• Journal of Microbiology and Biotechnology
• /
• v.33 no.10
• /
• pp.1390-1401
• /
• 2023

In this study, a 12-week feeding experiment was conducted to characterize the effects of exogenous α-amylase on the growth, feed utilization, digestibility, plasma α-amylase activity, feed degradation rate, and fecal particle size of olive flounder (Paralichthys olivaceus). Diet was supplemented with 0 (AA₀; control), 100 (AA₁₀₀), 200 (AA₂₀₀), or 400 (AA₄₀₀) mg/kg of α-amylase, respectively. Fish (273.1 ± 2.3 g) were stocked into 12 tanks (25 fish/1,000-L tank) and 3 tanks were randomly selected for each diet group. As a result, α-amylase was found to have no significant effects (p ≥ 0.05) on the growth, feed utilization parameters, and whole-body proximate compositions. α-Amylase-treated fish exhibited only a significant increase in the apparent digestibility coefficient of carbohydrates compared to the controls. In addition, in vitro analyses revealed that α-amylase dose-dependently increased (p < 0.05) the feed degradation rate, while photographs of the intestinal content after 2, 4, and 8 h of feeding demonstrated an improved degradation rate in the α-amylase-treated groups. Plasma α-amylase content was higher in the AA₂₀₀ and AA₄₀₀ groups, whereas the control group produced significantly larger-sized fecal particles (90% size class) than these two groups. In the intestine, no changes were observed in the expression levels of the immune-related TNF-α, IL-1β, IL-2, immunoglobulin-M, HSP-70, lysozyme, and amylase alpha-2A. However, growth-related genes IGF-1, IGF-2, TGF-β3, and growth hormone genes were upregulated in muscle tissues. Collectively, exogenous α-amylase has positive roles in the modulation of the digestibility coefficient, blood α-amylase concentration, growth-related gene expression, and diet degradation for improved digestion in olive flounder.

• 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.48 no.5
• /
• pp.681-687
• /
• 2015

We investigated the effects of feeding rate on the growth performance of growing and sub-adult olive flounder Paralichthys olivaceus, and the optimum feeding rate at high water temperature (25-31℃). In experiment I, two replicated groups of fish (113 g) were fed a commercial diet (CD) at rates of 0, 0.7, 1.2, 1.7, 2.2, and 2.4% (satiation) body weight (BW) per day for 4 weeks. In experiment II, two replicated groups of fish (313 g) were fed a CD feeding rates of 0, 0.3, 0.5, 0.7, 0.9, and 1.0% (satiation) BW per day for 4 weeks. In experiment I, the weight gain (WG) and specific growth rate (SGR) of fish fed at 0.7 and 0.9% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3, 0.5, and 1.0% (satiation) BW per day. In experiment II, the WG and SGR increased significantly as feeding rate increased from 0 to 2.2% BW per day, but decreased in the satiation group (2.4%). Broken-line regression analysis of WG showed that the optimum feeding rate of growing and sub-adult olive flounder were 1.98% and 0.55% BW per day, respectively, at the high water temperature.

• Journal of Aquaculture
• /
• v.11 no.1
• /
• pp.39-48
• /
• 1998

Growth performance and excretions of nitrogen (N) and phosphorus (P) were investigated with carp (Cyprinus carpio) with carp (Cyprinus carpio) grower fed a low pollution diets (A and B) and commercial ones (Com-1 and Com-2). A recirculated rearing system (Exp. I) and a floating net cage system (Exp. II) were employed for two feeding trials in which fish having an initial body weight of 152g and 193g were fed for 41 an 39 days, respectively. The highest weight gain, daily growth rate and protein efficiency ratio were found (P<0.05) in fish fed diet A containing 10% fish meal and 2% monocalcium phosphate (MCP) for both experiments. They also showed the lowest feed conversion ratio and daily feeding ration among treatments. Fish fed diet B containing 10% fish meal, 5% fish protein concentrate and 1% MCP showed weight gain and FCR more improved (P<0.05) than those fed commercial diets. In all groups, whole body cmpositions were not greatly different among treatment, and protein and P contents in final fish ranged from 14.3 to 15.6% and from 0.39 to 0.48%, respectively. Fish fed diet A excreted the least N which were 38.3 in Exp. I and 39.6g/kg gain in Exp. II. However, the values found in fish fed two commercial diets amounted to 59.1 and 58.9g, respectively. A significant decrease in P excretion was also found in fish groups fed diets A and B. In Exp. I, a reduction of 53.4% was shown in fish fed diet A, compared to the averaged value (18.5g P/kg gain) of two commercial groups. In Exp. II conducted using the floating net cages, fish fed diet B excreted the least P (8.6g/kg gain) among the treatment, which was followed by fish fed diet A, showing 48.6% reduction compared to the average value (18.5g/kg gain) for fish fed two commercial diets. The present results clearly showed that N and P excretions from fish culture could be significantly reduced by using the low pollution diet.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.3
• /
• pp.276-283
• /
• 2011

