Apparent digestibility coefficients and accumulation of astaxanthin E/Z isomers in Atlantic salmon (Salmo salar L.) and Atlantic halibut (Hippoglossus hippoglossus L.)

Apparent astaxanthin (3,3'-dihydroxy-beta,beta-carotene-4,4'-dione) digestibility coefficients (ADC) and carotenoid compositions of the muscle, liver, whole kidney and plasma were compared in Atlantic salmon (Salmo salar) and Atlantic halibut (Hippoglossus hippoglossus) fed a diet supplemented with 66 mg astaxanthin kg(-1) dry matter for 112 days. The astaxanthin source consisted of 75% all-E-, 3% 9Z- and 22% 13Z-astaxanthin, of (3R,3'R)-, (3R,3'S; meso)-, and (3S,3'S)-astaxanthin in a 1:2:1 ratio. The ADC of astaxanthin was significantly higher in Atlantic halibut than in Atlantic salmon after 56 and 112 days of feeding (P < 0.05). The ADC of all-E-astaxanthin was significantly higher than ADC of 9Z-astaxanthin (P < 0.05). Considerably more carotenoids were present in all plasma and tissue samples of salmon than in halibut. Retention of astaxanthin in salmon muscle was 3.9% in salmon and 0 in halibut. All-E-astaxanthin accumulated selectively in the muscle of salmon, and in plasma of salmon and halibut compared with diet. 13Z-astaxanthin accumulated selectively in liver and whole kidney of salmon and halibut, when compared with plasma. A reductive pathway for astaxanthin metabolism in halibut similar to that of salmon was shown by the presence of 3',4'-cis and trans glycolic isomers of idoxanthin (3,3',4'-trihydroxy-beta,beta-carotene-4'-one) in plasma, liver and whole kidney. In conclusion, the higher ADC of astaxanthin in halibut than Atlantic salmon may be explained by lower feed intake in halibut, and the lower retention of astaxanthin by a higher capacity to transform astaxanthin metabolically.     

Astaxanthin from the red crab langostilla (Pleuroncodes planipes): optical R/S isomers and fatty acid moieties of astaxanthin esters

The composition of the fatty acids of astaxanthin esters and the distribution of astaxanthin optical RS isomers in the esterified and unesterified astaxanthin fractions extracted from the meal of the pelagic red crab langostilla (Pleuroncodes planipes; Decapoda, Anomura) were determined. Astaxanthin diesters comprised approximately 70%, monoesterified astaxanthin approximately 12%, and unesterified astaxanthin approximately 10% of total carotenoids, respectively. Unidentified carotenes and minor yellow xanthophylls represented approximately 8% of the total carotenoids. Three astaxanthin diester fractions (ratio 5:4:1) and one monoester fraction were clearly distinguished by thin-layer chromatography, and fatty acid moieties were determined in all of them. Saturated fatty acids accumulated in astaxanthin diesters, but were reduced in the monoester fraction when compared to langostilla crude oil extract (CE). Astaxanthin diesters, but not monoesters were enriched in C16:0 and C18:1n-9, when compared to the CE. Astaxanthin monoesters were rich in polyunsaturated fatty acids (approximately 70% of total fatty acids), in particular C20:5n-3 and C22:6n-3. Acylation of astaxanthin in langostilla seems to be selective rather than specific. The three diesterified astaxanthin fractions of langostilla had a ratio of approximately 3:1:3 between the (3R,3'R)-, (3R,3'S)-, and (3S,3'S)-astaxanthin isomers, whereas in the monoesterified and unesterified fractions the ratio was approximately 4:1:4. The astaxanthin optical RS isomer composition indicates that langostilla is unable to racemize astaxanthin.     

