Regulatory Effect Of Ellagic Acid On Oxidative Damage Of Muscle In Piglets

The poor growth performance and high mortality of piglets induced by oxidative stress has restricted the development of the swine industry in China for a long time.Ellagic acid(EA),as a natural antioxidant in plants,has been proved to have a positive effect on alleviated oxidative stress in animals.Therefore,this study aimed to investigate the effect of EA on the muscle oxidative injury in weaning piglets.Twenty-four healthy of 21-day-old weaned piglets(Duroc×Landrace×Yorkshire)with an average initial body weight(BW)were randomly assigned into three treatments with 8 pens/treatment(1 piglets/pen).Treatments were as follows: 1)Control group(Basal diet);2)PQ group(Basal diet + Paraquat);3)PQ + EA group(Basal diet + 0.01% EA).Piglets were intraperitoneally injected with 4 mg/kg(BW)PQ or equal volume of saline on day 18 of the experiment.At day 21 of the experiment,piglets were slaughtered after blood sampling and collect longissimus dorsi muscle samples.The main results were shown as follows:(1)Dietary supplementation with 0.01% EA could improve the growth restriction of piglets induced by oxidative stress,but there was no significantly difference in serum biochemistry.After intraperitoneal injection of 4 mg/kg PQ,the body weight of piglets in control group and PQ + EA group were increased(P < 0.05),but there was no significantly change in body weight of piglets in PQ group(P > 0.05).Compared with the control group,serum ALB concentration in PQ group was decreased(P < 0.05).There was no significantly difference in serum biochemistry between PQ group and PQ + EA group(P > 0.05).(2)Dietary supplementation with 0.01% EA significantly enhanced antioxidant capacity in serum and muscle,and muscle myogenic gene expression of oxidative stress piglets.Compared with the control group,PQ injection significantly reduced the activity of TAOC and concentration of GPX in serum(P < 0.05).Compared with the PQ group,EA treatment significantly increased serum TAOC activity and GPX concentration(P < 0.05).Meanwhile,the activities of SOD and GSH in muscle of PQ group were lower than those in control and PQ + EA groups(P < 0.05).Compared with the PQ group,EA treatment significantly increased the relative gene expression of Myod in muscle(P < 0.05).(3)Dietary supplementation with 0.01% EA significantly increased the amino acid levels in the serum and muscle of oxidative stress piglets.The serum contents of Asp,Ser,Gly,Ile and Phe of piglets in PQ group were lower than those in the control group(P < 0.05).The serum Asp content in PQ + EA group was higher than that in the PQ group(P < 0.05).In muscle,compared with the control group,the muscle concentrations of Tau,Thr,Glu,Cys and Pro of piglets in PQ group were lower than those in the control group(P < 0.05),while Orn and Lys concentrations were increased(P < 0.05).Compared with the PQ group,the muscle contents of Tau,Thr,Glu,Ieu,Leu,Phe and Pro of piglets in PQ + EA group were higher than those in the PQ group(P < 0.05),while the contents of Lys and Orn were decreased(P < 0.05).(4)Dietary supplementation with 0.01% EA could regulate the amino acid transport and metabolism of oxidative stress piglets.Compared with the control group,PQ injection reduced the relative m RNA levels of Slc1a1 and Slc25a2 in muscle(P < 0.05),but increased the relative m RNA levels of Scl6a6 and Odc in muscle(P < 0.05).Compared with the PQ group,EA treatment significantly increased the relative gene expression levels of Slc1a1 and Scl6a6(P < 0.05),but decreased the relative gene expression levels of Prodh,Oat and Odc in muscle(P < 0.05).Meanwhile,EA treatment could stimulate phosphorylation of m TOR-4EBP1 signaling pathway to regulate muscle proliferation and promote muscle injury repair.In conclusion,dietary supplementation of 0.01% EA could effectively improve the growth inhibition induced by oxidative stress in piglets,and increase the antioxidant defense ability in serum and muscle,as well as alleviate the oxidative injury in muscle by up-regulating the expression of myogenic factors.EA was involved in regulating the amino acid transport and metabolism in muscle of oxidative stress piglets.EA might promote the synthesis of GSH by increasing the levels of Glu and Cys in muscle.EA could also promote protein synthesis and cell proliferation by activating mTORC1-4EBP1 signaling pathway in muscle.