Abstract
Dietary lipid sources critically influence growth, health, and muscle quality in Chinese mitten crab (Eriocheir sinensis), yet how high oleic acid diet (HOA) regulates intramuscular nutrient deposition remains unclear. Here, a 10-week feeding trial compared isonitrogenous and isoenergetic diets, in which soybean oil was replaced with high-oleic peanut oil. HOA significantly improved weight gain, specific growth rate, and protein efficiency ratio, without affecting survival, hepatosomatic index (HSI), or gonadosomatic index (GSI). HOA enhanced antioxidant capacity by increasing catalase activity and reducing malondialdehyde, while key non-specific immune enzymes were unchanged. In muscle, HOA did not increase intramuscular oleic acid (OA) content but reduced linoleic acid and upregulated genes involved in fatty acid transport and β-oxidation. HOA also shifted free amino acids (higher glutamate and lysine; lower proline) without significant transcriptional upregulation of the mechanistic target of rapamycin (mTOR) pathway or changing total protein. Multi-omics analyses indicated altered nucleotide/purine pathways and pronounced glycerophospholipid remodeling, identifying discriminatory lipid species. Overall, oleic-acid-rich lipids promote growth and antioxidant defense while reprogramming muscle lipid metabolism, supporting their targeted use to optimize crab muscle quality.