• Asian-Australasian Journal of Animal Sciences
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• 제9권3호
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• pp.287-294
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• 1996

The objective of this study was to investigate the optimum level of the rumen protected lysine (RPLys) for early lactating Holstein dairy cow. This experiment was carried out with 16 Holstein dairy cows for 106 days and consisted of 4 treatments : $T_1$ (RPLys 0%), $T_2$ (RPLys 0.1%), $T_3$ (RPLys 0.2%) and $T_4$ (RPLys 0.3%). The results obtained are summarized as follows : 1. The daily intakes of feed were similar among treatments, but the digestibility of crude protein tended to increase 0.5-5.0% with increased level of RPLys and also the crude fiber digestibility increased (p < 0.05). 2. The daily weight gain for cows in $T_1$ was 253 g, which was lower than any other treatments (p < 0.05). The highest was 521 g in $T_3$. Also, the body condition score was changed from 3.22 at initial to 3.45 at final. The lowest increase in body condition score as 0.09 was obtained in control and the highest as 0.60 in $T_3$ (p < 0.01). 3. The total milk production of groups $T_2$, $T_3$ and $T_4$ were higher than $T_1$, as well as total protein, total fat and total solid yield. Especially in $T_4$ treatment group milk yield was higher than other treatments. The content of fat was higher in $T_2$ and $T_4$ compared to other treatments. Other components of milk were not significantly different (p > 0.05). The persistencies of lactation were increased in all RPLys treatments, especially, rate of reduction in milk yield was lowest in $T_4$ (p < 0.05). 4. The total amino acid content in the plasma, as well as plasma lysine content showed no consistent trend with treatments.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1126-1141
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• 2021

Recent evidence has shown that methionine (Met) supplementation can improve milk protein synthesis under hyperthermia (which reduces milk production). To explore the mechanism by which milk protein synthesis is affected by Met supplementation under hyperthermia, mammary alveolar (MAC-T) cells were incubated at a hyperthermic temperature of 42℃ for 6 h in media with different concentrations of Met. While the control group (CON) contained a normal amino acid concentration profile (60 ㎍/mL of Met), the three treatment groups were supplemented with Met at concentrations of 10 ㎍/mL (MET70, 70 ㎍/mL of Met), 20 ㎍/mL (MET80, 80 ㎍/mL of Met), and 30 ㎍/mL (MET90,90 ㎍/mL of Met). Our results show that additional Met supplementation increases the mRNA and protein levels of BCL2 (B-cell lymphoma-2, an anti-apoptosis agent), and decreases the mRNA and protein levels of BAX (Bcl-2-associated X protein, a pro-apoptosis agent), especially at an additional supplementary concentration of 20 ㎍/mL (group Met80). Supplementation with higher concentrations of Met decreased the mRNA levels of Caspase-3 and Caspase-9, and increased protein levels of heat shock protein (HSP70). The total protein levels of the mechanistic target of rapamycin (mTOR) and the mTOR signalling pathway-related proteins, AKT, ribosomal protein S6 kinase B1 (RPS6KB1), and ribosomal protein S6 (RPS6), increased with increasing Met supplementation, and peaked at 80 ㎍/mL Met (group Met80). In addition, we also found that additional Met supplementation upregulated the gene expression of αS1-casein (CSN1S1), β-casein (CSN2), and the amino acid transporter genes SLC38A2, SLC38A3 which are known to be mTOR targets. Additional Met supplementation, however, had no effect on the gene expression of κ-casein (CSN3) and solute carrier family 34 member 2 (SLC34A2). Our results suggest that additional Met supplementation with 20 ㎍/mL may promote the synthesis of milk proteins in bovine mammary epithelial cells under hyperthermia by inhibiting apoptosis, activating the AKT-mTOR-RPS6KB1 signalling pathway, and regulating the entry of amino acids into these cells.

• 한국미생물·생명공학회지
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• 제14권5호
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• pp.421-426
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• 1986

Lactobacillus casei YIT9018은 국내의 발효유제조에 널리 사용되고 있으며, 이에 대한 효과적인 동결건조 방법을 확립하기 위하여 glycine과 glutamic acid를 함유한 amino산 혼합액을 기본 현탁 배지로 사용하여 동결건조 및 rehydration을 실시하고 그 효과를 기존의 보호제들과 비교하였다. 아미노산 혼합액은 대조구에 비해서 현저한 동결보호 효과를 가지고 있었다. 또 glycine과 DL-glutamic acid는 단독 사용시보다 혼합할 경우 더욱 효과적이었으며 이때의 최적농도는 0.1M이었다. L. casei YIT9018주는 MRS 배지상에서 접종후 18시간만에 정상기에 들어갔으며 24시간 후에는 최대생육을 나타냈다. 또 이 24시간 균체가 동결건조에 대하여 가장 저항성이 큰 것으로 판명되었다. 아미노산 혼합액에 sucrose, lactose등의 이당류 및 NF-MS를 첨가하면 85％ 이상의 높은 생존율을 기대할 수 있으며, 최적농도는 당류의 경우 7.5-10％(w/v), NFMS의 경우는 10％정도였다. 이상의 결과로 보아 동결후의 생존율을 높이고 활력을 유지하기 위해서는 아미노산 혼합액에 NFMS의 첨가가 바람직하다고 생각되었다. 한편, rehydration media에 따라서도 생존율이 변하였는데 아미노산 혼합액은 대조구에 비해 약 3배의 동결 보호효과를 나타냈다.

