• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.315-322
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• 2016

This study determined the optimum microalgae species and concentration for growth of small rotifer Proales similis, in community cultures by feeding it several different foods. Four single trials (Tetraselmis suecica, TET; Isochrysis galbana, ISO; Nannochloropsis oculata, NAN; freshwater Chlorella vulgaris, CHL) were conducted at 5 psu and $25^{\circ}C$. The maximum density and specific growth rate (SRG) were highest for rotifer fed CHL reaching 1,075 individuals (inds.)/mL and 0.83 respectively. By contrast, other foods of ISO, NAN and TET resulted in poor growth rates and maximum density. In the freshwater C. vulgaris experiments examining a range of 0.05 to $8.8mg/10^4rotifers$, the growth of rotifer tended to decrease with the amount of supplement. The maximum density and SGR of females was highest at 910 inds./mL and 0.55 respectively, at $0.05mg/10^4rotifers$. These results suggest that the best microalgae species for the culture of P. similis is freshwater C. vulgaris and the optimum concentration is $0.05mg/10^4rotifers$.

• KSBB Journal
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• v.15 no.1
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• pp.14-21
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• 2000

In this study, algae cultivation using the photobioreactor has been applied to remove the nitrogen and phosphorus compounds in the wastewater of the livestock industry. The optimal ratio of nitrate and ortho-phosphate concentration was found for the enhancement of removal efficiency. To achieve the high density culture of algae, the photobioreactor consisted of optical fibers wes developed to get the sufficient light intensity. The light could be illuminated uniformly from light source to the entire reactor by the optical fibers. The structured kinetic model was proposed to describe the growth rate, consumption rate of nitrates and ortho-phosphates in algae culture. The self-organizing fuzzy logic controller incorporated with genetic algorithm was constructed to control the semi-continuous wastewater treatment system. The proposed fuzzy logic controller was applied to maintain the nitrated concentration at the given set-point with the control of wastewater feeding rate. The experimental results showed that the self-organizing fuzzy logic controller could keep the nitrate concentration and enhance algae growth.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.496-501
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• 1995

Experiments were carried out to find out the optimal condition of SCP produced by Cellulomonas sp. KL-6 and to evaluate nutritional value for the protein of this organism Intracellular- and extracellular proteins produced by this strain were estimated to be nearly maximum, $266\;{\mu}g/m{\ell}\;and\;37\;{\mu}g/m{\ell}$, in the medium containing 0.001% of thiamin after 5 days cultivation. When used rice straw as carbon source for the cell growth of this organism after crusing them by cutting mill, and treating them with 1.0% of NaOH and 10.0% of $NH_4OH\;at\;80^{\circ}C$ for 30 minutes and neutralizing continuatively them with 85% of $H_3PO_4$, SCP production rates were very increased to $1.63\;g/{\ell}$ (NaOH) and $1.47\;g/{\ell}$ (NH4OH), respectively than $0.5\;g/{\ell}$ produced in untreated rice straw. We compared their amino acids patterns with that of FAO provisional patterns. Amino acids content of strain KL-6 was excellents. However. when intended these cell mass to use in practical animal feeding test it would be advisable that destruction or lysis of cell wall should be done.

• Korean Journal of Organic Agriculture
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• v.28 no.4
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• pp.605-614
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• 2020

This study was conducted to investigate the effects of TMR on in vitro rumen fermentation and methane production of goat with different forage sources. The experiment was arranged 4×2 factorial design. The different forage sources were rice straw (RS), Italian rye grass (IR), timothy (TI) and alfalfa (AL), respectively. There were two different forage : concentrate ratios such as 20:80 (20) and 50:50 (50), respectively. Therefore, totally 8 treatments were used: 1) RS20, 2) RS50, 3) IR20, 4) IR50, 5) TI20, 6) TI50, 7) AL20, and 8) AL50, respectively. The rumen fluid of goat was collected from the slaughterhouse. For fermentation parameters, ruminal pH, total gas, methane, hydrogen, ammonia nitrogen, and volatile fatty acid were determined. The pH values were within an optimal range across all treatments. Total gas productions at TI20 and AL50 were significantly greater than others (p<0.05). Methane production was significantly lower in TI and AL compared with other treatments (p<0.05). The relatively high dietary NDF content in treatments showed significantly lower methane production (p<0.05). Significant alterations treatments were detected at ammonia nitrogen concentration according to the ratio of forage : concentrate (p<0.05). AL treatment showed greater total volatile fatty acid production compared with other treatments (p<0.05). Therefore, the present study suggests that both Timothy and Alfalfa could be recommendable forage sources for goat based on results with volatile fatty acid as an energy source and methane as an index for energy loss and environmental issues. Also, the 50:50 (forage : concentrate) ratio would prefer to 20:80.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.1-6
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• 2019

