• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.461-467
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• 2011

This experiment was conducted to determine the each level of a newly developed squid liver powder (SLP) as a dietary protein source replacing fish meal (FM) in juvenile flounder. A diet excluding SLP (FM diet) and a commercial diet were two control diets. Six experimental diets were formulated to replace FM with three types of SLP at 5 and 10% level, respectively (SLP-A5, SLP-A10, SLP-B5, SLP-B10, SLP-C5, SLP-C10). Prior to the start of a feeding trial, fish were fed the commercial diet for 1 week to adjust to the experimental conditions. Fish with average weight of $22.8{\pm}0.40g$ ($mean{\pm}SD$), were randomly distributed to each aquarium as groups of 20 fish and fed the experimental diets in triplicate at satiation for 8 weeks. After 8 weeks, weight gain and specific growth rate of fish fed SLP-C10 was lower than those of fish fed FM diet and SLP-B5. Meanwhile, no significant difference was observed in WG and SGR among fish fed diets excluding SLP-C10. Feed efficiency (FE) and protein efficiency ratio (PER) of fish fed each level of three types of SLP were not different from those of fish fed FM diet. However, fish fed SLP-C5 and SLP-C10 has lower FE and PER than those of fish fed a commercial diet, SLP-A5 and SLP-B5. Therefore, these results indicate clearly that dietary SLP-B could be a good protein source to develop inexpensive commercial diet in juvenile flounder.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.85-93
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• 2014

A 9-week feeding experiment was designed to test the effects of the dietary inclusion of distillers dried grain (DDG) on the growth performance, body composition, and antioxidant activity of juvenile rockfish Sebastes schlegeli. Five isonitrogenous and isocaloric diets were formulated to contain 0% DDG (DDG0), 7% and 14% DDG from rice (diets DDG-R7 and DDG-R14, respectively), as well as 7% and 14% DDG from rice and wheat flour (diets DDG-RW7 and DDG-RW14, respectively). Three replicate groups of juvenile rockfish averaging $68.0{\pm}0.4g$ were fed one of the diets to apparent satiation twice a day. Survival, weight gain, feed efficiency, and the protein efficiency ratio of fish were not affected by dietary DDG (P > 0.05). Proximate and amino acid compositions of the whole body were not affected by dietary DDG (P > 0.05). Plasma total protein, glucose, total cholesterol, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, phospholipid, and triglyceride were not affected by dietary DDG (P > 0.05). Radical scavenging activity on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) in the plasma of rockfish fed the DDG-RW14 diet was higher than that of fish fed the DDG0 diet (P < 0.05). Hydroxyl radical scavenging activity in the liver of rockfish fed diets containing DDG was higher than that of fish fed the DDG0 diet (P < 0.05). Alkyl radical scavenging activity in the liver of rockfish fed the DDG-R7 diet was higher than that of fish fed the DDG0 diet (P < 0.05). These results suggest that DDG is a suitable ingredient for the partial replacement of wheat flour and can be used at a rate of up to 14% in the diet without incurring negative effects on the growth performance or body chemical composition of juvenile rockfish.

• Fisheries and Aquatic Sciences
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• v.20 no.5
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• pp.7.1-7.6
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• 2017

A feeding trial was designed to assess the effects of dietary protein and lipid content on growth, feed utilization efficiency, and muscle proximate composition of juvenile mandarin fish, Siniperca scherzeri. Six experimental diets were formulated with a combination of three protein (35, 45, and 55%) and two dietary lipid levels (7 and 14%). Each diet was fed to triplicate groups of fish ($8.3{\pm}0.1g$) to apparent satiation for 8 weeks. The results showed that growth performance in terms of weight gain (WG) and specific growth rate (SGR) increased with increasing dietary protein level from 35 to 55% at the same dietary lipid level. At the same dietary lipid content, WG and SGR obtained with diets containing 55% protein was significantly higher than those obtained with diets containing 45 and 35% protein. No significant effect on growth rate was found when the dietary level of lipid was increased from 7 to 14%. While the levels of protein and lipid in the diets had no significant effect on feed intake, other nutrient utilization efficiency parameters including daily protein intake (DPI), feed efficiency (FE), and protein efficiency ratio (PER) showed a similar trend to that of growth rates, with the highest values obtained with diets containing 55% protein. Muscle chemical composition was not significantly affected by the different dietary treatments for each dietary lipid or protein level tested. These findings may suggest that a practical diet containing 55% protein and 7% lipid provides sufficient nutrient and energy to support the acceptable growth rates and nutrient utilization of mandarin fish juveniles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.376-382
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• 2018

We investigated the effect of replacing tuna byproduct meal (TBM) and rice bran (RB) with fish meal (FM) and macroalgae (MA) in extruded pellets (EP) supplied as a diet to juvenile Abalone Haliotis duscus in aquaculture. In total, 80,000 juvenile abalone were distributed among eight indoor raceways and supplied with one of four experimental diets. The control diet consisted of FM, fermented soybean meal, corn gluten meal and shrimp meal as protein sources, with wheat flour and dextrin as carbohydrate sources; the control diet also contained MA. In the FM50 diet, TBM was replaced with 50% FM. In the MA 50 diet, RB was replaced with 50% MA. The final diet, FM50+MA50, included TMB and RB in place of 50% FM and 50% MA. Abalone were fed to satiation with little food leftover for 16 weeks. Weight gain and specific growth rate of abalone fed the control diet were greater than those of abalone fed the FM50 and MA50 diets, but not different from those of abalone fed FM50+MA50 diet. The proximate composition of abalone soft body did not vary according to experimental diets. Based on these results, it appears that the traditional commercial diet for juvenile abalone, comprising FM and MA, could be replaced with one containing 50% TBM and 50% RB without any retardation of growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.411-417
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• 2021

