Multi-omics reveals glycolipid metabolism processes during the early development of largemouth bass (Micropterus salmoides)

The largemouth bass (Micropterus salmoides) is one of the most valuable freshwater farmed fish in China, whose production involves a lot of energy consumption. However, the genetic regulation of energy metabolism in largemouth bass early development remains unclear. Herein, combined transcriptome and metabolome analyses were carried out for six early developmental stages: blastocyst, gastrulation, hatching, 1 day post-hatching (dph), 2 dph and 3 dph. Early embryos’ yolk and oil droplet diameters decreased significantly with embryonic development (P < 0.05). A total of 853.16 Gb of clean data was generated in RNA-sequencing, and the Q30 quality score was 96.72%. The majority of the 17,847 differentially expressed genes (DEGs) were related to glycolipid metabolic pathways (steroid biosynthesis, butanoate metabolism and pentose and glucuronate interconversion pathways). In the metabolomics analyses, 2,152 differential metabolites (DEMs) were identified at the early developmental stages. The pathway analyses indicated that these DEMs were involved in starch and sucrose metabolism, carbohydrate digestion and absorption, glycerophospholipid metabolism and glyoxylate and dicarboxylate metabolism pathways. Additionally, the conjoint analysis revealed that several key genes, such as pld, gpcpd, etnk1, lypla2, lcat and gpat were altered their expression levels, thereby affecting lecithin, glycerol-1-phosphate, glycerophosphocholine, ethanolamine and 1-acyl-sn-glycero-3-phosphocholine metabolism. The findings shed new light on the mechanisms of glycolipid metabolism during the early development of largemouth bass.