• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.203-211
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• 2020

Objective: Staphylococcus aureus (S. aureus) is one of the major microorganisms responsible for subclinical mastitis in dairy cattle. The present study was designed with the aim to explore the DNA methylation patterns using the Fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) techniques in a S. aureus-infected mouse model. Methods: A total of 12 out-bred Institute of Cancer Research female mice ranging from 12 to 13 weeks-old were selected to construct a mastitis model. F-MSAP analysis was carried out to detect fluctuations of DNA methylation between control group and S. aureus mastitis group. Results: Visible changes were observed in white cell counts in milk, percentage of granulocytes, percentage of lymphocytes, CD⁴⁺/CD⁸⁺ ratio (CD⁴⁺/CD⁸⁺), and histopathology of mice pre- and post-challenge with S. aureus. These findings showed the suitability of the S. aureus-infected mouse model. A total of 369 fragments was amplified from udder tissue samples from the two groups (S. aureus-infected mastitis group and control group) using eight pairs of selective primers. Results indicated that the methylation level of mastitis mouse group was higher than that in the control group. In addition, NCK-associated protein 5 (Nckap5) and transposon MTD were identified to be differentially methylated through secondary polymerase chain reaction and sequencing in the mastitis group. These observations might play an important role in the development of S. aureus mastitis. Conclusion: Collectively, our study suggests that the methylation modification in Nckap5 and transposon MTD might be considered as epigenetic markers in resistance to S. aureus-infected mastitis and provided a new insight into S. aureus mastitis research in dairy industry and public health.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.138-143
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• 2008

A study was conducted to evaluate nutritional value for twenty-one pork muscles. Ten market-weight crossbred pigs (five gilts and five barrows) were used for evaluating proximate chemical composition, cholesterol, total iron, calorie and fatty acid contents. As preliminary analysis revealed no noticeable sex effect, pooled data from both sexes were used for the final analysis. M. rectus femoris had the highest moisture content, while m. latissimus dorsi was lowest in moisture content (p<0.05). Protein content was highest for m. longissimus dorsi and lowest for m. supraspinatus (p<0.05). The tensor fasciae and latissimus dorsi muscles contained the highest intramuscular fat (p<0.05), while rectus femoris, adductor and vastus lateralis were lowest in intramuscular fat content. When simple correlations between chemical values were computed for the pooled dataset from all muscles, intramuscular fat had significant (p<0.05) negative linear relationships with moisture (r = -0.85) and protein (r = -0.51) contents. Calorie levels were not significantly affected by fat content, while rectus femoris and latissimus dorsi muscles showed lowest and highest calorie contents, respectively (p<0.05). Polyunsaturated fatty acid content was highest (p<0.05) for both m. adductor and m. rectus femoris, while it was lowest for m. longissimus dorsi. Collectively, the current study identified a large amount of variation in nutritional characteristics between pork muscles, and the data can be used for the development of muscle-specific strategies to improve eating quality of meats and meat products.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.157-162
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• 2013

The use of Korean native chicken is increasing, and the discovery of new genetic resources is very important from both economic and genetic conservation points of view. In this study, mtDNA D-loop sequences from 272 privately-owned Korean native chickens from a Hyunin farm were investigated. Seventeen nucleotide substitutions were identified from the sequence analysis and they were classified as 6 haplotypes. Previously investigated haplotypes in five Korean native chicken populations have been compared with the Hyunin chicken population. The results indicated that two haplotypes, H10 and H15, in the Hyunin chicken population were not previously identified in other Korean native chicken populations, representing 33.09% (90/272) and 1.1% (3/272) of the Hyunin population, respectively. On the other hand, four other haplotypes were identical to those of a previous study of Korean native chicken populations. This result is indicative of conservation strategies of Hyunin chicken populations for expanding the genetic diversity in the Korean native chicken population.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.603-607
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• 2001

This paper is based on the 36 wild Japanese quails which migrated to and settled in the Weishan Lake area. The gene frequency of 10 loci encoding the enzymes in viscera and muscle was detected. After collecting the same data about 20 quail colonies in China and other countries, it clusters the 21 quail populations by fuzzy cluster analysis. The study indicates that the wild Japanese quail in the Weishan Lake area is closer to domestic quail for phylogenetic system than wild Japanese quails in Japanese Islands. The paper supports the thesis that the quail domestication area should be further studied.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.133-140
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• 2013

