Dietary Astaxanthin Levels Research Articles

Effects of dietary astaxanthin on growth performance, immunity, and tissue composition in largemouth bass, Micropterus salmoides

This study examined the effects of feeding largemouth bass (Micropterus salmoides) with diets containing different doses of astaxanthin (0, 50, 100, 150, and 200 mg/kg) for 8 weeks. The results showed that the values of weight gain significantly increased from 620.32 ± 50.38% to 826.14 ± 33.49% as dietary astaxanthin levels increased from 0 mg/kg to 100 mg/kg. When the astaxanthin level exceeded 150mg/kg, the weight gain rate showed a downward trend, but there was no significant difference among of the 100, 150 and 200 mg/kg groups. The feed conversion ratio (FCR) and protein efficiency ratio (PER) were also improved by adding astaxanthin to diets (P < 0.05). Meanwhile, adding astaxanthin to the feed increased the length and thickness of intestinal villus and muscle layer thickness (P < 0.05). The astaxanthin supplementation increased the expression of the NF-E2-related factor (Nrf2) gene and reduced malondialdehyde (MDA) content and the expression of apoptosis genes Caspase-9 and Caspase-3 (P < 0.05), indicating that it has a good antioxidant ability. Furthermore, adding astaxanthin increased the content of non-specific immune markers and decreased the expression levels of the inflammatory factors interleukin-15 (IL-15) and tumor necrosis factor-α (TNF-α). Moreover, fish fed diets with astaxanthin exhibited lower blood cortisol levels (P < 0.05). The proportions of C20:4n6 (ARA) and C20:5n3 (EPA) in the liver decreased with increasing dietary astaxanthin levels. Based on WGR and SGR values, the optimal addition level of astaxanthin in largemouth bass feed is 134.8 mg/kg ~ 135.75 mg/kg. In summary, the appropriate dietary astaxanthin enhanced the antioxidant capacity and immune response of largemouth bass and had a positive effect on its intestinal health.

Dietary Astaxanthin Can Promote the Growth and Motivate Lipid Metabolism by Improving Antioxidant Properties for Swimming Crab, Portunus trituberculatus.

This study aimed to assess the influence of varying dietary levels of astaxanthin (AST) on the growth, antioxidant capacity and lipid metabolism of juvenile swimming crabs. Six diets were formulated to contain different AST levels, and the analyzed concentration of AST in experimental diets were 0, 24.2, 45.8, 72.4, 94.2 and 195.0 mg kg-1, respectively. Juvenile swimming crabs (initial weight 8.20 ± 0.01 g) were fed these experimental diets for 56 days. The findings indicated that the color of the live crab shells and the cooked crab shells gradually became red with the increase of dietary AST levels. Dietary 24.2 mg kg-1 astaxanthin significantly improved the growth performance of swimming crab. the lowest activities of glutathione (GSH), total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and peroxidase (POD) were found in crabs fed without AST supplementation diet. Crabs fed diet without AST supplementation showed lower lipid content and the activity of fatty acid synthetase (FAS) in hepatopancreas than those fed diets with AST supplementation, however, lipid content in muscle and the activity of carnitine palmitoyl transferase (CPT) in hepatopancreas were not significantly affected by dietary AST levels. And it can be found in oil red O staining that dietary 24.2 and 45.8 mg kg-1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas. Crabs fed diet with 195.0 mg kg-1 AST exhibited lower expression of ampk, foxo, pi3k, akt and nadph in hepatopancreas than those fed the other diets, however, the expression of genes related to antioxidant such as cMn-sod, gsh-px, cat, trx and gst in hepatopancreas significantly down-regulated with the increase of dietary AST levels. In conclusion, dietary 24.2 and 45.8 mg kg-1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas and im-proved the antioxidant and immune capacity of hemolymph.

Effects of Synthetic Astaxanthin on the Growth Performance, Pigmentation, Antioxidant Capacity, and Immune Response in Black Tiger Prawn (Penaeus monodon).

