• Journal of Aquaculture
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• v.19 no.1
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• pp.1-6
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• 2006

The tryptic enzyme activities from hepatopancreas, foregut, midgut and feces were examined to optimize the feeding method in whiteleg shrimp, Litopenaeus vannamei. The highest tryptic enzyme activity was found in hepatopancreas. The enzyme activities of hepatopancreas were 4 times higher than those of foregut per mg dry weight at 30 minutes feeding. Post feeding period, the activities of hepatopancreas increased continuously up to 30 hours after feeding. Trypsin activities of foregut showed about 3 times higher than did those of midgut. Average activity of foregut reached the pick with $303{\pm}68\;(mean{\pm}SE)$ nmol/mg/min at two hours after feeding and kept the activity up to 4 hours after feeding and thereafter the activity decreased. Average tryptic enzyme activity of midgut increased to $96{\pm}26nmol/mg/min$ up to two hours after feeding and it decreased to $52{\pm}17nmol/mg/min$ at five hours after feeding eventhough the gastric evacuation rate was still 50% by then. Foregut clearance occurred in 30 minutes after feeding and midgut weight increased up to 2 hours after feeding. Also we found that the maximal food ingestion in foregut was equivalent to the average 0.3% of its body weight by 30 minutes after feeding. Up to 5 hours after feeding, the weight ratio of midgut to body weight reduced, but still the weight ratio of foregut to body weight kept the similarity until then. These indicated that the tryptic enzyme activity and the clearance rate are different among the digestive organs and between forgot and midgut during the post feeding period in whiteleg shrimp.

• ALGAE
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• v.29 no.3
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• pp.227-235
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• 2014

The red seaweed, Gracilaria tikvahiae McLachlan, was cultivated in open water farms in urbanized estuaries of Long Island Sound (26-30 psu of salinity) and New York City (20-25 psu), USA in 2011. Plants were harvested monthly from summer (August, $24^{\circ}C$) to fall (November, $13^{\circ}C$) and analyzed for total nitrogen, protein, and amino acid content. On a dry matter (DM) basis, nitrogen and protein significantly increased over the harvest period until October and then plateaued. Nitrogen increased from $22{\pm}1g\;kg^{-1}$ DM in August to $39{\pm}3g\;kg^{-1}$ DM in October (p < 0.001). Protein increased from $107{\pm}13g\;kg^{-1}$ DM in August to $196{\pm}5g\;kg^{-1}$ DM in November (p < 0.001). With two exceptions, amino acid concentrations expressed on a crude protein (CP) basis were similar over the harvest period. Essential amino acids accounted for $48{\pm}1%$ of all amino acids present with lysine and methionine averaging $56{\pm}2g\;kg^{-1}$ CP and $18{\pm}1g\;kg^{-1}$ CP, respectively. Histidine was underrepresented among essential amino acids and averaged $13{\pm}1g\;kg^{-1}$ CP. Taurine ranged from 2.1 to $3.2g\;kg^{-1}$ DM. With its moderate levels of lysine, methionine and taurine, ocean farmed G. tikvahiae has the potential of overcoming many nutrient deficiencies currently associated with terrestrial plant ingredients in alternative feeds for fish and shrimp.

• Journal of Aquaculture
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• v.21 no.4
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• pp.309-316
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• 2008

Effects of the various dietary additives on growth and tolerance of abalone Haliotis discus hannai to the stresses were determined in the 16-week feeding trial. Seventy juvenile (an initial body weight of 4.2 g) abalone per container were randomly distributed into 21, 50 L plastic rectangular containers each. The six kinds of experimental diets were prepared: control (CON) with no additive, by-product of green tea (BPG), extract of figs (EF), extract of green tea (EG), commercially available product of Hearok (PH), and Haematococcus (HC). In addition, dry sea tangle (ST) was prepared to compare the efficiency of the experimental diets. Fishmeal, soybean meal and shrimp head meal were used as the protein source, and dextrin, sea tangle powder and wheat flour, and soybean oil and fish oil were used as the carbohydrate and lipid sources, respectively in the experimental diets. The experimental diets were fed to abalone once a day at a satiation level with a little leftover. The feeding trial lasted for 16 weeks. At the end of the 16-week feeding trial, abalone was exposed to the different types of stresses (air exposure, and sudden changes of rearing temperature and salinity). Survival of abalone fed the sea tangle was highest. However, weight gain of abalone fed the EF, EG and PH diets was significantly (P<0.05) higher than that of abalone fed the BPG diet or dry sea tangle. Shell length of abalone fed the all experimental diets was significantly (P<0.05) higher than that of abalone fed the dry sea tangle. Accumulated mortality of abalone fed the sea tangle was low when exposed to the different types of stresses. Also, relatively low mortality was achieved in abalone fed the HC and EF diets. In considering these results, it can be concluded that the various sources of additives is effective to improve production of abalone, and Haematococcus and extract of figs can be considered as dietary additives to improve resistance of abalone against the different types of stresses.

