Effects of dry period length on milk production and physiological responses of heat-stressed dairy cows during the transition period.

The objective of this study was to investigate the effects of a traditional dry period (60 d) versus a no dry period (0 d) on the milk production, physiological response, and metabolic status of dairy cows exposed to heat stress during the transition period. Holstein dairy cows (n = 15) with similar expected calving dates were randomly assigned to two different dry period lengths: (1) no dry period (n = 7) and (2) a traditional dry period of 60 days (n = 8). All cows were studied from 8 weeks before expected calving to 10 weeks after calving and experienced heat stress during the transition period. The results showed that cows with no dry period decreased their milk yield in subsequent lactation, but compensated for the loss of milk yield accounted for by additional milk yield before calving. The energy balance at postpartum was improved in cows with no dry period compared to cows with a traditional dry period. There were no significant differences in the physiological response and blood metabolites at postpartum between the dry period lengths of dairy cows exposed to heat stress during the transition period. Taken together, our results showed that omitting the dry period improved the milk production and metabolic status of dairy cows exposed to heat stress during the transition period.

Dual Biomarker Combining DNA Damage Repair Gene Mutations and PD-L1 Expression for Immune Checkpoint Inhibitors in Non-small Cell Lung Cancer.

BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs) improve long-term survival in advanced non-small cell lung cancer (NSCLC) and require robust predictive biomarkers for the selection of responders. This study investigated the optimal implementation of DNA damage repair (DDR) gene mutations to predict response to ICIs in real-world NSCLC patients. PATIENTS AND METHODS: We retrospectively reviewed 55 advanced NSCLC patients who had undergone targeted high-throughput sequencing and received ICIs. Patients with two or more DDR gene mutations were defined as DDR2 positive. RESULTS: The patients' median age was 68 (range=44-82) years, and 48 (87.3%) were men. Seventeen patients (30.9%) showed ≥50% high programmed death-ligand 1 (PD-L1) expression. Ten patients (18.2%) received an ICI-chemotherapy combination as first-line therapy, and 38 (69.1%) received ICI monotherapy as more than second-line therapy. Fourteen patients (25.5%) were DDR2-positive. The objective response rate of patients with DDR2-positive or PD-L1 ≥50% was 45.5%, and that of patients with DDR2-negative and PD-L1 <50% was 11.1% (p=0.007). In the PD-L1 low expression subgroup (<50%), patients with DDR2-positive had improved progression-free survival (PFS) and overall survival (OS) after ICIs compared to those with DDR2-negative (PFS: 5.8 vs. 1.9 months, p=0.026, OS: 14.4 vs. 7.2 months, p=0.078). DDR2-positive patients or those with PD-L1 ≥50% (24, 43.6%) had statistically significant improvement in PFS and OS after ICIs compared to DDR2-negative and those with PD-L1 <50% (PFS: 4.4 vs. 1.9 months, p=0.006, OS: 11.6 vs. 7.2 months, p=0.037). CONCLUSION: A dual biomarker combining DDR gene mutations and PD-L1 expression improves the prediction of response to ICIs in advanced NSCLC.

Silyl Tether-Assisted Photooxygenation of Electron-Deficient Enaminoesters: Direct Access to Oxamate Formation.

Photooxygenation reactions of electron-deficient enaminoesters bearing an oxophilic silyl tether at the α-position of the nitrogen atom using methylene blue (MB) were explored to develop a mild and efficient photochemical strategy for oxidative C-C double bond cleavage reactions via singlet oxygen (1O2). Photochemically generated 1O2, through energy transfer from the triplet excited state of MB (3MB*) to molecular oxygen (3O2), was added across a C-C double bond moiety of enaminoesters to form perepoxides, which rearranged to form dioxetane intermediates. The cycloreversion of the formed dioxetane via both C-C and O-O bond cleavage processes led to the formation of oxamates. Importantly, contrary to alkyl group tether-substituted electron-deficient enaminoesters that typically disfavor photooxygenation, the silyl tether-substituted analogues undergo this photochemical transformation efficiently with the assistance of a silyl tether, which facilitates formation of the perepoxide. The observations in this study provide useful information about photosensitized oxygenation reactions of unsaturated C-C bonds, and, moreover, this photochemical strategy can be utilized as a mild and feasible method for the preparation of diversely functionalized carbonyl compounds including oxamates.

