• Journal of the korean society of oceanography
• /
• v.31 no.4
• /
• pp.196-206
• /
• 1996

Vertical profiles of the chlorophyll ${\alpha}$, phytoplankton abundance, nutrients and sigma-t were compared with the vertical distribution of phytoplankton species in conjunction with $^{14}$C primary production in the Southern Waters of the East Sea, Korea. In the upper mixed layer the water column was only weakly stratified and ambient nitrogenic nutrient concentrations were markedly depleted. Dissolved silicate seemed to be another limiting nutrient in the surface layer. The occupation of different water depths by several dominant diatom species was well explained by the degree of silicification of each cell and the silicate concentration of ambient seawater. Subsurface chlorophyll maxima were continuously observed in the lower parts of the euphotic layer and the depth coincided with nutricline, supporting our view that chlorophyll maximum was sustained partially by enhancement of in situ growth of phytoplankton and partially by increase of cellular chlorophyll content. The persistence of chlorophyll maximum layer was attributed to the physiological adaptation of the phytoplankters to low light intensities and to the utilization of regenerated nutrients. Integrated water column production of organic matter by photosynthesis appeared to be better related to phytoplankton cell division than to the cell growth in terms of biosynthesis of pigments and other intracellular components.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.1
• /
• pp.57-71
• /
• 2009

Crop-livestock mixed farming systems depend on the efficiency with which nutrients are conserved and recycled. Home-grown forage is used as animal feed and animal excretions are applied to cultivated crop lands as manure. The objective of this study was to develop a mixed farming system model for dairy cattle in Japan. The model consisted of four sub-models: the nutrient requirement model, based on the Japanese Feeding Standards to determine requirements for energy, crude protein, dry matter intake, calcium, phosphorus and vitamin A; the optimum diet formulation model for determining the optimum diets that satisfy nutrient requirements at lowest cost, using linear programming; the herd dynamic model to calculate the numbers of cows in each reproductive cycle; and the whole farm optimization model to evaluate whole farm management from economic and environmental viewpoints and to optimize strategies for the target farm or system. To examine the model' validity, its predictions were compared against best practices for dairy farm management. Sensitivity analyses indicated that higher yielding cows lead to better economic results but higher emvironmental load in dairy cattle systems integrated with forage crop production.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.11
• /
• pp.1607-1614
• /
• 2011

This trial was conducted to determine the effects of including canola protein concentrate in diets fed to broiler chickens on nutrient digestibility and broiler performance (0-21 days). A total of 180, day-old, male broiler chicks weighing an average of 52.8${\pm}$0.6 g were assigned to one of six dietary treatments in a completely randomized design. The control diet was based on corn and soybean meal and contained 15% canola meal. The experimental diets contained 3, 6, 9, 12 or 15% canola protein concentrate added at the expense of canola meal. There were five birds per pen and six replicate pens per treatment. Feed and water were available ad libitum throughout the 21-day experiment. Chromic oxide (0.35%) was added to all diets as a digestibility marker and was fed throughout the experimental period. The digestibility of dry matter, energy and phosphorus increased linearly (p<0.01) with increasing levels of canola protein concentrate. Although nutrient digestibility was higher for birds fed diets containing canola protein concentrate, these improvements did not translate into improvements in broiler performance. Weight gain was unaffected (p = 0.24) by level of canola protein concentrate. Feed intake was significantly increased (p<0.01) with the result that feed conversion tended to be poorer (p = 0.07) for birds fed diets containing canola protein concentrate. Mortality was also unaffected (p = 0.56) by dietary treatment.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.11
• /
• pp.1560-1568
• /
• 2011

