Sperm quality and seminal plasma proteins in three sheep breeds under high altitude and tropical conditions

Melissa Carvajal-Serna, Jaime A. Cardozo, Henry Grajales-Lombana, José A. Cebrián-Pérez, Teresa Muiño-Blanco


We tested the hypothesis that sheep breed can influence the sperm quality and seminal plasma (SP) composition and investigated any potential relationship between SP proteins and antioxidant enzyme activities (AO) with sperm quality. Ejaculates from twelve rams of three breeds were obtained during the rainy season at high altitudes, and sperm quality was automatically evaluated (CASA-Hamilton Thorne). The AO of superoxide dismutase, glutathione peroxide and glutathione reductase (GR) in SP was evaluated and total proteins were separated by SDS-PAGE. Comparative analyses of semen quality parameters between breeds revealed that Creole and Hampshire breeds had a higher sperm quality compared with Romney Marsh (p<0.05), although no difference in AO was found. GR activity was negatively correlated (p<0.05) with several kinematic variables and positively (p<0.05) with morphological abnormalities. The highest SP protein concentration was found in semen collected from Hampshire males compared with that from Creole and Romney Marsh (p<0.05). SDS-PAGE analysis showed the presence of 32 protein bands in SP with molecular weights between 334 and 10 kDa. Differences (p<0.05) between breeds in bands of 43, 25, 22 and 20 kDa were observed. These results evidence a relationship between the protective effect of the antioxidant enzyme system in SP of three ram types under high altitude and tropical conditions and semen quality. Our findings also suggest that the identified proteins might play an important role in sperm physiology and quality.


antioxidant defense enzymes; high-tropic; rainy season

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Abecia JA, Arrébola F, Macías A, Laviña A, González-Casquet O, Benítez F, Palacios C, 2016. Temperature and rainfall are related to fertility rate after spring artificial insemination in small ruminants. Int J Biometeorol 60: 1603-1609. https://doi.org/10.1007/s00484-016-1150-y

Agarwal A, Durairajanayagam D, Halabi J, Peng J, Vazquez-Levin M, 2014. Proteomics, oxidative stress and male infertility. Reprod Biomed Online 29: 32-58. https://doi.org/10.1016/j.rbmo.2014.02.013

Aitken RJ, Baker MA, 2004. Oxidative stress and male reproductive biology. Reprod Fertil Dev 16: 581-588. https://doi.org/10.1071/RD03089

Aitken RJ, Roman SD, 2008. Antioxidant systems and oxidative stress in the testes. ‎Adv Exp Med Biol 636: 154-171. https://doi.org/10.1007/978-0-387-09597-4_9

Aitken RJ, Gordon E, Harkiss D, Twigg JP, Milne P, Jennings Z, Irvine DS, 1998. Relative impact of oxidative stress on the functional competence and genomic integrity of human spermatozoa. Biol Reprod 59: 1037-1046. https://doi.org/10.1095/biolreprod59.5.1037

Almadaly EA, Farrag FA, Saadeldin IM, El-Magd MA, El-Razek IMA (2016) Relationship between total protein concentration of seminal plasma and sperm characteristics of highly fertile, fertile and subfertile Barki ram semen collected by electroejaculation. Small Rumin. Res. 144, 90-99. https://doi.org/10.1016/j.smallrumres.2016.07.023

Alvarez JG, Storey BT (1989) Role of glutathione peroxidase in protecting mammalian spermatozoa from loss of motility caused by spontaneous lipid peroxidation. Gamete Res. 23, 77-90. https://doi.org/10.1002/mrd.1120230108

Arrebola FA, Abecia JA, Forcada F, Garcia A, Martin RA, Mesa O (2009) Effects of annual rainfall and farm on lamb production after treatment with melatonin implants in merino sheep: A 4-year study. N Z Vet J 57, 3 141-145. https://doi.org/10.1080/00480169.2009.36893

Arrebola F, Palacios C, Gil M-J, Abecia JA (2016) Management and meteorological factors affect fertility after artificial insemination in Murciano-Granadina goats after arti fi cial insemination in Murciano-Granadina goats. ‎Animal Prod. Sci 56, 1906-1912. https://doi.org/10.1071/AN15176

Asadpour R (2012) Relationship between mineral composition of seminal plasma and semen quality in various ram breeds. Acta Sci Vet 40, 1-8.

