Three DPP-IV inhibitory peptides from Antarctic krill protein hydrolysate improve glucose levels in the zebrafish model of diabetes

Abstract Ala-Pro (AP), Ile-Pro-Ala (IPA) and Ile-Pro-Ala-Val-Phe (IPAVF) as DPP-IV inhibitory peptides were purified from Antarctic krill protein hydrolysate (AKH). Diabetic zebrafish model was rapidly induced with combination of high glucose immersing and cholesterol diet for evaluation the three DPP-IV inhibitory peptides activity. Physiochemical indexes including DPP-IV activity, glucose, triglyceride and cholesterol; the relative gene (insa, glucagon and pck1) expressions levels were detected. The results showed that after 15 days of peptides treatment, the physiochemical index levels of peptide groups were significantly higher than that of negative control and showed dose-dependent effect. The insa gene expression level would be increased with the enhancement of peptide concentration, whereas gene expression levels of glucagon and pck1 would be decreased. These results indicated that three peptides all had hypoglycemic effects in different degree. It suggested the potential of AKH containing DPP-IV inhibitory peptides could be as functional food supplement to treat diabetes.