• Proceedings of the Korean Society of Crop Science Conference
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• 2003.05a
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• pp.38-38
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• 2003

• Proceedings of the Korean Society of Grassland Science Conference
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• 2005.06a
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• pp.160-161
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• 2005

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.68-72
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• 2004

The effects of the addition of yeast on in vitro roughage degradability and methane production were investigated in order to clarify the effects of yeast on the rumen microbes and to establish methods of rumen manipulation. Three roughages (whole crop corn, rice straw and Italian ryegrass) were incubated for 3, 6, 12 and 24 h with or without dried beer yeast following the method described by Tilley and Terry. Using the same method, these roughages were incubated with or without yeast extract, albumin or purified DNA. In vitro methane production was measured with or without dried beer yeast at 12 and 24 h. The degradability of yeast was found to be 57 and 80% at 12 and 24 h, respectively. The rate of degradation of fraction b was 6.16%/h. There was a significant increase in roughage degradability at 6 h (p<0.05), 12 h (p<0.05) and 24 h (p<0.01) by dried yeast addition. The degradability of all three roughages was higher in the samples treated with yeast extract than in the no addition samples except in the case of rice straw incubated for 12 h. Nevertheless, the magnitude of increment was smaller with the addition of yeast extract than without the addition of yeast. With the addition of purified DNA, there were significant increases in roughage degradability at 6 h (p<0.01), 12 h (p<0.01) and 24 h (p<0.05); however, higher degradability values were detected in the samples to which albumin was added, particularly at 6 h. If the degradability values of the no addition samples with those of samples containing yeast, yeast extract, DNA and albumin were compared, the largest difference was found in the samples to which yeast was added, although it is worth noting that higher values were observed in the yeast extract samples than in the DNA or albumin samples, with the exception of the case of rice straw incubated for 24 h. Methane production was significantly increased at both 12 and 24 h incubation. The increment of roughage degradation and methane production brought about by the addition of dried beer yeast to the samples was thought to be due to the activation of rumen microbes. Water soluble fraction of yeast also seemed to play a role in ruminal microbe activation. The increment of degradability is thought to be partially due to the addition of crude protein or nucleic acid but it is expected that other factors play a greater role. And those factors may responsible for the different effects of individual yeast on ruminal microbes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.339-346
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• 2008

The contents of starch, moisture, crude protein, crude fat, crude fiber, and ash of different varieties of various crops such as brown rice, barley, corn, sweet potato were analyzed. The average starch contents of brown rice, barley, corn, and sweet potato were $70.1{\pm}0.4\;{\sim}\;72.2{\pm}2.1$, $68.7{\pm}0.2\;{\sim}\;71.4{\pm}1.2$, $67.6{\pm}0.8\;{\sim}\;69.4{\pm}1.8$, and $21.7{\pm}0.9\;{\sim}\;28.3{\pm}0.5%$, respectively. The ground powder of each starchy substrate was suspended in distilled water, and then liquefied, saccharified, and fermented by dried active yeast at 32 for 4 days. By statistical analysis, the effectiveness of the contents of the different components such as starch, moisture, crude protein, crude fat, crude fiber, and ash of the crops on the ethanol production were examined. The results showed that the starch content positively affected the ethanol production in all the tested cereals and sweet potato. In brown rice, ash content affected negatively the ethanol production. In barley, protein content affected negatively the ethanol production, while fiber content affected positively the ethanol production. The sweet potato containing higher content of moisture produced less amount of ethanol.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.328-332
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• 2014

