• Journal of Animal Science and Technology
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• v.57 no.10
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• pp.33.1-33.7
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• 2015

The objective of this study was to evaluate effects of a combined use of extracts of medicinal herbs Taraxaumi mongolicum, Viola yedoensis Makino, Rhizoma coptidis, and Radix isatidis (MYCI) on porcine epidemic diarrhea (PED). Twenty-two 3-day-old piglets received an oral challenge with $3{\times}10^{3.5}$ $TCID_{50}$ of the virulent PED virus (PEDV) in PBS or PBS only and daily oral administration of 60 mg of the MYCI mixture suspended in milk replacer or the vehicle for 7 days in a $2{\times}2$ factorial arrangement of treatments. Average daily gain (ADG) increased (p < 0.05) in response to the MYCI treatment in the PEDV-challenged piglets (-18 vs. 7 g for the vehicle- vs. MYCI-administered group), but not in unchallenged animals (27 vs. 28 g). Diarrhea score and fecal PEDV shedding, however, were not influenced by the MYCI treatment. The PEDV challenge caused severe intestinal villus atrophy and crypt hyperplasia, both of which were alleviated by administration of the MYCI mixture as indicated by an increase in the villus height and a decrease in the crypt depth due to the treatment. Overall, medicinal herb extracts used in this study ameliorated impaired growth performance and intestinal lesion of newborn piglets challenged with the virulent PEDV. Therefore, our results suggest that the MYCI mixture could be used as a prophylactic or therapeutic agent against PED.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.248-254
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• 1990

Commercial food grade porcine-pancreatic lipase was incorporated into cheese at two different levels of concentration and ripened at $7^{\circ},\;13^{\circ}\;and\;21^{\circ}C$ Gas chromatographic analysis showed that the pancreatic lipase-treated cheese produced significantly higher levels of short-chain free fatty acids than controls. At $21^{\circ}C$ the high level of pancreatic lipase-treated cheese produced medium flavor cheese at 1 wk and close to sharp flavor cheese at 3 wk without causing distinctive defects. The low level of pancreatic lipase-treated cheese developed a number of good quality cheese. They were roughly equivalent to medium and sharp cheeses when ripened at $7^{\circ},\;13^{\circ}\;and\;21^{\circ}C$ for 3 to 15wk. Statistical analyses indicated that there were significant correlations between aged Cheddar flavor and the concentration of c6 as individual short chain free fatty acids (FFA) or C4 and C6 FFA combinations. Pancreatic lipase may be applicable for the accelerated ripening of Cheddar cheese if appropriate conditions are used.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.111-116
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• 2011

Artificial insemination (AI) of swine is a very useful reproductive tool and that offers convenience in the Korean swine industry. Since many viruses have been reported to be excreted through boar semen, we investigated the presence of antibodies and antigens against viruses causing reproductive failure in semen of boar in 349 semen samples collected from six Korean AI centers. Viral antigens were detected by polymerase chain reaction (PCR) or reverse transcription-PCR predominantly. The results was as follows. The major reproductive failure causing factor was porcine circovirus type 2 (PCV2), followed by porcine reproductive and respiratory syndrome virus (PRRSV) ($X^2$=166.64, P<0.001). PCV2 and PRRSV, Japanese encephalitis virus (JEV), encephalomyocarditis virus (EMCV) was detected in 73 samples (20.9%), 44 samples (12.6%), 4 samples (1.1%), 3 samples (0.9%), respectively and porcine parvovirus in one sample (0.3%) Classical swine fever virus (CSFV), bovine viral diarrhea virus and Aujeszky's disease virus (ADV) were not detected. Enzyme-linked immunosorbent assay was carried out in 111 serum samples from three AI centers. In most pigs, antibodies response was showed prominently in CSFV (105 sera, 94.6%) ($X^2$=82.580, P<0.001), followed by, in PRRSV (100 sera, 90.1%), PCV2 (92 sera, 90.1%), and PPV (8 sera, 82.9%). ADV antibody was not detected. Thus, the experimental results will be used for the base data, with respect to the state of viral stillbirth in general pig farms, as well as AI centers and breeding farms in Korea.

