The Adverse-Resistant Characteristics Of Bacillus Subtilis And Its Influence On Biochemical Indexes Of Piglet And The Ammonia Emission

In pig industry, piglets are prone to have poor health, diarrhea and growth arrest, in severe cases, even death, because of stress, the sudden changes of feed and environmental conditions. For a long time, people made use of antibiotics and antibacterial drugs to solve this problem. However, over use of antibiotics bring serious harm to human health. The residues of antibiotics and drug resistance are becoming increasingly concerned. European Union had prohibited using antibiotics as feed additive in 2006. Meanwhile, large amount of ammonia which produced by pig industry, not only seriously affect the growth of pigs, but also threaten the health of nearby residents. Ammonia in the air is a major reason for the formation of acid rain, and the livestock and poultry production has become the world's largest source of ammonia pollution.Probiotics as one kind of feed additive become a effective alternative of antibiotics because its non-toxicity, no residue and no drug resistance.Bacillus spp. are considered the optimal probiotic because of its strong resistance, easy storage, and other excellent properties. In addition, bacillus spp. can regulate the balance of intestinal flora, enhance animal immunity, improve the growth performance and reduce the emission of ammonia excretion. Bacillus subtilis is one of 16 feed-grade microorganisms which were agree by Ministry of Agriculture. In this study, the adverse-resistant characteristics of a strain of Bacillus subtilis was investigated. perspective of new product development. The process conditions of preparing Bacillus subtilis preparation was studied. Also, the effect of Bacillus subtilis preparation on biochemical indexes of piglet and ammonia emission was investigated. The results obtained are as follows:(1) The adverse-resistant characteristics of Bacillus subtilis test results show:①The survival rate of Bacillus subtilis is close to 80% after treated in 90℃water bath for 10min.②The survival rate of bacillus subtilis is over 83% after treated in artificial gastric juice of pH 2 for 6h;bacillus subtilis grow vigorously when the initial pH value of the medium is 4.0.③The survival rate of bacillus subtilis is over 90% after treated in 0.3% bile salts solution for 4h; The growth of bacillus subtilis was inhibited when medium containing 0.3% bile salts, but bacillus subtilis still can reproduce.⑤rug sensitivity test results show that: bacillus subtilis show high sensitivity to the majority of antibiotics used in the test, low sensitivity of lincomycin.In the view of feed application, these results suggest that bacillus subtilis is one kind of good probiotic with strong resistance.(2) The results of preparation experiment of bacillus subtilis additive show:①The optimal liquid medium is YPD medium, and the optimal fermentation substrate is bran.②The process of bacillus subtilis additive preparation using solid-liquid joint fermentation are:seed culture fluid was inoculated into YPD medium(seed volume 5%), shaking culture for 30h, then culture fluid was inoculated into bran(seed volume 10%) for 30h, then product was obtained after drying and crushing treatment, the product performance are:living bacteria count>1.0×1010cfu/g, spore rate>98%, moisture content<12%。(3)Add 0.1%,0.3% and 0.5% Bacillus subtilis preparation to diet of piglet, investigate its influence on biochemical index and ammonia emission of piglet, the results show:①Daily gain was significantly improved by adding 0.3% and 0.5% Bacillus subtilis preparation,33.7% and 36.8% higher than the control group respectively. Simultaneously, the head feed consumption were significantly increased (P<0.05), and the consumption of feed for each additional lkg live weight were less of 0.38kg and 0.37kg than the control group. The diarrhea rates were lower 6.4%,14.2% and 15.6% than the control group respectively.②IgA content in serum significantly increased(P<0.05), IgG content very significantly increased(P< 0.05)by adding 0.3% and 0.5% Bacillus subtilis preparation. IgM content increased to a certain extent, but there is no significant difference (P>0.05).③The total nitrogen and ammonia nitrogen in urine significantly decreased(P< 0.05) by adding 0.3% and 0.5% Bacillus subtilis preparation, total nitrogen in feces slightly increased, ammonia nitrogen slightly decreased, but there were no significant difference (P> 0.05).④The urease activity of feces significantly decreased(P<0.05) and decreased with the increasing dosage of bacillus subtilis preparation, but there was no significant difference (P> 0.05).⑤The Ammonia concentration of experimental groups reduced 34.1%,48.6% and 50.3% respectively on 36th day.⑥The pH value of feces decreased with the increasing dosage of bacillus subtilis preparation. The pH value decreased from 7.56 to 7.03 when the dosage was 0.5%.⑦In the fermentation test, compared to the control group, ammonia emission of decreased obviously by adding bacillus subtilis preparation. The pH value gradually decreased.