Vaccination against follistatin affects reproductive potential in cycling gilts

Abstract

Primiparous sows (gilts) were actively vaccinated against follistatin in an attempt to modify litter size. Forty-seven gilts were vaccinated four times against a recombinant porcine follistatin (FS) or a sham vaccine (CTL) and were allowed to mature naturally prior to breeding. At breeding, FS antibody titers ranged from 0 to 1:6400 in the FS vaccinated gilts, and were not detectable in the CTL gilts. Overall, follistatin vaccination did not affect the total number of pigs born live (FS = 10.9 ± 0.5, CTL = 10.3 ± 0.4), stillborn (FS = 0.4 ± 0.1, CTL = 0.4 ± 0.2) or mummified (FS = 0.1 ± 0.1, CTL = 0.3 ± 0.1). However, separation of the FS vaccinated gilts into low (≤1:400, n = 16) and high (>1:400, n = 7) titer groups revealed significant differences in piglets born alive (FS high titer = 12.9 ± 0.9, FS low titer = 10.0 ± 0.5: P = 0.01) and total number of piglets born (FS high titer = 13.0 ± 0.8, FS low titer = 10.8 ± 0.6: P = 0.08). This study shows that vaccination of gilts against follistatin increased litter size in those gilts which achieved a high antibody titer to follistatin. Key words: Swine, follistatin, immunoneutralization, fecundity, litter size