Ptecticus tenebriferwas incorporated to partially or totally replace the diets of juvenile white shrimp (Litopenaeus vannamei). Experimental groups of shrimp with an average initial body weight of $0.014{\pm}0.001g$ were fed each of the 5 diets formulated to include 0, 25, 50, 75, and 100% (C, T25, T50, T75, and T100, respectively) of Ptecticus tenebriferpowder substituted for commercial feed. After eight weeks of feeding trials, juvenile shrimp fed with diets T25 and T50 showed higher live weight gain ($2.298{\pm}0.405$ and $2.539{\pm}0.406$, respectively), and a better feed conversion ratio ($1.389{\pm}0.246$ and $1.536{\pm}0.246$, respectively) compared to those of shrimp fed a control diet. Survival rate was 98% in all experimental groups except for the T75 group ($66.67{\pm}57.73%$ survival). The levels of immune markers such as beta-glucan binding protein, prophenoloxidase, and crustin associated with the cellular and humoral immunity of shrimp were found to be higher in 25% and 50% commercial feed replacement groups. A reduction in total nitrogen, nitrite nitrogen, and ammonia levels was greater in T25 and T50 rather than in T75 and T100. These results clearly indicate that replacement of feed with 25 to 50% Ptecticus tenebriferpowder in juvenile white shrimp diet was optimal in promoting the growth performance of shrimp without any adverse effects.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.170-181
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• 2019

This study aimed to investigate the effects of temperature and retention time of the pressurized steam chamber on the ruminal fermentation characteristics and nutrient degradability of corn flakes in three Korean native Hanwoo cows and three Holstein cows implanted with a ruminal fistula. Corn kernels were categorized into 13 groups based on the chamber temperature (range, $100^{\circ}C-116^{\circ}C$) and retention time (range, 700-950 s). The pH value was lowest in T1 regardless of breed. Propionate concentration was the highest in T2 (p < 0.05). Total-volatile fatty acid (VFA) concentration was slightly but not significantly greater in T2 than in other conditions. Dry matter (p < 0.05), starch, and crude protein (p < 0.05) degradability were the highest in T1. At different incubation times and with different breeds, dry matter, starch, and crude protein degradability of corn flakes were the highest in T1. Thus, the present results indicate that the optimal temperature and retention time of the pressurized steam chamber should be $100^{\circ}C-105^{\circ}C$ and 700-720 s.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.265-272
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• 2021

A total of fourteen primiparous sows' (Landrace × Yorkshire) were used to determine the effects of two patterns of feed intake during early gestation on the growth performance and litter characteristics in sows. Daily feed intake from day 5 to 112 of gestation for parity 1 sows was 2.2 kg·d^-1 of feed offered with the exception of seven sows who were offered 3.2 kg·d^-1 from day 90 to 108 of gestation (TRT A) or 2.5 kg·d^-1 (d 5 - 60) and 2 kg·d^-1 (d 60 - 90) of feed with the exception of seven sows who were offered 3.5 kg·d^-1 from day 90 to 108 of gestation (TRT B). The different feed intake patterns in early gestation did not have a significant effect on body weight, backfat thickness, or body condition score during, before, and after farrowing (p > 0.05) respectively. However, initial to d 60, backfat thickness difference was significantly improved by TRT B patterns of feed intake during early gestation. In addition, during the overall experiment, average daily feed intake was significantly enhanced for sows in the dietary TRT B group feed intake pattern (p = 0.0001). The fecal score during day 90 was significantly reduced (p = 0.0132) in sows fed with TRT B feed intake pattern. Litter size, litter survival rate, and initial weight showed no significant differences with different feed efficiency of gestating sows. In summary, the results indicate that the 2.5 kg·d^-1 gestation intake pattern allowed gestating sows to obtain optimal performance.

