranes, or accepts it from homologs of its C-terminal domain (CTDH). The CTDH from Anabaena (AnaCTDH) was shown to be important for carotenoid transfer and delivery from/to membranes. The C-terminal tail of AnaCTDH is a critical structural element likely serving as a gatekeeper and facilitator of carotenoid uptake from membranes. We investigated the impact of amino acid substitutions within the AnaCTDH-CTT on echinenone and canthaxanthin uptake from DOPC and DMPG liposomes. The transfer rate was uniformly reduced for substitutions of Arg-137 and Arg-138 to Gln or Ala, and depended on the lipid type, indicating a weaker interaction particularly with the lipid head group. Our results further suggest that Glu-132 has a membrane-anchoring effect on the PC lipids, specifically at the choline motif as inferred from the strongly different effects of the CTT variants on the extraction from the two liposome types. The substitution of Pro-130 by Gly suggests that the CTT is perpendicular to both the membrane and the main AnaCTDH protein during carotenoid extraction. Finally, the simultaneous mutation of Leu-133, Leu-134 and Leu-136 for alanines showed that the hydrophobicity of the CTT is crucial for carotenoid uptake. Since some substitutions accelerated carotenoid transfer into AnaCTDH while others slowed it down, carotenoprotein properties can be engineered toward the requirements of applications. • A CTDH homolog from S. thermophilus , which lacks a CTT, does not bind ketocarotenoids. • CTT mutations differentially affect xanthophyll uptake into the CTDH protein from Anabaena. • Mutations of R137 and R138 retarded carotenoid transfer into AnaCTDH. • Mutation of E132 exhibits differences depending on the type of liposome and suggests a membrane anchoring effect. • Mutation P130G sped up while triple-leucine mutation slowed down carotenoid uptake. • Carotenoid transfer properties can be adjusted for particular biotechnological applications. [ABSTRACT FROM AUTHOR]

ABSTRACT: Canthaxanthin is widely used as a feed additive to improve skin and yolk color in poultry. It is insoluble in water and sensitive to oxidation, so commercial canthaxanthin is often microencapsulated with wall materials to improve its solubility and stability. The objective of this study was to evaluate the effects of canthaxanthin microencapsulation on yolk color and canthaxanthin deposition in egg yolk of laying hens. A total of 288 Hyline Brown laying hens (48 wk of age) were allocated to 4 groups with 6 replicates of 12 hens each, and fed a basal diet or the basal diet supplemented with 5 mg/kg canthaxanthin microencapsulated with modified starch (CMMS), gelatin (CMG), and sodium lignosulfonate (CMSL), respectively. Canthaxanthin supplementation did not affect laying performance of hens, but improved (P < 0.05) yolk color of fresh, fried, boiled, and stored (4 and 25°C) eggs. The improvement of yolk color of fresh eggs was greatest in the CMSL group and least in the CMG group (P < 0.05). Both CMMS and CMSL resulted in higher (P < 0.05) yolk canthaxanthin concentration than CMG. The CMSL resulted in higher (P < 0.05) yolk color score of fried eggs than CMMS and CMG and higher (P < 0.05) yolk color score of boiled eggs than CMG, but no difference was observed in stored eggs among three canthaxanthin groups. In conclusion, CMMS and CMSL were more effective in yolk pigmentation than CMG, and CMSL was slightly better than CMMS.

Considering the importance of microalgae as a promising feedstock for the production of both low- and high-value products, such as lipids and pigments, it is desirable to isolate strains which simultaneously accumulate these two types of products and grow in various conditions in order to widen their biotechnological applicability. A novel freshwater strain from the genus Coelastrella was isolated in Belgium. Compared to other Coelastrella species, the isolate presented rapid growth in phototrophy, dividing 3.5 times per day at a light intensity of 400 µmol·m−2·s−1 and 5% CO2. In addition, nitrogen depletion was associated with the accumulation of astaxanthin, canthaxanthin, and fatty acids, which reached ~30% of dry weight, and a majority of SFAs and MUFAs, which are good precursors for biodiesel. This strain also accumulated astaxanthin and canthaxanthin in heterotrophy. Although the content was very low in this latter condition, it is an interesting feature considering the biotechnological potential of the microalgal heterotrophic growth. Thus, due to its rapid growth in the light, its carotenogenesis, and its fatty acids characteristics, the newly identified Coelastrella strain could be considered as a potential candidate for biorefinery purposes of both low- and high-values products. [ABSTRACT FROM AUTHOR]

