The effectiveness of recombinant Ol fusion protein (Ovalbumin-LHRH-7) in supressing reproductive functions when injected in single-dose vaccination protocols with different adjuvants

Abstract

The objective of this study was to evaluate the effectiveness of recombinant LHRH fusion protein,Ovalbumin-LHRH-7(OL),using a single-dose vaccination protocol in combination with different adjuvants in suppressing reproductive functions in buck kids.For this pur-pose, either a mixture of free OL antigen and encapsulated OL antigen, or encapsulated OL antigen was used. Thirty-nine native buck kids at 12 weeks of age were divided into control (n=7) and treatment groups (n=8 bucks/group).The four treatment groups were formed according to the different vaccine formulations: Group Cp Greceived0.5mgfree OL protein to get her with 1. 0 mg of encapsulated protein with CpG adjuvant. Group mFCA received 0.5mg free OL protein together with 1.0 mg of encapsulated protein with modified Fre-und’s complete adjuvant. Group IS received 1.5 mg encapsulated OL protein with amix of inulin and saponin adjuvants. Group Ism FCA received 1.5mg encapsulated OL protein withamixofinulin, saponin and modified Freund’scomplete adjuvants. Scrotal circumference in CpG and mFCA groups were significantly smaller than that of Control, IS and ISm FCA groups (P<0.05). Numbers and percentage of bucks having spermatozoa in their ejaculate were significantly lowerin Cp G and mFCA groups (P<0.05). OL immunization completely suppressed sperm production, exceptone buck,in CpG and FCA groups (P<0.05).These results imply that it is possible to use OL protein in a single injection protocol for the purpose of immunocastration. Further investigation with a larger number of animals should be carried out to determine the longevity of response to a single injection.