Synthetic astaxanthin is an effective nutritional strategy for improving shrimp body color and promoting growth. However, the optimal amount of astaxanthin in feed also varies with the synthetic technology and purity. In the present study, five diets containing different doses of synthetic astaxanthin (0% (CON), 0.02% (AX0.02), 0.04% (AX0.04), 0.08% (AX0.08), and 0.16% (AX0.16)) were administered to Penaeus monodon (initial body weight: 0.3 ± 0.03 g) for 8 weeks. With an increase in astaxanthin content in feed, weight gain and specific growth rate increased initially and subsequently decreased, with the highest value appearing at AX0.08. Dietary astaxanthin supplementation obviously improved the carapace and muscle color by enhancing astaxanthin pigmentation. Meanwhile, the fatty acid profile was altered by dietary astaxanthin, as evidenced by a decline in palmitic acid proportion, along with an increase in n-3 polyunsaturated fatty acids (n-3 PUFA) contents in muscle. In addition, dietary astaxanthin supplementation regulated prawn's antioxidant capacity. In the hemolymph, the activities of glutamic pyruvic transaminase (GPT) showed a significantly decrease trend with linear effect. The activities of glutamic oxaloacetic transaminase (GOT) and the contents of malondialdehyde (MDA) were first downregulated and then upregulated with significantly quadratic pattern. In the hepatopancreas, the activities of superoxide dismutase (SOD) and the contents of MDA were significantly downregulated with the increase of dietary astaxanthin levels. Reduced glutathione (GSH) contents and catalase (CAT) activities were also significantly decreased in group AX0.08. Correspondingly, astaxanthin decreased GSH and MDA contents under transportation stress. Moreover, the mRNA expression of immune genes (traf6, relish, and myd88) were inhibited by dietary astaxanthin supplementation. Based on the results of polynomial contrasts analysis and Duncan's test, dietary synthetic astaxanthin is a suitable feed additive to improve the growth, body color, antioxidant capacity, and nonspecific immunity of P. monodon. According to the second-order polynomial regression analysis based on the weight gain, the optimal supplementation level of dietary astaxanthin was 90 mg kg-1 in P. monodon.

Effects of long-term Haematococcus pluvialis astaxanthin feeding on the growth, coloration, and antioxidant capacity of commercial-sized Oncorhynchus mykiss

Haematococcus pluvialis is an important source of natural astaxanthin, which plays a key role in the regulation of color, antioxidant capacity, and immunity in aquatic animals. However, it is unclear that the effects of long-term H. pluvialis astaxanthin feeding on the growth performance, coloration, and antioxidant capacity of commercial-sized rainbow trout Oncorhynchus mykiss. The commercial feed of O. mykiss was used as the basic feed, and 15, 30 mg/kg H. pluvialis astaxanthin were added to prepare isonitrogenous and isolipidic experimental diets, defined as HPA0, HPA15, and HPA30, respectively. Juvenile O. mykiss with an initial weight of 0.60 kg were fed with three experimental diets for 4 months, which was conducted to investigate the effects of long-term H. pluvialis astaxanthin feeding on the growth performance, coloration, antioxidant capacity, and biochemical composition. The results showed that the weight gain rate and specific growth rate of the HPA30 from 0 to 4 months were significantly higher than those of the other two diet groups. In the 4th month, the viscerosomatic index of O. mykiss significantly increased with increasing dietary astaxanthin levels. The redness (a*), DSM SalmoFan™ scores, and astaxanthin content of fillets significantly increased with increasing dietary astaxanthin levels during the whole feeding trial. The activities of total antioxidant capacity and glutathione peroxidase in the serum and liver, and serum immunoglobulin (IgM) content significantly increased with increasing dietary astaxanthin levels, while the levels of total antioxidant capacity, and malondialdehyde in the serum and liver showed a decreasing trend. The contents of total lipids in the fillet of O. mykiss increased significantly with increasing dietary astaxanthin levels, while the percentages of total saturated fatty acid (∑SFA), C18:3n3, and n-3/n-6 PUFA ratio showed a decreasing trend; the percentages of C18:2n6 and total n-6 polyunsaturated fatty acids (∑n-6PUFA) in the HPA15 and HPA30 were significantly higher than those of the HPA0. In conclusion, four months of feeding with 30 mg/kg H. pluvialis astaxanthin diet could improve the growth performance, fillet coloration, antioxidant capacity, and fillet total lipids content of commercial-sized O. mykiss.

Suitable natural astaxanthin supplementation with Haematococcus pluvialis improves the physiological function and stress response to air exposure of juvenile red swamp crayfish (Procambarus clarkii)

High mortality during transportation has restricted industrial development of red swamp crayfish (Procambarus clarkii), especially juveniles, in China. Supplementation with Haematococcus pluvialis has been proved to promote crustacean survival and growth. Therefore, this study investigated the effects of dietary natural astaxanthin derived from H. pluvialis on the growth performance, pigmentation, digestion, antioxidant capacity, immunity, and response to air exposure stress of juvenile red swamp crayfish. Five isonitrogenous and isolipidic diets were formulated containing a graded H. pluvialis powder inclusion (0, 0.15, 0.30, 0.45 and 0.60%) level. The results indicated that dietary astaxanthin significantly improved the survival rate and weight gain rate of juvenile crayfish (P < 0.05). As dietary astaxanthin levels increased, a* values in the carapace, muscle, and ovaries improved and the carotenoid content significantly increased (P < 0.05). Lipase (LPS), and cellulase (CL) activities in the hepatopancreas and intestines, and α-amylase, and pepsin (PEP) activities in the hepatopancreas, significantly increased and then decreased with increasing dietary astaxanthin levels (P < 0.05). Dietary astaxanthin significantly decreased the malondialdehyde (MDA) content in the hemolymph (P < 0.05). Total superoxide dismutase (T-SOD), total antioxidant capacity and acid phosphatase (ACP) activities in the hepatopancreas and hemolymph, as well as alkaline phosphatase in the hepatopancreas, followed a similar pattern as the digestive enzymes (P < 0.05). Furthermore, dietary astaxanthin significantly improved succinate dehydrogenase (SDH) activity in the hepatopancreas and muscle after a 24-h air exposure stress test, while decreasing the MDA and lactic acid content (LD) in muscle (P < 0.05). Based on the quadratic regression analysis of LPS, PEP, CL, T-SOD, ACP and SDH in hepatopancreas, and MDA and LD in muscle, the optimal dietary natural astaxanthin content for juvenile red swamp crayfish ranges from 63.55 to 84.40 mg kg−1.

