• ALGAE
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• v.31 no.3
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• pp.257-266
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• 2016

Nitrogen is one of the most critical nutrients affecting cell growth and biochemical composition of microalgae, ultimately determining the lipid or carbohydrate productivity for biofuels. In order to investigate the effect of nitrogen sources on the cell growth and biochemical composition of the marine microalga Tetraselmis sp., nine different N sources, including NaNO₃, KNO₃, NH₄NO₃, NH₄HCO₃, NH₄Cl, CH₃COONH₄, urea, glycine, and yeast extract were compared at the given concentration of 8.82 mM. Higher biomass concentration was achieved under organic nitrogen sources, such as yeast extract (2.23 g L⁻¹) and glycine (1.62 g L⁻¹), compared to nitrate- (1.45 g L⁻¹) or ammonium-N (0.98 g L⁻¹). All ammonium sources showed an inhibition of cell growth, but accumulated higher lipids, showing a maximum content of 28.3% in ammonium bicarbonate. When Tetraselmis sp. was cultivated using yeast extract, the highest lipid productivity of 36.0 mg L⁻¹ d⁻¹ was achieved, followed by glycine 21.5 mg L⁻¹ d⁻¹ and nitrate 19.9 mg L⁻¹ d⁻¹. Ammonium bicarbonate resulted in the lowest lipid productivity of 14.4 mg L⁻¹ d⁻¹. The major fatty acids in Tetraselmis sp. were palmitic, oleic, linoleic and linolenic acids, regardless of the nutritional compositions, indicating the suitability of this species for biodiesel production.

• Nutrition Research and Practice
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• v.11 no.2
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• pp.147-154
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• 2017

BACKGROUND/OBJECTIVES: Assessing changes in energy intake and dietary sources is important to understand trends in the prevalence of obesity. Thus, we examined trends in energy intake and its nutrient and food sources in Korean adults from 1998 through 2015. SUBJECTS/METHODS: This study included 70,769 subjects aged ${\geq}19$ years who completed a nutrition survey. Subject data were obtained from the 1998, 2001, 2005, 2007-2009, 2010-2012, and 2013-2015 Korea National Health and Nutrition Examination Surveys. Dietary intake was assessed by a 1-day 24-hour recall method. RESULTS: In men, the daily energy intake significantly increased from 2,196 kcal in 1998 to 2,489 kcal in 2013-2015 (P for trend < 0.0001). However, the daily energy intake among women did not change significantly over the same period (P for trend = 0.5772). The percentages of energy intake from animal foods (e.g., meat and milk) and beverages increased during the study period in both men and women. However, the percentage of energy intake from plant foods decreased due to a marked decrease in the intake of white rice. Changes in food sources of energy intake led to changes in the nutrient sources of energy intake; for example, the increase of energy intake from fat and decrease of energy intake from carbohydrate. CONCLUSIONS: This study suggests that since 1998, energy intake has increased among Korean adult men, but not among women. However, the composition of food and nutrient sources of energy intake has changed in both men and women. Energy intake and its nutrient and food sources should continue to be monitored regularly in the Korean adult population.

• Nutrition Research and Practice
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• v.13 no.4
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• pp.323-332
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• 2019

BACKGROUND/OBJECTIVES: The aim of this study was to analyze specific foods influencing absolute nutrient intake and between-person variations of nutrient intake among Korean preschoolers. SUBJECTS/METHODS: This study included 2,766 participants aged 1-5 years in the 2009-2013 Korea National Health and Nutrition Examination Surveys. Dietary data were obtained from a 24-h dietary recall method. Major food sources of absolute nutrient intake were evaluated based on percent contribution of each food. To assess the contribution of specific foods to between-person variations in nutrient intake, stepwise multiple regressions were performed and cumulative $R^2$ was used. RESULTS: White rice and milk were main food sources of energy, protein, carbohydrate, phosphorus, iron, potassium, thiamin, riboflavin, and niacin. The percentage of fat contributed by milk was 21.3% which was the highest, followed by pork, soybean oil, and egg. White rice accounted for 25% and 40% of total variability in total energy and carbohydrate intakes, respectively. About 39% of variation in calcium intake was explained by milk while 40% of variation in phosphorous intake was explained by cheese. The top 10 foods contributing to between-person variations in nutrient intakes were similar with food items that mainly contributed to absolute nutrient intakes. The number of foods explaining 90% of absolute amounts of nutrient intakes varied from 28 for vitamin A to 80 for iron. CONCLUSIONS: This study identified specific foods that contributed to absolute nutrient intakes and between-person variations in nutrient intakes among Korean preschoolers. Our findings can be used to develop dietary assessment tools and establish food-based dietary guidelines for young children.

