• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.5
• /
• pp.577-581
• /
• 2014

The aim of this study was to investigate the effect of diet extruder conditions, such as feed-loading rate and screw speed, on growth performance and biochemical responses in olive flounder Paralichthys olivaceus. Over 8 wks, we used four identical diets (triplicated per treatment) with differing ratios of feed-loading rate (kg/h):screw speed (rpm/min) in a laboratory-scaled twin-screw extruder of 50:640, 80:640, 120:640, and 80:400, designated as EP1, EP2, EP3, and EP4, respectively. Screw speed impacted the buoyancy of experimental diets. Diets produced at a screw speed of 640 rpm/min floated for > 24 hrs, whereas those produced at a speed of 400 rpm/min sank between 10 s and 5 min. Fish that were fed EP1 and EP4 diets grew significantly faster than those fed EP2 and EP3 diets. Fish fed EP1 diets ate and gained weight most efficiently among treatments, a result that is likely to be related to feed-loading rate, i.e., ingredients extruded at a low feed-loading rate may have more time to cook in the pre-conditioner of the extruder. A cooked diet may be easier to digest in fish. Fish fed EP4 diets also showed significant weight gain, as compared to those fed EP2 and EP3 diets. However, we found no differences among treatments in proximate compositions of dorsal muscle, liver, and viscera of fish. Our results suggest that extruder conditions, may influence feed quality, impacting feed efficiency and growth of fish.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.4
• /
• pp.407-412
• /
• 2013

We performed four sets of feeding trials to establish optimum feed size (Exp-I), stocking density (Exp-II) and feeding frequency (Exp-III and IV) for Korean rockfish. In Exp-I, three different particle sizes of a commercial diet (small, 2.0-2.1 mm; medium, 2.4-3.2 mm; and large, 4.0-5.3 mm) were fed to four replicate groups of fish ($22.8{\pm}0.1g$), each of which was fed to apparent satiation for six weeks. In Exp-II, fish ($44.3{\pm}0.4g$) were reared at four stocking densities (1.5, 3.0, 4.5 and 6.0 $kg/m^3$) and fed a commercial diet to apparent satiation for four weeks. In Exp-III, fish ($14.8{\pm}0.1g$) were fed a commercial diet once, twice, thrice, $4{\times}$ or $5{\times}$ a day at a feeding ratio of 3.25% of body mass. Another group of fish was fed the same commercial diet $5{\times}$ a day to apparent satiation; this treatment was designated FS (five times satiation/day). In Exp-IV, fish ($31.3{\pm}0.1g$) were fed a commercial diet once, twice, thrice or $4{\times}$ a day to apparent satiation. Another group of fish was fed to apparent satiation once every 48 hours. In Exp-I, fish fed the large particle (4.0-5.3 mm) diet had a significantly higher feed conversion ratio and lower protein efficiency ratio than fish fed the small particle diet. In Exp-II, groups of fish reared at densities of 4.5 and 6.0 $kg/m^3$ had significantly higher feed intake and growth performance than fish reared at 1.5 and 3.0 $kg/m^3$. In Exp-III, fish fed to apparent satiation had significantly higher growth performances than fish fed once or $4{\times}$ a day. A significantly higher feed conversion ratio and a lower protein efficiency ratio were obtained in the FS group. In Exp-IV, growth performance and feed utilization efficiency were not significantly affected by experimental variation in feeding frequency. Fish fed to apparent satiation once every 48 hours had better feed utilization than those in other treatments and growth performances of those were comparable. Therefore, the optimum feed particle size, stocking density and feeding frequency for Korean rockfish under conditions we used were 2.0-3.2 mm, 4.5-6.0 $kg/m^3$, and once a day or once every 48 hour, respectively.

