Korean veterinary medicine is a member of a major health profession with its own system of education, licensing, organization, and ethics, and a pioneering profession in his or her scientific knowledge and skills for the benefit society through the promotion of animal health, the relief of suffering, the conservation of livestock resources, the promotion of public health, biomedical work for medicine including comparative medicine, and the advancement of medical knowledge. This manuscript is to emphasize the role of the Korean public health veterinarians preparing the twenty-first century in public health service for humans.
The present study was conducted to investigate serotype distribution and biofilm formation of Actinobacillus (A.) pleuropneumoniae isolated from pneumonic lungs of pigs. A total of 37 A. pleuropneumoniae were isolated between January 2009 and June 2010. Serotypes of A. pleuropneumoniae isolates were determined using two different PCRs. The majority of isolates belonged to serotype 5 (n=31, 83.8%), and the others belonged to serotype 1 (n=4, 10.8%), and 2 (n=2, 5.4%), respectively. The ability of biofilm formation of the isolates was also determined by quantitative microtiter plate assay. Biofilm formation was observed in both 23 (62.2%) of the 37 field isolates and seven (43.8%) of the 16 reference strains. On the other hand, biofilm formation was various according to the serotypes: 20 (64.5%) of serotype 5, and three (75.0%) of serotype 1. However, two isolates of serotype 2 did not produce the biofilm in this study. Consequently, A. pleuropneumoniae serotype 5 was the most frequently detected (83.8% of the isolates), and 23 (62.2%) of 37 isolates exhibited biofilm positive phenotype in this study.
This study was carried out to investigate the antimicrobial resistance pattern and distribution of resistance gene determinants in fecal E. coli from chicken. Antimicrobial susceptibility test was performed on a total of 109 fecal E. coli isolates from chicken, collected in Gyeonggi, Chungbuk, Jeonnam and Jeonbuk province from March to November 2003, by the disk agar diffusion method. Eighteen commonly used antimicrobial agents approved in Korea as veterinary medicine were tested: ampicillin (AM), amoxicillin/clavulanic acid (AMC), cephalothin (CF), cefozolin (CZ), cefoxitin (FOX), cefotaxime (CTX), cefepime (FEP), imipenem (IPM), streptomycin (S), gentamicin (GM), amikacin (AN), ciprofloxacin (CIP), enrofloxacin (ENO), norfloxacin (NOR), trimethoprim/sulfamethoxazole (SXT), erythromycin (E), chloramphenicol (C) and tetracycline (TE). Higher resistance rates (≥50%) were observed against 9 antimicrobial agents including AM, CF, S, CIP, ENO, NOR, SXT, E and TE. Resistance was most frequent for TE in 105 E. coli isolates (96.3%). Twenty-two isolates (20.2%) of the isolates showed multiple antimicrobial resistance to 8, and 19 isolates (17.4%) showed to 7 antimicrobial agents. The distribution of the resistance gene determinants for S and TE was assessed by PCR in resistant isolates. Thirty isolates possessed the strA, strB, and aadA gene, 25 isolates possessed the strA and strB gene among the 66 streptomycin-resistant isolates. Fifty one isolates possessed only the tetA gene, 22 isolates possessed the tetA and tetB gene, 11 isolates possessed only the tetB gene among the tetracycline-resistant isolates.
This study was carried out to evaluate the microbiological characteristics of retail chicken meats stored under various conditions. Nine of whole chickens and nine of chicken breasts were used for bacterial analysis. Each chicken meat was divided into subsamples of 25 g each followed by storage at room temperature (25℃), refrigeration temperature (4 ℃), and freezing temperature (—20℃) for 180 min, 5 days, and 3 days, respectively. The standard plate counts were performed for the enumeration of the total aerobic bacteria. The number of aerobic bacteria was gradually increased by 1 log in samples held at the room temperature for 180 min. There was statistical difference in the number of bacteria between at 0 min and at 180 min of storage. For samples stored at 4℃ for 5 days, the number of bacteria was increased from 5.11 to 7.26 log CFU/g in chicken breast and 3.83 to 6.04 log CFU/g in whole chicken with statistical difference. No significant changes were observed in frozen chicken. The results of this study may provide useful information to consumers for proper storage and safe handling of chicken meats.
The lung and lymph node samples were collected from 786 pig farms associated with wasting and respiratory syndrome during 2005～2009. All samples were tested for the detection of porcine reproductive and respiratory syndrome virus (PRRSV) and the differentiation of its genotype using reverse transcriptase-polymerase chain reaction (RT-PCR). 643 farms (81.8%) of the pig farms examined were positive for PRRSV, of which 57.2% accounted for PRRSV type 1 and 70.2% accounted for PRRSV type 2. Furthermore, 37.5% of the farms positive for PRRSV, showed the coexistence of two genotypes. The results indicate that the PRRSV infections of single genotype or two genotypes are very common in Korean pig farms.
This study was carried out to investigate the distribution of disqualified boars tested on performance at the Second Korea Swine Testing Station from 2007 to 2009. Data used in this study were 6,758 records of Duroc, Landrace and Yorkshire breeding stocks which were registered in the herd book of the Korea Animal Improvement Association. Duroc breeding stocks tested performance were vastly outnumbered by Landrace and Yorkshire breeding stocks tested on performance. In disqualifying boars tested on performance, the Yorkshire was the most breeding stock. In the disqualifying factor in 2007, the shortage of index was the most factor. And the most of the disqualifying factors in 2008 and 2009 was the excess of daily age as reaching with 90㎏ body weight.