The aim of this study was to investigate the behavioral changes of laying hens in an aviary system. In this study, 500 laying hens (Hyline brown) were held in an aviary system in a open-type poultry house. The behaviors of laying hens were recorded using CCD cameras and a digital video recorder. The data were scanned every 2 min to obtain an instantaneous behavioral sample. In the behaviors of laying hens, 'Feeding' and 'Drinking' increased from 3 d placing chick and stabilized after 5 d placing chick. 'Perching' increased from 19:00 to 05:00, while 'Nest visiting' increased from 06:00 to 18:00. 'Aggressive behavior' decreased gradually after 5 d placing chick. These results suggest that the behaviors of laying hens are changed rapidly for about 5 days after placing chick and the behaviors of the laying hens are almost stabilized at 5 d placing chick.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.141-148
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• 2013

This study was conducted to evaluate the effect of different housing systems on the performances of sows and their piglets during gestation. A total of 90 sows (Landrace ${\times}$ Yorkshire) were employed into 3 experimental farms to give 3 treatments, stall housing, group housing in either slatted floor or litter floor. Individual sow was used as an experimental unit. Group housed sows were fed with electronic sow feeder during gestation. Performance measures were taken on sows and piglets. Back-fat thickness and body condition score of sows were not affected by housing systems for pregnant sows. There was no difference of estrus interval of pregnant sows between housing systems. The lower number of still-birth was observed in group housing type. The number of wounded sows in slatted floor was remarkably increased compared with sows in litter floor. This study showed that the housing systems could fairly impact sow and piglet performances.

• Journal of Animal Environmental Science
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• v.20 no.4
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• pp.167-172
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• 2014

This study was conducted to evaluate the housing design on the feeding behaviors of group housed pregnant sows. A total of 65 sows (Landrace ${\times}$ Yorkshire) were employed into 2 experimental sow housing with different housing design. Lying area of one of sow housing was designed with concrete fence to give the shelter for weak sows. The other was floor type without any obstacles. Group housed sows were fed using electronic sow feeder (ESF) during gestation. Daily feeding pattern of sows was automatically recorded in ESF feeder program. Most sows ate all feed during night. Daily visiting frequency to ESF of sows in pig pen with the shelter was significantly lowered than sows in floor type pen. This study showed that the housing design of group housed sow pen could fairly impact ESF utilization of sow.

• Journal of Animal Science and Technology
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• v.59 no.2
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• pp.4.1-4.5
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• 2017

Background: Biofilms were the third-dimensional structure in the solid surface of bacteria. Bacterial biofilms were difficult to control by host defenses and antibiotic therapies. Escherichia coli (E. coli) and Salmonella were popular pathogenic bacteria that live in human and animal intestines. Essential oils are aromatic oily liquids from plant materials and well known for their antibacterial activities. Method: This study was conducted to determine effect of essential oil on anti-biological biofilm formation of E. coli and Salmonella strains in in vitro experiment. Two kinds of bacterial strains were separated from 0.2 g pig feces. Bacterial strains were distributed in 24 plates per treatment and each plates as a replication. The sample was coated with a Bacterial biofilm formation was. Result: Photographic result, Escherichia coli (E. coli) and Salmonella bacteria colony surface were thick smooth surface in control. However, colony surface in blended and single essential oil treatment has shown crack surface layer compared with colony surfaces in control. Conclusion: In conclusion, this study could confirm that essential oils have some interesting effect on anti-biofilm formation of E. coli and Salmonella strains from pig feces.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.673-680
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• 2021

The purpose of this study was to establish a basic principal procedure for the processing of cultured meat. The first stage involved isolating satellite cells from the desired muscle of an animal using enzymatic digestion (i.e., by using proteases, collagenases, and pronases). The second stage involved culturing the isolated muscle satellite cells in a growth medium containing fetal bovine serum and penicillin/streptomycin with growth factors for an optimal period of time. The second stage involved a basic method for the isolated muscle cells to proliferate while sub-culturing to further induce differentiation in gelatin-coated culture dishes with the general culture medium. The third stage involved the induction of differentiation of muscle satellite cells or formation of myotubes using myogenic medium. Lastly, the fourth stage involved the identification of cell differentiation or myotube formation (myogenesis) using fluorescent dyes. Moreover, the principle of these protocols can be applied to perform primary culture of animal cells. This study will assist beginners with the technical aspects of culturing meat (isolation, cultivation, and differentiation of muscle satellite cells as well as identification of myotube formation for myogenesis).

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2001.06a
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• pp.87-87
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• 2001