Conjugated linoleic acid (CLA) is known for its multiple benefits including improvement of
growth, increasing lean mass, and anti-carcinogenic effects. However, when used in longterm supplementations CLA does not improve semen parameters in boar and bull and
reduces fertility in Japanese quails. The content of unsaturated fatty acids in dietary lipids
plays a significant role in spermatogenesis owning the high proportion of unsaturated fatty
acids in plasma membrane of sperms. Whether CLA plays a role in testicular tissue and epididymal fat is still unknown. Therefore, in this study we hypothesize that long-term supplementation of equal proportion of CLA isomer mix (c9,t11-CLA and t10,c12- CLA) in rabbit
bucks might alter male reproductive potentials. Twelve V-Line weaned male rabbits were
used in 26 weeks trial, rabbits were individually raised and randomly allocated into three dietary groups. Control group (CON) received a basal diet, a group received 0.5% CLA (CLA
0.5%), and a group received 1% CLA (CLA 1%). Rabbits were euthanized at the end of the
trial and several parameters were evaluated related to growth, semen quality, and testicular
and epididymal tissue histopathology and transcriptome. The long-term supplementation of
CLA increased feed intake by 5% and body weight by 2–3%. CLA 1% decreased sperm progressive motility. In testicular tissue L-carnitine and α-tocopherol were decreased by CLA
supplementation. In epididymal fat, CLA tended to decrease concentration of polyunsaturated fatty acids, the expression of SCD5 gene was upregulated by CLA 1% and CASP3
gene was upregulated by CLA 0.5%. Transcription of PPARG was downregulated by CLA.
Feeding 1% CLA also decreased testicular epithelial thickness. Long-term supplementationof CLA modestly enhanced male rabbit growth, but negatively impacted male reproduction,
especially at high dose of CLA. |
