2.5. Histologic analysis
Testicular pieces from CryoXeno and conventional pigs
were cut into sections of 5-mm thick and stained with hematoxylin
and eosin. The seminiferous tubule crosssections
were sorted into the following categories, as
described previously: [4,13,15] (1) no germ cells present
(tubule cross-sections showing Sertoli cells only); (2)
spermatogonia present; (3) spermatocytes present as the
most advanced germ cells; (4) round spermatids present as
the most advanced germ cells; (5) elongated spermatids
present as the most advanced germ cells; and (6) mature
sperm (spermatozoa) present in the lumina of the tubules