Dietary supplementation of astaxanthin increased growth, colouration, the capacity of hypoxia and ammonia tolerance of Pacific white shrimp (Litopenaeus vannamei)

Astaxanthin (AX) is a naturally occurring carotenoid often used as a dietary supplement in the Pacific white shrimp (Litopenaeus vannamei) culture industry. This study evaluated the effects of chemically synthesized astaxanthin on growth performance, survival, stress resistance, immune responses, and pigmentation of the Pacific white shrimp fed diets supplemented with five dietary levels of AX containing 0, 20, 40, 80, and 160 mg kg−1. The feeding trial was conducted for 8 weeks. The results showed the individuals fed diets supplemented with AX exhibited better growth performance, whose final body weight (FBW), body weight gain (BWG), specific growth ratio (SGR), and Myostatin (MSTN) showed a dose-dependent increase in Astaxanthin levels. Following acute hypoxia and ammonia stress test, the survival rate (SR) of shrimp fed with 40, 80 and 160 mg kg−1 diets were higher than that of the control group. AX diet groups improved their capacity of antioxidant defense to prevent oxidative damage, including increasing the activities of acid phosphatase (ACP), total antioxidant capacity (T-AOC), and decreasing the activities of superoxide dismutase (SOD) and catalase (CAT), the content of malondialdehyde (MDA) compared to the control group. In addition, the gene expression of various antioxidant enzymes in the hepatopancreas of shrimp was significantly upregulated higher such as manganese superoxide dismutase (MnSOD) and glutathione S-transferase (GST). High expression of hypoxia-inducible factor-1α (HIF-1α) and glutamate dehydrogenase (GDH-β), glutamine synthetase (GS) in 80 and 160 mg kg−1 group indicated their effect on glycolysis possibly, which is vital on energy production required. Quadratic regression analysis indicated that the optimal levels for growth and pigmentation were 126.94 mg kg−1 and 138.96 mg kg−1 diet, respectively. In conclusion, Astaxanthin can enhance growth performance, alleviate oxidative and ammonia stress, improving the immunity of Pacific white shrimp.

Dual-Function Analysis of Astaxanthin on Golden Pompano (Trachinotus ovatus) and Its Role in the Regulation of Gastrointestinal Immunity and Retinal Mitochondrial Dysfunction Under Hypoxia Conditions.

The present study investigated the potential mechanisms of astaxanthin in the regulation of gastrointestinal immunity and retinal mitochondrial function of golden pompano (Trachinotus ovatus). Triplicate groups of juvenile T. ovatus (mean initial weight: 6.03 ± 0.01 g) were fed one of six diets (D1, D2, D3, D4, D5, and D6) for 8 weeks, with each diet containing various concentrations of astaxanthin (0, 0.0005, 0.001, 0.005, 0.01, or 0.1%, respectively). Growth performance of fish fed the D2–D5 diets was higher than that of fish fed the D1 diet; however, growth performance and survival of fish deteriorated sharply in fish fed the D6 diet. Gut villus in fish fed the D2–D5 diets were significantly longer and wider than that of fish fed the D6 diet. Feeding with D2–D5 diets led to increased abundance of Bacillus, Pseudomonas, Oceanobacillus, Lactococcus, Halomonas, Lactobacillus, and Psychrobacter while abundance of Vibrio and Bacterium decreased. Additionally, feeding with the D6 diet resulted in a sharp decline in Pseudomonas and Lactobacillus abundance and a sharp increase in Vibrio abundance. A low dissolved oxygen environment (DO, 1.08 mg/L) was conducted for 10 h after the rearing trial. No fish mortality was observed for any of the diet treatments. Lysozyme (LZY) activity in fish fed the D6 diet decreased sharply and was significantly lower than that in other groups. ROS production also decreased sharply in fish fed the D6 diet. Moreover, the conjunctiva and sclera in the fish fed the D6 diet were indistinguishable. Suitable dietary astaxanthin supplementation levels (0.005–0.1%) exerting a neuroprotective effect from low dissolved oxygen environments is due to up-regulated expression of anti-apoptotic factors, such as phosphorylated Bcl-2-associated death promoter (pBAD), phosphorylated glycogen synthase kinase-3β (pGSK-3β), Bcl-2 extra large (Bcl-xL), and down-regulated expression of Bcl-2-associated X protein (Bax) pro-apoptotic factor in retinas. Furthermore, suitable dietary astaxanthin levels (0.0005–0.01%) suppressed up-regulation of critical mitochondrial components, such as peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), mitochondrial transcription factor A (TFAM), and mitochondrial DNA (mtDNA), while excessive astaxanthin supplementation produces the opposite effect. In brief, high-dose astaxanthin arouses and aggravates low dissolved oxygen-induced inflammation, oxidative stress, intestinal disorder, retinal apoptosis, and retinal mitochondrial dysfunction in T. ovatus. Second-degree polynomial regression of WG indicated that the optimum dietary astaxanthin for juvenile T. ovatus is 0.049%.

