Intraperitoneal and dietary administration of astaxanthin in rainbow trout (Oncorhynchus mykiss)--plasma uptake and tissue distribution of geometrical E/Z isomers.

Astaxanthin enters circulation in salmonid fishes upon intraperitoneal injection (IP) of small doses. Blood uptake and tissue distribution of geometrical E/Z astaxanthin isomers were determined in tissues and plasma of duplicated groups of rainbow trout (Oncorhynchus mykiss, initial weight 550 g) some of which were administered high doses of astaxanthin by IP in a trial lasting for 8 weeks. Doses of 10 (IP10), 50 (IP50) or 100 mg (IP100) astaxanthin (Lucantin Pink, BASF, Germany), respectively, dispersed in phosphate buffered saline were tested in comparison with diets containing 10 (Control) or 60 (Fed 60) mg astaxanthin kg(-1). Astaxanthin concentrations in all examined tissues and plasma were significantly higher in IP50 and IP100 than in controls and Fed 60 (p<0.05). In IP50, 11 mg astaxanthin kg(-1) muscle was detected after 4 weeks, compared to 4 mg kg(-1) in rainbow trout fed 60 mg kg(-1). Concentrations up to 80 and 100 mg astaxanthin kg(-1) were detected in liver and kidney after IP, respectively, whereas fish only fed astaxanthin contained about 2 mg astaxanthin kg(-1). No increase in muscle astaxanthin concentration was found between 4 and 8 weeks in fish given IP, and the muscle astaxanthin concentration in IP50 and IP100 were similar. Muscle concentration and injected dose were curvilinearly correlated and the proportion of ingested dose retained by the muscle was negatively correlated with the amount of injected astaxanthin. Plasma and muscle concentrations of astaxanthin were highly correlated (p<0.0001). Astaxanthin Z-isomers accumulated selectively in the various tissues after IP, whereas all-E-astaxanthin was preferably absorbed into plasma when administered via the diet. There was a selective uptake of all-E-astaxanthin in the muscle of all fish. Mortality was not affected by treatment, but a dose-dependent reduction in SGR was evident after IP. In conclusion, a more rapid and higher uptake of astaxanthin in plasma, muscle, kidney and liver of rainbow trout takes place after IP compared to when astaxanthin is fed via the diet.

Linked models to assess the impacts of climate change on nitrogen in a Norwegian river basin and FJORD system.

Dynamically downscaled data from two Atmosphere-Ocean General Circulation Models (AOGCMs), ECHAM4 from the Max-Planck Institute (MPI), Germany and HadAm3H from the Hadley Centre (HAD), UK, driven with two scenarios of greenhouse gas emissions (IS92a and A2, respectively) were used to make climate change projections. These projections were then used to drive four effect models linked to assess the effects on hydrology, and nitrogen (N) concentrations and fluxes, in the Bjerkreim river basin (685-km(2)) and its coastal fjord, southwestern Norway. The four effect models were the hydrological model HBV, the water quality models MAGIC, INCA-N and the NIVA FJORD model. The downscaled climate scenarios project a general temperature increase in the study region of approximately 1 degrees C by 2030-2049 (MPI IS92a) and approximately 3 degrees C by 2071-2100 (HAD A2). Both scenarios imply increased winter precipitation, whereas the projections of summer and autumn precipitation are quite different, with the MPI scenario projecting a slight increase and the HAD scenario a significant decrease. As a response to increased winter temperature, the HBV model simulates a dramatic reduction of snow accumulation in the upper parts of the catchment, which in turn lead to higher runoff during winter and lower runoff during snowmelt in the spring. With the HAD scenario, runoff in summer and early autumn is substantially reduced as a result of reduced precipitation, increased temperatures and thereby increased evapotranspiration. The water quality models, MAGIC and INCA-N project no major changes in nitrate (NO(3)(-)) concentrations and fluxes within the MPI scenario, but a significant increase in concentrations and a 40-50% increase in fluxes in the HAD scenario. As a consequence, the acidification of the river could increase, thus offsetting ongoing recovery from acidification due to reductions in acid deposition. Additionally, the increased N loading may stimulate growth of N-limited benthic algae and macrophytes along the river channels and lead to undesirable eutrophication effects in the estuarine area. Simulations made by the FJORD model and the HAD scenario indicate that primary production in the estuary might increase up to 15-20%, based on the climate-induced changes in river flow and nitrate concentrations alone.

