Influence of date palm pollen grain extract on rabbit buck semen characteristics throughout chilled storage period of 72 h

Background
The demand for using stored semen in artificial insemination programs of livestock animals is increasing. Therefore, developing and improving methods for semen preservation would provide adequate fertility rates that maintain the high production rates for rabbit industry. Several studies on preservation protocols and extender composition have been carried out.
Objective
The current study was designed to examine the effect of various concentrations of date palm pollen grain extract (DPPE) on postchilling quality of rabbit semen.
Materials and methods
Total phenolic and flavonoid substances and antioxidant activity were assessed in DPPE. High-performance liquid chromatography was used for identification and separation of goal metabolites. Semen was gathered from 10 male rabbits, grouped, and then split into five fractions (500 μl each). The first fraction represented as control, whereas DPPE was supplemented at concentrations of 1.6, 2.0, 2.4, and 2.8 mg/5 ml tris-citric extender. Extended semen specimens were cooled at 4°C for 72 h. Motile, life, abnormal, membrane, and acrosome integrity percentages of sperms were appraised in chilled semen all over the refrigeration period.
Results and conclusion
Total phenolic and total flavonoids contents in the DPPE were 4.15 mg GAE/g extract and 0.74 mg CE/g extract, respectively. The DPPE specimen showed various antiradical activity gauged toward 2,2-azino-bis/3-ethil-benothiazoline-6-sulfonic acid (12.37 mM TE/g) and 2,2-Diphenyl-1-picryl-hydrazyl (4.06 mM TE/g). However, the reducing capacity assessed by ferric reducing activity power method was 9.19 mM TE/g/g. The most effective compounds in the DPPE were pyrogallol (4150.92 μg/g extract), ferulic acid (2935.50 μg/g extract), and rutin (2163.99 μg/g extract). The enrichment of semen extenders with 2.4 mg DPPE/5 ml tris-citric extender had preserved the sperm forward motility, sperm livability, sperm acrosome integrities, and sperm membrane integrities in an upright state during cooling till 72 h related to control treating. No adverse effects were recorded on sperm abnormalities. It could be concluded that the enriching of rabbit bucks’ semen tris-basic extender by 2.4 mg DPPE/5 ml tris-extender (the perfect and harmless concentration) sustained the sperm features in decent conditions all over a cooling period of 72 h.