Visible-Light-Induced Selective C-C Bond Cleavage Reactions of Dimeric ß-O-4 and ß-1 Lignin Model Substrates Utilizing Amine-Functionalized Fullerene.

Finding a selective and efficient fragmentation process under ambient conditions is pivotal for the generation of fuels and chemical feedstocks from lignoceullosic biomass. In the present study, visible-light and amine-functionalized fullerene-based photocatalyst-promoted photodegradation reactions of dimeric ß-O-4 and ß-1 lignin model compounds, containing varying numbers of methoxy substituents on the arene ring, were explored to find and develop mild, eco-friendly photochemical techniques for efficient delignification. The results showed that, in contrast to well-known organic photoredox catalysts, amine-functionalized fullerene photocatalyst promoted photochemical reactions of lignin model compounds could lead to more efficient lignin fragmentation reactions through a pathway involving a selective Cα-Cß bond cleavage process, and in addition, Cα-hydroxyl moiety in lignin model compounds played a significant role in the success of the Cα-Cß bond cleavage reaction of lignin model substrates.

Changes in milk production and blood metabolism of lactating dairy cows fed Saccharomyces cerevisiae culture fluid under heat stress.

In this study, Saccharomyces cerevisiae culture fluid (SCCF) has been added to a diet of lactating dairy cows to attempt to improve the ruminal fermentation and potentially increase the dry matter intake (DMI) and milk yield. This study was conducted to investigate the effects of SCCF on the milk yield and blood biochemistry in lactating cows during the summer. Twenty-four Holstein dairy cows were randomly assigned to one of four treatments: (1) total mixed ration (TMR-1) (Control); (2) TMR-1 supplemented with SCCF (T1); (3) TMR-2 (containing alfalfa hay) (T2); and (4) TMR-2 supplemented with SCCF (T3). SCCF (5 ml/head, 2.0×107 CFU/mL) was mixed with TMRs daily before feeding to dairy cows. The mean daily temperature-humidity index (THI) during this trial was 76.92 ± 0.51 on average and ranged from 73.04 to 81.19. For particle size distribution, TMR-2 had a lower >19 mm fraction and a higher 8-19 mm fraction than TMR-1 (p < 0.05). The type of TMR did not influence the DMI, body weight (BW), milk yield and composition, or blood metabolites. The milk yield and composition were not affected by the SCCF supplementation, but somatic cell counts were reduced by feeding SCCF (p < 0.05). Feeding SCCF significantly increased the DMI but did not affect the milk yield of dairy cows. The NEFA concentration was slightly decreased compared to that in the control and T2 groups without SCCF. Feeding a yeast culture of S. cerevisiae may improve the feed intake, milk quality and energy balance of dairy cows under heat stress.

Fluidized-Bed Granulation of Probiotics-Encapsulated Spray-Dried Skim Milk Powder: Effects of a Fluidizing Aid, Moisture-Activation and Dehydration.

A probiotic powder of poor flowability with high dust content, prepared by spray drying reconstituted skim milk fermented with Lactobacillus rhamnosus GG (LGG), was granulated by fluidized-bed granulation (FBG). The effects of the addition of skim milk powder (SMP) as a fluidizing aid, and of simple moisture-activation with or without dehydration, were investigated with respect to the performance of the FBG process. A fine, poorly fluidizable LGG powder (Geldart Group C) could be fluidized and granulated, with a 4- to 5-fold increase in particle size (d4,3 = 96-141 µm), by mixing with SMP (30-50%), which has larger, fluidizable particles belonging to Geldart Group A. Moisture-activation after the mixing, followed by fluidized-bed dehydration with hot air to remove excess moisture, further improved the FBG; the yield of the granules increased from 42% to 61% and the particle size distribution became much narrower, although the average particle size remained almost the same (d4,3 = 142 µm). These granules showed a popcorn-type structure in scanning electron microscopy images and encapsulated a sufficient level of viable LGG cells (1.6 × 108 CFU g-1). These granules also exhibited much better flowability and dispersibility than the spray-dried LGG powder.

Evaluation of heat stress responses in Holstein and Jersey cows by analyzing physiological characteristics and milk production in Korea.

