The objective of this study was to determine the effects of E. coli on boar sperm quality and reproductive performance in sows after artificial insemination. Three different levels of E. coli were artificially inoculated to semen with following concentrations; Control, 500, 5,000 and 50,000 colony forming unit (cfu)/ml. Semen samples were preserved at 17℃ for 5 days. Sperm motility was significantly decreased (p<0.05) on day 3 in the group inoculated with 5,000cfu/ml compared to control groups. In all treatment groups, sperm motility was gradually decreased as storage time increased, but the decline pattern was more drastic in the groups inoculated with 5,000 and 50,000 cfu/ml groups from day 3 (p<0.05) compared to control group. After 3 day of storage at 17℃, sperm viability in sample inoculated with the highest concentration (50,000 cfu/ml) of bacteria was less (p<0.05) than that of control group. The pH of semen sample pH was maintained 7.2～7.5 in all groups during the experimental period. No differences (p>0.05) were found for both storage time and bacterial concentration. The pregnancy rate and live born piglets tend to decrease by increasing the concentration of E. coli in semen. In particular, the rate of pregnancy was lower in the group inoculated with 50,000 cfu/ml (58.3%) compare to the other groups (81.8, 75.0, 76.5%). These results suggest that the contamination of E. coli in boar semen negatively affects fertilizing ability of boar sperm and the reproductive performance obtained from sows after artificial insemination.

본 연구는 식물성 불포화지방산 복합제로 이루어진 보조사료를 첨가하여 이유자돈의 균일성과 증체성적에 미치는 효과를 구명하기 위하여 수행하였다. 공시동물은 일반 종돈장의 Landrace 모돈 110두와 포유자돈 248두를 공시하였다. 시험구는 모돈시험에서는 장쇄지방산 복합제제를 분만사입식부터 이유시까지 약 4주간 급여하였고 자돈시험에서는 액상 중쇄지방산 complex를 포유기간 중 2회 구강투여 하였다. 모돈 시험에서 복당생존자돈수와 복당생시체중은 처리구간 차이를 보이지 않았으나, 복당이유자돈수와 복당이유체중에서는 시험구가 대조구에 비해 유의적으로 높았다(P<0.01). 모돈의 사료섭취량은 시험구가 유의적으로 높았으며, 발정재귀일령은 유의적으로 차이는 없었으나 시험구에서 평균 0.3일 정도 빠르게 나타났다. 포유기간내 일당증체량 역시 이유체중과 양의 상관관계를 갖고 있어 유의적인 차이가 있는 것으로 나타났다. 자돈시험 결과 시험구는 포유기간내 이유체중이 대조구에 비해 유의적으로 높았으며 생시체중 대비 증체량도 같은 기간에 많은 차이를 나타내었다. 자돈의 이유체중에 대한 변이의 지표를 보면 시험구와 대조구간 변이의 차이는 없는 것으로 나타나 개체간의 균일성에 대해서는 처리간차이는 나타나지 않았다. 결론적으로 포유기의 장쇄지방산 급여는 모돈의 젖에서 올레인산, 리놀산 등불포화지방산의 함량을 증가시키고, 젖 분비량과 사료섭취량을 증가시켜 자돈의 초기증체에 기여하는 것으로 나타났고, 자돈에 대한 중쇄지방산의 급여도 이유체중을 증가시키는 효과를 가져왔다.

This study was undertaken to evaluate the relationship between in vitro maturation and plasminogen activators (PAs) activity on porcine cumulus-oocytes complexes (COCs) exposed to oxidative stress. When COCs were cultured in maturation medium with hydrogen peroxide (H2O2), the proportion of the germinal vesicle breakdown (GVBD) and oocytes maturation were decreased with addition of H2O2, and were significantly (p<0.05) lower in medium with 0.1 mM H2O2 than control group. Also, the rate of degenerated oocytes was increased in as H2O2 concentration increased. When COCs were cultured for 48 h, three plasminogen-dependent lytic bands were observed: tissue-type PA (tPA); urokinase-type PA (uPA); and tPA-PA inhibitor (tPA-PAI). PA activity was quantified using SDS-PAGE and zymography. When H2O2 concentration was increased, tPA and tPA-PAI activities also increased in porcine oocytes cultured for 48 h, but not uPA. In other experiment, embryos were divided into three groups and cultured in (1) control medium, (2) control medium with 1.0 mM H2O2 and (3) control medium with 1.0 mM H2O2 along with catalase in concentrations of 0.01, 0.1, and 1.0 mg/ml, respectively. H2O2 decreased the rate of GVBD and maturation in porcine COCs but catalase revealed protective activity against oxidative stress caused by H2O2. In this experiment, tPA and tPA-PAI activities were higher in media with 1.0 mM H2O2 alone. Increasing concentration of catalase decreased tPA and tPA-PAI activities in porcine oocytes. These results indicate that the exposure of porcine follicular oocytes to ROS inhibits oocytes maturation to metaphase-II stage and increase the oocytes degeneration. Also, we speculated that increased ROS level may trigger tPA and tPA-PAI activities in porcine oocytes matured in vitro.

The objective of this study was to determine the effect of semen extenders on the motility, viability and fertility in vitro of spermatozoa during storage of fresh boar semen diluted in different commercial extenders used for pig artificial insemination (AI). In this experiment, semen were diluted in Androhep plus, Beltsville Thawing Solution (BTS), Modena, Seminark and Vitasem LD. Five ejaculates were collected from three Duroc boars and sub-samples were diluted (30×106 spermatozoa/ml) in different extenders. Semen was stored at 17℃ for 10 days. Sperm motility and viability was assessed using Computer-Assisted Semen Analysis (CASA) and flow-cytometry on 1, 3, 5 and 10 day post collection. The motility of spermatozoa stored in different extenders was gradually decreased by increasing the duration of storage of semen. However, there was not significantly different in the sperm motility and viability among other extenders. On the other hand, the in vitro-matured oocytes were fertilized and cultured in vitro to assess the fertility of boar spermatozoa stored for 3 and 10 days in different extenders. The percentage of morula and blastocyst were taken as indicators of fertility in vitro of spermatozoa. Therefore, there were no differences in the rate of embryos developed to the molular and blastocyst stage. There were no differences in the motility and fertility in vitro among 5 kinds of commercial boar semen extenders.