• Korean Journal of Veterinary Service
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• v.37 no.4
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• pp.253-261
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• 2014

Porcine circovirus disease (PCVD) is a major problem of swine industry worldwide, and diagnosis of PCV2, causal agent of PCVD, has been doing in clinical laboratories of pig disease by polymerase chain reaction (PCR) methods. But the PCR analyses have a serious problem of misdiagnosis by contamination of DNA, in particular, from carryover contamination with previously amplified DNA or extracted DNA from field samples. In this study, an uracil DNA glycosylase (UNG)-based direct PCR (udPCR) without DNA extraction process and DNA carryover contamination was developed and evaluated on PCV2 culture and field pig samples. The sensitivity of the udPCR combined with dPCR and uPCR was same or better than that of the commercial PCR (cPCR) kit (Median diagnostics, Korea) on PCV2-positive serum, lymph node and lung samples of the pigs. In addition, the udPCR method confirmed to have a preventing ability of mis-amplification by contamination of pre-amplified PCV2 DNA from previous udPCR. In clinical application, 170 pig samples (86 tissues and 84 serum) were analysed by cPCR kit and resulted in 37% (63/170) of positive reaction, while the udPCR was able to detect the PCV2 DNA in 45.3% (77/170) with higher sensitivity than cPCR. In conclusion, the udPCR developed in the study is a time, labor and cost saving method for the detection of PCV2 and providing a preventing effect for DNA carryover contamination that can occurred in PCR process. Therefore, the udPCR assay could be an useful alternative method for the diagnosis of PCV2 in the swine disease diagnostic laboratories.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.65-71
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• 2002

We have utilized the PCR-RFLP method to detect the ryanodine receptor(RYR1) gene mutation and to estimate the genotype frequencies of the RYR1 gene in commercial crossbred pig population. The exon region(659bp) including point mutation(C ${\rightarrow}$T; Arg ${\rightarrow}$Cys) in the porcine ryanodine receptor gene, which is a causal mutation for PSS, was amplified by PCR and digested with Cfo I restriction enzyme. The RYR1 gene was classified into three genotypes by agarose gel electrophoresis. The normal homozygous(NN) individuals showed two DNA fragments consisted of 493 and 166bp. The mutant homozygous(nn) individuals showed only one DNA fragment of 659bp. Also, all three fragments(659, 493 and 166bp) were showed in heterozygous(Nn) carrier animals. The proportions of normal, carrier and PSS pigs within crossbred population of pigs were 81%, 15% and 4%, respectively. According to the results of analysis of variance for the association of genotypes of RYR1 of pigs at 30kg, day age at 90kg and average daily gains, the RYR1 nn genotype was very higher than RYR1 NN genotype for day age at 30kg with 5% level of significant difference, but no significant difference for association of any other genotypes with day age at 90kg and average daily gain in crossbred pigs. Therefore, DNA diagnosis by using PCR-RFLP analysis for the PSS gene was useful for large-scale screening of commercial pigs in the swine industry.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.291-297
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• 2021

Severe outbreaks of porcine epidemic diarrhoea virus (PEDV) have continued to re-emerge worldwide. Because of the high mortality rate of suckling piglets in PEDV outbreaks, the disease causes significant economic losses in the pig industry. The limited pre-existing immunity against this virus is thought to cause an explosive increase in infection in pig farms. This study aimed to evaluate the clinical symptoms of PEDV after intentional exposure (feedback). During the first few days of the outbreak in a breeding pig farm, 14 sows showed watery diarrhoea, and the disease subsequently spread rapidly throughout the barn. Pigs that were intentionally exposed to PEDV (n=251) showed watery diarrhoea (46.6%), reduced appetite (17.5%), and vomiting (6.0%). However, 75 exposed pigs (29.9%) showed no clinical signs of disease. Four weeks after the feedback challenge, 34 sows gave birth to litters of piglets, which survived with no diarrhoea. Five weeks after the start of the outbreak, PEDV was not detected in any of the examined samples, including environmental swabs. Thus, early diagnosis, prompt establishment of herd immunity, and strict application of biosecurity are good practices to reduce the mortality rates among new-born piglets and control economic losses in pig farms showing PEDV outbreaks.

