Effects Of Linoleic Acid And Oleic Acid On Milk Fat Synthesis In Bovine Mammary Epithelial Cell

This thesis aims to study effects of adding linoleic acid,oleic acid or the mixture of linoleic acid and oleic acid to bovine mammary gland epithelial cells on mammary epithelial cell proliferation activity,synthesis of triglycerides,and gene expressions of milk fat synthesis.This thesis includes two experiments.Exp 1.This work was studied effects of adding 100 μmol/L of linoleic acid,oleic acid or the mixture of linoleic acid and oleic acid on mammary epithelial cell proliferation activity,synthesis of triglycerides,and gene expressions of milk fat synthesis.The experiment adopted single-factor completely random design.Treatments were control group,treatmentⅠ group(+ oleic acid),treatment Ⅱ group(+ linoleic acid),and treatment Ⅲ group(+ oleic acid and linoleic acid)respectively.The results showed that:(1)Cell proliferation activity was increased significantly by adding fatty acids compared with control group(p<0.05),while treatment Ⅲ lower than treatment Ⅱ and treatment Ⅰ.(2)Triglycerides synthesis amount increased in treatment Ⅰ group and treatment Ⅱ group significantly(p<0.05),whereas there was no change in treatment Ⅲ(p>0.05).(3)ACACA gene expression was up regulated significantly by treatment Ⅰ,and was down regulated by treatment Ⅱ and treatment Ⅲ(p<0.05).Expressions of FASN,SCD,PPARG,SREBF1,DGAT1,LPIN1,FABP3,ACSL1,CD36 were down regulated by treatment Ⅲ significantly(p<0.05).AGPAT6 gene expression was up regulated by all fatty acids adding treatments.Exp 2.Based on the results of Exp 1,this work studied effects of adding 100 μmol/L of oleic acid mixture with increasing amounts of linoleic acid on mammary epithelial cell proliferation activity,synthesis of triglycerides,and gene expressions of milk fat synthesis.Treatments were control group or adding 100 μmol/L of oleic acid with increasing amounts of linoleic acid groups,those were 25 μmol/L,50 μmol/L,75 μmol/L μmol/L,or 150μmol/L.The test results showed that:(4)Compared with control group,adding 100 μmol/L of oleic acid and 25μmol/L of linoleic acid significantly decreased cell proliferation activity(p<0.05).There is no significantly difference between other treatmens.(5)The relative triglyceride contents did not show significantly difference among treatments.(6)The m RNA expression of ACACA,SCD,PPARG,SREBF1,DGAT1,GPAM,FABP3 and ACSL1 were down-regulated in all the treatments compared with the control(p<0.05).In conclusion,fixed the amount of supplemental oleic acid and change the amount of supplemental linoleic acid would significantly affect the genes involved in milk fat synthesis expression.