Effects Of Different Lactic Acid Bacteria Cultures On Growth Performance And Immunity Of Broilers

The study was conducted to investigate the effect of different lactic acid bacteria cultures on performance, digestive function, cecal microorganism, immune function, antioxidant properties and serum biochemical indexes of broilers. In this study the orthogonal experiment method was conducted; three kinds of lactic acid bacteria cultures were selected. The effect on pathogenic bacteria by measuring the inhibitory activity of lactic acid fermentation liquid with stronger inhibition was done.Completely randomized experimental designs(CRD) with 300 one-day-old AA broilers with a similar weight, were randomly assigned to five treatment groups. The control group(C) was fed basal diet. Antibiotic group(A) were added 0.01% chlortetracycline to the basal diet, the experimental group L1, L2, L3, respectively, were added 0.16% lactic acid bacteria cultures L1, L2, L3 to the basal diet. Each treatment had six replicates with ten birds per replicate. Trial period for 42 days, on 21 days and 42 days of age birds were slaughtered for sampling. The results showed that diets supplemented with lactic acid bacteria culture L1 significantly improved the average daily intake(P<0.01) and F/G(P<0.05) of broilers. Lactic acid bacteria culture L3 significantly improved average daily gain in early stage(P<0.01). Lactic acid bacteria cultures L1 and L2 significantly improved average daily gain in late stage(P<0.01). Lactic acid bacteria culture L1 significantly improved immune organs index, concentration of acetic acid in cecum and SOD in serum of broilers in early stage(P<0.05), liver and pancreas index, phosphorus digestibility(P<0.05), the number of total protein and globulin and ALP in serum(P<0.01) in late stage. Lactic acid bacteria culture L2 significantly improved the number of total protein and globulin in serum of broilers in early stage(P<0.01), liver index throughout the trial period, immune organs index, concentration of propionic acid and total volatile fatty acid in cecum, Newcastle disease antibody titers, T-AOC and ALP in serum of broilers in late stage(P<0.05). Lactic acid bacteria culture L3 significantly improved crude fat digestibility, spleen index and SOD in serum of broilers in early stage(P<0.05), pancreas index, IgA levels in serum in late stage(P<0.05) and ALP in serum throughout the trial period(P<0.01). Diets supplemented with lactic acid bacteria cultures significantly reduced the number of lactobacilli(P<0.05) and the number of E. coli(P<0.01) in cecum, and significantly increased the number of bifidobacteria and in late stage apparent deposition rate of nitrogen(P<0.05).In summary, addition of inactivated lactic acid cultures in the diet can improve the performance of broilers. The antibacterial effect of L3 is best. The dosage of L3 in early stage is suitable, the dosage in late stage should be reduced. The antibacterial effect of L1 and L2 is poorer. The dosage of L1 and L2 in early stage should be increased, the dosage in late stage is suitable. In poultry production, 0.16% inactivated lactic acid bacteria cultures are available to replace antibiotics, so as to achieve better economic results.