Effects Of Dietary Mulberry Leaves On The Growth Performance,Lipid Metabolism And Meat Quality In Finisher Pigs

China is the major producer of pork in the world,and the pork production counts to half of the world's total production.Pig industry consumes a large amount of protein feed,which is mainly dependent on imports in China.Mulberry leaves are rich of nutritional value,and their protein content are similar to alfalfa(about 16%),and enriched with a variety of bioactive components.More important,there are rich of mulberry leaf resources in China,thus the development of Mulberry leaves as a new type of protein resources alleviate the shortage of protein feed in China.In this study,72 finishing pigs(Duroc × Landrace × Yorkshire)with similar body weight and similar body conditions were randomly divided into 3 groups(control group /Control,Mulberry leaf group / MF and fermented Mulberry leaf group / FMF).),4 replicates per group(6 pigs/pen).The control group was fed a normal commodity finishing pig meals(basic meals),and the mulberry leaf group and the fermented Mulberry leaf group meals were supplemented with 5%(w/w)Mulberry leaves or fermented mulberry leaves in the basal meals.Slaughtered after 45 days of feeding.The results are as following:1.Fermentation could reduce the crude fiber content in mulberry leaves and increase the content of crude fat,crude protein and polyphenols.2.Mulberry leaves or fermented Mulberry leaves to the meals significantly increased the ratio of Gain to Feed(P < 0.05),reduced the thickness of the back of the living body and the thickness of the back of the carcass after slaughter(P < 0.05);There were no significant effects on carcass traits such as length,body width and eye muscle area(P > 0.05).3.TG(Triglyceride)and total cholesterol in the serum of mulberry or fermented Mulberry leaves were significantly reduced(P < 0.05);HDL(high density cholesterol)were significantly increased and LDL(low density cholesterol)were significantly decreased(P <0.05),HDL-c/LDL-c values were significantly increased(P < 0.01);FC(Free cholesterol)was significantly reduced only after the supplymnetary of Mulberry leaves(P <0.05);FFA(Free fatty acid),APO-A(Apolipoprotein A),APO-B(Apolipoprotein B)and Glucose showed no significant change(P > 0.05).The content of SOD(superoxidedismutase)in the serum of Mulberry leaves and fermented Mulberry leaves decreased significantly(P < 0.05),while the T-AOC(total anti-oxidative capacity)increased significantly in the Mulberry group(P < 0.05);there was no significant difference in MDA(malondialdehyde)and LPO(lipid peroxide)(P > 0.05).Mulberry leaves or fermented mulberry leaves significantly increased serum leptin(P <0.05);Adiponectin was significantly elevated only in the Mulberry group(P < 0.05);There was no significant change with circulating insulin and glucocorticoid(P > 0.05).4.After adding mulberry leaves or fermented Mulberry leaves,the expression of HSL(hormone sensitive lipase)protein in subcutaneous fat was significantly increased(P < 0.05),while ATGL(adipose triglyceride lipase)presented no significant change(P > 0.05).Among the lipogenic proteins,FAS(fatty acid synthase)significantly decreased after adding mulberry leaves(P < 0.05),but there was no significant change in FMF group(P > 0.05);C/EBP?(CCAAT/enhancer binding protein alpha),C/EBP?(CCAAT/enhancer binding protein),SREBP1(sterol regulatory element binding protein 1)and PPAR?(peroxisome proliferator activated receptor ?)were not significantly altered in the all groups(P > 0.05);Leptin-R(leptin receptor)was significantly increased(P < 0.05)after adding Mulberry leaves and fermented mulberry leaves,and the p-STAT3(phosphorylated STAT3)was also significantly increased in both treatment groups(P < 0.05),indicating that Leptin-mediated lipolysis was significantly enhanced.meanwhile,a significantly elevated Triglyceride was found in the liver and muscles of both treatments(P < 0.05).5.After increase mulberry leaves or fermented Mulberry leaves,but there was no significant change in pH,drip loss and flesh color(P > 0.05),except that water loss was significantly increased in the fermented Mulberry leaves group(P < 0.05);serine,valley,proline,phenylalanine and histidine were significantly decreased in the fermented mulberry group(P < 0.05),and other amino acids were not changed(P > 0.05);there was no significant changes of fatty acid composition and muscle antioxidant capacity.(P > 0.05).In summary,the addition of Mulberry leaves or fermented Mulberry leaves in the meals can significantly increase the ratio of Gain to Feed,reduce backfat thickness in finishing pigs,and increase the intramuscular fat contentwithout affacting pork quality.