Quantitative information was collected on male reproductive effects of mate
rnal and postnatal dietary exposure to flaxseed (20 or 40%), flaxmeal (13 o
r 26%) or standard NIH AIN-93 feed (0% flaxseed control). Measurements were
made on the testes of Fl generation males rats (1) whose mothers were expo
sed to the diets designated above, and (2) who, after weaning, were placed
on the same diet as their mothers for an additional 70 days. The seminifero
us tubules comprised 86%, 84%, 84%, 84% and 85% of the total testis volume
while the interstitial space comprised 12%, 14%, 14%, 14%, 13% of the total
testis volume for the 0% flaxseed/flaxmeal, 20% flaxseed, 13% flaxmeal, 40
% flaxseed and 26% flaxmeal groups, respectively. Statistically significant
decreases in the absolute volume of the seminiferous tubules were observed
in the 20% and 40% flaxseed-treated groups when these groups were compared
to controls. Borderline statistically significant differences were also ob
served when Sertoli cell nucleolar number per tubular cross-section were co
mpared in the 13% flaxmeal and 20% flaxseed treatment groups. These effects
were not considered biologically significant because other parameters of m
ale reproductive function appeared normal, Overall, the quantitative inform
ation obtained suggests that exposure to flaxseed/flaxmeal at the doses use
d in the present study does not adversely affect testis structure or sperma
togenesis in the rat. Published by Elsevier Science Ltd.