Escherichia coli is one of the major causative infectious agents of diarrhea in preweaning and postweaning pigs and leads to a large economic loss worldwide. However, there is limited information on the distribution and virulence genes in E. coli isolated from diarrheic piglets, which also applies to the current status of pig farms in Korea. To investigate the prevalence of virulence-associated genes in E. coli related to diarrhea in piglets, the rectal swab samples of diarrheic piglets were collected from Seoul National University’s veterinary pathological department between 2022 and 2023. E. coli strains were identified using the VITEK II system. Two sets of multiplex PCRs and one single PCRs used to detect 10 E. coli virulence genes. As a result, a total of 145 E. coli isolates were identified encoding one or more of the virulence genes. Among them, the prevalence of individual virulence gene was as follows, piglets virulence genes were STa 58.6%(85/145), STb 22.1%(32/145), LT 15.2%(22/145), EAST1 24.8%(36/145), Stx2e 6.9%(10/145), F4 31.7%(46/145), F5 1.4%(2/145), F6 11.7%(17/145), F18 4.1%(6/145), and F41 0.7%(1/145) respectively. These results suggest that E. coli disease in piglets may not be associated with a single toxin or a major gene combination, but with more varied and complex toxins and their combinations in Korea.

On pig farms, the highest mortality rate is observed among nursing piglets. To reduce this mortality rate, farmers need to carefully observe the piglets to prevent accidents such as being crushed and to maintain a proper body temperature. However, observing a large number of pigs individually can be challenging for farmers. Therefore, our aim was to detect the behavior of piglets and sows in real-time using deep learning models, such as YOLOv4-CSP and YOLOv7-E6E, that allow for real-time object detection. YOLOv4-CSP reduces computational cost by partitioning feature maps and utilizing Cross-stage Hierarchy to remove redundant gradient calculation. YOLOv7-E6E analyzes and controls gradient paths such that the weights of each layer learn diverse features. We detected standing, sitting, and lying behaviors in sows and lactating and starving behaviors in piglets, which indicate nursing behavior and movement to colder areas away from the group. We optimized the model parameters for the best object detection and improved reliability by acquiring data through experts. We conducted object detection for the five different behaviors. The YOLOv4-CSP model achieved an accuracy of 0.63 and mAP of 0.662, whereas the YOLOv7-E6E model showed an accuracy of 0.65 and mAP of 0.637. Therefore, based on mAP, which includes both class and localization performance, YOLOv4-CSP showed the superior performance. Such research is anticipated to be effectively utilized for the behavioral analysis of fattening pigs and in preventing piglet crushing in the future.

Enterotoxigenic Escherichia coli는 신생 및 이유기 돼지 설사의 주요 원인체로서 전세계적으로 양돈산업에 큰 경제적 손실을 끼치고 있다. 그러나 현재 국내에는 이러한 E. coli가 보유하는 다양한 병원성유전자의 분포 및 특성에 대한 정보가 부족한 실정이다. 이에 본 연구에서는 2013년부터 2016년까지 국내 163개 양돈농장에서 이유기 설사증 개체로부터 면봉스왑 샘플을 채취하여 동일 농장의 개체일 경우 5개에서 10개 정도를 혼합한 후, MacConkey agar에 배양하여 최종 API 32E system을 통하여 동정하였다. 분리된 모든 균주에 대해서 3가지의 다른 multiplex PCR을 수행하여 총 13종의 병원성유전자의 분포를 확인하였다. 이를 통하여 총 172개의 최소 한가지 이상의 병원성 유전자를 가지는 E. coli 균주를 확인하였고, 그 결과 병원성 유전자의 분포는 (1) fimbrial adhesins (43.0%): F4 (16.9%), F5 (4.1%), F6 (1.7%), F18 (21.5%), and F41 (3.5%); (2) toxins (90.1%): LT (19.2%), STa (20.9%), STb (25.6%), Stx2e (15.1%), EAST1 (48.3%); and (3) nonfimbrial adhesin (19.6%): EAE (14.0%), AIDA-1 (11.6%) and PAA (8.7%)로 나타났다. 결론적으로 본 연구결과는 국내 양돈농장의 이유기 설사증에 관연하는 E. coli는 다양한 종류의 병원성 유전자를 가지고 있으며 그러한 병원성 유전자의 조합도 매우 다양하게 분포하고 있음을 나타낸다.

