• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.342-348
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• 2024

This study evaluated the effects of defatted and non-defatted black soldier fly meal (BSFM) as a fish meal replacement in growing red seabream. Four isonitrogenous and isolipidic diets were formulated: 0% BSFM (D1), 5% defatted BSFM (D2), 5% non-defatted BSFM (D3), and 5% defatted + non-defatted BSFM (1:1, D4). A total of 360 growing red seabreams (mean ± SD body weight, 98.9±0.29 g) were equally distributed into 12 circular polyethylene tanks (1,000 L; 30 fish per tank; N=3 tanks per treatment). The red seabream were fed until satiation twice daily for 12 weeks. After 12 weeks, growth, feed utilization, whole-body proximate composition, blood parameters, and immune related parameters were measured. No significant differences were observed in weight gain, specific growth rate, feed conversion ratio, morphological parameters, plasma metabolites, plasma lysozyme, glutathione peroxidase, and superoxide dismutase among the experimental groups. However, immunoglobulin M (IgM) in fish fed D2 and D3 were significantly higher than those in fish fed D1. Additionally, the fish in D2 group showed higher IgM levels than those in the other treatment groups. These results indicate that defatted and non-defatted BSFM could be utilized as a potential feed ingredient for fishmeal replacement for red seabream.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.546-551
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• 2013

This study examined the effects of the dietary inclusion of Porphyra and sea tangle Laminaria japonica on the growth, feed utilization, body composition, and plasma chemistry of juvenile Korean rockfish Sebastes schlegeli. Eight hundred and forty juvenile fish averaging 5.0 g were allocated 40 fish per tank to 21 180-L flow-through tanks. Seven experimental diets were prepared: control (Con) without additive, 0.5 and 1% Porphyra extract (PE), 3% Porphyra powder (PP), 0.5 and 1% sea tangle extract (STE) and 3% sea tangle powder (STP), referred to as PE-0.5, PE-1, PP-3, STE-0.5, STE-1, and STP-3, respectively. Each additive was included in the experimental diet at the expense of the same amount of wheat flour. Each experimental diet was fed to triplicate groups of fish. The experimental diets had no effect on the survival, weight gain or specific growth rate of the fish, feed consumption, feed efficiency ratio, protein efficiency ratio, protein retention, hepatosomatic index, condition factor, moisture or crude protein content of the entire body excluding the liver or moisture, crude protein or crude lipid content of the liver. None of the plasma parameters were affected by the experimental diets. Based on these results, the dietary inclusion of Porphyra and sea tangle did not affect the growth, feed utilization, body composition or plasma chemistry of juvenile Korean 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.52 no.3
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• pp.247-255
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• 2019

This study was conducted to investigate the effects of extrusion pressure and particle size of feed ingredients on the growth performance and plasma hormone activity in juvenile olive flounder Paralichthys olivaceus. Experimental diets were prepared with extrusion pressure manipulated by screw speed [low pressure (LP), 885 rpm/min; high pressure (HP), 708 rpm/min] and different dietary particle sizes [specific surface area: small (SS), $169.9m^2/kg$; large (LS), $67.4m^2/kg$] in a two-level factorial design. Four experimental diets (LP+SS, LP+LS, HP+SS, and HP+LS) were randomly assigned to 12 tanks (3 replicates) stocked with 20 fish (initial weight, 57 g) per tank. After a 4-week feeding trial, the observable trends of the main effects of extrusion pressure and particle size on growth performance showed that LP and SS enhanced fish weight gain. The plasma insulin-like growth factor-I level was significantly higher in fish fed the LP+SS diet than in fish fed the HP+SS diet. These results indicate that manipulation of the physical qualities of feed through adjustment of extrusion pressure and feed ingredient particle size may influence the growth performance of juvenile olive flounder, which should be considered in feed manufacture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.3
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• pp.319-327
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• 2022

An eight-week feeding trial was conducted to evaluate the effects of a diet consisting of different onion juice processing by-product (OJPB) levels on juvenile black rockfish Sebastes schlegelii growth, feed utilization, and, lysozyme and antioxidant enzymes activities. Juvenile rockfish (2.2 g) were randomly distributed into 15 flow-through tanks (30 fish/tank). Five experimental diets were prepared in triplicate. The experimental diets were supplemented with OJPB at different levels of 0 (control), 0.25, 0.5, 0.75 and 1% (designated as OJPB0, OJPB0.25, OJPB0.5, OJPB0.75 and OJPB1, respectively). At the end of the feeding trial, the results revealed that the fish that were fed the OJPB0.75 and OJPB1 diets showed enhancement in growth (weight gain and specific growth rate) and feed utilization (feed efficiency and protein efficiency ratio) compared with the fish that were fed other diets. Plasma lysozyme, glutathione concentration, and superoxide dismutase and catalase activities significantly increased in the fish that were fed the OJPB0.75 and OJPB1 diets. In conclusion, dietary supplementation of 0.75-1% OJPB in juvenile rockfish diet improved the growth performance and antioxidant status.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.194-202
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• 2003

Budgets for water, nitrogen, and chemical oxygen demand (COD) were determined in two 0.012 ha earthy-bottom ponds stocked with Israeli strain common carp at an initial stocking density of $20\;fish/m^3$. Total ammonia nitrogen (TAN) concentrations increased continuously but later decreased in pond A as a consequence of high nitrification. COD concentrations increased during the experimental period due to the accumulation of feed input. Nutrient budgets showed that feed represented $94-95\%$ of nitrogen input and about 99% of organic matter input. Fish harvest accounted for $40\%$ of nitrogen and organic matter input. Seepage and water exchange removed $15-17\%$ of nitrogen input but only $1-2\%$ of organic matter. Draining of the ponds removed $20-26\%$ of input nitrogen, mostly in inorganic forms, but removed only minus organic matter. Fish and water column respiration accounted for $39\%$ of organic matter input, and benthic respiration accounted for $7-12\%$ of organic matter input. No significant change of nitrogen and organic matter in both pond bottoms were found during the three-month growth period. The unrecovered input nitrogen, about $6.3-13\%$, was lost through denitrification and ammonia volatilization. On a dry matter basis, fish growth removed $31\%$ of total feed input and left $69\%$ as metabolic wastes.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.94-101
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• 2007

