• Asian-Australasian Journal of Animal Sciences
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• 제30권3호
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• pp.386-391
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• 2017

Objective: Protein supplementation is costly and can result in excess nitrogen (N) excretion. The objective of this study was to evaluate the effects of feeding different levels of dietary protein on average daily gain, body size, rumen fermentation, and nitrogen excretion of 8 to 10 month-old Holstein heifers. Methods: Thirty-six Holstein heifers were divided into 12 blocks according to age ($273{\pm}6.2d$) and were randomly assigned to diets containing a low (10.2% dry matter [DM]), medium (11.9% DM), or high (13.5% DM) level of dietary crude protein (CP). All diets contained approximately 70% roughage and 30% concentrate with similar dietary metabolizable energy (ME) content (2.47 Mcal/kg). Results: Dry matter intake did not differ among the treatments, and average daily gain increased with the increasing dietary protein, 0.79, 0.95, 0.97 kg/d for low, medium, and high group, respectively. Body height increased linearly with increasing dietary CP but no other significant differences in body dimensions were found among the treatments. The increased ratios of dietary CP improved the rate of rear teat length growth remarkably (p<0.05). There was no difference in rumen pH or ruminal major volatile fatty acid (acetate, propionate, and butyrate) concentration among the 3 diets, but rumen ammonia-N concentration increased with the higher dietary CP (p<0.05). Increasing N intake led to increased total N excretion; urinary N excretion was significantly increased (p<0.05) but fecal N excretion was similar among the treatments. Conclusion: These data suggest that the diet containing 11.9% CP (ME 2.47 Mcal/kg) could meet the maintenance and growth requirements of 9 to 11 month-old Holstein heifers gaining approximately 0.9 kg/d.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.9-12
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• 2005

본 연구에서는 셀룰로오즈 유도체로 사용되어지는 cellulose acetate butyate (CAB), cellulose acetate propionate (CAP), nitrocellilose (GC-519)의 분자량에 의한 유변학적 특성의 영향을 분석하기 위하여 각각의 셀룰로오즈 유도체를 Gel Permeartion Chromatography (GPC)를 이용하여 각각의 분자량을 측정하였다. GPC를 이용하여 셀룰로오즈 유도체의 중량평균분자량 (Mw)과 수평균분자량 (Mn)을 측정하였다. 각각의 셀룰로오즈 유도체에 가소제인 di-n-propyl adipate (DNPA)를 첨가한 뒤 아세톤에 녹여 레오미터를 이용하여 $0^{\circ}C$에서 가소제가 포함된 셀룰로오즈 유도체의 유변학적 특성을 측정하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권5호
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• pp.630-637
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• 2013

To determine the effects of dry period (DP) length on milk yield, milk composition, some blood metabolites, complete blood count (CBC), body weight and score and follicular status, twenty five primiparous and multiparous Holstein cows were assigned to a completely randomized design with DP-60 (n = 13) and DP-20 (n = 12) dry period lengths. Cows in the DP-60 produced more milk, protein, SNF, serum non-esterified fatty acids (NEFA) and beta hydroxyl butyrate acid (BHBA) compared with cows in DP-20 ($p{\leq}0.05$). Serum glucose, blood urea nitrogen (BUN), urea, and glutamic oxaloacetic transaminase (GOT) were all similar among the treatments. Body Condition Score (BCS), body weight (BW), complete blood count (CBC) and health problems were similar between the treatments. Diameter of the first dominant follicle and diameter of the dominant follicle on d 14 were different among the treatments. Thus, results of this study showed that reducing the dry period length to DP-20 had a negative effect on milk production, milk composition and reproductive performance in Holstein dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.700-707
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• 2010

Effects of protease-resistant antimicrobial substances (PRA) produced by Lactobacillus plantarum and Leuconostoc citreum on rumen methanogenesis were examined using the in vitro continuous methane quantification system. Four different strains of lactic acid bacteria, i) Lactococcus lactis ATCC19435 (Control, non-antibacterial substances), ii) Lactococcus lactis NCIMB702054 (Nisin-Z), iii) Lactobacillus plantarum TUA1490L (PRA-1), and iv) Leuconostoc citreum JCM9698 (PRA-2) were individually cultured in GYEKP medium. An 80 ml aliquot of each supernatant was inoculated into phosphate-buffered rumen fluid. PRA-1 remarkably decreased cumulative methane production, though propionate, butyrate and ammonia N decreased. For PRA-2, there were no effects on $CH_4$ and $CO_2$ production and fermentation characteristics in mixed rumen cultures. The results suggested that PRA-1 reduced the number of methanogens or inhibited utilization of hydrogen in rumen fermentation.