• Fisheries and Aquatic Sciences
• /
• v.22 no.10
• /
• pp.23.1-23.10
• /
• 2019

Background: Taurine is a conditional essential amino acid for fish. A study was conducted to investigate the compensating effect of supplemental taurine in diets for red seabream (Pagrus major) on impaired growth performance by fish meal (FM) replacement with soybean meal (SM) at low water temperature (14.15 ± 1.95 ℃). Methods: A FM-based diet was considered as a high FM diet and three other experimental diets were formulated to replace FM with SM by 20, 35, or 50% (HFM, SM20, SM35, or SM50, respectively) without taurine and other four diets were formulated by adding 1% taurine to the diets (HFM-T, SM20-T, SM35-T, or SM50-T, respectively). Triplicate groups of fish (108.9 ± 1.58 g/fish) were distributed into 24 polyvinyl circular tanks (215 L) with 20 fish per tank and fed one of the diets to satiation for 20 weeks. Results: Growth performance and feed utilization of red seabream were significantly improved by the dietary taurine supplementation. SM20-T and SM35-T diets increased fish growth that are comparable to HFM diet. Feed intake, feed conversion ratio, and protein efficiency ratio of fish fed SM20-T and SM35-T diets were not significantly different from those of HFM group. Dietary taurine supplementation in each FM replaced group numerically increased innate immunity of the fish. Lysozyme and superoxide dismutase activities were significantly decreased in fish fed SM35, SM50, and SM50-T diets compared to those of fish fed HFM diet while they were not significantly lower in SM20, SM20-T, SM35, and SM35-T groups. Glutathione peroxidase activity was significantly lower in fish group fed SM50 diet while SM50-T group did not significantly lower compared to that of HFM group. The relative expression level of hepatic IGF-1 mRNA was improved in fish fed taurine-supplemented diets compared to their respective SM diets. Conclusions: Growth performance and feed utilization of red seabream can be accelerated or restored by 1% taurine supplementation when they are fed high level of SM up to 35% in diets during low water temperature season.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.4
• /
• pp.320-324
• /
• 2010

We investigated the proper feeding frequency and satiation rate for the growth of red- and white-colored carp fingerlings in a feeding experiment. Triplicate groups of fish averaging 6.3 g were fed diets at four feeding frequencies (1, 2, 3, or 4 meals a day) and two satiation rates (satiation and 80% satiation) for 6 weeks. The survival of the fish was not affected by either the feeding frequency or the satiation rate. The weight gain, feed efficiency, and protein efficiency ratio of fish were affected by the feeding frequency and satiation rate, and increased significantly with both. The feed efficiency and protein efficiency ratio with satiation feeding of fish fed four meals a day did not differ from those of fish fed three meals a day. The daily feed intake was affected by the feeding frequency and satiation rate. The moisture, crude lipid, and ash contents of whole body were affected by the feeding frequency. Moisture and crude lipid contents were affected by feeding satiation. Based on these results, we conclude that the proper feeding frequency and satiation rate for the optimum growth of red- and white-colored carp fingerlings is four meals a day with satiation feeding.

• Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.311-315
• /
• 2011

A 7-week feeding trial was conducted to investigate the effect of dietary starch level and kind on the growth and body composition of juvenile olive flounder. Triplicate groups of fish (average weight: 1.5 g) were fed iso-nitrogenous (48% crude protein) and isocaloric (4.8 kcal/g diet) diets containing 15-25% ${\alpha}$-potato starch and 15% ${\beta}$-potato starch. Survival was not affected by dietary starch level and kind. The weight gain of fish fed the diet containing 20% ${\alpha}$-potato starch was significantly higher than that of fish fed the diets containing 15% and 25% ${\alpha}$-potato starch levels. The feed efficiency and protein efficiency ratios of fish fed the diets containing 15% ${\beta}$-potato starch were significantly lower than those of the other groups (P < 0.05). The protein efficiency ratio tended to increase with increasing ${\alpha}$-potato starch. The daily feed intake of fish fed the diet containing 15% ${\beta}$-potato starch was significantly higher than that of the other groups (P < 0.05). The hepatosomatic index, condition factor, and proximate composition of the whole body were not affected by the dietary starch level and kind. These results indicate that up to 20% ${\alpha}$-potato starch could be incorporated into the juvenile flounder diet for optimum growth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.4
• /
• pp.377-383
• /
• 2013

