This study was carried out to investigate if the substitution of chicken egg yolk (CEY) with duck egg yolk (DEY) in extenders can i
mprove the quality of frozen-thawed se
men of
Nili-Ravi buffalo bulls and to study if reducing DEY level in extender affects the freezability results. Thirty se
men sa
mples collected fro
m three buffalo bulls were diluted in extenders A, B, C, D and E containing tris, citric acid, fructose, egg yolk, glycerol and antibiotics. Extender A contained 20%CEY (control), while extenders B, C, D and E contained 5, 10, 15 and 20%DEY, respectively. After freezing and storage for 24 h in liquid nitrogen, sa
mples were evaluated for post-thaw quality.
The post extension sperm motility did not differ between extenders A (control) and E (20%DEY). The same was true for post-thaw percentage of sperm with functional plasma membrane and percentage of sperm with abnormal heads or mid pieces. However, extender E showed higher (m>Pm> < 0.05) values for post-thaw sperm motility, livability and absolute index of livability of spermatozoa at 37 掳C compared to extender A. Spermatozoa with abnormal tail were lower (m>Pm> < 0.05) in extender E compared to extender A. Values of these parameters of post-thaw semen quality were highest for extender E containing 20%DEY and decreased significantly with decrease in the concentration of DEY, except sperm abnormalities (head, mid-piece and tail) which increased with decrease in DEY level. These results showed that replacement of 20%CEY with 20%DEY in extenders significantly improved post-thaw sperm motility, livability and absolute index of livability of spermatozoa and reduced tail abnormalities. Reduction in the level of DEY in extenders from 20%adversely affected post-thaw semen quality of Nili-Ravi buffalo bulls.