By-products produced from medicinal plants (MP) were evaluated as feed additives on growth performance, blood chemistry, and immune responses of the juvenile red lip mullet Liza haematocheila. A commercial diet was used as the control. Four experimental diets were prepared by combining 0.5% of MPs such as Panax ginseng (PG), Schisandra chinensis (SC), Angelica gigas (AG), and Rehmannia glutinosa (RG), via water absorption, to the control diet. Triplicate groups of fish averaging 61.8 g were fed one of experimental diets to apparent satiation for 8 weeks. Dietary supplementation of MPs did not affect the growth performance, biological indices and whole body composition of fish compared to the control. The fish fed with AG diet had an increased weight gain, and specific growth rate compared to fish in SC group. Decreased level of plasma glucose was observed in fish fed diet containing MPs. Lysozyme activity was significantly increased in the fish fed AG diet compared to that of fish in PG group. These results indicate that dietary supplementation of Angelica gigas may enhance growth performance and immune responses in juvenile red lip mullet.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.366-373
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• 2019

The objective of this study was to investigate the utilization of diacylglycerol (DAG) as a new dietary ingredient replacing fish oil in feed for juvenile olive flounder Paralichthys olivaceus. Fish oil based control diet (CON) was prepared and four other diets were formulated by replacing 50% of the fish oil in CON with one of five DAG: DAGL (1,3-lauryl glycerol) or DAGP (1,3-palmityl glycerol) in low or high concentrations (designated as DAGLL, DAGLH, DAGPL and DAGPH). Another diet was prepared replacing 100% of the fish oil in CON with a 1:1 mixture (DAGLP) of DAGL and DAGP. Olive flounder (13.4 g) were fed to apparent satiation, twice a day, for 12 weeks. Following the feeding trials, no significant differences were observed in growth performance, blood parameters and non-specific immune responses between CON and any of the DAG groups. Polyunsaturated fatty acid levels were not significantly affected by the inclusion of DAGs. Thus, DAGL or DAGP could be used to replace up to 50% of fish oil in fish feed without reducing growth performance, health or innate immunity. The replacement of up to 100% of dietary fish oil in olive flounder feed by DAGLP is also feasible.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.2
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• pp.149-158
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• 2019

This study investigated the effects of replacing fish meal (FM) with a mixture of four protein sources (wheat gluten, soy protein concentrate, tankage meal, and poultry byproduct meal) in an extruded pellet (EP) diet for olive flounder Paralichthys olivaceus. Five experimental diets were formulated with alternative proteins replacing 0%, 20%, 30%, 40%, and 50% of FM. Taurine and betaine were added as attractants in the diets. Triplicate groups of fish (initial body weight: $196{\pm}2g$) were fed the diets to apparent satiation. Over the course of a 6-month feeding trial, there were no significant differences between the groups in growth performance, feed utilization, survival, or villus height. The dry matter and protein digestibility of FM50 diet were significantly lower than those of the control diet at water temperatures below $18.5^{\circ}C$ in months 4 and 6. This is a highly significant first report on FM replacement in an EP diet given to olive flounder over a 6-month-long feeding period. It shows that the proper mixture of protein sources can replace up to 50% of FM in olive flounder EP diets with taurine and betaine supplementation. It also shows that 40% of FM could be safely replaced in EP diets during periods of low water temperature.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.350-357
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• 2021

This study aimed to evaluate how fish meal (FM) replacement in diets with a mixture of animal and plant protein sources affect growth performance, feed utilization, hematological parameters and innate immunity of red seabream Pagrus major. A control FM diet was formulated to contain 65% FM (Con). Two other diets were prepared replacing FM in the control diet with a mixture of protein sources (wheat gluten, soy-protein concentrate, tankage meal, and poultry by-product meal) by 30 and 40% (FM30 and FM40, respectively). Total 300 red seabream (body weight, 77.6±0.3g) were distributed to 12 tanks (300 L) in 4 replicates per diet. The fish were fed the diets to apparent satiation for 19 weeks. After the feeding trial, no significant differences could be observed in growth performance, feed utilization, hematological parameters, innate immunity, and survivals among all the dietary treatments. This long-term feeding trial at low water temperature (13.8-17.5℃) indicates that a proper mixture ratio of wheat gluten, soy protein concentrate, tankage meal, and poultry by-product meal can replace FM up to 40% in red seabream diets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.894-899
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• 2020

This study investigated the effects of inclusion of pollock oil (PO) in the diet of broodstock on the egg and larval quality of Walleye Pollock Gadus chalcogrammus. The experimental diet comprised of semi-moist pellets prepared either with or without PO (control; Con). The fish assigned to each diet were fed to visual satiation (two meals per day) for 12 weeks. Eggs spawned from both groups of fish were sampled during the spawning season (three months) and the egg and larval quality was determined. Total egg volume, fertilization, and hatchability of eggs from the PO group were higher than those of the Con group. Fatty acid composition of fertilized eggs was not affected by the experimental diet. Oleic acid, eicosapentaenoic acid, and docosahexaenoic acid content in larvae of the PO group was higher than that in larvae of the Con group. These results demonstrate the beneficial effects of including PO in the broodstock diet of Walleye Pollock, specifically on the quality of the eggs (total egg volume, fertilization, and hatchability) and larvae (fatty acid composition).