Raising Chilled Ram Sperm Quality with NMN
Introduction
Artificial insemination with chilled ram semen is commonly used method in livestock industry. But storing sperm in chilled conditions may cause changes in sperm membrane function and structure, and shortens its lifespan. Notably, supplementation of β-nicotinamide mononucleotide (NMN) can raise ram sperm quality during storage at 4°C.Merits of artificial insemination with chilled ram semen
The adoption of artificial insemination with chilled ram semen can ensure good breeding stock and accelerate the reproduction. By this way, the risk of diseases such as vibriosis, trichomoniasis, vaginitis, leptospirosis and brucellosis, which are transmitted by rams in natural breeding, can be reduced to a large extent. In addition, this method allows crossbreeding or purebreeding, and reduces the number of rams to be bred, which is beneficial and cost-effective. Importantly, this method can greatly avoid the risk of dystocia or injury due to the big size difference between rams and ewes during breeding. Chilled semen can be preserved semi-permanently to send far away, avoiding the trouble of transporting or moving breeding animals.The beneficial role of NMN in improving ram sperm quality
Supplementation of NMN markedly improves the sperm motility, as evidenced by the obvious increases in the motility parameters such as total motility, progressive motility, straight-line velocity (VSL), average path velocity (VAP), linearity (LIN), curvilinear velocity (VCL), and straightness (STR).Meanwhile, NMN maintains the plasma membrane integrity and acrosome integrity.
Note:
(Figure A) White arrow: viable sperm with intact acrosome; green arrow: viable sperm with damaged acrosome; orange arrow: dead sperm with damaged acrosome; black arrow: dead sperm with intact acrosome
(Figure B) White arrow: sperm with an intact plasma membrane; orange arrow: sperm with a damaged plasma membrane
What’s more, NMN elevates the mitochondrial activity and antioxidant capacity, while reducing the sperm oxidative stress and apoptosis, as manifested by the downregulation of Cleaved-Caspase 3, Cleaved-Caspase 9, Bax, LPO, MDA, and ROS, as well as upregulation of Bcl-2, GSH and SOD in sperm.