We evaluated the effects of heat stress on physiological responses and milk production in Holstein and Jersey cows reared in Korea. The mean average temperature-humidity index (THI) increased significantly from May to August and then decreased until October. The mean average rectal temperature (RT) was increased in Holstein cows compared with Jersey cows, as the THI values increased from 61 to 85. The average respiratory rate (RR) was increased in Jersey cows compared with Holstein cows when the THI value increased from 61 to 85. The average surface temperature of the rumen and udder was higher in Jersey cows than in Holstein cows when the THI value increased from 61 to 85. No significant difference was noted with respect to relative serum volumes between the breeds and THI ranges, but we measured significant changes in serum pH in Holstein and Jersey cows when the THI value increased from 61 to 85. Milk production was not significantly changed in Holstein cows when the THI increased from 61 to 85, but milk production and milk protein content were significantly altered in Jersey cows when the THI increased from 61 to 85. Current study suggests that Holstein cows still have an advantage in terms of the economic returns of dairy farms in Korea. Therefore, further research is required regarding the heat tolerance of Jersey cows in Korean climatic conditions.

Effects of photoperiod and light intensity on milk production and milk composition of dairy cows in automatic milking system.

The purpose of this study was to determine the effects of photoperiod and light intensity on milk production, milk composition, hormones levels and blood metabolites indices of Korean Holstein dairy cows in automatic milking system (AMS). A total of 24 Holstein dairy cows were selected and used to four subsequent treatments for the experimental periods of 60 days. The light programs consisted of (1) Control: the natural photoperiod with 14.2 h of the light period and 9.4 h of the dark period (below 10 Lux); (2) T1: 16 h of the long day photoperiod (LDPP) with 50 Lux of light; (3) T2: 16 h of LDPP with 100 Lux of light; and (4) T3: 16 h of LDPP with 200 Lux of light, respectively. Importantly, there was a significant difference in the thurl activity of dairy cows between the different light intensity programs (p < 0.05). Milk yield was higher in T1 and T2 (40.80 ± 1.71 and 39.90 ± 2.02 kg/d, respectively) than those of Control and T3 (32.18 ± 1.51 and 35.76 ± 2.80 kg/d, respectively) (p < 0.05), but DMI was lower in T1, T2, and T3 compared to Control (p < 0.05). Also, milk fat percentage, the contents of milk fat and total solids were higher in T2 than those in the others (p < 0.05). The average daily melatonin level in milk was high to T3 (28.20 ± 0.43 pg/mL), T2 (24.62 ± 0.32 pg/mL), T1 (19.78 ± 0.35 pg/mL), and Control (19.36 ± 0.45 pg/mL) in order (p < 0.05). Also, the cortisol levels in milk and blood were lower in treatment groups than in Control (p < 0.05). The results of this study showed that it will be effective to improve the milk yield and milk composition, and to reduce the stress of dairy cows when the light conditions regulate to extend the photoperiod to 16 h at a light emitting diode (LED) intensity of 100 Lux under the AMS in dairy farm.

The effect of seasonal thermal stress on milk production and milk compositions of Korean Holstein and Jersey cows.

OBJECTIVE: In this study we investigated the effect of seasonal thermal stress on milk production and milk compositions between Holstein and Jersey dairy cows under the temperateclimate in Korea. METHODS: A total of 9 Holstein lactating dairy cows (2.0±0.11 parity) which had a daily milk yield of 29.77±0.45 kg, and days in milk of 111.2±10.29 were selected similarly at the beginning of the experiments in each season. Also, a total of 9 Jersey lactating dairy cows (1.7±0.12 parity) which had a daily milk yield of 20.01±0.43 kg, and days in milk of 114.0±9.74 were selected similarly at the beginning of the experiments. RESULTS: Results showed that the average ambient temperature (°C) and temperature-humidity index (THI) were higher in summer, and were lower in winter (p<0.05). The average relative humidity (RH, %) was higher in autumn than that of other seasons (p<0.05). Milk production was significantly decreased (Holstein 29.02 kg/d and Jersey 19.75 kg/d) in autumn than in other seasons (Holstein 30.14 kg/d and Jersey 20.96 kg/d). However, the milk production was negatively correlated in Holstein cows, and positively correlated in Jersey cows with THI values increased from 16 to 80. In addition, milk yield was increased by 15% in Holstein cows and decreased by 11% in Jersey cows with the THI values increased from 16 to 20. The fat and protein content percentage was significantly higher in Jersey milk than in Holstein milk, furthermore the fat and protein content yield was higher in Jersey cow milk than that of Holstein cow's milk with all THIs. CONCLUSION: From the study results, we concluded that Jersey cows might be less adaptable to low temperature of the winter, and this would have a negative impact on dairy farmer income since Korea's milk price estimation system places a higher value on milk yield than on milk compositions or sanitary grades.

