Ts. Koynarski, L. Sotirov
Abstract. The aim of the investigation was to determine the influence of the C3 component of the complement system on the levels of blood serum lysozyme and the alternative pathway of complement activity (APCA) in sheep. The experiment was carried out with sheep and rams belonging to nine sheep breeds – Mouton Charollais, Ile de France, Trakia Merino, Dairy crosses, White Maritsa, Patch-faced Maritsa, Karnobat, Pleven Blackhead and Local Stara Zagora. For more accurate results we tested equal number of animals from each breed (48), the total number of samples was 432. The two allelic genes (C3S and C3F) formed nine C3 genotypes–SS, SS1, FF, FS, FS5, FS7, FS10, FF1, and F1F1 with different prevalence between the breeds. It was found out that the C3 genotypes do not impact significantly the levels of serum lysozyme concentrations and APCA, therefore indirect selection after this gene marker will not improve the levels of innate immune response in sheep.