Evaluation of the quality of bovine semen subjected to cryopreservation with hydroxypropylmethylcellulose.

The objective was to evaluate the effects of different concentrations of hydroxypropylmethylcellulose (HPMC) on the cryopreservation of bovine semen. Semen was collected from seven bulls by electroejaculation and diluted in Tris-egg yolk medium with and without glycerol (G) in the following treatments: C: Tris-Egg Yolk + 6 %G; T1: Tris-Egg Yolk + 3 % G; T2: Tris-Egg Yolk + 0 % G; T3: Tris-Egg Yolk + 0.5 % HPMC; T4: Tris-Egg Yolk + 1.0 % HPMC; T5: Tris-Egg Yolk + 1.5 % HPMC; T6: Tris-Egg Yolk + 5.5 % G + 0.5 % HPMC. Samples were frozen and stored at -196°C. After thawing, sperm quality was assessed using the rapid thermoresistance test (RTRT), sperm morphology, hypoosmotic swelling test, plasma membrane integrity, mitochondrial activity, and in vitro fertilization (IVF) test. RTRT results showed that the control group had better motility and vigor at 0', 15', and 30' compared to the T6 group. The T6 group had better results than other groups supplemented with 0.5 %, 1.0 %, and 1.5 % HPMC. No significant differences were observed at 45' for RTRT, hypoosmotic swelling, morphology, membrane integrity, mitochondrial activity, or IVF rates. In conclusion, the addition of HPMC reduced sperm motility and vigor but did not negatively affect other cryopreservation parameters.