Avdi M, Banos G, Stefos K, Chemineau P (2004) Seasonal variation in testicular volume and sexual behavior of Chios and Serres rams. Theriogenology 62, 275-282. https://doi.org/10.1016/j.theriogenology.2003.10.004

Bailey RW, Aronow B, Harmony J a K, Griswold MD (2002) Heat shock-initiated apoptosis is accelerated and removal of damaged cells is delayed in the testis of clusterin/ApoJ knock-out mice. Biol Reprod 66, 1042-1053. https://doi.org/10.1095/biolreprod66.4.1042

Barrios B, Pérez-Pé R, Gallego M, Tato A, Osada J, Muiño-Blanco T, Cebrián-Pérez JA (2000) Seminal Plasma Proteins Revert the Cold-Shock Damage on Ram Sperm Membrane. Biol Reprod 24, 352-359.

Barrios B, Fernández-Juan M, Muiño-Blanco T, Cebrián-Pérez JA (2005) Immunocytochemical Localization and Biochemical Characterization of Two Seminal Plasma Proteins That Protect Ram Spermatozoa Against Cold Shock. J. Andrology 26, 539-549. https://doi.org/10.2164/jandrol.04172

Belleannée C, Labas V, Teixeira-Gomes AP, Gatti JL, Dacheux JL, Dacheux F (2011) Identification of luminal and secreted proteins in bull epididymis. J. Proteom. 74, 59-78. https://doi.org/10.1016/j.jprot.2010.07.013

Bergeron A, Villemure M, Lazure C, Manjunath P (2005) Isolation and characterization of the major proteins of ram seminal plasma. Mol. Reprod. Dev.71, 461-470. https://doi.org/10.1002/mrd.20310

Bernardini A, Hozbor F, Sanchez E, Fornés MW, Alberio RH, Cesari A (2011) Conserved ram seminal plasma proteins bind to the sperm membrane and repair cryopreservation damage. Theriogenology 76, 436-447. https://doi.org/10.1016/j.theriogenology.2011.02.020

Blaschuk O, Burdzy K, Fritz IB (1983) Purification and characterization of a cell-aggregating factor (clusterin), the major glycoprotein in ram rete testis fluid. J. Biol. Chem. 258, 7714-7720.

Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 72, 248-254. https://doi.org/10.1016/0003-2697(76)90527-3

Bravo S, Larama G, Ortíz M, Sepúlveda N (2015) Genetic differentiation between 'Araucana' creole and 'Hampshire Down' sheeps in Chile. ChileanJAR 75, 131-136.

Caballero I, Parrilla I, Almiñana C, del Olmo D, Roca J, Martínez EA, Vázquez JM (2012) Seminal Plasma Proteins as Modulators of the Sperm Function and Their Application in Sperm Biotechnologies. Reprod Domest Anim 47, 12-21. https://doi.org/10.1111/j.1439-0531.2012.02028.x

Calamera J, Buffone M, Ollero M, Alvarez J, Doncel GF (2003) Superoxide Dismutase Content and Fatty Acid Composition in Subsets of Human Spermatozoa from Normozoospermic, Asthenozoospermic, and Polyzoospermic Semen Samples. Mol. Reprod. Dev.66, 422-430. https://doi.org/10.1002/mrd.10368

Câmara DR, Mello-Pinto MMC, Pinto LC, Brasil OO, Nunes JF, Guerra MMP (2011) Effects of reduced glutathione and catalase on the kinematics and membrane functionality of sperm during liquid storage of ram semen. Small Rumin. Res. 100, 44-49. https://doi.org/10.1016/j.smallrumres.2011.05.010

Cardozo JA, Fernández-Juan M, Forcada F, Abecia A, Muiño-Blanco T, Cebrián-Pérez JA (2006) Monthly variations in ovine seminal plasma proteins analyzed by two-dimensional polyacrylamide gel electrophoresis. Theriogenology 66, 841-850. https://doi.org/10.1016/j.theriogenology.2006.01.058

Cardozo JA, Fernández-Juan M, Cebrián-Pérez JA, Muiño-Blanco T (2008) Identification of RSVP14 and RSVP20 components by two-dimensional electrophoresis and western-blotting. Reprod Domest Anim 43, 15-21.

