Effects Of Probiotics Derived From Duck On Digestive And Intestinal Immune Function Of Tianfu Sheldrake

The purpose of this experiment was to investigate the effects of duck-derived probiotics on the growth performance,digestive enzyme activity,serum immunoglobulin content,Toll-like receptor protein expression and microbial community composition of the cecum of Tianfu sheldrake.The intestinal contents of healthy ducks were first selected,probiotic bacteria were isolated,identified and screened,and Bacillus and Lactobacillus were expanded and cultured to obtain the probiotics required for subsequent trials.Sixty-six eight-day-old Tianfu sheldrake were randomly divided into three groups with two replicates in each group and eleven ducks in each replicate.The normal group was fed the basal diet,the Bacillus group was supplemented with Bacillus of 10¹¹cfu per kg in basal diet and the Lactobacillus group was supplemented with Lactobacillus of 1011 cfu per kg in basal diet,respectively.The experimental period was 20 days.The average daily gain,average daily feed intake,ratio of feed to gain were recorded,and serum was collected at 0,10 and 20 days of the trial.On day 20 of the experiment,three ducks of similar weight were selected from each group and slaughtered.Tissue samples were collected aseptically,and digestive enzyme activities and serum immunoglobulin content were detected by ELISA kit.Intestinal contents were detected by high-throughput sequencing,q RT-PCR and Western blot.The results showed that:（1）The effect of duck-derived probiotics on the growth performance of Tianfu sheldrake.The average weight of the Bacillus and Lactobacillus groups was significantly higher（P<0.05）,the average daily gain of the Bacillus and Lactobacillus groups was significantly higher（P<0.01）and the ratio of feed to gain of the Bacillus and Lactobacillus groups was significantly lower（P<0.05）compared to the control group on the 20th day of the trial.（2）The effect of duck-derived probiotics on the activity of intestinal digestive enzymes in Tianfu sheldrake.On the 20th day of the experiment,the amylase activity of the Lactobacillus group was significantly higher than that of the control group（P<0.05）;the lipase activity of the Lactobacillus group was significantly higher than that of the control group and the Bacillus group（P<0.05）.（3）The effect of duck-derived probiotics on the intestinal flora of Tianfu sheldrake.By high-throughput sequencing analysis,the number of OTUs obtained from duck cecum samples in the normal,Bacillus and Lactobacillus groups was 884,with 133,189 and 293detected in each group,respectively,in which 104 OTUs（11%）were shared;155 OTUs（17%）were shared between the normal and Bacillus groups;208 OTUs（23%）were shared between the normal and Lactobacillus groups.The Bacillus and Lactobacillus groups had higher intestinal flora abundance values compared to the control group,and the ratio of beneficial to pathogenic bacteria was significantly different between the groups（P<0.05）.（4）The effect of duck-derived probiotics on immunoglobulins in the serum of Tianfu sheldrake.Compared with the normal group,the serum levels of Ig A,Ig G and Ig M in the Lactobacillus group were highly significant（P<0.01）and the serum levels of Ig A in the Bacillus group were highly significant（P<0.01）compared with the control group on the20th day of the test.（5）The effect of duck-derived probiotics on intestinal TLR 3/TLR 4/My D 88/IRF 3receptor proteins in Tianfu sheldrake.Compared to the control group,TLR 4,TLR 3,My D88 and IRF 3 protein contents were significantly higher in the Bacillus group（P<0.05）and TLR 4,My D 88 and IRF 3 m RNA relative expression was significantly higher in the Lactobacillus group（P<0.05）,TLR 4,TLR 3,My D 88 and IRF 3 protein expression and m RNA relative expression were significantly higher in the Lactobacillus group compared to the control group（P<0.05）.The expression of TLR 4,TLR 3,My D 88 and IRF 3proteins and the relative expression of m RNA were significantly increased in the Lactobacillus group compared with the control group（P<0.05）.In conclusion,probiotics can promote the secretion of digestive enzymes in the intestinal tract of Tianfu sheldrake,improve growth performance,maintain the diversity and structural stability of the intestinal flora,and enhance the immune level of the organism by enhancing the Toll-like receptor pathway and increasing the levels of serum immunoglobulins.