• 미생물학회지
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• 제12권1호
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• pp.37-51
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• 1974

Three strains which accumulated large quantities of L-hlutamic acid as the chief product of metabolism in the presence of glucose and inorhanic ammonium salt under the aerobic condition sere newly isolated. These strains have the general characters as follows: Gram-positive, short fod-shaped, non-sporulating, non-motile, and facultative anaerobe. A change of cell shates was not almost observed in their life cycles and neither a phenomenon of cell-elongation nor a pleomorphism was recognized in any cases. Together with rigid stability in Gram-stain, these characters as above indicated evidences that newly isolates would belong to genus Brevibacterium clearly differentiated from genus Corynebacterium. At the same time the newly isolates, in addition to nutritional requirement of biotin and thiamine, showed the distinctive character of requirement of special amino acid such as histidine or cysteine for their considerable growth. These physiological characters including nitrates reduction, reaction on milk, and slow formation of acid from sugar also were useful in confirming that these bacteria would be Brevibacterium ammoniagenes.

• Asian-Australasian Journal of Animal Sciences
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• 제32권2호
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• pp.257-264
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• 2019

Objective: Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). Methods: Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to $500{\mu}g/mL$) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco's modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. Results: The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; ${\alpha}_{s2}$-casein increased 2-fold, ${\kappa}$-casein increased 5-fold, and the amount of unchanged ${\beta}$-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein ${\alpha}_{s2}$-casein, ${\kappa}$-casein, and ${\beta}$-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. Conclusion: Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.

• Journal of Animal Science and Technology
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• 제62권4호
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• pp.485-494
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• 2020

Limiting amino acids (AAs) for milk production in dairy cows fed on a concentrate diet of corn grain and soybean meal was evaluated in this study. Four lactating and multiparous Holstein cows (in third or fourth parities, with an average body weight of 633 ± 49.2 kg), 8 to 9 weeks into their lactation period, were used in a 4 × 4 Latin square design. The experiment comprised four dietary treatments: (1) no intravenous infusion (control); (2) control plus intravenous infusion of an AA mixture of 6 g/d methionine, 19.1 g/d lysine, 13.8 g/d isoleucine, and 15.4 g/d valine (4AA); (3) control plus intravenous infusion of the AA mixture without methionine (no-Met); and (4) control plus intravenous infusion of the AA mixture without lysine (no-Lys). All animals were fed on a controlled diet (1 kg/d alfalfa hay, 10 kg/d silage, 14 kg/d concentrate mixture, ad libitum timothy hay). The AA composition of the diet and blood were determined using an automatic AA analyzer. Milk composition (protein, fat, lactose, urea nitrogen, and somatic cell counts) was determined using a MilkoScan. The results showed that feed intake for milk production did not differ from that of intravenous infusion using a limiting AA mixture. The 4AA treatment numerically had the highest milk yield (32.4 kg/d), although there was no difference when compared with the control (31.2 kg/d), no-Met (31.3 kg/d), and no-Lys (31.7 kg/d) treatments. The concentration of AAs in blood plasma of cows in all treatments, mainly isoleucine and valine, increased significantly compared with that of control. The no-Met treatment increased (p < 0.05) the concentration of lysine in the blood relative to the control and no-Lys treatments, whereas the no-Lys treatment increased (p < 0.05) the concentration of methionine relative to the control and no-Met treatments. In conclusion, milk production increased when feeding 10 g/d methionine to the cows, together with their concentrate diet of corn grain and soybean meal.

• Animal Bioscience
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• 제34권4호
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• pp.489-498
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• 2021

Objective: Milk production is one of the most desirable traits in livestock. Recently, the toll-like receptor (TLR) has been identified as a candidate gene for milk traits in cows. So far, there is no information concerning the contribution of this gene in milk traits in sheep. This study was designed to investigate the TLR 4 gene polymorphisms in Barki ewes in Egypt and then correlate that with milk traits in order to identify potential single nucleotide polymorphisms (SNPs) for these traits in sheep. Methods: A part of the ovine TLR 4 gene was amplified in Barki ewes, to identify the SNPs. Consequently; Barki ewes were genotyped using polymerase chain reaction-single strand conformation polymorphism protocol. These genotypes were correlated with milk traits, which were the daily milk yield (DMY), protein percentage (PP), fat percentage (FP), lactose percentage, and total solid percentage (TSP). Results: Age and parity of the ewe had a significant effect (p<0.05 or p<0.01) on DMY, FP, and TSP. The direct sequencing identified a missense mutation located in the coding sequence of the gene (rs592076818; c.1710C>A) and was predicted to change the amino acid sequence of the resulted protein (p.Asn570Lys). The association analyses suggested a significant effect (p<0.05) of the TLR genotype on the FP and PP, while the DMY tended to be influenced as well (p = 0.07). Interestingly, the presence of the G allele tended to increase the DMY (+40.5 g/d) and significantly (p<0.05 or p<0.01) decreased the FP (-1.11%), PP (-1.21%), and TSP (-7.98%). Conclusion: The results of this study suggested the toll-like receptor 4 (TLR4) as a candidate gene to improve milk traits in sheep worldwide, which will enhance the ability to understand the genetic architecture of genes underlying SNPs that affect such traits.

