Effects Of Sodium Acetate On Production Performance And Lipid Metabolism Of Dairy Cows In The Late Peripartum Perio

This experiment investigated the effects of adding sodium acetate(NaAc)to the basal diet on the performance,blood biochemical parameters and lipid metabolism of cows in the late perinatal period.Twenty-four healthy Holstein cows with similar body condition,second births and similar due dates were randomly divided into two groups of 12 cows each.The test group was not added sodium acetate to the basal diet as the control group(Control,CON),and 8 mol sodium acetate was added to the basal diet daily as the treatment group(NaAc)for a 21-day trial period.The trials and results were as follows:First:To investigate the effect of adding NaAc to the basal diet on the productive performance of cows in the late periparturient period.The results were as follows:(1)Dietary addition of NaAc did not affect dry matter intake(DMI)and milk production of cows compared to the control group(P>0.05).(2)Dietary addition of NaAc significantly increased milk fat percentage compared to the control group(P<0.05).(3)NaAc significantly increased the content of octanoic acid(C8:0),pentadecenoic acid(C15:1),and cis-docosahexaenoic acid(C22:2)in milk compared with the control(P<0.05);however,it also significantly decreased the content of butanoic acid(C4:0),trans-linoleic acid(C18:2n6t),γ-linolenic acid(C18:3n6),cis-eicosatrienoic acid(C20:3n6),and eicosapentaenoic acid(C20:5)(P<0.05).Second:To investigate the effect of NaAc addition to the basal diet on blood biochemical indices of cows in the late peripartum period.The results were as follows:(1)The addition of NaAc to the diet significantly increased plasma uric acid(UA)levels compared to the control group(P<0.05).(2)Dietary supplementation of NaAc significantly increased the plasma levels of total cholesterol(TC)and high density lipoprotein cholesterol(HDL-C)compared with the control group(P<0.05),and no significant effect on the levels of non-esterified fatty acid(NEFA)and β-hydroxybutyric acid(BHBA)(P>0.05).(3)The addition of NaAc to the diet significantly increased the plasma levels of IgA and total antioxidant(TAOC)in periparturient cows compared to the control group(P<0.05).(4)Dietary addition of NaAc significantly reduced the levels of octanoic acid(C8:0),heptadecenoic acid(C17:1),transoleic acid(C18:1n9t),and monounsaturated fatty acids(MUFA)in blood(P<0.05)and significantly increased the level of docosahexaenoic acid(C22:6n3)compared to the control group.Third:To investigate the effect of NaAc addition to the diet on adipose tissue fat metabolism in late periparturient cows.(1)Dietary addition of NaAc significantly increased TG levels in the adipose tissue of the rump of late periparturient cows compared to the control group(P<0.05).(2)The addition of NaAc to the diet significantly increased the red fluorescence intensity of adipocyte periplasmic lipid droplet protein Perilipin-1 in the adipose tissue of cows in the late periparturient period compared with the control group(P<0.05).(3)The addition of NaAc to the diet significantly promoted lipid synthesis compared to the control group(P<0.05).(4)Dietary addition of NaAc significantly increased the mRNA expression of ACCα,a key rate-limiting enzyme for fatty acid ab initio synthesis,FAS and SCD1 genes,a key gene in lipid synthesis process,and Perilipin-1 gene,a periplasmic lipid droplet protein gene in adipocytes(P<0.05)and the protein expression of FAS and Perilipin-1 compared with the control group.In conclusion,dietary supplementation of NaAc significantly increased milk fat rate and reduced blood fat content,and also improved liver and kidney function,inhibited excessive fat decomposition and promoted fat synthesis in cows,thus alleviating the metabolic disorders caused by NEB and maintaining the dynamic balance of fat metabolism.