INTEGRIDAD DE LA CROMATINA Y FORMA DE LA CABEZA DEL ESPERMATOZOIDE DE TORO: EVALUACIÓN SIMULTÁNEA CON LA TINCIÓN DE AZUL DE TOLUIDINA Chromatin Integrity and Shape Head of Bull Sperm: Simultaneous Assessment with Toluidine Blue Stain

The relationship between chromatin integrity and sperm head morphoanomalies was studied using the toluidine blue stain for the simultaneous assessment of both parameters. Thawed semen from five Brahman bulls was used. Sperm were stained and grouped into normal chromatin (stained light blue) and damaged chromatin (stained dark blue or violet) and effect of chromatin integrity on the percentage of head morphoanomalies was determined. Sperm with normal chromatin showed a significantly (P<0.0001) lower percentage of head morphoanomalies (2.13 ± 3.11%) that sperm with damaged chromatin (30.42 ± 2.84%). Some head morphoanomalies were almost exclusive of sperm with damaged chromatin, such as loose head (13.09 ± 2.44%), pyriform heads (6.96 ± 0.93%), vacuolated heads (5.04 ± 0.85%) and macrocephalic (4.32 ± 0.64%), in all cases, significantly differences were observed with sperm with normal chromatin, which the most abundant morphoanomaly was the pyriform head (1.81 ± 1.02%). In conclusion, chromatin integrity and sperm morphology are closely related and sperm with damaged chromatin have more head morphoanomalies than sperm with normal chromatin.