Prokaryotic Expression and Active Immunisation against Recombinant-Derived Prolactin Fusion Protein on Broodiness and Egg-Laying in Wanxi-White Goose

This experiment aims to produce a recombinant prolactin (rPRL) for use in immunising Wanxi-white goose and to determine the immunisation effects on broodiness and egg production. A stable prokaryotic expression system with rPRL obtained extra-cellularly was established. Wanxi-white geese (n = 100) performed broodiness were randomly divided into five groups (20 per group): group I was injected with saline as negative control, group II was orally administered with Bromocriptine as positive control, groups III, IV and V were subcutaneously injected with either 1, 2 or 4 mg·mL−1 rPRL, respectively. This process (FA-I) was repeated after interval of 10 days (SA-I). After FA-I, broodiness significantly decreased in groups III, IV and V compared to group I ( P < 0.01), while egg production showed no significant difference among groups. After SA-I, broodiness in group IV and V was significantly lower than that of other groups ( P < 0.05), and egg production percentage in group IV showed significantly higher than that of group III ( P < 0.05), but only numerically higher than that of other groups. Broodiness showed no difference among groups 10 days after SA-I, but broodiness was significantly increased to more than 20% in all groups. Serum prolactin concentrations showed high secretion in geese under broodiness and decreased in geese that wake up from broodiness after SA-I. In conclusion, active immunisation with rPRL decreased broodiness and increased egg production in Wanxi-white geese. However, the immune period was short, and the performance was significantly affected by environmental factors.