| . The tilapia intestine was used in this research.The bodies were assigned to 4 treament groups randomly that each group had 20 tilapias whose initial length were 10cm and average weight 75.0±5.0g.The groups were fed as follows:1.The control diet, 2.The control diet supplemented with 0.05% APS,3.The control diet added with 0.1% APS,4.The control diet added with 0.15% APS.After one month feeding,we studied the influence of APS on the structure of intestinal mucous, the quantitative changes of immunity cells associated with intestinal tracts, the activities of lysome in intestinal tracts and the changes of intestinal microflora of tilapia.The study was to investigate the effects of APS on the intestinal mucous immunity.Three parts were contained in this study, as follow:1.Effects of APS on the structure of intestinal mucous and the quantitative changes of immunity cells associated with intestinal tracts.We observed the morphic changes of intestinal villus of the tilapia by HE staining.The results showed that the length of intestinal villus in the group2 were much longer than the control group in fore-gut and the intestinal villus in group 3 increased 29.61% than the control group in fore-gut,which were extremely different from the control group(P<0.01).In mid-gut and hind-gut, the length of intestinal villus in group 3 were much longer than the control group.The changes of villus width were not obvious in the experiment.The submucous muscle layer depths of group 3 has increased 18.83% contrast to the group1 in fore-gut, In hind-gut, the depth of submucous muscle layer had increased according to various degrees of APS.2.The quantitative change of goblet cell were observed by AB-PAS staining in fore-gut,mid-gut and hind-gut.The aim is to find out the quantitative changes of goblet cell at different levels of APS.The results indicated that the quantity of the goblet cell varied significant between group2 and control group (p<0.01) in fore-gut and mid-gut and the result was the same as group3.The quantitative changes of mast cell were observed by Alcian Blue and Safranine staining in fore-gut,mid-gut and hind-gut.We aimed to find out the quantitative changes of mast cell at different levels of APS.The results showed that the difference of mast cell's quantity was not significant in fore-gut,mid-gut and hind-gut among all the groups(p>0.05).However, the quanities of mast cell had the trend of increasing in intetinal tracts of tilapia.The quantitative changes of intestinal intraepithelial lymphocytes(iIEL) were observed by HE staining in the intestinal tract in tilapia.The results showed that in fore-gut and mid-gut,the difference of quantities of iIEL was significant contrast to the control group.2.To study the influence of APS on the lysome of intestinal tracts in tilapia.After one month feeding, 4 tilapias were dissected from each groups, divided into fore-gut,mid-gut and hind-gut, then compared the lysome viabilities of different intestinal tracts by lysome test kits.The results showed that the group which added 0.1% APS had significantly increased lysome viability in fore-gut and mid-gut of tilapia.3. Effect of APS on intestinal microflora of tilapia was carried out.The bacterial community structure in the intestine of tilapia was investigated by using a culture- independent method of 16S rDNA PCR-DGGE fingerprinting. DNA of bacteria in intestinal tract of tilapia was isolated,then using DGGE to analyze the dominant bacteria in intestinal tract.The result showed that the samples which added 0.1% and 0.15% APS would increase the quantitatives of beneficial bacterias and decrease the number of harmful bacterias. It demonstrated that APS could improve intestinal flora in tilapia.Conclusion: Adding APS in basic diets could improve the tilapia intestinal mucosal morphology, increase the intestinal mucosa-associated immune cells quantity, enhance intestinal lysozyme activity and the intestinal flora, thereby the intestinal mucosal immune fuction was enhanced. |
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