Characteristics of carotenoid features in muscle and ovary from anadromous and river resident types of Alaskan dolly varden charr (Salvelinus malma malma)

• 1.1. The carotenoids in the muscles and eggs from two types of natural Alaskan dolly varden charr, anadromous and river resident types, were examined.
• 2.2. In the muscle from the anadromous charr, astaxanthin was the major component comprising more than 70% of the total, followed by idoxanthin and 4-keto-zeaxanthin.
• 3.3. The egg carotenoid features in the river resident charr were more complicated compared with those in the anadromous fish. A considerable proportion of unidentified carotenoids was found in the eggs from the river resident charr.
• 4.4. Idoxanthin was the main component along with considerable propotions of β-carotene tetrol and astaxanthin in the eggs from the anadromous charr, whereas zeaxanthin and lutein were detected besides idoxanthin and β-carotene tetrol in the eggs from the river resident fish.
• 5.5. The prey was considered to be responsible for the difference in the carotenoid features of the eggs from the anadromous and river resident charr.

     

Plasma appearance of unesterified astaxanthin geometrical E/Z and optical R/S isomers in men given single doses of a mixture of optical 3 and 3'R/S isomers of astaxanthin fatty acyl diesters

Appearance, pharmacokinetics and distribution of astaxanthin all-E-, 9Z- and 13Z-geometrical and (3R,3'R)-, (3R,3'S)- and (3S,3'S)-optical isomers in plasma fractions were studied in three middle-aged male volunteers (41-50 years) after ingestion of a single meal containing first a 10-mg dose equivalent of astaxanthin from astaxanthin diesters, followed by a dose of 100 mg astaxanthin equivalents after 4 weeks. Direct resolution of geometrical isomers and optical isomers of astaxanthin dicamphanates by HPLC after saponification showed that the astaxanthin consisted of 95.2% all-E-, 1.2% 9Z- and 3.6% 13Z-astaxanthin, of (3R,3'R)-, (3R,3'S; meso)- and (3S,3'S)-astaxanthin in a 31:49:20 ratio. The plasma astaxanthin concentration-time curves were measured during 76 h. Astaxanthin esters were not detected in plasma. Maximum levels of astaxanthin (C(max)=0.28+/-0.1 mg/l) were reached 11.5 h after administration and the plasma astaxanthin elimination half-life was 52+/-40 h. The C(max) at the low dose was 0.08 mg/l and showed that, the dose response was non-linear. The (3R,3'R)-astaxanthin optical isomer accumulated selectively in plasma compared to the (3R,3'S)- and (3S,3'S)-isomers, and comprised 54% of total astaxanthin in the blood and only 31% of total astaxanthin in the administered dose. The astaxanthin Z-isomers were absorbed selectively into plasma and comprised approximately 32% of total astaxanthin 6-7.5 h postprandially. The proportion of all-E-astaxanthin was significantly higher in the very low density lipoproteins and chylomicrons (VLDL/CM) plasma lipoprotein fraction than in the high density lipoproteins (HDL) and low denisty lipoproteins (LDL) fractions (P<0.05). The results indicate that a selective process increase the relative proportion of astaxanthin Z-isomers compared to the all-E-astaxanthin before uptake in blood and that the astaxanthin esters are hydrolyzed selectively during absorption.     

Effects of temperature and feed intake on astaxanthin digestibility and metabolism in Atlantic salmon, Salmo salar

The effects of feed intake, growth rate and temperature (8 and 12 °C) on apparent digestibility coefficients (ADC), blood uptake of individual astaxanthin E/Z isomers and metabolism of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) were determined in Atlantic salmon. Accumulation of idoxanthin (3,4,3′-trihydroxy-β,β-carotene-4-one) in plasma was used to indicate metabolic transformation of astaxanthin. Quadruplicate groups of fish were subjected to three different treatments; one treatment was kept at 12 °C and fed to satiation. Another treatment kept at 12 °C was pair-fed with fish fed to satiation at 8 °C, resulting in a restricted feeding regime for the former treatment. After 2 months of feeding, the fish were fed a single meal containing ballotini glass beads to determine individual feed intake and Y₂O₃ as an inert marker to determine ADCs. The faeces samples were pooled into 6 categories according to individual meal size (range 0.2–1.5% of body weight) and the ADCs for different meal sizes were determined. ADCs of astaxanthin ranged from 20% to 60% but were not significantly correlated with meal size. However, fish kept at 12 °C had approximately 10% higher ADC than fish kept at 8 °C (p = 0.032). Growth rate and plasma astaxanthin concentration were higher at higher temperature and higher ration. Plasma concentration of idoxanthin was not affected by temperature or by meal size. The incidence of fin erosion and non-feeding individuals was significantly higher among fish fed a restricted ration indicating more aggressive interactions. Fish with visible fin damage had a tendency for having higher idoxanthin content in plasma than fish without noticeable fin damage. It is concluded that temperature but not individual meal size affect ADC of astaxanthin, whereas both influence plasma astaxanthin levels and may therefore affect the efficiency of astaxanthin utilization.     