To evaluate alterations in fecal bacterial compositions in weaning piglets after supplementation with Phellodendron Cortex extract (PCE), piglets were allowed freely to consume feed containing 10 ppm of PCE for 7 weeks. During the feeding period, fecal samples were collected from individual piglets. A total of 578 valid sequence reads were generated from 40 fecal samples of normal piglets before supplementation with PCE. Fifteen classes were identified. Approximately 90% of classifiable sequences belonged to Clostridia and Bacilli classes. The abundance of Clostridium spp. and Lactobacillus spp. was determined based on the results of the sequencing. The supplementation with 10 ppm PCE for 3 weeks increased the numbers of Clostridium spp. and Lactobacillus spp. whereas seven weeks of supplementation with PCE reduced their abundance. In vitro, PCE inhibited the growth of E. coli and Salmonella enteritidis in a dose-dependent manner.

This study was conducted to clarify behavior and body weight of weaned piglets between different social experiences during suckling period. Control (no social experience) and treatment (social experience) groups of weaned piglets were housed and observed with the aid of video technology for 8 consecutive hours in early (days 1 and 2) and late (days 22 and 23) periods after mixing. Inactive, locomotion and exploration were significantly different between control and treatment groups in early mixed period. Feeding differed between groups in late mixed period. In social behaviors, agonistic and interaction with adjacent pen were significantly higher in treatment group than in control group during early mixed period. However, social behaviors dramatically decreased in late mixed period. There was negative correlation between average daily gain of body weight and agonistic behavior. In social experienced weaned piglet groups, there were less agonistic behavior and more daily gain of body weight in this study. Social experience during suckling period would be useful for stable group management in swine industry.

The present study investigated the effects of dietary supplementation of purified amino acid (PAA) isolated and purified from animal slaughter house blood on growth performance and immune response of weanling piglets. A total of fifteen, 28 days old, weaned pigs were randomly distributed into three treatment groups, 5 pens per treatment (one head per pen). Each experimental diet was provided to five piglets per group (T0, 0% PAA; T1, 0.1% PAA; T2, 0.5% PAA). The feed consumption was calculated daily and body weight on a weekly basis. The blood samples were analyzed for plasma concentration of biochemical parameters and cytokines using ELISA Kit assay. Pigs fed with the 0.5% PAA have greater average daily weight gain (ADG) and feed efficiency (FE) as compared to those of T0 and T1. However, ADG and FE of T0 and T1 have no remarkable differences. The plasma cytokine levels were lower in T2 as compared to T0 and T1. The blood parameters like total bilirubin, blood urea nitrogen (BUN), glutamate oxalate transaminase (GOT) and glutamate pyruvate transaminase (GPT) were within the normal range in all the treatment groups. The study indicated that supplementation of 0.5% PAA have positive effect on the growth performance of the weanling pigs. Moreover, supplementation of the amino acid isolated and purified from animal slaughter house blood has no adverse effect on palatability of the feed and health of the animals.

Swine industry has been focusing selection of excellent breeding pigs for post decades. This result is created to superior breeding sows with larger litter size, which are leads to low birth weight piglets (LBW) because of intrauterine growth retardation. The LBW on development of pigs have well known to postpone growth performance and to disrupt body metabolisms than normal birth weight piglets (NBW). However, effect of LBW on reproductive functions is very not documented. Therefore, this study was conducted to identify effect of birth weight on reproductive function in the LBW compared with normal birth weight piglets (NBW) by RNA sequencing and pathway studio. The experimental animals utilized 3d old LBW (0.96±95.07 kg, n=4) and NBW (1.69±83.39 kg, n=4). The differentially expressed genes were approximately 800 genes above 2 fold. The genes were related to steroid hormone synthesis, estrogen receptors signaling and growth and proliferation of cells. These results may be suggested to affect development of reproductive organ. However, our data are restricted using young experimental animals.

Although piglets have been delivered by embryo transfer (ET) with in vitro produced (IVP) embryos and blastocysts, a success rate has still remained lower level. Unlike mouse, human, and bovine, it is difficult to a production of piglets by in vitro fertilization (IVF) because of an inappropriate in vitro culture (IVC) system in pig. Therefore, the present study was conducted to investigate whether minimized exposure time in IVC can improve the pregnancy and delivery rates of piglets. Immediately after IVM, the oocytes were denuded and co-incubated with freshly ejaculated boar semen for 3.5 to 4 hours at 38.5 ˚C under 5% CO2 in air. To avoid long-term exposure to in vitro state, we emitted IVC step after IVF. After that the presumptive zygotes were transferred into both oviducts of the surrogate on the same day or 1 day after the onset of estrus. Pregnancy was diagnosed on day 28 after ET and then was checked regularly every month by ultrasound examination. The 3 out of 4 surrogates were determined as pregnant (75%) and a total of 5 piglets (2 females and 3 males) were delivered at 118.3 ± 2.5 days of pregnancy period. In conclusion, a short-term exposure time may be an important factor in the production of IVP-derived piglets. It can be apply to the in vitro production system of transgenic pig by IVF, cloning, and pronuclear microinjection methods.

