title: Growth of testes and testicular morphology after eight generations of selection for increased predicted weight of testes at 150 days of age in boars.
abstract: Weights of testes and epididymides, body weight, and morphometric measurements of testicular tissue of 75 boars of a line selected for eight generations for predicted weight of testes at 150 d of age and 75 boars of a randomly selected control line were used to evaluate the effects of selection on testicular development at 70, 100, 130, 160, and 450 d of age (n = 15 boars per line per age). Body weights for boars of the select and control line did not differ (P < .05) and the shape of the body growth curve was similar for both lines. Boars of the select line had larger testes than control boars at each age (P < .05), but there was a significant line x age interaction. The percentage increase of the select line mean over the control mean for weight of testes was 37% at 70 d, a maximum of 120% at 100 d, and 25% at 450 d. The percentage of the testes made up of seminiferous tubules differed between lines (P < .01). Lines had similar means of approximately 28% at 70 d and 71% at 450 d, but the mean for the select line was larger between 100 and 160 d of age; the greatest difference was 11.6% (control = 43.7, select = 55.3%) at 100 d. After 70 d of age, select-line boars had a greater percentage of seminiferous tubules with lumens that contained elongated spermatids (P < .10).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Harder
authors.forename: D D
authors.initials: DD
authors.lastname: Lunstra
authors.forename: R K
authors.initials: RK
authors.lastname: Johnson
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001835:Body Weight / Q000235:genetics / Q000502:physiology; D001947:Breeding; D004822:Epididymis / Q000254:growth & development; D007985:Leydig Cells / Q000166:cytology; D008297:Male; D009929:Organ Size / Q000235:genetics / Q000502:physiology; D011237:Predictive Value of Tests; D012641:Selection, Genetic; D012671:Seminiferous Tubules / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D012741:Sexual Maturation / Q000502:physiology; D013087:Spermatids / Q000166:cytology; D013552:Swine / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development*; D013737:Testis / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development*