Use of the benzyl mesylate for the synthesis of tetrahydrofuran lignan: syntheses of 7,8-trans, 7',8'-trans, 7,7'-cis, and 8,8'-cis-virgatusin stereoisomers

The benzyl mesylate was employed to construct the tetrasubstituted tetrahydrofuran lignan with avoiding Friedel-Crafts type of reaction. The optically pure 7,8-trans, 7',8'-trans, 7,7'-cis, and 8,8'-cis-virgatusin stereoisomers were synthesized. The enantiomeric excess was >99%.     

Adaptative role of carotenoids and carotenoproteins in Cyclops kolensis Lilljeborg (Crustacea: Copepoda) specimens to extremely eutrophical conditions

The authors, using column, thin-layer, and ion-exchange chromatography, investigated carotenoid and carotenoprotein complex content in Cyclops kolensis specimens from an extremely eutrophic pond. The following carotenoids were found to be present: beta-carotene, beta-cryptoxanthin, lutein epoxide, crustaxanthin, 4'-hydroxyechinenone, canthaxanthin, and astaxanthin. Carotenoprotein complex containing astaxanthin as the prosthetic group name gamma-crustacyanine was purified from Cyclops kolensis individuals examined. The authors justify the adaptative role of these pigments in Cyclops kolensis specimens in extremely eutrophical conditions.     

Carotenoids with a 5,6-dihydro-5,6-dihydroxy-beta-end group, from yellow sweet potato "Benimasari", Ipomoea batatas Lam

A series of carotenoids with a 5,6-dihydro-5,6-dihydroxy-beta-end group, named ipomoeaxanthins A (1), B (2), C1 (3) and C2 (4) were isolated from the flesh of yellow sweet potato "Benimasari", Ipomoea batatas Lam. Their structures were determined to be (5R,6S,3'R)-5,6-dihydro-beta,beta-carotene-5,6,3'-triol (1), (5R,6S,5'R,6'S)-5,6,5',6'-tetrahydro-beta,beta-carotene-5,6,5'6'-tetrol (2), (5R,6S,5'R,8'R)-5',8'-epoxy-5,6,5',8'-tetrahydro-beta,beta-carotene-5,6-diol (3), and (5R,6S,5'R,8'S)-5',8'-epoxy-5,6,5',8'-tetrahydro-beta,beta-carotene-5,6-diol (4) by UV-Vis, NMR, MS and CD data.     

Plasma appearance and distribution of astaxanthin E/Z and R/S isomers in plasma lipoproteins of men after single dose administration of astaxanthin

