Production of interferon by red deer (Cervus elaphus) conceptuses and the effects of roIFN-tau on the timing of luteolysis and the success of asynchronous embryo transfer

Abstract

The role of interferon in early pregnancy in red deer was investigated by (a) measuring production of interferon by the conceptus, (b) testing the anti-luteolytic effect of recombinant interferon-tau in non-pregnant hinds, and (c) treatment of hinds with interferon after asynchronous embryo transfer. Blastocysts were collected from 34 hinds by uterine flushing 14 (n = 2), 16 (n = 2), 18 (n = 8), 20 (n = 13) or 22 (n = 9) days after synchronization of oestrus with progesterone withdrawal. Interferon anti-viral activity was detectable in uterine flushings from day 16 to day 22, and increased with duration of gestation (P < 0.01) and developmental stage (P < 0.01). When interferon-tau was administered daily between day 14 and day 20 to non-pregnant hinds to mimic natural blastocyst production, luteolysis was delayed by a dose of 0.2 mg day(-1) (27.3 +/- 1.3 days after synchronization, n = 4 versus 21 +/- 0 days in control hinds, n = 3; P < 0.05). Interferon-tau was administered to hinds after asynchronous embryo transfer to determine whether it protects the conceptus against early pregnancy loss. Embryos (n = 24) collected on day 6 from naturally mated, superovulated donors (n = 15) were transferred into synchronized recipients on day 10 or day 11. Interferon-tau treatment (0.2 mg daily from day 14 to 20) increased calving rate from 0 to 64% in all recipients (0/11 versus 7/11, P < 0.005), and from 0 to 67% in day 10 recipients (0/8 versus 6/9, P < 0.01). The increased success rate of asynchronous embryo transfer after interferon-tau treatment in cervids may be of benefit where mismatched embryo-maternal signalling leads to failure in the establishment of pregnancy.

Reproductive biotechnologies for endangered mammalian species

“…Successful interspecific-bispecific transfers (Spanish ibex embryos (Capra pyrenaica) + goat embryos) into the domestic goat have also been reported [18]. Even if treatment with interferon could reduce embryonic loss due to asynchrony between the embryo and the recipient mother [15], the immunological barrier remains a major restriction for interspecific pregnancies. In deer species, common related subspecies are easier to find.…”

“…In wild species, scarce knowledge on the kinetics of embryo development and foeto-maternal recognition may lead to asynchrony between the transferred embryo and the recipient mother. In a recent study on the red deer, treatment of the recipient mother with interferon reduced significantly embryonic loss after asynchronous transfer [15]. For endangered wild species, cryopreservation of embryos remains to be developed.…”

<b>Interferon-tau Polymorphisms and Their Potential Functions in Ruminants</b>

“…Different mechanisms are used to prevent CL regression in various species. In cattle, sheep, goats, red deer and potentially all related pecoran ruminants (antelope, musk ox, giraffe), a conceptus-derived factor now known as interferon-tau (IFN-ô) is responsible for extending the functional lifespan of the CL (Demmers et al, 2000;Ealy et al, 1998b;Homeida & al Afaleq, 1994;Kiesling et al, 2000;Meyer et al, 1995).…”