• Journal of Aquaculture
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• v.21 no.3
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• pp.190-195
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• 2008

We investigated the changes in growth, digestive enzymes activities, nucleic acids contents and RNA/DNA ratio of flounder Paralichthys olivaceus larvae (C for Paracyclopina nana, A for Artemia, and M for Mix of C and A) for 14 to 28 DAH. Body length of flounder larvae showed the best in the C trial at 28 DAH. The change of nucleic acids contents showed faster in C and M trials than A trial. And RNA/DNA ratio showed the significantly faster changes in C trial than A trial. High metamorphosis rates were also observed in C and M trial. $\alpha$-amylase activities increased gradually up to 28 DAH in all trials. Total alkaline protease (TAP) activities of A trial showed the highest value to 9 mU/larvae at 26 DAH. But others trials showed lower to $5{\sim}6$ mU/larva than A trial. TAP:$\alpha$-amylase activity ratio did not significantly changed to $0.025{\sim}0.053$ in A trial during the experiments. But, C and M trials tended to gradually decrease from $0.078{\sim}0.083$ (initial) to $0.013{\sim}0.018$ (final). Therefore, it shown the ratio gradually decreased of TAP:$\alpha$-amylase activity, stability of TAP activity, and rapid change of nucleic acids in trials grown positively. Thus, because P. nana could continuously supply the optimal nutrients for flounder larvae, we suggested the supplement of the copepod to an efficient feed of the flounder larvae.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.582-589
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• 2008

This study attempted to determine effects of recombinant porcine epidermal growth factor (pEGF) and glutamine (Gln) supplement on the growth performance and intestinal development of piglets weaned at 14 days of age. A total of ninety-six piglets were allotted to one of four dietary treatments which comprised inclusion of 1.0 mg pEGF supernatant/kg diet or 0.5% Gln both alone and in combination. Each treatment consisted of four replicates with six pigs per pen for a 28 days experimental period. Two pigs per replicate were sacrificed and gastrointestinal tract samples were collected on day 14. Data showed that dietary treatment failed to promote growth performance. On day 14, diets supplemented with pEGF elevated pancreatic chymotrypsin, jejunal alkaline phosphatase, sucrase, lactase and maltase activities (p<0.05), but failed to alter the small intestinal villus morphology, DNA, or protein content of gastrointestinal mucosa. Diets supplemented with Gln increased pancreatic chymotrypsin activity, tended to enhance the protein contents of gastric (p = 0.08) and jejunal mucosa (p = 0.09) but did not influence the serum IgA level or the enzyme activity in the gastrointestinal tract. On day 28, the diets supplemented with Gln increasedt (p<0.05) serum IgA and the proliferation of peripheral blood mononuclear cells by PHA stimulation. However, a combination of pEGF and Gln did not have a synergistic effect on these biomarkers in early-weaned piglets. The results demonstrate that diets supplemented with recombinant pEGF supernatant indeed improve intestinal digestive enzyme activity and diets supplemented with Gln increases the immune response in early-weaned piglets.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.84-92
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• 1999

The rumen microbial ecosystem is coming to be recognized as a rich alternative source of genes for industrially useful enzymes. Recent advances in biotechnology are enabling development of novel strategies for effective delivery and enhancement of these gene products. One particularly promising avenue for industrial application of rumen enzymes is as feed supplements for nonruminant and ruminant animal diets. Increasing competition in the livestock industry has forced producers to cut costs by adopting new technologies aimed at increasing production efficiency. Cellulases, xylanases, ${\beta}$-glucanases, pectinases, and phytases have been shown to increase the efficiency of feedstuff utilization (e.g., degradation of cellulose, xylan and ${\beta}$-glucan) and to decrease pollutants (e.g., phytic acid). These enzymes enhance the availability of feed components to the animal and eliminate some of their naturally occurring antinutritional effects. In the past, the cost and inconvenience of enzyme production and delivery has hampered widespread application of this promising technology. Over the last decade, however, advances in recombinant DNA technology have significantly improved microbial production systems. Novel strategies for delivery and enhancement of genes and gene products from the rumen include expression of seed proteins, oleosin proteins in canola and transgenic animals secreting digestive enzymes from the pancreas. Thus, the biotechnological framework is in place to achieve substantial improvements in animal production through enzyme supplementation. On the other hand, the rumen ecosystem provides ongoing enrichment and natural selection of microbes adapted to specific conditions, and represents a virtually untapped resource of novel products such as enzymes, detoxificants and antibiotics.

