Effects of resynchronization programs on pregnancy per artificial insemination, progesterone, and pregnancy-associated glycoproteins in plasma of lactating dairy cows

Thompson, I.M.,Cerri, R.L.A.,Kim, I.H.,Green, J.A.,Santos, J.E.P.,Thatcher, W.W. American Dairy Science Association 2010 Journal of dairy science Vol.93 No.9

Objectives were to develop a timed artificial insemination (TAI) resynchronization program to improve pregnancy per AI and to evaluate responses of circulating progesterone and pregnancy-associated glycoproteins in lactating cows. Cows (n=1,578) were presynchronized with 2 injections of PGF<SUB>2α</SUB>, given 14 d apart starting on d 45+/-3 postpartum, followed by Ovsynch [2 injections of GnRH 7 d before and 56h after injection of PGF<SUB>2α</SUB>, TAI 16h after second injection (d 0)]. The Resynch-treated cows received an intravaginal progesterone insert from d 18 to 25, GnRH on d 25, and pregnancy diagnosis on d 32, and nonpregnant cows received PGF<SUB>2α.</SUB>, GnRH 56h later, and TAI 16h later (d 35). The control cows were diagnosed for pregnancy on d 32 and nonpregnant cows received GnRH, PGF<SUB>2α</SUB> 39 d after TAI, GnRH 56h later, and TAI 16h later (d 42). Pregnancy was reconfirmed on d 60 after AI. Ovarian structures were examined in a subset of cows at the time of GnRH and PGF<SUB>2α</SUB> injections. Blood samples for analyses of progesterone and pregnancy-associated glycoproteins were collected every 2 d from d 18 to 30 in 100 cows, and collection continued weekly to d 60 for pregnant cows (n=43). Preenrollment pregnancies per AI on d 32 did not differ for cows subsequently treated as Resynch (45.8%, n=814) and control (45.9%, n=764), and pregnancy losses on d 60 were 6.7 and 4.0%, respectively. Resynchronized service pregnancy per AI (36%, n=441; 39.5%, n=412) and pregnancy losses (6.3 and 6.7%) did not differ for Resynch and control treatments, respectively. Days open for pregnant cows after 2 TAI were less for the Resynch treatment than for the control treatment (96.2+/-0.82 vs. 99.5+/-0.83 d). Cows in the Resynch treatment had more large follicles at the time of GnRH. The number of corpora lutea did not differ between treatments at the time of PGF<SUB>2α</SUB>. Plasma progesterone for pregnant cows was greater for Resynch cows than for control cows (18-60 d; 6.6 vs. 5.3ng/mL), and plasma concentrations of progesterone on d 18 were greater for pregnant cows than for nonpregnant cows (5.3 vs. 4.3ng/mL). Plasma pregnancy-associated glycoproteins during pregnancy were lower for cows in the Resynch treatment compared with control cows on d 39 (2.8 vs. 4.1ng/mL) and 46 (1.3 vs. 3.0ng/mL). Cows pregnant on d 32 that lost pregnancy by d 60 (n=7) had lower plasma concentrations of pregnancy-associated glycoproteins on d 30 than cows that maintained pregnancy (n=36; 2.9 vs. 5.0ng/mL). Pregnancy-associated glycoproteins on d 30 (>0.33ng/mL) were predictive of a positive d 32 pregnancy diagnosis (sensitivity=100%; specificity=90.6%). In conclusion, Resynch and control protocols had comparable pregnancy per AI for first and second TAI services, but pregnancy occurred 3.2 d earlier in the Resynch group because inseminations in the Resynch treatment began 7 d before those in the control treatment. Administration of an intravaginal progesterone insert, or GnRH, or both increased progesterone during pregnancy. Dynamics of pregnancy-associated glycoproteins were indicative of pregnancy status and pregnancy loss.

