| In modern intensive scale farming,laying hens face problems such as oxidative ageing of the organism,chronic inflammation and imbalance of the intestinal flora in the later stages of egg production,leading to a decrease in production performance and egg quality.In recent years,the use of herbs and their extracts as green feed additives in egg production has become a popular research topic and has achieved good results in improving the health of laying hens and increasing production performance.Dendrobium nobile Lindl is widely used in the pharmaceutical industry for its antioxidant,immunity enhancing and intestinal flora regulating effects,but less research has been conducted on Dendrobium nobile Lindl in livestock and poultry production.In this experiment,the effects of Dendrobium nobile Lindl on the egg production performance,serum biochemical indexes,egg quality and cecum flora of 55-week-old Chishui black-bone chickens were investigated.A total of 360 hens of similar body weight,free from diseases and normal egg production were randomly selected and divided into 4groups of 6 replicates each,with 15 hens in each replicate.The control group was fed the basal diet,while groups Ⅰ,Ⅱ and Ⅲ were the experimental groups.700 mg/kg,1 400mg/kg and 2 100 mg/kg of Dendrobium nobile Lindl were added to the basal diet for 90 days.The main results of the study were as follows:(1)Production performance: Feed intake,egg production,egg weight and stocking capacity were recorded daily during the trial period,and production performance indicators such as average daily feed intake,egg production rate,feed-to-egg ratio and average egg weight were calculated and analysed at the end of the trial.The results showed that the egg production rate increased by 4.59 %,1.20 % and 6.07 % with the addition of 700 mg/kg,1 400 mg/kg and 2 100 mg/kg Dendrobium nobile Lindl in the diet respectively compared to the control group.The egg production rate increased significantly(P < 0.05)with the addition of 2 100 mg/kg of Dendrobium nobile Lindl.The addition of 700 mg/kg,1 400 mg/kg and 2 100 mg/kg of Dendrobium nobile Lindl increased the average daily feed intake and decreased the average egg weight,but the difference did not reach a significant level(P > 0.05).(2)Serum biochemical indexes: Two chickens were randomly selected from each replicate,blood was collected,serum was separated,and serum biochemical parameters were tested and analysed according to the kit instructions.The results showed that the addition of 700 mg/kg Dendrobium nobile Lindl to the diet significantly increased the serum levels of total antioxidant capacity(T-AOC)and albumin(ALB)(P<0.05);the addition of 1400 mg/kg Dendrobium nobile Lindl significantly increased the serum levels of immunoglobulin A(Ig A)(P<0.05).The addition of 1 400 mg/kg and 2 100 mg/kg of Dendrobium nobile Lindl significantly reduced the serum levels of interferon-γ(IFN-γ)in the diet(P < 0.05).(3)Egg quality: At the end of the feeding trial,two eggs were collected randomly from each replicate and 12 eggs from each group were measured and analysed for egg quality.The results showed that the addition of 700 mg/kg Dendrobium nobile Lindl to the basal diet significantly increased the egg Haptogram and protein height(P < 0.05);the addition of 1400 mg/kg of Dendrobium nobile Lindl significantly increased the egg shell thickness(P < 0.05).No significant differences in egg weight,yolk weight,yolk colour and egg shape index between the four groups(P < 0.05).The addition of 700 mg/kg Dendrobium nobile Lindl to the diet significantly increased the levels of palmitic acid(C16:0),behenic acid(C22:0)and eicosadienoic acid(C20:2)in eggs(P < 0.05).The addition of 1400 mg/kg Dendrobium nobile Lindl to the diet increased the levels of oleic acid(C18:ln9c)and docosahexaenoic acid(C22:6n3)in eggs(P < 0.05).The addition of2100 mg/kg Dendrobium nobile Lindl to the diet significantly increased the levels of palmitic acid(C16:0),oleic acid(C18:ln9c),behenic acid(C22:0),docosahexaenoic acid(C22:6n3)and monounsaturated fatty acids(MUFA)in eggs(P < 0.05).Saturated fatty acids(SFA)were significantly higher and polyunsaturated fatty acids(PUFA)were significantly lower in all test groups(P < 0.05).The addition of 700 mg/kg of Dendrobium nobile Lindl can significantly increase the content of serine and glutamic acid in eggs(P < 0.05).The addition of 1 400mg/kg of Dendrobium nobile Lindl can significantly increase the content of serine,glutamic acid,glycine,alanine and phenylalanine in eggs(P < 0.05);the addition of 2100 mg/kg of Dendrobium nobile Lindl can significantly increase the content of aspartic acid,serine,glutamic acid,glycine,alanine,leucine,phenylalanine and lysine in eggs(P < 0.05).(4)Cecum microbiology: Based on preliminary production data,we collected cecum contents from the control and test group III,and determined and analysed the composition of the gut microbiology by high-throughput sequencing.The results showed that: The addition of 2100 mg/kg of Dendrobium nobile Lindl to the diet increased the abundance of Bacteroidot and Actinoba-cteriota species and decreased the abundance of Firmicutes,Desulfovibriota and Fusobacteria in the cecum.The abundance of Desulfovibriota,Synergistota and WPS-2 was significantly higher in the control group than in the test group,the proportion of Spirochaetota in the test group was significantly higher than in the control group at the phylum level(P < 0.05).The abundance of Lachnospiraceae,Veillonellaceae,Norank＿o＿Oscillospirales and Oxalobacteraceae in the control group was significantly higher than that in test group III.The abundance of Christensenellacea,Peptostreptococcaceae,norank＿o＿Clostridia vadin BB60＿group,Enterococcaceae,UCG-010,norank＿o＿WCHB1-41,and norank＿o＿Rhodospirillales in the control cecum were significantly less abundant than the control group(P < 0.05).In summary,the addition of Dendrobium chinense to the diets of Chishui woebone chickens has a positive effect on improving egg production,egg quality,immune performance,antioxidant properties and improving the structure of intestinal microorganisms. |
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