Natural honey as cryoprotectant on spermatozoa quality of boar semen

Abstract

Natural honey has been used as cryoprotectant prior to cryopreservation of spermatozoa quality of boar semen. The aim of this study was to evaluate the effects of inclusion level of natural honey supplemented in commercial boar semen VIM® extender on fresh boar semen liquid preservation quality at 20oC up to 3-days interval. Semen samples from 2-yr-old Largewhite boar were collected using bare-hand technique. Collected samples were freshly evaluated physically and microscopically before being divided and diluted with commercial boar semen extenders as control and three different concentrations of natural honey extenders (0.5%NH, 1.0%NH, 2.0%NH, respectively). Samples were prepared by volume per volume (v/v) of natural honey, respectively. The processed semen was then stored at 20oC for 3 h before assessment of quality. Semen samples from each treatment were then assessed for sperm progressive motility, sperm viability and sperm morphology through microscopic observation and eosin-nigrosin staining procedure. The study revealed that addition of 0.5%NH in commercial extenders across 3-days intervals were significantly higher (p<0.05) as compared to 1%NH and 2%NH which can preserve sperm motility and viability up to 24 hours. However, addition of different concentrations of natural honey were not significantly (p>0.05) affected by sperm abnormalities which maintain the sperm morphology. Our findings showed higher concentrations of honey were not suitable and showed significantly poor semen quality following cryopreservation. This demonstrated that, when held at 20°C, sperm diluted in 0.5%NH were the optimal concentration for preservation of boar liquid semen before freezing.