A novel strain of Coelastrella terrestris (Chlorophyta) was collected from red mucilage in a glacier foreland in Iceland. Its morphology showed characteristic single, ellipsoidal cells with apical wart-like wall thickenings. Physiological characterization revealed the presence of the rare keto-carotenoid adonixanthin, as well as high levels of unsaturated fatty acids of up to 85%. Initial screening experiments with different carbon sources for accelerated mixotrophic biomass growth were done. Consequently, a scale up to 1.25 L stirred photobioreactor cultivations yielded a maximum of 1.96 mg·L−1 adonixanthin in free and esterified forms. It could be shown that supplementing acetate to the medium increased the volumetric productivity after entering the nitrogen limitation phase compared to autotrophic control cultures. This study describes a promising way of biotechnological adonixanthin production using Coelastrella terrestris. [ABSTRACT FROM AUTHOR]

Antioxidants are used to minimize oxidative stress during liquid semen storage. The main aim of current study was to elucidate effect of supplementing melatonin and canthaxanthin in Tris‐based extender could enhance seminal quality of ram at 4°C up to 72 h. A total of 48 ejaculates were collected from breeding Magra rams (n = 8) and were preliminarily subjected for various macroscopic and microscopic semen evaluation tests. These ejaculates were pooled and divided into three equal aliquots. Two aliquots were diluted (1:10) using extender encompassing final concentration of 1mM melatonin and 25 µM canthaxanthin and stored at 4°C. Third aliquot with extender only was kept as control. Structural and functional seminal changes were observed at different time points of preservation. Results revealed that mean values for progressive sperm motility, viability and total antioxidant capacity were significantly higher (p < 0.05) in melatonin group while hypo‐osmotic swelling test was significantly (p < 0.05) higher in canthaxanthin group. Total sperm abnormalities and malondialdehyde levels were significantly (p < 0.05) lower in both treatment groups indicating their antioxidant efficacy in protection of spermatozoa from oxidative stress. Results of study indicated that supplementation of these antioxidants to ram semen could be used to enhance storage life of liquid semen at 4°C up to 72 h. [ABSTRACT FROM AUTHOR]

Over the past decades, nutraceuticals have attracted considerable interest because of their potential nutritional, safety and therapeutic effects. Carotenoid molecules are potent nutraceuticals with an attractive colour and have been shown to play crucial roles in the immune system and susceptibility of organisms to certain diseases. Reactive oxygen species (ROS) are considered to be a major threat to cellular components and lead to protein oxidation, lipid peroxidation and DNA damage. In the present study, canthaxanthin (CX), an orange-red keto-carotenoid, was extracted from Dietzia maris NITD. Carbonyl content measurement showed that the presence of CX can prevent protein oxidation in D. maris NITD. The inhibition of protein oxidation in vitro revealed a high correlation coefficient of the extracted CX with positive controls. Both the linoleic acid model (IC50 = 932.48 μg/ml) and the goat liver model experiments showed that CX can also inhibit lipid peroxidation in vitro. CX from D. maris NITD was also proved to be effective in maintaining the observable intactness of a model DNA (pBR322). The present study indicated that bacterial CX can be a useful bioactive compound to prevent oxidative damage incurred by cellular macromolecules in terms of pharmaceutical and nutraceutical aspects.

Unconventional oleaginous yeast Yarrowia lipolytica has gained widespread applications as a microbial cell factory for synthesizing various chemicals and natural products. The construction of efficient cell factories requires intricate metabolic engineering. However, multi-gene expression in Y. lipolytica is labor-intensive. To facilitate multi-gene expression, we developed the polycistronic expression tool using 2A peptides. We first compared different 2A peptides in Y. lipolytica and identified two 2A peptides with high cleavage efficiency: P2A and ERBV-1. The effect of 2A peptides on the expression level of upstream and downstream genes was then determined. Ultimately, we applied the identified 2A peptides to express four genes in canthaxanthin biosynthetic pathway within one expression cassette for canthaxanthin production. This study enriches the multi-gene expression tools of Y. lipolytica , which will facilitate the cell factory construction of Y. lipolytica ., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