• Journal of Aquaculture
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• v.19 no.4
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• pp.275-280
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• 2006

Effect of the various sources of dietary additives on growth, body composition and shell color of abalone Haliotis discus hannai was investigated for 16 weeks. Forty juvenile abalone averaging 13.5 g were randomly stocked into 21 of 50 L plastic rectangular containers each. Eight kinds of additives were prepared for this study: four commercially available microalgae [Haeatococcus (Hae), Isochrysis galbana (Iso), Shizochytrium (Sch) and Spirulina (Spi)], three crustacean meals [krill meal (KM), shrimp head meal (Shm) and red crab meal (Rcm)], and green tea by-product (Gre). In addition, dry sea tangle (Dst), Laminaria japonica, as a control, was prepared. Casein, dextrin and a mixture corn oil and fish oil was protein, carbohydrate and lipid sources, respectively, in the experimental diets. The 2% each additive was included into the experimental diets. The experimental diets were fed to abalone once a day at the ratio of $1.5{\sim}2.0%$ total biomass of abalone with a little leftover throughout the 16-week feeding trial. Survival of abalone was not significantly (P>0.05) affected by the experimental diets. However, weight gain of abalone fed the all experimental diets containing the various sources of additives was significantly (P<0.05) higher than that of abalone fed the Dst diet. Weight gain of abalone fed the Spi diet was highest and Shi, KM and Iso diets in order. Shell length and the ratio of soft body weight to body weight of abalone was not significantly (P>0.05) affected by the experimental diets. However, shell width of abalone fed the all experimental diets containing the various sources of additives was significantly (P<0.05) higher than that of abalone fed the Dst diet. The shell color of abalone fed the Spi diet was improved the most distinctively and similar to that of natural abalone. Therefore, it can be concluded that the experimental diets with the various sources of additives (microalgae and crustacean meals) was effective to improve growth of abalone and dietary inclusion of Spirulina was most effective to improve shell color of abalone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.371-382
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• 1992

Biochemical composition, the rates of nitrogen excretion in the form of ammonia, amino acids and total nitrogen, and oxygen consumption of the shrimp Crangon affinis were measured at three temperature regimes $(7,\;15,\;and\;25^{\circ}C)$ and the variations were also determined for starvation periods (1-25 days). The composition of the major biochemical fractions was analysed into carbohydrate: $4.2\%,\;protein:\;68.6\%,\;lipid:\;7.0\%,\;chitin:\;6.3\%,\;and\;ash:\;14.6\%,$ all expressed as percentage of dry weight. Molting frequency was lower at $7^{\circ}C\;than\;25^{\circ}C$ during the period of starvation, and during the same period the higher temperature was, body weight and body compositions the more decreased. Through all starvation periods $O_2$ consumption tended to decrease but total nitrogen tended to increase at any temperature regimes. The dominant form of excreted total nitrogen was ammonia-N at any temperature. From the O:N ratio it appeared that carbohydrate and lipid reserves were quickly exhausted (1-5 days), and that proteins were the substrates oxidized to meet the energetic requirements of C. affinis at any temperature. After 25 days of starvation the O:N ratio remained constant near a value of 8, which indicates that only proteins were being utilized at three temperatures. After 25 days of starvaion C. affinis excreted 23.01ug N/mg body nitrogen per day at $7^{\circ}C,\;32.97\mu g\;N/mg$ body nitrogen per day at $15^{\circ}C,\;and\;44.81\mu g\;N/mg$ body nitrogen per day at $25^{\circ}C$, and lost about 1.75, 2.47 and $3.29^{\circ}C$ of body protein per day at 7, 15, and $25^{\circ}C$ respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.380-389
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• 1994

Larvae of the freshwater shrimp, Macrobrachium nipponense(De Haan) were reared in the laboratory under constant conditions ($25^{\circ}C,\;7\%0$ S), and their feeding rate, oxygen consumption, ammonia nitrogen excretion, and growth were measured at regular intervals during development from hatching to post larval stage. Growth was measured as dry weight, carbon, nitrogen, hydrogen, protein and lipid. All these physiological and biochemical traits revealed significant changes from instar to instar. Average feeding rate was high in intermolt stage of the molt cycle and it showed a bell-shaped pattern. Respiration(R) increased from hatching to post larval stage. Excretion(U) increased in intermolt phase of larvae and it showed a bell-shaped variation pattern, in all larval instars with a maximum near the middle of the molt cycle. Regression equations describing rates of feeding, growth, respiration and ammonia excretion as functions of time during individual larval molt cycles were inserted in a simulation model, in order to analyse time-dependent patterns of variation as well as in bioenergetic efficiencies. Carbon was initially increased and nitrogen showed a tendency to increase in premolt phase during individual molt cycles. Protein remained clearly the predominant biochemical constituent in larval biomass.