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 degrees C) on apparent digestibility coefficients (ADC), blood uptake of individual astaxanthin E/Z isomers and metabolism of astaxanthin (3,3'-dihydroxy-beta,beta-carotene-4,4'-dione) were determined in Atlantic salmon. Accumulation of idoxanthin (3,4,3'-trihydroxy-beta,beta-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 degrees C and fed to satiation. Another treatment kept at 12 degrees C was pair-fed with fish fed to satiation at 8 degrees 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 Y(2)O(3) 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 degrees C had approximately 10% higher ADC than fish kept at 8 degrees 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.

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.

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.

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 and its metabolites idoxanthin and crustaxanthin in flesh, skin, and gonads of sexually immature and maturing Arctic charr (Salvelinus alpinus (L.)).

Carotenoid compositions of the flesh, skin, and ovaries were determined in sexually maturing and immature Arctic charr (Salvelinus alpinus) fed diets supplemented with astaxanthin (optical isomer ratio (3S,3'S):(3R,3'S; meso):(3R,3'R); 1:2:1). Astaxanthin comprised 64-79% of the flesh carotenoids, and the 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin, present in a 1:1 ratio, represented 20-35%. The flesh of the sexually maturing charr contained relatively more idoxanthin than that of sexually immature fish (20 vs 35% of total carotenoids), possibly being indicative of a higher metabolic turnover of astaxanthin in the latter. The relative proportions of flesh carotenoids were unaffected by sex. The relative carotenoid composition of ovaries was similar in sexually maturing and immature females. The 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin (ratio 0.7:1) were the major carotenoids (56% of total), followed by crustaxanthin (20%), and astaxanthin comprised less than 5% of ovarian carotenoids. Three glycolic isomers of crustaxanthin were detected (3,4,3',4'-di-cis-:3,4-cis-3',4'-trans-:3,4,3',4'-di-trans-glycolic isomer ratio 2.6:3.1:1) in the ovaries. Sex and maturity status had no apparent effect on the relative composition of skin carotenoids. The skin carotenoids consisted mainly of diesters (82-87% of total carotenoids) and monoesters (7-13% of total carotenoids). Saponification revealed that astaxanthin comprised 85% and idoxanthin 10% of total carotenoids, and minor amounts of tunaxanthin-, lutein-, and zeaxanthin-like metabolites were also present. Maturity status seems to be more important than sex in determining the relative carotenoid composition of the tissues of Arctic charr, with astaxanthin and its metabolites being selectively accumulated in different tissues.

Accumulation of astaxanthin all-E, 9Z and 13Z geometrical isomers and 3 and 3' RS optical isomers in rainbow trout (Oncorhynchus mykiss) is selective.

Concentrations of all-E-, 9Z- and 13Z- geometrical and (3R,3'R), (3R, 3'S) and (3S,3'S) optical isomers of astaxanthin were determined in rainbow trout liver, gut tissues, kidney, skin and blood plasma to evaluate their body distribution. Two cold-pelleted diets containing predominantly all-E-astaxanthin (36.9 mg/kg astaxanthin, 97% all-E-, 0.4% 9Z-, 1.5% 13Z-astaxanthin, and 1.1% other isomers, respectively) or a mixture of all-E- and Z-astaxanthins (35.4 mg/kg astaxanthin, 64% all-E-, 18.7% 9Z-, 12.3% 13Z-astaxanthin, and 2.0% other isomers, respectively), were fed to duplicate groups of trout for 69 d. Individual E/Z isomers were identified by VIS- and 1H-NMR-spectrometry, and quantified by high-performance liquid chromatography. Significantly higher total carotenoid concentration was observed in plasma of trout fed diets with all-E-astaxanthin (P < 0.05). The relative E/Z-isomer concentrations of plasma, skin and kidney were not significantly different among groups, whereas all-E-astaxanthin was higher in intestinal tissues and 13Z-astaxanthin was lower in liver of trout fed all-E-astaxanthin (P < 0.05). The relative amount of hepatic 13Z-astaxanthin (39-49% of total astaxanthin) was higher than in all other samples (P < 0.05). Synthetic, optically inactive astaxanthin was used in all experiments, and the determined dietary ratio between the 3R,3'R:3R, 3'S (meso):3S,3'S optical isomers was 25.3:49.6:25.1. The distribution of R/S-astaxanthin isomers in feces, blood, liver and fillet was similar to that in the diets. The ratio between (3S,3'S)- and (3R,3'R)-astaxanthin in the skin and posterior kidney was ca. 2:1 and 3:1, respectively, regardless of dietary E/Z-astaxanthin composition. The results show that geometrical and optical isomers of astaxanthin are distributed selectively in different tissues of rainbow trout.