The growth and tolerance for water temperature and salinity were compared among red sea bream Pagrus major (RSB) black sea bream Acanthopagrus schregeli (BSB) and their hybrid ($F_1$), female RSB ${\times}$ male BSB. The growth of the $F_1$ fish did not differ until 27 days after hatching (dAH), after which the most rapid growth was observed until approximately 300 dAH, followed by RSB and BSB. However, the RSB had out grown the $F_1$ fish by approximately 303 dAH. By 480 dAH, the RSB were largest, followed by the $F_1$ and BSB groups. The tolerances for high and low water temperature were significantly different for each species and growth stage. The largest tolerance spectrum was observed in the BSB group, and the tolerance spectrums gradually decreased with increasing final body weight. During the salinity tolerance trials, all of the species started to die following transfer into freshwater (0 psu). BSB showed the highest survival rate when kept in fresh water for an average of 29.9 hours, while the $F_1$ fish were more tolerant than the RSB fish. The fish were increasingly tolerant to fresh water and changes in water temperature as they grew, while the size of the temperature spectrum remained unchanged but shifted to a lower temperature range with growth. Our results demonstrate that $F_1$ performed well in terms of growth compared to parental fish, with higher temperature and salinity tolerances than RSB, and is thus suggested to be a suitable aquaculture species for Korea and northeast China.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.11
• /
• pp.1598-1608
• /
• 2013

An optimum dietary carbohydrate content is important for maximum fish growth. In this study, we fed Wuchang bream (Megalobrama amblycephala) with either control diet (30.42%) or high carbohydrate diet (52.92%) for 90 d. Fish were fed to apparent satiation three times daily in an aquarium with automatic temperature control and circulated water. Growth performance, plasma biochemical parameters, hepatic morphology and enzyme activities were determined. It was shown that compared to fish fed control diet, fish fed high carbohydrate diet had higher plasma triglyceride and cortisol levels for d 90, and lower alkaline phosphatase level for d 45, lower hepatic superoxide dismutase and total antioxidative capacity for d 90, higher malondialdehyde for d 45 and glycogen content for d 45 and 90 (p<0.05). Histological and transmission electron microscopy studies showed that hepatocytes of fish fed high carbohydrate diet contained large lipid droplets, causing displacement of cellular organelles to periphery of hepatocytes. The relative level of hepatic heat shock protein 70 (HSP70) mRNA of Wuchang bream fed high carbohydrate diet was significantly higher than that of fish fed the control diet for 90 d (p<0.05). These changes led to decreased specific growth rate and increased feed conversion ratio (p<0.05). Upon hypoxia challenge, fish fed high carbohydrate diet had higher cumulative mortality than those fed the control diet (p<0.05). These results suggested that high dietary carbohydrate (52.92%) was detrimental to the growth performance and health of Wuchang bream.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.12
• /
• pp.1794-1799
• /
• 2008

