| SUMMARY In order to solve the problem of probiotics and phytase application,this research focused on phytase gene transformed in Lactobacillus.After the modified Lactobacillus was given to animals,it would survive in animal gut to have both functions of phytase and probiotics.The results are as follows:(1) Effect of the transformed Lactobacillus on pig production performance:Fifty-six healthy piglets(Duroc×Landrace×Pietrain) were divided into 7 groups(A,B,C,D,E,F,G) at random according to their weight and sex,8 pigs for each group.Group A,the control group;group B,lysozyme group(500mg/kg);group C,antibiotics group(500mg/kg);group D,20%dicalcium phosphate removed from the control droup + transformed Lactobacillus with phytase gene(500mg/kg);group E,20%dicalcium phosphate removed from the control droup + natural Lactobacillus(500mg/kg);group F,40%dicalcium phosphate removed from the control droup + transformed Lactobacillus with phytase gene(500mg/kg);group G,40% dicalcium phosphate removed from the control droup + commercial phytase(500mg/kg).The feeding experiment was 70 days.The results showed that average dialy gain(ADG) and the grian feed ratio(G/F) were not significant different among 7 groups(P>0.05),even though ADG and G/F in group D were 10.6%and 8.7%more than that in group A.The diarrhea rate in group D was 48.0%and 32.8%less than that in group A and B group(P<0.01,P<0.05), Group D had stronger ability to prevent E.coli and improve animal production when the pigs were chalanged with pathogenic E.coli(P<0.05),compared with the other groups.After 40% dicalcium phosphate was removed from the diet,the production performance was worse,but it was not significant(P＞0.05).(2) Effect of the transformed Lactobacillus with phytase gene on nutrient digestibilities of piglets:The result showed that protein digestibilities of the group added with transformed lactobacillus with phytase gene were 13.38%(P＞0.05 ),6.95%(P＞0.05 ),40.72%(P＜0.01 ) and 18.59%(P＜0.05 ) higher than that in the blank control,antibiotic,natural Lactobacillus and phytase groups,respectively.Calcium digestibilities in the group added with transformed Lactobacillus with phytase gene were 29.77%(P＜0.01 ),40.77%(P＜0.01 ),95.31%(P＜0.01 ) and 23.32%(P＜0.05 ) higher than that in the blank control,antibiotic,natural Lactobacillus and phytase groups,respectively.Phosphorus digestibilities in the group added with transformed Lactobacillus with phytase gene were 30.39%(P＜0.01 ),18.45%(P＜0.05 ), 64.90%(P＜0.01 ) and 22.24%(P＜0.05 ) higher than that in the blank control,antibiotic, natural Lactobacillus and phytase groups,respectively.The result showed that the nutrient digestibilities of piglets can be enhanced by the transformed Lactobacillus with phytase gene significantly.The results also indicated that nutrient digestibilities of crude fat and dry matter in group D added with transformed Lactobacillus with phytase gene was much more remarkable than that of group E,F and G(P＜0.01).The pH value of group D,E,F and G was lowerer than that of group A,B and C,while the ammonia nitrogen content in faeces was relatively higher than that of group A,B and C.The above results showed that transformed Lactobacillus with phytase gene had some effect on nutrient digestibilities of crude fat and dry matter,and the change of gastro-intestinal environment as well.(3) Effect of the transformed Lactobacillus with phytase gene on plasma biochemical indexes of growing-finishing pigs:The results showed that the transformed Lactobacillus could increase plasma contents of triglyceride(P＜0.05 ),and had no significant effect on other plasma indexes.
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