Appearance, pharmacokinetics, and distribution of astaxanthin E/Z and R/S isomers in plasma and lipoprotein fractions were studied in 3 middle-aged male volunteers (37-43 years) after ingestion of a single meal containing a 100 mg dose of astaxanthin. The astaxanthin source consisted of 74% all-E-, 9% 9Z-, 17% 13Z-astaxanthin (3R,3'R-, 3R,3'S; meso-, and 3S,3'S-astaxanthin in a 1:2:1 ratio). The plasma astaxanthin concentration--time curves were measured during 72 hr. Maximum levels of astaxanthin (1.3 +/- 0.1 mg/L) were reached 6.7 +/- 1.2 hr after administration, and the plasma astaxanthin elimination half-life was 21 +/- 11 hr. 13Z-Astaxanthin accumulated selectively, whereas the 3 and 3'R/S astaxanthin distribution was similar to that of the experimental meal. Astaxanthin was present mainly in very low-density lipoproteins containing chylomicrons (VLDL/CM; 36-64% of total astaxanthin), whereas low-density lipoprotein (LDL) and high-density lipoprotein (HDL) contained 29% and 24% of total astaxanthin, respectively. The astaxanthin isomer distribution in plasma, VLDL/CM, LDL, and HDL was not affected by time. The results indicate that a selective process increases the relative proportion of astaxanthin Z-isomers compared to the all-E-astaxanthin during blood uptake and that astaxanthin E/Z isomers have similar pharmacokinetics.     

Carotenoid content in Lota lota (L.) individuals in various biological activity periods

The authors investigated the carotenoid content in the particular parts of Lota lota in summer, autumn, and winter, i.e. when burbots exhibit the lowest and highest activity. By means of columnar and thin-layer chromatography, the following carotenoids were found to be present: alpha-carotene, beta-carotene, e-carotene, beta-cryptoxanthin, neothxanthin, lutein, 3'-epilutein, zeaxanthin, tunaxanthin, antheraxanthin, lutein epoxide, echinenone, 3'-hydroxyechinenone, idoxanthin, canthaxanthin, alpha-doradexanthin, beta-doradexanthin, astaxanthin, diatoxanthin, parasiloxanthin, monadoxanthin, 7,8-dihydroparasiloxanthin, mutatoxanthin and rhodoxanthin. In the Lota lota individuals examined, the content of carotenoids was found to differ in winter and summer. The total carotenoid content ranged from 0.067 (gonads of males) of to 6.095 micrograms g-1 wet weight (fins of males from December).     

Engineered maize as a source of astaxanthin: processing and application as fish feed

Astaxanthin from a transgenic maize line was evaluated as feed supplement source conferring effective pigmentation of rainbow trout flesh. An extraction procedure using ethanol together with the addition of vegetal oil was established. This resulted in an oily astaxanthin preparation which was not sufficiently concentrated for direct application to the feed. Therefore, a concentration process involving multiple phase partitioning steps was implemented to remove 90 % of the oil. The resulting astaxanthin raw material contained non-esterified astaxanthin with 12 % 4-keto zeaxanthin and 2 % zeaxanthin as additional carotenoids. Isomeric analysis confirmed the exclusive presence of the 3S, 3′S astaxanthin enantiomer. The geometrical isomers were 89 % all-E, 8 % 13-Z and 3 % 9-Z. The incorporation of the oily astaxanthin preparation into trout feed was performed to deliver 7 mg/kg astaxanthin in the final feed formulation for the first 3.5 weeks and 72 mg/kg for the final 3.5 weeks of the feeding trial. The resulting pigmentation of the trout fillets was determined by hue values with a colour meter and further confirmed by astaxanthin quantification. Pigmentation properties of the maize-produced natural astaxanthin incorporated to 3.5 µg/g dw in the trout fillet resembles that of chemically synthesized astaxanthin. By comparing the relative carotenoid compositions in feed, flesh and feces, a preferential uptake of zeaxanthin and 4-keto zeaxanthin over astaxanthin was observed.     

The carotenoids of eggs of wild and farmed cod (Gadus morhua)

• 1.1. Eggs of wild cod, and of farmed cod fed (a) a diet supplemented with astaxanthin and (b) a diet supplemented with both astaxanthin and canthaxanthin, were analysed with respect to carotenoids.
• 2.2. The total carotenoid contents in eggs were 0.7 ppm for wild cod and 0.5 ppm for farmed cod.
• 3.3. Cod, having white flesh, deposit ketocarotenoids in the eggs, preferably astaxanthin.
• 4.4. Canthaxanthin can replace astaxanthin in the eggs, but astaxanthin appears to be deposited preferentially when both carotenoids are present in the diet.
• 5.5. The isomer distribution of (3S, 3′S):(3R, 3′S, meso):(3R, 3′R) astaxanthin in the eggs reflected the isomer composition of the diet.
• 6.6. Echinenone, 4′-hydroxyechinenone, adonixanthin and zeaxanthin encountered in cod eggs may represent reductive metabolites of canthaxanthin and astaxanthin.

