Cottonseed meal protein hydrolysate stimulates feed intake and appetite in Chinese mitten crab, Eriocheir sinensis

One hundred and twenty crabs (initial weight: 51.32 ± 0.06 g) were fed three experimental diets with cottonseed meal protein hydrolysate (CPH) at 0, 6 and 12 g/kg for 60 days. The results showed that CPH0.6 diet significantly improved the 1-hr feed intake, protease activity and weight gain of crabs. In thoracic ganglia, 4E-binding protein (4E-BP) expression level of crab fed the diets containing CPH was significantly higher than CPH0 group. In cerebral ganglia, protein kinase B and 4E-BP expression levels of crab fed CPH0.6 diets were significantly lower than CPH0 group. In mid-intestine, target of rapamycin (TOR) relative expression level of crabs fed the diets containing CPH was significantly lower than CPH0 group. 4E-BP expression level showed an opposite pattern. In thoracic ganglia, cerebral ganglia and mid-intestine, leptin receptor expression level of crabs fed CPH0.6 diet was significantly lower than CPH0 group. Neuropeptide Y and neuropeptide Y receptor expression level of crab fed CPH0.6 diet was significantly higher than CPH0 group. In conclusion, our results indicated that dietary supplementation of 6 g/kg CPH could stimulate appetite and quicken feeding rate via the TOR signalling pathway.