DETECTION OF PORCINE CIRCOVIRUS TYPE 2 DNA IN OVARY AND UTERUS FROM GILTS CULLED DUE TO REPRODUCTIVE DISTURBANCE

Abstract

The objectives of present study were 1) to determine the association between porcine circovirus type2 (PCV2) DNA detection in ovary and uterine tissues and reproductive performance, reason for culling, gross morphology, and PCV2 ELISA antibody titer and 2) to locate the PCV2 capsid protein in the ovary and uterus of gilts culled due to reproductive disturbance. In total, formalin-fixed paraffin-embedded ovaries (n=70), uteri (n=102), and serum samples (n=102) were included. Historical data (i.e., body weight, age at enter into the herd, age at culling, average daily gain (ADG)) and reproductive performances (i.e., age at first observed estrus, age at first mating, and non-productive days (NPD)) were collected. Reasons for culling (abortion, abonormal vaginal discharge, anestrus, repeat service, and non-reproductive reason), gross morphology of the ovary (normal, single or multiple cyst, miscellaneous) and the uterus (normal, endometritis, and miscellaneous) were classified. DNA were extracted by using a commercial extraction kit. The polymerase chain reaction was performed by using ORF1 of PCV2 specific primers. The PCV2 capsid protein localization was identified by using polyclonal anti-PCV2 primary-antibody. Serums were test for PCV2 antibody by using the commercial ELISA. It was found that PCV2 DNA were detected in 21/70 (30.0%) of the ovary and in 46/102 (45.1%) of the uterus. Reproductive performances of gilts that had PCV2 DNA in their reproductive organs and those without the PCV2 DNA were not significantly difference. The percentage of PCV2 detection in the uterus in gilts culled due to non-reproductive problem 4/20 (20.0%) was lower than that in gilts culled due to abortion 6/7 (85.0%), abnormal vaginal discharge 19/40 (47.5%), and anestrus 15/28 (53.5%) (p<0.05). The percentage of PCV2 DNA detection in either ovarian or uterine tissues were not related with gross morphologies of both organs. The average PCV2 antibody titer of the gilts were 1,271±867 (range 150 to >2,484). The percentage of PCV2 DNA detection in the gilts with a high antibody titer (23.0%) was lower than that in the gilts with low antibody titer (57.6%) and seronegative gilts (64.5%) (p<0.05). PCV2 capsid proteins were detected in uterine tissues by immunohistochemistry. The PCV2 were appeared both in the cytoplasm and the nucleus of the cells. In addition, the PCV2 antigens intranuclear staining were found in the endometrial cells, while intracytoplasmic and the intranuclear staining were found in the lymphocytes and macrophages. In conclusion, PCV2 was detected by 30.0% of the ovary and 45.1% of the uterus of gilts culled due to reproductive disturbances. The reasons for culling were associated with PCV2 DNA detection. No association between reproductive performance, and gross morphology and PCV2 DNA detection were observed. The PCV2 capsid protein were found in the endometrial cells, subepithelial lymphocytes and macrophages. The PCV2 DNA detection in the ovary of gilts with high positive PCV2 antibody titer were lower than the gilts with lower PCV2 antibody titer.