| The aim of this study was to investigate the effects of different levels of Artemisia argyi polysaccharide(AAP)in diets on growth performance and intestinal related indexes in broilers.A total of 288 healthy 1-day-old AA broilers with similar body weight were randomly divided into 6 diet treatment groups with 6 replicates per treatment group and 8 chickens per replicate(half male and half female).Diets of the six groups were prepared by adding 0,250,500,750,1000 mg/kg AAP and 50 mg/kg chlortetracycline to the basal diet.The test period was 42 days,divided into two periods,the earlier stage(d 1-21)and the later stage(d 22-42).The test results were as follows:1.In the earlier stage,compared with the control group,750 mg/kg AAP significantly reduced the average daily feed intake of broilers(P<0.05).In the later stage,1000 mg/kg AAP significantly increased the average daily gain(P<0.05).In addition,the AAP group and the antibiotic group significantly reduced the ratio of feed to weight(P<0.05).2.In the earlier stage,compared with the control group and the antibiotic group,the 1000 mg/kg AAP group significantly increased the apparent metabolic rate of DM,which increased by 17.15%and 17.28%,respectively(P<0.05).In the later stage,compared with the control group,750,1000 mg/kg AAP group and antibiotic group significantly increased the apparent metabolic rate of CP,which increased by 13.11%,10.99%,10.07%,respectively(P＜0.05).The apparent metabolic rate of DM(P=0.089),EE(P=0.056)and Ca(P=0.072)had an increasing trend.3.In the earlier stage,compared with the control group,the jejunal chymotrypsin activity of 1000 mg/kg AAP group increased by 37.57%(P<0.05),the jejunal trypsin activity of all the AAP groups and antibiotic group was significantly increased(P<0.05),and 1000 mg/kg AAP group had the best effect,but there was no significant difference in ileal amylase and lipase activity between groups(P>0.05).In the later stage,compared with the control group,the duodenal trypsin activity of 500,750,1000 mg/kg AAP groups and the antibiotic group was significantly increased by 47.57%,64.92%,63.50%and 69.52%,respectively(P<0.05).1000 mg/kg AAP group and antibiotic group increased trypsin activity in jejunum and ileum(P<0.05).The jejunal lipase activity of 750,1000 mg/kg AAP groups and antibiotic group increased by 27.89%,33.15%and 41.43%,respectively.The jejunum amylase activity of 1000 mg/kg AAP group increased by 69.49%.4.In the earlier stage,compared with the control group and the antibiotic group,750 mg/kg AAP group significantly increased the villus height of duodenum by 14.45%and 22.55%,respectively(P<0.05).In the later stage,compared with the control group and the antibiotic group,1000 mg/kg AAP group significantly increased ileum villus height by 20.72%and 13.19%,respectively(P<0.05).Compared with the control group,all the AAP groups and antibiotic group significantly reduced the depth of crypts in the duodenum and jejunum(P<0.05),and AAP groups had better effect than the antibiotic group.The 250,500,1000 mg/kg AAP groups significantly increased the ratio of villus height to crypt depth in ileum by 19.57%,16.34%and 24.06%,respectively(P<0.05).5.In the earlier stage,compared with the control group,all the AAP groups and antibiotic group decreased the number of E.coli in caecum(P＜0.05),the number of Lactobacillus had an increasing trend(P=0.100).In the later stage,compared with the control group,750 and 1000 mg/kg AAP groups and the antibiotic group significantly inhibited the proliferation of E.coli(P<0.01),and the number of Lactobacillus in each AAP groups increased significantly(P<0.05).The number of bifidobacteria tended to increase(P=0.093),but the number of total aerobic bacteria tended to decrease(P=0.083).6.The results of fecal gas production test in vitro showed that,in the earlier stage,all the AAP groups and antibiotic group significantly decreased ammonia release by 44.59%,55.47%,48.77%,50.22%and 55.89%respectively,at 48 h compared with the control group(P<0.05).In the later stage,compared with the control group,the AAP groups and the antibiotic group significantly inhibited the emission of ammonia in the feces at 24 h(P<0.05),and the AAP groups had better effect.At 72h,except for the 500 mg/kg AAP group,the other groups significantly reduced the emission of ammonia,and the 1000 mg/kg AAP group had the best effect.In general,AAP showed a significant inhibitory effect on ammonia release from the fermented manure.The above results showed that the addition of AAP in the diet enhanced the activity of intestinal digestive enzymes,improved the intestinal mucosal morphology,regulated the intestinal micro-ecological system,thereby increased the apparent metabolic rate of nutrients and promoted the growth performance of AA broilers,meanwhile reduced the ammonia release in the feces. |
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