Hypocholesterolemic effect of karaya saponin in Japanese laying quails (Coturnix coturnix japonica)

The effect of karaya saponin supplementation on the serum and egg yolk cholesterol and fatty acid composition in egg yolk were investigated in Japanese quails. A total of 80 Japanese quails aged 5 weeks were equally divided into four groups of 20. Four levels (0, 25, 50 and 75 mg/kg feed) of karaya saponin were included in the basal diet and experiment was lasted for 6 weeks. The cholesterol fractions in the egg yolk and serum were measured by enzymatic assay, and the fatty acid composition in egg yolk was determined by gas chromatography. The results revealed that the supplementation of 75 mg/kg karaya saponin significantly reduced (p < 0.05) cholesterol and triglycerides concentration in serum and egg yolk. High-density lipoprotein-cholesterol was increased, low-density lipoprotein-cholesterol and the atherogenic index were decreased (p < 0.05) by the dietary supplementations. Hepatic cholesterol was reduced (p < 0.05) by the 25 mg/kg karaya saponin. A higher degree of yolk colour was improved (p < 0.05) when 75 mg/kg saponin was supplemented in the diet. The concentration of polyunsaturated fatty acids (PUFA) in egg yolk was increased (p < 0.05) in a dose-dependent manner in quails fed the supplemented diet than the control diet. The ratio of PUFA to saturated fatty acids in egg yolk was improved (p < 0.05) by 75 mg/kg feed karaya saponin-supplemented diet. Therefore, the dietary supplementation of 75 mg/kg karaya saponin may be a feasible means of producing quail eggs with lower cholesterol and higher PUFA content for health conscious consumers.