• 한국식품과학회지
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• 제31권3호
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• pp.739-745
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• 1999

대두는 여러 생리활성 물질을 함유하고 있는 가격이 저렴한 양질의 식물성 단백질 공급원이다. 그러나 특유의 대두취와 난소화성으로 인해 소비가 제한되고 있어 이를 극복하기 위한 연구의 일환으로 혼합유산 균주 및 효모첨가에 따른 배양시간대별 당이용성 및 아미노산 변화를 측정하여 대두유내 당류와 아미노산들이 혼합균주에 의해 이용되는 경향과 이에 따른 산생성에 대하여 검토하였다. S. thermophilus와 Sac. uvarum로 발효된 처리구가 pH 4.45, 산도 0.86으로 산생성이 가장 우수하였으며, 대두내 당 이용성을 측정한 결과 L. acidophilus와 S. thermophilus로 발효된 처리구는 대두올리고당의 이용성이 다른 처리구에 비해 낮았고, Sac. uvarum과 혼합발효된 처리구들의 당이용성이 높은 것으로 나타났다. 이러한 결과는 Sac. uvarum과 혼합배양하였을 경우 Sac. uvarum이 생산하는 효소에 의해 대두내 과당류로부터 분해된 단당류를 유산균들이 이용하기 때문인 것으로 생각되며, 각 혼합균주의 아미노산 이용성에 있어서도 Sac. uvarum으로 혼합발효된 처리구가 유산균만을 혼합한 처리구에 비해 지속적인 아미노산 이용효율이 더 높게 나타났으며 이는 유산균과 효모의 서로 다른 단백질가수분해능에 의한 상호 보완작용에 기인한 것으로 생각된다.

• 한국미생물·생명공학회지
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• 제13권2호
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• pp.151-156
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• 1985

Lactobacillus helveticus YM-1 과 Streptococcus thermophilus CH-1을 환원탈지유 배지에 접종하여 생육특성 및 배양조건을 검토한 결과 두 균은 전형적인 공생을 나타냈으며 혼합배양시 최적 pH와 온도는 각각 6.5와 4$0^{\circ}C$였다. 또한 두 균 사이에는 단백질 분해력의 차이가 현저하였고 L.helveticus의 배양여액에는 S. thermophilus의 생육을 촉진시키는 물질이 함유되어 있음을 관찰하였다.

• 한국식품영양학회지
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• 제8권3호
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• pp.192-198
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• 1995

Cheese milk를 기질로 하여 pronase 등 protease와 palanatase ML 등 lipase를 이용하여 EMC를 제조하였다. Cheese milk 가수분해에 관여하는 각 protease의 반응 조건을 살펴본 결과, pronase-3$0^{\circ}C$, pH 7.0, PANCREATIO-4$0^{\circ}C$, pH 8.0, pacific protease-3$0^{\circ}C$, pH 7.0과 Asp. Sp. 기원 protease-5$0^{\circ}C$, pH 8.0에서 최대의 활성을 보였으며, lipase의 반응 조건은 pancreatic lipase-5$0^{\circ}C$, pH 8.0, palatase ML-5$0^{\circ}C$, pH 7.0과 Candida cylindracea 기원 lipase-4$0^{\circ}C$, pH 6.0 이었다. 최적 반응 조건에서 가수분해를 행한 결과 반응 시간이 증가할수록 유리아미노산의 양과 유리지방산의 양이 증가하는 경향을 보였다. Pacific protease와 pronase에 의해 가수분해시 0.67mg/ml과 0.74 mg/ml의 유리 아미노산을 생성하였으며, 유리 아미노산 중 glutamic acid와 leucine이 가장 많은 함량을 보였다. Candida cylidracea 기원 lipase를 이용하여 가수분해시 가장 많은 유리 지방산 생성량을 보였다. 각 EMC의 지방산 조성을 살펴본 결과 butyric acid, palmitic acid, stearic acid와 oleic acid의 함량이 보였다. Pancreatin에 의해 가수분해 후 각 lipase를 사용하여 제조한 EMC의 관능검사 결과, pancreatic lipase를 이용한 EMC가 가장 쓴맛이 강하였고, palatase에 의한 EMC는 가장 바람직한 cheese 향기를 가지고 있다.