Carvajal-serna M, Cortés-lópez HA, Manrique-Perdomo C, Grajales-Lombana H (2018) Evaluación de los parámetros de calidad seminal y cinemática espermática en tres razas ovinas de lana en condiciones de trópico alto colombiano. Revista de Medicina Veterinaria 36, 49-61.

Casao A, Pérez-Pé R, Abecia JA, Forcada F, Muiño-Blanco T, Cebrián-Pérez J álvaro (2013) The effect of exogenous melatonin during the non-reproductive season on the seminal plasma hormonal profile and the antioxidant defence system of Rasa Aragonesa rams. Anim Reprod Sci 138, 168-174. https://doi.org/10.1016/j.anireprosci.2013.02.002

Colás C, Pérez-Pé R, Muiño-Blanco T, Cebrián-Pérez JÁ (2009) Changes in actin distribution of Ram spermatozoa under different experimental conditions. Reprod Domest Anim 44, 221-227. https://doi.org/10.1111/j.1439-0531.2007.01033.x

Desnoyers L, Manjunath P (1992) Major proteins of bovine seminal plasma exhibit novel interactions with phospholipid. J. Biol. Chem. 267, 10149-10155.

Domínguez MP, Falcinelli A, Hozbor F, Sánchez E, Cesari A, Alberio RH (2008) Seasonal variations in the composition of ram seminal plasma and its effect on frozen-thawed ram sperm. Theriogenology 69, 564-573. https://doi.org/10.1016/j.theriogenology.2007.11.010

El-Hajj Ghaoui R, Thomson PC, Leahy T, Evans G, Maxwell WMC (2007) Autologous whole ram seminal plasma and its vesicle-free fraction improve motility characteristics and membrane status but not in vivo fertility of frozen-thawed ram spermatozoa. Reprod Domest Anim 42, 541-549. https://doi.org/10.1111/j.1439-0531.2006.00819.x

Fernandez-Juan M (2006) Immunohistochemical Localization of Sperm-Preserving Proteins in the Ram Reproductive Tract. J. Andrology 27, 588-595. https://doi.org/10.2164/jandrol.05187

Fritz IB, Burdzy K, Sétchell B, Blaschuk O (1983) Ram rete testis fluid contains a protein (clusterin) which influences cell-cell interactions in vitro. Biol Reprod 28, 1173-1188. https://doi.org/10.1095/biolreprod28.5.1173

Galina MA, Morales R, Silva E, López B (1996) Reproductive performance of Pelibuey and Blackbelly sheep under tropical management systems in Mexico. Small Rumin. Res. 22, 31-37. https://doi.org/10.1016/0921-4488(95)00878-0

de Graaf SP, Evans G, Gillan L, Guerra MMP, Maxwell WMC, O'Brien JK (2007) The influence of antioxidant, cholesterol and seminal plasma on the in vitro quality of sorted and non-sorted ram spermatozoa. Theriogenology 67, 217-227. https://doi.org/10.1016/j.theriogenology.2006.07.008

de Lamirande E, Gagnon C (1995) Impact of reactive oxygen species on spermatozoa : a balancing act between beneficial and detrimental effects. Hum Reprod 10, 15-21. https://doi.org/10.1093/humrep/10.suppl_1.15

de Lamirande E, Jiang H, Zini a, Kodama H, Gagnon C (1997) Reactive oxygen species and sperm physiology. Rev. Reprod. 2, 48-54. https://doi.org/10.1530/ror.0.0020048

du Plessis SS, Kashou AH, Benjamin DJ, Yadav SP, Agarwal A (2011) Proteomics: a subcellular look at spermatozoa. Reprod Biol Endocrinol. : RB&E 9, 36.