Effects of supplementing natural astaxanthin from Haematococcus pluvialis to laying hens on egg quality during storage at 4°C and 25°C

The objective of this study was to evaluate the effects of different levels of dietary natural astaxanthin (ASTA) (from the microalga Haematococcus pluvialis) and storage at 4°C and 25°C on the quality of eggs from laying hens. Nongda No. 3 laying hens (n = 450) were randomly allocated to 1 of 5 dietary treatments. Each treatment had 6 replicates of 15 hens each. All birds were assigned to a corn–soybean meal–based diet containing 0, 20, 40, 80, or 160 mg/kg natural ASTA for 4 wk. A total of 540 eggs were collected at the end of the 4-week feeding trial. Sixty fresh eggs were collected and measured for egg quality within 24 h after collection. The other 480 eggs were used in a factorial arrangement with 5 dietary ASTA levels, 4 storage times, and 2 storage temperatures. During the 8-week storage period at 4°C and 25°C, egg quality measurements were performed every 2 wk on 12 eggs per treatment. No significant effects (P > 0.05) on yolk index, yolk pH, Haugh units, weight loss, or eggshell strength were observed with increasing concentrations of dietary ASTA. Yolk color darkened linearly with increasing dose of ASTA (P < 0.05). During storage of eggs, yolk index and Haugh units decreased significantly (P < 0.05), whereas yolk pH and weight loss increased (P < 0.05). An interaction was observed between dietary ASTA level and storage time on yolk index, yolk color, and Haugh units (P < 0.05). These results demonstrated that dietary ASTA from H. pluvialis delayed the decrease in yolk index and yolk color during storage at 4°C and 25°C. Therefore, we speculate that there may be a combined effect of dietary ASTA level and storage time on egg internal quality; this information may provide additional options by which to extend the storage time of eggs.

Red coloration varies with dietary carotenoid access and nutritional condition in kittiwakes.

Carotenoid-based ornaments are common signaling features in animals. Although the mechanisms that link color-based signals to individual condition is key to understanding the evolution and function of these ornaments, they are most often poorly known. Several hypotheses have been posited. They include: (i) the role of foraging abilities on carotenoid acquisition and thereby carotenoid-based ornaments, and (ii) the role of internal processes linked to individual quality on the allocation and conversion of carotenoids in integuments. Here, we tested the influence of dietary carotenoid access versus internal process on gape coloration in black-legged kittiwakes (Rissa tridactyla). This seabird displays a vibrant red gape, whose coloration varies with individual quality in males and is due to the deposition of red ketocarotenoids, such as astaxanthin. We decreased hydroxycarotenoid and ketocarotenoid levels in plasma, but increased efficiency in internal processes linked to nutritional condition, by supplementing breeding males with capelin, a natural energy-rich fish prey. We found that, despite having lower carotenoid levels in plasma, supplemented birds developed redder coloration than control birds, but only in the year when dietary levels of astaxanthin in the natural diet were low. In contrast, in the astaxanthin-rich year, supplemented males had a less-red gape than unsupplemented birds. These results suggest that inter-individual differences in internal processes may be sufficient to maintain the honesty of gape coloration under conditions of low dietary astaxanthin levels. Nonetheless, when inter-individual variations in dietary astaxanthin levels are elevated (such as in the crustacean-rich year), carotenoid access seems a more limiting factor to the expression of gape coloration than internal processes. Therefore, our study revealed a complex mechanism of gape color production in kittiwakes, and suggests that the main factor maintaining the condition dependency of this ornaments may vary with environmental conditions and diet composition.

