Eighteen sexually mature Hy-Plus rabbit bucks of nine months old were used in the present study. The study was designed to evaluate grade and percentages of progressive sperm motility, in addition to percentages of spermatozoa with swollen heads or coiled tails of diluted semen supplemented with different levels of Doum aqua's extract as responded to hypo-osmotic solution, during incubation at 37 oC for up to 60 minutes. Semen was collected artificially and samples showing sperm motility less than 70% were removed. Accepted semen samples were pooled and divided into two parts. The first part was diluted at 300 mOsm/ L (normal osmolarity) while the other was diluted at 100 mOsm/L (hypo-osmotic pressure). Each part of diluted semen was subdivided into four parts. The 1st group was kept untreated as a control, and Doum aqua's extract were added to 2nd, 3rd and 4th groups at concentrations of 1, 2 or 3 ml/ 100 ml diluted semen, respectively.
Results obtained indicated that, sperm motility in solutions with different osmolarities (300 or 100 mOsm/L) were significantly (P ≤ 0.01) high, while the percentages of spermatozoa with coiled tails or swollen heads were significantly (P ≤ 0.01) lower at level of 300 mOsm/L (normal osmolarity) than 100 mOsm/L (osmotic stress), during incubation at 37 oC for up to 60 minutes in rabbit semen groups.
Advancement of incubation time up to 60 minutes of diluted rabbit semen in solutions with different osmolarities significantly (P ≤ 0.01) decreased grade of sperm motility and increased advanced sperm motility percentage spermatozoa with swollen heads and coiled tails, respectively. Progressive sperm grades and percentages and percentages of spermatozoa with swollen heads or coiled tails in both osmolarities used were significantly (P ≤ 0.01) arranged in descending order as recorded by diluted semen added with 3, 2, 1 and 0 mg Doum aqua's extract/ 100 ml diluted semen, respectively. Adding 3 ml Doum aqua's extract/ 100 ml diluted semen insignificantly increased grade and percentages of sperm motility and spermatozoa with swollen heads, compared with 2 ml of the extract.
Conclusively, it could be concluded that, adding diluted rabbit semen with aqua's extract of Doum improved semen quality, and prolonged spermatozoa storagability, during semen conservation at incubation condition.