Abstract: There is a significant sex difference in the growth of yellow catfish (Pelteobagrus fulvidraco) at the same age which shows that males are longer in length and heavier in weight than females. mTOR (mechanistic target of rapamycin kinase) signaling pathway plays an important role in cell growth, development and protein synthesis. In order to understand the correlation between the nutritional growth mechanism of yellow catfish and the mTOR signaling pathway, this study firstly analyzed the muscle nutrient composition of female and male yellow catfish in the aspects of physiology and biochemistry. The results showed that the nutritional quality of female yellow catfish muscle was better than that of the wild female yellow catfish in terms of mineral elements, amino acid composition, protein evaluation and fatty acid quality, while there was little difference in water, crude protein and crude fat content between them. Quantitative real-time PCR (qRT-PCR) analysis was conducted for the major genes of mTOR signaling pathway. The results showed that the expressions of AKT serine/threonine kinase 1 (AKT1), AKT serine/threonine kinase 2 (AKT2), AKT serine/threonine kinase 3 (AKT3), mTOR, ribosomal protein S6 kinase B1 (S6KA), ribosomal protein S6 kinase B2 (S6KB), eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) in muscle, liver, kidney and heart tissues of male yellow catfish were significantly higher than those of female. This may be related to the growth differences of female and male yellow catfish. These results provide an experimental basis for further exploring the molecular mechanism of sexual growth difference of yellow catfish.
Key words: Pelteobagrus fulvidraco; nutritional composition; growth difference; gene expression analysis; mTOR signaling pathway
（Acta Laser Biology Sinica, 2023, 32(1): 026-035）