Alcohol dehydrogenase activity in Lactococcus chungangensis: Application in cream cheese to moderate alcohol uptake

Konkit, M.,Choi, W.J.,Kim, W. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.9

Many human gastrointestinal facultative anaerobic and aerobic bacteria possess alcohol dehydrogenase (ADH) activity and are therefore capable of oxidizing ethanol to acetaldehyde. However, the ADH activity of Lactococcus spp., except Lactococcus lactis ssp. lactis, has not been widely determined, though they play an important role as the starter for most cheesemaking technologies. Cheese is a functional food recognized as an aid to digestion. In the current study, the ADH activity of Lactococcus chungangensis CAU 28<SUP>T</SUP> and 11 reference strains from the genus Lactococcus was determined. Only 5 strains, 3 of dairy origin, L. lactis ssp. lactis KCTC 3769<SUP>T</SUP>, L. lactis ssp. cremoris KCCM 40699<SUP>T</SUP>, and Lactococcus raffinolactis DSM 20443<SUP>T</SUP>, and 2 of nondairy origin, Lactococcus fujiensis NJ317<SUP>T</SUP> and Lactococcus chungangensis CAU 28<SUP>T</SUP> KCTC 13185<SUP>T</SUP>, showed ADH activity and possessed the ADH gene. All these strains were capable of making cheese, but the highest level of ADH activity was found in L. chungangensis, with 45.9nmol/min per gram in tryptic soy broth and 65.8nmol/min per gram in cream cheese. The extent that consumption of cheese, following imbibing alcohol, reduced alcohol uptake was observed by following the level of alcohol in the serum of mice. The results show a potential novel benefit of cheese as a dairy functional food.

Short communication: Quantification of carbohydrates in whey permeate products using high-performance anion-exchange chromatography with pulsed amperometric detection

Lee, H.,MeloSilva, V.L.d.,Liu, Y.,Barile, D. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.11

A method was developed for the characterization and quantification of the disaccharide lactose and 3 major bovine milk oligosaccharides (BMO) in dairy streams. Based on high-performance anion-exchange chromatography-pulsed amperometric detection (HPAE-PAD), this method is advantageous because it requires minimal sample preparation and achieves good chromatographic separation of oligosaccharide isomers within 30min. The linear dynamic range and limit of detection were 0.1 to 10mg/L and 0.03 to 0.22mg/L, respectively. Mean recoveries of the BMO were excellent and ranged from 98.4 to 100.4%. Without complicated sample preparation procedures, this HPAE-PAD method measured BMO [3'-sialyllactose (3'SL), 6'-sialyllactose (6'SL), and 6'-sialyllactosamine (6'SLN)] and lactose using a single instrument, therefore increasing the accuracy of the measurement and applicability for the dairy industry. In colostrum whey permeate, 3'SL, 6'SL, and 6'SLN were 94, 29, and 46mg/L, respectively. This work is the first to demonstrate that some commercial products, currently marketed for supporting a healthy immune system, contain significant amounts of bioactive BMO and therefore, carry additional bioactivities.

The Effects of Dairy Processes and Storage on Insulin-Like Growth Factor-I (IGF-I) Content in Milk and in Model IGF-I-Fortified Dairy Products

Kang, S.H.,Kim, J.U.,Imm, J.Y.,Oh, S.,Kim, S.H. American Dairy Science Association 2006 Journal of dairy science Vol.89 No.2

The effects of several dairy processes on insulin-like growth factor-I (IGF-I) concentrations in milk and the storage stability of IGF-I-fortified dairy products were examined. The IGF-I content in raw milk determined by radioimmunoassay was significantly changed by the strength of heat treatments. In commercial manufacture of whole milk dry powder, IGF-I concentration was not significantly changed. A significant reduction in IGF-I content was found as the result of fermentation with a commercial starter culture. The IGF-I content in fortified milk and dried milk powder exhibited no significant changes over the tested storage periods (12 d for milk, 4 wk for dried milk powder), but the IGF-I content in the yogurt decreased significantly during storage. The use of IGF-I was varied by lactic strains and was apparent in the viable cells. When IGF-I was encapsulated using the surface-reforming process, the remaining IGF-I content after fermentation was significantly higher compared with that of the untreated control. Therefore, enteric coating of IGF-I before fermentation might be an effective method for the prevention of IGF-I degradation during fermentation.

