• Korean Journal of Agricultural Science
• /
• v.48 no.2
• /
• pp.333-342
• /
• 2021

This study attempted to compare total digestible nutrients (TDN) calculated as Rohweder, NRC, and Waldo and Peiqiang methods and TDN measured as digestibility of in vivo appearance. Rohweder method showed that the TDN of rice straw and timothy were 54.32% and 57.79%, respectively. In NRC method, the digestibility of neutral detergent fiber (NDF) and TDN of rice straw were 50.76% and 53.15%, respectively. When NRC method was applied in Timothy, the digestibility of NDF and TDN were 51.53% and 55.22%, respectively. Waldo and Peiqiang method calculated the results through the rumen in situ test. NDF digestibility of rice straw and timothy was 44.61% and 51.82%, which was different from the results of NRC method. In addition, TDN was predicted to be 48.85% for rice straw and 55.41% for timothy. In the in vivo apparent digestibility experiment, the digestibility of NDF and TDN in rice straw was 41.10% and 44.79%, respectively. In timothy, the digestibility of NDF and TDN were measured as 51.29% and 58.18%, respectively. As a result of a series of studies, rice straw was found in Rohweder and NRC methods showed higher TDN than other methods. In this study, there was a difference in rice straw by measurement method, but there was no difference in timothy. Therefore, when evaluating the value of feed in order to provide roughage to ruminant, calculation methods must be modified and supplemented. In addition, TDN should be considered to apply several evaluation methods instead of one method.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.6
• /
• pp.1330-1336
• /
• 2005

Polyhydroxyalkanoic acid (PHA) inclusion bodies were analyzed in situ by $^{13}C$-nuclear magnetic resonance ($^{13}C$-NMR) spectroscopy. The PHA inclusion bodies studied were composed of poly(3-hydroxybutyrate) or poly(3hydroxybutyrate-co-4-hydroxybutyrate), which was accumulated in Hydrogenophaga pseudoflava, and medium-chain-length PHA (MCL-PHA), which was accumulated in Pseudomonas fluorescens BM07 from octanoic acid or 11-phenoxyundecanoic acid (11-POU). The quantification of the $^{13}C$-NMR signals was conducted against a standard compound, sodium 2,2-dimethyl-2-silapentane-5-sulfonate (DSS). The chemical shift values for the in vivo NMR spectral peaks agreed well with those for the corresponding purified PHA polymers. The intracellular degradation of the PHA inclusions by intracellular PHA depolymerase(s) was monitored by in vivo NMR spectroscopy and analyzed in terms of first-order reaction kinetics. The H. pseudoflava cells were washed for the degradation experiment, transferred to a degradation medium without a carbon source, but containing 1.0 g/l ammonium sulfate, and cultivated at $35^{\circ}C$ for 72 h. The in vivo NMR spectra were obtained at $70^{\circ}C$ for the short-chain-length PHA cells whereas the spectra for the aliphatic and aromatic MCL-PHA cells were obtained at $50^{\circ}C\;and\;80^{\circ}C$, respectively. For the H. pseudoflava cells, the in vivo NMR kinetics analysis of the PHA degradation resulted in a first-order degradation rate constant of 0.075/h ($r^{2}$=0.94) for the initial 24 h of degradation, which was close to the 0.050/h determined when using a gas chromatographic analysis of chloroform extracts of sulfuric acid/methanol reaction mixtures of dried whole cells. Accordingly, it is suggested that in vivo $^{13}C$-NMR spectroscopy is an important tool for studying intracellular PHA degradation in terms of kinetics.

• Journal of Animal Science and Technology
• /
• v.55 no.2
• /
• pp.123-130
• /
• 2013

Whole cotton seed (WCS) has become one of the major feed ingredients in TMR for dairy cattle in Korea, and WCS for feed use is mostly imported from abroad. Since this genetically modified oil seed is usually fed to the animal in raw state, its germination ability, if last long, often causes concerns about ecological disturbances. In the process of looking for effective conditions to remove germination ability of WCS this study had the objectives to evaluate the nutritional effects of gamma irradiation at doses of 8, 10 and 12 kGy on changes in nutrient contents, anti-nutritional factors, in vitro digestibility and ruminal degradability. No significant differences were found in proximate analysis of nutrients between raw WCS and gamma irradiated one. Glycine and threonine contents significantly increased when the WCS was exposed to gamma ray as compared to untreated WCS (p<0.05). As for fatty acid composition, no significant differences were observed with the irradiation treatment. Free gossypol in WCS was decreased (p<0.05) by gamma irradiation treatment. Of the 3 different levels of gamma irradiation, a dose of 12 kGy was found to be the most effective in reducing free gossypol concentration. Results obtained from in situ experiment indicated that gamma irradiation at a dose of 10 kGy significantly (p<0.05) lowered rumen degradability of both dry matter and crude protein as compared with raw WCS. However, there were no significant differences in rapidly degradable and potentially degradable fractions of crude protein due to 10 kGy gamma irradiation. Overall, this study show that gamma irradiation at a dose of 10 kGy is the optimum condition for removing germination ability of WCS, and could improve nutritive value for the ruminant with respect to the decrease in both ruminal protein degradability and gossypol content of WCS.