For mass production of entomopathogenic fungus Beauveria bassiana 149, isolated from moth larva, by two-phase fermentation, we performed selection of carbon and nitrogen sources for liquid culture and examined solid fermentation on carrier, ingredient, temperature, and water content. Spore production with rice powder, corn powder, and starch from sweet potato was higher than that of sucrose and dissolvable starch for liquid fermentation as first-phase fermentation. As a nitrogen source, addition of peptone and yeast powder showed higher spore production than $NaNO_3$, fish powder, and soybean powder. The isolate produced more conidia in sawdust + wheat bran + corn powder, sawdust + wheat bran and rice shell + wheat bran as carrier and ingredient than vermiculite as carrier. Conidia production of B. bassiana 149 in solid-phase fermentation was twice higher at 30 than 20. Conidia yield was higher at 60% and 70% water content ($26.9{\times}10^8$ and $38.6{\times}10^8conidia/g$) than 40% and 50% ($13.9{times}10^8 $and $11.6{\times}10^8conidia/g$), respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.75-79
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• 2005

There were three trials involved in this experiment. All piglets in Trial 1 were randomly distributed into the following 4 treatments. Treatment 1. Corn-soybean diet with 5% SDPP. The tryptophan level was 0.237%. Treatment 2. Corn-soybean diet with 10% meat and bone meal. The tryptophan level was 0.177%. Treatment 3. Treatment 1+0.0662% synthetic tryptophan. The total tryptophan level was 0.303. Treatment 4. Treatment 2+0.0662% synthetic tryptophan. The total tryptophan level was 0.236. Piglets in Trial 2 were distributed randomly into the following 4 treatments. Treatment 1: corn-soybean diet+10% meat and bone meal. The total tryptophan level was 0.176%. Treatment 2: corn-soybean diet+10% meat and bone meal+5% SDPP. The total tryptophan level was 0.180%. Treatment 3: Treatment 1 diet+0.004% synthetic tryptophan. The total tryptophan level was 0.180%. Treatment 4: Treatment 1 diet+0.631% synthetic tryptophan. The total tryptophan level was 0.237%. There were 4 treatments in Trial 3. Treatment 1: cornsoybean diet+10% meat and bone meal. The total tryptophan level was 0.176%. Treatment 2: Treatment 1 diet+0.061% synthetic tryptophan. The total tryptophan level was 0.237%. Treatment 3: Treatment 2 diet+0.061% synthetic tryptophan. The total tryptophan level was 0.298%. Treatment 4: corn-soybean diet+10% meat and bone meal+5% SDPP. The total tryptophan level was 0.180%. The results of Trial 1 showed that the piglets ate significantly more (p<0.05) when feed included SDPP in the diet during the first 2 weeks. The feed intake also increased when synthetic tryptophan was added in the 5% meat and bone meal diet; however, the difference did not reach a significant level (p>0.05) during the first 2 weeks. Three weeks onwards the feed intake of 5% meat and bone meal treatment was significantly lower (p<0.05) than for the other three treatments. The results of Trial 2 showed that the feed intake could be significantly improved only when the total tryptophan level reached 0.237%. Piglets in the 5% SDPP treatment had higher feed intake than piglets in 10% meat and bone meal treatment with 0.180% of tryptophan, but did not reach a significant level (p<0.05). Body weight gain also had the same trend as feed intake. The pigs in Treatment 1, the lowest total level of tryptophan treatment (0.176%), had lowest feed intake and weight gain, but the difference did not reach a significant level (p>0.05). The pigs in Treatment 1 of Trial 3 had the lowest feed intake and weight gain (p>0.05). Treatment 2 (0.237%) had the highest average feed intake from Week 1 to Week 5; the second best result was recorded in Treatment 4. As for the weight gain of the piglets in Treatment 4 (5% SDPP), they had a higher average weight during the first 3 weeks. The feed efficiency was better for Treatment 4 (5% SDPP) during the first 2 weeks. The results of these trials showed that both SDPP and tryptophan had a trend to improve the feed intake and weight gain.

