• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.326-331
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• 2005

A rumen simulated continuous culture (RSCC) system was used to study the influence of supplementation of the three different types of protein sources such as urea, casein and soy protein on rumen microbial synthesis in terms of rumen microbial synchronization. The urea treatment showed the highest pH value. Ammonia nitrogen concentration was rapidly increased after feeding and not significantly different in the urea treatment (13.53 mg/100 ml). Protozoa numbers were not significantly different for soy protein and casein treatment compared to urea treatments during incubation. The average concentration of total VFA (mMol) was not detected with significant difference among treatments, but iso-butyrate production showed the highest for soy protein treatment among treatments (p<0.001). The lowest concentration in total iso-acids (iso-butyrate and iso-valerate) production was observed in urea treatment. The soy protein treatment showed no significantly change in acetate/propionate. The amounts of dry matter (DM) out flow showed no significant difference among treatments. Organic matter (OM) flow was the highest for urea treatments and the lowest for casein treatment (p<0.03). The nitrogen flow for casein treatment was not significantly different from other treatments. The efficiency of microbial protein synthesis in terms of microbial nitrogen (MN) synthesis (g MN/kg ADOM) digested in the rumen was highest for casein treatment (58.53 g MN/kg ADOM) compared to soy protein and urea (p<0.05). This result suggests that rumen ammonia releasing rate may influence on microbial protein synthesis in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.685-691
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• 1998

In the first of two experiments, chemical composition (Ash, CP and CF contents), nutritive value (in vitro organic matter disappearance "lVOMD" and energy content "ME") and nitrogen retention of chopped date fronds (CDF) as affected by chemical treatment (CT) and storage duration (SD) were investigated. The experimental design was a completely randomized block, arranged in a $3{\times}4$ factorial, with 3 (CT) and 4 (SD) as the main factors using 2 replications / treatment. Three chemical treatments, were used : Control (With zero or no chemical treatment); treatment with 4% urea solution (w /w) and treatment with 4% urea + Date syrup extract (DS). The 4 (SD) were: Control (immediately after opening - without any storage or zero time storage); one month storage period; two months storage period and three months storage period. Both (CT) and (SD) had significant effects (p < 0.05) on CP and ash contents of the CDF, however there were no significant effects (p > 0.05) due to (CT) and (SD) on CF and nutritive value. High retention value (> 80%) for nitrogen was reported for the treated CDF, immediately after opening the incubated material (zero SD). However, nitrogen retention decreased with increasing (SD) to 67% after one month (SD) but tended to stay at a fairly constant level of 67% until 3 months of storage. In experiment 2, the feeding value of treated CDF was evaluated in comparison to Rhodes grass hay, using growing goats and sheep. A $4{\times}2$ factorial design was used (Four roughage sources were used : Rhodes grass hay, untreated CDF, urea-treated CDF and CDF treated with urea + DS with sheep and goats as two animal species, using three animals / treatment). Untreated CDF had a similar feeding value to Rhodes grass hay. However treatment of CDF with urea alone or with urea + DS depressed animal performance of both goats and sheep, apparently due to depression of feed intake (appetite). Feeding untreated CDF decreased feeding cost by 29% and cost/kg gain by 23%. CDF showed a good potential as a cheap local roughage and emergency feed for ruminants in the Sultanate.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.181-188
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• 2006

The objective of this research was to determine the effects of synchronizing the rate of dietary energy and nitrogen release on: ruminal fermentation, microbial protein synthesis, blood urea nitrogen, and nutrient digestibility in beef cattle. Four, two-and-a-half year old Brahman-Thai native crossbred steers were selected for the project. Each steer was fitted with a rumen cannula and proximal duodenal cannula. The steers were then randomly assigned in a $4{\times}4$ Latin square design to receive four dietary treatments. Prior to formulation of the dietary treatments, feed ingredients were analyzed for chemical composition and a nylon bag technique was used to analyze the treatments various ingredients for degradability. The treatments were organized in four levels of a synchrony index (0.39, 0.50, 0.62 and 0.74). The results showed that dry matter digestibility trend to be increased (p<0.06), organic matter and acid detergent fiber digestibility increased linearly (p<0.05), while crude protein and neutral detergent fiber digestibility were not significantly different (p>0.05). Higher concentration and fluctuation of ruminal ammonia and blood urea were observed in the animal that received the lower synchrony index diets. As the levels of the synchrony index increased, the concentrations of ruminal ammonia nitrogen and blood urea nitrogen, at the 4 h post feeding, decreased linearly (p<0.05). Total volatile fatty acid and bacteria populations at the 4 h post feeding increased linearly (p<0.05). Microbial protein synthesis trend to be increase (p<0.08). The results of this research indicate that synchronizing the rate of degradation of dietary energy and nitrogen release improves ruminal fermentation, microbial protein synthesis and feed utilization.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.224-228
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• 1973

