• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.5
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• pp.477-492
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• 1993

In order to investigate the n-3 highly unsaturated fatty acids (n-3HUFA) requirement of the Korean rockfish Sebastes schlegeli, two experiments were conducted in the flush-out aquarium system. 1. Effects of different dietary fatty acids on growth and feed efficiency Efficacy of different fatty acids on the Korean rockfish was investigated by feeding diets containing each of the different fatty acids, 12:0, 18:1n-9, 18:2n-6, 18:3n-3, and n-3HUFA for 9 weeks. The best growth and feed efficiency were obtained from the fish fed diet containing n-3HUFA (P<0.05). 2. n-3HUFA requirement Requirement of dietary n-3HUFA for the Korean rockfish (5.9 g in mean body weight) was investigated with the test diets containing different levels of n-3HUFA ranging from $0\%$ to $4.0\%$ at $8\%$ dietary lipid level. After 6 weeks of feeding experiment, fish performance and fatty acid composition of liver were studied. Growth was significantly improved with increasing dietary n-3HUFA level up to the $0.9\%$ in the diet (P<0.05). Higher values of lipid content, 18:1/n-3HUFA ratio of polar lipid of liver and hepatosomatic index were observed in the fish fed n-3HUFA deficient diets. The groups of fish fed lower levels of dietary n-3HUFA showed higher 18:1 and love. n-3HUFA (EPA+DHA) levels in polar lipid of the liver. The data obtained in these experiments indicated that dietary n-3HUFA was essential for the Korean rockfish, and required level of n-3HUFA was around $0.9\%$ in diet.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.118-126
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• 2010

A feeding trial was conducted to investigate the effects of different levels of dietary n-3 highly unsaturated fatty acids (HUFA) (1.1-5.6%) and vitamin E (70 and 400 mg/kg) on the growth and body composition of juvenile rockfish. Six isonitrogenous (45% crude protein) and isolipidic (17% crude lipid) diets were formulated to contain graded levels of n-3 HUFA and vitamin E. Diets 1, 2 and 3 consist of 400 mg vitamin E/kg diet with graded levels of 1.1, 3.0, and 5.6% n-3 HUFA, respectively. Graded levels of n-3 HUFA (1.1, 3.0, and 4.0%) were added in diets 4, 5 and 6, respectively, containing 70 mg vitamin E/kg diet each. At the end of feeding trial, growth performance of rockfish was affected by neither dietary n-3 HUFA nor vitamin E levels. Feed efficiency and hepatosomatic index were slightly decreased (P<0.05) with increment of dietary n-3 HUFA at each dietary vitamin E level. Dietary vitamin E and n-3 HUFA levels did not affect proximate composition and vitamin E concentration in the dorsal muscle of rockfish. Liver moisture and crude protein contents positively related to dietary n-3 HUFA levels. Liver lipid content and hematocrit value were significantly decreased (P<0.05) by increasing dietary n-3 HUFA levels. Eicosapentaenoic acid (20:5n-3; EPA) and docosahexaenoic acid (22:6n-3; DHA) concentrations in the dorsal muscle significantly correlated to dietary n-3 HUFA levels, except for fish fed the diet 6 containing 4% n-3 HUFA and 70 mg vitamin E/kg diet. EPA concentration in the dorsal muscle of fish fed the diet 6 was significantly lower than that of fish fed the diets 2, 3 and 5. The present findings suggest that feeding of diets containing excessive n-3 HUFA level with varying addition of vitamin E may alter fatty acid composition in the dorsal muscle, but do not affect growth of juvenile rockfish.

• Journal of Aquaculture
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• v.13 no.3
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• pp.207-213
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• 2000

Five diets, containing different levels (0.3-1.5%) of n-3 highly unsaturated fatty acids (n-3HUFA) adjusted by adding different ratio of squid liver oil and soybean oil to 8% lipid, were fed to the rockfish (130 g) for 8 weeks. Mean weight gain and feed efficiency were lowest in the fish fed the diet containing 0.3% n-3HUFA. These values improved with increasing squid liver oil, and showed linear relation up to 0.6% n-3HUFA, Using the brocken line model, the dietary n-3HUFA requirement was estimated as about 0.9 % for optimal weight gain of the fish. Crude lipid levels of the liver in 0.3-0.6%) n-3HUFA diets were significantly higher than in the 1.5% n-3HUFA diet (P<0.05). Fatty acid composition of polar lipid in the liver were directly affected by dietary lipid sources. The level of n-3HUFA of polar lipid in the liver increased with dietary n-3HUFA levels, although 18:2n-6 content decreased. Hence the n-3HUFA requirement of a growing rockfish is 0.6-0.9% of diet.

