Seminal plasma levels added to a Tris-based diluent for refrigerated sheep semen: results of the hyposmosis test and pregnancy rate

  • H. Bueno-Larroque Universidad de la Republica
  • Raquel Perez Clariget Universidad de la Republica
  • Alvaro Lopez
Keywords: Cooled ram semen, HOS test, Pregnancy rate, Seminal plasma


The work's objective was compared to the results of the hypo-osmotic swelling (HOS) test and pregnancy rate when different levels of seminal plasma (SP) were added to a Tris extender for cooled ram semen. The SP and 16 ejaculates were obtained from three high fertility adult Corriedale rams during the breeding season. Each ejaculate was divided into: a) Fresh semen (FS) used during an hour after collection; b) Tris (T); c) Tris + 30% (T+30) and d) Tris + 50% (T+50) of SP. Samples were challenged to the HOS test before diluted and after 2 and 24 h after the cooling process began. Nulliparous, Corriedale ewes with estrus synchronized were cervically inseminated with 0.2 mL containing 2 x 108 spermatozoa of: FS (n = 22), T (n = 28), T+30 (n = 31), T+50 (n = 30). The pregnancy rate was determined by ultrasound. The extender (P=0.002) influenced the response of the HOS test. At 2 and 24 h in T+30 and T+50 were observed higher percentages (P < 0.05) of swollen spermatozoa than FS, respectively. The pregnancy rate was affected by the extender (P=0.03). Pregnancy rates obtained with FS (87%) and with T+30 (81%) were higher (P<0.05) than those obtained with T (58%) y T+50 (54%). The addition of 30% but not 50% of ram SP to a Tris extender prevents the decrease in pregnancy rate when semen is stored at 5°C for 24 h before cervical AI.


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Aitken, R. J., B. Nixon. 2013. Sperm capacitation: a distant landscape glimpsed but unexplored. Molecular Human Reproduction, 19(12):785-793.

Barrios, B., R. Pérez-Pe, M. Gallego, A. Tato, J. Osada, T. Muiño-Blanco and J. A. Cebrián-Pérez. 2000. Seminal plasma proteins revert the cold-shock damage on ram sperm membrane, Biol Reprod, 63:1531-1537.

Boretto, J.M., A. E. Gibbons, M. M. Bunge, M. I. Cueto, F. Bidinodt. 2002. Relation between frozen-thawed semen quality and the reproductive efficiency of laparoscopic insemination in rams. [in Spanish] Revista de Medicina Veterinaria, 83(4):185-188.

Dominguez, M. P., A. Falcinelli, F. Hozbor, E. Sánchez, A. Cesari, R. H. Alberio. 2008. Seasonal variations in the composition of ram seminal plasma and its effect on frozen-thawed ram sperm. Theriogenology, 69:564-573.

Gillan, L., G. Evans, W. M. C. Maxwell. 1997. Capacitation status and fertility of fresh and frozen-thawed ram spermatozoa. Reprod Fertil Dev, 9:481-487.

Jeyendran, R. S., H. H. Van der Ven, M. Pérez-Pelaez, B. Crabo, G. Zaneveld. 1984. Development of an assay to assess the functional integrity of the human sperm membrane and its relationship to the other sperm characteristics, J Reprod Fertil. 70: 219-228.

Leahy, T., J. I. Marti, G. Evans, W. M. C. Maxwell. 2010. Seasonal variation in the protective effect of seminal plasma on frozen-thawed ram spermatozoa. Anim Reprod Sci, 119: 147-153.

Leahy, T. and B. M. Gadella. 2011. Sperm surface changes and physiological consequences induced by sperm handling and storage. Reproduction, 142: 759-778.

López-Pérez, A., R. Pérez-Clariget. 2012. Ram seminal plasma improves pregnancy rates in ewes cervically inseminated with ram semen stored at 5 ºC for 24 hours. Teriogenology, 77:395-399.

Maxwell, W. M. C., S. Salamon. 1993. Liquid storage of ram semen: a review. Reprod Fertil Dev, 5:613-638.

Muiño-Blanco, T., R. Pérez-Pe, J. Cebrián-Pérez. 2008. Seminal plasma proteins and sperm resistance to stress. Reprod Dom Anim, 43 (4):18-31.

Pérez-Pé, R., J. A. Cebrián-Pérez, T. Muiño-Blanco. 2001. Semen plasma proteins prevent cold-shock membrane damage to ram spermatozoa. Theriogenology, 56:425-434.

Ramu, S., R. S. Jeyendran. 2013.The hypo-osmotic swelling test for evaluation of sperm membrane integrity. Methods Mol Biol, 927:21-25.

Rota, A., N. Penzo, L. Vincent, R. Mantovani. 1999. Hypoosmotic swelling (HOS) as a screening assay for testing in vitro fertility of bovine spermatozoa. Theriogenology, 53:1415-1420.

Tartaglione, M., M. N. Ritta. 2004. Prognostic value of spermatological parameters as predictors of in vitro fertility of frozen-thawed bull semen. Theriogenology 62(7): 1245-1252.

Tartagni, M., M. M. Schonauer, E. Cicinelli, H. Selman, D. De Ziegler, F. Petruzzelli, V. D'Addario. 2002. Usefulness of the hypo-osmotic swelling test in predicting pregnancy rate and outcome in couples undergoing intrauterine insemination. J Androl, 23(4):498–502.

Vasan, S. S. 2011. Semen analysis and sperm function tests: How much to test? Indian J. Urol 27: 41-48.

How to Cite
Bueno-Larroque, H., Raquel Perez Clariget, and Alvaro Lopez. 2018. “Seminal Plasma Levels Added to a Tris-Based Diluent for Refrigerated Sheep Semen: Results of the Hyposmosis Test and Pregnancy Rate”. Latin American Archives of Animal Production 26 (1-2).
Original paper