Natural Pig Plasma Immunoglobulins Have Anti-Bacterial Effects: Potential for Use as Feed Supplement for Treatment of Intestinal Infections in Pigs

Hedegaard, Chris J.; Strube, Mikael L.; Hansen, Marie B.; Lindved, Bodil K.; Lihme, Allan; Boye, Mette; Heegaard, Peter M. H.

E. coli and S. diarizonae colonies were retrieved from blood plates and used for inoculating brain-heart broth (agar and media purchased at BD Biosciences, Albertslund, Denmark) cultures incubated overnight with shaking at 37°C. For staining bacteria with Syto24 (Life Technologies), the culture medium was changed to deionised water diluting the cells to OD 546 0.16 and Syto24 was added to a final concentration of 6.5 μM. After 30 min., bacteria were centrifuged at 4500 rpm for 5 min. at 4°C (SL40R, Thermo Scientific, Holm & Halby, Brøndby, Denmark) and thereafter washed twice in 4°C deionised water and then twice in 4°C adhesion buffer (12.5 mM HEPES, 141 mM NaCl, 0.5 mM MgCl 2 , 0.15 mM CaCl 2 , 0.1% gelatine (all purchased at Sigma-Aldrich); pH 7.4).