Canthaxanthin Concentration Research Articles

Effect of microencapsulated canthaxanthin and apo-ester on egg yolk color and antioxidant capacity in laying hens

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.

Effects of different concentrations of canthaxanthin microencapsulated with gelatin or lignosulfonate on laying performance, yolk color of hens

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 < .05), and the LMC group showed better colouring than the GMC group at the same CX concentration (p < .05). Meanwhile, with the increasing of CX concentration, the yolk colour increased by linear and quadratic (p < .001). CX-treatment improved serum total superoxide dismutase (T-SOD) level (p < .05). In conclusion, LMC was superior to GMC in improving egg yolk colour, and antioxidant function, and there was no adverse impact on productive performance, and 8 mg/kg was the optimal dosage of LMC. Therefore, LS could be used as a potential substitute for GL in the CX microencapsulation industry of laying hens.

Extraction, characterization and the antioxidant activity of carotenoid pigment canthaxanthin from an aero-terrestrial and filamentous green microalga Trentepohlia sp.

Trentepohlia sp. (TP1) was collected from tree barks at Kodaikanal, Tamil Nadu, India. The largest amount of carotenoid pigment (5.72 %) was achieved using a 7:3 ratio of methanol to chloroform. For coconut oil, the Rf value of carotenoid pigment was 0.67 and for solvents, it was 0.95. In column chromatography, elution 2 yielded 64.096 ± 0.17 mg/mL of carotenoid using petroleum ether and acetone (9:1) as the mobile phase. Approximately 90 % of canthaxanthin was derived from purified carotenoid pigment, according to GC–MS and FT-IR analyses. The concentration of canthaxanthin was inversely proportional to free radicals generated in the DPPH free radical scavenging assay. The IC50 values of canthaxanthin from Trentepohlia sp. (TP1) was 23.37 ± 1.52 μg/mL, which was close to the positive control Ascorbic acid (22.49 ± 0.43 μg/mL). Therefore, this study reveals the prospective approach to the extraction of canthaxanthin from Trentepohlia sp. for various biotechnological applications.

Can Canthaxanthin Intensify The Color of the Blood Swordtail Xiphophorus helleri?

The coloring has a great influence on the commercialization of ornamental fish. The aim of this study was to evaluate different concentrations of canthaxanthin in the diet of the blood swordtail Xiphophorus helleri, to obtain a more intense red color. Six concentrations of canthaxanthin (0, 50, 100, 250, 400 and 600 mg kg-1 diet) were used. The experiment lasted 60 days. Fish were evaluated for increased red pigmentation through the use of photographs (performed by smartphone) and imaging applications considering the Hunter method and the CMYK and productive performance. No significant differences were observed for productive performance. The use of photographs by means of a smartphone and the use of imaging applications proved to be adequate to assess differences in color in the species. Swordtail red pigmentation did not show significant increase regardless of canthaxanthin dosages. Varieties of ornamental fish bred for red coloration may have limits for increased color due to the storage capacity of carotenoids by chromatophores.

Long-Term Supplementation of Canthaxanthin Does Not Inhibit Gastric Epithelial Cell Proliferation in Helicobacter mustelae-Infected Ferrets

The effect of canthaxanthin (CX), a non-provitamin A carotenoid, on gastric epithelial proliferation was studied in ferrets colonized with Helicobacter mustelae, which causes a chronic gastritis and an increased gastric epithelial cell proliferation. Seven spayed female ferrets were dosed by gavage with CX beadlets (50 mg/kg body wt, 5 d/wk) over 2 y, whereas seven control animals were given placebo beadlets. At the end of the 2-y-period, ferrets were killed, and gastric tissues were obtained from the antrum and body regions. A cell-proliferating biomarker, proliferating cell nuclear antigen (PCNA), was assayed by immunohistochemistry. The PCNA positivity was measured by a computer-based image analysis system. Serum concentrations of carotenoids, retinoids and tocopherols were analyzed by HPLC. Serum antioxidant status was measured by the oxygen radical absorbance capacity (ORAC) assay. The PCNA positivity in both antrum and body regions was not significantly different between CX-fed ferrets and controls. Serum CX concentrations were significantly higher in CX-fed ferrets vs. controls (P<0.001), whereas levels of other carotenoids, retinoids and tocopherols were not significantly different. The ORAC values were not significantly different between groups. This study does not suggest inhibitory effects of CX on gastric epithelial cell proliferation in H. mustelae infected ferrets.