Short communication: Bacteriocin KC24 produced by Lactococcus lactis KC24 from kimchi and its antilisterial effect in UHT milk

Han, E.J.,Lee, N.K.,Choi, S.Y.,Paik, H.D. American Dairy Science Association 2013 Journal of dairy science Vol.96 No.1

The severity of Listeria monocytogenes infections emphasizes the need for prevention or elimination of the pathogen from dairy products. Lactococcus lactis KC24, isolated from kimchi, exhibited an antimicrobial effect against food pathogens, including L. monocytogenes ATCC 15313. Lactococcus lactis KC24 was cultured in a 5-L jar fermenter at 35<SUP>o</SUP>C, and bacteriocin activity was maximal at 4h of incubation and persisted for 20h. Bacteriocin KC24 was inactivated by protease XIV, indicating that it has a proteinaceous nature. Bacteriocin activity was maintained at pH 3.0 to 9.0 and at temperatures of 50 to 121<SUP>o</SUP>C. The mode of inhibition against L. monocytogenes ATCC 15313 was shown to involve a bactericidal effect by treatment with 100 and 200 arbitrary units (AU)/mL of bacteriocin KC24. To test the activity of bacteriocin KC24 in a food product, bacteriocin KC24 and nisin (100 and 200AU/mL) with 4 log cfu/mL of a mixed culture of L. monocytogenes (ATCC 15313, ScottA, H7962, and H7762) were applied to UHT milk. Compared with the control, treatment with bacteriocin KC24 completely inhibited the growth of L. monocytogenes and resulted in no detectable L. monocytogenes after 14d at 4<SUP>o</SUP>C, whereas nisin moderately inhibited L. monocytogenes, resulting in a final concentration after 14d at 4<SUP>o</SUP>C higher than the initial inoculum. Bacteriocin KC24 may prove useful in improving the safety of dairy products.

Transcriptomic analysis of Lactococcus chungangensis sp. nov. and its potential in cheese making

Konkit, M.,Kim, J.H.,Bora, N.,Kim, W. American Dairy Science Association 2014 Journal of dairy science Vol.97 No.12

Lactococcus lactis has a played a prominent role in food industry from traditional milk fermentations to industrial scale processes. Extensive studies on the biochemical, physiological, and genetic aspects of L. lactis are evident from published literature. Recently, another novel species, Lactococcus chungangensis, was isolated from activated sludge as the sixth member of the genus to be discovered. To date, no study has been conducted to explore the functional aspects of L. chungangensis to identify features similar to those in L. lactis that are relevant to the dairy industry. Hence, the present study was undertaken to identify functional genes relevant to dairy application through comparative transcriptomic analysis of L. chungangensis with L. lactis. In expression microarray data, 415 genes were upregulated and 1,500 were downregulated of the total 1,915 probes analyzed. Interesting findings from this study were the identification of functional genes such as aminohydrolase and S-adenosylmethionine in L. chungangensis, which are useful in flavor production in cheese making. Probing these genes by PCR and analyzing the sequence confirmed the presence of these genes. Phenotypic analysis of these genes was also investigated by growing the strain in different concentrations of skim milk media to confirm the ability of L. chungangensis to degrade casein in milk, which is the major precursor for flavor enhancing compounds. Other adaptive and stress-response genes such as cold shock and heat shock proteins were also revealed. All experimental investigations at the functional level suggest that L. chungangensis possesses some interesting genes which are of commercial significance, especially in cheese production.

Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry

Ko, K.Y.,Park, S.R.,Lee, C.A.,Kim, M. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.3

Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 @?g/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry.

Phenotypic and Genetic Antibiogram of Methicillin-Resistant Staphylococci Isolated from Bovine Mastitis in Korea

Moon, J.S.,Lee, A.R.,Kang, H.M.,Lee, E.S.,Kim, M.N.,Paik, Y.H.,Park, Y.H.,Joo, Y.S.,Koo, H.C. American Dairy Science Association 2007 Journal of dairy science Vol.90 No.3

