# Enhanced Muscle Flavor in Male Chinese Mitten Crab (Eriocheir sinensis) Driven by Feed-Induced Reconfiguration of Intestinal Volatile Compounds

## TL;DR

This study shows that formulated feed can replace unsustainable trash fish in crab farming while improving the crabs' muscle flavor through changes in intestinal volatile compounds.

## Contribution

The study reveals that formulated feed alters intestinal volatiles, which transfer to muscle tissue and enhance flavor, offering a sustainable aquaculture strategy.

## Key findings

- Formulated feed increased sensory scores for sweetness and elevated levels of key aromatic and sweet volatile compounds in crab muscle.
- Intestinal volatile profiles strongly correlated with muscle flavor, indicating a transfer or transformation mechanism.
- Forty-eight volatiles were identified in intestinal chyme, with propanal and ethyl 2-methylpropanoate being major contributors to odor.

## Abstract

The aquaculture industry faces a critical challenge: replacing unsustainable iced trash fish (IF) with formulated feed (FF) without compromising the prized flavor of the Chinese mitten crab (Eriocheir sinensis). While the muscle flavor is paramount, its formation mechanism, particularly the potential transfer and deposition of volatile compounds from the intestinal chyme—a crucial flavor reservoir influenced by diet—remains poorly understood. This study investigated the dual impact of FF replacement on both the intestinal and muscle volatile profiles. Using advanced flavoromics (E-nose and GC–IMS), we discovered that FF significantly altered the intestinal volatile landscape, which in turn promoted the deposition of key sweet and aromatic compounds in the muscle, ultimately enhancing the overall sensory perception. Our findings reveal the gut’s role as a flavor modulation hub and demonstrate that formulated feed is not merely a sustainable alternative to finite marine resources but can actively steer flavor quality improvement. This provides a strategic, dual-benefit approach for crab aquaculture.

The traditional use of iced trash fish (IF) in Chinese mitten crab (Eriocheir sinensis) aquaculture raises sustainability concerns, but the shift to formulated feeds (FF—a commercial compound feed specifically designed to meet nutritional requirements by blending multiple ingredients and containing a balance of nutrients) is often hindered by fears of compromising its prized flavor. This study aimed to comprehensively evaluate whether a commercial formulated feed could effectively replace IF without diminishing flavor quality, hypothesizing that FF would alter the intestinal volatile profile, thereby influencing muscle flavor. Male crabs were fed either IF or FF for eight weeks. Muscle flavor was assessed using sensory evaluation, electronic nose (E-nose), and gas chromatography–ion mobility spectrometry (GC–IMS). Volatile compounds in intestinal chyme were also analyzed by GC–IMS to explore potential transfer mechanisms. The results indicated that crabs fed with FF showed higher sensory scores for sweetness. Additionally, the E-nose analysis revealed a clear separation trend between dietary groups and showed markedly higher sensor response values for aromatic compounds, biogenically derived compounds and Maillard reaction products, sulfur-containing organic compounds, aliphatic hydrocarbons, total volatile organic compounds, alcohols and organic solvents, and alkenes in the FF group compared to the IF group. Thirty-four volatiles were discovered in the muscle. Statistical analysis (independent samples t-test) showed that the FF group exhibited significantly elevated levels of 3-methylbutanal-M, propanal, (E)-2-pentenal, 2,3-pentanedione, and pentan-1-ol-M, whereas the IF group exhibited significantly elevated levels of 2-hexanone, dihydro-2(3H)-furanone, butyl acetate, ethyl 2-methylpropanoate, and phenol (p < 0.05). Fourty-eight volatiles were identified in the intestinal chyme. Propanal and ethyl 2-methylpropanoate were the dominant odor contributors based on correlation network analysis. Strong correlations were identified between the flavor profiles of intestinal chyme and muscle, suggesting a potential transfer or transformation of volatiles. This work provides a scientific basis for optimizing aquafeed formulations to ensure sustainable crab production without sacrificing end-flavor quality.