The status of recently expanded exotic pangasiid catfish Pangasius hypophthalmus, Pangasiidae farming in rural Bangladesh has been studied for finding research needs, through knowing the culture methods, associated activities and problems, to make the farming sustainable. Data were collected using participatory rural appraisal (PRA) tools in nine villages in three upazilas (sub-district) of Mymensingh district. The farmers have not got any formal training and have developed their knowledge on farming the fish through practice over years and sharing of knowledge among fellow farmers. Linked industries, e.g. hatcheries, nurseries, feed mills, trading of feed and fish etc. have developed that created employment opportunities. Most of the farmers produce two crops a year. About 90% of the farmers were found to practice mono culture of pangasiid catfish at high stocking density. The feeding rates started from 10-15% of the body weight per day at fingerling stage that reduced to 4-6% with growth. The average yield was found to be 25 tonslha/year. The livelihood of the farmers has been improved through farming the fish. Women and children were rarely engaged in the activities. The identified major problems in farming the fish were water quality deterioration, high feed costs and declining consumer demand and market price.

• Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.58-68
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• 2023

This study was conducted to determine dietary threonine (Thr) requirement for juvenile olive flounder (Paralichthys olivaceus). A total of 450 juvenile fish (23.2 ± 0.4 g) were randomly distributed to 18 tanks (215 L) with 25 fish per tank. Experimental diets included with graded levels of Thr at 0.0%, 0.4%, 0.8%, 1.2%, 1.6%, and 2.0% were assigned for triplicate groups of fish and fed two times daily to apparent satiation for 12 weeks. Weight gain, specific growth rate, feed intake, feed utilization and survival were significantly (p < 0.05) increased in fish fed with dietary Thr levels over 0.8%, and no significant differences were observed between 0.8% to 2.3% levels. Non-specific immune parameters of serum lysozyme, myeloperoxidase activity, antiprotease activity, and total immunoglobulin were significantly increased by dietary Thr over 0.8%. Based on the broken-line regression analysis, the Thr requirement for the optimum growth and immune response in olive flounder is likely to be 1.03% in the diet.

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.122-126
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• 2002

A feeding trial was conducted to determine compensatory growth of juvenile olive flounder in the spring. Five treatments of fish with 3 replicates were prepared: the control group fish (C) fed twice daily for 8 weeks, the Sl, S2, S3 and S4 fish fed for 7, 6, 5 and 4 weeks after 1, 2, 3 and 4 weeks of starvation, respectively. Survival of olive flounder was not significantly different among treatments. Weight gain of flounder in S2 was significantly (P<0.05) higher than that of fish in S3 or S4, but not significantly different from that of fish in C or Sl. The poorest weight gain was observed in fish of S4 treatment. Specific growth rate (SGR) for flounder in S2 was significantly (P<0.05) higher than that for fish in C or S4, but not significantly different from that of fish in Sl or S3. Feed intake (g/fish) was proportional to duration of days of feeding except for flounder in S2, but not significantly different among C, Sl or S2. Feed efficiency ratio (FER) and protein efficiency ratio (PER) for flounder in S2 were significantly (P<0.05) higher than for fish in C, but not significantly different from those for fish in Sl, S3 or S4. Hepatosomatic index (HSI) and condition factor (CF) for flounder in Sl, S3 and S4 were not significantly different from those for fish in C, but significantly (P<0.05) lower than S2 except for CF in Sl at the end of the experiment. Proximate composition of the whole body of flounder was not significantly different among treatments. In considering results of the experiment, juvenile olive flounder achieved compensatory growth when properly fed after starved up to 2 weeks in the spring. Compensatory growth of fish was supported by improvement in SGR, FER and PER in fish starved.

• Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.38-42
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• 2005

We evaluated the effects of different feeding strategies on the growth of young Nile tilapia, Oreochromis niloticus L., in a freshwater recirculating system during summer. Each of twenty fish (Mean body weight$\pm$ SD; 37. 7$\pm$0.10 g) were randomly distributed into each of 24 tanks. Eight treatments were prepared in triplicate. Control fish were hand-fed commercial feed twice daily without starvation. The other seven treatments employed different feeding and starvation strategies ranging from I day starved and 1 day fed (1DS+ 1DF) to 7 days starved to 7 days fed (7DS+7DF). All fish survived to the end of the 44-day feeding trial. The amount of food supplied was highest for the control fish in the control. Food supplied to fish in the 3DS+3DF and 4DS+4DF treatments was significantly lower than that of fish in the 1DS+1DF and 2DS+2DF treatments, but significantly higher than that of fish in the 5DS+5DF, 6DS+6DF and 7DS+7DF treatments. The weight gain of control fish was significantly higher than that of fish in other treatments. Feed efficiency ratio (FER) for fish in the 7DS+7DF treatment was significantly higher than that of fish in the control group, but it did not differ from that of fish in the 1DS+1DF and 2DS+2DF treatments. We concluded that young Nile tilapia raised with different starvation and feeding regimes during the summer in a freshwater recirculating system did not catch up in growth to fish fed daily. However, the enhanced FER of Nile tilapia in the 7DS+ 7DF, 2DS+ 2DF, and 1 DS+ I DF treatments partly explains the compensatory growth of the fish, although their weight gain was relatively low.