Reproduction Abstracts

One of the most frequently isolated bacteria in porcine semen was Escherichia coli. Overgrowth by contaminant bacteria such as E. coli has a deleterious effect on semen quality and longevity. The objective of this study was to determine the effects of E. coli isolated from porcine semen on sperm motility, viability, semen pH, and field fertility in sow. Semen samples were prepared using BTS extender that did not contain antibiotics. E. coli was isolated from fresh porcine semen collected at dedicated boar studs. It was hemolytic and enteroaggregative E. coli heat-stable enterotoxin 1 (EAST-1)-positive. Three different levels of E. coli were artificially innoculated to semen with following concentrations; control (0), T1 (500 cfu/ml), T2 (5000 cfu/ml), and T3 (50 000 cfu/ml). Semen samples were preserved at 17 °C for 5 days in semen storage box until analyzed. Sperm motility were significantly decreased (P<0.05) on day 3 in T2 compared to control groups. The percentage of viable spermatozoa was significantly decreased (P<0.05) in all groups from day 3. Sample pH was maintained 7.0–7.2 in all groups during the experimental period. To evaluate the field fertility outcomes in bacteria contamination semen, we performed artificial insemination (AI) with 56 herds of weaned Duroc sows. Semen was stored at 17 °C for 3 days before AI. The pregnancy rate and litter size tend to decrease by increasing the concentration of E. coli in semen. In particular, the rate of pregnancy was lower in T3 (58.3%) compare to the other groups (81.8, 75.0, and 76.5%). These results suggest that E. coli contamination has a concentration-dependent detrimental effect on extended porcine semen quality.