• Korean Journal of Microbiology
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• v.20 no.4
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• pp.161-172
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• 1982

In order to compare the metabolic activities of methanol utilizing bacteria, Pseudomonas sp. grown in different carbon sources, changes in respiratory activities, prinicipal enzyme activities for the energy metabolism, and the macromolecular compositions of the cells grown on methanol or glucose were measured. 1. The respiratory activity of cells grown on methanol was higher than that of cells grown on glucose, while glucose exhibited the highest $O_2-consumption$ rate among the different respiratory substrates. 2. TRhe activity of hydroxy pyruvate reductase which participates in serine pathway was high in the cells grown on methanol. However, activities of NAD-linked alcohol dehydrogenase, formaldehyde dehydrogenase and formate dehydrogenase were slightly lower in the cells grown on glucose thant on methanol. 4. For succinic dehydrogenase and malic dehydrogenase which take part in TCA cycle, the specific activities were higher in the cells grown on methanol than in those grown on glucose. No activity of glucose-6-phosphate dehydrogenase, which participates in pentose monophosphate shunt, was detectable in the cells grown on either carbon sources. 5. Protein contents of the cells grown on methanol increased relatively compared with those of the cells grown on glucose. However, there are no changes in the contents of carbohydrate and nucleic acid.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.635-642
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• 1997

This experiment was conducted to determine apparent ileal and fecal digestibilities of some grains for young pigs (15.6 kg BW). Ileal and fecal digestibility of corn, milo, wheat, barley, rice and tapioca were measured with pigs fitted with simple ileal T-cannula. Rice was the highest (p < 0.05) and tapioca was the lowest (p < 0.05) in the digestibilities of gross energy. For the crude protein digestibilities, rice, barley and wheat were higher (p < 0.05) than corn, milo and tapioca. The average ileal digestibilities of essential amino acids (AAs) were 89.9, 85.8, 81.5, 80.9, 80.2 and 76.3% for those fed rice, barley, milo, wheat, corn and tapioca diets, respectively. Regardless of the dietary carbohydrate sources, among the dispensable amino acids, glycine had lowest digestibility except for barley and milo. The apparent ileal digestibility of lysine and methionine were 90.7, 94.0% in rice, 88.3, 86.5% in barley and 86.3, 82.3% in wheat. The apparent fecal digestibility of average essential AAs were 90.8, 89.9, 87.7, 85.1, 82.5 and 77.9% in pigs fed the rice, barley, wheat, corn, milo and tapioca diets, respectively. The fecal digestibilities of essential AAs and nonessential AAs, in general, were higher than the ileal digestibilities, which indicating a loss of nitrogenous components in the cecum and colon. For all AAs, differences between ileal and fecal amino acid digestibilities ranged from 0.0 (valine) to 5.8 (threonine) in rice, 0.1 (arginine) to 14.5 (glycine) in barley, 2.8 (lysine) to 12.4 (glycine) in wheat, 1.0 (isoleucine) to 12.9 (glycine) in corn, 0.2 (serine, glutamic acid) to 6.5 (methionine) in milo and 0.5 (valine) to 22.1 (glycine) percentage units in tapioca diets. In conclusion, whether it is ileal or fecal, rice and barley appeared to be excellent alternative carbohydrate sources for young pigs in terms of AAs digestibility. However, energy value and cost for each grain should be considered when formulating diets.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.212-219
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• 1991

Four species of yeast, Saccharomyces cerevisiae, Candida utilis, Saccharomycopsis flbuligera, and Schwanniomyces castellii were evaluated for their ability to bioconvert potato processing waste water into microbial protein and the resulting single-cell proteins were evaluated as protein sources for rainbow trout, using in vitro analyses. The studies indicated that Schwanniomyces castellii, which utilizes starch dircetly and converts it into cell mass efficiently, was suitable for the bioconversion. In the single-stage continuous bioconversion, the yield S. castellii cell mass, which contained approximately 37% protein, was 77%, at dilution rate 0.25 $h^{-1}$. Reduction of total carbohydrate was 81%. During batch fermentations, cell mass yield was about 72% and total carbohydrate reduction was 81%. Among the yeasts tested, S. castellii possessed the most fragile cell wall and had a favorable amino acid profile for salmonid fish; protein score of 86% (Met). In an in vitro pepsin digestibility test 80% digestibility (23~38% above control) was observed when cells were pre-heated in a steam bath for 30 min. Results presented should be regarded as being preliminary in nature because they were derived from single experiments.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1061-1070
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• 2003

The purpose of this study was to investigate differences in the diet with the amount and the qualitative assessment of nutrient intakes by the economic level. Data from the 1998 Korean Health and Nutrition Survey were used. Using the poverty line based on the 1998 Korean minimum cost of living, Subjects (n = 10400) were classified into high class (36.1％), middle class (40.7％) and low class (23.1％). Chi-square-test and Analysis of Variance following Duncan's multiple range test were used to test the difference in nutrient intake pattern among three groups ($\alpha$ = 0.05). The amount of nutrient intake and nutrient intake adequacy were statistically different by the economic level (p<0.01). The ratio of energy intake from carbohydrate is higher than the criteria of WHO recommendation in all economic levels. Especially people in the low class depended much on the carbohydrate for the energy intake. The ratio of energy from the protein and fat are lower in the middle and low class than that of the high class. The Intake level of calcium and vitamin B$_2$ were lower than those of the Recommended Dietary intake level, regardless of economic status. It also showed differences in major food sources of nutrients by the economic level Consequently, it seems that the nutrition policy and program should be prepared according to their economic status. Also, there should more detailed studies to find out the nutrient intake pattern, their determinant, and health consequences.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.17-18
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• 2003

