• Journal of Species Research
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• v.2 no.2
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• pp.159-166
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• 2013

Typical of large, oligotrophic lakes, Lake H$\ddot{o}$vsg$\ddot{o}$l, Mongolia, exhibits complex morphometry which should support a spatially heterogeneous community of benthic macroinvertrates. The lake also exhibits a broad range of land uses. Based on the variation in land use and complex physical habitat of the lake (e.g. substrate variation and presence of affluent streams in bays), we asked two questions. First, does density of total benthic macroinvertebrates vary between different bays in Lake H$\ddot{o}$vsg$\ddot{o}$l? Second, does density of individual benthic taxa vary by bay? Samples collected in 1997, the last year for benthic sampling of the lake, were designed to test for variation in macroinvertebrate density between bays and can now be used to establish baseline variation in density for future studies. A total of 56 Ponar grab samples were analyzed from six bays in Lake H$\ddot{o}$vsg$\ddot{o}$l. Results of a general linear model analysis of variance showed that total density of macroinvertebrates varied only slightly between bays of the lake, but that most individual taxa showed significant variation between bays. Variation in density for most taxa was linked to substrate composition rather than other geographic or physical variables in the lake. Recent increases in grazing intensity and ecotourism along the shores should be managed to reduce the nutrient load into the lake to avoid impairment of the benthic biota of this unique, ancient ecosystem.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1598-1604
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• 2017

Objective: The present study investigated the litter performance of multiparous sows fed 3% and 6% densified diets at farrowing to weaning during summer with mean maximum room temperature of $30.5^{\circ}C$. Methods: A total of 60 crossbred multiparous sows were allotted to one of three treatments based on body weight according to a completely randomized design. Three different nutrient levels based on NRC were applied as standard diet (ST; metabolizable energy, 3,300 kcal/kg), high nutrient level 1 (HE1; ST+3% higher energy and 16.59% protein) and high nutrient level 2 (HE2; ST+6% higher energy and 17.04% protein). Results: There was no variation in the body weight change. However, backfat thickness change tended to reduce in HE1 in comparison to ST treatment. Dietary treatments had no effects on feed intake, daily energy intake and weaning-to-estrus interval in lactating sows. Litter size, litter weight at weaning and average daily gain of piglets were significantly greater in sows in HE1 compared with ST, however, no difference was observed between HE2 and ST. Increasing the nutrient levels had no effects on the blood urea nitrogen, glucose, triglyceride, and creatinine at post-farrowing and weaning time. The concentration of follicle stimulating hormone, cortisol and insulin were not affected by dietary treatments either in post-farrowing or weaning time. The concentration of blood luteinizing hormone of sows in ST treatment was numerically less than sows in HE2 treatment at weaning. Milk and colostrum compositions such as protein, fat and lactose were not affected by the treatments. Conclusion: An energy level of 3,400 kcal/kg (14.23 MJ/kg) with 166 g/kg crude protein is suggested as the optimal level of dietary nutrients for heat stressed lactating sows with significant beneficial effects on litter size.

• Journal of Aquaculture
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• v.8 no.4
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• pp.285-294
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• 1995

In Bouin polder, one of the oyster culture zone on landbase in France, artificial substrate was suspended every week to study the variation of the biomass of benthic microalgae as the chlorophyll a. The meteorological and physico-chemical factors in sea water were studied by analysing the correlationship, correlation circle and principal component of these factors. Among the meteorological factors such as insolation, precipitation and wind, insolation was one of the most prominant factors associated with the increase of water temperature, salinity, pH and biomass but with the decrease of turbidity, dissolved oxygen and nitrate. Nitrate was the main contributor for the variation of biomass among the other nutrient components, while phosphate and silicate increased in summer when the biomass increased.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.48-48
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• 2014