Active maintenance of eligibility trace in rodent prefrontal cortex.

Even though persistent neural activity has been proposed as a mechanism for maintaining eligibility trace, direct empirical evidence for active maintenance of eligibility trace has been lacking. We recorded neuronal activity in the medial prefrontal cortex (mPFC) in rats performing a dynamic foraging task in which a choice must be remembered until its outcome on the timescale of seconds for correct credit assignment. We found that mPFC neurons maintain significant choice signals during the time period between action selection and choice outcome. We also found that neural signals for choice, outcome, and action value converge in the mPFC when choice outcome was revealed. Our results indicate that the mPFC maintains choice signals necessary for temporal credit assignment in the form of persistent neural activity in our task. They also suggest that the mPFC might update action value by combining actively maintained eligibility trace with action value and outcome signals.

A comparative study on milk composition of Jersey and Holstein dairy cows during the early lactation.

Recently, Jersey cattle was introduced and produced by embryo transfer to Korea. This study was conducted to investigate the differences of milk compositions between Jersey and Holstein cows and the relationship between days in milk (DIM) and milk compositions during early lactation. Data were collected from twelve lactating cows from Department of Animal Resources Development at National Institute of Animal Science. Cows in parity 1 were used, and calved at spring from April to March of 2017. All cows were housed in two sections within a free-stall barn, which divided into six from each breed, and received a basal total mixed ration. Milk samples of each cow were collected at 3 DIM and 30 DIM for analyzing the milk compositions, including fatty acids (FA), amino acids and minerals. Total solids, citrate, and milk urea nitrogen level were differed between the breeds (p < 0.05). As DIM went from 3 to 30, milk protein, total solids, and somatic cell count decreased (p < 0.05), but lactose increased in all breed milk (p < 0.05). Citrate and free fatty acid (FFA) elevated in Jersey milk (p < 0.05), whereas reduced in Holstein milk (p < 0.05). Proportions of some individual FA varied from the breeds. Myristic (C14:0), palmitic (C16:0), and arachidonic acid (C20:4) in milk from all cows were higher at 3 DIM than at 30 DIM (p < 0.05). Also, stearic (C18:0) and oleic acid (C18:1) were lower at 3 DIM than at 30 DIM (p < 0.05), and the C18:1 to C18:0 ratio was significantly differed in DIM × breed interactions (p < 0.05). The contents of the individual amino acids did not differ from the breeds. Calcium, phosphorous, magnesium, and zinc (Zn) contents was significantly increased in Holstein milk than Jersey milk at 3 DIM. Also, K and Zn concentrations were higher in Holstein milk than in Jersey milk at 30 DIM (p < 0.05). It was concluded that Jersey cows would produce more effective milk in processing dairy products and more proper energy status compared with Holstein cows in early lactation under the same environmental and nutritional conditions.

Preparation of Nanoemulsions of Vitamin A and C by Microfluidization: Efficacy on the Expression Pattern of Milk-Specific Proteins in MAC-T Cells.

In this study, we prepared stabilized vitamin A and C nanoemulsions, and investigated their efficacy on milk-specific proteins in bovine mammary epithelial cells (MAC-T). Emulsions of vitamin A (vit-A) and C (vit-C) were prepared using Lipoid S 75 and microfluidization. The particle size and polydispersity index (PDI) of nanoemulsified vit-A and vit-C were studied. The cytotoxic effect of nanoemulsion-free and nanoemulsified vit-A and vit-C was determined by an MTT assay. In addition, the efficacy of nanoemulsified vit-A and vit-C on the in vitro expression pattern of milk-specific proteins in MAC-T cells was investigated by quantitative RT-PCR. The results showed that the efficacies of stabilized nanoemulsions of vit-A and vit-C were 100% and 92.7%, respectively. The particle sizes were around 475.7 and 225.4 nm, and the zeta potentials were around -33.5 and -21.3 mV, respectively. The expression changes of αs2-, ß- and κ-casein were higher in the presence of a stabilized nanoemulsion of vit-A, compared with nanoemulsion-free vit-A. Furthermore, the expression changes of αs2- and ß-casein were lower and that of κ-casein was higher in the presence of a stabilized nanoemulsion of vit-C, compared with nanoemulsion-free vit-C. Thus, our findings demonstrate the efficacy of nanoemulsified vit-A and vit-C in changing the expression of milk-specific proteins in MAC-T cells.