• Environmental Engineering Research
• /
• v.10 no.4
• /
• pp.181-190
• /
• 2005

Severe loss or hydrogen occurred in most anaerobic hydrogen fermentation reactors. Several selected methods were applied to suppress the consumption of hydrogen and increase the potential of production. As the first trial, pH shock was applied. The pH of reactor was dropped nearly to 3.0 by stopping alkalinity supply and on]y feeding glucose (5 g/L-d). As the pH was increase to $4.8{\pm}0.2,$ the degradation pathway was derived to solventogenesis resulting in disappearance of hydrogen in the headspace. In the aspect of bacterial community, methanogens weren't detected after 22 and 35 day, respectively. Even though, however, there was no methanogenic bacterium detected with fluorescence in-situ hybridization (FISH) method, hydrogen loss still occurred in the reactor showing a continuous increase of acetate when the pH was increased to $5.5{\pm}0.2$. This result was suggesting the possibility of the survival of spore fanning acetogenic bacteria enduring the severely acidic pH. As an alternative and additive method, nitrate was added in a batch experiment. It resulted in the increase of maximum hydrogen fraction from 29 (blank) to 61 % $(500\;mg\;NO_3/L)$. However, unfortunately, the loss of hydrogen occurred right after the depletion of nitrate by denitrification. In order to prevent the loss entangled with acetate formation, $CO_2$ scavenging in the headspace was applied to the hydrogen fermentation with heat-treated sludge since it was the primer of acetogenesis. As the $CO_2$ scavenging was applied, the maximum fraction of hydrogen was enhanced from 68 % to 87 %. And the loss of hydrogen could be protected effectively.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.2
• /
• pp.323-327
• /
• 1992

An experiment was conducted to determine whether there were any apparent differences in the microbial population, colonization pattern and digestion of guinea grass in situ, between cattle and swamp buffalo. Percentage losses in dry matter (DM), nitrogen (N) and neutral detergent fibre (NDF) of guinea grass were significantly (p<0.01) higher when incubated in the rumen of buffalo than in cattle. Buffalo also showed significantly (p<0.05) faster degradation rates than cattle for each grass component (DM, N, DNF). Light microscopy and SEM examination of the incubated grass materials showed that there were no apparent differences in the pattern of bacterial and fungal invasion and colonization of the grass materials between cattle and buffalo. Attachment of bacteria and fungal zoospores on the grass fragments occurred at 15 min after rumen incubation. After 3 h of rumen incubation, dense population of bacteria was observed in the thin-walled mesophyll and parenchyma tissues, whereas root-like fungal rhizoids were observed in both thin-walled and thick-walled cells. By 6 h, eroded zones were apparent in the thin-walled tissues and in thick-walled tissues with profuse rhizoids. After 24. 48 and 72 h of rumen incubation, most thin-walled tissues were degraded leaving mostly the thick-walled tissues. The predominant bacteria were the curved rods resembling Butyrivibrio sp., the thick rods resembling Fibrobacter sp., the diplococcoids resumbling Ruminococcus sp. And spirochetes. Fungi were predominantly those with spherical or oval sporangia. Fusiform sporangia with acuminate apices which resembled Ruminomyces sp. Were of lesser occurrence. Few protozoa were found on the grass fragments at all incubation times.

• Journal of Aquaculture
• /
• v.1 no.1
• /
• pp.75-84
• /
• 1988

For studying growth of sea squirt, Halocynthia roretzi, from laboratoy grown seeds, in situ culture experiment was carried out off Hansando located in the southern part of Korea from February 1984 to July 1986. In the growth of the mean body height, sea squirt grew up to 9.15 cm during the above period after they were seeded at about 0.05 cm. The meat weight of 1.27 g at the beginning increased to 41.69 g from February 1985 to March 1986. The decreasing tendency in body height, body breadth, total weight and meat weight of sea squirt was observed during the summer season in 1985 when the water temperature reached $23.53^{\circ}C$ the maximum value in monthly mean, and the specific gravity of sea water remained at the lowest level of 1.0233 in monthly mean. Sea squirt became gradually elongated with the decreasing tendency in the relative growth ratio of body breadth to body height with aging. The monthly mortality of sea squirt was especially higher in June and July than in the other months, and the average monthly mortality was $10.83\%$.

