Modulating Mechanism Of Soybean Bioactive Peptides (SBP) On Cholesterol Metabolism And Yolk Pigmentation In Laying Hens

This study focused on the effects of soybean bioactive peptides (SBP) on productive performance, yolk cholesterol and yolk color in laying hens. Further more, the mechanism of this effects was investigated on aspects of metabolisms of bile acids and cholesterol. Experiment 1: Study on the emulsifying properties of SBPIn contrast with soy protein isolate, the emulsification of soybean peptides was increased greatly. The tope emulsifying capacity was observed when hydrolysis degree(DH) value reached 10% with the enzymatic modification by B.subtilis. Experiment 2: Effects of SBP on production performance & yolk quality of hens.1) 378 Lohmann laying hens of 296-old-day were randomly allotted into 6 groups and 63 per groups. The 6 groups adopted an entirely random experiment designation of two factors (2x3) .dietary oil levels were 0 and 10g/kg, dietary SBP levels were 0, 120mg/kg and 180mg/kg. 2) 78 Lohmann laying hens of 296-old-day were randomly allotted into 6 groups and 63 per groups. The 6 groups adopted an entirely random experiment designation of two factors (2x3) .dietary oil levels were 0 and 10g/kg, DH of SBP were 0, DH=10% and DH=20%.The results were as follows: Supplementation of SBP decreased egg cholesterol effectively (P< 0.01). Laying hens fed diets supplemented with SBP and soy oil presented better values of RCF(P< 0.01) than with SBP or soy oil. Red value increased quickly (P<0.01), and Light value was decreased by all levels of peptides supplementation ( P<0.01). But yellow value was not modified. Experiment 3: Mechanism of the cholesterol-lowing activity and yolk color-increasing effects of SBP in laying hensIn experiment 2, conducted to test the influence of SBP on mechanism of bile and cholesterol in laying hens. The results were as follows:1) normally, SBP can decrease the level of blood lipid in laying hens slightly. But when the level of blood lipid was higher than normal level, SBP can decreased the lipid content of blood significantly ( P<0.01). The lipid content of blood decreased linearly with the amounts of SBP in the diets. 120mg/kg SBP significantly increased the level of thyroxine(P<0.05) and excretion of both fecal bile acids and fecal neutral cholesterol (P<0.05).2) It is possible That SBP decreased yolk cholesterol by increasing excretion of both fecal bile acids and fecal neutral cholesterol.3) SBP could increase the level of thyroxine. Potentially it can inhance the synthesis and secretion of bile acids, boost yolk pigmentation.