Effects And Mechanism Of A Dried B. Subtilis Culture On Performance Of Layers

Experiment 1: Application of Bacillus as feed supplementation in layersNine hundred sixty 25-week-old Lohmann layers divided randomly into 5 groups of 192 layers each were conducted to evaluate the effects of a dried Bacillus culture on performance and egg qualities of layers. Layers in treatment 1 was fed a basal diet; the other treatments were fed a basal diet +20mg/kg zinc bacitracin+4mg/kg colistinsulfate^ 0.05% Bacillus culture % 0.10% Bacillus culture ^ 0.15% Bacillus culture, respectively. The result of this study showed that there was an improvement in egg production (p>0.05) , feed consumption and feed efficiency of layers when 0.05% Bacillus culture was added to the diets; and there was also an increase in egg shell thickness, yolk color, Haugh unit, and yolk cholesterol concentration; 0.05% Bacillus culture group and antibiotics group significantly reduce the population of total bacteria, Escherichia coli, and Salmonella on the shell surface of eggs and inside the eggs (p<0.05) . Excessive dose of Bacillus culture did not improve performance of layers.Experiment 2: Tolerance test between Bacillus and antibiotics and the effect of high-temperature on BacillusThe experiment was conducted to determine the influence of temperature and antibiotics on Bacillus. The temperature had little effect on Bacillus livability, Bacillus had few loss during feed processing; there had a relative large tolerance between Bacillus and frequently used antibiotics.Experiment 3: Mechanism of Bacillus culture as an alternativeOne hundred twenty 46-week-old layers divided randomly into 5 groups of 24 layers each were used. The result showed that there was an significant improvement of cecum microflora balance in the Bacillus culture group, and the population of enteropathogenic microorganism in cecum was found a significantly lower; metabolic production of Bacillus decreased the population of Escherichia coli and Salmonella in vitro (p<0.01) .