Arbuscular Mycorrhizal Fungi(AMF) is widespread symbiont forming mutualistic relationship with plant root in terrestrial forest in ecosystem. They provide improved absorption of nutrient and water, and enhance the resistance against plant pathogen or polluted soil, therefore AM fungi are important for survival and maintaining of individual or community of plant. For last decade, many studies about the functional variation of AM fungi on host plant growth response were showed that different geographic isolates, even same species, have different effect on host plant. However, little was known about functional variation of AM fungal isolates originated single population, which provide important insight about intraspecific diversity of AMF and their role in forest ecosystem. In this study, four AM fungal isolates of Rhizophagus clarus were cultured in vitro using transformed carrot (Daucus carota) root and they showed the difference between isolates in ontogenic characteristics such as spore density and hyphal length. The plant growth response by mycorrhizas were measured also. After 20 weeks from inoculation of these isolates to host plants, dry weight, Root:Shoot ratio, colonization rates and N, P concentration of host plant showed host plant was affected differently by AM fungal isolates. This results suggest that AM fungi have high diversity in their functionality in intraspecific level, even in same population.

• Journal of Forest and Environmental Science
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• v.29 no.1
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• pp.29-37
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• 2013

The study was carried out in two different forest types viz., Banj oak and Chir pine forests to assess the variation in forest species composition and soil properties along altitudinal gradients in the Garhwal Himalayas. The results of the study showed that between the forests soil moisture was higher in Banj oak forest because of closed canopy and dense forest compared to Chir pine forest. The sand particles were reported higher in Banj oak forest which might be due to the addition of organic matter favouring coarse structure of soil, helping in holding maximum water in soils. However in the Chir pine forest low amount of soil organic matter and presence of clayey soil, develops soil compactness which reduces the penetration of water resulting in high soil bulk density. The higher accumulation of litter and presence of moisture in Banj oak forest favours higher nutrient level of nitrogen, phosphorus and potassium compared to Chir pine forest. The soil organic carbon also reduced with increasing altitude at both gradients. While bulk density has reverse trend with soil organic carbon in both the forests at different peaks of same region. In Banj oak forest, the highest density and total basal cover was reported 1,100 tree $ha^{-1}$ and 58.86 $m^2\;ha^{-1}$ respectively. However, the highest values of density and total basal cover of Chir pine forest was 560 tree$ha^{-1}$ and 56.94 $m^2\;ha^{-1}$ respectively. The total density and basal cover of both the forests reduced with increasing altitude. The study concludes that Banj oak forest has better nutrient cycling ability, well developed foest floor and has a greater protective and productive features compared to the Chir pine forest which is without lower vegetation cover and having only pine litter accumulation which does not allow any other species to grow.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.1
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• pp.3-12
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• 2018

Objective: DNA methylation plays a major role in regulating the expression of genes related to traits of economic interest (e.g., weight gain) in livestock animals. This study characterized and investigated the functional inferences of genome-wide DNA methylome in the loin (longissimus dorsi) muscle (LDM) of swine. Methods: A total of 8.99 Gb methylated DNA immunoprecipitation sequence data were obtained from LDM samples of eight Duroc pigs (four pairs of littermates). The reference pig genome was annotated with 78.5% of the raw reads. A total of 33,506 putative methylated regions (PMR) were identified from methylated regions that overlapped at least two samples. Results: Of these, only 3.1% were commonly observed in all eight samples. DNA methylation patterns between two littermates were as diverse as between unrelated individuals (p = 0.47), indicating that maternal genetic effects have little influence on the variation in DNA methylation of porcine LDM. The highest density of PMR was observed on chromosome 10. A major proportion (47.7%) of PMR was present in the repeat regions, followed by introns (21.5%). The highest conservation of PMR was found in CpG islands (12.1%). These results show an important role for DNA methylation in species- and tissue-specific regulation of gene expression. PMR were also significantly related to muscular cell development, cell-cell communication, cellular integrity and transport, and nutrient metabolism. Conclusion: This study indicated the biased distribution and functional role of DNA methylation in gene expression of porcine LDM. DNA methylation was related to cell development, cell-cell communication, cellular integrity and transport, and nutrient metabolism (e.g., insulin signaling pathways). Nutritional and environmental management may have a significant impact on the variation in DNA methylation of porcine LDM.