The effect of nanoemulsified methionine and cysteine on the in vitro expression of casein in bovine mammary epithelial cells.

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 µg/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; αs2-casein increased 2-fold, κ-casein increased 5-fold, and the amount of unchanged ß-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 αs2-casein, κ-casein, and ß-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.

Effects of supplementing Barodon, Bacillus subtilis, and Ampbio on growth performance, biochemical metabolites, and hormone levels in Korean native heifers.

An experiment was conducted to evaluate the effects of supplementing feed additives of Barodon®, effective microorganism® (Bacillus (B.) subtilis), and Ampbio® on the growth performance, blood metabolites, stress, and reproductive hormone levels of Korean native heifers. A total of 48 Korean native heifers were assigned to four groups with 6 heifers in each group. The groups were control, Barodon (0.2%), beneficial microorganism (1%), and Ampbio (1%). Animals in all groups were fed a basal diet composed of selected feed additives and water ad libitum for 99 days. Results showed that there are significant changes in body weight and daily gain in the Ampbio-supplemented group as compared with the control and other feed additives groups (p < 0.05). The increased level of feed intake (7.30 ± 0.03 kg) and feed requirements (10.81 ± 0.52 kg) was observed in the Ampbio-fed group followed by the effective microorganism (EM), Barodon, and control groups. There were no significant changes in albumin, glucose, glutamic oxaloacetic transaminase (SGOT), serum pyruvic transaminase (SGPT), and total protein level, but the decreased levels of total cholesterol and triglycerides and the increased level of blood urea nitrogen were noted in the Ampbio-fed group as compared with the control and other feed additive groups. The reduced level of cortisol (p < 0.05) and elevated levels of progesterone and estradiol (p > 0.05) were noted in the Ampbio-fed group as compared to the other feed additive groups. It is therefore concluded that incorporation of Barodon, EM (B. subtilis), and Ampbio in the recommended diet improved the growth and health performance of Korean native heifers.

Production of chitinase from Escherichia fergusonii, chitosanase from Chryseobacterium indologenes, Comamonas koreensis and its application in N-acetylglucosamine production.

The important platform polysaccharide N-acetylglucosamine (GlcNAc) has great potential to be used in the fields of food, cosmetics, agricultural, pharmaceutical, medicine and biotechnology. This GlcNAc is being produced by traditional methods of environment-unfriendly chemical digestion with strong acids. Therefore, researchers have been paying more attention to enzymatic hydrolysis process for the production of GlcNAc. Hence, in this study, we isolated novel chitinase (Escherichia fergusonii) and chitosanase (Chryseobacterium indologenes, Comamonas koreensis) producing strains from Korean native calves feces, and developed the potential of an eco-friendly microbial progression for GlcNAc production from swollen chitin and chitosan by enzymatic degradation. Maximum chitinase (7.24±0.07U/ml) and chitosanase (8.42±0.09, 8.51±0.25U/ml) enzyme activity were reached in submerged fermentation at an optimal pH of 7.0 and 30°C. In this study, sucrose, yeast extract, (NH4)2SO4, and NaCl were found to be the potential enhancers of exo-chitinase activity and glucose, corn flour, yeast extract, soybean flour, (NH4)2SO4, NH4Cl and K2HPO4 were found to be the potential activator for exo-chitosanase activity. Optimum concentrations of the carbon sources for enhanced chitinase activity were 9.91, 3.21, 9.86, 1.66U/ml and chitosanase activity were 1.63, 1.13, 2.28, 3.71, 9.02, 4.93, and 2.14U/ml. These enzymes efficiently hydrolyzed swollen chitin and chitosan to N-acetylglucosamine were characterized by thin layer chromatography and were further confirmed by high-pressure liquid chromatography. From a commercial perspective, we isolated, optimized and characterized exochitinase from Escherichia fergusonii (HANDI 110) and chitosanase from Chryseobacterium indologenes (HANYOO), and Comamonas koreensis (HANWOO) for the large-scale production of GlcNAc facilitating its potential use in industrial applications.