Gundogan M, Yeni D, Avdatek F, Fidan AF (2010) Influence of sperm concentration on the motility, morphology, membrane and DNA integrity along with oxidative stress parameters of ram sperm during liquid storage. Anim Reprod Sci 122, 200-207. https://doi.org/10.1016/j.anireprosci.2010.08.012

Gwathmey TM, Ignotz GG, Mueller JL, Manjunath P, Suarez SS (2006) Bovine Seminal Plasma Proteins PDC-109, BSP-A3, and BSP-30-kDa Share Functional Roles in Storing Sperm in the Oviduct. Biol Reprod 75, 501-507. https://doi.org/10.1095/biolreprod.106.053306

Hernández M, Roca J, Calvete JJ, Sanz L, Muiño-Blanco T, Cebrián-Pérez J a, Vázquez JM, Martínez E a (2007) Cryosurvival and in vitro fertilizing capacity postthaw is improved when boar spermatozoa are frozen in the presence of seminal plasma from good freezer boars. J. Andrology 28, 689-97. https://doi.org/10.2164/jandrol.107.002725

Humphreys DT, Carver JA, Easterbrook-Smith SB, Wilson MR (1999) Clusterin has chaperone-like activity similar to that of small heat shock proteins. J. Biol. Chem. 274, 6875-6881. https://doi.org/10.1074/jbc.274.11.6875

Ibrahim NM, Troedsson MHT, Foster DL, Loseth KJ, Farris JA, Blaschuk O, Crabo BG (1999) Reproductive Tract Secretions and Bull Spermatozoa Contain Different Clusterin Isoforms That Cluster Cells and Inhibit Complement-Induced Cytolisis. J. Andrology 20, 230-240.

Ibrahim NM, Gilbert GR, Loseth KJ, Crabo BG (2000) Correlation between clusterin-positive spermatozoa determined by flow cytometry in bull semen and fertility. J. Andrology 21, 887-894.

Ibrahim NM, Romano JE, Troedsson MH, Crabo BG (2001) Effect of scrotal insulation on clusterin-positive cells in ram semen and their relationship to semen quality. J. Andrology 22, 863-877.

Ibrahim SA (1997) Seasonal variations in semen quality of local and crossbred rams raised in the United Arab Emirates. Anim Reprod Sci 49, 161-167. https://doi.org/10.1016/S0378-4320(97)00063-8

Jobim MIM, Oberst ER, Salbego CG, Wald VB, Horn AP, Mattos RC (2005) BSP A1/A2-like proteins in ram seminal plasma. Theriogenology 63, 2053-2062. https://doi.org/10.1016/j.theriogenology.2004.10.002

Karagiannidis A, Varsakeli S, Alexopoulos C, Amarantidis I (2000) Seasonal variation in semen characteristics of Chios and Friesian rams in Greece. Small Rumin. Res. 37, 125-130. https://doi.org/10.1016/S0921-4488(99)00143-1

Kasimanickam R, Pelzer KD, Kasimanickam V, Swecker WS, Thatcher CD (2006) Association of classical semen parameters, sperm DNA fragmentation index, lipid peroxidation and antioxidant enzymatic activity of semen in ram-lambs. Theriogenology 65, 1407-1421. https://doi.org/10.1016/j.theriogenology.2005.05.056

Kasimanickam R, Kasimanickam V, Pelzer KD, Dascanio JJ (2007) Effect of breed and sperm concentration on the changes in structural, functional and motility parameters of ram-lamb spermatozoa during storage at 4ºC. Anim Reprod Sci 101, 60-73. https://doi.org/10.1016/j.anireprosci.2006.09.001

Kommisrud E, Paulenz H, Sehested E, Grevle IS (2002) Influence of boar and semen parameters on motility and acrosome integrity in liquid boar semen stored for five days. Acta Vet Scand 43, 49-55. https://doi.org/10.1186/1751-0147-43-49

Laemmli UK (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227, 680-685. https://doi.org/10.1038/227680a0

Leahy T, de Graaf SP (2012) Seminal plasma and its effect on ruminant spermatozoa during processing. Reprod Domest Anim 47, 207-213. https://doi.org/10.1111/j.1439-0531.2012.02077.x

Leahy TA, Marti JIB, Evans GA, Maxwell WMCA (2009) Seminal plasma proteins protect flow-sorted ram spermatozoa from freeze - thaw damage. Reprod Fertil Dev. 21, 571-578. https://doi.org/10.1071/RD08238

Leahy T, Marti JI, Evans G, Maxwell WMC, 2010a. Seasonal variation in the protective effect of seminal plasma on frozen-thawed ram spermatozoa. Anim Reprod Sci 119: 147-153. https://doi.org/10.1016/j.anireprosci.2009.12.010

