Selar (Selar crumenophthalmus) Fish Protein Hydrolysate Has an Antidiabetic Properties Possibly through GLP-1

Background : Enzymatic hydrolysis of fish protein using protease or fish protein hydrolysate can form bioactive peptides that has antidiabetes activity. One potential mechanism of fish protein hydrolysate in reducing blood glucose is through increased endogenous glucagon like peptide (GLP)-1 production. Tempeh is soy fermented food that has protease which is potential as biocatalyst in producing fish protein hydrolysate. Objective: To evaluate the antidiabetic properties of Selar (Selar crumenophthalmus) fish protein hydrolysate using tempeh protease as biocatalyst and duodenal gene expression of GLP-1. Methods: Selar fish protein isolate was digested for 8 hours at 37° C using crude tempeh protease. Diabetes mellitus was induced in rats by intraperitoneal injection of streptozotosin (65 mg/kg bw) and nicotinamide (230 mg/kg bw). Fish protein isolate and hydrolysate in dose of 300 mg/ bw and 500 mg/ bw were orally administered daily for 4 weeks. Blood was drawn for fasting serum glucose and lipid profile analysis. Total RNA were isolated from duodenum and quantitative real time PCR was performed to quantify mRNA expression of GLP-1. Data were analyzed using one way ANOVA and gene expression analysis were performed using Livak. Results and Discussion: There is a significant difference on fasting serum glucose, total cholesterol, triglyceride, LDLcholesterol, HDL-cholesterol and duodenal GLP-1 mRNA expression level between groups (p<0.05). The duodenal GLP1 mRNA expression was the highest in rats received hydrolyzed fish protein 500 mg/ bw.