| On the basis of testing the in vitro antibacterial activity of barley worm larva powder extract,the effects of adding barley worm larva powder to the diet on the growth performance,luminal microbiome and metabolic group of yellow feathered broilers were studied.This study is divided into two parts: bacteriostasis in vitro and feeding experiment.The bacteriostatic effect of powder lipids extract from barley worm larvae on four kinds of bacteria was tested by bacteriostatic test.In the feeding experiment,475 1-day-old yellowfeathered broilers were randomly divided into 5 groups: control group(basic diet),antibiotic group(basic diet + 300 g gram t 15% chlortetracycline and 40 g gram t 50% virginiamycin),1% insect powder group(basic diet + 1% insect powder),2% insect powder group(basic diet+ 2% insect powder),3% insect powder group(basic diet + 3% insect powder).The dietary nutrition level of each group was the same.The experimental period was 63 days.From 1 to21 days old,there was no repetition in the brooding stage,and at the age of 22 days,each group was divided into 6 replications,with 12 chickens in each group.The body weight and feed consumption of chickens were counted at the age of 21,42 and 63 days,respectively.One chicken was selected for each repeat,and the contents of each intestinal segment,ileum and cecum were taken to determine the intestinal structure,intestinal flora structure and metabolism.The results are as follows:(1)Bacteriostasis in vitro: the diameter of bacteriostatic zone of lipid extract of barley worm against Escherichia coli,Escherichia coli,Salmonella and Staphylococcus aureus was31.54 ±0.32 mm,25.38 ±0.57 mm,33.92 ±0.73 mm and 22.17 ±0.51 mm,respectively.(2)growth performance: at the age of 22-42 days,compared with the control group,the average daily gain((ADG))of antibiotic group and each worm powder group increased significantly(P < 0.05).The body weight(BW)of antibiotic group,1% worm powder group and 3% worm powder group increased significantly(P < 0.05),and the feed gain ratio(F / G)decreased significantly(P < 0.05).Compared with the antibiotic group,the average daily gain((ADG))of 1% and 3% insect powder groups increased significantly(P < 0.05),and the feed weight ratio of each insect powder group increased significantly(P < 0.05).At the age of 43-63 days,compared with the control group,there was a significant difference in the final weight(BW)between the antibiotic group and the 1% insect powder group(P < 0.05).(3)Digestive tract length: at 21 days old,compared with the control group,the length of cecum in 1% insect powder group and 3% insect powder group increased significantly(P< 0.05);at 42 days old,compared with the control group and antibiotic group,the duodenum length in 3% insect powder group increased significantly(P < 0.05).(4)luminal microorganism group: the ileal contents of 63-day-old control group,antibiotic group and 1% insect powder group were sequenced and analyzed by 16 sr DNA.Compared with the control group,the ileal bacterial community richness in the antibiotic group and 1% insect powder group increased significantly(P < 0.05),and the cecal bacterial community richness decreased,among which the 1% insect powder group had a very significant difference(P < 0.01).Shannon index showed that compared with the control group,the ileal bacterial community diversity of the antibiotic group decreased,the ileal bacterial community diversity of the barley worm group increased,and the cecal diversity of the antibiotic group and 1% insecticidal powder group decreased,but the difference was not significant(P > 0.05).In the composition of the microbial community at the gate level,compared with the control group,the structure of the dominant microflora in the ileum and cecum of the antibiotic group and 1% insect powder group changed;in the composition of the genus-level microbial community,there was no change in the dominant microflora structure of ileum in the control group,antibiotic group and 1% insect powder group,but changed in the cecum dominant microflora structure in the control group,antibiotic group and 1% insect powder group.(5)Metabolic group: there was no difference in short-chain fatty acids in ileum and cecum of yellow-feathered broilers in all treatment groups(P > 0.05).Compared with control group and antibiotic group,the content of cholic acid in ileum in 1% insect powder group increased significantly(P < 0.05).Compared with the control group,23 metabolites in the ileal contents of the antibiotic group were up-regulated,of which 17 were amino acids(15 amino acids P < 0.01,2 amino acids P < 0.05),and 19 metabolites were up-regulated in 1% insect powder group.Among them,there were 16 kinds of amino acids(3 kinds of amino acids P < 0.01,9 kinds of amino acids P < 0.05).Compared with the antibiotic group,14 kinds of differential metabolites in the ileum contents of 1% insect powder group were down-regulated.Except serine(P < 0.05),there was no significant difference among the other 6 amino acids(P > 0.05).To sum up,the powder lipid extract of barley worm larvae had obvious inhibitory effect on four kinds of common pathogenic bacteria;under the condition of no resistance,adding appropriate amount of barley worm larva powder could improve the production performance and intestinal structure of yellow-feathered broilers.Increase the richness and diversity of ileal bacterial community,change the relative proportion of bacterial community at phyla and genus level,and increase the content of cholic acid in ileum.The addition of 1% insect powder and antibiotics(chlortetracycline and virginiamycin)had significant effects on the microbial metabolism in the ileal lumen of yellow-feathered broilers,which could significantly or very significantly increase the content of free amino acids in the ileum. |
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