• Journal of Biosystems Engineering
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• v.30 no.1 s.108
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• pp.45-55
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• 2005

Knowledge of the relationship between crop yield and yield-limiting factors is essential for precision farming. However, developing this knowledge is not easy because these yield-limiting factors are interrelated and affect crop yield in different ways. In this study, data for grain yield and yield-limiting factors, including crop chlorophyll content, soil chemical properties, and topography were collected for a small (0.3 ha) rice paddy field in Korea and a large (36 ha) upland corn field in the USA, and relationships were investigated with path analysis. Using this approach, the effects of limiting factors on crop yield could be separated into direct effects and indirect effects acting through other factors. Path analysis provided more insight into these complex relationships than did simple correlation or multiple linear regression analysis. Results of correlation analysis for the rice paddy field showed that EC, Ca, and $SiO_2$ had significant (P<0.1) correlations with rice yield, while pH, Ca, Mg, Na, $SiO_2,\;and\;P_2O_5$ had significant correlations with the SPAD chlorophyll reading. Path analysis provided additional information about the importance and contribution paths of soil variables to rice yield and growth. Ca had the highest direct effect (0.52) and indirect effect via Mg (-0.37) on rice yield. The indirect effect of Mg through Ca (0.51) was higher than the direct effect (-0.38). Path analysis also enabled more appropriate selection of important factors limiting crop yield by considering cause-and-effect relationships among predictor and response variables. For example, although pH showed a positive correlation (r=0.35) with SPAD readings, the correlation was mainly due to the indirect positive effects acting through Mg and $SiO_2$, while pH not only showed negative direct effects, but also negatively impacted indirect effects of other variables on SPAD readings. For the large upland Missouri corn field, two topographic factors, elevation and slope, had significant (P<0.1) direct effects on yield and highly significant (P<0.01) correlations with other limiting factors. Based on the correlation analysis alone, P and K were determined to be nutrients that would increase corn yield for this field. With the help of path analysis, however, increases in Mg could also be expected to increase corn yield in this case. In general, path analysis results were consistent with published optimum ranges of nutrients for rice and com production. We conclude that path analysis can be a useful tool to investigate interrelationships between crop yield and yield limiting factors on a site-specific basis.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.77-82
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• 2014

The study aimed to evaluate the potential effects of feeding with phytase transgenic corn (PTC) on organ weight, serum biochemical parameters and nutrient digestibility, and to determine the fate of the transgenic DNA in laying hens. A total of 144 50-week-old laying hens were grouped randomly into 2 treatments, with 8 replicates per treatment and 9 hens per replicate. Each treatment group of hens was fed with diets containing 62.4% non-transgenic conventional corn (CC) or PTC for 16 weeks. The phytase activity for CC was 37 FTU/kg of DM, whereas the phytase activity for PTC was 8,980 FTU/kg of DM. We observed that feeding PTC to laying hens had no adverse effect on organ weight or serum biochemical parameters (p>0.05). A fragment of a poultry-specific ovalbumin gene (ov) was amplified from all tissues of hens showing that the DNA preparations were amenable to PCR amplification. Neither the corn-specific invertase gene (ivr) nor the transgenic phyA2 gene was detected in the breast muscle, leg muscle, ovary, oviduct and eggs. The digestibility data revealed no significant differences between the hens that received the CC- and PTC-based diets in the digestibility of DM, energy, nitrogen and calcium (p>0.05). Phosphorus digestibility of hens fed the PTC-based diet was greater than that of hens fed the CC-based diet (58.03% vs 47.42%, p<0.01). Based on these results, it was concluded that the PTC had no deleterious effects on the organ weight or serum biochemical parameters of the laying hens. No recombinant phyA2 gene was detected in muscle tissues and reproductive organs of laying hens. The novel plant phytase was efficacious in improving the phosphorus digestibility of laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.10
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• pp.1454-1464
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• 2015