• 한국환경보건학회지
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• 제31권4호
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• pp.294-300
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• 2005

Food waste can be a valuable carbon source in biological nutrient removal (BNR) systems because of high C/N and C/P ratios. However, food waste should be pretreated to promote its hydrolysis rate because hydrolysis reaction would be a rate-limiting step. This study investigates the influence of the enzymatic pretreatment on acid fermentation of food waste. Solubilization of particulate matter in food waste by using commercial enzymes was examined. The acidification efficiency and the volatile fatty acids (VFAs) production potential of enzymatically pretreated food waste were also examined. The highest volatile suspended solids (VSS) reduction was obtained with an enzyme mixture ratio of 1:2:1 of carbohydrase:protease:lipase. An optimum enzyme dosage for solubilization of food waste was $0.1\%$(V/V) with the enzyme mixture ratio of 1:2:1. In the acid fermentation of enzymatically pretreated food waste, $0.1\%$(V/V) enzyme mixture dosage for pretreatment result in the maximum VFAs production and the best VFAs fraction in soluble COD(SCOD). The VFAs production at this addition level was 3.3 times higher than that of no-enzyme added fermenter. The dominant VFAs present was n-butyrate followed by acetate.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.283-291
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• 2019

Fermentation of food waste in the presence of different concentrations of salt ($Na^+$) and ammonia was conducted to investigate the interrelation of $Na^+$ and ammonia content in bio-hydrogen production. Analysis of the experimental results showed that peak hydrogen production differed according to the ammonia and $Na^+$ concentration. The peak hydrogen production levels achieved were (97.60, 91.94, and 49.31) ml/g COD at (291.41, 768.75, and 1,037.89) mg-N/L of ammonia and (600, 1,000, and 4,000) $mg-Na^+/L$ of salt concentration, respectively. At peak hydrogen production, the ammonia concentration increased along with increasing salt concentration in the medium. This means that for peak hydrogen production, the C/N ratio decreased with increasing salt content in the medium. The butyrate/acetate (B/A) ratio was higher in proportion to the bio-hydrogen production (r-square: 0.71, p-value: 0.0006). Different concentrations of $Na^+$ and ammonia in the medium also produced diverse microbial communities. Klebsiella sp., Enterobacter sp., and Clostridium sp. were predominant with high bio-hydrogen production, while Lactococcus sp. was found with low bio-hydrogen production.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.432-439
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• 2020

이 연구는 급여하는 조사료와 농후사료 비율을 달리하였을 때, 우분 내 대사체 비교를 핵자기공명장치로 확인하기 위해 실시되었다. 착유중인 젖소 6마리를 두 그룹으로 나누어 조사료와 농후사료 급여 비율(HR 그룹=8:2, HC 그룹=2:8)을 달리 하였다. 우분은 직장을 통해 마리별 1회 채취 하였으며 대사체 분석은 SPE-800 MHz NMR-MS system을 이용하였다. 대사체의 정성 및 정량은 Chenomx NMR suite 8.4을 이용하였으며, 확인된 대사체들을 Metaboanalyst 4.0을 이용하여 다변량 분석, 대사경로 분석을 진행하였다. 통계분석은 SAS program을 이용하여 Dunnett's test로 그룹 간 대사체 평균값을 비교 하였다. 분석 결과, 다변량 분석에서는 그룹간의 분리가 확인 되었으며 확인된 대사체 중 통계분석에는 77개의 대사체가 이용되었다. HC 그룹에서 유의적으로 높았던 대사체는 succinate를 포함한 dimethylamine, histamine, homovanillate, thymol, acetate, propionate, butyrate, isovalerate, valerate, imidazole, N-Nitrosodimethylamine 그리고 O-Acetylcholine 이다. HC 그룹에서 분석된 대사체들의 평균 농도가 HR 그룹에 비해 높았으며, 분석된 대사경로 또한 HR 그룹에 비해 다양했다. 연구결과, 핵자기공명분광장치를 통해 분석한 우분 내 대사체는 장내 미생물 뿐 만 아니라 체내 대사 그리고 향후 축산 관련 다양한 연구에 유용하게 사용될 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.852-862
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• 2003

An experiment was conducted to study the effect of ionophore enriched cold processed mineral block supplemented with urea molasses on microbial growth and rumen fermentation. Twelve adult male crossbred cattle were divided into four groups on body weight basis. Animals were given wheat straw as a basal diet. The animals of group I and II were supplemented with concentrate mixture and animals of group III and IV were supplemented with cold processed urea molasses mineral block (UMMB). Thirty mg monensin/day/animal were supplemented to the animals of group II and 35 ppm monensin were incorporated in the UMMB supplemented to the animals of group IV. Dry matter (DM) intake did not differ significantly among groups. Mean rumen pH was higher in UMMB fed animals. Total volatile fatty acids (TVFA) concentration (mmole/L strained rumen liquor (SRL) in group III (113.19) was significantly (p<0.05) higher than those of group I (105.83) and II (108.74) but similar to group IV (109.34). TVFA production (mole/day) was similar in all the groups. The molar proportion of acetate was significantly (p<0.01) higher in the group I (59.56) than those of group II (51.73) and IV (55.91) but similar to group III (57.12). The molar proportion of propionate was significantly (p<0.01) higher in the monensin treated groups i.e. group II (38.38) and IV (36.26) than those of group I (27.78) and III (33.06). Butyrate molar percent was significantly (p<0.01) higher in group I (12.65) than those of group II (10.19), group III (9.83) and IV (7.84). The reduction of acetate and butyrate was due to UMMB and monensin resulted in lower A:P ratio. Average bacterial pool and bacterial production rate did not differ significantly among groups. Total N concentration (mg/100 ml SRL) was significantly (p<0.01) higher in the group I (55.30) and III (57.70) as compared to the group II (47.97) and IV (47.59). Ammonia-N concentration (mg/100 ml SRL) of group III (34.99) was significantly (p<0.01) higher than that of the group I (25.76) which was again significantly (p<0.01) higher than that of the group II (20.79) and IV (19.83) indicating slower release of ammonia due to monensin in diet. Total bacterial, cellulolytic, proteolytic bacterial and fungal count at 4 h post feeding did not differ significantly (p<0.05) among treatment groups. However, methanogenic bacterial count was significantly (p<0.01) higher in the group I (11.80) compared to the group II (8.43) which was significantly (p<0.01) higher than that of the group III (4.70) and IV (2.90). Average protozoal population was affected by both treatments. Thus feeding of UMMB and monensin in diet affected the rumen fermentation pattern towards propionate production, slower release of ammonia and reduction in methanogenic bacteria in the rumen.