Selenium is an essential micronutrient which functions as an essential constituent of selenoproteins. The selenoproteins play an important role in the body’s defense from free radicals associated with chronic diseases such as cancer. The effect of selenium on colon carcinogenesis was investigated using an experimental animal model. Five-week old ICR mice were acclimated for one week, and fed on the Fe-overloaded diet (450 ppm) with different Se diets (0.02, 0.1 or 0.5 ppm) for 12 weeks. Animals were injected intraperitoneally with azoxymethane (AOM, 10 mg/㎏ B.W. weekly for 3 weeks), followed by 2% dextran sodium sulfate (DSS) in the drinking water for a week. There were three experimental groups including low Se group (Lse), medium (normal standard diet for mice) Se (MSe), and high Se (HSe). The numbers of aberrant crypt foci (ACF) and aberrant crypt (AC) were measured in the colonic mucosa. The iron and selenium concentrations in liver was measured using ICP-AES. Glutathione peroxidase (GPx) activity was determined in the liver and colon. TUNEL assay for cell apoptosis and proliferating cell nuclear antigen (PCNA) staining for cell proliferation were performed. Immunohistochemical staining of β-catenin was also performed in mucous tissue of colon. The dietary Se decreased the numbers of ACF/㎠ and AC/㎠ in a dose-dependent manner. HSe diet significantly decreased the numbers of AC/㎠, compared with LSe diet (p<0.05). The tumor incidence rate in low Se diet group was 5% higher than medium Se diet group and 20% higher than high Se diet group. The activities of GPx in the liver and colon were dependent on the content of dietary selenium. Apoptosis-positive cells were also increased by dietary Se in a dose-dependent manner. PCNA-positive staining was weak in high Se group. β-catenin stained area was increased in low Se group while it was decreased in high Se group. These findings indicate that dietary selenium exert a protecting effect on colon cancer by inhibiting the development of ACF/AC, increasing GPX and apoptosis, and decreasing cell proliferation and expression of β-catenin in mice.
Vanadium, a dietary micronutrient, has been reported to present interesting biological and pharmacological properties, including superoxide and nitric oxide scavenging effects. Low-dose ionizing radiation (LDR) is known to damage DNA and cause apoptosis of peripheral immunocytes by producing reactive oxygen species (ROS). The aim of this study was to elucidate the capacity of immune activation of Jeju water containing vanadium on immunosuppression caused by LDR. We examined the ROS production, DNA damage, cell apoptosis and proliferation of peripheral immunocytes in irradiated mice drinking different concentrations for 90 days; V0 (vanadium 0㎍/L, control), V1 (vanadium 15～20㎍/ L) and V2 (vanadium 20∼25㎍/L). Compared to V0 control where level of ROS showed tendency to increase, the ROS production was attenuated in peripheral immunocytes of irradiated mice drinking V1 and V2. DNA damage of peripheral immunocytes triggered by LDR significantly increased in mice drinking V0 compared to non-irradiated control, whereas V1 and V2 dramatically induced remission of DNA damage. On the observation of apoptosis of peripheral immunocytes, V1 and V2 showed the potency to reduce the number of apoptotic cells. On the other hand irradiated mice drinking V0 exhibited raised number of apoptotic cells. From the results obtained, we speculated that Jeju water containing vanadium (V1 and V2) has a potential role in decreasing DNA damage and apoptosis of immune cell by inhibiting ROS production. Consistent with this, Jeju water containing vanadium (V1 and V2) exhibits a capacity to enhance cell proliferation of peripheral immunocytes, which is suppressed by LDR as shown in V0 control. Collectively, Jeju water containing vanadium reduced DNA damage and apoptosis and induced the stimulatory potential on immunocytes. These results suggest that Jeju water containing vanadium sustained immune activities under immunosuppression caused by LDR.
A total of 222 udder-half milk samples of lactating goats were collected from two herds in Korea during 2008 and all samples were subjected to bacteriological examination. Somatic cell counts (SCC) were also determined for all samples except for 13 (5.9%), which were collected from halves of udders with clinical mastitis. A total of 85 bacteria were isolated from 82 (36.9%) of 222 milk samples tested. Staphylococci were the predominant pathogens, accounting for almost 70% of the isolates: Coagulase negative staphylococci (CNS) and S. aureus constituted 55% (47/85) and 14.1% (12/85), respectively. Among 209 samples tested for SCC, bacteria were isolated from 36 of 115 (31.3%) samples with SCC of <1×106 cells/㎖ and 38 of 94 (40.4%) samples that had SCC of ≥1×106 cells/㎖, respectively. All S. aureus were detected from samples with SCC of ≥1×106 cells/㎖, while 25 of 47 (61.0%) CNS were isolated from milk samples with SCC of <1×106 cells/㎖. Mean SCC of milk samples that harbored S. aureus and CNS was 4,787×103 cells/㎖ and >1×106 cells/㎖, respectively. All S. aureus and CNS isolates were susceptible to all antimicrobials tested except for penicillin, to which 2 (16.6%) S. aureus and 12 (25.5%) CNS isolates showed resistance.
This study was performed to estimate the seroprevalence of PRRSV in breeding farms in Jeju 2008 using a commercial enzyme-linked immunosorbent assay (ELISA) kit. The tested sera were randomly collected from a total of 1,947 sera from 9 breeding farms unvaccinated in Jeju. As a result, all breeding farms were seropositive for PRRSV. Seven hundred-eighty six of 1,947 sera (40.4%) were positive for PRRSV. Seropositve rate of PRRSV infection in 9 farms showed various levels: 1%, 8.9%, 9.1%, 43%, 46.9%, 48.2%, 51.6%, 60.9%, 85.5%, respectively. The results confirmed that PRRSV infection has been prevailing in breeding farms in Jeju. Also, these results must be taken into a consideration in strategy establishment for the control and eradication of PRRS.