Association of [formula omitted] serover [formula omitted] type hardjobovis with bovine ova and embryos produced by in vitro fertilization

Abstract

The association of Leptospira borgpetersenii serovar hardjo type hardjobovis with in vitro fertilized (IVF) embryos was investigated in in vivo and in vitro. The organism could not be isolated from IVF embryos that were generated from ova harvested from experimentally infected donor heifers and cultured in commercial INRA Henezo B2 medium containing low levels of penicillin and streptomycin. Recipient heifers (n = 14) to which embryos cultured in Menezo B2 medium were transferred, did not develop antibody titres to Leptospira , and this organism was not isolated from the resulting fetuses (n = 5). Similarly, the organism could not be isolated from IVF embryos that were produced from in vitro-exposed oocytes to Leptospira and cultured in Menezo B2 medium, or TCM-199 medium supplemented with penicillin and streptomycin. In contrast, leptospires were isolated from IVF embryos that were produced from in vitro- exposed oocytes and cultured in TCM-199 medium free of antibiotics. The sequential washing procedure that was used with media free of antibiotics did not render infected embryos free of the pathogenic microorganism. Oocytes exposed to Leptospira in vitro were not transferred into the recipients. The presence of serovar hardio in the IVF system had no detrimental effect on fertilization rates or on embryonic development to the blastocyst stage. This study shows that it is possible to obtain transferable stage embryos from oocytes recovered from infected donors and from oocytes exposed in vitro to Leptospira . Such embryos may be associated with the microorganism, and the use of culture media supplemented with antibiotics for processing IVF embryos would be advisable in order to prevent any risk of transmission.