This study was conducted to evaluate the effects of common canthaxanthin (CC) or microencapsulated canthaxanthin (MC) combined with apo-ester (AE) on productive performance, egg yolk color and antioxidant capacity in laying hens. A total of 270 Hyline Brown laying hens at 56 wk of age were allocated to 3 groups with 6 replicates, and fed a wheat-soybean meal basal diet or the same diet supplemented with CC+AE or MC+AE at 5 mg/kg feed for each supplement. The productive performance was not affected by dietary treatments. The 2 test groups had higher (P < 0.05) yolk color score in fresh eggs than the control group, but the yolk color score of CC+AE group significantly declined (P < 0.05) with time, and a slight decline was also observed in the MC+AE group at 36 d. The MC+AE group had higher (P < 0.05) yolk color score of fried and boiled eggs than the other 2 groups. Higher (P < 0.05) feed canthaxanthin concentration was found in the MC+AE group at the end of experiment, which also had higher yolk canthaxanthin concentration in fresh eggs at 24 and 36 d as well as in fried, boiled and stored (4°C and 25°C) eggs. The 2 test groups had higher (P < 0.05) total antioxidant capacity in serum than the control group, and lower (P < 0.05) MDA content was observed in the MC+AE group. The mRNA level of cluster determinant 36 in jejunum was increased by the 2 test groups, and the same increase was also found in liver only in the MC+AE group. In conclusion, MC was more efficient in promoting yolk color and antioxidant capacity than CC when combined with AE., Competing Interests: DISCLOSURES We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the content of this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Definition: Carotenoids are the pigments present in plants, animals, and microorganisms which are responsible for a broad variety of colors found in nature. Their capacity as antioxidants mainly established their marketable success as health, food, and feed supplements, and cosmetics components. Currently, chemical synthesis dominates the worldwide market; however, due to the high biological value of natural carotenoids, the production scheme is moving towards microbial production as a profitable alternative. [ABSTRACT FROM AUTHOR]

The current research aims at using canthaxanthin (CAX) and betaine (BET) as nutritional additives in the diets of aged Fayoumi laying hens to improve their persistency for post-peak egg production. A total of 160 Fayoumi hens were randomly distributed into 4 dietary treatment groups from 46-54 wk of age: a group that received a basal diet without supplementations (control), and the other groups received the basal diet supplemented with canthaxanthin at 6 mg/kg (CAX), betaine at 1 g/kg (BET) or a combination of canthaxanthin and betaine (MIX), Tentatively. Parameters of productive performance, egg quality and antioxidant prank were evaluated for all treatment groups. Results indicate that CAX and BET partially improve egg quantity and quality of aged Fayoumi chickens through modulating different pathways of enzymatic and non-enzymatic antioxidant capacity. CAX and BET enhanced the egg numbers produced per hen and improved the feed conversion ratio compared to the control. In addition, CAX increased the total egg mass and the yolk color score, as well as the plasma total antioxidant capacity (TAOC) and glutathione peroxidase enzyme (GSH-Pc), while the malondialdehyde (MDA) was decreased in all supplementary groups of CAX and BET. It is concluded that dietary CAX and BET supplementation can support the productive performance of Fayoumi hens at the late phase of egg production through its protective effect against oxidative stress of aging process. This in turn can enhance the complementary role of such local or native chicken breeds to support the commercial sector of egg production especially in the rural areas. [ABSTRACT FROM AUTHOR]

In this trial, the interaction between two different light resource and different levels of two pigments was investigated in order to determine their effects on growth and reproductive performance of the ornamental fish swordtail (Xiphophorus helleri) broodstock. Fish were fed with different levels of 50, 100 and 200 mg · kg-1 of astaxanthin or canthaxanthin, under two different light conditions (natural and artificial). The obtained results were more evident in animals fed with astaxanthin in comparison to canthaxanthin. Furthermore, swordtails reared under artificial light in comparison to the natural light source showed better performance. Overall the greatest effect was for the fish treated with medium dose of astaxanthin (100 mg.kg-1), under the artificial light conditions of rearing. Results indicated the important effects of all three factors (light source, dosage and carotenoids type), with significant interactions between the carotenoid dosage with carotenoid type and light source. [ABSTRACT FROM AUTHOR]

