| In this study,antibiotics,yeast culture,Chinese herbal medicine additive,along with the combination of yeast culture and Chinese herbal medicine were added to the diet of laying hens to investigate the effects on their production performance,egg quality,nutrient metabolism,antioxidant function and immune function.Meanwhile,the main purpose of this study was to evaluate whether the additives above can be a replacement of antibiotics.A total of 1200 27-week-old Roman laying hens were divided into 5 treatment groups(6 replicates per group with 40 hens per replicate),treatment 1 was control group and fed with basal diet(CON group),treatment 2 fed with basal diet supplemented with 50 mg/kg antibiotic bacitracin zinc(ABX group),treatment 3 fed with basal diet supplemented with 3% yeast culture(YC group),treatment 4 fed with basal diet supplemented with 0.04% Chinese herbal medicine additive(CHM group),treatment 5 fed with basal diet supplemented with 3% yeast culture and 0.04%Chinese herbal medicine additive(Y+C group).The pre-feeding period was 1 week,the trial period was 8 weeks.During the trial period,the performance indexes of egg production were determined,and blood and tissue samples were collected,after measuring the immunity,antioxidation and intestinal microorganism indexes of laying hens.The results showed that:(1)Compared with the CON group and ABX group,the laying rate was significantly increased in CHM group and Y+C group(P < 0.05),but there were no significant differences in egg weight,feed intake and feed-egg ratio(P > 0.05).The egg white height and Haugh unit were significantly increased in YC group,CHM group and Y+C group compared to the CON group(P < 0.05),compared with the CON group and ABX group,there was no significant difference in eggshell strength and eggshell thickness among all groups(P > 0.05).(2)Compared with the CON group,the spleen and pancreas index markedly improved in CHM and Y+C group(P < 0.05).Compared with the ABX group,the spleen index was significantly increased in CHM group,and spleen index and pancreas index in YC group were not significantly different from that in CON group and ABX group(P > 0 05).There was no significant difference in liver index among all groups(P > 0.05).(3)Compared with the CON group and ABX group,the content of serum IL-2 in YC group,CHM group and Y+C group increased significantly(P < 0.05),and the TNF-α decreased not significantly(P>0.05).Compared with the CON group,the content of IL-6,IL-8 in serum decreased significantly and IFN-γin serum increased significantly in YC group,CHM group and Y+C group(P<0.05).(4)Compared with the CON group and ABX group,the contents of serum immunoglobulin IgA,IgM and IgG in YC group,CHM group and Y+C group were significantly increased(P<0.05).(5)Compared with the CON group,the content of liver T-AOC in YC group,CHM group and Y+C group was significantly increased(P<0.05),the content of liver SOD in CHM group was significantly increased(P<0.05),the content of SOD in liver had an increasing trend in Y+C group(P=0.079),the content of MDA in liver was significantly decreased in YC group,CHM group and Y+C group(P<0.05).Compared with ABX group,the SOD in CHM group was significantly higher than that in ABX group(P<0.05),the SOD in YC group,and Y+C group were improved compared with ABX group,but there was no significant difference(P>0.05).Compared with the CON group,serum GSH-Px and T-AOC were significantly increased in CHM group and Y+C group(P<0.05),serum SOD in YC group,CHM group and Y+C group was significantly increased and MDA was significantly decreased(P<0.05).Compared with ABX group,SOD and T-AOC were significantly increased in CHM group and Y+C group(P<0.05).(6)Compared with the CON group,the villus height of jejunum was significantly increased in YC group and Y+C group(P<0.05),compared with the ABX group,the villus height was significantly reduced in CHM group(P<0.05);there were no significant differences in crypt depth and V/C ratio among all groups(P>0.05),the number of lymphocytes in YC group was significantly lower than that in CON group(P<0.05),and there was no significant difference among other groups(P>0.05),the number of goblet cells in ileum in CHM group and Y+C group was significantly higher than that in CON group ABX group(P<0.05).Compared with the CON group,the number of goblet cells in YC group showed increasing trend(P=0.051).Compared with the CON group,the crypt depth in YC group,CHM group and Y+C group decreased significantly(P<0.05),the V/C ratio were increased(P=0.077),and the number of lymphocytes in YC group,CHM group and Y+C group decreased significantly compared with the CON group(P<0.05).The number of goblet cells in ileum in YC group and Y+C group was significantly lower than that in the CON group(P<0.05).(7)Compared with the CON group,the number of OTU in cecum of CHM group,Y+C group and YC group increased,while OTU in ABX group decreased.At the phylum level,the abundance of Firmicutes was decreased and Bacteroides was increased in CHM group(P > 0.05).At the family level,the abundance of Bacteroidaceae decreased(P > 0.05),the abundance of Lactobacillaceae increased(P > 0.05)and the abundance of Prevotellaceae increased(P < 0.05)in YC group,CHM group and Y+C group,the abundance of Rikenellaceae in ABX group and CHM group increased(P > 0.05).At the genus level,compared with the CON group,the abundance of Bacteroides decreased and the abundance of Lactobacillus increased in YC group,CHM group and Y+C group(P > 0.05).(8)Compared with the CON group,antioxidation and immune function were probably regulated by amino acid metabolism(glutamate metabolism,etc.),glucose and lipid metabolism(taurine metabolism,etc.),quinone metabolism(ubiquinone biosynthesis,etc.).(9)Compared with the CON group,the relative expression of IL-6 gene in CHM group decreased(P = 0.094),the relative expression of TNF-α gene in spleen decreased significantly in YC group and CHM group(P < 0.05),and there was no significant difference in the relative expression of IFN-γ gene in each group(P >0.05).Compared with the CON group,the relative expression of NF-κB gene in YC group and CHM group was no significant difference(P > 0.05).Compared with the CON group and ABX group,the relative expression of Nrf2 gene was significantly increased in YC group and Y+C group(P < 0.05).In summary,the results above showed that adding Chinese herbal medicine additive,the combination of yeast culture and Chinese herbal medicine could improve the production performance and egg quality of laying hens,along with the enhancement of their immune function,antioxidant capacity,intestinal morphology,diversity and relative abundance of cecal microorganisms,and also regulating nutrient metabolism,which superior to the benefits of using antibiotics.It is expected to be a security and efficient substitute of antibiotics in animal production. |
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