Effect of fermented total mixed rations on the growth performance, carcass and meat quality characteristics of Hanwoo steers.

This study was conducted to assess the effects of fermented total mixed ration (FTMR) on the growth performance, carcass and meat quality traits of Hanwoo steers. The present study evidenced that the FTMR had a strong effect on dry matter intake, body weight, daily gain, slaughter weight and carcass characteristics compared with control animals. The results showed that the dry matter intake (7.17 ± 0.13 kg), average body weight (615.20 ± 112.82 kg), and daily gain (0.56 ± 0.16 kg) were greater in animals receiving FTMR than in control animals (P < 0.05). The meat quality characteristics indicated that cooking loss and the pH values did not vary between control and FTMR treated animals; however, animals in the treated groups (FTMR) had higher meat quality grades, carcass weight (396.13 ± 18.35), fat thickness (13.25 ± 1.75), marbling score (5.63 ± 0.56), meat color (40.06 ± 1.23), crude fat (18.39 ± 1.32) and sensory characteristics (flavor 5.03 ± 0.17; tenderness 4.42 ± 0.33; juiciness 5.10 ± 0.16). Nevertheless, the shear force values decreased significantly in FTMR-treated animals compared with control group steers. Overall, FTMR may not only improve the growth performance, biochemical metabolites, and fatty and acetic acid profiles of steers, but may also enhance the carcass and meat quality characteristics of Hanwoo steers. Regarding economics, our research findings suggest that FTMR-based feeds may enhance Hanwoo steer meat quality at a low cost.

The effect of lactation number, stage, length, and milking frequency on milk yield in Korean Holstein dairy cows using automatic milking system.

OBJECTIVE: The aim of the current study was to describe the relationship between milk yield and lactation number, stage, length and milking frequency in Korean Holstein dairy cows using an automatic milking system (AMS). METHODS: The original data set consisted of observations from April to October 2016 of 780 Holstein cows, with a total of 10,751 milkings. Each time a cow was milked by an AMS during the 24 h, the AMS management system recorded identification numbers of the AMS unit, the cow being milking, date and time of the milking, and milk yield (kg) as measured by the milk meters installed on each AMS unit, date and time of the lactation, lactation stage, milking frequency (NoM). Lactation stage is defined as the number of days milking per cows per lactation. Milk yield was calculated per udder quarter in the AMS and was added to 1 record per cow and trait for each milking. Milking frequency was measured the number of milkings per cow per 24 hour. RESULTS: From the study results, a significant relationship was found between the milk yield and lactation number (p<0.001), with the maximum milk yield occurring in the third lactation cows. We recorded the highest milk yield, in a greater lactation length period of early stage (55 to 90 days) at a 4× milking frequency/d, and the lowest milk yield was observed in the later stage (>201 days) of cows. Also, milking frequency had a significant influence on milk yield (p<0.001) in Korean Holstein cows using AMS. CONCLUSION: Detailed knowledge of these factors such as lactation number, stage, length, and milking frequency associated with increasing milk yield using AMS will help guide future recommendations to producers for maximizing milk yield in Korean Dairy industries.

Novel Acinetobacter parvus HANDI 309 microbial biomass for the production of N-acetyl-ß-d-glucosamine (GlcNAc) using swollen chitin substrate in submerged fermentation.

BACKGROUND: N-acetyl-ß-d-glucosamine (GlcNAc)6 is extensively used as an important bio-agent and a functional food additive. The traditional chemical process for GlcNAc production has some problems such as high production cost, low yield, and acidic pollution. Therefore, to discover a novel chitinase that is suitable for bioconversion of chitin to GlcNAc would be of great value. RESULTS: Here, we describe the complete isolation and functional characterization of a novel exo-chitinase from Acinetobacter parvus HANDI 309 for the conversion of chitin. The identified exo-chitinase mainly produced N-acetyl-d-glucosamine, using chitin as a substrate by submerged fermentation. The A. parvus HANDI 309 biofuels producing exo-chitinase were characterized by TLC, and was further validated and quantified by HPLC. Furthermore, the optimal temperature and pH for the exo-chitinase activity was obtained in the culture conditions of 30 °C and 7.0, respectively. The maximum growth of the stationary phase was reached in 24 h after incubation. These results suggest that A. parvus HANDI 309 biofuels producing exo-chitinases may have great potential in chitin to N-acetyl-d-glucosamine conversion. CONCLUSIONS: The excellent thermostability and hydrolytic properties may give the exo-chitinase great potential in chitin to GlcNAc conversion in industry. This is the first report that A. parvus HANDI 309 is a novel bacterial strain that has the ability to produce an enormous amount of exo-chitinase-producing bio-agents in a short time on an industrial scale without any pretreatment, as well as being potentially valuable in the food and pharmaceutical industries.

