Growth Performance, Digestive Capacity, and Transcriptomic Analysis of Hybrid Offspring from Mastacembelus armatus and Mastacembelus favus

Hybrid breeding is a crucial approach in aquaculture to enhance the production performance of stocks. This study investigated the hybrid offspring resulting from the cross between zig-zag eel (Mastacembelus armatus) and tire track eel (Mastacembelus favus), systematically evaluating the manifestation of heterosis. Results demonstrated that the hybrid group exhibits significantly superior growth performance and environmental adaptability compared to both parental populations. Physiological analyses revealed that hybrid individuals possess distinct advantages in key physiological indices, including digestive enzyme activity and intestinal tissue structure. Liver transcriptome sequencing identified that the majority of differentially expressed genes (DEGs) in the hybrid offspring display non-additive expression patterns. These DEGs were significantly enriched in critical pathways associated with growth hormone synthesis, insulin secretion, and lipid metabolism. By integrating evidence from phenotypic characteristics, physiological indicators, to molecular mechanisms, this study provides a systematic elucidation of the foundation underlying heterosis in these hybrids, offering substantial theoretical insights and practical guidance for the elite breeding of the zig-zag eel and related species.