Study On Ettects Of Synbiotics On Growth And Microbial Enviroment In Broilers

The trail was conducted to investigate the supplementation synbiotics combination of Bacillus subtilis, xylooligosaccaharide and mannanoligosaccharide in broilers, compared with probiotics, prebiotics and antibiotics. We systematically analyzed the indexes of growth, nutrinent digestibility, immune and antioxidant functions, intestinal histomorphology and dynamic changes of microbial flora in broilers. Experiment 1 was conducted to evaluate the effects of synbiotics(combination of Bacillus subtilis, xylooligosaccaharide and mannanoligosaccharide) on growth performance, intestinal histomorphology and immunity, antioxidant funcion and nutrient digestibility of broiler, compared with probiotics (Bacillus subtilis), prebiotics (Xylooligosaccaharide and mannanoligosaccharide), antibiotics (Xanthomycin). Four hundred and fifty 1-d-old"Cobb 48"broiler chicks were randomly assigned to 1 to 5 dietary treatments, and fed the diets containing basal diets, antibiotics, probiotics, prebiotics and synbiotics. Each treatments allocated to 3 replicates. The supplementation of synbiotics significantly improved average daily gain (ADG) and feed conversion compared with control, antibiotics, probiotics and prebiotics (P<0.05). Synbiotics supplementation increased (P<0.05) villus height : crypt depth ratio and villus height in duodenum, jejunum and ileum. However, the duodenum and ileum were decreased by dietary contain synbiotics compared with control. Furthermore, on 21 day and 42 day, the mucosal sectory IgA in intestinal were improved by synbiotics compared with other supplemention and control (P<0.05). Dietary supplemental synbiotics improved digestibilities of Ca and P (P<0.05). Addition of synbiotics significantly increased plasma superoxide dismutase (SOD) levels and lysozyme activity (P<0.05), however, the plasma malondialdehyde (MDA) levels were decreased in synbiotics-fed group (P<0.05). Experiment 2 was conducted to investigate the effects of synbiotics in broiler diets on the cecal microflora ecology using denaturing gradient gel electrophoresis(DGGE) techniques and real time-PCR. The number of PCR-denaturing gradient gel electrophoresis bands of synbiotics-fed group was higher than those in the control, antibiotics, probiotics and prebiotics groups. Gene sequences analysis indicated that the specific bands were mainly uncultured bacteria in cecum of broilers. Dietary synbiotics increased the populations of total bacteria, Lactobacillus, Bifidobacterium and decreased the number of E.Coil, the effect was consistent with the improvements of growth performance. The above research results indicate that supplementation of synbiotics compared with probitics, prebiotics, antibiotics alone, could improve growth performance of broiler, this effect has relationship among the effects of synbiotics in enhancing immunomudulatory functions and antioxidant, improving intestinal histomorphology, increasing diversity of microorganisms in broiler cecum, and promoting the proliferation of lactobacillus and bifidbacterium , decreasing the number of E.Coil.