• Fisheries and Aquatic Sciences
• /
• v.23 no.4
• /
• pp.7.1-7.8
• /
• 2020

Background: To minimize the use of antibiotics and to obtain a more sustainable fish culture and aquaculture industry, development of alternative natural source of immunostimulant to replace antibiotic in aquafeed is highly needed. Objective: Dietary inclusion effect of yacon (YC), ginger (GG), and blueberry (BB) on growth, body composition, and disease resistance of black rockfish against Vibrio anguillarum was compared to ethoxyquin (EQ). Methods: Four hundred eighty juvenile (an initial weight of 4.2 g) fish were randomly distributed into 12 of 50 L flowthrough tanks (forty fish per tank). Four experimental diets were prepared; the control (Con) diet with 0.01% EQ inclusion, and YC, GG, and BB diets at 1% each additive inclusion. Each additive was included into the experimental diets at the expense of wheat flour. Each diet was assigned to triplicate tanks of fish and hand-fed to satiation twice daily for 8 weeks. At the end of 8-week feeding trial, 20 fish from each tank fish were artificially infected by intraperitoneal injection with 0.1 mL of culture suspension of pathogenic V. anguillarum containing 3.3 × 10⁶ cfu/mL respectively. Fish were monitored for the following 8 days after V. anguillarum infection and dead fish were removed every 6 h for the first 4 days and 12 h for the rest of the study. Results: Weight gain, specific growth rate (SGR), and feed efficiency ratio (FER) of fish fed the YC diet was higher than those of fish fed all other diets. However, feed consumption, protein efficiency ratio, and protein retention was not affected by dietary additive. Moisture, crude protein, and crude lipid content of the whole body of fish were affected by dietary additive. Analysis of the Kaplan-Meier survival curves showed that survival of fish fed the YC, BB, and GG diets was higher than the Con diet. Conclusion: Oral administration of YC can improve not only weight gain, SGR, and FER of black rockfish, but lower mortality of rockfish at occurrence of V. anguillarum.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.149-154
• /
• 1999

A 16-week feeding trial was conducted to determine the amount of fish meal analogue (FMA) that can be replacing white fish meal (WFM) protein in Korean rockfish. Five experimental diets were formulated on isonitrogenous and isocaloric basis of $50\%$ crude protein and 15.6 KJ/g diet. The graded level of replacement of PM by Em on the basis of crude protein were as follows : Diet 1($100\%$ WFM), Diet 2($87.5\%$ WFM : $12.5\%$ FMA), Diet 3 ($75\%$ WFM : $25\%$ FMA), Diet 4($75\%$ WFM : $25\%$ FMA+2 EAAs), Diet 5 ($50\%$ WFM : $50\%$ FMA+2 EAAs). Methionine and Iysine were selected for 2 essential amino acids (EAA) to study the effect of adding EAA to the diets 4 and 5. Weight gain (WG), feed fed efficiency (FE) and protein efficiency ratio (PER) of fish fed diet 3, 4 and 5 were significantly lower (P< 0.05) than those of fish fed the control ($100\%$ WFM),while that of fish fed diet 2 was not significantly different diet(P>0.05) from those of fish fed the control diet. WG, FE and PER of fish fed diet 4 were significantly higher (P<0.05) than those of fish fed diet 3, but lower than those of fish fed the control diet. Therefore, these results indicated that FMA protein could substitute WFM protein up to $12.5\%$ without 2 EAAs supplementation in Korean rockfish. And, dietary supplementation of 2 EAAs could be benetficial when FMA is utilized as a fish meal replacer in juvenile Korean rockfish.

• Journal of Aquaculture
• /
• v.9 no.4
• /
• pp.385-394
• /
• 1996

A 15-week feeding experiment was conducted to determine the effects of feeding frequency from 2 different formulated diets on growth, feed efficiency and body composition in juvenile Korean rockfish (Sebastes schlegeli). Duplicate groups of the 30 fish averaging 25 g were fed the control diet containing $58\%$ fish meal and the experimental diet containing $40\%$ fish meal, $10\%$ meat meal, $3\%$ corn gluten meal, $3\%$ soybean meal, and $3\%$ blood meal as protein sources at different feeding frequencies of 2 times daily, once a day in the morning or afternoon, once in 2 days, or given no food. Growth and feed efficiency of the fish were affected by diets (P<0.05), whereas these values were unaffected by feeding frequencies (P>0.05). Feed intake (${\%}$ of body wt.) of the fish fed once in 2 days was lower than that of the fish fed 2 times daily and once a day (P<0.05), Moisture, protein, lipid and ash contents of liver and muscle were not influenced by different diets and feeding frequencies (P>0.05). These results indicate that once a day or once in 2 days feeding regimen must be more effective and economical than that of 2 times daily for juvenile Korean rorkfish.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.5
• /
• pp.643-650
• /
• 1996

A long term feeding trial was conducted to study the effects of different dietary vitamin C levels on growth and its tissue distributions in juvenile Korean rockfish, Sebastes schlegeli. Prior to the start of feeding trial, fish were fed the basal diet supplementing no L-ascorbic acid for four weeks to minimize their body reserves of vitamin C. Then fish were divided into six groups with triplicates and given one of the laboratory semipurified diets supplementing either 0, 25, 50, 75, 150, or 1500 mg L-ascovbic acid (AA)/kg diet $(C_0,\;C_{25},\;C_{50},\;C_{75},\;C_{150},\;&\;C_{1500})$. Fish fed the $C_0$ diet had lower percent weight gain, feed conversion ratio, specific growth rate, and protein efficiency ratio than did fish fed the other diets (P<0.05). After 28 weeks of feeding trial, tissue AA concentrations of fish fed $C_0$ diet were lower than those of fish fed $C_{1500}$ diet (P<0.05). A large amount of total tissue Ah may be reserved in muscle, but the unit AA concentration seemed to be higher in brain than did the other tissues. The growth performances of fish fed $C_{25}$ diet were not different compared to those of fish fed $C_{50}-C_{1500}$ diets (P>0.05), and diet analysis of vitamin C showed that the $C_{25}$ diet had 65 mg AA/kg diet. Therefore, the present long-term study may suggest that the dietary vitamin C requirement is approximately 65 mg AA/kg diet in juvenile Korean rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.2
• /
• pp.252-258
• /
• 1998