Although flounder is one of the most important marine fish for aquaculture in Korea, feeding the flounder in commercial farms depends mainly on moist pellet in which over 70% frozen fishes (e.g. frozen horse mackerel) are incorporated in its formulation. Therefore, for further expansion of flounder farming, it is essential to employ practical formulated feeds that can support reasonable growth. Development of nutritionally balanced and cost-effective feeds is dependant on the information about nutritional requirement and feed utilization of the species. Nutrient and energy source in feed are needed for the growth and maintenance of fish. Protein is probably the most important nutrient affecting fish growth and feed cost. Therefore, it is essential to determine the optimum dietary protein level for the growth of fish, both its high proportion in the feed and because it is the main factor in determining feed cost. Dietary energy level is also critical because protein source in the feed is utilized as an energy source when the feed deficient in energy is fed to fish, whereas when the feed excess in energy is fed to fish, feed consumption decreased and resulted in growth reduction due to lack of other necessary nutrients for normal growth. Improper dietary protein, energy levels and/or their ratio will lead to an increase of fish production cost and deterioration of water quality resulting from wasted feed; thus, they are important in formulating commercial feed. Dietary lipids play important roles in providing energy and essential fatty acid for normal growth and survival of fish. Although carbohydrates are not essential nutrients for carnivorous fish, these compounds play important roles as a low-cost energy source for protein sparing and also as a feed binder. Nutrition researches for flounder have identified its requirements of protein, lipid and essential fatty acid, vitamin, and minerals for normal growth. Other studies have also been carried out to investigate the utilization of the protein, lipid and carbohydrate sources. Based on these nutritional information obtained, practical feed formulations have been studied for improve aquaculture production of flounder. The results of the researches on utilization of dietary protein, lipid and carbohydrate by flounder are discussed in this review.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1513-1520
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• 2009

Forty-six Holstein heifers were used in a completely randomized design and assigned to 1 of 2 treatments to evaluate the effects of 2 diets varying in ruminal fermentable carbohydrate sources, namely ground corn (GC) and rolled wheat (RW), on metabolism and performance of primiparous cows in the periparturient period. The heifers were fed diets as a total mixed ration (TMR) with similar energy and crude protein content including i) 18.57% GC, or ii) 18.57% RW from -24.13${\pm}$7.73 d relative to expected calving until calving. After calving, all animals received the same lactation diet until 28 d. Animals were group fed from the beginning of the study to -7 d relative to expected calving, fed individually from d -7 to 7 days in milk (DIM), and again group fed to 28 DIM. The pre-partum diets affected (p<0.05) dry matter intake (DMI), energy intake, energy balance (EB) and urinary pH during the last week pre-partum. There was no effect of pre-partum carbohydrate source on overall plasma concentration of glucose, nonesterified fatty acid (NEFA), $\beta$-hydroxybutyrate (BHBA), albumin, triglyceride (TG), cholesterol, aspartate aminotransferase (AST), insulin, and cortisol during the periparturient period. Cows fed the RW diet during the pre-partum period had greater calcium for the first week (p<0.05) and during 28 d (p = 0.08) of lactation compared with heifers fed the GC diet. Primiparous cows fed the RW diet produced greater milk protein content and yield (p<0.05). Primiparous cows fed the RW diet had lower milk urea nitrogen (MUN) and somatic cell count (SCC) than cows fed the GC diet (p<0.05). The results of this study show that feeding pre-partum diets with a rapidly fermentable source of starch but low energy content can improve animal metabolism and performance and smooth the transition of primiparous Holstein cows from gestation to lactation.

• KSBB Journal
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• v.25 no.1
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• pp.47-54
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• 2010

The mycelial dispersed growth of Cordyceps sinensis was optimized in submerged batch culture at initial pH of 5.0, 150 rpm, and $25^{\circ}C$. The morphological data showed much more dispersed growth of C. sinenesis at initial pH of 5.0. Also, projected area, main hyphal length and number of tips for the mycelial growth of initial pH 5.0 were higher than those of other initial pHs. The industrial medium for mycelial production of C. sinensis was determined to be molasses of 100 g and crushed brewery yeast of 10 g per liter as carbon and nitrogen sources, respectively. With these culture conditions, the maximum production of mycelia was approximately 30.0 g per liter by batch culture in 5-liter jar fermenter with no controlled pH. This result suggests that large-scale mycelia production of C. sinensis may be possible in submerged batch culture. The hot water extract of mycelia from C. sinensis was mainly composed of 83.0% carbohydrate, 11.8% protein, 1.9% lipid, and 2.4% ash and there were present glucose, mannose, galactose, and arabinose as molar ratio of 8.79 : 2.59 : 1.34 : 1.0 in the carbohydrate, respectively. In the experiment using spleen cell and macrophage, the extract showed potent mitogenic and immuno-stimulating activities and among various components, an important factor that contribute to the immunological activities was turned out to be carbohydrate moiety.