In the fermentation for preparation of petroprotein by Rhodotorula sp. in $C_{12}{\sim}C_{14}$n-alkane mixture it was investigated how the effects due to the difference of chemical form of the nitrogen sources are, that is, how the inorganic nitrogen sources such as nitrates and ammonium salts and organic nitrogen source such as urea effect on the view of fermentation time and yield and how the ratios of nitrogen to carbon with $NaNo_3$ effect. Then following results were obtained: the time required to maximum growth, when $NaNo_3$ or $(NH_4)_2SO_4$ was used as nitrogen source, was 40 hrs. and 45 hrs., respectively, but when urea was used, it was 66 hrs. much longer than above nitrogen sources. On the view of yield, however, in use of the both inorganic sources, when the yield is represented as consumption of 0.1 N-NaOH, it was 0.36 and 0.38 ml, respectively, but, in the case of urea, it amounted to 0.78 ml. In the effect of the ratios of nitrogen to carbon in medium, when n-alkane mixture was added in 1 % (vol.) and N/C with $NaNo_3$ was 0.2 the best results were obtained and generally the higher the value of the ratio the better growth effects were shown.

• Journal of Climate Change Research
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• v.6 no.3
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• pp.249-256
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• 2015

This study was conducted to investigate the effects of different levels and types of nitrogen fertilizer on seedlings and soil chemical properties in a semi-arid area, Mongolia. 2-year-old Populus sibirica and 4-year-old Ulmus pumila seedlings were planted in May 2014. Six treatments with three levels of nitrogen (low-level: urea $5g\;tree^{-1}$; medium-level: urea $15g\;tree^{-1}$, ammonium sulfate $33g\;tree^{-1}$, urea $15g\;tree^{-1}$ with potassium phosphate $10g\;tree^{-1}$; high-level: urea $30g\;tree^{-1}$) were applied and for the medium-level of nitrogen, different types of fertilizer were treated. Survival rate, root collar diameter (RCD) growth rate, leaf nitrogen concentration of seedlings, and soil chemical properties were determined in August 2014. The seedling survival rate of both species decreased as the level of nitrogen increased. This result can be explained by water stress caused by nitrogen fertilization in arid regions. The RCD growth rate of P. sibirica was significantly decreased by the treatment of high-level of nitrogen due to excessive nitrogen fertilization, and was increased by the treatment of ammonium sulfate due to sulfur which might promote nitrogen uptake. The leaf nitrogen concentration of P. sibirica did not change by the treatment of low-level of nitrogen, and was increased by the treatment of medium-level of nitrogen. There were no significant differences in the RCD growth rate and the leaf nitrogen concentration of U. pumila among the six treatments. None of soil chemical properties was affected by nitrogen fertilization. Overall, the low-level of nitrogen showed no effect on seedlings and soil chemical properties, except on survival rate of U. pumila and the high-level of nitrogen was considered excessive fertilization. Continuous monitoring of medium-level nitrogen fertilization including the ammonium sulfate, which increased early growth of seedlings, would be needed to elucidate the effect of fertilization on seedling growth and soil properties in a semi-arid region.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.187-193
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• 2014

As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers ($213{\pm}4$ kg) were used in a $4{\times}4$ Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p<0.05). Ruminal digestion of OM, starch and feed N were not affected by urea combination or S:F ratio. The urea combination did not affect ADF ruminal digestion. ADF ruminal digestion decreased linearly (p = 0.02) as the S:F ratio increased. Compared to the urea treatment (p<0.05) and within the urea combination treatment (quadratic, p<0.01), the flow of microbial nitrogen (MN) to the small intestine and ruminal microbial efficiency were greater for the urea combination at a S:F ratio of 4.5. Irrespective of the S:F ratio, the urea combination improved (2.8%, p = 0.02) postruminal N digestion. As S:F ratio increased, OM digestion increased, but ADF total tract digestion decreased. The combination of urea at 4.5 S:F improved (2%, p = 0.04) the digestible energy (DE) more than expected. Combining urea and Optigen resulted in positive effects on the MN flow and DE of the diet, but apparently these advantages are observed only when there is a certain proportion of starch:ADF in the diet.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.151-155
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• 2000

