The effect of dietary Se and vitamin E on the onset
of spermatogenesis at the various ages is presented in
Table 2. At 5.4 mo of age, boars fed supplemental vitamin
E or Se had a higher percentage of seminiferous
tubules undergoing spermatogenesis, but only the response
to dietary vitamin E was significant (P < .05).
By 6.2 mo of age, all tubules were undergoing active
spermatogenesis, but there was no effect from dietary
Se or vitamin E (P > .15). Boars supplemented with Se,
however, had seminiferous tubules with wider diameters
(P < .05) at 6.2 mo of age; Se had no effect at 18
mo of age. Sexual activity or inactivity at 18 mo of age
or dietary vitamin E supplementation did not affect
diameter of the seminiferous tubules (P > .15).