Polymorphism of transferrin of carp seminal plasma: Relationship to blood transferrin and sperm motility characteristics Mariola Wojtczak a, ⁎ , Grzegorz J. Dietrich a , Ilgiz Irnazarow b , Patrycja Jurecka b , Mariola Słowińska a , Andrzej Ciereszko a a Semen Biology Group, Institute of Animal Reproduction and Food Research, 10-747 Olsztyn, ul. Tuwima 10, Poland b Institute of Ichthyobiology and Aquaculture of Polish Academy of Science Golysz, 43-520 Chybie, Poland Received 21 June 2007; received in revised form 23 July 2007; accepted 24 July 2007 Available online 1 August 2007 Abstract Transferrin (Tf) is a major protein of carp (Cyprinus carpio) seminal plasma. Its relationship with milt quality is unknown. In this study, we sought to determine if Tf is polymorphic in carp seminal plasma and if this polymorphism is related to sperm motility characteristics. We screened males of purebred common carp line (Polish line R6) for Tf polymorphism in blood plasma. The majority of Tf genotypes represented only DD and DG variants. We then collected milt from preselected DD and DG genotypes and tested their sperm motility characteristics using computer-aided sperm analysis (CASA). Tf polymorphism in seminal plasma was found to be identical with that of blood. However, the relationships between Tf polymorphism and iron metabolic parameters were different for blood and semen. These data suggest different regulation of Tf in liver and testis. We found substantial differences in sperm motility characteristics between both genotypes. Spermatozoa of DG males were characterized by lower curvilinear velocity (VCL), amplitude of lateral head displacement (ALH), higher linearity (LIN) and straightness (STR) of movement as compared to DD males. No differences were found in other sperm characteristics such as sperm concentration and percentage of sperm motility. Our results suggest that sperm motility parameters are related to Tf polymorphism and therefore this polymorphism may be related to sperm competitive ability. © 2007 Elsevier Inc. All rights reserved. Keywords: Carp; Polymorphism; Seminal plasma; Spermatozoa; Sperm motility; Transferrin 1. Introduction Transferrin (Tf), a major protein of iron metabolism in higher vertebrates, ensures the transfer of iron (III) ions, through biological fluids, from uptake to utilization sites (Lambert et al., 2005). Transferrin is a major serum protein and an 80 kDa single glycoprotein composed of two structurally similar lobes, each of which contains an iron-binding site. Tf is synthesized predom- inately by hepatocytes however it is also expressed in Sertoli, ependymal, and oligodendrodial cells (Gomme and McCann, 2005). Although Tf is widely known as an iron-binding protein, it is actually recognized as multi-task protein. Multiple biological actions of Tf include antioxidative and antimicrobial protection and growth, differentiation and cytoprotection activities (Gomme and McCann, 2005). Transferrin is a major component of iron shuttle in the testis of vertebrates (Sylvester and Griswold, 1994) and was found to be synthesized by Sertoli cells and involved in the net transport of ferric ions to germ cells (Sylvester and Griswold, 1993). The latter demonstrated that Tf in rats delivers iron to the spermatocytes and spermatids in the adluminal compartment and is presumably released as apotransferrin into the intercellular space and the tubular fluid. In this species, transferrin binds specifically to pachytene spermatocytes (Holmes et al., 1983). Mutant mice that lacks the ability to synthesize normal amounts of Tf have reduced ability to produce functional spermatozoa (Bernstein, 1987). Tf levels in seminal plasma are regarded as markers of spermato- genesis and significant correlations are reported between sperm concentration and motility characteristics (Barthelemy et al., 1988; Ber et al., 1990; Gilmont et al., 1990; Zalata et al., 1996). In vertebrates Tf is characterized by a significant degree of genetic polymorphism (Kamboh and Ferrell, 1987). Some transferrin variants are linked with pathology; for example Beckman and Beckman (1986) proposed that in humans TfC2 is Available online at www.sciencedirect.com Comparative Biochemistry and Physiology, Part B 148 (2007) 426 – 431 www.elsevier.com/locate/cbpb ⁎ Corresponding author. Tel.: +48 89 535 7423; fax: +48 89 535 7421. E-mail address: mario@pan.olsztyn.pl (M. Wojtczak). 1096-4959/$ - see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.cbpb.2007.07.011