The social status of the male Nile tilapia (Oreochromis niloticus) influences testis structure and gene expression

Abstract

Dominant and territorial behaviour are known social phenomena in cichlids and social stress influences reproduction and growth. The gonadotropic hormones trigger spermatogenesis and subordinate males have typically lower levels of gonadotropins than dominant males. In this study, we compared testis morphology and gene expression of dominant and subordinate Nile tilapia males (d-and s-males) in socially stable communities. The d-males had the highest gonadosomatic index but they were not the largest animals in the majority of studied cases. Long-term d-males showed large groups of Leydig cells and hyperplasia of the tunica albuginea due to numerous cytochrome-P450-11b-hydroxylase (Cyp11b) expressing myoid cells. Increased Cyp11b expression in d-males was reflected by elevated 11-ketotestosterone plasma values. However, immunofluorescence microscopy and expression analysis of selected genes revealed that most s-males conserved their capability for spermatogenesis and are, therefore, ready for reproduction when the social environment changes. Moreover, in s-males gene expression analysis by quantitative RT-PCR showed increased transcript levels for germ line-specific genes (vasa, sox2 and dmc1) and Sertoli-specific genes (amh, amhrII and dmrt1) whereas gene expression of key factors for steroid production (sf1 and cyp11b) were reduced. The Nile tilapia is a promising model to study social cues and gonadotropic signals on testis development in vertebrates.

An ex vivo Approach to Study Hormonal Control of Spermatogenesis in the Teleost Oreochromis niloticus

“…The primary antibodies used ( Table 1) are not derived from Nile tilapia proteins directly. The specificity of the anti-PCNAand anti-Vasa-antibodies was already shown in our previous publications for testis and ovary of Nile tilapia (34,40). The used PCNA antibody (PC10, catalog number MAB424, LOT 1766464) is a commercial mouse monoclonal antibody against the rat-PCNA protein and is well-established in a broad range of species in the animal kingdom from vertebrates to invertebrates.…”

Vgll3 and the Hippo pathway are regulated in Sertoli cells upon entry and during puberty in Atlantic salmon testis

“…For the male fish, pubertal stages were determined using 11-ketotestosterone (11-KT), GSI and histology. To provide quantitative measures for proliferation and degree of immaturity in testis samples, pcna 43 , 44 and amh 45 expression were measured, respectively (Supplementary Fig. S1 ).…”

Validation of Reference Genes for Real-Time PCR of Reproductive System in the Black Tiger Shrimp

“…japonica ) [61], Arabidopsis thaliana [62], and yeast [63]. It was also used as a gene marker for particular purposes; for example, for spermatocyte-specific gene for study the role of sumoylation in vivo in mice and mouse [64], for comparing gene expression profile of TOPAZ1 , which is potential marker for germ cell development [65], and for study of social status and gonadotropic signals on testis development in Nile tilapia ( Oreochromis niloticus ) [66]. Moreover, Dmc1 was also discovered in testis cDNA library of Crustacea, mitten crab ( Eriocheir sinensis ) [67], and P. monodon [26].…”