14th Annual Conference of the European Society for Domestic Animal Reproduction
[en] Pregnancy-associated glycoprotein ; sheep ; Western blot
[en] This study prospected whether Western blot analysis could be an alternative to radio-immunoassay (RIA) for sheep pregnancy diagnosis. Blood samples were taken from Boujaâd ewes (n= 9) and Boujaâd x D’man (BD) cross breed (n= 12). The pregnancy associated glycoproeins (PAGs) were weekly monitored in plasma during the whole gestation and the first month postpartum by two RIA systems (El Amiri et al., 2007, Reprod Domest Anim 42:257-62). The highly immunoreactive samples derived from PAG profiles were tested using Western blot based on the same antiserum used in RIA. Each week (from the 13th to the 19th week), two pools of plasma samples (4 ml each) were taken from single and multiple lambing ewes respectively. Samples were submitted to a protein extraction at neutral pH, followed by ammonium sulfate (A.S.) precipitation, dialysis, and lyophilization. The placental extract was used as a check. Results revealed that ewes with multiple lambs presented numerically higher PAG concentrations. In both RIA systems, the high concentrations were recoded around the 19th week of gestation and the maximal concentrations varied from 120 to 700 ng/ml. In Western blot, the placental extracts reacted positively while the plasma samples did not give any positive reaction. In conclusion, the RIA remains the only sensitive method to measure PAGs in plasma. The present study strengthens the need to develop an ELISA kit as an alternative to RIA systems.