This study was conducted to evaluate the yield, nutrient characteristics, ruminal solubility, degradability and disappearance of spent mushroom (Agaricus bisporus) substrates for ruminants. The annual yield of spent Agaricus bisporus substrates was measured to be about 210,000 tons (M/T) in South Korea. The surface soil-removed spent substrates had nutritional characteristics of high crude ash (375 g/kg) and Ca (32 g/kg), medium protein (134 g/kg CP), and high fiber (384 g/kg NDF on a DM basis). Compared with initial mushroom substrates, spent mushroom substrates had twice higher (p<0.0001) CP content and 22.0% lower (p<0.0001) NDF content on an organic matter basis. Compared with raw rice straw, spent rice straw had much higher (p<0.05) predicted ruminal degradabilities and disappearances of DM and CP and a little lower (p<0.05) predicted degradability and disappearance of NDF. In conclusion, the general feed-nutritional value of spent mushroom (Agaricus bisporus) substrates appeared to improve after cultivation of mushrooms.

• Journal of Animal Science and Technology
• /
• v.62 no.5
• /
• pp.605-613
• /
• 2020

This study was conducted to evaluate the effects of dietary supplementation of plant flavonoid (quercetin) on immune parameters, growth performance, and nutrient digestibility in growing pigs challenged with Escherichia coli lipopolysaccharide (LPS). A total of 40 crossbred ([Landrace × Yorkshire] × Duroc) growing pigs; initial body weight (BW) of 26.95 ± 1.26 kg were used in a six-week experimental trial. Pigs were randomly allocated into one of four treatment groups in a 2 × 2 factorial arrangement with the following factors; without LPS challenge and with LPS challenge (day 21) supplemented with or without 0.1% flavonoid according to BW (2 replicate pens per treatment with 2 gilts and 3 barrows per pen). The single-dose LPS (100 ug / kg BW) injection showed trends tended to be increased in interleukin-6 (IL-6) after 2 h and 6 h of challenge compared with unchallenged pigs. However, other measured immune indices (white blood cell, immunoglobulin G, lymphocyte, and tumor necrosis factor), growth performance, and nutrient digestibility were not significantly different between challenged and non-challenged animals. The supplementation of flavonoid significantly increased (p < 0.05) average daily gain (ADG) during day 0-21, tended to increase dry matter and nitrogen digestibility, significantly reduced IL-6, increased Ig-G and WBC concentrations and increased lymphocytes percentage regardless of LPS challenge.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.1
• /
• pp.108-115
• /
• 2013

The effects of dietary Coptis chinensis herb extract (CHE) on growth performance, blood characteristics, nutrient digestibility and meat quality of growing-finishing pigs were investigated in an 18-wk feeding trial. A total of 36 Landrace${\times}$Yorkshire-Duroc pigs with an initial body weight of $20{\pm}1.0$ kg were randomly assigned to 3 dietary treatments with 6 replications per treatment and 2 pigs per pen. A maize-soybean meal-based diet was formulated as a control diet and other treatment diets were supplemented with 0.5, or 1 g CHE/kg, respectively. After the feeding period, meat samples were collected from those pigs that had reached the market BW. During the experimental periods, growth performance and apparent total tract digestibility of dry matter and nitrogen were unaffected (p>0.05) by the dietary supplementation of CHE. Plasma erythrocytes counts were increased (Linearly, p<0.05) in response to application of CHE at the end of the experiment. Moreover, pigs fed the CHE diets had better (p<0.05) meat color, pH and water holding capacity (WHC) than pigs fed the control diet. In conclusion, dietary supplementation with CHE could increase blood erythrocytes counts and improve meat quality in growing-finishing pigs but not improve growth performance.

