The Effect of Coconut Milk in Extender on the Durability of Ram Sperm in Cool Conditions

Long-term storage of liquid sperm causes changes in the morphological structures and sperm function. This study was performed to determine the effect of different levels of coconut milk in ram sperm extender on sperm quality parameters after storage in cool conditions. Sperm were collected twice a week from three adult Lori rams using an artificial vagina. After collection and initial evaluation of the samples, the selected ejaculates were mixed and the mixed semen was divided into six equal parts and each part was diluted in a ratio of one to 20, with different diluents. Six extenders were prepared by adding different levels of coconut milk (5, 10, 15 and 20% (volume/volume) and egg yolk (15% (volume/volume)) to the Tris base extender. Diluted semen was stored at 5 ° C for 72 h. The samples at 0, 3, 6, 24, 48, and 72 h were evaluated for sperm motility parameters (computer analysis system) viability (Eosin nigrosin staining), morphology (Hancock), membrane integrity (HOST), lipid peroxidation rate, and sperm DNA fragmentation rate. The experiment was performed in a completely randomized design and the data analysis was performed using SAS statistical software. The results showed that extenders containing coconut milk in terms of some motility parameters including VSL, ALH, VAP, VCL were not significantly different from extender containing egg yolk (p≥0.05). But in terms of total and progressive sperm, Lin, STR, and BCF were significantly lower than extender containing egg yolk (p<0.05). Survival, cell membrane activity, and normal sperm percentage were similar in all treatments (p≥0.05). Also, the rate of lipid peroxidation and the percentage of sperm with damaged DNA were not affected by the type of extender. In general, the results of this study showed that the use of coconut milk in ram sperm extender to preserve sperm in cold conditions, could not maintain sperm motility parameters as much as the yolk and it was not a suitable substitute for yolk in ram sperm extender.