Canthaxanthin is a reddish-orange xanthophyll with strong antioxidant activity and higher bioavailability than carotenes, primarily used in food, cosmetics, aquaculture, and pharmaceutical industries. The spiking market for natural canthaxanthin promoted researchers toward genetic engineering of heterologous hosts for canthaxanthin production. Mucor circinelloides is a dimorphic fungus that produces β-carotene as the major carotenoid and is considered as a model organism for carotenogenic studies. In this study, canthaxanthin-producing M. circinelloides strain was developed by integrating the codon-optimized β-carotene ketolase gene (bkt) of the Haematococcus pluvialis into the genome of the fungus under the control of strong promoter zrt1. First, a basic plasmid was constructed to disrupt crgA gene, a negative regulator of carotene biosynthesis resulted in substantial β-carotene production, which served as the building block for canthaxanthin by further enzymatic reaction of the ketolase enzyme. The genetically engineered strain produced a significant amount (576 ± 28 μg/g) of canthaxanthin, which is the highest amount reported in Mucor to date. Moreover, the cell dry weight of the recombinant strain was also determined, producing up to more than 9.0 g/L, after 96 h. The mRNA expression level of bkt in the overexpressing strain was analyzed by RT-qPCR, which increased by 5.3-, 4.1-, and 3-folds at 24, 48, and 72 h, respectively, compared with the control strain. The canthaxanthin-producing M. circinelloides strain obtained in this study provided a basis for further improving the biotechnological production of canthaxanthin and suggested a useful approach for the construction of more valuable carotenoids, such as astaxanthin.

Today’s global problems and challenges have given rise to a new field of interest – bioeconomics. It is strongly related to phycoprospecting, or searching for specific algal strains of commercial importance. There has been growing interest in the small algal class Eustigmatophyceae in recent years. These microscopic stramenopilic algae, which have all the advantages of microalgal cultivation, have proved to be promising commercial sources of valuable compounds (e.g. carotenoids, unsaturated fatty acids, amino acids) in aquaculture, agriculture, biofuels production, medicine, pharmaceutics, cosmetics, wastewater treatment, environmental control, etc. The present review shows the main genera and strains of commercial importance, outlines their main fields of application and some gaps in our knowledge in this aspect. Today, the great promising bioeconomical potential of these algae has generally been recognized, but in the present state of its infancy, it is far from being fully exploited.

A bacterial strain was isolated from an oil-contaminated site and on its' further characterization, exhibited the potential of synthesising metabolites and the ability to degrade crude oil. Its' morphological, biochemical and 16S rRNA analysis suggested that the bacterium belongs to Dietzia maris AURCCBT01. This strain rapidly grew in the medium supplemented with n-alkanes C14, C18, C20, C28 and C32 utilizing them as a sole carbon source and produced a maximum canthaxanthin pigment of 971.37 µg/L in the n-C14 supplemented medium and produced the lowest pigment yield of 389.48 µg/L in the n-C-32 supplemented medium. Moreover, the strain effectively degraded 91.87% of crude oil in 7 days. The emulsification activity of the strain was 25% with the highest cell surface hydrophobicity (70.26%) and it showed a decrease in surface tension, indicating that the biosurfactant production lowers the surface tension. This is the first report on the characterization of the strain, Dietzia maris AURCCBT01 and its' novelty of alkane degradation and simultaneous production of canthaxanthin pigment. [ABSTRACT FROM AUTHOR]