We previously developed a novel attenuated Salmonella Typhimurium (S.Typhimurium) △lon△cpxR vaccine. This study was conducted in order to examine whether this vaccine could effectively protect growing piglets against Salmonella infection. Pregnant sows in group A were primed and boosted with the vaccine, whereas pregnant sows in group B received sterile PBS-sucrose. After farrowing, newborn piglets in groups A and B were challenged with a wild type virulent S. Typhimurium at three weeks of age. During the study, serum IgG titers of piglets in group A were significantly higher than those of piglets in group B (P<0.001). In addition, clinical signs were observed in 5.9% of piglets in group A during the entire experimental period after the challenge, while diarrhea was observed in 81.6% of piglets in group B. These results indicate that vaccination of the pregnant sows resulted in effective protection in piglets against Salmonella infection.

Hemorrhagic Escherichia coli (E. coli) is one of the most important agent of diarrhea in piglet. The aim of this study was to investigate the characteristics of virulence genes and genetic diversity in hemorrhagic E. coli isolated from piglets with diarrhea. Among 122 hemorrhagic E. coli, 62 isolates carried single toxin gene like heat-stable toxin (ST), heatlabile toxin (LT), verotoxin 1 (VT1), verotoxin 2 (VT2), spa and eae. The most prevalent toxin gene carried by isolates was ST gene (23 isolates), while the most common association was ST/LT (14 isolates) and ST/LT/VT2 (13 isolates). In pulsed field gel electrophoresis, isolates were not classified as one cluster by epidemiological information including isolated area, isolated year and possessed toxins.

This study was conducted to investigate the effects of donor cell treatments on the production of transgenic cloned piglets. Ear fibroblast cell obtained from NIH MHC Inbred minipig was used as control. The GalT knock-out/CD46 knock-in (GalT/CD46) transgenic cell lines were established and used as donor cells. The reconstructed GalT/CD46 embryos were surgically transferred into oviduct of naturally cycling surrogate sows (Landrace × Yorkshire) on the second day of standing estrus. Unlike control (1.2 kV/cm,, 75.4%), the fusion rate of the GalT/CD46 donor cells was significantly higher in 1.5 kV/cm, (84.5%) than that of 1.25 kV/cm, (20.2%) (p<0.01). When the number of the transferred embryos were more than 129, the pregnancy and delivery rates were increased to 13/20 (65%) and 5/20 (25%) compared to less than 100 group [1/6 (16.7%) and 0/6 (0%)], respectively. To analyze the effect of donor cell culture condition on pregnancy and delivery rates, the GalT/CD46 donor cells were cultured with DMEM or serum reduced medium. In serum reduced medium group, the pregnancy and delivery rates were improved to 8/12 (66.7%) and 5/12 (41.7%) compared to DMEM group [3/7 (42.9%) and 0/7 (0%)], respectively. In conclusion, it can be postulated that an appropriate fusion condition and culture system is essential factors to increase the efficiency of the production of transgenic cloned piglets.

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

Although several enteric viral pathogens including the porcine groups A, B and C rotaviruses (PGARV, PGBRV, and PGCRV), sapovirus (PSaV), and torovirus (PToV) are known to cause endemic diarrheas in weaning and post-weaning piglets, their precise prevalence in Korea is not clear. Therefore, we examined 1,222 diarrhea stools obtained from 627 farms during 2004～2009 by RT-PCR and/or nested PCR for evaluating their precise prevalence in Korea. PGARV was the predominant pathogen during 2004～2007 but its prevalence was markedly reduced during 2008～2009. PGBRV infections caused endemic diarrhea during 2004～2007, but was hardly detected during 2008-2009. PGCRV was detected at 27.0%, 14.5%, 42.4%, 28.8%, 7.3%, and 54.2% during each year of 2004～2009, respectively, indicating its high prevalence in Korea throughout the years. PSaV induced with high prevalence (32.4-39.2%) during 2004～2005 but its detection rate was markedly decreased during 2006～2009. PToV caused sporadic infections only during 2006 (1.0%) and 2007 (6.9%). These enteric viruses were detected in diarrhea specimens in piglets usually in combination with each other and/or together with bacterial pathogens including the Escherichia coli, Salmonella spp., Brachispira hyodysenteriae, and Lawsonia intracellularis. Infections with PGARV, PGCRV, PSaV, and PToV were more prevalent in fecal samples collected in cold seasons. These results provide important epidemiological data for the control and establishment of a surveillance system for the prevailing enteric viruses in Korea.