Sexual dimorphism in the texture properties of swim bladder of Nibea coibor and its molecular basis revealed by comparative transcriptome analysis

Abstract

Texture is an important factor determining the quality, acceptability of aquatic products to consumers. Swim bladder from croakers is a traditionally important and high-valued aquatic product in Asia. It was generally considered that swim bladder from male croaker has higher texture quality than those from female. Therefore, mono-sex breeding or nutritional regulation represent promising strategies for improving the texture quality and value of swim bladder in the aquaculture industry of croaker. However, no direct evidence has been reported and the molecular basis associated with the sexual difference in the texture properties remains unknown. Here, we investigated the sexual dimorphism in the texture traits of swim bladder of an important marine economic fish, Chu’s croaker (Nibea coibor) and its possible molecular mechanism by comparative transcriptome analysis. Results showed that the tested texture parameters (springiness, hardness, chewiness, shear force, etc.) of the swim bladder in male fish (MSB) were significantly higher than those in female (FSB). A total of 143 differentially expressed genes (DEGs) were acquired between sexes. GO and KEGG pathway enrichment analysis indicated that regulation of extracellular matrix component (ECM), ECM-receptor interaction and primary bile acid synthesis pathway may contribute to the sexual difference. Furthermore, 6 validated DEGs (tnc, gjc1, colgalt1, col12a1, cyp27a1, qpct) were demonstrated to be closely correlated with at least four texture traits. In conclusion, for the first time we demonstrated the sexual dimorphism in the texture traits of swim bladder and the result could provide potential molecular targets for regulating the texture quality of swim bladder of the Chu’s croaker during aquaculture practice.