• Journal of Veterinary Science
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• v.21 no.5
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• pp.79.1-79.12
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• 2020

Background: Recently, the pork industry of Thailand faced an epidemic of highly virulent strains of porcine reproductive and respiratory syndrome virus (PRRSV), which spread throughout Southeast Asia, including the Lao People's Democratic Republic and Cambodia. Hence, the rapid and on-site screening of infected pigs on a farm is essential. Objectives: To develop the new aptamer as a biosensor for detection PRRSV which are rapid and on-site screening of infected pig. Methods: New aptamers against PRSSV were identified using the combined techniques of capillary electrophoresis, colorimetric assay by gold nanoparticles, and quartz crystal microbalance (QCM). Results: Thirty-six candidate aptamers of the PRRSV were identified from the systematic evolution of ligands by exponential enrichment (SELEX) by capillary electrophoresis. Only 8 out of 36 aptamers could bind to the PRSSV, as shown in a colorimetric assay. Of the 8 aptamers tested, only the 1F aptamer could bind specifically to the PRSSV when presented with the classical swine fever virus and a pseudo rabies virus. The QCM was used to confirm the specificity and sensitivity of the 1F aptamer with a detection limit of 1.87 × 10¹⁰ particles. Conclusions: SELEX screening of the aptamer equipped with capillary electrophoresis potentially revealed promising candidates for detecting the PRRSV. The 1F aptamer exhibited the highest specificity and selectivity against the PRRSV. These findings suggest that 1F is a promising aptamer for further developing a novel PRRSV rapid detection kit.

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.698-719
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• 2023

Postweaning multisystemic wasting syndrome (PMWS) is caused by a systemic inflammation after porcine circovirus type 2 (PCV2) infection. It was one of the most economically important pathogens affecting pig production worldwide before PCV2 vaccine was first introduced in 2006. After the development of a vaccine against PCV2a type, pig farms gradually restored enormous economic losses from PMWS. However, vaccine against PCV2a type could not be fully effective against several different PCV2 genotypes (PCV2b - PCV2h). In addition, PCV2a vaccine itself could generate antigenic drift of PCV2 capsid. Therefore, PCV2 infection still threats pig industry worldwide. PCV2 infection was initially found in local tissues including reproductive, respiratory, and digestive tracks. However, PCV2 infection often leads to a systemic inflammation which can cause severe immunosuppression by depleting peripheral lymphocytes in secondary lymphoid tissues. Subsequently, a secondary infection with other microorganisms can cause PMWS. Eleven putative open reading frames (ORFs) have been predicted to encode PCV2 genome. Among them, gene products of six ORFs from ORF1 to ORF6 have been identified and characterized to estimate its functional role during PCV2 infection. Acquiring knowledge about the specific interaction between each PCV2 ORF protein and host protein might be a key to develop preventive or therapeutic tools to control PCV2 infection. In this article, we reviewed current understanding of how each ORF of PCV2 manipulates host cell signaling related to immune suppression caused by PCV2.

• Korean Journal of Veterinary Service
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• v.38 no.2
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• pp.71-75
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• 2015

Porcine salmonellosis is an economically important disease affecting the global pig industry today. Salmonella (S.) Typhimurium is highly contagious and may rapidly spread within pig populations of herd. To investigate the prevalence of porcine salmonellosis in Jeju, a total of 12,885 blood sera of 96 pig farms from 2009 to 2012 were analyzed by microplate agglutination test. Antibodies to S. Typhimurium were detected in all of pig farms tested in Jeju Province, and the mean of seropositive rate of individual pig was 18.8%. The mean seropositive rate of S. Typhimurium in sows (46.7%) was 7 times higher than that of weaned or growing pigs (6.7%). The lowest seropositive rate (3.0%) was detected in 40 day-old pigs, and this result might be closely associated with the marked decrease of maternal passive immunity. The seropositive rate in winter (42.7%) was higher than in other seasons.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.363-370
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• 2006

Porcine reproductive and respiratory syndrome (PRRS) is an economically important disease of swine that occurs all over the swine industry worldwide. It was first observed in the Unite States in 1987 then in Europe in 1990. It has been described in Japan and in Korea in 1993. PRRS virus is divided into two distinct types, North American and European, genetically. Based on our limited knowledge there has been no report on the existence of European PRRSV. But according to the government's Korea Customs Service there has been many importations of breeding pigs from Europe. These seem to make an estimate that European PRRSV could be introduced in Korea by inflow of European breeding pigs. We first detected the European PRRSV could be introduced in Korean pig farms by using polymerase chain reaction (PCR). Further, it is also identified that there are not only North American PRRSV antibody but also a European PRRSV antibody. According to the genetical and serological experiment results, the presence of established North American PRRSV in Korea is due to the use of live vaccines made of North American PRRSV strain as well field virus infection, and the European PRRSV is possibly introduced from imported breeding stock.