Aim: Nano‐biotechnologically synthesizing silver nanoparticles via canthaxanthin pigment extracted from Dietzia maris AURCCBT01 and assessing their cytotoxic therapeutic potential against human keratinocyte cell line (HaCaT) were the key objectives of this study. Methods and Results: The pigment extracted from D. maris AURCCBT01 was identified as canthaxanthin using UV‐VIS spectroscopy, FTIR, NMR (1H NMR and 13C NMR) and MS. Canthaxanthin, treated with silver nitrate solution, produced canthaxanthin‐mediated silver nanoparticles and they were characterized by UV‐VIS spectroscopy, FTIR, XRD, FESEM‐EDX and TEM‐SAED techniques. UV‐VIS spectroscopy pointed out an absorption band at 420 nm, relating to the surface plasmon resonance of silver nanoparticles. FTIR findings suggested that the diverse functional groups of canthaxanthin bio‐molecules played a significant task in capping the silver nanoparticles. XRD analysis exhibited 40·20 nm for the crystal size of nanoparticles. FESEM and TEM exhibited that the biosynthesized silver nanoparticles were spherical in shape with crystalline nature and the particle size was 40–50 nm. Moreover, the cytotoxicity assessment of the synthesized nanoparticles in HaCaT revealed significant cytotoxicity in the cultured cells with an IC50 value of 43 µg ml−1. Conclusion: Stable silver nanoparticles synthesized using canthaxanthin from D. maris AURCCBT01 were found effective for application in wound healing activity. Significance and Impact of the Study: Biosynthesized silver nanoparticles via canthaxanthin bacterial pigment exhibited their cytotoxicity effect in HaCaT and testified their eventual therapeutic potential in the wound healing activity with no side effects in a cost effective and eco‐friendly process. [ABSTRACT FROM AUTHOR]

Background: Vitiligo is an autoimmune skin condition that affects people globally anywhere, from <0.1% to more than 8% of individuals. The disease destroys skin melanocytes, resulting in a patchy depigmentation of the skin. About 50% of all patients develop the disease before their 20s. Methods: We systematically searched the literature and reviewed the evidence for the use of nutritional supplements and diet in the management of vitiligo. Embase and Medline were searched for diet, herbal, and nutrition-based clinical studies. Additional filters were applied that looked for controlled trial or randomized controlled trial and article or article in press or letter and English and clinical study. We selected clinical studies in humans that showed how diet or natural supplements can improve the symptoms of vitiligo in all of our searches. Results: There were 62 manuscripts that resulted from the PubMed search and 259 from the Embase search. A final of 26 studies were reviewed, and other supplemental case and case-control studies were used to introduce diet components that may influence either exacerbation or amelioration of vitiligo. Possible mechanisms of action are introduced for natural and supplemental interventions. Conclusion: Some of the supplements reviewed include Gingko biloba, oral Polypodium leucotomos, alpha lipoic acid, vitamins B12, D, and E, folic acid, phenylalanine, canthaxanthin, Nigella sativa oil, and other combined herbal bio-actives. Overall, the growing evidence is promising, but more studies are needed in this area to further explore the impact that supplements and diet can have on vitiligo management. The most promising therapies included oral phenylalanine as adjuvant therapy with UVA therapy, oral G. biloba as monotherapy, both of which can be used with other traditional therapies, and oral P. leucotomos with phototherapy or photochemotherapy. [ABSTRACT FROM AUTHOR]

In this study, we studied the levels of both of the main pigments in Salmonidae—astaxanthin (Ax) and canthaxanthin (Cx)—accumulated in the liver, female gonads, and male gonads of rainbow trout (Oncorhynchus mykiss) reared in water containing the fungicide mancozeb (MZ) in concentration levels permitted by European legislation. Experimental fish were divided into three groups: the first was a control group, the second was fed with market feed (containing Ax and Cx), and the third was fed with market feed (containing Ax and Cx) and reared in environmental water containing permissible MZ levels. The diet preparation followed the manufacturer’s recommendations. The accumulated pigment quantities were measured using an HPLC-PDA method after selective extraction: Ax ranged from 2.490 ± 0.247 mg/kg (female gonads, second group) to 0.176 ± 0.007 mg/kg (liver, control group), and Cx—from 2.406 ± 0.166 mg/kg (female gonads, second group) to 0.103 ± 0.010 mg/kg (liver, control group). The pattern of the accumulation of both pigments in the three organs in the specimens of the three groups was sustainable: the amount of Ax was always greater than that of Cx, and the correlation between their concentrations was very high. The pigments were accumulated most intensively in the female gonads, followed by the male gonads and the liver. This trend was confirmed for all three experimental groups. However, the differences in the last third group were very small, and the levels of the xanthophylls accumulated were the lowest. A particular cause of the latter findings was the ongoing detoxification reactions and the disposal of MZ, in which Ax and Cx were involved as antioxidants.