The effects of canthaxanthin microencapsulation on yolk color and canthaxanthin deposition in egg yolk of laying hens

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.

Effects of Dietary Inclusion of Canthaxanthin- and α-Tocopherol-Loaded Liposomes on Growth and Muscle Pigmentation of Rainbow Trout (Oncorhynchus mykiss)

Dietary inclusion of canthaxanthin, a common carotenoid pigment, has been long practiced in aquaculture to give the favorable flesh color in farmed salmonids. However, carotenoids are associated with limited solubility and poor physicochemical stability, and their dose in fish feed is widely regulated. In this study, we included canthaxanthin- and α-tocopherol-loaded liposomes into fish diets and evaluated the effects of supplemented fish feed on fish growth, color, nutrition, and canthaxanthin deposition in fillets of cultured rainbow trout (Oncorhynchus mykiss). The liposomes were fabricated using lecithin as phospholipids with the initial concentrations (IC = mcanthaxanthin/mlipids, % wt/wt) of canthaxanthin at 0.1%, 0.5%, and 1.0%. Particle size characterization showed that liposome mean sizes were 109.70 ± 6.36, 105.10 ± 8.41, and 109.20 ± 5.66 nm (mean ± SD; n = 3), respectively, corresponding with liposomes synthesized at canthaxanthin IC = 0.1%, IC = 0.5%, and IC = 1%. The polydispersity index (PDI) of all samples remained lower than 0.2. There were no significant differences in the mean size and PDI between blank lecithin liposome and canthaxanthin- and α-tocopherol-loaded liposomes. The encapsulation efficiency of canthaxanthin- and α-tocopherol-loaded liposomes decreased when increasing the concentration of canthaxanthin in lecithin liposomes, with EE% values of IC = 0.1%, IC = 0.5%, and IC = 1% being 85.3 ± 2.1, 72.9 ± 1.8, and 55.3 ± 2.6, respectively. For fish growth, at the end of the experiment, final weight was significantly higher in fish fed with diet supplemented with 1 g/kg canthaxanthin- and α-tocopherol-loaded liposomes (IC = 0.5%) in comparison to other experimental control groups. The difference in color of the salmon muscle was most apparent after two months of feeding. However, after three months, there was no noticeable change in the color score of the fish muscle, indicating saturation of color of the fish muscle. The above results suggest the potential of canthaxanthin- and a-tocopherol-loaded liposomes as the red pigment in fish aquaculture.

Nitrogen Deficiency-Dependent Abiotic Stress Enhances Carotenoid Production in Indigenous Green Microalga Scenedesmus rubescens KNUA042, for Use as a Potential Resource of High Value Products

The microalgal strain Scenedesmus rubescens KNUA042 was identified in freshwater in Korea and characterized by evaluating its stress responses in an effort to increase lipid and carotenoid production. Under a two-stage cultivation process, the algal strain that generally exhibits optimal growth at a nitrate (source of nitrogen) concentration of 0.25 g L−1 was challenged to different exogenous stimuli—salinity (S), light intensity (L), combined L and S (LS), and nitrogen deficiency (C)—for 14 days. Lipid production and carotenoid concentration increased in a time-dependent manner under these physicochemical conditions during the culture periods. Lipid accumulation was confirmed by thin layer chromatography, BODIPY staining, and fatty acid composition analysis, which showed no differences in the algal cells tested under all four (C, S, L, and LS) conditions. The quality of biodiesel produced from the biomass of the algal cells met the American Society for Testing and Materials and the European standards. Total carotenoid content was increased in the LS-treated algal cells (6.94 mg L−1) compared with that in the C-, S-, and L-treated algal cells 1.75, 4.15, and 1.32 mg L−1, respectively). Accordingly, the concentration of canthaxanthin and astaxanthin was also maximized in the LS-treated algal cells at 1.73 and 1.11 mg g−1, respectively, whereas lutein showed no differences in the cells analyzed. Conversely, chlorophyll a level was similar among the C-, S-, and LS-treated algal cells, except for the L-treated algal cells. Thus, our results suggested that S. rubescens KNUA042 was capable of producing carotenoid molecules, which led to the maximum values of canthaxanthin and astaxanthin concentrations when exposed to the combined LS condition compared with that observed when exposed to the salinity condition alone. This indicates that the algal strain could be used for the production of high-value products as well as biofuel. Furthermore, this article provides the first evidence of carotenoid production in S. rubescens KNUA042.

Synthesis, Regulation and Degradation of Carotenoids Under Low Level UV-B Radiation in the Filamentous Cyanobacterium Chlorogloeopsis fritschii PCC 6912.