Effects of Dietary Astaxanthin on Growth Performance, Hepatic Antioxidative Activity, hsp70, and HIF-1α Gene Expression of Juvenile Golden Pompano (Trachinotus ovatus)

The present study was conducted to investigate the effects of different astaxanthin (AST) levels on growth performance, hepatic antioxidative activity, heat shock protein 70 (hsp70), and hypoxia-inducible factor-1 alpha (HIF-1α) gene expression of juvenile golden pompano. Fish (mean initial body weight 5.8±0.05g) were fed six isonitrogenous and isoenergetic diets (AST-0, AST-0.005, AST-0.01, AST-0.05, AST-0.1, AST-0.2) containing various supplemented levels of astaxanthin (0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, respectively) in triplicate for 8 weeks. Growth performance (final body weight, FBW; weight gain, WG), and survival of fish fed diets containing astaxanthin above 0.01% were significantly higher (P&lt;0.05) than of fish fed AST-0 and AST-0.005 diets; feed conversion ratio (FCR) showed the opposite trend (P&lt;0.05). Fish fed 0.01% astaxanthin diet showed the highest value of survival. Hepatic antioxidant status (total antioxidant status, TAS; superoxide dismutase, SOD; carbonyl protein content) of shrimp improved significantly when dietary astaxanthin was over 0.01%. Relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA increased with increased dietary astaxanthin levels. The relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA of shrimp fed diets containing astaxanthin above 0.01% were obviously higher than those of shrimp fed AST-0 and AST-0.005 diets. Linear regression analysis on WG and HIF-1a mRNA indicated that the optimum dietary AST levels for optimal growth and immunity of juvenile pompano were 0.011% and 0.013%, respectively.

Effects of Dietary Astaxanthin on Growth Performance, Hepatic Antioxidative Activity, hsp70, and HIF-1α Gene Expression of Juvenile Golden Pompano (Trachinotus ovatus)

The present study was conducted to investigate the effects of different astaxanthin (AST) levels on growth performance, hepatic antioxidative activity, heat shock protein 70 (hsp70), and hypoxia-inducible factor-1 alpha (HIF-1α) gene expression of juvenile golden pompano. Fish (mean initial body weight 5.8±0.05g) were fed six isonitrogenous and isoenergetic diets (AST-0, AST-0.005, AST-0.01, AST-0.05, AST-0.1, AST-0.2) containing various supplemented levels of astaxanthin (0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, respectively) in triplicate for 8 weeks. Growth performance (final body weight, FBW; weight gain, WG), and survival of fish fed diets containing astaxanthin above 0.01% were significantly higher (P&lt;0.05) than of fish fed AST-0 and AST-0.005 diets; feed conversion ratio (FCR) showed the opposite trend (P&lt;0.05). Fish fed 0.01% astaxanthin diet showed the highest value of survival. Hepatic antioxidant status (total antioxidant status, TAS; superoxide dismutase, SOD; carbonyl protein content) of shrimp improved significantly when dietary astaxanthin was over 0.01%. Relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA increased with increased dietary astaxanthin levels. The relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA of shrimp fed diets containing astaxanthin above 0.01% were obviously higher than those of shrimp fed AST-0 and AST-0.005 diets. Linear regression analysis on WG and HIF-1a mRNA indicated that the optimum dietary AST levels for optimal growth and immunity of juvenile pompano were 0.011% and 0.013%, respectively.

Effects of Dietary Inclusion of Astaxanthin on Growth, Muscle Pigmentation and Antioxidant Capacity of Juvenile Rainbow Trout (Oncorhynchus mykiss).

This study was designed to investigate the effects of dietary astaxanthin levels on growth performance, feed utilization, muscle pigmentation, and antioxidant capacity in juvenile rainbow trout. Four experimental diets were formulated to contain 0, 50, 75, and 100 mg/kg astaxanthin (designed as AX0, AX50, AX75, and AX100). Each diet was fed to triplicate groups of fish (18.5 g/fish) for 10 weeks. Growth performance and muscle composition of fish were not affected by dietary astaxanthin levels. Total carotenoid concentration in the muscle of fish fed the AX50 diet was higher than that of fish fed the AX0 diet, but no significant differences were observed between these fish and those fed the AX75 and AX100 diets. Muscle astaxanthin content increased with increased astaxanthin in the diet. Deposition of astaxanthin in the flesh resulted in a decrease in lightness and an increase in redness and yellowness. The fillets from trout fed the AX75 diet had significantly lower lightness than trout fed the AX50 and AX100 diets. Fish fed the AX50 and AX75 diets showed significantly lower catalase activity than those fed the control diet. Total antioxidant status increased significantly in all astaxanthin supplemented groups when compared to the control group. Superoxide dismutase activity was significantly decreased in fish fed the AX50 diet compared to fish fed the AX0 diet. These findings suggest that while fillet pigmentation increased with increasing dietary astaxanthin concentration, indices of fish antioxidant capacity may not be affected in a dose dependent manner.