• KSBB Journal
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• 제20권6호
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• pp.425-430
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• 2005

1. $H_2$ 생산속도와 $H_2$ 수율의 안정화를 근거로 판단컨대 start-up 기간은 30일 이내로 나타나 중온 CSTR에 비해 짧은 편이었다. 2. 고온 CSTR의 최고 $H_2$ 수율은 2.4 mol $H_2/mol$ glucose로 나타나 보고 된 중온의 것에 비해 우수한 편에 속하였다. 3. 운전 초기에 $CH_4$이 발생하였으나 14일 이후부터는 pH를 5.0 이하로 유지하면 거의 검출되지 않는 것으로 봐서 메탄생성균이 식종균에 남아 있더라도 반응기 운전 조건을 통해 $CH_4$ 발생을 억제할 수 있었다. 4. 고온 CSTR은 초기 운전 후에 적용한 운전조건의 변화(유입 포도당 농도, pH, 및 온도)에 민감한 것으로 나타났다. 특히 pH 및 온도변화에 대해 $H_2$ 생산속도와 $H_2$ 수율, 포도당 제거율 면에서 반응기 성능의 감소 및 불안정이 나타나, 운전 조건 변화 후에 나타난 고온 CSTR의 성능회복이 쉽지 않음을 알 수 있었다. 5. 문헌에 보고 된 중온 CSTR과는 달리 고온 CSTR는 일정한 조건에서도 불안정 한 성능을 나타내기도 하였다. 6. 불안정한 반응기 성능은 lactate 농도 증가와 더불어 n-butyrate와 acetate 농도 감소를 동반하였다. 생산된 n-butyrate와 acetate의 농도는 lactate의 농도변화와 반대의 경향을 나타내었다. 7. 비교적 긴 HRT와 침전조를 이용한 biomass의 재순환에도 불구하고, 유입 포도당의 농도가 낮아 biomass 농도는 다른 중온 반응기에서 보고된 것에 비해 낮은 편이었다. 8. T. thermosaccharolyticum와 계통발생학적으로 관련된 개체군이 반응기 운전 후 약 40일부터 우점으로 나타나 반응기 성능과 상관없이 그 이후로 계속 우세한 것으로 나타났다.

• 유기물자원화
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• 제11권1호
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• pp.70-76
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• 2003

소화슬러지를 열처리한 혼합 배양 미생물을 식종균으로, 자당을 기질로 사용하는 혐기성 수소 생산 공정을 운전하면서 pH 조절, 반복 열처리, 기질 농도 변화 등을 통해 지속적인 수소 생산 방법을 고찰하였다. 유입 기질의 농도가 5g COD/L인 경우 운전 초기에는 $0.5mole\;H_2/mole\;hexose$ 이상의 수소가 발생하지만 9일 이상 지속되지 못하였다. 이러한 현상의 원인은 수소 생성균이 공정 내에서 고농도로 존재하지 못하기 때문인 것으로 판단되며 pH를 5.3으로 유지하는 것만으로는 극복될 수 없었다. 반복 열처리를 적용할 경우 별도의 식종균 재주입 없이 효율이 감소된 수소 생성 공정을 원상태로 복구할 수 있음을 확인할 수 있었으나, 수소 생성 효율이 시간에 따라 감소하므로 열처리를 자주 해야 하는 문제가 발생했다. 유입 기질의 농도가 30g COD/L인 경우에는 24일간 지속적인 수소 생성이 가능하였으며, CSTR의 경우 $1.0-1.4mole\;H_2/mole\;hexose$, ASBR의 경우에는 $0.2-0.3mole\;H_2/mole\;hexose$의 생성 효율을 보였다. 수소 생성 시 유출수 내 용존성 유기물의 90% 이상은 유기산이었으며 그 중 n-butyrate가 가장 많은 양을 차지하였다.