Carotenoids in cyanobacteria play an important role in protecting against and in repairing damage against low level UV-B radiation. Here we use transcriptomics and metabolomic HPLC pigment analysis to compare carotenoid pathway regulation in the filamentous cyanobacterium Chlorogloeopsis fritschii PCC 6912 exposed to white light and to white light supplemented with low level UV-B. Under UV-B changes in carotenoid transcription regulation were found associated with carotenogenesis (carotenoid synthesis), photoprotection and carotenoid cleavage. Transcriptional regulation was reflected in corresponding pigment signatures. All carotenogenesis pathway genes from geranylgeranyl-diphosphate to lycopene were upregulated. There were significant increases in expression of gene homologs (crtW, crtR, cruF, and cruG) associated with routes to ketolation to produce significant increases in echinenone and canthaxanthin concentrations. There were gene homologs for four β-carotene-ketolases (crtO and crtW) present but only one crtW was upregulated. Putative genes encoding enzymes (CruF, CrtR, and CruG) for the conversion of γ-carotene to myxol 2′-methylpentoside were upregulated. The hydroxylation pathway to nostaxanthin via zeaxanthin and caloxanthin (gene homologs for CrtR and CrtG) were not upregulated, reflected in the unchanged corresponding pigment concentrations in zeaxanthin, caloxanthin and nostaxanthin, Transcripts for the non-photochemical quenching related Orange-Carotenoid-Protein (OCP) and associated Fluoresence-Recovery-Protein (FRP) associated with photoprotection were upregulated, and one carotenoid binding Helical-Carotenoid-Protein (HCP) gene homolog was downregulated. Multiple copies of genes encoding putative apocarotenoid related carotenoid oxygenases responsible for carotenoid cleavage were identified, including an upregulated apo-β-carotenal-oxygenase gene homologous to a retinal producing enzyme. Our study provides holistic insight into the photoregulatory processes that modulate the synthesis, photoprotection and cleavage of carotenoids in cyanobacterial cells exposed to low level UV-B. This is important to understanding how regulation of metabolism responds to a changing environment and how metabolism can be modulated for biotechnological purposes.

Microencapsulation of microbial canthaxanthin with alginate and high methoxyl pectin and evaluation the release properties in neutral and acidic condition

Canthaxanthin (CX) is an orange-red keto-carotenoid with high antioxidant activity. This functional pigment is sensitive to oxygen, light, pH and heat. In this study, CX was produced by the Dietzia natronolimnaea HS-1 and was encapsulated in Alginate (Alg) and Alg-high methoxyl pectin (HMP) through O/W/O multiple emulsion/external gelation method to developed resistant microparticles among acidic and neutral pHs. Results showed that initial CX concentration had a significant influence on total CX (TCX), surface CX (SCX), microencapsulation efficiency (EE) and particles size. The highest EE% for Alg (60.21 ± 0.18) and Alg-HMP (70.60 ± 0.68) were obtained with CX initial concentration of 11 and 18 μg/mg, respectively. Alg microparticles showed smaller size compare to Alg-HMP microcapsules. Presence of CX in microparticles and good antioxidant activity was confirmed by FT-IR spectroscopy and DPPH assay, respectively. CX in vitro release was 66% and 49% in acidic condition and 76% and 50% in neutral condition for Alg and Alg-HMP, respectively. Thus, Alg-HMP-CX18 microparticles were selected to be used in both neutral and acidic foods such as milk and fermented milks products as an antioxidant and a colorant agent.

Pigment composition, glutathione and tocopherols in green algal and cyanobacterial lichens and their response to different light treatments

This study investigated photosynthetic pigments chlorophyll a and b, carotenoids (including xanthophyll cycle pigments) and antioxidants glutathione and tocopherols contents in chloro- (Lobaria pulmonaria, Lasallia pustulata) and cyanolichens (Lobaria scrobiculata, Peltigera canina) from different habitats and of different geographical origin. Lichen thalli were treated with various levels of irradiance (from 100 to 1500 mmol m-2 s-1) for various time periods (from 20 min. to 5 h). The extent of increase of zeaxanthin content after different light treatments differed among chlorolichens, clearly distinguishing the species from light and shade habitats. Irrespective of light treatment, β-carotene content was always higher in cyanobacterial species than in green algal species. Highest canthaxanthin concentration, as well as β-carotene concentration, was found in L. scrobiculata from shade habitat. The content of total glutathione was the same in the same species from different collection sites. On the contrary, contents of a-tocopherol differed in the same species from different collection sites.