We ran a feeding trial to determine optimal dietary protein and lipid levels for growth of juvenile long snout bullhead Leiocassis longirostris Gunther. Eight experimental diets (P20L7, P20L14, P30L7, P30L14, P40L7, P40L14, P50L7 and P50L14) were formulated to contain 20%, 30%, 40% or 50% protein combined with either 7% or 14% lipid. Three replicate groups of fish (mean mass: 3.9 g/fish) were fed one of the experimental diets ad libitum for 8 weeks. Survival of fish fed the P20L14 diet was lower than that of fish fed the P40L14, P50L7 and P50L14 diets. Growth of fish fed diets containing 7% lipid increased with increasing protein level (up to 50% protein); growth of fish fed diets containing 14% lipid increased with increasing protein level (up to 30% protein). The feed efficiency of fish fed a diet with 50% protein and 7% lipid was higher than that of other groups. Whole body moisture and lipid contents were affected by dietary lipid level but not by dietary protein level. The crude lipid contents of fish fed 14% lipid diets were higher than those fed 7% lipid diets across all protein levels (other than the 50% level). Thus, under our experimental conditions, an increase in dietary protein level improved growth and feed efficiency of fish; a diet containing 50% protein with 7% lipid was optimal for growth and effective feed utilization in juvenile long snout bullhead.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.5
• /
• pp.343-345
• /
• 2008

This study determined the optimum feeding frequency for the growth of juvenile cherry salmon (Oncorhynchus masou). Triplicate groups of fish (initial mean weight 19.1 g) were fed extruded pellets at four feeding frequencies for 50 days: once every 2 days, once a day, twice a day, and three times a day. The mean water temperature during the feeding trial was $17.9{\pm}1.59^{\circ}C$. The survival of all groups was 100%. The final fork length of fish fed twice a day was significantly greater than that of the other groups (P<0.05). The weight gain of fish fed two and three times daily was significantly greater than that of fish fed once a day or every 2 days (P<0.05). The daily feed intake increased significantly with feeding frequency (P<0.05), but there was no significant difference in the weight gain of fish fed two or three times a day. The feed efficiency of fish fed once every 2 days was highest (P<0.05), and the feed efficiency of fish fed two or three times a day was significantly higher than that of fish fed once a day (P<0.05). The results of this study indicated that the optimum feeding frequency for the growth of juvenile cherry salmon is twice a day, while the feeding efficiency of fish fed once every 2 days was best.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.9
• /
• pp.1320-1328
• /
• 2013

Three experiments were conducted to evaluate the ME value, standardized ileal digestibility (SID) of amino acids (AA) of fish meal, and the effects of single cell protein (Prosin and Protide) replacing fish meal in diet on growth performance, nutrient digestibility and intestinal morphology in weaned piglets. In Exp. 1, twenty-four barrows with initial BW of $30.8{\times}2.6kg$ were allotted to one of four dietary treatments. Diet 1 contained corn as the only energy source. The other three diets replaced 20% of the corn in diet 1 with one of the three protein feeds (fish meal, Prosin and Protide), and the DE and ME contents were determined by difference. In Exp. 2, eight barrows (initial BW of $25.6{\pm}3.2kg$) were fitted with ileal T-cannulas and allotted to a replicated $4{\times}4$ Latin square design. Three cornstarch-based diets were formulated using each of the protein feeds as the sole source of AA. A nitrogen-free diet was also formulated to measure endogenous losses of AA. In Exp. 3, one hundred and eighty piglets (initial BW of $7.95{\pm}1.59kg$) weaned at $28{\times}2d$ were blocked by weight and assigned to one of five treatments for a 28-d growth performance study, each treatment was fed to six pens with six pigs (three barrows and three gilts) per pen. The five treatments consisted of the control group (CON), which was a corn-soybean meal diet containing 5% fish meal, and the other four treatments, which replaced a set amount of fish meal with either Prosin (2.5% or 5%) or Protide (2.5% or 5%). The diets were formulated to provide same nutrient levels. The results showed that on a DM basis, both of the DE and ME contents were lower in Prosin and Protide than that of fish meal (p<0.05). The SID of CP and all essential AA were greater in fish meal than in Prosin and Protide (p<0.05). The pigs fed CON diet had greater weight gain and lower feed conversion rate (FCR) than pigs fed 5% Prosin and 5% Protide diets (p<0.05). The digestibility of CP was greater in pigs fed CON, 2.5% Prosin and 2.5% Protide diets than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). Villus height in jejunum and ileum, and villus height to crypt depth ratio in the jejunum were higher (p<0.05) in pigs fed CON, 2.5% Prosin and 2.5% Protide diets compared with the 5% Prosin and 5% Protide diets. Pigs fed CON diet had greater villus height to crypt depth ratio in the ileum than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). In conclusion, although Prosin and Protide contained lower ME content and SID of AA than fish meal, Prosin and Protide replacing 50% of fish meal in diet with identical nutrient levels could obtain similar performance, nutrient digestibility and intestinal morphology in weaned pigs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.1
• /
• pp.43-48
• /
• 2019