Phaeodactylum tricornutum (Bacillariophyceae) is a marine diatom which has been supplied as a food of bivalves. In this study, growth responses of P. tricornutum to some nitrogen sources and sodium were investigated by measuring cell number and contents of chlorophyll a in culture. In medium with nitrogen and sodium, brisk cell division occurred and maximum growth rate was respectively found in the medium with 150 mg/l of nitrate and 10 mg/l of ammonium and urea. At 10-500 mg/l ammonium and urea and 200-500 mg/l nitrate, specific growth rate decreased slightly. However, no cell division observed in sodium-deficient medium, regardless of presence or absence of nitrogen. This suggests that sodium is required for the nitrogen uptake of P. tricornutum, resulting nitrogen uptake leading to cell division. Also the upper limits of ammonium and nitrate for the growth of P. tricornutum seem to be 10 mg/l and 500 mg/l, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.171-176
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• 1991

Field experiment was conducted to investigate the seasonal change in inorganic nitrogen content in grassland soil profile after urea application. Urea was applied at the levels of 0 (0N), 14 (14N), and 28 (28N) Kg N per 10a. Soil samples were taken at every 20 cm interval upto 100 cm soil depth in spring (May 26), summer (July 27), and autumn (October 18) and analysed for total and inorganic nitrogen ($NH_4-N$ and $NO_3-N$). The results obtained are as follows ; 1. In spring, the $NH_4-N$ content of ON treatment was higher than $NO_3-N$ content both in surface and subsoil. The urea application increasing both $NH_4-N$ and $NO_3-N$ contents in the surface soils and these contents decreased with soil depth. 2. In summer, increase in urea application rate elevated the $NO_3-N$ content in soil profile of 0 to 100cm and the content reached upto 42 ppm in the 28N treatment. 3. The seasonal difference in $NH_4-N$ content between summer and autumn was insignificant throughout soil profile. Soil $NO_3-N$ content in autumn were 7 and 14 ppm for 14N and 28N respectively, showing very low values compared with that of summer. 4. The ratio of inorganic nitrogen to total nitrogen increased with soil depth and with urea application rates.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.418-426
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• 2023

This study focused on nitrous oxide, a major greenhouse gas produced in agricultural settings through bacterial nitrogen oxidation in aerobic soil. Nitrogen fertilizer in farmland is identified as a primary source of nitrous oxide. The importance of reducing excess nitrogen in soil to mitigate nitrous oxide production is well-known. The study investigated the use of liquefied pig manure as an alternative to urea fertilizer in conventional agriculture. Results showed a more than two-fold reduction in nitrous oxide emissions in pepper cultivation areas with liquefied pig manure compared to that with urea fertilizer. The population of Nitrosospira, a nitrous oxide-producing bacterium, decreased by over 10% with liquefied pig manure. Additionally, nirK and nosZ, which are related to the denitrification process, significantly increased in the urea fertilizer group, whereas levels in the liquefied pig manure group resembled those with no nitrogen treatment. In conclusion, the experiment confirmed that liquefied pig manure can serve as an eco-friendly nitrogen fertilizer, significantly reducing nitrous oxide production, a major contributor to the atmospheric greenhouse effect.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.185-189
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• 1997

The objectives of this study were to relate concentrations of plasma urea nitrogen(PUN) to conception rate in dairy cows. the relationship between PUN concentration and time postcalving was examined for 11 individual cows. Mean concentration of PUN rose for serveral weeks after calving and then was stable from 7 week. As PUN increased, the rate of conception decreased. Cows with PUN<15 and 15∼19.9mg/dl had the likelihood ratios of conception of 1.33 and 1.67. As PUN increased 20∼22.9 and 23mg/dl, the likelihood ratios decreased to 1.00 and 0.90. Thus, low PUN had a favorable association with conception, whereas high PUN had a negative association with conception.