| Lactobacillus has extensive probiotics effects as probiotic bacteria,which is distributied widely in the gastrointestinal tract of livestock and poultry,such as maintaining microecological balance of the gastrointestinal tract,enhancing the body resistance to infection,inhibiting proliferation of pathogenic bacteria,promoting the growth of beneficial bacteria.The abusing of antibiotics in modern livestock production has led to the killing of a lot of beneficial bacteria at the same time of killing pathogen bacteria,which is not beneficial to the balance of animal gut microbes,and has the shortcomings such as medicine residues in animal products and reducing of drug resistance.Lactic acid bacteria occupies the dominant position with safe,ecological characters among the studies of antibiotics substitutes.A lot of studies of Lactobacilli were carried on,such as research of content of intestinal bacteria;determine the effect on the body by feeding probiotics preparation;improve daily weight gain of broiler by feeding additive lactobacillus preparation and so on.Various studies have shown that the periods of the role of Lactobacilli is associated with the day-age of chickens,the content of bacteria is different by day-age,different bacteria occupy different segments of the digestive tract,Lactobacillus play a different role in different conditions.Ideal lactic acid bacteria strains is isolated from the same spieces of animals,to enhance the specific probiotic effect.There was no report of systemic research for different age & different intestinal segments of lactobacillus sp.among poultry.So the purpose of this study is to understand the modify trend of lactobacillus sp.isolated from poultry intestinal in different day-age & different intestinal segments and the distribution of lactobacillus strain,Rose 308 broilers were emploied as research subjects in our studies,luminal contents were collected under sterile environment from 1,5,10,20,30day-age chicken from the duodenum,jejunum,ileum,cecum and rectum,after double dilution,plat spreading,colony counting,morphological observation,smear slide review by microscopy,polymerase chain reaction(PCR)using lactobacillus universal primers,16s-amplified rDNA restriction analysistechnology(ARDRA)combined with DNA sequencing,5 lactobacillus strains were screened and identificatied eventually,which were Lactobacillus helveticus isolates strainⅠ,L.helveticus isolates strainⅡ,L.johnsonii,L.reuteri,L.crispatus respectively.Most of the 5 lactobacillus strains were distributed in the cecum,L.johnsonii,L.reuteri,L.helveticus isolates strainⅡ,L.crispatus were distributed in duodenum,jejunum,ileum,cecum and rectum;L.helveticus isolates strainⅠ were mainly distributed in duodenum,jejunum and caecum,which were not found in ileum and rectum.Variation of lactobacillus isolated with the change of broiler ages,L.johnsonii,L.reuteri had shown gradually increasing trends except on age 5,L.helveticus isolates strain Ⅱ or L.crispatus were also presented a tendency of increasing with thegrowing of ages;L.helveticus isolates strainⅠ was relatively uniform distribution,amounts variation was not obvious.Statistics results showed that L.johnsonii and L.reuteri accounting for 81.82%,L.helveticus isolates strain Ⅱ and L.crispatus accounting for 9.09%,L.helveticus isolates strainⅠ accounting for 6.67%,hence it was not difficult to conclude that L.johnsonii,L.reuteri were main dominant bacteria.Different distributions of different intestinal segments of lactobacilli species had big relationship with their functions,but in areas of husbandry application practice,screening of appropriate strain can lay the foundation for the development of related products and clinical trials,ensure significant effect of probiotics preparation,as well as provide theoretical and technical support for the development and application of Lactic acid bacteria microecological preparation. |
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