title: Spermatogenesis and related plasma androgen and progestin level in wild male golden mahseer, Tor putitora (Hamilton, 1822), during the spawning season.
abstract: Testicular development and plasma levels of sex steroid [11-ketotestosterone (11-KT), testosterone (T) and 17,20β-dihydoxy-4-pregnen-3-one (17,20β-P)] were studied for the first time in wild golden mahseer, Tor putitora. Testicular development was investigated by macroscopic observation and histology of the gonads, whereas steroids were measured by enzyme-linked immunosorbent assay. Based on macroscopic observation and germ cell types present in gonad histology, the testes of T. putitora were divided into five developmental stages: immature [stage I; spermatogonia (SPG)], early spermatogenesis [stage II; SPG and spermatocytes (SPC)], late spermatogenesis [stage III; SPG, SPC, spermatids (SPD) and spermatozoa (SPZ)], spermiation (stage IV; SPZ) and post-spawning (stage V; SPG, SPD and SPZ). During the stage I of the testes, the lowest levels of plasma sex steroid and gonadosomatic index (I G) were recorded. The highest plasma level of T was 0.89 ± 0.09 ng/mL and 11-KT was 4.23 ± 0.54 ng/mL, which was during the stage III and IV, respectively. The peak in 11-KT was coincident with the peak in I G (1.65 ± 0.12 %). The lowest T and 11-KT levels were 0.25 ± 0.02 ng/mL and 0.47 ± 0.09 ng/mL, respectively, which was at stage I. Plasma levels of 17,20β-P increased significantly at stage III (1.04 ± 0.06 ng/mL) and stage IV testes (1.28 ± 0.03 ng/mL) and then declined in post-spawned fish. This indicates that 17,20β-P could also be a possible maturation-inducing steroid in this fish. The condition factor (K) significantly decreased during the testicular development and was lowest at spermiation stage (0.53 ± 0.02 %). The proportion of running male peaked concomitantly with the appearance of stage IV testes. Presence of germ cells of different developmental stages indicates that T. putitora male is a multiple spawner, and the information generated here is important for developing a captive breeding, culture and conservation programs for this endangered coldwater Himalayan fish species.
authors.affiliation: Directorate of Coldwater Fisheries Research, Bhimtal, Nainital, 263 136, Uttarakhand, India, shahineetu@rediffmail.com.
authors.forename: Neetu
authors.initials: N
authors.lastname: Shahi
authors.forename: Sumanta Kumar
authors.initials: SK
authors.lastname: Mallik
authors.forename: Jyoti
authors.initials: J
authors.lastname: Pande
authors.forename: Partha
authors.initials: P
authors.lastname: Das
authors.forename: Atul Kumar
authors.initials: AK
authors.lastname: Singh
mesh_terms: D000728:Androgens / Q000097:blood*; D000818:Animals; D003530:Cyprinidae / Q000097:blood / Q000502:physiology*; D006908:Hydroxyprogesterones / Q000097:blood; D008297:Male; D011372:Progestins / Q000097:blood*; D012621:Seasons; D013091:Spermatogenesis; D013737:Testis / Q000254:growth & development*; D013739:Testosterone / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D000728:Androgens; D006908:Hydroxyprogesterones; D011372:Progestins; C007433:17,20-dihydroxy-4-pregnen-3-one; D013739:Testosterone; C003600:11-ketotestosterone