Effects Of Cordyceps Militaris Supplementation On Liver Damage And Skeletal Muscle Protein Metabolism Of Weaned Piglets

In modern intensive breeding systems,early weaning techniques are often used to improve the productivity of sows,thereby increasing the annual sow size and improving the utilization rate of breeding equipment,bringing more economic benefits to animal husbandry.However,early weaning can lead to immune stress in piglets,which is characterized by reduced feed availability,stunted growth and compromised immunity,liver damage and skeletal muscle protein breakdown,and in severe cases,death.Cordyceps militaris(CM)militaris is known as a valuable Chinese traditional medicine,which has anti-inflammatory,antioxidant and immunological functions,which can improve the growth performance and immune capacity of livestock and poultry,and has the effect of repairing tissue damage.Therefore,in this study,by adding Cordyceps militaris powder to the diet of weaned piglets,the effects of Cordyceps militaris on liver damage and skeletal muscle protein metabolism of weaned piglets and the mechanism of Cordyceps militaris regulating immune stress were investigated.A total of 144 Duroc × Landrace × large weaned piglets with the body weight of8.53±0.16 kg were randomly divided into 4 groups: NC group(basal diet),LPS group(basal diet + intraperitoneal injection of 300 μg/kg BW LPS),LPS+500 CM group(basal diet +500mg/kg CM+ intraperitoneal injection of 300 μg/kg BW LPS),LPS+1000 CM group(basal diet +1000 mg/kg CM+ intraperitoneal injection of 300μg/kg BW LPS).There were 6replicates per group and 6 pigs per replicate.Piglets were injected with LPS or equivalent normal saline 4 h before slaughter,and the experiment lasted for 28 days.During feeding,feed intake and health status were recorded every day and weighed regularly.4 h after injection,the samples of longissimus dorsi muscle and liver were taken.The main results of the experiment are as follows:1.Dietary Cordyceps militaris significantly increased the body weight of weaned piglets at 28 days of age(P < 0.05),and significantly decreased the spleen index(P < 0.05),indicating that Cordyceps militaris can improve the growth performance and immune performance of weaned piglets.In addition,Cordyceps militaris alleviated the LPS induced decrease of crude protein and total amino acid contents in Longissimus dorsi muscle(P <0.05).2.Cordyceps militaris increased the levels of ALT(P < 0.01),AST(P < 0.05),LDH(P< 0.01)and total bile acid(P < 0.01)in liver.RT-q PCR results showed that Cordyceps militaris significantly decreased the m RNA levels of TLR4,TRAF6,NF-κB and TNF-α in liver(P < 0.01),and inhibited the expressions of proliferation-related genes PCNA and apoptosis-related genes(Caspase-3,Caspase-8,Caspase-9).In addition,the contents of CAT,GSH-Px and T-SOD in diets supplemented with Cordyceps militaris were significantly increased(P < 0.01).These results indicate that dietary Cordyceps militaris can inhibit liver inflammation,excessive proliferation and apoptosis of liver cells,and improve the antioxidant capacity of liver.3.Cordyceps militaris down-regulated m RNA levels of TLR4(P < 0.05),My D88(P <0.05),TRAF6(P < 0.01),RIPK2(P < 0.05),NF-κB(P < 0.05)and TNF-α(P < 0.01)in longissimus dorsi muscle.At the same time,the levels of CAT,GSH-Px and T-SOD in longissimus dorsi muscle in LPS+500 CM and LPS+1000 CM groups were significantly higher than those in LPS group(P < 0.01),and the levels of MDA,LPO and T-AOC were significantly lower than those in LPS group(P < 0.01).Western blot results showed that dietary supplementation of Cordyceps militaris up-regulated the phosphorylation level of Akt(P < 0.05)and down-regulated the protein levels of MAFbx and Mu RF1(P < 0.05).These results indicate that Cordyceps militaris supplementation can inhibit inflammation,oxidative stress and protein decomposition in longissimus dorsi muscle of weaned piglets.In conclusion,dietary supplementation of Cordyceps militaris can improve the growth performance and immune performance of weaned piglets,and alleviate liver damage and skeletal muscle protein degradation of weaned piglets induced by LPS.Therefore,Cordyceps militaris provides a new idea for screening new feed additives and preventing immune stress of weaned piglets.