Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 23, 1999
Publication Date: June 19, 1999
Citation: Lunstra, D.D., Wise, T.H., Ford, J.J. 1999. Changes in testicular structure, daily sperm production (DSP) and Sertoli cell numbers during compensatory hypertrophy in boars hemicastrated at different ages [abstract]. Biology of Reproduction. 60 (Supplement 1):258. (Abstract #531) Technical Abstract: To study compensatory testicular hypertrophy in the boar, 132 male piglets (1/2 Meishan x 1/2 White Composite) were assigned to be hemicastrated (H) at one of five postnatal ages (~26 boars/group): d1, 10, 55, 110 and 220. Remaining testis was removed at 220 d of age in all H boars. Boars were stratified by d220 testis weight, and the highest and lowest 1/4 classified into Large (Lg) or Small testis (Sm) subgroups and assessed for testicular structure (~6 boars/subgroup/H group). In all H groups at 220 d of age, Lg testis boars had 3-fold larger testis (P<.01), higher DSP/g (P<.04), higher (P<.001) volume % of the testis (vol%) occupied by seminiferous tubules, lower (P<.001) vol% Leydig cells, and higher total number of Leydig (P<.02) and Sertoli (P<.001) cells/testis than did Sm testis boars. In Lg testis boars, testis weight was 153%, 136%, 123% and 119%, total DSP was 132%, 144%, 107% and 106%, Leydig cell numbers were 186%, 175%, 161% and 124%, and Sertoli cell numbers were 110%, 110%, 108% and 99% in boars hemicastrated on d1, 10, 55 and 110, respectively, compared to d220 controls. Hypertrophic increases of similar magnitude, albeit numerically different, were observed within respective H groups in Sm testis boars. Thus, testicular hypertrophy in the boar occurs primarily via increased Leydig cell numbers and increased Sertoli cell size. The limited proliferation in Sertoli cells that occurred postnatally implies that most Sertoli cell proliferation occurs prenatally in the boar.