Immediately
after collection with heparin, each blood sample (approximately
5 mL) was centrifuged at 3,000 × g for 10 min at
4°C to obtain plasma, which was stored at -20°C until analysis.
At 94, 95, or 97 d of age (4 to 6 pigs in each line per
day), the littermates were killed by jugular exsanguination
after electronarcosis, and then digestive, urogenital, and respiratory
tracts were removed.