Effects Of Melatonin, Dopamine Hydrochloride And Egg Yolk On Room Temperature Preservation Of Boar Semen

The objective of the present study was to evaluate the effects of melatonin, dopamine hydrochloride and egg yolk on room temperature preservation of boar semen and provide a necessary reference for the popularization and application of the three reagents to artificial insemination in pigs. Samples were respectively collected from eight boars (two Landrace, three Yorkshire and three Duroc), housed at the Guangxi Keda Livestock&Poultry Improvement Co. Ltd, of proven fertility,1.5-2year of age. Only samples with a minimum of80%motile spermatozoa and normal scent/tint were diluted with the extenders [containing melatonin (0,0.01,0.1and1mmol/L), dopamine hydrochloride (0,1,10and100mmol/L), egg yolk (15%,20%and25%) or dual\triple combinations of the optimal concentration of the three chemicals] for room-temperature preservation, and then the diluted semen was preserved at16-18℃. The results show that1)0.01m mol/L melatonin significantly improved motility of extended spermatozoa (P<0.05), and1mmol/L melatonin significantly reduced abnormality of spermatozoa preserved for24h (P<0.05), but there weren’t significant differences in survival effective time, survival overall time, survival index of preserved spermatozoa and acrosomal integrity of spermatozoa preserved for24h between the three treatments and the control (P>0.05)2) motility of spermatozoa extended with100mmol/L dopamine hydrochloride was lower (P<0.05) than the control, and survival effective time, survival overall time and survival index of spermatozoa preserved in1mmol/L dopamine hydrochloride were higher (P<0.05) than the control, but there weren’t significant differences in abnormality and acrosomal integrity of spermatozoa preserved for24h between the four groups (P>0.05)3)20%egg yolk resulted in significant improvement (P<0.05) in motility and survival overall time of extended spermatozoa, but15%or25%egg yolk didn’t demonstrate significant enhance (P>0.05) in the two parameters; significant reduction (P<0.05) of survival effective time of spermatozoa preserved in15%egg yolk was detected, and significant increase (P<0.05) in20%or25%egg yolk was determined; survival index and acrosomal integrity (24h) of spermatozoa preserved in15%egg yolk didn’t significantly vary (P>0.05) when compared to the control, but the same two parameters in20%or25%significantly rose (P＜0.05); no significant differences (P>0.05) between the four groups in abnormality of spermatozoa preserved for24h were observed4) the treatment II (1mmol/L melatonin+20%egg yolk) lead to better (P<0.05) motility and survival index of extended spermatozoa than the other three treatments; the treatment II and IV (1mmol/L melatonin+1mmol/L dopamine hydrochloride+20%egg yolk) caused more excellent (P＜0.05) survival effective time and acrosomal integrity (24h) of conserved spermatozoa than the other two treatments; the treatment IV brought about longer (P<0.05) survival overall time of stored spermatozoa than the other three treatments; the four treatments didn’t reveal any significant differences (P>0.05) in abnormality of spermatozoa preserved for24h. In conclusion, under the present experimental conditions, the optimal concentration of melatonin, dopamine hydrochloride and egg yolk is1mmol/L,1mmol/L and20%, respectively, when supplemented solely; and the combination of1mmol/L melatonin+20%egg yolk is prior to the other three combinations when added together.