Functional evaluation of a novel kisspeptin analogue on the reproduction of female goldfish

Abstract

Kisspeptin (kp) is a key regulator of reproduction, which stimulates sexual maturation and gametogenesis in mammals, amphibians, and teleosts. In the present study, to enhance the biological activity of kp10, a novel analog (referred to as M-kp10) was designed based on the endogenous goldfish variant, in which phenylalanine 6 was substituted by tryptophan and the N-terminus was acetylated. Compared with the native kp-10 and salmon gonadotropin-releasing hormone (GnRH3), the effect of M-kp10 on sexual hormones and reproductive indices as well as the expression of kiss1, cyp19a1, and kiss1ra genes in goldfish (Carassius auratus) was investigated. In practice, peptides were synthesized based on the standard Fmoc-solid-phase peptide synthesis and purified by employing RP-HPLC, followed by approving their structure using ESI-MS. The results showed that M-kp10 increased significantly 17,20β-DHP, LH, FSH and E2 as well as fecundity, hatching and fertilization percentages than the other peptides. Histological studies revealed that M-kp10 led to the faster growth of ovarian follicles compared to the kp-10 and GnRH3. The genes of cyp19a1, kiss1ra, and kiss1 were remarkably more expressed after treatment with M-kp10. In conclusion, the results indicated the superiority of M-kp10 over kp-10 in inducing sexual maturation and accelerating the percentage of fecundity, suggesting that M-kp10 could be a promising candidate for application in the artificial breeding of fish.

Cloning, Expression Analysis and SNP Screening of the kiss1 Gene in Male Schizothorax biddulphi

“…In sexually mature fish, kisspeptin treatment led to increased gonad weight and gonadosomatic index in some white bass ( Morone chrysops ) and striped bass ( Morone saxatilis ) [ 9 ]. The Kisspeptin system of teleosts generally consists of kiss genes ( kiss1 and kiss2 ) and kiss receptors ( kissr1 , kissr2, and kissr3 ) [ 10 , 11 ]. Most bony fishes, such as goldfish ( Carassius auratus ), zebrafish ( Danio rerio ), and medaka ( Oryzias latipes ), contain both the kiss1 and kiss2 genes [ 10 , 12 ].…”

“…The Kisspeptin system of teleosts generally consists of kiss genes ( kiss1 and kiss2 ) and kiss receptors ( kissr1 , kissr2, and kissr3 ) [ 10 , 11 ]. Most bony fishes, such as goldfish ( Carassius auratus ), zebrafish ( Danio rerio ), and medaka ( Oryzias latipes ), contain both the kiss1 and kiss2 genes [ 10 , 12 ]. In almost 20 fish species, only kiss2 can be found [ 13 , 14 ].…”