| Probiotics are a type of microorganism that is beneficial to the host.Previous studies have found that probiotics can improve the intestinal microecological balance and play a beneficial role,but the study of the regulation and mechanism of probiotics on the intestinal function of broilers is still insufficient.Therefore,this study investigated the effects of early colonization of probiotics on growth performance,intestinal villus morphology,intestinal pH,intestinal digestive enzymes,and small intestinal nutrient transport carriers,and explored the possibility of artificially added probiotics to alter gastrointestinal function in broilers.Trying to analyze the intestinal body material and transporter gene expression of chicks to study the molecular mechanism of intestinal microbes on the intestinal function of the host,to provide a theoretical basis for the application of probiotics in broilers.One hundred 400 white broilers at the age of 1 day were divided into 5 groups with 8replicates in each group with 10 replicates each.Among them,group A was used as a control group(no antibiotics),and group B was an antibiotic group(0.5g/kg was added),group C is Bacillus subtilis group(without anti-nurs diet added 0.5g/kg Bacillus subtilis preparation),group D is lactic acid bacteria group(no antibiotics added 0.5g/kg lactic acid bacteria preparation),E group is subtilis Bacillus + lactic acid bacteria group(Bacillus subtilis: lactic acid bacteria = 1:1).The main findings are as follows:1)Growth performance of broilers: Compared with the control group,the effects of addition of omemycin,Bacillus subtilis,lactic acid bacteria,and two mixed bacteria on the average feed intake of broilers from 1 to 21 days were not significant(P>0.05).The average daily feed intake of broilers from 22 to 42 days and 1 to 42 days was significantly increased(P<0.05),and the average daily gain of broilers from 1 to 21 days,22 to 42 days,and 1 to 42 days was significantly increased(P<0.05).The effect of feed weight ratio of ~21d was not significant(P>0.05),but the feed/weight ratio of 22 ~ 42 d and 1 ~ 42 d was significantly reduced(P<0.05).2)Intestinal pH of broilers: Compared with the control group,the effect of addition of omemycin,Bacillus subtilis,lactic acid bacteria,and two mixed bacteria on the intestinal pH of 21 st and 42 d broilers was not significant(P>0.05).3)The morphological structure of broilers' small intestine: Compared with the control group,the addition of dexamethasone,Bacillus subtilis,lactic acid bacteria group,and two mixed bacteria can significantly increase duodenal villus height and crypt depth of broilers for21 days.(P<0.05),but the effect on the jejunum and ileum morphology of broiler chickens was not significant(P>0.05).However,compared with the control group,adding bacillus,Bacillus subtilis,lactic acid bacteria group,two mixed bacteria to 42 d The morphological effects of broiler duodenum,jejunum,and ileum were not significant(P>0.05).4)Serum biochemistry: Compared with the control group,the addition of dexamethasone to the diet had no significant effect on the total protein,albumin,and IgM levels in the broilers of 21d(P>0.05),and significantly decreased the content of IgA and IgG(P<0.05).There was no significant effect on total protein,albumin,IgA,IgM and IgG in serum of 42 d broilers(P>0.05).Compared with the control group,the addition of Bacillus subtilis,lactic acid bacteria group,and the two mixed bacteria had no significant effect on the total protein,albumin,IgA,IgM content in the serum of 21 d broilers(P>0.05),and significantly increased the serum of 21 d broilers.The content of IgG(P<0.05)had no significant effect on total protein,albumin,IgM and IgG in serum of 42 d broilers(P>0.05),and it could significantly increase IgA content in serum of 42 d broilers(P<0.05).5)Digestive enzymes in broilers: Compared with the control group,the addition of omepromycin to the diet had no significant effect on digestive enzymes in the contents of small intestine of 21 d broilers(P>0.05);The effect of lipase and amylase activity was not significant(P>0.05),but the activity of trypsin was significantly decreased(P<0.05).Addition of Bacillus subtilis,Lactobacillus,and two mixed bacteria had no significant effect on the activity of trypsin in the small intestine contents of broiler chickens 21 days and 42 days(P>0.05),and could significantly increase lipase and amylase activity(P<0.05),in which lactobacillus feeding had the greatest effect on amylase activity.6)Intestinal transporter gene expression in broiler chickens: Compared with the control group,the addition of omemycin,Bacillus subtilis,lactic acid bacteria,and two mixed bacteria in the diet significantly increased the expression of PepT1 and GLUT2 mRNA in the small intestine of broiler chickens 21 days and 42 days,and down-regulated apoB mRNA expression(P<0.05).In summary,the addition of Bacillus subtilis and lactic acid bacteria to feeds can promote the growth of broilers,and improve the serum biochemical indicators,intestinal morphology and intestinal digestive enzymes of broilers.The mRNA expression of PepT1 and GLUT2 in the small intestine of broilers was up-regulated,and the expression of apoB mRNA was down-regulated,suggesting that Bacillus subtilis and Lactobacillus may increase protein turnover,glucose uptake,decrease fat deposition,and promote the intestinal absorption function of broilers. |
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