• Journal of Animal Science and Technology
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• v.58 no.6
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• pp.22.1-22.15
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• 2016

Background: Dietary manipulation is a common practice to mitigate gaseous emission from livestock production facilities, and the variation of fat level in the diet has shown great influence on ruminal volatile fatty acids (VFA) and enteric methane generation. The changes in dietary fat levels influence rumen chemistry that could modify manure nutrient composition along with odor and gaseous emissions from manure management facilities. Methods: A field experiment was carried out on beef cattle feedlots to investigate the effect of four levels of dietary fat concentrations (3 to 5.5 %) on the manure composition and gaseous emissions (methane-$CH_4$, nitrous oxide-$N_2O$, carbon dioxide-$CO_2$ and hydrogen sulfide-$H_2S$) from the feedlot pen surface. The experiment was carried out over a 5-month period from June to October during North Dakota's summer-fall climatic condition. Air and manure sampling was conducted five times at a 20-30 day intervals. Results: Overall, this research indicated that fat levels in diet have no or little effect on the nutrient composition of manure and gaseous emission from the pens with cattle fed with different diet. Though significant variation of gaseous emission and manure composition were observed between different sampling periods, no effect of high fat diet was observed on manure composition and gaseous emission. Conclusions: It can be concluded that addition of fat to animal diet may not have any impact on gaseous emission and manure compositions.

• Journal of the Korean GEO-environmental Society
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• v.10 no.1
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• pp.43-48
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• 2009

This study was performed to investigate the characteristics of nutrient removal by Sequencing Batch Reactor (SBR) system, which could achieve high removal efficiencies of nitrogen and phosphorus and make it possible convenient management and operation. In this study, dissolved oxygen (DO), chemical oxygen demand (COD), nitrogen, and phosphorus in SBR system were examined by variation of anoxic-oxic phase repetition in order to optimize an operational method. The 1~4 times of anoxic-oxic phases (Run 1~4) were repeated during 1 cycle operation period. As the repetition frequency increased, it was more difficult to maintain DO condition enough for denitrification. The SBR system showed high COD removal efficiency more than 91% regardless of operational condition. About 68% of nitrogen removal rate was obtained in conditions of 2 or 3 times repetition of anoxic phases, in which NOx-N among discharged total nitrogen account for more than 99%. Approximately 40% of phosphorus was eliminated in the conditions of 1~3 times of anoxic phase repetition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.1-8
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• 2006

To investigate the variation of marine environments due to set up of artificial structure, we carried out field observations. High temperature and salinity waters near the south frontal area were distributed clearly in the southeastern part of study area during summer season The variation of current structure was also occurred around study area where artificial structure set up. In 2005 after set up of artificial structure, the nutrient concentration increased greater than that in 2002 before set up artificial structures. To illustrate the characteristics of marine environment due to set up of artificial structure, quantitative analyses on the effect of artificial structure are important.

• Journal of Environmental Science International
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• v.12 no.4
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• pp.427-437
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• 2003

An evaluation of the application of SBR and biofilm en small sewerage system was conducted. A newly developed small sewerage system, using SBR, was successfully applied to the nutrient treatment using municipal wastewater. The system was consisted of 6 compartments. Two systems, with SBR (A type) or without SBR (B type), were compared by several parameters (COD, SS, T-N, NH$_4$$\^$+/-N, NO$_3$$\^$-/-N, NO$_2$$\^$ -/-N, alkalinity, pH, DO) in all experimental periods. Also, the time variation of several parameters (DO, pH, NH$_4$$\^$+/-N, NO$_3$$\^$-/-N NO$_2$$\^$-/-N) was examined in a SBR applied sewerage system. T-N removal efficiency of B type Was higher than that Of A type by the effect of nitrification and denitrification even though the COD removal efficiencies were similar. In aeration stage, the pH was decreased from 6.4 to 6.3 within 1 h and increased to 6.65 at the end of aerobic stage, and pH was decreased to 6.2 in non-aeration stage, and these phenomena were explained. The effects of nitrification and denitrification were compared in A type and B type sewerage system, and the typical nitrification and denitrification were observed in B type sewerage system.