# Dietary supplementation of coconut meat modulates growth performance, nutritional composition, and internal regulation in Chinese mitten crab (Eriocheir sinensis)

## TL;DR

Adding coconut meat to the diet of Chinese mitten crabs improves their growth, nutritional quality, and internal regulation, especially in females.

## Contribution

This study identifies coconut meat as a functional feed ingredient that enhances nutritional and physiological traits in Chinese mitten crabs.

## Key findings

- Female crabs fed coconut-supplemented diets showed significantly higher condition factor values.
- Coconut supplementation increased lauric acid and PUFA levels in gonads of both male and female crabs.
- Transcriptomic analysis revealed thousands of differentially expressed genes linked to metabolism and development.

## Abstract

The Chinese mitten crab (Eriocheir sinensis) is a commercially important aquatic species valued for its high nutritional quality and desirable taste.

This study investigated the effects of dietary supplementation with 30% coconut meat (experimental), compared to a basal diet of fresh-frozen fish (control), on male and female crabs. Growth performance, amino acid and fatty acid profiles in muscle and gonadal tissues were analyzed, and transcriptomic sequencing was conducted to elucidate the underlying molecular mechanisms.

Results revealed a significantly higher CF values in females fed the coconut-supplemented diet (P < 0.05). Lauric acid (C12:0) content in gonads was significantly increased in the experimental group of male and female crabs, and female gonads also exhibited elevated polyunsaturated fatty acid (PUFA) levels (P < 0.05). In male crabs, muscle levels of the flavor-related amino acids glutamate, glycine, and alanine were significantly higher in the experimental group (P < 0.05). Furthermore, dietary coconut supplementation significantly enhanced overall antioxidant capacity, as indicated by improved GPx, CAT, and T-AOC values (P < 0.05). Transcriptome analysis highlighted 71 and 4,380 DEGs in experimental male and female crabs, respectively, relative to control group. KEGG enrichment analysis revealed that these DEGs were primarily involved in metabolic and developmental pathways, such as carbohydrate, lipid, and amino acid metabolism, Cell growth and death and endocrine. A total of 39 key DEGs were identified as central to the physiological responses induced by coconut supplementation. These findings provided a scientific basis for the use of coconut meal as a functional feed ingredient for Chinese mitten crab, and contributed to foundational knowledge for constructing gene regulatory networks related to nutritional quality in this species.