Four methods were adopted, including the mobile nylon bag (MNB) method, modified three-step in vitro (MTS) method, original three-step in vitro (OTS) method, and acid detergent insoluble nitrogen (ADIN) estimating method, to evaluate the intestinal digestibility of rumen undegradable protein (DRUP) of 10 types of concentrates and 7 types of roughages. After correlation analysis to determine the DRUP values using the MNB, MTS, OTS, and ADIN methods, the study aimed to find out appropriate methods to replace the MNB method due to its disadvantages such as high price, long time period, and use of a duodenal T-fistula. Three dairy cows with a permanent ruminal fistula and duodenal T-fistula were used in a single-factor experimental design. The results showed that the determined DRUP values using the MNB method for soybean meal, cottonseed meal, rapeseed meal, sunflower meal, corn germ meal, corn, rice bran, barley, wheat bran, corn fiber feed, Alfalfa (Zhao dong), Alfalfa (Long mu 801), Alfalfa (Long mu 803), grass (North), Grass (Inner Mongolia), corn silage and corn straw were 98.13%, 87.37%, 88.47%, 82.60%, 75.40%, 93.23%, 69.27%, 91.27%, 72.37%, 79.03%, 66.72%, 68.64%, 73.57%, 50.47%, 51.52%, 54.05%, and 43.84%, respectively. The coefficient of determination ($R^2=0.964$) of the results between the MTS method and the MNB method was higher than that ($R^2=0.942$) between the OTS method and the MNB method. The coefficient of determination of the DRUP values of the concentrates among the in vitro method (including the MTS and OTS methods) and the MNB method was higher than that of the roughage. There was a weak correlation between the determined DRUP values in concentrates obtained from the ADIN method and those from the MNB method, and there was a significant correlation (p<0.01) between the determined DRUP values of the roughage obtained from the MNB method and those obtained from ADIN method. The DRUP values were significantly correlated with the nutritional ingredients of the feeds. The regression equation was DRUP =100.5566+0.4169CP - 0.4344SP - 0.7102NDF - 0.7950EE ($R^2=0.8668$, p<0.01; CP, crude protein; SP, soluble protein; NDF, neutral detergent fiber; EE, ether extract). It was concluded that both the MTS method and the OTS may suitable to replace the MNB method for determining the DRUP values and the former method was more effective. Only the ADIN method could be used to predict the values of the roughages but conventional nutritional ingredients were available for all of the samples' DRUP.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1150-1159
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• 2017

Objective: This study was conducted to evaluate various wheat supplementation levels on growth performance, blood profiles, nutrient digestibility, and pork quality in growing-finishing pigs. Methods: A total of 120 growing pigs ($[Yorkshire{\times}Landrace]{\times}Duroc$), with an average $27.75{\pm}1.319kg$ body weight, were used in growth trial. Pigs were allotted into each treatment by body weight and sex in 4 replicates with 6 pigs per pen in a randomized complete block design. Fourphase feeding programs were used in this experiment. The treatments included the following: i) corn-soybean meal (SBM) - based diet (CON), ii) corn-SBM - based diet+15% of wheat (W15), iii) corn-SBM - based diet+30% of wheat (W30), iv) corn-SBM - based diet+45% of wheat (W45), and 5) corn-SBM-based diet+60% of wheat (W60). Results: There was no significant difference in growth performance among the dietary treatments. However, the gain-to-feed (G:F) ratio tended to increase (quadratic, p<0.08) when the pigs were fed a higher wheat diet during the finishing period. The digestibility of crude ash and fat tended to decrease as the wheat supplementation level increased (p<0.08). The proximate analysis of the longissimus muscle was not affected by the dietary level of wheat. The crude ash content in pork was decreased linearly as the wheat supplementation level increased (p = 0.05). There was no significant difference in the pH level, shear force, water holding capacity, and cooking loss of the pork. In pork and fat, $L^{\star}$, $a^{\star}$, and $b^{\star}$ values were not significantly different among dietary treatments. Conclusion: Wheat can be supplemented up to 60% in a growing-finishing pig without detrimental effects on growth and pork quality. The G:F ratio tended to improve in the finishing period by wheat inclusion.