Effect of vegetable oil on ovarian steroidogenesis- A transcriptome approach to understand molecular mechanisms of hypothalamus pituitary and gonad axis (HPG) in Ompok bimaculatus

Ompok bimaculatus is a commercially important food fish of Northeast India. For higher production of this species, the molecular mechanisms underlying its reproductive physiology is an important aspect to study. Vegetable oils are rich in ω3 and ω6 fatty acids and fat-soluble vitamins, that enhance reproductive performances. In the present study, O. bimaculatus were first fed with vegetable oil at 3, 5, 7 and 9% in the diet. The best treatment was determined by the analysis of relative fecundity, fertilisation rate, Gonadosomatic Index (GSI) and Hepatosomatic Index (HIS). Comparative transcriptomics analysis of gonadal tissues between control and best treatment was done using Illumina NextSeq500. The bioinformatics analysis by Trinity v2.11.0 and edgeR v3.32.1 identified 36 DEGs related to reproduction, those were later validated by qPCR analysis. The Differentially Expressed Genes (DEGs) revealed, regulation of Hypothalamic-pituitary-gonadal axis (HPG) axis through retinoid signalling pathway, IGF pathway and folliculogenesis pathway, including inhibitory effects of dietary vegetable oil on fish gonadal maturation.