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Effect of GnRHa injection on milt volume in recently stripped rainbow trout Oncorhynchus mykiss
Author(s) -
Heyrati Fatemeh Paykan,
Amiri Bagher Mojazi,
Dorafshan Salar
Publication year - 2010
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2010.02515.x
Subject(s) - milt , rainbow trout , sperm , biology , zoology , sperm motility , andrology , reproduction , endocrinology , medicine , fish <actinopterygii> , fishery , ecology , botany
In this study, the effect of gonadotropin‐releasing hormone agonist (GnRHa) injection on milt production in spent rainbow trout was investigated. On day 0, 25 newly matured male rainbow trout ( Oncorhynchus mykiss ) were stripped manually, and sperm quantity (vol: mL fish −1 ) and quality, spermatocrit (%), sperm count (cell mL −1 ), motile sperm percentage and motility duration (s) were evaluated. After stripping, fish were randomly divided into five groups: intact; sham (injected with propylene glycol as a hormone vehicle); and groups receiving 4, 8 or 16 μg kg −1 BW of [ d ‐Ala 6 Des‐Gly 10 ] mGnRHa. On day 7, the fish were stripped again and the same sperm characteristics as on day 0 were measured. At the beginning of the experiment, there were no significant differences in any of the sperm quantity characteristics between groups. On day 7, expressible milt volume was significantly reduced compared with day 0 ( P <0.05, t ‐test) in the intact and sham groups but milt quality remained the same ( P >0.05, t ‐test). The present study shows that GnRHa injection with a concentration as low as 4 μg kg −1 BW after first stripping could prevent a significant reduction in milt quantity collected 7 days later without any adverse effects on sperm quality.