• Asian-Australasian Journal of Animal Sciences
• /
• v.10 no.4
• /
• pp.371-377
• /
• 1997

Objective of the present study were to investigate effects of different levels of concentrate in complete rations on nutrient digestibilities and ruminal fermentation in sheep and growth performance in Korean native bulls. Increasing levels of concentrate (35, 50, 65, and 80% of complete rations) improved digestibilities of dry matter (DM), crude protein (CP) and ether extract (EE) without affecting digestibility of neutral detergent (NDF) and acid detergent fiber (ADF). Increasing levels of concentrate decreased ruminal fluid pH but increased concentrations of $NH_3-N$, propionic acid, and total volatile fatty acids (VFA). Both the disappearance rates of DM and nitrogen (N) in an in sacco study were linearly increased as the levels of concentrate in complete rations increased. Meanwhile, increasing levels of concentrate in complete rations improved growth rate and feed conversion ratio in Korean native bulls. In conclusion, the complete rations containing 80% concentrate showed better digestibility and energy supply than those of the lower levels (35, 50 and 65%) of concentrate of the rations, resulting in improved growth performance of Korean native bulls.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.5
• /
• pp.589-599
• /
• 2007

This study was conducted to investigated the removal efficiency of BOD and nutrient for the treatment of low strength municipal wastewater by a biological nutrient removal system. In this experiment, the effect of operating parameter including HRT of 7.0hr, BOD/TN ratios of 2.62~4.08, internal recycle of 50~300%, and return sludge of 50~100%, were studied during winter season. Efficiencies of organic matter and T-P removal and denitrification were not significantly affected by the change of temperature in winter season. However, the specific nitrification rate and nitrification efficiency decreased at low temperature. Besides, denitrification efficiencies increased with increasing BOD/TN ratios. It was also found that the internal recycle and return sludge ratio below 50% is required for the effective denitrification of low strength municipal wastewater. With operating mode 4 of the optimum, the effluent BOD, T-N and T-P concentration were obtained to average 5.8, 14.6, and 0.84 mg/L, respectively. The temperature-activity coefficient (${\theta}$) of specific nitrification rate, specific denitrification rate and specific phosphorus uptake rate were obtained 1.044, 1.017, 1.028, respectively.

• Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.81-89
• /
• 2020

In the forest ecosystems, litterfall is an important component of the nutrient cycle that regulates the accumulation of soil organic matter (SOM), the input and output of the nutrients, nutrient replenishment, biodiversity conservation, and other ecosystem functions. Therefore, a profound understanding of the major processes (litterfall production and its decomposition rate) in the cycle is vital for sustainable forest management (SFM). Despite these facts, there is still a limited knowledge in tropical forest ecosystems, and further researches are highly needed. This shortfall of research-based knowledge, especially in tropical forest ecosystems, may be a contributing factor to the lack of understanding of the role of plant litter in the forest ecosystem function for sustainable forest management, particularly in the tropical forest landscapes. Therefore, in this paper, I review the role of plant litter in tropical forest ecosystems with the aims of assessing the importance of plant litter in forest ecosystems for the biogeochemical cycle. Then, the major factors that affect the plant litter production and decomposition were identified, which could direct and contribute to future research. The small set of studies reviewed in this paper demonstrated the potential of plant litter to improve the biogeochemical cycle and nutrients in the forest ecosystems. However, further researches are needed particularly on the effect of species, forest structures, seasons, and climate factors on the plant litter production and decomposition in various types of forest ecosystems.

• Asian-Australasian Journal of Animal Sciences
• /
• v.9 no.2
• /
• pp.155-158
• /
• 1996

Seventy two Black Bengal goats on road side grass based diet were fed on 0, 20, 40, 80, 100 or 120 g of fish meal (FM)/goat/day with or without ad libitum access to urea molasses block(UMB). The purpose was to assess the interaction of undegradable protein (UDP) and fermentable nitrogen(N) supplementation on feed intake, nutrient digestibility and growth of goats. Live weight gain of goats increased linearly with the increasing of dietary fish meal as an undegradable protein source. With the increasing level of fish meal the live weight gain(g/day) was 17, 23, 46, 48, 48 and 52 with urea molasses block and 12, 21, 31, 49, 47 and 47 without urea molasses block. It was concluded that the beneficial effects of urea molasses feeding to accelerate the dry matter intake, TDN intake and nutrient digestibility observed could not be exploited in terms of live weight gain.