Feel I've enough sources & data to venture an answer on this one myself now
Step one : Can we produce the pig in the first place.
Induction of donor-specific tolerance to cardiac xenografts in utero: 1998 Sep
"xenotransplantation may be possible by induction of donor-specific tolerance in utero"
IMMUNO-INTERVENTION FOR THE ...
Erythrocytes need more than just glucose in order to function and, they also need a extracelullar medium who shares the same osmolarity, so placing your red blood cells into a medium that solely has glucose will be problematic. If you solely want to evaluate the lactic fermentation carried out by erythrocytes on a short period of time, then you can add the ...
They need glucose, they absorb that from dissolved particles in water (the plasma). So if you isolate the cells, you'd have to put them in a medium with sugar and so on. It would be analogous to the medium they exist in before you centrifuge them, I think.