     

三疣梭子蟹卵巢发育过程中主要类胡萝卜素组成变化及其与抗氧化性能的关系

实验研究了三疣梭子蟹(Portunus trituberculatus)卵巢发育过程中(Ⅰ—V期)组织色泽、类胡萝卜素组成与含量、抗氧化和非特异性免疫指标的变化规律,进一步探讨了肝胰腺中类胡萝卜素含量变化与抗氧化指标的关系。结果表明:(1)卵巢发育期间,卵巢指数(GSI)显著增加(P<0.05),肝胰腺指数(HSI)整体呈先升后降的趋势;卵巢的红度(a*)值和黄度(b*)值、肝胰腺的亮度(L*)值和b*值均呈显著上升趋势,但卵巢中L*值呈下降趋势。(2)在卵巢发育过程中,卵巢中的总类胡萝卜素、虾青素、叶黄素和β-胡萝卜素含量均为先升后降的趋势,虾青素含量在Ⅳ期最高;肝胰腺中的虾青素含量呈上升趋势,而β-胡萝卜素含量为显著下降趋势;内表皮中的总类胡萝卜素、虾青素、叶黄素、海胆烯酮和β-胡萝卜素含量均呈现下降趋势;就不同组织中类胡萝卜素含量而言,内表皮中虾青素含量最高。卵巢和肝胰腺的L*值与总类胡萝卜素含量呈显著负相关,卵巢的a*值和b*值均与总类胡萝卜素、虾青素、叶黄素、海胆烯酮和β-胡萝卜素含量呈显著正相关。肝胰腺的a*值与各类胡萝卜素含量无显著相关性, b*值仅与虾青素含量呈显...     

Effect of diets enriched in Delta6 desaturated fatty acids (18:3n-6 and 18:4n-3), on growth, fatty acid composition and highly unsaturated fatty acid synthesis in two populations of Arctic charr (Salvelinus alpinus L.)

This study aimed to test the hypothesis that diets containing relatively high amounts of the Delta6 desaturated fatty acids stearidonic acid (STA, 18:4n-3) and gamma-linolenic acid (GLA, 18:3n-6), may be beneficial in salmonid culture. The rationale being that STA and GLA would be better substrates for highly unsaturated fatty acid (HUFA) synthesis as their conversion does not require the activity of the reputed rate-limiting enzyme, fatty acid Delta6 desaturase. Duplicate groups of two Arctic charr (Salvelinus alpinus L.) populations with different feeding habits, that had been reported previously to show differences in HUFA biosynthetic capacity, were fed for 16 weeks on two fish meal based diets containing 47% protein and 21% lipid differing only in the added lipid component, which was either fish oil (FO) or echium oil (EO). Dietary EO had no detrimental effect on growth performance and feed efficiency, mortalities, or liver and flesh lipid contents in either population. The proportions of 18:2n-6, 18:3n-3, 18:3n-6, 18:4n-3, 20:3n-6 and 20:4n-3 in total lipid in both liver and flesh were increased by dietary EO in both populations. However, the percentages of 20:5n-3 and 22:6n-3 were reduced by EO in both liver and flesh in both strains, whereas 20:4n-6 was only significantly reduced in flesh. In fish fed FO, HUFA synthesis from both [1-(14)C]18:3n-3 and [1-(14)C]20:5n-3 was significantly higher in the planktonivorous Coulin charr compared to the demersal, piscivorous Rannoch charr morph. However, HUFA synthesis was increased by EO in Rannoch charr, but not in Coulin charr. In conclusion, dietary EO had differential effects in the two populations of charr, with HUFA synthesis only stimulated by EO in the piscivorous Rannoch morph, which showed lower activities in fish fed FO. However, the hypothesis was not proved as, irrespective of the activity of the HUFA synthesis pathway in either population, feeding EO resulted in decreased tissue levels of n-3HUFA and 20:4n-6. This has been observed previously in salmonids fed vegetable oils, and thus the increased levels of Delta6 desaturated fatty acids in EO did not effectively compensate for the lack of dietary HUFA.     