Maternal Intake of Astaxanthin Improved Hatchability of Fertilized Eggs Stored at High Temperature

This work aimed at examining the interactive effect of maternal intake of astaxanthin (AX) and storage conditions (temperature and period) on the hatchability of fertilized eggs. Single comb White Leghorn laying hens were allocated to 4 groups with cocks. Experimental diets with 4 levels of AX were prepared by supplementing AX to a basal diet. AX levels were 0, 5, 10 and 20ppm. Eggs from each treatment group were stored for 0, 4, 7, 14 and 21 days at either 10 or 21°C of storage temperature with 70% of relative humidity. The number of hatched chicks was counted and un-hatched eggs were used to check the age of embryo death. When fertilized eggs were stored at 10°C, the hatchability was kept at high level regardless of storage period. At 10°C of storage temperature, maternal intake of AX had no effect on the hatchability of fertilized eggs. On the other hand, the hatchability of eggs stored at 21°C was significantly lower than that at 10°C, and lowered hatchability was restored by maternal intake of AX. Elevated levels of dietary AX from 5 to 20ppm gradually restrained the decrease in hatchability at 21°C. On the mortality of embryos from 0 to 7 days of incubation, the interaction between dietary AX levels and storage temperature was significant. However, after 7 days of incubation, there was no significant interaction between dietary AX levels and storage temperature, and the effect of AX was not significant. These results suggest that the lowered hatchability of eggs stored at high temperature was restored by maternal feeding of dietary AX, and the beneficial effect of AX may be effective at early stage of embryo development.

Effects of Dietary Supplementation of Astaxanthin on Production Performance, Egg Quality in Layers and Meat Quality in Finishing Pigs

Two experiments were conducted separately to study the effect of astaxanthin on production performance and egg quality in laying hens and meat quality in finishing pigs. In Experiment 1, four hundred Brown Hy-Line layers, 26 weeks of age, were randomly divided into five treatments according to a single factorial arrangement. Each treatment had four replicates comprising 20 birds each. The dietary treatments were: 0, 0.7, 0.9, 1.1 and 1.3 ppm of astaxanthin fed for 14 days. Then all the birds were fed an astaxanthin-free diet (0 ppm astaxanthin) for an additional 7 days. The results showed that dietary astaxanthin had no significant effect on layer production performance. There was no significant effect (p>0.05) on egg weight, yolk height and Haugh unit (HU) with increasing dietary astaxanthin level and increased storage time. Yolk color was linearly increased (p), BW, were randomly divided into three treatments according to a single factorial arrangement. Each treatment had three replicates comprising 4 pigs each. The dietary treatments were: 0, 1.5 and 3.0 ppm of astaxanthin fed for 14 days. The results showed that dietary astaxanthin had no significant effects on production performance. There was a linear effect (p0.05) on the TBARS value, drip loss, meat color, marbling and , , values. Cholesterol concentration in meat was not affected by dietary addition of astaxanthin. It could be concluded that astaxanthin supplementation was beneficial to improve egg yolk color; egg quality during storage and it also could improve the meat quality of finishing pigs.

Astaxanthin deposition in fillets of Atlantic salmon Salmo salar L. fed two dietary levels of astaxanthin in combination with three levels of α-tocopheryl acetate

The influence of alpha-tocopheryl acetate (alpha-TOAc) on plasma concentration and fillet deposition of dietary astaxanthin was investigated in Atlantic salmon Salmo salar L. The diets were added 30 or 50 mg kg(-1) astaxanthin, and 200, 400 or 800 mg kg(-1) alpha-TOAc at each astaxanthin level. Improved flesh deposition of astaxanthin by 8-14% was achieved for fish fed diets with 30 and 50 mg kg(-1) astaxanthin, respectively, by the dietary addition of 800 compared with 200 mg kg(-1) alpha-TOAc. These results were supported by CIE[1976]L*a*b* tristimulus redness measurements (a* value). Plasma astaxanthin concentration mirrored the muscle astaxanthin concentration in the groups of fish fed a diet containing 30 mg kg(-1) astaxanthin. The salmon fed a high astaxanthin and low alpha-TOAc diet had the highest plasma concentration of idoxanthin (P < 0.05). Astaxanthin retention was significantly higher (P < 0.001) in salmon fed 30 mg kg(-1) astaxanthin than in those fed 50 mg kg(-1) astaxanthin, but was not significantly affected by dietary alpha-TOAc. Liver weight, body weight, specific growth rate, feed/gain ratio and mortalities were not affected by dietary alpha-TOAc levels. In conclusion, the dietary addition of alpha-TOAc appears to increase astaxanthin fillet deposition in salmonids and may reduce the demand for astaxanthin supplementation. The effect was rather small and requires verification.

