Effect Of Two Different Types Of Diets On Fatty Acid Metabolism Of Dairy Cow

This study was carried out to investage the effect of two different types of dietson blood fatty acid profile, milk fatty acid profile, uptake of fatty acids in mammarygland, blood parameters and fatty acids metabolize in mammary gland.Experiment Ⅰ: Our experiment was conducted to investage two different types ofdiets on blood fatty acid profile, milk fatty acid profile, uptake of fatty acids inmammary gland, blood parameters of dairy cow. Twenty China lactating Holsteindairy cows were randomly assigned to two treatments, with similar body weight, milkyield and days in milk. The two treatments were corn straw treatment (CS) and mixedforage treatment (MF). The trial lasted6weeks. The first2weeks was preliminaryperiod, followed by a4-week sample collecting period. Compared with CS treatment,cows fed MF diet had positive effects (P<0.05) on milk fat and milk yield. The resultsshowed that MF significantly increased the contents of C14:0(P=0.02), C16:1(P=0.02), C18:3(P<0.01) and PUFA (P=0.03) in the blood. But the content ofc9c12C18:2in MF was significantly lower than the CS (P<0.01). The contents ofC18:0(P=0.02), C18:3(P<0.01), C20:0(P=0.02), UFA(P=0.03), MUFA(P<0.01)、MCFA(P=0.04) in milk fat of MF were higher than CS. And the contents of C14:1(P=0.03), c9C18:1(P=0.02), C23:0(P<0.01), UFA (P=0.03), MUFA (P<0.01), MCFA(P=0.03) in milk fat of CS were higher than MF. The MF increased content of NEFAin plasma (P<0.01). These results indicated that CS increased the oleic acid in milk,which can improve the plasticity and processing characteristic of milk fat. Thelinolenic acid of milk fat decreased in CS group. The better application of corn silagewas to consider adding linolenic acid-rich feed materials such as linseed oil toincrease polyunsaturated fatty acid in milk fat, and to improve milk quality in theproduction.Experiment Ⅱ: This part was desgined to investage mRNA expression oflipogenic genes of lipogenic genes response to cows fed different types of diets. Weselected Ten Chinese lactating Holstein dairy cows for this study. Cows wererandomly assigned to two treatments, with similar body weight, milk yield and day inmilk. The other concrete way was similar with the part1. The results showed that, theMF groups upregulated the mRNA expression of CD36, FABP4, AGPAT6, GPAM andPPARG (P<0.05), but there is nodifferent between the mRNA expression ofACSL1,ACSS2, FABP3, FASN, ACACA, SCD, DGAT1, DGAT2, SREBF1,PPARGC1A and SCAP (P<0.05). Compared to CS treatment, cows fed MF diet significantly increasedThe MF treatment have important effects on lipid metabolism through the regulationof PPARG, included the pathway of long chain fatty acids utilization (uptake,trafficking and activation), and TAG synthesis.