Astaxanthin and Canthaxanthin (Xanthophyll) as Supplements in Rainbow Trout Diet: In Vivo Assessment of Residual Levels and Contributions to Human Health

Many studies have demonstrated that xanthophylls, such as astaxanthin, have beneficial effects in human health, and their use in food supplements is thus encouraged. Moreover, such nutrients are frequently used in aquaculture to meet consumer demand for salmonoid flesh pigmentation. In this study different xanthophyll administration protocols were tested to verify pigmentation properties and safety of such mixtures of additives in trout diet. Residues of xanthophylls in muscle samples were determined by HPLC-MS/MS, reaching levels of 3.70 ± 0.04 mg/kg (astaxanthin) and 1.21 ± 0.06 mg/kg (canthaxanthin) during a 56 day administration period. On the basis of the average fish consumption in the human diet, the highest astaxanthin and canthaxanthin concentrations detected in trout fillets could result in weekly intakes of 1.63 and 0.53 mg, respectively, in humans; these values are not sufficient to achieve the positive effects described by many authors, but their residues could still represent an important source of carotenoids, alternative to the use of synthetic dietary supplements.

Tolerance of poultry against an overdose of canthaxanthin as measured by performance, different blood variables and post-mortem evaluation

Canthaxanthin (CXN) is a red pigment, which is broadly used in broiler chickens for skin pigmentation, in laying hens for the coloration of egg yolks and in poultry breeders for improving the antioxidant status of eggs. In order to investigate the safety of this feed additive under conditions of an accidental oversupply, studies in all target poultry categories were performed, comparing a non-supplemented control to treatments with the respective recommended dietary supplementation of CXN and a ten times overdose of the recommended CXN level. Performance, mortality and a number of hematological and blood biochemical variables as well as post-mortem evaluations were taken as parameters to assess the effects of CXN overdosing. In broilers performance was not influenced by treatment with CXN at 25 or 250mg/kg feed. The hematological traits of the CXN groups were either not different from the control or remained within the normal physiological range. Concentration of CXN in blood plasma increased (P<0.001) in a proportional manner to the CXN supplementation in the feed. Some blood chemistry variables responded to the CXN treatments, but remained close to normal values. No mortality occurred in the overdose treatment and neither regular health examination nor post-mortem evaluation revealed any detrimental effects of CXN on broiler health. Laying performance of hens was not influenced by CXN supplementation with 8 or 80mg/kg feed. The CXN content in eggs responded linearly to supplementation (P<0.001). None of the measured blood variables were affected by treatment. The dissection of experimental birds showed indications of friable livers in the CXN supplemented hens, but no other effects on gross-morphology were observed. In breeders body weight and productive performance were not different among treatments. Egg weight with 6mg CXN/kg feed was higher (P=0.045) than in the control group. The CXN content in eggs increased proportionally to CXN supplementation (P<0.001). No differences in fertility were observed among the treatments, but hatchability of fertile eggs was depressed by overdosing CXN (P<0.001). Certain hematology and blood chemistry traits differed between the treatments, but the values remained within the normal range. The final post-mortem examination did not reveal any health problems in these breeders, which were related to the dietary treatments or attributable to the high CXN contents. In summary CXN at dietary supplementation doses of up to ten times the recommended levels is safe for broilers, laying hens and poultry breeders.

The antioxidant properties of canthaxanthin and its potential effects in the poultry eggs and on embryonic development of the chick. Part 2.

Among more than 750 known carotenoids, canthaxanthin (CX) has a special place as a carotenoid with proven antioxidant and other biologically-relevant functions. A great body of evidence indicates that CX possesses high antioxidant activity that was shown in various in vitro model systems as well as in animal experiments in vivo. Antioxidant defences of chicken eggs are based mainly on vitamin E and carotenoids and their concentrations in the egg yolk is dependent on their dietary provision. CX is well absorbed from the feed and effectively transferred to the egg yolk and further to the developing embryo. Increased CX concentration in embryonic tissues is associated with increased resistance to oxidative stress. Since oxidative stress is an important element of increased embryonic mortality during the last week of incubation it is highly likely that dietary CX could support chicken viability after hatch. In well designed experiments, it was proven that CX dietary supplementation of the breeder's diet significantly increased anti-oxidative status in the egg yolk and newly hatched chicks and as a result hatching rate of chicken eggs was significantly increased. Taken together, the aforementioned results clearly indicate that CX provides a great deal of benefits for chicken eggs, embryos and chickens during early postnatal development.

