Seminal vesicle and testis secretions in Heteropneustes fossilis (Bloch): composition and effects on sperm motility and fertilization

In spawning catfish Heteropneustes fossilis, seminal vesicle (SV) plasma (S VP), testicular plasma (TP) and blood plasma (BP) all showed considerable d ifferences in physical and chemical characteristics. SVP is more viscous (4 .61 +/- 0.08 centipoise). and its specific gravity (1.06 +/- 0.003) and osm olality (277.4 +/- 8.32 m osmol kg(-1)) are significantly higher than BP an d TP. SVP has a near neutral pH (6.99 +/- 0.07). BP is slightly basic and T P is slightly acidic. SVP has significantly higher concentrations of Na+(13 5.64 +/- 15.90 mmol l(-1)), Ca2+(19.80 +/- 0.60 mmol l(-1)), Mg2+(1.81 +/- 0.08 mmol l(-1)) and Cu2+(0.18 +/- 0.02 mmol l(-1)), proteins (11.50 +/- 0. 80 g l(-1)) and hexosamines (694.68 +/- 91.25 mg l(-1)) than TP, while the concentrations of K+(15.30 +/- 1.30 mmol l(-1)), Zn2+(0.10 +/- 0.02 mmol l( -1)), glucose (76.18 +/- 24.29 mg l(-1)), fructose (333.33 +/- 45.64 mg l(- 1)). lipids tin mg l(-1): phospholipids (PL), 112.84 +/- 18.40; free choles terol (FC), 109.99 +/- 15.45; esterified cholesterol(EC), 170.72 +/- 10.56) and glycosidases (mu mol mg protein(-1) h(-1): beta -glucuronidase. 7.20 /- 0.56; beta -N-acetylglucosaminidase, 83.00 +/- 12.19) are similar to TP. Dilution of SV fluid at greater than or equal to 400 times with distilled w ater activated motility of spermatozoa and the motility rate increased with the dilution factor. The duration of motility increased with motility rate up to 600-700 times dilution, but then on, declined sharply. A similar mot ility behavior was found for TM with the addition of SVP. The fertilization efficiency was evaluated in the presence of SVP or SV fluid (SVF). The add ition of freshly collected SVF and SVP increased the fertilization ability of TM from 72.0% to 95.6% and 87.8%, respectively. Pure SVF and SVP resulte d in only 29.6% and 0.0% fertilization, respectively. Heat denaturing aboli shed the stimulatory effect of SVF or SVP. Storage of spermatozoa in SVF at 4 degreesC after dilution with ringer solution (1:4) displayed varied effe cts on fertilization of eggs: in SVF groups fertilization decreased minimal ly (21.7% on day 12). but in TM group, it decreased more significantly with the time of storage. (C) 2001 Elsevier Science B.V. All rights reserved.