| The aim of this experiment is to investigate the effect of yam polysaccharides on muscle development in broilers,and to explore the effect of yam polysaccharides on improving muscle development.A total of360(1-day-old,sex balance)healthy growing hybrid broiler 817 with similar body weight(39.54 ± 0.51 g)hybrid broiler 817 were randomly divided into 4 groups and fed with different amounts of Chinese yam polysaccharides as a basal diet: control(0.00 g/kg),CYP I(0.25 g/kg),CYP II(0.50 g/kg),and CYP III(1.00 g/kg)groups.Each group contains 3 replicates with 30 broilers in each replicate,and the feeding trial lasted 48 d.Cage rearing was adopted to control temperature and light,and all broilers had free access to food and water during the experiment.This study indicated:1.Effect of Chinese yam Polysaccharides on the level of transcriptome in thigh muscle of 48 day old broilers:Using RNA seq technology,the thigh muscle tissues of the gal-tja(control group)and gal-tjb(CYP II group)groups were analyzed.After screening for differentially expressed genes,4522 significantly differentially expressed genes were identified,including 2464 upregulated genes and 2058 downregulated genes.Through GO enrichment analysis and KEGG enrichment analysis of differentially expressed genes(MYOD1,MYOG,etc.),it was found that yam polysaccharides can activate the MAPK signaling pathway,Apelin signaling pathway,and Wnt signaling pathway.By upregulating the expression of muscle development related genes,it promotes the growth,development,and maturation of muscle cells.2.Verification of some differential genes in transcriptome and the effect of Chinese yam polysaccharides on the expression of key genes in muscle development:At 28 days,the MYOD1 gene expression in breast muscle tissues of experimental group was higher than that in control group,CYP I group and CYP III group(P<0.05),the MRF4 gene expression in CYP I and CYP III groups was significantly higher than that in control group(P<0.05),the MHC and IGF-I gene expression in experimental group were higher than those in control group(P<0.05),the IGF-IR gene expression of CYP I and CYP II groups was higher than that of control group(P<0.05),the MSTN gene expression in CYP II and CYP III groups was lower than that in the control group(P<0.05).In thigh muscle tissues,the MYOG,MHC,IGF-I and IGF-IR gene expression in CYP II group were significantly higher than those in control group,CYP I group and CYP III group(P<0.05),the MSTN gene expression in experimental group was lower than that in control group(P<0.05).At 48 days,in breast muscle tissues,the MYOD1 and MYOG gene expression in CYP II and CYP III groups were higher than those in control group(P<0.05),and the MRF4 gene expression in CYP II group was significantly higher than that in control group,CYP I and CYP III groups(P<0.05),the MHC gene expression in experimental group was significantly higher than that in control group(P<0.05),the IGF-I and IGF-IR gene expression in CYP I and CYP III groups were higher than those in control group.In thigh muscle tissues,the IGF-I and IGF-IR gene expression in experimental group were higher than those in control group(P<0.05).Meanwhile,the MSTN gene in experimental group was lower than that in control group(P<0.05).The results showed that adding Chinese yam Polysaccharides to the diet of broilers had a significant impact on key genes for muscle development in breast and thigh muscle tissues.3.Effects of Chinese yam Polysaccharides on muscle development of broilers:In breast muscle tissues,the MRF4 gene expression in CYP I group was significantly positively correlated with breast muscle rate(MRF4/Breast muscle percentage,r=0.851,p=0.032),while the gene expressions of MYOD1,MYOG,MHC,IGF-I,IGF-IR and MSTN in all groups were not significantly correlated with breast muscle rate and thigh muscle rate(P>0.05).In thigh muscle tissue,the MYOD1,MYOG,MRF4,MHC,IGF-I,IGF-IR and MSTN gene expression in CYP II group were significantly positively correlated with thigh muscle rate(MYOD1/Thigh muscle percentage,r=0.819,p=0.046;MYOG/Thigh muscle percentage,r=0.912,p=0.011;MRF4/Thigh muscle percentage,r=0.889,p=0.018;MHC/Thigh muscle percentage,r=0.944,p=0.005;IGF-I/Thigh muscle percentage,r=0.891,p=0.017;IGF-IR/Thigh muscle percentage,r=0.939,p=0.005;MSTN/ Thigh muscle percentage,r=0.851,p=0.032),and the MYOG,MHC,IGF-I and IGF-IR gene expression in CYP III group were significantly negatively correlated with thigh muscle rate(MYOG/Thigh muscle percentage,r=-0.973,p= 0.001;MHC/Thigh muscle percentage,r=-0.888,p=0.018;IGF-I/Thigh muscle percentage,r=-0.854,p=0.030;IGF-IR/Thigh muscle percentage,r=-0.953,p=0.003).In summary,feeding broilers with different amounts of Chinese yam Polysaccharides can significantly increase the expression of key positive regulatory genes for muscle development in the breast and thigh muscles of broilers at different ages,while inhibiting the expression of negative regulatory genes,thereby affecting the growth and development of muscle tissue.Therefore,Chinese yam Polysaccharides can serve as potential feed additives to promote muscle tissue development in broilers. |
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