This study was conducted to investigate the effect of extruded pellet (EP) size on the growth performance of olive flounder Paralichthys olivaceus at the juvenile (Exp-I; $62.2{\pm}0.05$), growing (Exp-II; $150{\pm}1$) and sub-adult (Exp-III; $299{\pm}1$) stages. In Exp-I (3, 4, 5 and 6 mm diets), Exp-II (4, 9, 11 and 13 mm diets) and Exp-III (9, 11, 13 and 16 mm diets), triplicate groups of fish were fed four EP diets of different pellet sizes. In Exp-I, larger pellet sizes were significantly better than the smallest pellet size (3 mm). In Exp-II, significantly improved feed and protein efficiency were observed with increasing pellet size. The feed conversion ratios of the fish fed the 4 and 9 mm diets were significantly lower than those of fish fed 11 and 13 mm diets. The dietary digestibility of protein and energy was higher in smaller EPs than in larger sizes. In Exp-III, the growth performance of fish was not affected by the pellet size. However, feed intake was significantly affected, increasing with increasing pellet size. Therefore, the optimum pellet sizes for olive flounder under the conditions in this study were 5 mm for 60-150 g fish and 9 mm for 150-500 g fish.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.8
• /
• pp.1148-1156
• /
• 2011

Compensatory growth of juvenile olive flounder Paralichthys olivaceus fed different diets with different feeding regime was compared. Four hundred fifty fish (twenty five fish per tank) were randomly distributed into 18 of 180 L flow-through tanks. Six treatments were prepared: fish were hand-fed with the control (C) diet to satiation twice a day, six days a week, for 8 weeks (C-8W treatment); and other groups of fish were starved for 2 weeks and then fed with the C, high protein (HP), high carbohydrate (HC), high lipid (HL), and combined protein, carbohydrate and lipid (CPCL) diets to satiation twice a day, six days a week, for 6 weeks, referred to as C-6W, HP-6W, HC-6W, HL-6W, and CPCL-6W treatments, respectively. Final body weight of fish in HP-6W treatment was higher than that of fish in C-6W, but not different from that of fish in C-8W, HC-6W, HL-6W and CPCL-6W treatments. Specific growth rate of fish in HP-6W treatment was higher than that of fish in all other treatments except for fish in CPCL-6W treatment. Feeding rate of fish in C-8W treatment was higher than that of fish in HP-6W, HC-6W, HL-6W and CPCL-6W treatments, but not different from that of fish in C-6W treatment. In addition, feeding rate of fish in C-6W treatment was higher than that of fish in HP-6W, HL-6W and CPCL-6W treatments. Feed and protein efficiency ratios of fish in HP-6W, HC-6W, HL-6W and CPCL-6W treatments were higher than those of fish in C-6W treatment. None of moisture, crude protein and ash content of the whole body of fish excluding the liver was different among treatments. Dietary supplementation of protein, carbohydrate, lipid and their combination could improve compensatory growth of fish when fish were fed for 6 weeks after 2-week feed deprivation; especially, supplementation of dietary protein was the most effective to improve compensatory growth of fish.