Leahy T, Evans G, Maxwell WMC, Marti JI, 2010b. Seminal plasma proteins do not consistently improve fertility after cervical insemination of ewes with non-sorted or sex-sorted frozenthawed ram spermatozoa. Reprod Fertil Dev 22: 606-612. https://doi.org/10.1071/RD09207

Leahy T, Marti JI, Crossett B, Evan G, Maxwell WMC (2011) Two-dimensional polyacrylamide gel electrophoresis of membrane proteins from flow cytometrically sorted ram sperm. Theriogenology 75, 962-971. https://doi.org/10.1016/j.theriogenology.2010.11.003

Ledesma A, Manes J, Cesari A, Alberio R, Hozbor F (2014) Electroejaculation Increases Low Molecular Weight Proteins in Seminal Plasma Modifying Sperm Quality in Corriedale Rams. Reprod Domest Anim 49, 324-332. https://doi.org/10.1111/rda.12279

Lewis S, Sterling S, Young I, Thompson W. (1997) Comparison of individual antioxidants and total antioxidant capacity of sperm and seminal plasma in fertile and infertile men. Fertil Steril 67, 142-147. https://doi.org/10.1016/S0015-0282(97)81871-7

Luna C, Yeste M, Rivera Del Alamo MM, Domingo J, Casao A, Rodriguez-Gil JE, Pérez-Pé R, Cebrián-Pérez JA, Muino-Blanco T (2015) Effect of seminal plasma proteins on the motile sperm subpopulations in ram ejaculates. Reprod Fertil Dev. doi:10.1071/RD15231. https://doi.org/10.1071/RD15231

Manjunath P, Thérien I (2002) Role of seminal plasma phospholipid-binding proteins in sperm membrane lipid modification that occurs during capacitation.J. Reprod. Immunol.53, 109-119. https://doi.org/10.1016/S0165-0378(01)00098-5

Manjunath P, Nauc V, Bergeron a, Menard M (2002) Major proteins of bovine seminal plasma bind to the low-density lipoprotein fraction of hen's egg yolk. Biol Reprod 67, 1250-1258. https://doi.org/10.1095/biolreprod67.4.1250

Manjunath P, Lefebvre J, Jois PS, Fan J, Wright MW (2008) New Nomenclature for Mammalian BSP Genes. Biol Reprod 80, 394-397. https://doi.org/10.1095/biolreprod.108.074088

Marai IFM, El-Darawany AA, Fadiel A, Abdel-Hafez MAM (2007) Physiological traits as affected by heat stress in sheep-A review. Small Rumin. Res. 71, 1-12. https://doi.org/10.1016/j.smallrumres.2006.10.003

Marco-Jiménez F, Vicente JS, Viudes-De-Castro MP (2008) Seminal plasma composition from ejaculates collected by artificial vagina and electroejaculation in Guirra ram. Reprod Domest Anim 43, 403-408. https://doi.org/10.1111/j.1439-0531.2007.00923.x

Marti E, Mara L, Marti JI, Muiño-Blanco T, Cebrián-Pérez JA (2007) Seasonal variations in antioxidant enzyme activity in ram seminal plasma. Theriogenology 67, 1446-1454. https://doi.org/10.1016/j.theriogenology.2007.03.002

Maxwell WMC, Stojanov T (1996) Liquid storage of ram semen in the absence or presence of some antioxidants. Reprod Fertil Dev8, 1013-1020. https://doi.org/10.1071/RD9961013

Maxwell WMC, Long CR, Johnson LA, Dobrinsky JR, Welch GR (1998) The relationship between membrane status and fertility of boar spermatozoa after flow cytometric sorting in the presence or absence of seminal plasma. Reprod Fertil Dev10, 433-440. https://doi.org/10.1071/RD98102

Mendoza N, Casao A, Del Valle I, Serrano E, Nicolau S, Asumpção MEOA, Muiño-Blanco T, Cebrián-Pérez JA, Pérez-Pé R (2012) Quality characteristics and fertilizing ability of ram sperm subpopulations separated by partition in an aqueous two-phase system. J Chromatogr B Analyt Technol Biomed Life Sci 880, 74-81. https://doi.org/10.1016/j.jchromb.2011.11.019

Mendoza N, Casao A, Pérez-Pé R, Cebrián-Pérez J a, Muiño-Blanco T (2013) New insights into the mechanisms of ram sperm protection by seminal plasma proteins. Biol Reprod 88, 149. https://doi.org/10.1095/biolreprod.112.105650

Mohamed, S.A., 1978. Studies on some reproductive characters of native sheep. MS. thesis, Animal Production Dept., Faculty of Agriculture, Cairo Univ., Egypt.