• Journal of Aquaculture
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• v.6 no.2
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• pp.89-105
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• 1993

In order to investigate the effects of dietary n-3 highly unsaturated fatty acids (n-3HUF A) levels on growth and body composition of the Korean rockfish, six experimental diets with various levels of n-3HUFA, which were adjusted by adding squid liver oil and/or soybean oil at $8\%$ dietary lipid level, were fed to the Korean rockfish (6.2g in mean body weight) for 10 weeks. Daily weight gain, feed efficiency and nutrient retention efficiency were the lowest in the fish fed a diet containing 0% n-3HUFA. These parameters were effectively improved by supplementation with n-3HUFA, and showed linear increase up to $1.2\%$ dietary n-3HUFA level (P<0.01). There was no additional response above this level. A higher concentration of nonpolar lipids in the liver was observed for the fish fed insufficient levels of n-3HUFA in the diets. However the liver glycogen content and hepatosomatic index were slightly deareased. The lipid contents of the whole body and vicera showed significantly higher in the fish fed sufficient levels of n-3HUFA in the diets (P<0.05). The fatty acid compositions of polar lipids in the whole body and liver were affected by dietary fatty acid compositions. The contents of n-3HUFA and 18:1 in the liver increased with increasing the n-3HUFA level in the diets, while the 18:2n-6 and 18: 3n-3 decreased. These results suggest that n-3HUFA plays an essential role for normal growth of the Korean rockfish, and the requirement of n-3HUF A is around $1.2\%$ of the diet.

• Journal of Aquaculture
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• v.9 no.4
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• pp.353-361
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• 1996

The objective of this study was to investigate the essential fatty acids requirement and its optimal level in dietary for young of tiger puffer. The young puffer fish used in feeding trial were average body weight 3.45g. Fish were randomly divided into 11 groups containing 30 fish each in 200 ${\ell}$ tank and reared for 8 weeks at ambient temperature. In basal diets, defatted squid meal, casein-Na and activated gluten were used as the dietary protein source, dextrin and ${\alpha}$-starch (gelatinized starch) as the digestible carbohydrate source and beef tallow as the lipid source. Five fatty acids added to diet were linoleic acid (LNA), linolenic acid (LNA), eicosapentaenoic acid (EPA) ,docos-ahexaenoic acid (DHA) and n-3 HUFA. Among that, the supplement of LA and LNA were $1\%$ of total composition of diet, respectively, and EPA, DHA and n-3 HUFA ranged from $0.3\~1\%$ level. Growth and feed efficiency were measured to the interval of 2 weeks, and analyzed fatty acids composition of diet and liver by GCL. As a result of 8 weeks experiment, predominant growth were shown in $0.5\~1\%$ n-3 HUFA and $0.5\%$ DHA than others (P<0.05). In comparison of efficiency among EPA, DHA and n-3 HUFA groups, the most results were revealed in n-3 HUFA and the least in EPA. The adding effect was shown in EPA by increasing the fatty acids content from 0.5 to $1\%$ in diet. However, sudden decline and steady state in growth were observed in $1\%$ DHA and $1\%$ n-3 HUFA, respectively. The feeding efficiency and protein efficiency ratio were high in n-3 HUFA groups and $0.5\%$ DHA. Consequently, it is assumed that young puffer requires n-3 HUEA both EPA and DHA as essential fatty acids. The optimal content in diets are about $0.5\%$ of HUFA or DHA.

• Journal of Aquaculture
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• v.6 no.2
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• pp.107-123
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• 1993

To define the effects of various levels $(0\~1.5\%)$ of dietary n-3HUFA on the physiological changes in the Korean rockfish, variations in blood variables and hepatocytes were studied. Biochemical serum analyses, lactate dehydrogenase (LDH) activity of the liver cytosol and ATPase activity of the liver microsomal membrane were also studied. The haematological values (red blood cell, hemoglobin, hematocrit, MCHC, MCV and MCH) were not significantly different in the experimental groups $(P\geq0.05)$. The total protein and glucose levels in the serum were affected by dietary n-3HUFA levels. These levels in groups fed n-3HUFA insufficient diets were significantly lower than those of n-3HUFA sufficient groups (P<0.05). Serum levels of total cholesterol, free cholesterol, glutamic pyruvic transaminase (GPT) and glutamic oxaloacetatic transaminase (GOT) showed significantly higher values in the fish fed n-3HUFA deficient diets (P<0.05). The LDH in the serum was dropped with increasing dietary n-3HUFA levels, but the LDH activity of the liver cytosol was elevated. Histologically, the hepatic cell in the fish fed n-3HUFA free diet was abnormal and showed a necrotic condition. $Ca^{2+}-ATPase$ activities of the liver microsomal membrane were significantly lower in the fish fed n-3HUFA deficient diets than in those fed n-3HUFA sufficient diets (p<0.005). These results suggested that the liver cell membrane was affected by dietary fatty acid compositions and cell membrane of the fish fed n-3HUFA insufficient diets showed abnormalities.