Relationships between dietary carotenoids, body tissue carotenoids, parasite burden, and health state in wild mallard ( Anas platyrhynchos) ducklings

While rodents and other mammals have traditionally served as models for studying carotenoid physiology, many wild animals from a variety of other taxa utilize carotenoids for self-maintenance and reproduction and accumulate far greater concentrations than those found in mammals. Though we have basic understandings of the control and value of carotenoids in some wild animal systems, many gaps remain. For example, parasites and pathogens impose severe survival constraints on free-ranging organisms, but little is known of how carotenoids work in concert with the immune system to combat natural infectious challenges. Furthermore, due to the high mortality rate from which many young animals suffer, health and carotenoid status during the early stages of development may be critical to survival. The relative importance of dietary versus physiological mechanisms for carotenoid uptake has also been understudied in the wild. To begin to shed light on these issues, we studied relationships between dietary and tissue carotenoids, hematological immune parameters, and endoparasitism of wild mallard ( Anas platyrhynchos) ducklings at a variety of ages. Lutein, zeaxanthin, β-cryptoxanthin, β-carotene, and canthaxanthin were the most common carotenoids in liver, plasma, and gut contents. We found that, early in development (when food intake is limited), carotenoids were comparatively concentrated in internal tissue (e.g., liver), presumably a carry-over from maternal contributions in yolk, but as ducklings approached independence (and increasingly fed on their own) concentrations were greatest in gut contents. Canthaxanthin concentrations were lower in the plasma and liver of older individuals compared to younger ducklings, even though gut canthaxanthin concentration did not change with age. Additionally, β-carotene was nearly absent from circulation, despite moderate levels within the gut, suggesting a high rate of conversion to retinol. Using principal components analysis, we revealed a correlation between an increased ability to assimilate dietary carotenoids and lower levels of chronic stress (as assessed by lower heterophil-to-lymphocyte ratios) and a correlation between a reduced carotenoid status and increased investment in the immune system (as assessed by higher total leukocyte count). We also found that individuals without parasites had an overall reduced carotenoid status. Thus, we demonstrate age-specific differences in carotenoid allocation in growing animals from a precocial bird species and provide correlational evidence that parasitism and health in wild animals are related to carotenoid status and assimilation ability.

Optimization of canthaxanthin production by Dietzia natronolimnaea HS-1 from cheese whey using statistical experimental methods

Sequential methodology combining a screening test by fractional factorial design and an optimization test by central composite design was applied to enhance canthaxanthin production by Dietzia natronolimnaea HS-1 from cheese whey in shake flask cultures. Six variables (pH, luminous intensity, inoculum percent and concentrations of whey lactose, yeast extract and KH 2PO 4) were studied with the screening test. The results revealed that three factors of pH, concentrations of whey lactose and yeast extract had greater influence on the canthaxanthin production ( P < 0.01). The central composite design was then used to determine the maximum canthaxanthin concentration. The optimum conditions for the highest canthaxanthin production (2871 ± 76 μg/l) were pH 7.66, whey lactose concentration 55.54 g/l and yeast extract concentration 7.36 g/l.

Optimization of Canthaxanthin Production by Dietzia natronolimnaea HS-1 Using Response Surface Methodology

Sequential methodology combining a screening stage by fractional factorial design and an optimization stage by central composite design was applied to enhance canthaxanthin production of Dietzia natronolimnaea HS-1 in shake flask cultures. Five variables (pH, luminous intensity, inoculum percent, concentration of glucose and concentration of NaCl) were studied with the first design and the results revealed that three factors (pH, concentration of glucose and concentration of NaCl) had greater influence on the canthaxanthin production (p<0.01). A central composite design was then used in the second step to determine the maximum canthaxanthin concentration. The optimum condition for the highest canthaxanthin production (5.32 mg L(-1)) was a pH of 7.53, glucose concentration of 25.90 g L(-1) and NaCI concentration of 3.42 g L(-1).

Thermotropic phase behaviour of lipid bilayers containing carotenoid pigment canthaxanthin: a differential scanning calorimetry study

In this study we address the problem of the effect of canthaxanthin on the thermotropic properties of lipid membranes formed with lipids which differ in the thickness of their hydrophobic core, size of polar heads or presence of the ester carbonyl group. For all the lipids a decrease in main transition enthalpy has been observed, indicating that canthaxanthin alters the membrane properties in its gel phase. The strongest influence of canthaxanthin on main phase transition and pretransition has been observed for the lipid having the thinnest hydrophobic region. Component analysis indicates a distinct cooperativity change, which most probably colligates with the formation of new thermotropic phases. The effect of canthaxanthin has been almost negligible in the case of phosphatidylethanolamines. The absence of the ester carbonyl group results in different thermotropic behavior, especially for low canthaxanthin concentrations. The effect of canthaxanthin is explained in terms of its organization within the membrane.

