Effects Of Dietary Eucommia Ulmoides Extract On Lipid Metabolism,Antioxidant Capacity And Meat Quality Of Pigs

This study examined the effects of dietary Eucommia ulmoides extract supplements on lipid metabolism,meat quality and antioxidant capacity in finishing pigs,so as to provide theoretical basis and technical support for the scientific application of Eucommia ulmoides extract in animal husbandry and the production of high quality pork.Design and grouping of the experiments: one hundred and forty-four “Duroc × Landrace× Yorkshire”(DLY)weaned piglets with an average initial weight of 10.11±0.03 kg was randomly allotted to four treatment groups,each with six replicates and six piglets per replicate.Each group of pigs was fed a basal diet(control group)or a diet supplemented with increasing levels of Eucommia ulmoides extract(0.1,0.2,or 0.3%),until the average body weight of pigs was about 115 kg.The results showed that:(1)Eucommia ulmoides extract increased the growth performance of pigs at 10-70 kg body weight;and dietary supplements of 0.1% Eucommia ulmoides extract significantly increased carcass weight(P<0.01)and carcass length(P<0.05),and 0.3% Eucommia ulmoides extract significantly increased Lean mass percentage(P<0.01),dressing percentage(P<0.01)and eye muscle area(P<0.05)were quadratically increased at first and then decreased with dietary Eucommia ulmoides extract supplemental level increasing;(2)Dietary supplements of 0.1% Eucommia ulmoides extract markedly decreased serum triglyceride(TG)(P<0.05)in finishing pigs.With the increase of dietary Eucommia ulmoides extract,serum very low density lipoprotein cholesterol(VLDL-C)levels(P<0.01)were quadratically decreased at first and then increased,and high density lipoprotein cholesterol(HDL-C),adiponectin(ADPN)and insulin-like growth factor-1(IGF-1)levels(P<0.01)were quadratically increased at first and then decreased;(3)With the increase of dietary Eucommia ulmoides extract,the activity of acetyl-Co A carboxylase(ACC)in backfat tissue,longissimus dorsi and biceps femoris of finishing pigs were quadratically decreased at first and then increased(P<0.01),while the activities of hormone-sensitive lipase(HSL)(P<0.01)and lipoprotein lipase(LPL)(P<0.01)quadratically increased at first and then decreased.The m RNA expression levels of key lipid reductionrelated genes HSL,triglyceride lipase(ATGL),Carnitine palmityl transferase1B(CPT1B),sterols regulate primary binding proteins-1c(SREBP-1c)and AMP-activated protein kinase-α(AMPK-α)in backfat tissue were notably increased at 0.1% and 0.2% levels of Eucommia ulmoides extract(P<0.05);(4)Histological examination showed that Eucommia ulmoides extract decreased the average cross-sectional area of adipocytes in the backfat tissue;(5)All three levels of Eucommia ulmoides extract dramatically upregulated(P<0.05)the protein expression levels of AMP-activated protein kinase α(p-AMPK-α)and Acetyl-Co A carboxylase(p-ACC)in backfat tissue of finishing pigs;(6)With the increase of dietary Eucommia ulmoides extract level,24 h redness value(a*)(P<0.05),45min(P<0.01)and 24 h p H value(P<0.05),inosinic acid(IMP)(P<0.05)and intramuscular fat(IMF)(P<0.01)content of longissimus dorsi muscle of finishing pigs quadratically increased at first and then decreased,while water loss rate and drip loss quadratically decreased at first and then decreased.Dietary supplementation of 0.2%Eucommia ulmoides extract significantly increased 45 min a * value(P<0.01),24 h p H value and the content of flavor and sweet amino acids of biceps femoris muscle(P<0.01),and significantly decreased its shear stress(P<0.01);(7)Dietary supplements of 0.2% Eucommia ulmoides extract significantly increased the content of flavor and sweet amino acids in muscle tissue(P<0.01),and enhance the activities of glutathione peroxidase(GSH-Px)(P<0.01)and superoxide dismutase(SOD)(P<0.05)in serum of finishing pigs.Dietary supplements the three levels of Eucommia ulmoides extract significantly up-regulated the m RNA expression levels of GSH-Px1 and SOD1 genes in the liver of finishing pigs(P<0.05),and dietary supplements of 0.1% and 0.2% Eucommia ulmoides extract could increase the m RNA expression level of nuclear factor E2-related factor2 gene(Nrf2)(P<0.05).In conclusion,Eucommia ulmoides extract increased the growth performance of pigs at10-70 kg body weight.Dietary supplements of 0.1% and 0.2% Eucommia ulmoides extract could improve the carcass traits of finishing pigs,and improve meat quality by increasing inosinic acid(IMP),flavor and sweet amino acids in pork.Eucommia ulmoides extract plays a lipid-lowering role by regulating the expression level of m RNA key genes in lipid metabolism and activating the AMPK-ACC signal pathway.It can enhance antioxidant activity and enhance the sensory quality of meat by increasing the activity of antioxidant enzymes and up-regulating the m RNA expression level of key genes.