• Journal of Aquaculture
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• v.6 no.3
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• pp.199-211
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• 1993

In order to elucidate the effect of dietary n-3 highly unsaturated fatty acids (n-3HUFA) on the changes of body weight and chemical compositions in the Korean rockfish during starvation, the fish were not fed for 9 weeks after fed different levels $(0\~1.5\%)$ of n-3 HUFA for 10 weeks. The higher level of n-3HUF A was contained in the diets, the slower body weight loss was resulted (P< 0.05). The decreasing rates of the body nutrients of the fish were significantly higher in the fish fed n-3HUF A deficient diets than those of the fish fed n-3 HUF A sufficient diets. Protein and lipid contents of the whole body were decreased with starvation whereas moisture content was increased. Decrease of lipid was mainly due to the decrease of nonpolar lipid. Amounts of polar lipid in the whole body were almost constant throughout the starvation, meaning not being affected by dietary n-3HUF A levels. Percentage of 22: 6n-3 was increased in the polar lipid fraction, but monoenic acids (16:1, 18:1), n-3 series (18:3, 18 4, 20:4) and n-6 series (20:2, 22:4, 22:5) were decreased with starvation. Fatty acid compositions of nonpolar lipid were not changed with starvation. These results suggest that all fatty acids of nonpolar lipid are equally utilized for energy during starvation.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.78-79
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• 2003

Effects of dietary lipid level and source (squid liver oil being rich in n-3 HUFA, soybean oil being rich in 18:2n-6, and linseed oil being rich in 18:3n-3) in fishmeal-based diet on growth and body composition of grower sunshine bass raised in seawater were investigated. Fifteen grower (an initial weight of 146.8$\pm$0.23 g) sunshine bass were randomly distributed into 27 of 250 L fiber reinforced plastic flow-through tanks. Fish were hand-fed to satiety twice daily for 6 days a week throughout the feeding trial. Survival was over 97% and not significantly affected by either dietary lipid level or lipid source (n-3 highly unusaturated fatty acid, HUFA). Weight gain of fish tended to improve with dietary n-3 HUFA level up to 2.9%, but sharply decreased at 3.5%. The best weight gain was obtained in fish fed the diet supplemented with 6% squid liver oil and 3% soybean oil. FER and PER were not significantly affected by either dietary lipid level or dietary lipid source. The lowest moisture content of the whole body was observed in fish fed the diet supplemented with 12% squid liver oil and highest for the diet supplemented with 9% linseed oil, respectively. Protein content of fish was not significantly affected by either dietary lipid level or dietary lipid source. However, lipid content of the whole fish tended to increase with an increase of either dietary lipid level or dietary n-3 HUFA level, except for fish fed the diet supplemented with 9% linseed oil. Ash content of fish fed the diet with no supplementation of oil was highest and lowest for the diet supplemented with 9% soybean oil, respectively. Significant differences in saturated fatty acids (16:0, 18:0 and 24:0), monoene (18:1n-9), 18:2n-6, 20:5n-3 and sum of n-3 HFUA of fish were observed. In considering these results, it could be concluded that supplementation of 9% oil combined with 6% squid liver oil and 3% soybean oil into fishmeal-based diet was the most recommendable for growth of grower sunshine bass raised in seawater.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.49-58
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• 2019

This study was conducted to investigate the effects of different dietary lipid sources on the growth, feed utilization, body composition and tissue fatty acid profile of olive flounder Paralichthys olivaceus. Five isonitrogenous and isocaloric diets were formulated by adding various lipid sources including soybean oil (SO), eicosapentaenoic acid triglyceride (EPATG) and ethyl ester (EPAEE) forms, docosahexaenoic acid triglycerides (DHATG) and a 1:1 blend of soybean oil and DHATG. Triplicate groups of fish ($6.8{\pm}0.01g$) were fed one of the experimental diets to apparent satiation twice daily for 8 weeks. Fish fed the DHATG diet had the highest growth, protein efficiency ratio and feed efficiency values which were significantly higher than those fed the SO and EPAEE diets. Whole body proximate composition and somatic parameters were not influenced by the dietary treatments. Muscle of fish fed with SO diets were rich in 18:1n-9, 18:2n-6 and 18:3n-3, whereas those of fish fed with EPATG, EPAEE and DHATG diets were rich in n-3 highly unsaturated fatty acids (HUFA). These findings indicated that the inclusion of n-3HUFA oils in olive flounder feed could be beneficial for the fish while simultaneously increasing the concentration of beneficial n-3HUFA in fish fillets destined for the human consumer.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.123-130
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• 2014

Three types of artificial microparticle diets were developed for rotifer (Brachionus plicatilis) enrichment. The efficacies of enrichment with the artificial diets were evaluated and compared to those with commercial enrichment diets on the growth and survival of flounder larvae. Total lipid content was highest in the rotifer enriched with oil capsule (40.5% in dry weight). The n-3 highly unsaturated fatty acid (n-3 HUFA) content was also highest in the rotifer fed with oil capsule (7.08% in dry weight). The flounder larvae fed on the rotifer enriched with oil capsule showed the highest growth compared to those fed on any other enriched rotifer (P<0.05). The survival ratio of flounder larvae fed on the rotifers enriched with oil capsule and emulsion oil were higher than those fed on any other enriched rotifer (P<0.05). From the feeding study, the growth and survival of flounder larvae were enhanced by feeding rotifer enriched with oil capsule compared to rotifer enriched with any other diets. The rotifer fed on oil capsule containing high contents of n-3 HUFA. Therefore, a significant relationship between the growth and survival of flounder larvae and the n-3 HUFA content of rotifer could be obtained.