Seminal vesicle secretion of African catfish, its composition, its behaviour in water and saline solutions and its influence on gamete fertilizability

Abstract

The seminal vesicle secretion (SVS) of the African catfish, Clarias gariepinus, was investigated by analytical and experimental methods. SVS consists mainly of proteins and glycoproteins which are responsible for its viscous and sticky nature. The secretion contains also high activities of acid phosphatase, alkaline phosphatase, and proteases. These catabolic enzymes do not have functions in autolysis or liquefaction of SVS but are considered to eliminate aging spermatozoa from the proximal portions of seminal vesicle and from the spermatic duct. SVS of the African catfish is unstable in the environment relevant for natural spawning. When SVS was mixed with water, seminal plasma or different types of saline solutions its protein coagulated forming fibrous or granular particles of variable size within a few seconds. Pure SVS completely inhibited the motility as the sticky secretion hindered spermatozoa in free swimming. SVS had also a negative effect on sperm fertility, egg fertility, and sperm egg contact, as the fertilization was drastically suppressed in the presence of SVS. Basing on our analytical and experimental results we exclude that SVS has functions in stabilizing the viability of spermatozoa stored in the spermatic ducts or is an energy resource of spermatozoa. It also does not improve or stabilize the fertilization process and has no functions in adhering the eggs to substrates or in covering the eggs for mechanical protection or antibacterial defense. A function of SVS in the male and female communication during the prenuptial spawning behaviour is discussed.

Seminal vesicle and its role in the reproduction of teleosts

“…An understanding of the physical nature and chemical constituents of SVP is fundamental to know its functional role in sperm storage and motility, and fertilization. Several studies (Table 1) have described the physical and chemical composition of testicular fluid or seminal plasma (Kruger et al 1984;Lahnsteiner et al , 1993aLahnsteiner et al , 1994Lahnsteiner et al , 1995Lahnsteiner et al , 1996Kara et al 1996;Ohta et al 1997;Tan-Fermin et al 1999), but only a few are available on seminal vesicle fluid (SVF) (Steyn and van Vuren 1987;Lahnsteiner et al 1992a;Chowdhury and Joy 2001a;Mansour et al 2004). However, a comprehensive analysis of SV secretion is not yet available.…”

“…In parallel with the maturation of the testis, the SV epithelial cells secrete a mucopolysaccharide-proteinlipid-rich fluid (seminal vesicular fluid, SVF) whose content increases progressively and reaches a peak level in the spawning phase (Nayyar and Sundararaj 1970;van den Hurk et al 1987a, b;Singh and Joy 1999;Chowdhury andJoy 2000b, 2001a;Mansour et al 2004). The term SVF is used to denote spermatozoa plus seminal vesicle plasma (SVP).…”

“…Such modifications have been reported in blennies, gobies, charids, pimelodids, and catfishes and are described variously as testicular glands, testicular blind pouches, and seminal vesicles or sperm duct glands (Colombo and Burighel 1974;Patzner and Seiwald 1987a, b;de Jonge et al 1989;Patzner 1987, 1989;Lahnsteiner et al , 1992aFishelson et al 1994;Joy and Singh 1998;Singh and Joy 1998a;Meisner et al 2000;Richtarski and Patzner 2000;Hamlett et al 2002;Reardon et al 2002;Cruz and Santos 2004). Various functions are attributed to these, such as differentiation of spermatids, storage and nutrition of spermatozoa, secretion of sialomucins, proteins and enzymes, storage of lipids and phospholipids, production of steroids and steroid conjugates, phagocytosis of residual germ cells, pheromonal function, and the enhancement of sperm motility and fertilization efficiency (Sundararaj and Nayyar 1969a;Lahnsteiner et al , 1992avan den Hurk and Resink 1992;Ohta et al 1997;Singh and Joy 1999;Chowdhury and Joy 2001a;Mansour et al 2004) (Fig. 1).…”

Sperm characteristics in perch Perca fluviatilis L.

“…Piironen & Hyvarinen (1983) found similar sperm densities in perch, ranging from 37 Â 10 9 to 127 Â 10 9 sperm ml ÿ1 , but without specifying the M of the examined fish. As body mass to milt volume ratio is subject to annual variation (P. Compared to other fish species (Piironen & Hyvarinen, 1983;Stockley et al, 1996;Mylonas et al, 2003;Rainis et al, 2003;Mansour et al, 2004), the average sperm density in perch is high and the variation between males is considerably large. Sperm density in externally fertilizing fish has been shown to be generally higher than in mammals or other internal fertilizers (Stockley et al, 1997;Petersen & Warner, 1998;Byrne et al, 2002).…”

Thyroxine-induced alterations in the testis and seminal vesicles of air-breathing catfish, Clarias gariepinus

“…Based on these results, it is possible to assume that the normal levels of T and 11-KT may be necessary for maintaining SV function. The SV fluid is important in maintaining sperm motility, viability and some pheromonal activity (Mansour et al 2004). Hence, the reduction of SV fluid may have implications on sperm viability and volume during spawning.…”