The aim of this study was to identify the effects of adding quercetin (Q) to Tris ex
tender in order to identify levels of oxidative stress in bull sperm after freeze thawing.
Ejaculates were collected via artificial vagina from Holstein bulls. Semen was divided
into five tools and diluted to a final concentration of 15 × 106 spermatozoa/ml with
the Tris extender containing Q (25, 50, 100 and 200 μg/ml) and no additive (control;
C). All examples were equilibrated at 4°C during 4 hr then were loaded into 0.25- ml
straws and frozen using a controlled rate. Sperm motility and motility characteristics
were determined using the computer- assisted semen analyser. Sperm membrane in
tegrity was assessed using the hypoosmotic swelling test. Sperm chromatin integrity
was investigated using the single cell gel electrophoresis. Total antioxidant capacities
were performed colorimetrically. Q supplementation used as an antioxidant did not
produce better results in the proportion of sperm progressive and total motility,
plasma membrane integrity and sperm abnormalities. Q supplementation exhibited
the favourable tail length, tail DNA and tail moment. In conclusion, when whole pa
rameters are considered, Q25 can be added to the Tris extender due to its positive
effect on sperm DNA integrity and no adverse effect on the progressive and total
motilities of sperm.