Evaluation of the nutritional value of locally produced forage in Korea using chemical analysis and in vitro ruminal fermentation.

OBJECTIVE: The use of locally produced forage (LPF) in cattle production has economic and environmental advantages over imported forage. The objective of this study was to characterize the nutritional value of LPF commonly used in Korea. Differences in ruminal fermentation characteristics were also examined for the LPF species commonly produced from two major production regions: Chungcheong and Jeolla. METHODS: Ten LPF (five from each of the two regions) and six of the most widely used imported forages originating from North America were obtained at least three times throughout a year. Each forage species was pooled and analyzed for nutrient content using detailed chemical analysis. Ruminal fermentation characteristics were also determined by in vitro anaerobic incubations using strained rumen fluid for 0, 3, 6, 12, 24, and 48 h. At each incubation time, total gas, pH, ammonia, volatile fatty acid (VFA) concentrations, and neutral detergent fiber digestibility were measured. By fitting an exponential model, gas production kinetics were obtained. RESULTS: Significant differences were found in the non-fiber carbohydrate (NFC) content among the forage species and the regions (p<0.01). No nutrient, other than NFC, showed significant differences among the regions. Crude protein, NFC, and acid detergent lignin significantly differed by forage species. The amount of acid detergent insoluble protein tended to differ among the forages. The forages produced in Chungcheong had a higher amount of NFC than that in Jeolla (p<0.05). There were differences in ruminal fermentation of LPF between the two regions and interactions between regions and forage species were also significant (p<0.05). The pH following a 48-h ruminal fermentation was lower in the forages from Chungcheong than from Jeolla (p<0.01), and total VFA concentration was higher in Chungcheong than in Jeolla (p = 0.05). This implies that fermentation was more active with the forages from Chungcheong than from Jeolla. Analysis of gas production profiles showed the rate of fermentation differed among forage species (p<0.05). CONCLUSION: The results of the present study showed that the nutritional values of some LPF (i.e., corn silage and Italian ryegrass) are comparable to those of imported forages widely used in Korea. This study also indicated that the nutritional value of LPF differs by origin, as well as by forage species. Detailed analyses of nutrient composition and digestion kinetics of LPF should be routinely employed to evaluate the correct nutritional value of LPF and to increase their use in the field.

The extracellular microenvironment explains variations in passive drug transport across different airway epithelial cell types.

PURPOSE: We sought to identify key variables in cellular architecture and physiology that might explain observed differences in the passive transport properties of small molecule drugs across different airway epithelial cell types. METHODS: Propranolol (PR) was selected as a weakly basic, model compound to compare the transport properties of primary (NHBE) vs. tumor-derived (Calu-3) cells. Differentiated on Transwell™ inserts, the architecture of pure vs. mixed cell co-cultures was studied with confocal microscopy followed by quantitative morphometric analysis. Cellular pharmacokinetic modeling was used to identify parameters that differentially affect PR uptake and transport across these two cell types. RESULTS: Pure Calu-3 and NHBE cells possessed different structural and functional properties. Nevertheless, mixed Calu-3 and NHBE cell co-cultures differentiated as stable cell monolayers. After measuring the total mass of PR, the fractional areas covered by Calu-3 and NHBE cells allowed deconvoluting the transport properties of each cell type. Based on the apparent thickness of the unstirred, cell surface aqueous layer, local differences in the extracellular microenvironment explained the measured variations in passive PR uptake and permeation between Calu-3 and NHBE cells. CONCLUSION: Mixed cell co-cultures can be used to compare the local effects of the extracellular microenvironment on drug uptake and transport across two epithelial cell types.