Carotenoid and lipid content in muscle of Atlantic salmon, Salmo salar, transferred to seawater as 0+ or 1+ smolts

Accumulation of lipids and carotenoids, including 4'-hydroxyechinenone (4'-hydroxy-beta,beta-carotene-4-one), growth and condition factor were investigated in Atlantic salmon (Salmo salar) transferred to seawater as 0+ and 1+ smolts. Salmon were fed a diet with 30 mg/kg astaxanthin (3,3'-dihydroxy-beta,beta-carotene-4,4'-dione) and 30 mg/kg canthaxanthin (beta,beta-carotene-4,4'-dione) for 35 weeks. The 0+ smolt contained more carotenoids than the 1+ smolt when mass differences were corrected for (P<0.0001), a difference also reflected by the tristimulus colour measurements (C1E a*- and b*-values). Astaxanthin and canthaxanthin comprised more than 93% of the total carotenoids, but small differences were observed in carotenoid composition. The condition factor was significantly higher in 0+ than 1+ smolts after correction for mass differences (P<0.01). There was a high correlation between ln-transformed muscle lipid (%) and ln-transformed body mass for 0+(R2=0.94) and 1+smolts (R2=0.97). The canthaxanthin metabolite 4'-hydroxyechinenone was isolated from muscle of Atlantic salmon fed a diet supplemented with canthaxanthin. It was characterised and identified by its absorption maximum (lambda(max)=458 nm in n-hexane), mass spectrometry (M+=566) and co-chromatography with authentic standard obtained by NaBH4-reduction of canthaxanthin on thin-layer chromatography and HPLC. HPLC of the camphanates of 4'-hydroxyechinenone revealed a stereoselective transformation in favour of the (4'S)-isomer, the (4'S) and (4'R)-isomers comprising approximately 81 and 19% of the total 4'-hydroxyechinenone, respectively. The percentage of 4'-hydroxyechineone of total carotenoids ranged from 1.3 to 3.1% and declined with fish size (P<0.001). We conclude that effects of time of seawater transfer of Atlantic salmon smolts have significant effect on carotenoid accumulation and other quality traits. The detailed biochemical and physiological basis for these differences require further elucidation.     

Metabolism of three stereoisomers of astaxanthin in the fish, rainbow trout and tilapia

In rainbow trout (Salmo gairdneri), the dietary astaxanthin diesters were mostly absorbed and accumulated in their integuments keeping their configurations, and partially metabolized to (3R, 3'R)-zeaxanthin (major) and/or (3R, 3'S)-zeaxanthin (medium) and/or (3S,3'S)-zeaxanthin (minor). In tilapia (Tilapia nilotica), the three stereoisomers of astaxanthin diesters were promptly metabolized to only (3S,3'S)-astaxanthin, and subsequently to (3R,3'R)-zeaxanthin and/or (3R,3'S)-zeaxanthin and/or (3S,3'S)-zeaxanthin at an invariable ratio, 4:1:0.3. The above facts indicate that the conversion from 3S- to 3R-configuration was carried out in vivo, and vice versa, and that astaxanthins were reductively metabolized to zeaxanthins in both the fish.     

