Lactoferrin from bovine milk inhibits bovine herpesvirus 1 in cell culture but suppresses development of in vitro-produced bovine embryos

Bovine herpesvirus 1 (BoHV-1) is widely distributed among cattle populations and has been associated with cells, fluids, and tissues collected from donor animals for use in reproductive technologies. The purpose of this study was to determine if lactoferrin would inhibit BoHV-1 in cell culture and to evaluate if embryos could develop normally when cultured in vitro with lactoferrin. In Experiment 1, lactoferrin (10 mg/mL) inhibited up to 25,000 plaque forming units (PFU)/mL of BoHV-1 in Madin Darby bovine kidney (MDBK) cell culture. In Experiment 2, lactoferrin (10 mg/mL) combined with cidofovir (62.5 μg/mL) inhibited up to 100,200 PFU/mL of virus in cell culture. In Experiment 3, following fertilization, presumptive zygotes were cultured in media containing lactoferrin (10, 5, and 2.5 mg/mL). Embryonic development and quality were assessed, and embryonic viability was determined by counting the nucleated cells of developed blastocysts. While lactoferrin did not affect the nucleated cell count of the treated embryos, it did significantly decrease blastocyst development. In conclusion, lactoferrin from bovine milk can inhibit BoHV-1 in cell culture. However, supplementation of in vitro culture medium with lactoferrin inhibits blastocyst development of in vitro-produced embryos.