Effect of dietary levels of fat, α-tocopherol and astaxanthin on colour and lipid oxidation during storage of frozen rainbow trout ( Oncorhynchus mykiss ) and during chill storage of smoked trout

Female rainbow trout (Oncorhynchus mykiss) with an initial weight of 0.8–0.9 kg were raised in two experiments including a total of 2550 fish divided into 17 groups. The fish were raised for 6 months on 13 different feeds (four fish groups were replicates) varying in dietary levels of fat (27% or 32%), astaxanthin (40, 70 or 100 mg astaxanthin/kg feed) and vitamin E (α-tocopherol; 100, 300 or 600 mg all-rac-α-tocopheryl acetate/kg feed). The levels of fat, astaxanthin and α-tocopherol in the fillets all increased with increasing dietary levels of each feed component. Furthermore, astaxanthin deposition was found to be significantly improved by increasing the dietary fat level from 27% to 32%, but was not affected by dietary levels of α-tocopherol. The highest deposition of α-tocopherol was found in fish fed the lowest level of astaxanthin (40 mg/kg), whereas α-tocopherol deposition was unaffected by the dietary fat level. Frozen storage (–28 °C) of gutted, cleaned and glazed raw fish for 18 months significantly reduced astaxanthin and α-tocopherol levels, while lipid oxidation, measured as thiobarbituric acid reactive substances (TBARS) was limited. In the first experiment, the highest TBARS levels were found during frozen storage in fish fed the lowest level of astaxanthin (40 mg/kg versus 70 mg/kg or 100 mg/kg); unaffected by dietary levels of α-tocopherol (100 mg/kg versus 600 mg/kg), whereas the dietary astaxanthin level (70 mg/kg versus 100 mg/kg) did not influence lipid oxidation in frozen fish in the second experiment. After brine injection, fillets of fish were smoked and a vacuum-packed (95%), sliced product in a transparent laminate was produced. The quality (pigmentation and lipid oxidation) during 3 weeks of illuminated, chill storage (3 °C) was compared for smoked products produced from fresh fish and from fish stored at –28 °C for 12 months and 18 months. Smoked fillets from fish fed 32% fat were found to be less red than those from fish fed 27% fat, and the astaxanthin content and surface redness of the smoked product decreased during chill storage. Lipid oxidation was pronounced in smoked trout, but a high level of α-tocopherol in the fillet significantly reduced lipid oxidation during chill storage of the smoked product. Lipid oxidation in smoked fillets from fish fed 32% fat was more pronounced than in fish fed 27% fat, but increasing the dietary α-tocopherol level from 300 mg/kg feed to 600 mg/kg feed effectively counteracted the negative effect of the high-fat diet on lipid oxidation in the smoked product. Astaxanthin did not affect lipid oxidation in the chill-stored smoked product, in contrast to the frozen, raw fish. Astaxanthin seems to protect against the very early stages of lipid oxidation, while α-tocopherol is more important as an antioxidant at more advanced stages of lipid oxidation.

Muscle Pigmentation and Plasma Concentrations of Astaxanthin in Rainbow Trout, Chinook Salmon, and Atlantic Salmon in Response to Different Dietary Levels of Astaxanthin

Abstract Pigmentation development was studied in rainbow trout Oncorhynchus mykiss, chinook salmon O. tshawvytscha, and Atlantic salmon Salmo salar fed similar practical diets supplemented with 40, 70, or 100 mg astaxanthin/kg of diet. The initial mean body weights of the respective species were 158, 198, and 191 g. The rainbow trout were reared in freshwater at 6.0–11.3°C, the chinook salmon in seawater at 8.8–14.4°C, and the Atlantic salmon in seawater at 7.1–12.7°C. The response of flesh pigmentation to dietary pigment was most rapid in rainbow trout and slowest in Atlantic salmon. Chinook salmon showed the greatest variation in response to the different dietary concentrations of astaxanthin, followed by rainbow trout and Atlantic salmon. In both rainbow trout and Atlantic salmon, pigmentation was most intense in the distal section and decreased anteriorly. In chinook salmon, pigmentation was most intense in the midsection, followed by the anterior section and then the distal section. Postprandial plas...

