Abstract: 【Objective】The study aimed to investigate the effects and mechanisms of soy protein hydrolysate (SPH) on the appetite in mice and provide new frame work guidelines for strategies towards manipulating feed intake in pigs.【Method】In this study, pepsin was used to hydrolyze soy protein to produce SPH. Firstly, the effects on short-term feed intake and the expressions of duodenal peptide sensing receptors calcium sensing receptor (CaSR), G protein-coupled receptor 93 (GPR9)3 and oligopeptide transporter 1 (PepT1) were investigated by intragastrically different concentrations of SPH. Based on this, the CaSR inhibitor NPS2143 and the peripheral cholecystokinin-1 receptor (CCK-1R) inhibitor Devazepide were intraperitoneally injected , respectively, to investigate whether SPH inhibited feed intake by the CASR-CCK-CCK-1R-hypothalamus pathway.【Result】The amount of 1.5g·kg^-1 SPH reduced the 0-1h feed intake (P<0.05), and increased the CaSR expression (P<0.05). Compared with SPH group, the feed intake of SPH + NPS2143 group were increased at 0-1h, and the plasma CCK levels were decreased, and there were no differences from the control group (0.05) (P<0.05), while the effects disappeared in SPH+Devazepide group. However, SPH had no effect on the small intestine transit rate or the expression of the hypothalamic food-promoting factors neuropeptide Y (NPY) and agoutirelated peptide (AgRP).【Conclusion】CaSR mediates SPH to promote CCK secretion, and through the peripheral CCK-1 receptor to delay gastric emptying rate and improve the expression of hypothalamic anorexia nerve factor POMC to suppress appetite.

Key words: soy protein hydrolysate, food intake, calcium sensing receptor, cholecystokinin, CCK-1 receptor, hypothalam