Sex steroids in diploid and triploid gibel carp (Carassius gibelio) of both sexes in different phases of the reproductive cycle

• Published in: Animal reproduction science 2022-09, Vol.244, p.107053-107053, Article 107053
• Main Authors: Przybył, Anna, Juchno, Dorota, Przybylski, Mirosław, Leska, Anna, Nowosad, Joanna, Kucharczyk, Dariusz, Boroń, Alicja
• Format: Article
• Language: English
• Subjects: 11-ketotestosterone; 17ß-estradiol; animal reproduction; Carassius gibelio; diploidy; drainage; enzyme immunoassays; gonadosomatic index; Gynogenesis; histology; invasive species; oocytes; Polyploidy; rivers; Testosterone; Triploid males; triploidy
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2022.107053

The changes in concentrations of 17ß-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT) in the gonads and plasma of diploid and triploid gibel carp (Carassius gibelio) from the Siemianowka Reservoir, the Vistula River drainage were quantified and compared using an enzyme immunoassay. The phase of gonad maturity was based on histological analysis and the gonadosomatic index. All fish had properly developed gonads in the pre-spawning, spawning and late spawning phases of the reproductive cycle in the fish collected in April, June and October, respectively. Diploid and triploid females and males did not differ in mean GSI in all reproductive phases. In October, ovaries of most females contained vitellogenic oocytes, testes had large numbers of spermatozoa. The hormone concentrations in both tissues depended mainly on the reproductive phase, but not on ploidy. The patterns of changes in E2 concentrations was similar in females and males. In the pre-spawning phase, diploid and triploid females showed differences in the concentrations of 11-KT in gonads and plasma, and T in plasma. Diploid males differed in pattern of T concentrations in gonads and plasma, while all males showed a similar pattern of 11-KT plasma concentrations. Spermatozoa observed in triploid males suggest that they participate in reproduction. Gibel carps, regardless of ploidy, had an extended period of reproduction, which makes this invasive species a potentially greater threat to native ichthyofauna. The sex androgen concentrations that differed between 2 n and 3 n females could be physiological factors potentially contributing to the coexistence of gynogenetic C. gibelio females and sexual diploids. •Diploid and triploid C. gibelio females and males have similar reproductive abilities.•Spermatozoa observed in triploid males suggest that they participate in reproduction.•Sex androgen levels may contribute to the coexistence of gynogenetic C. gibelio females and sexually reproducing diploids.•A protracted spawning period enhances the threat of C. gibelio to native fishes.