Staphylococcus aureus belongs to the group of major contagious mastitis pathogens, whereas the coagulase-negative staphylococci (CNS) are also capable of causing opportunistic bovine mastitis. Many of these strains are resistant to penicillin or ampicillin because of the long-term use of β-lactam antibiotics in agricultural and healthcare settings. Based on the simple and highly specific coagulase genotyping by PCR-RFLP used for discriminating among Staph. aureus strains, the relationship between phenotypic antibiogram and the polymorphism of coagulase gene was determined in this study. The staphylococci strains (835 Staph. aureus and 763 CNS) were isolated from 3,047 bovine mastitic milk samples from 153 dairy farms in 8 provinces from 1997 to 2004 in the Republic of Korea. Twenty-one (2.5%) Staph. aureus and 19 (2.4%) CNS strains were resistant to methicillin [oxacillin minimum inhibitory concentration (MIC) >=4μg/mL]. The mecA gene was also found in 13 methicillin-resistant Staph. aureus (MRSA) and 12 methicillin-resistant CNS (MRCNS) isolates with a significantly higher detection rate of the mecA gene in MRSA with high MIC (>=16μg/mL) compared with those with MIC@?8μg/mL. Methicillin-resistant Staph. aureus and MRCNS were also more resistant to other antibiotics (ampicillin, cephalothin, kanamycin, and gentamicin) than methicillin-susceptible staphylococci. Among 10 different coa PCR-RFLP patterns (A to J) in 706 Staph. aureus strains, the main types were A (26.9%), B (17.0%), G (10.5%), and H (15.4%), with the frequent observation of the A and H types (6 and 10 isolates) in MRSA. This study indicates that major epidemic Staph. aureus clones may be spread between different dairy farms, and the profile of coa genotype can be applied for epidemiological investigations and control of bovine mastitis, particularly one caused by MRSA with specific prevalent coa types.

Physicochemical, microbial, and sensory properties of yogurt supplemented with nanopowdered chitosan during storage

Seo, M.H.,Lee, S.Y.,Chang, Y.H.,Kwak, H.S. American Dairy Science Association 2009 Journal of dairy science Vol.92 No.12

This study was carried out to determine the possibility of adding nanopowdered chitosan (NPC) into cholesterol-reduced yogurt to improve the functionality of yogurt and the effects of adding NPC on the physicochemical, microbial, and sensory properties of the products during storage. The pH values and mean lactic acid bacteria counts of NPC-added (0.3 to ∼0.7%, wt/vol) and cholesterol-reduced yogurt ranged from 4.19 to 4.41 and from 4.75x10<SUP>8</SUP>to 9.70x10<SUP>8</SUP>fu/mL, respectively, when stored at 4<SUP>o</SUP> for 20 d, thereby indicating a possibility of prolonging the shelf life of yogurt. In color, the a* and b* values for cholesterol-reduced yogurt were not significantly influenced by the addition of NPC (0.1 to ∼0.7%, wt/vol); however, the L* values significantly decreased with the addition of the greatest concentration (0.7%, wt/vol) of NPC at 0-d storage. The sensory test revealed that the astringency scores significantly increased at 0-d storage when the greatest concentration (0.7%, wt/vol) of NPC was added into cholesterol-reduced yogurt. Based on the data obtained from the current study, it is concluded that concentrations (0.3 to ∼0.5%, vol/vol) of NPC could be used to produce an NPC-added and cholesterol-reduced yogurt without significantly adverse effects on the physicochemical, microbial, and sensory properties.

Use of Whey Permeate for Cultivating Ganoderma lucidum Mycelia

Song, M.,Kim, N.,Lee, S.,Hwang, S. American Dairy Science Association 2007 Journal of dairy science Vol.90 No.5

A novel approach to utilizing whey permeate, the cultivation of mycelia of the edible mushroom Ganoderma lucidum, is introduced. The major objective of this research was to use whey permeate as an alternative growth medium for the cultivation of mycelia of edible mushroom G. lucidum and to find an optimum condition for solid-state cultivation. Response surface analysis was applied to determine the combination of substrate concentration (25 to 45g of lactose/L), pH (3.5 to 5.5), and temperature (25 to 35<SUP>o</SUP>) resulting in a maximal mycelial growth. The radial extension rates, estimated by measuring the diameters of growing colonies on the Petri dishes, were used as the growth of the mycelia at different conditions. In the model, pH and temperature significantly affected mycelial growth, but lactose concentration did not. The condition predicted to maximize the radial extension rate of 17.6+/-0.4 mm/d was determined to be pH 4.4 and temperature 29.4<SUP>o</SUP>. Therefore, the results suggest that whey permeate could be utilized as a growth substrate for the cultivation of mycelia from the edible mushroom G. lucidum, enhancing the use of this by-product by the cheese manufacturing industry.