Effect of canthaxanthin content of the maternal diet on the antioxidant system of the developing chick

1. Effects of canthaxanthin supplementation of the maternal diet on the antioxidant system of the developing chick were investigated. 2. Three hundred and twenty female broiler breeder birds were housed in one of 4 controlled environment rooms with 3 replicates for all treatments, with the exception of the control treatment of which there were 4 replicates. All birds received one of 5 diets: control low xanthophyll diet, or the same diet supplemented with 3, 6, 12 or 24 mg/kg canthaxanthin in the form of Carophyll® Red. At 30 weeks of age 60 eggs from each of the 5 groups were incubated. At d 16 of the embryo development, at d 1 and d 7 posthatch tissue samples were collected and analysed by HPLC-based methods. 3. Canthaxanthin accumulation in the egg yolk was proportional to dietary content. Furthermore, at 12 to 24 mg/kg canthaxanthin was associated with an increase in γ-tocopherol concentration in the egg yolk. Canthaxanthin was transferred from the egg yolk to the developing embryo and, as a result, its concentration in the liver of the embryo at 16 and in 1-d-old chicks was increased. Even at d 7 posthatch canthaxanthin concentration in the chicken liver was elevated. 4. Canthaxanthin supplementation of the maternal diet at 12 mg/kg was associated with an increased α-tocopherol concentration in the liver of 1-d-old chicks and resulted in decreased tissue susceptibility to lipid peroxidation. 5. Canthaxanthin supplementation at 6 to 24 mg/kg was also associated with a delay in α-tocopherol depletion from the liver for 7-d posthatch. As a result of the increased canthaxanthin and vitamin E concentrations in the liver of 7-d-old chicks, tissue susceptibility to lipid peroxidation decreased. 6. The results support an idea that dietary carotenoids can modulate antioxidant systems of the developing chicken.

Chlorophyll fluorescence characteristics of the cyanobacterial lichen Peltigera rufescens under field conditions: II. Diel and annual distribution of metabolic activity and possible mechanisms to avoid photoinhibition

Photosystem II fluorescence of the terrestrial cyanobacterial lichen Peltigera rufescens , together with microclimate parameters, was recorded continuously over a complete year at two quasi-natural growing sites in a xerotherrnic steppe formation in the Botanical Garden Würzburg. From the fluorescence data, metabolically active phases of the poikilohydrous lichen could easily be distinguished from desiccation or frost-induced inactivity. According to the fluorescence signal patterns, the daily time courses of lichen performance could be grouped in four response types: (1) metabolically active (i.e., measurable quantum yield) throughout the day due to favourable hydration; (2) lichen active at dawn due to nightly rain or dew condensation with subsequent drying; (3) activation during the daylight hours through rain or thawing; (4) no photosystem II activity recognisable all day. The seasonal distribution of these types is analysed. Overall, the lichen remained inactivated for 46.5% of the total year, it was photosynthetically active in the light for 25.6% and hydrated during the nights for 27.9% of the time. Earlier laboratory experiments had shown that dry thalli of P. rufescens were not affected by high light, but, in the hydrated state, became drastically photoinhibited when suddenly exposed to high light stress. However, no, or only minor, photoinhibition was recognisable during the field measurements. We calculated light receipt by the lichen in nature under both dry and hydrated conditions. For the longest periods of light stress, the lichen was well protected through desiccation. Nevertheless, substantial periods of time occurred when the hydrated thalli were exposed to high light and some form of photoprotection must have taken place. There was a clear correlation between light receipt and thallus content of certain carotenoids (especially the ratio between concentrations of canthaxanthin and β-carotene) and the hypothesis is supported that canthaxanthin formation is involved in photoprotection. Experiments under controlled conditions with P. rufescens revealed a complex relationship between gross photosynthetic CO 2 uptake and relative electron transport as obtained from fluorescence measurements. In particular, quantum yield overestimated CO 2 assimilation when high light occurred in combination with CO 2 diffusion being inhibited by suprasaturation of the thallus with water. Thus, we could not use the fluorescence data to predict carbon gain of the lichen under field conditions, and possible reasons are discussed.