• Ocean and Polar Research
• /
• v.32 no.2
• /
• pp.165-175
• /
• 2010

Dietary lipid biomarkers (fatty acids, fatty alcohols, and sterols) in adult specimens were analyzed to compare and understand the feeding ecology of the euphausiid, Euphausia pacifica, from three geographically and environmentally diverse Korean waters (Yellow Sea, East China Sea, and East Sea). Total lipid content of E. pacifica from Korean waters was about 10% dry weight (DW) with a dominance of phospholipids (>46.9% of total lipid content), which are known as membrane components. A saturated fatty acid, C16:0, a monounsaturated fatty acid, C18:1(n-9), and two polyunsaturated fatty acids, C20:5(n-3) and 22:6(n-3), were most abundant (>60% of total fatty acids) in the fatty acid composition. Some of the fatty acids showed slight differences among regions although no significant compositional changes of fatty acids were detected between these regions. Phytol, originating from the side chain of chlorophyll and indicative of active feeding on phytoplankton, was detected all samples. Trace amounts of various fatty alcohols were also detected in E. pacifica. Specifically, krill from the Yellow Sea showed relatively high amounts of longchain monounsaturated fatty alcohols (i.e. 20:1 and 22:1), generally found in herbivorous copepods. Three different kinds of sterols were detected in E. pacifica. The most dominant of these sterols was cholest-5-en-$3{\beta}$-ol (cholesterol). The lipid compositions and ratios of fatty acid trophic markers are indicative of herbivory in E. pacifica from the Yellow Sea and East Sea (mainly feeding on dinoflagellates and diatoms, respectively). The lipid compositions and ratios of fatty acid trophic markers are indicative of carnivory or omnivory in E. pacifica from the East China Sea, mainly feeding on microzooplankton such as protozoa. In conclusion, lipid biomarkers provide useful information about krill feeding type. However, further analyses and experiments (i.e. gut content analysis, in situ grazing experiment, etc.) are needed to better understand the feeding ecology of E. pacifica in various marine environments.

• Ocean and Polar Research
• /
• v.26 no.4
• /
• pp.635-646
• /
• 2004

Chronic outbreaks of green tide in the Nakdong estuary toll a heavy socioeconomic cost. The paper investigates the influence of sediments on the nitrogen eutrophication, being claimed as the primary cause of green tide. To measure the flux of nitrate at the sediments-water interface, sediment cores were taken in Jan., Mar., May and Sep., 2000 at Noksan located in the West-Nakdong river estuary. The dissolved oxygen was profiled and then the pore water was extracted in situ. Core samples were analyzed for their textural characteristics. Cores were incubated by a novel technique to measure the fluxes of nitrate $(NO_3^-)$ and ammonia $(NH_4^+)$ at the sediment-water interface. The dissolved oxygen was depleted usually within several millimeters in the top sediments. Nitrate started to decrease drastically at the layer where dissolved oxygen was nearly depleted. Nitrate was also exhausted within several centimeters, followed by ammonia build up rapidly. The flux at the sediments-water interface calculated from the pore water concentrations revealed that nitrate was removed from the water column into the sediments. The sediment incubation experiment confirmed the above result. On the other hand ammonia were released from the sediment to the water column. As the incubation went on, however, the nitrate concentration in the overlying water was dropped below that of a top sediment. Then the flux is reversed, i.e., nitrate was released from the sediments to the water column. The implication is that the sediment can supply nitrate to the water column if it falls below a certain level. Thus it is likely that sediments in the eutrophicated river buffers the nitrate concentration in the water column, which leads to a prolonged green tide.

• Journal of the Korean GEO-environmental Society
• /
• v.19 no.10
• /
• pp.27-34
• /
• 2018

The effect of cutting-off the leakage was identified by the cement based wall mass constructed in underground, as complete facilities for reinforcement in shear strength of landfill which was subjected to circular failure and for cutting-off the leachate from the costal waste landfill. By (1) visual inspection after underground excavating and (2) compressive strength test for core of underground wall, it could be identified that quality of wall mass constructed in underground was so effective, and by additional test, so as (3) in-situ permeability test in the hole after coring wall mass, (4) analyzing the characteristics of basic components and their profiles through the series of chemical experiments and (5) deciding the general distribution patterns from the chromatograms using GC-MS, it could be identified that watertight and cutting-off the leachate of wall mass constructed in underground was very effective. Therefore, it is concluded that five types of tests suggested in this study can judge the effect of cutting-off the leakage or infiltration of very high concentrated leachate from the waste landfill.

• Asian-Australasian Journal of Animal Sciences
• /
• v.9 no.2
• /
• pp.223-229
• /
• 1996

This experiment was conducted to investigate the protein sparing effect of rumen protected lysine(RPLys) and methionine hydroxyl analogue(MHA) in sheep. The treatments were $T_1$ (CP 15% + RPLys 0%), $T_2$ (CP 12% + RPLys 0%), $T_3$ (CP 12% + RPLys 0.4%) and $T_4$ (CP 12% + RPLys 0.4% + MHA 0.3%). Ruminal characteristics, in situ and in vitro digestibility and nitrogen retention rate were measured in sheep receiving different combinations of dietary supplement. The results are summarized as follows: 1. Ruminal pH and VFA concentrations were not affected by the treatments. Ruminal ammonia-N concentration was high in sheep fed diets $T_2$, $T_3$ and $T_4$ with the highest value in the $T_4$ treatment(p<0.05). 2. The digestibilities of dry matter and organic matter were not affected by the treatments. 3. Nitrogen losses through feces and urine were the highest with $T_1$ (p<0.05) and nitrogen retention rates of groups $T_1$, $T_2$, $T_3$ and $T_4$ were 18.6, 32.4, 35.5 and 27.5% of nitrogen intake, respectively, indicating that RPLys supplementation improved nitrogen retention in sheep.