Carotenoid content in Anguilla anguilla (L.) individuals undertaking spawning migration

The authors investigated the carotenoid content in different parts of Anguilla anguilla (L.) undertaking spawning migration, in spring, summer and autumn. By means of column and thin-layer chromatography, the following carotenoids were found to be present: beta-carotene, epsilon-carotene, beta-cryptoxanthin, neothxanthin, lutein, tunaxanthin, zeaxanthin, lutein epoxide, 3'-hydroxyechincnone, canthaxanthin, idoxanthin, phoenicoxanthin, alpha-doradexanthin, beta-doradexanthin and astaxanthin. In the eel examined individuals a different carotenoid content was found in October. In winter when eels do not feed and therefore do not absorb carotenoids, carotenoid content decreases in the liver, the intestines, and particularly in the muscles. In spring when eels undertake active life carotenoid concentration increases rapidly in these organs within a month. In summer during intensive predation, carotenoid concentration in the muscles reaches a maximum.     

Antioxidant lignans from Larrea tridentata

Three lignans, (7S,8S,7'S,8'S)-3,3',4'-trihydroxy-4-methoxy-7,7'-epoxylignan, meso-(rel 7S,8S,7'R,8'R)-3,4,3',4'-tetrahydroxy-7,7'-epoxylignan, and (E)-4,4'-dihydroxy-7,7'-dioxolign-8(8')-ene, together with 10 known compounds, were isolated from the leaves of Larrea tridentata. The structures of the new compounds were determined primarily from 1D and 2D NMR spectroscopic analysis. Their antioxidant activities against intracellular reactive oxygen species were evaluated in HL-60 cells.     

Heterologous production of two unusual acyclic carotenoids, 1,1'-dihydroxy-3,4-didehydrolycopene and 1-hydroxy-3,4,3',4'-tetradehydrolycopene by combination of the crtC and crtD genes from Rhodobacter and Rubrivivax

Acyclic hydroxy carotenoids were produced from lycopene and 3,4-didehydrolycopene in Escherichia coli by combining different carotenogenic genes including the carotene hydratase gene crtC and the carotene 3,4-desaturase gene crtD. The genes originated either from Rhodobacter species or Rubrivivax gelatinosus. It was shown that the product of crtD from Rubrivivax unlike the one from Rhodobacter is able to convert 1-HO-3,4-didehydrolycopene to 1-HO-3,4,3',4'-tetradehydrolycopene (=3,4,3',4'-tetradehydro-1,2-dihydro-psi,psi-caroten-1-ol). Thus, only when the desaturase from Rubrivivax is expressed can this novel carotenoid be obtained. In the presence of crtC from Rubrivivax, another carotenoid 1,1'-(HO)(2)-3,4-didehydrolycopene (=3,4-didehydrolycopene-1,2,1',2'-tetrahydro-psi,psi-caroten-1,1'-diol) not found in a non-transgenic organism before is formed in E. coli. Its accumulation under these conditions and its absence when crtC from Rubrivivax is replaced by the corresponding gene from Rhodobacter is discussed. The function of the different crtC and crtD genes in the pathway leading to the individual carotenoids is outlined. Since 1,1'-(HO)(2)-3,4-didehydrolycopene could not be produced in substantial amounts and 1-HO-3,4,3',4'-tetradehydrolycopene has not been described before, their structural characteristics were determined for the definite assignment of their identity. This included spectral properties, determination of relative molecular mass as well as the number of hydroxy groups by mass spectroscopy and NMR spectroscopy for 1,1'-(HO)(2)-3,4-didehydrolycopene.     

The carotenoids of wild and blue disease affected farmed tiger shrimp (Penaeus monodon, Fabricus)

1. The main carotenoids in wild Penaeus monodon exoskeleton were astaxanthin di- and mono-esters, astaxanthin, and beta-carotene. 2. Wild P. monodon exoskeleton contained on average 26.3 ppm total carotenoid; normally pigmented farmed shrimp had a similar concentration (25.3 ppm). 3. Exoskeletons of farmed "blue" P. monodon (i.e. blue-coloured, as opposed to the normally red-blue/black banded shrimp) contained significantly less total carotenoid (4.3-7 ppm). The only major carotenoid being astaxanthin. 4. Commercially available diets contained only trace quantities of canthaxanthin. 5. Nutritional deficiency with respect to carotenoids is suggested as the cause of blue disease in farmed P. monodon.