• Biomedical Science Letters
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• v.11 no.4
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• pp.517-523
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• 2005

The purpose of this study was to determine the effect of rat intestinal a-glucosidase inhibitor; methanol $(80\%)$, ethanol $(80\%)$ and water extract of Schizandra chinensis in Korea (KS: Schizandra chinensis in Korea) and China (CS: Schizandra chinensis in China). When the final concentration was 1 mg/ml for each sample (KS and CS), methanol extract of KS ($IC_{50}$ 1.62 mg/ml) showed $46.8\%$, ethanol extract of KS ($IC_{50}$ 1.48 mg/ml) showed $47.4\%$, water extract of KS ($IC_{50}$ 1.72 mg/ml) showed $46.3\%$ and methanol extract of CS ($IC_{50}$ 8.35 mg/ml) showed $13.3\%$, ethanol extract of CS ($IC_{50}$ 8.05 mg/lml) showed $16\%$, water extract of CS ($IC_{50}$ 8.37 mg/ml) showed $11.54\%$ of inhibitor for p-nitrophenyl $\alpha-D-glucopyranoside$ (pNPG) $\alpha-glcosidase$ activity, respectively. And the contents of total phenol, flavonoid of Schizandra chinensis were measured. When the final concentration was 1mg/ml for each sample (KS and CS), total phenol and flavonoid in KS were higher than CS, respectively. The order superoxide dismutase (SOD) activity $IC_{50}$ values of each solvent extracts of KS were: 2.006 mg/ml methanol extract, 2.304 mg/ml ethanol extract and 2.5 mg/ml water extract, which were higher than that of each solvent extracts CS as: 2.881 mg/ml methanol extract, 3.085 mg/ml ethanol extract and 3.190 mg/ml water extract.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.109-114
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• 2008

To evaluate the extent of Sea-Nine 211 (4,5-dichloro-2-n-octyl-3(2H) isothiazolone), one of the alternating organic booster compound used in antifouling paint to replace TBT, on marine benthic bivalve, we injected Sea-Nine 211 to clam, Pseudocardium sachalinensis, and then determined some xenobiotics metabolizing enzyme activities, especially EROD (ethoxyresorufin deethylase) and MROD (methoxyresorufin demethylase), in digestive gland during 4 day-exposure period. Moreover, the results were compared with those of TBT exposed clam. CYP1A1 dependant EROD activity in both the Sea-Nine 211 and the TBTC exposure groups showed no significant differences compared to those of the solvent control group. CYP1A2 dependant MROD activity in Sea-Nine 211 exposure group was significantly induced, but no significant difference was obtained in the TBTC exposure group. These results indicate that Sea-Nine 211 demonstrated a tendency to induce MROD activity, while TBTC inhibits the activities of this enzyme.

• Ocean and Polar Research
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• v.44 no.4
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• pp.319-329
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• 2022

The paramyxean parasite Marteilioides chungmuensis infects the cytoplasm of the eggs of Pacific oysters Crassostrea gigas , resulting in spawning failure of the infected females. Such infected eggs appear as bump-like nodules on the body in late fall when most of the uninfected females complete spawning. In this study, we estimated the quantity of the infected eggs using an enzyme-linked immunosorbent assay (ELISA), which is destroyed by M. chungmuensis parasitism. In December, the infected oysters collected from Tongyoung on the south coast exhibited numerous yellowish bump-like nodules as signs of infection. In histology, the infected oysters exhibited mature eggs in the follicle, which were heavily infiltrated by hemocytes. ELISA indicated that the infected egg mass accounted for 7.52±5.50 percent of the body weight, suggesting the ovarian parasite causes substantial reproductive loss. Histology also indicated that the infected oysters are in a poor nutritional condition, as the digestive gland atrophy (DGA) level is comparatively higher than the uninfected oyster. The total carbohydrate contents in the infected oysters (108.68±44.41 mg/g dry wt) were significantly lower than in uninfected oysters (269.76±50.97 mg/g dry wt), suggesting that M. chungmuensis parasitism also affected the energy storage capacity of the host during the resting stage.