• ALGAE
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• v.36 no.4
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• pp.263-283
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• 2021

To explore the ecophysiological characteristics of the kleptoplastidic dinoflagellate Shimiella gracilenta, we determined its spatiotemporal distribution in Korean coastal waters and growth and ingestion rates as a function of prey concentration. The abundance of S. gracilenta at 28 stations from 2015 to 2018 was measured using quantitative real-time polymerase chain reaction. Cells of S. gracilenta were detected at least once at all the stations and in each season, when temperature and salinity were 1.7-26.4℃ and 9.9-35.6, respectively. Moreover, among the 28 potential prey species tested, S. gracilenta SGJH1904 fed on diverse prey taxa. However, the highest abundance of S. gracilenta was only 3 cells mL^-1 during the study period. The threshold Teleaulax amphioxeia concentration for S. gracilenta growth was 5,618 cells mL^-1, which was much higher than the highest abundance of T. amphioxeia (667 cells mL^-1). Thus, T. amphioxeia was not likely to support the growth of S. gracilenta in the field during the study period. However, the maximum specific growth and ingestion rates of S. gracilenta on T. amphioxeia, the optimal prey species, were 1.36 d^-1 and 0.04 ng C predator^-1 d^-1, respectively. Thus, if the abundance of T. amphioxeia was much higher than 5,618 cells mL^-1, the abundance of S. gracilenta could be much higher than the highest abundance observed in this study. Eurythermal and euryhaline characteristics of S. gracilenta and its ability to feed on diverse prey species and conduct kleptoplastidy are likely to be responsible for its common spatiotemporal distribution.

• ALGAE
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• v.37 no.1
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• pp.49-62
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• 2022

Water temperature affects plankton survival and growth. The dinoflagellate Shimiella gracilenta survives using the plastids of ingested prey, indicating kleptoplastidy. However, studies on the effects of water temperature on kleptoplastidic dinoflagellates are lacking. We explored the growth and ingestion rates of S. gracilenta as a function of water temperature. Furthermore, using data on its spatiotemporal distribution in Korean coastal waters during 2015-2018, we predicted its distribution under elevated temperature conditions of +2, +4, and +6℃. Growth rates of S. gracilenta with and without Teleaulax amphioxeia prey as well as ingestion rates were significantly affected by water temperature. Growth rates of S. gracilenta with and without prey were positive or zero at 5-25℃ but were negative at ≥30℃. The maximum growth rate of S. gracilenta with T. amphioxeia was 0.85 d^-1, achieved at 25℃, and 0.21 d^-1 at 20℃ without prey. The ingestion rate of S. gracilenta on T. amphioxeia at 25℃ (0.05 ng C predator^-1 d^-1) was greater than that at 20℃ (0.04 ng C predator^-1 d^-1). Thus, feeding may shift the optimal temperature for the maximum growth rate of S. gracilenta from 20 to 25℃. In spring and winter, the distributions of S. gracilenta under elevated temperature conditions were predicted not to differ from those during 2015-2018. However, S. gracilenta was predicted not to survive at some additional stations under elevated temperature conditions of +2, +4, and +6℃ in summer or under elevated temperature conditions of +6℃ in autumn. Therefore, global warming may affect the distribution of S. gracilenta.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.957-963
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• 2021

The study aimed to investigate the effects of supplemented sodium butyrate on the in vitro rumen fermentation and growth performance of Hanwoo calves. In total, four treatments were employed according to the sodium butyrate levels: no addition (control), an addition of 0.1% (treatment 1), an addition of 0.3% (treatment 2), and an addition of 0.5% (treatment 3). After 48 hours of fermentation, the ruminal pH was found to be higher in T1 than in C. Total volatile fatty acids were significantly higher in T2 and T3 than in C. The ratio of acetate and propionate was significantly lower in T1 and T3 than in C. In this study, the optimal concentration to promote rumen fermentation was found to be 0.3%, i.e., T2, and an experiment on Hanwoo calves at a farm was conducted. However, there were no significant differences between the treatment groups in terms of the daily weight gain, feed conversion ratio, and final body weight in the feeding experiment. Also, there were no significant differences in the body length, withers height, and height at hip cross between the control and the treatment groups. The addition of 0.3% sodium butyrate was most effective at promoting in vitro rumen fermentation, but it did not significantly affect the growth performance when fed to Hanwoo calves. This indicates that the addition of sodium butyrate improved rumen fermentation but did not have a growth-promoting effect. Future studies need to compare growth and carcass performance outcomes to confirm long-term effects.