• Journal of Aquaculture
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• v.21 no.3
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• pp.184-189
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• 2008

Tryptic enzyme activities in the digestive glands (hepatopancreas) and digestive tracts of Pacific white shrimps Litopenaeus vannamei were assayed at three water temperature regimes. At $26^{\circ}C$, trypsin activity in the hepatopancreas was 200% higher than at $23^{\circ}C$ and 300% higher than at $20^{\circ}C$. The highest foregut trypsin activity levels showed no significant difference in the temperature regimes, but the time between peaks in foreguts and midguts shortened at higher temperature. In the midgut, the level of enzyme activity was highest at $26^{\circ}C$ regardless of the amount of ingested feed. The ratio of foregut and/or midgut dry weight to the body wet weight indicated feed movement through the digestive track directly and gave accurate account about the feeding mechanism. Maximum feed ingestion in the foregut was equivalent to 0.6% of the body weight (wet weight) at $23^{\circ}C$, 0.4% of the body weight at $20^{\circ}C$, and 0.5% of the body weight at $26^{\circ}C$. In view of the temperatures chosen for this study, although maximum ingestion was observed at $23^{\circ}C$, the shrimps showed highest enzyme activity, but lowest feed retention time at $26^{\circ}C$ and lowest enzyme activity, but highest retention time at $20^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1063-1067
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• 1997

This study was performed to assess the levels of the trace elements(Fe, Cu, Zn, Cr, Co, Mn, Pb, and Cd) in salt-fermented fish products from some areas of the west coast in Korea. Seven samples were Shrimp(Seawoo-jeot), Clam(Jogai-jeot), Oyster(Orikul-jeot), big eyed horring(Bendeng-ie jeot), Mysis(Gonjeng-ie jeot), Hwangandali(Hwangsegi-jeot), and Squid, Han Chi(Han chi-jeot). They were ashed with ternary solution. After ashing the samples, the amount of trace elements in the samples were measured by ICP. The moisture content of the 7 samples before freezing dry were 68.36, 71.52, 81.19, 62.27, 71.30, 64.27, and 66.74%, respectively. Jogai-jeot and Gonjeng-ie jeot contained the most amount of moisture among the samples. Fe contents were 66.46, 309.10, 27.03, 23.01, 132.45, 35.75, and 9.72ppm, respectively. Jogai-jeot contained the most amount of Fe among the samples. Cu contents were 4.60, 4.36, 3.75, 2.21, 10.36, 2.71, and 58.15ppm, respectively. Hanchi-jeot contained the most amount of Cu among the samples. Zn contents were 16.02, 75.06, 37.43, 28.43, 132.45, 35.75, and 9.72ppm, respectively. Gonjeng-ie jeot contained the most amount of Zn among the samples. Cr contents were 0.80, 1.61, 0.84, 0.96, 1.12, 0.96, and 0.59ppm, respectively. Jogai-jeot contained the most amount of Cr among the samples. Co contents were 0.13, 0.54, 0.31, 0.46, 0.50, 0.63, and 0.35ppm, respectively. Hwangsegi-jeot contained the most amount of Co among the samples. Mn contents were 7.30, 10.69, 14.87, 4.12, 8.03, 2.94 and 1.54ppm, respectively. Origkul-jeot contained the most amount of Mn among the samples. Pb contents were 1.80, 4.30, 2.53, 4.61, 3.08, 5.04, and 2.74ppm, respectively. Hwangsegi-jeot contained the most amount of Pb among the samples. Cd contents were 0.005, 0.03, 0.06, 0.005, 0.01, 0.00, and 0.10ppm, respectively. Hanchi-jeot contained the most amount of Cd among the samples. This study is limited within 7 samples caught and producted from the some areas of the west coast in Korea. Therefore, I hope there will be broader experiments concerned with this study to make clear not only nutritional aspect(the contents of Fe, Cu, Zn, Cr, Co, and Mn) but also toxicological aspect(the contents of Pb and Cd).