Mortimer ST (2000) CASA — Practical Aspects Andrology Lab Corner. J. Andrology, 21, 515-524.

Mortimer ST, Maxwell WM (1999) Kinematic definition of ram sperm hyperactivation. Reprod Fertil Dev 11, 25-30. http://www.ncbi.nlm.nih.gov/pubmed/10680999, https://doi.org/10.1071/RD99019

Muciaccia B, Pensini S, Culasso F, Padula F, Paoli D, Gandini L, Di Veroli C, Bianchini G, Stefanini M, D'Agostino A (2012) Higher clusterin immunolabeling and sperm DNA damage levels in hypertensive men compared with controls. Hum Reprod27, 2267-2276. https://doi.org/10.1093/humrep/des173

Muhammad Aslam MK, Kumaresan A, Sharma VK, Tajmul M, Chhillar S, Chakravarty AK, Manimaran A, Mohanty TK, Srinivasan A, Yadav S (2014) Identification of putative fertility markers in seminal plasma of crossbred bulls through differential proteomics. Theriogenology 82, 1254-1262. https://doi.org/10.1016/j.theriogenology.2014.08.007

Muiño-Blanco T, Pérez-Pé R, Cebrián-Pérez JA (2008) Seminal plasma proteins and sperm resistance to stress. Reprod Domest Anim 43, 18-31. https://doi.org/10.1111/j.1439-0531.2008.01228.x

O'Bryan MK, Baker HWG, Saunders JR, Kirszbaum L, Walker ID, Hudson P, Liu DY, Glew MD, D'Apice AJF, Murphy BF (1990) Human seminal clusterin (SP-40,40): Isolation and characterization. J. Clin. Investig 85, 1477-1486. https://doi.org/10.1172/JCI114594

O'Bryan MK, Mallidis C, Murphy BF, Baker HW (1994) Immunohistological localization of clusterin in the male genital tract in humans and marmosets. Biol Reprod 50, 502-509. https://doi.org/10.1095/biolreprod50.3.502

Palacios C, Abecia JA (2014) Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study. Int. J. Biometeorol 59, 585-592. https://doi.org/10.1007/s00484-014-0872-y

Pérez B, Mateos E (1996) Effect of photoperiod on semen production and quality in bucks of Verata and Malaguena breeds. Small Rumin. Res. 23, 23-28. https://doi.org/10.1016/S0921-4488(96)00899-1

Perez-Pe R, Marti JI, Tejedor A, Muiño-Blanco T, Cebrian-Perez JA (2001) Semen plasma proteins prevent cold-shock membrane damage to ram spermatozoa. Theriogenology 426-434. https://doi.org/10.1016/S0093-691X(01)00574-X

Pérez-Pé R, Grasa P, Fernández-Juan M, Peleato ML, Cebrián-Pérez JÁ, Muiño-Blanco T (2002) Seminal plasma proteins reduce protein tyrosine phosphorylation in the plasma membrane of cold-shocked ram spermatozoa. Mol. Reprod. Dev.61, 226-233. https://doi.org/10.1002/mrd.1152

Rickard JP, Leahy T, Soleilhavoup C, Tsikis G, Labas V, Harichaux G, Lynch GW, Druart X, de Graaf SP (2015) The identification of proteomic markers of sperm freezing resilience in ram seminal plasma. J. Proteom. 126, 303-311. https://doi.org/10.1016/j.jprot.2015.05.017

Rodríguez-Martínez H, Kvist U, Ernerudh J, Sanz L, Calvete JJ (2011) Seminal plasma proteins: What role do they play? AmericanJ. Reprod. Immunol.66, 11-22. https://doi.org/10.1111/j.1600-0897.2011.01033.x

Rosa HJD, Bryant MJ (2003) Seasonality of reproduction in sheep. Small Rumin. Res. 48, 155-171. https://doi.org/10.1016/S0921-4488(03)00038-5