Growth and survival of Atlantic salmon, Salmo salar L. fed different dietary levels of astaxanthin. Juveniles

Atlantic salmon, Salmo salar L., juveniles, with a mean initial weight of 1.75 g, were fed casein-based purified diets which had been supplemented with different levels of astaxanthin for a 10-week period. The astaxanthin content of the diets ranged from 0 to 190 mg kg−1 dry diet. The growth and survival of the juveniles were recorded throughout the experiment. The proximate composition, astaxanthin and vitamin A content were determined from whole-body samples at the start and termination of the experiment. The dietary treatment was found to affect growth significantly (P < 0.05). A reduction in the mean weight of the juveniles was observed in the groups fed the diets without astaxanthin supplementation. There was no difference in growth rate between the fish in the groups fed the diets containing 36 or 190 mg astaxanthin kg−1 dry diet, whereas the fish in the group fed the diet containing 5.3 mg astaxanthin kg−1 dry diet had a lower growth rate. There was a tendency to higher survival in the groups fed the diets containing astaxanthin when compared with the groups fed the non-supplemented diets. The moisture and ash contents were significantly lower and the lipid content was higher in the groups fed the astaxanthin-supplemented diets. The astaxanthin and the vitamin A concentrations in the fish were found to be dependent upon the dietary astaxanthin dose; the highest values were found in the fish fed the diet with the highest astaxanthin content. These results strongly indicate that astaxanthin functions as a provitamin A for juvenile Atlantic salmon. The body storage of vitamin A increased in the fish fed the diets containing astaxanthin. However, the increase was low in the fish fed the diet containing 5.3 mg astaxanthin kg−1 dry diet.

Pigmentation of 1, 2 and 3 year old Arctic charr ( Salvelinus alpinus) fed two different dietary astaxanthin concentrations

Two dietary astaxanthin levels (63 and 114 mg kg −1) were fed to three year classes (1 +, 2 +, 3 +) of Arctic charr in a 25 weeks experiment. Growth were monitored, and at weeks 1, 13 and 25, samples were taken for analysis of total carotenoids in flesh, skin, fins and plasma. The average growth rates were 1.35, 0.73 and 0.44% d −1 for the 1 +, 2 + and 3 + charr respectively. In the 3 + group, growth rate declined towards the end of the experiment, and this was probably a result of sexual maturation. Carotenoid concentrations in the flesh and skin increased throughout the experiment for the 1 + and 2 + fish. For the 3 + fish, which became sexually mature, carotenoid concentration in the flesh increased during the early part of the experiment and then stabilized, whereas the concentration in the skin showed a marked increase. After 13 weeks of feeding, there was an overall tendency ( P = 0.066) towards a higher flesh carotenoid concentration in the fish fed the 114 mg astaxanthin kg −1diet than in the fish fed the 63 mg kg −1 diet, but no significant differences were observed at 25 weeks. Significant differences between year classes were seen in flesh, skin and plasma carotenoid concentrations. After 13 weeks of feeding, the flesh carotenoid concentrations were lowest in the 1 + and highest in the 3 + fish. At the end of the experiment, no differences were seen between the 2 + and 3 + fish, while the 1 + fish were still less pigmented. The carotenoid concentrations in skin after 13 and 25 weeks and in fins after 25 weeks were higher in the 3 + fish than in the other groups. Estimates of astaxanthin deposition in relation to body weight increase revealed that the 1 + group was less efficient at utilizing dietary carotenoids for flesh pigmentation than the older fish. The efficiency with which the dietary astaxanthin was used for flesh pigmentation decreased when the concentration was increased from 63 to 114 mg kg −1.

Growth and survival of Atlantic salmon, Salmo salar L., fed different dietary levels of astaxanthin. First-feeding fry

Atlantic salmon fry hatched from pigment-free eggs and from eggs containing the pigment astaxanthin were fed eleven casein/gelatine-based purified diets with varying levels of astaxanthin, ranging from 0 to 317 mg kg−1, to determine the optimum dietary astaxanthin level for satisfactory growth and survival during the start-feeding period. The fish were fed the experimental diets for a period of 11 weeks. No difference in performance was found between the two types of fry originating from the pigment-free eggs and those containing pigment. However, the dietary astaxanthin concentration was found to have a significant effect on both the growth and the survival of fry. Fish fed diets with astaxanthin concentrations below 5.3 mg kg−1 were found to have marginal growth. In addition, mortality was high in the groups fed diets with astaxanthin concentrations below 1.0 mg kg−1. The specific growth rate (SGR) was also affected by the dietary treatment. The lipid content was higher and the moisture content was lower in the fish fed the diets containing astaxanthin concentrations above 5.3 mg kg−1. The vitamin A and astaxanthin concentrations in whole-body samples of the fry were significantly affected by the dietary level of astaxanthin. A plateau level in whole-body vitamin A concentration was observed at dietary levels of approximately 80 mg astaxanthin kg−1 and higher, while no maximum astaxanthin concentration in whole-body samples was observed within the dietary levels used. The results suggest the need for a minimum dietary astaxanthin concentration of 5.1 mg kg−1 to achieve maximum growth and survival during the start-feeding period. The results indicate a low bioavailability of vitamin A palmitate and acetate and the results also suggest a provitamin A function for astaxanthin during the same period.