This preliminary feeding trial was conducted to study the effects of different dietary selenium (Se) levels on growth performance and toxicity in juvenile black seabream, Acanthopagrus schlegeli (Bleeker). Fish averaging $7.0{\pm}0.1g$ ($mean{\pm}SD$) were fed one of the five semi-purified diets containing 0.21, 0.30, 0.52, 1.29 and 12.3 mg sodium selenite ($Na_2SeO_3$)/kg diet (Se 0.21, Se 0.30, Se 0.52, Se 1.29 or Se 12.3) for 15 weeks. After the feeding trial, weight gain (WG), feed efficiency (FE), specific growth rate (SGR) and protein efficiency ratio (PER) of fish fed Se 0.21, Se 0.30, Se 0.52 and Se 1.29 diets were not significantly different, however fish fed Se 12.3 diet showed significantly lower WG, FE, SGR and PER than those of fish fed the other diets (p<0.05). Fish fed Se 0.21, Se 0.30, Se 0.52, Se 1.29 and Se 12.3 diets showed no significant differences in hematocrit (PCV), hemoglobin (Hb) and red blood cells (RBC), however fish fed Se 12.3 diet showed lower values of PCV, Hb and RBC than those of fish fed the other diets. Histopathological lesions such as tubular necrosis and polycystic dilation of tubules in the kidney tissues were observed in fish fed Se 12.3 diet. Se was accumulated in a dose-dependent manner in the liver, kidney, muscle and gill tissues. Based on the results of this preliminary feeding trial, a dietary Se level of 0.21 mg $Na_2SeO_3/kg$ diet could be optimal for proper growth performances, and a dietary Se level of 12.3 mg $Na_2SeO_3/kg$ diet may ultimately be toxic to juvenile black seabream, Acanthopagrus schlegeli.

• Journal of Aquaculture
• /
• v.12 no.2
• /
• pp.137-143
• /
• 1999

The effects of dietary protein level on growth, feed utlization and liver size were studied with juvenile haddock (Melanogrammus aeglefinus) of 6.88$\pm$0.54 g (mean$\pm$SD). Five isoenergetic diets containing 44.4 to 64.7% protein were fed to triplicate groups of 50 fish in a flow-through system for 6 weeks. All fish showed a relative increase of more than 300% in final weight. There were, however, no significant differences (P>0.05) in weight gain (16.1 to 17.3 g) and specific growth rate (2.9 to 3.0) among fish groups. A higher protein diets resulted in a lower feed intake. Feed: gain ratio linearly improved (P<0.05) when protein level increased from 44.4 to 59.7%. The lowest protein efficiency ratio was observed in fish fed the highest protein diet. Hepatosomatic index of fish significantly decreased from 10.7 to 7.3% with an increase in protein level. Results from this study suggest that haddock could grow well even when fed the diet with protein lower than 44.4%.

• Journal of fish pathology
• /
• v.25 no.2
• /
• pp.103-109
• /
• 2012

The objective of this study was to investigate the effects of exposured $Cu^{2+}$ on growth and bioaccumulation of abalone Haliotis discus hannai. Abalone were exposed to various concentration of $Cu^{2+}$ (0, 5, 10, 20, $40{\mu}g/L$). Bioaccumulation of tissues, hepatopancreas, muscles and gills were measured. hepatopancreas and gills $Cu^{2+}$ concentration of abalone increases to extent during the 4 weeks accumulation time. But muscles showed no significant changes, with respect to control. These data indicate that abalone Haliotis discus hannai hepatopancreas and gills can be considered adequate target tissues for waterborne exposured of $Cu^{2+}$. Weight growth rate of abalone exposed to $Cu^{2+}$ was significantly decreased in 20 and $40{\mu}g/L$ groups compared to control. This study revealed that high $Cu^{2+}$ concentration (${\geq}20{\mu}g/{\ell}$) reduced growth of abalone. These data indicate that excessive waterborne $Cu^{2+}$ can affect the toxicity of xenbiotics to abalone through alterations in growth rate. Thus, environmental standard of $Cu^{2+}$ $20{\mu}g/L$, should be considered a potential source of variation in toxicological studies with abalone.

• Journal of Fisheries and Marine Sciences Education
• /
• v.26 no.2
• /
• pp.444-454
• /
• 2014

The range of optimization problem in aquaculture is very wide, resulting from the range of species, mode of operation. Quite a few studies focus marine net-cages, but studies on land based culture farm are few or no. This paper considers a allocation problem to meet production planning in land based aquaculture system. A water pool allocation model in land based aquaculture system was developed. The solution finds the value of decision variable to minimize yearly production costs that sums up the water pool usage cost and sorting cost. The model inputs were (1) the fish growth rate (2) critical standing corp (3) number of water pool (4) number of fish. The model outputs were (5) number of water pool in growing phase (6) cost of cultivation (6) optimal facility allocation(number of water pool for each growing phase). To solve the problem, an efficient heuristic algorithm based on a greedy manner is developed. Branch and bound and heuristic is evaluated through numerical examples.