Salehi M, Akbari H, Heidari MH, Molouki A, Murulitharan K, Moeini H, Novin MG, Aabed F, Taheri H, Fadaei F, Mohsenzadeh M, Jafari M, Pirouzi A, Heidari R (2013) Correlation between human clusterin in seminal plasma with sperm protamine deficiency and DNA fragmentation. Mol. Reprod. Dev.80, 718-724. https://doi.org/10.1002/mrd.22202

Sensibar JA, Qian YI, Griswold MD, Sylvester SR, Bardin CW, Cheng CYAN, Lee C (1993) Localization and Molecular Heterogeneity of Sulfated Glycoprotein-2 (Clusterin) among Ventral Prostate, Seminal Vesicle, Testis, and Epididymis of Rats Biol Reprod . 242, 233-242.

Serrano E, Martínez AB, Arruga D, Pérez-Pé R, Sánchez-Ferrer Á, Muiño-Blanco T, Cebrián-Pérez JA (2015) New insights into the phylogeny and gene context analysis of binder of sperm proteins (BSPs). PLoS ONE 10, 1-19. https://doi.org/10.1371/journal.pone.0137008

Sharma L, Pandey V, Nigam R, Saxena A, Swain DK (2015) Association of Semen Attributes and Seminal Plasma Proteins of Buffalo Bulls. Journal of Animal Research 5, 1. 119-123. https://doi.org/10.5958/2277-940X.2015.00020.0

Shiva M, Gautam AK, Verma Y, Shivgotra V, Doshi H, Kumar S (2011) Association between sperm quality, oxidative stress, and seminal antioxidant activity. ‎Clin. Biochem 44, 319-324. https://doi.org/10.1016/j.clinbiochem.2010.11.009

Shojaei Saadi HA, van Riemsdijk E, Dance AL, Rajamanickam GD, Kastelic JP, Thundathil JC (2013) Proteins associated with critical sperm functions and sperm head shape are differentially expressed in morphologically abnormal bovine sperm induced by scrotal insulation. J. Proteom. 82, 64-80. https://doi.org/10.1016/j.jprot.2013.02.027

Sikka SC (1996) Oxidative stress and role of antioxidants in normal and abnormal sperm function. Front Biosci 1, 78-86. https://doi.org/10.2741/A146

Smith JF, Parr J, Murray GR, McDonald RM, Lee R.-F (1999) Seasonal changes in the protein content and composition of ram seminal plasma. NZ Soc Anim Prod Proc 59, 223-225.

Soleilhavoup C, Tsikis G, Labas V, Harichaux G, Kohnke PL, Dacheux JL, Guérin Y, Gatti JL, de Graaf SP, Druart X (2014a) Ram seminal plasma proteome and its impact on liquid preservation of spermatozoa. J. Proteom. 109, 245-260. https://doi.org/10.1016/j.jprot.2014.07.007

Soma P, Kotze A, Grobler JP, van Wyk JB (2012) South African sheep breeds: Population genetic structure and conservation implications. Small Rumin. Res. 103, 112-119. https://doi.org/10.1016/j.smallrumres.2011.09.041

Storey BT, Alvarez JG, Thompson KA (1998) Human sperm glutathione reductase activity in situ reveals limitation in the glutathione antioxidant defense system due to supply of NADPH. Mol. Reprod. Dev.49, 400-407. https://doi.org/10.1002/(SICI)1098-2795(199804)49:4<400::AID-MRD7>3.0.CO;2-R

Sylvester SR, Morales C, Oko R, Griswold MD (1991) Localization of sulfated glycoprotein-2 (clusterin) on spermatozoa and in the reproductive tract of the male rat. Biol Reprod 45, 195-207. https://doi.org/10.1095/biolreprod45.1.195

Taha TA, Abdel-Gawad EI, Ayoub MA (2000) Monthly variations in some reproductive parameters of Barki and Awassi rams throughout 1 year under subtropical conditions. 1. Semen characteristics and hormonal levels. Animal Science 71, 317-324. https://doi.org/10.1017/S1357729800055168

Tung PS, Fritz IB (1985) Immunolocalization of clusterin in the ram testis, rete testis, and excurrent ducts. Biol Reprod 33, 177-186. https://doi.org/10.1095/biolreprod33.1.177

DOI: 10.5424/sjar/2018162-12882