A feeding experiment was conducted to investigate the effects of deletion of P, Ca, Zn, Mg, Fe, K, Mn, or Se from mineral premix in the diets containing $40\%$ fish meal on growth performance of juvenile Korean rockfish. Three replicate groups of the fish initially averaging 5.4 g were fed the experimental diets deleted one ot each mineral (P, Ca, Zn, Mg, Fe, K, Mn, Se or all) in the mineral premix for 9 weeks. A basal diet with fish meal ($40\%$), meat meal ($9\%$), soybean meal ($5\%$), corngluten meal ($3\%$), and leather meal ($3\%$) as protein sources were included. Weight gain in fish fed diets deleted Ca, Zn, K, or Se was lower than that of control diet ( P<0.05). Daily feed intake, condition factor, hepatosomatic index and liver chemical composition were not affected by dietary mineral premixes (P>0.05). Apparent skeletal deformities were not observed in the diets deleted each mineral, The data obtained in this study indicate that each of the Ca, Zn, K, or Se should be added in the diet contained $40\%$ fish meal for normal growth of Korean rockfish.

• Journal of Aquaculture
• /
• v.21 no.1
• /
• pp.1-6
• /
• 2008

We determined the effects of dietary supplements for lactic acid bacteria(LAB) such as Lactobacillus brevis(Lb) and Lactobacillus plantarum(Lp) in juvenile rockfish Sebastes schlegeli cultured in flow-through system for 10 weeks. The experimental diets contained $10^4cfu/g,\;10^6cfu/g\;and\;10^8cfu/g$ level each LAB(Lb-4, Lb-6, Lb-8 or Lp-4, Lp-6, Lp-8), respectively. The effects of LAB supplementation was determined by various factor such as weight gain(WG), specific growth rate(SGR), feeding efficiency(FE) and blood assay. For rearing experiment, Lp-8 treatment had significantly high growth rate than control diet treatment. However, all Lb treatment had no significance effect with control diet treatment. In case of the blood assay, hematocrit(Ht) and hemoglobin(Hb) of fish were not affected by LAB supplemental levels. On the other hand, total cholesterol in plasma of Lb-8, Lp-6 and Lp-8 treatments were significantly low than the control diet treatment. We verified the influence of LAB which was originated from species specificity and amount in diet. Consequently, the dietary supplementation as $10^8cfu/g$ level of L. plantarum could be of help for growth enhancement to the juvenile rockfish.

• Proceedings of the Korea Society of Environmental Biology Conference
• /
• 2005.12a
• /
• pp.104-105
• /
• 2005

• Proceedings of the Korea Society of Environmental Biology Conference
• /
• 2005.12a
• /
• pp.106-107
• /
• 2005

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.6
• /
• pp.570-578
• /
• 2012

The present study investigated the effect of diets supplemented with different levels (0, 1, 3, and 5 %) of fig leaf ethanol extract (FLEE) on the nutritional composition of black rockfish Sebastes schlegeli. Fish ($10.05{\pm}0.44g$) were fed to apparent satiation twice daily for 8 weeks. Adding FLEE decreased crude lipid levels and increased crude protein and ash. Among the three organic acids in the whole body of black rockfish, lactic acid was predominant, followed by citric acid and oxalic acid. Five free sugars were found in all groups. Fucose and glucose were the dominant free sugars in the FLEE-added group. The abundant fatty acids in the FLEE-added group were C16:0, C18:1-cis (n9), and C22:6n-3. The major amino acids in the samples were glutamic acid, aspartic acid, glycine, leucine, alanine, lysine, and arginine. The abundant free amino acids in the FLEE-added group were taurine, glutamic acid, alanine, leucine, and arginine.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.5
• /
• pp.617-623
• /
• 2021

The study was conducted to investigate the dietary supplementation of citrus by-product (CBP) and CBP fermented with Bacillus subtilis (BS) or B. pumilus (BP) on growth performance, feed utilization, innate immune responses and disease resistance of Korean rockfish Sebastes schlegelii. Triplicate groups of juvenile fish (initial weight of 22.9 g) were fed one of five experimental diets which were formulated to replace a synthetic vitamin C (L-ascorbyl-2-polyphosphate, LAPP) with CBP or fermented CBP. A basal diet without LAPP and CBP was used as the control diet (Con). At the end of the 13 weeks feeding trial, growth performance, feed utilization and survival of fish fed the Con were significantly lower than those of fish fed the LAPP, CBP and fermented CBP diets. Fish fed the Con were significantly lower in lysozyme activity than fish fed LAPP, CBP and fermented CBP diets. In a challenge test against Edwardsiella tarda, cumulative mortality of fish fed LAPP, CBP and fermented CBP diets was significantly lower (20-30%) than that of the Con (60%). The findings in this study indicate that the CBP and/or fermented CBP can be a promising vitamin C source for LAPP replacement in diet for Korean rockfish.