Fig 1. Cumulative population doublings of immortalized and primary chicken preadipocytes.

Immortalized chicken preadipocytes (ICP1, ICP2) and two batches of primary chicken preadipocytes (PCP1, PCP2) were serially subcultured for more than 1 year. Both ICP1 and ICP2 cell lines grew beyond PD 100. The PCP1 and PCP2 cells were no longer capable of reaching confluence by PD 9. The cumulative PDs of ICP2 were calculated from 95 days (after two rounds of retrovirus infection and drug selection).