Effects Of Two Polysaccharides On Its Intestinal Micr- Biota, Digestive Enzymes And Intestinal Morphology

Objective:Firstly,this experiment investigated the intestinal environment of Schizothorax prenanti Tchang in different ages and weights(the weights were among 100-300g,the big ones were 300±0.15g,the middle ones were 200±0.15g,the little ones were 100±0.15g),including the isolation and identification of Aeromonas hydrophila,actobacillus and Bacillus with its capacity of enzyme production, analysised the intestinal microbial communities by PCR-DGGE and intestinal ultrastructure. Secondly,chosen the little fish were fed either a control diet or diets supplemented with the OKGM levels of 0.8,1.6,3.2% or the RS levels of 3.2%,6.4% to investigate effects of the two prebiotics on the activity of intestinal digestive enzymes,intestinal ultrastructure, hindgut microbial communities and the amounts of Aeromonas hydrophila,Lactobacillus and Bacillus,.These studies encouraged conducting further research on the administration of OKGM,RS and other prebiotics in fish fry studies. The main conclusios were as follows:1-. The analysis of intestinal environment:three isolated strains were all pathogenic Aeromonas hydrophila and three isolated strains(YB-03,YB-08,YB-20) were all Bacillus,but YB-08 was Amyloliquefaciens Bacillus and YB-03,YB-20 were Subtilis Bacillus,.and all the Bacillus could produce protease and amylase which had stable cacipity and highly enzyme production,the six isolated Lactobacillus were Lactobacillus brevis(RS-01,RS-04),Lactobacillus coryniformis(RS-02,RS-06) and Lactobacillus curvatus(RS-03,RS-09);The results of PCR-DGGE showed that the different ages of fish had medium similarity,the middle and little fish had higher similarity,but the big fish had highest diversity;The results of intestinal ultrastructure showed that the villus height, inner circular muscularis thickness and outer longitudinal muscularis thickness were increased with ages,but the mucosa epithelial in foregut and midgut of little fish was higer than others.2-. The effects of two kinds of polysaccharides on intestinal based indices and digestive enzyme activities:There were no significant effection on the basic indicators of intestinal(p>0.05),the dietary OKGM and RS levels significantly increased in intestinal digestive enzyme activities for hindgut protease,midgut and hindgut amylase,midgut lipase respectively compared with control(p<0.05),especially the 3.2% level of OKGM had more effction on hindgut protease activity than other levels and 1.6% level of OKGM had more effction on midgut and hindgut amylase activity than other levels.However,the dietary OKGM and RS levels decreased the activities for hindgut lipase activiey(p<0.05).3、The effects of dietary OKGM and RS levels on intestinal ultrastructure: 1)Foregut:the dietary OKGM could significantly increase the height of villus, mucosal epithelium (p<0.05) and decreased the thickness of the inner muscular layer and outer longitudinal muscle layer,and L-OKGM group had more effection than other group;the dietary RS could decreased the height of villus,mucosal epithelium, and the thickness of inner muscular layer and outer longitudinal muscle layer, and the villus was damaged in H-RS group.2)Midgut:the dietary OKGM could increase the height of villus and decreased the height of villus, the height of mucosal epithelium was decreased in H-OKGM and M-OKGM groups,but increased in L-OKGM grop;the dietary RS could decreased the height of villus,mucosal epithelium and the thickness of inner muscular layerouter longitudinal muscle layer.3)Hindgut:the dietary OKGM could increase the height of villus and the thickness of inner muscular layer and outer longitudinal muscle layer,decrease the height of mucosal epithelium, but no significantly differences were observed among the grops; the dietary RS could decreased the height of villus,mucosal epithelium and the thickness of outer longitudinal muscle layer,increase the thickness of inner muscular layer.4、The effects of dietary OKGM and RS levels on intestinal microbial:No significantly changes in similarity were observed by the dietary RS,but the dietary OKGM affected the intestinal microbial ecologica parameters significantly,the L-OKGM group had lowese similarity(67.2).The dietary OKGM could increase the diversity of intestinal microbial,and the level of 1.6% of OKGM increased 10.20% compared with control group(p<0.05).But the RS decreased the diversity of intestinal microbial,and there were no significantly differences between the 3.2% and 6.4% levels of RS(p>0.05).5、The effects of dietary OKGM and RS levels on the amounts of Aeromonas hydrophila and Bacillus:the OKGM and RS dietary could decreased the amounts of Aeromonas hydrophila,and the dietary levels were higher,the amounts were decreased more. The amounts of Bacillus and Lactobacillus were increased by the dietary OKGM and RS,especially in the hindgut.