Study On The Sceening Of High Ability Enzyme-Producing Strain Of Bacillus Spp And The Application In Milk Cows

The experiment was conducted to evaluate the effect of high ability enzyme-producing strain of Bacillus spp on milk yield and milk composite. Extracellular enzymes of 10 strains of Bacillus spp were mensurated by decoration method on agar medium at the first sceening and spectrophotometric method at the final sceening. Under the optimized condition of culture, the enzyme activity of the Bacillus Subtilis PabO2 is more than other strains, and enzyme activity is equable by successive fermentation. Extracellular proteinase, cellulose and amylopectase activity reach 446.889U, 1582.854U and 31.331 MMU respectively.Direct-Fed-Microbial (DFM)-Bacillus subtilis PabO2 produced by fermental principle was selected in order to animal experiment. Twenty-four delivered black-and-white cows with similar fetuses ages and milk yields were randomly divided into four equal groups under the same feed formula, management and environmental conditions with different in quantity of Bacillus subtilis as treatment groups and without Bacillus subtilis as control group, DFM control group A, DFM adding group B (1×10⁹cfu/day/cow) , DFM adding group C (5×l0⁹cfu/day/cow) , DFM adding group D (2×l0¹⁰cfu/day/cow) .The effect of different dosage DFM on milk yield, milk butterfat, milk protein, milk solids-not-fat and milk density was evaluated.The results show that DFM-Bacillus subtilis PabO2 is able to improve average milk yield. The average milk yield was compared in experimental stage with in pre-experiment stage within the same group, the milk production in experimental stage of the treatment groups and the control group are improved. But compared with the control group A, the treatment groups C and D increase by 26.34% and 20.53% respectively. During the same experimental period, the variances between the three treatment groups with Bacillus subtillis-adding and the control group are significant. The variance between treatment group C and the control group A is significantly high( P<0.01), and the variance between the treatment group C and the treatment group B is significant (P<0.05) on the 3th...