• Food Science of Animal Resources
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• v.44 no.3
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• pp.533-550
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• 2024

Peptides with bioactive effects are being researched for various purposes. However, there is a lack of overall research on pork-derived peptides. In this study, we reviewed the process of obtaining bioactive peptides, available analytical methods, and the study of bioactive peptides derived from pork. Pepsin and trypsin, two representative protein digestive enzymes in the body, are hydrolyzed by other cofactors to produce peptides. Bicinchoninic acid assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, chromatography, and in vitro digestion simulation systems are utilized to analyze bioactive peptides for protein digestibility and molecular weight distribution. Pork-derived peptides mainly exhibit antioxidant and antihypertensive activities. The antioxidant activity of bioactive peptides increases the accessibility of amino acid residues by disrupting the three-dimensional structure of proteins, affecting free radical scavenging, reactive oxygen species inactivation, and metal ion chelating. In addition, the antihypertensive activity decreases angiotensin II production by inhibiting angiotensin converting enzyme and suppresses blood pressure by blocking the AT1 receptor. Pork-derived bioactive peptides, primarily obtained using papain and pepsin, exhibit significant antioxidant and antihypertensive activities, with most having low molecular weights below 1 kDa. This study may aid in the future development of bioactive peptides and serve as a valuable reference for pork-derived peptides.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.875-881
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• 1998

To develop functional food material with angiotensin converting enzyme (ACE) inhibitory peptides, muscle protein of anchovy, Engraulis japonica was hydrolyzed during 48 hrs by digestive pretenses such as pepsin, trypsin, $\alpha$-chymotrypsin, and commercial proteases such as papain, bromelain, complex enzyme, Elavourzyme, Novozym, Neutrase, Protamex and Alcalase. The only $50\%$ ethanol soluble hydrolysates were tested for inhibitory activity against ACE and yield of $50\%$ ethanol soluble peptide-nitrogen ($ESPN_{50}$). ACE inhibition effects and yield of $ESPN_{50}$ occurred as hydrolysis time increased to 8 hrs, Among those pretenses tested, hydrolysates by Alcalase and $\alpha$-chymohypsin had greater ACE inhibitory activity (80 and $74\%$, reipectively) with eletated levels of $ESPN_{50}$ (48 and 58 mg/ml, respectively), while Protamex hydrolysates had greater ACE inhibitory activities ($73\%$) with reduced levels of $ESPN_{50}$ (7.2mg/ml) than others. Amino acid compositions of $50\%$ ethanol solubles obtained from those hydrolysates were rich in glutamic acid, aspartic acid, cysteine and leucine.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.2
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• pp.67-73
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• 2013

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity ($+18{\pm}1.8%$ and higher egg hatching rate ($+10.96{\pm}1.3%$) was recorded in the F1hybrid ($L{\times}D$). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria ${\times}$ Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.

• Journal of Aquaculture
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• v.1 no.1
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• pp.103-108
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• 1988

Protoplasts were isolated enzymatically from thalli of Porphyra tenera in relation to its utilization in breeding. As the concentration of the enzymes and incubation period increased, so did the yield of protoplasts. When a 250 mg fresh weight of the thalli was incubated in the $12\%$ abalone digestive enzyme mixture at $22^{\circ}C$ for 3 hours, about $2.5\times10^6$ protoplasts were released. The size of protoplasts ranged between 9$\mu$m and 25$\mu$m, with an average of 14.5$\mu$m.