Transcriptome analysis of Clarias magur brain and gonads suggests neuro-endocrine inhibition of milt release from captive GnRH-induced males

Abstract

Transcriptome analysis of Clarias magur brain and gonads at preparatory, mature, 6 and 16 h post-GnRH injection (hpi) stages yielded 9.5 GB data with 39,738 contigs. Sequences of 45 reproductive genes were identified for the first time in C. magur along with unique and differentially expressed genes. The expression of 20 genes was validated by qRT-PCR. Upregulation of Cyp11A1, Cyp17A1 and FTZF1 genes in the 16hpi testis accompanied by the 17β-HSD3 expression indicates testosterone (T) synthesis in response to LH surge, while reduced expression of CYP11B1 suggests a high T: 11-KT ratio. It is evident by the gene expression analysis that the inhibitory neurotransmitter GABA, altered T: 11-KT, increased testicular bile acids, and oxytocin-like neuropeptide in the male brain, appear to be involved in arresting the pulsatile motion of testicular smooth muscles. The work generates important leads for an effective induced breeding strategy for silurid catfish.