Study On High Stress Resistance Of Bacillus Coagulans And Its Application In Weaned Piglets

Abstract:This paper studied the stress resistance of the spores of Bacillus coagulans BCRC11592to heat, acid, bile salt and bacteriostatic ability against pathogenic bacteria, and investigated the influence on cell growth and sporulation rate of incubation time, temperature, initial pH, inoculum and rotation speed. And add the Bacillus coagulans probiotics into the diets of weaned piglets to study its impact on growth performance and serum markers. All these above meant to provide the theoretical basis and data bases for the development and application of probiotics.The results of stress resistance tests showed that the survival rate of the strain were respectively81.9%and79.6%after processing the temperature of90℃and100℃for10min; the survival rate was still more than50%after processing the pH=2.0environment for4h; and the survival rate could reach to79.4%after experiencing the environment with0.3%bile salt for8h. This strain also showed its ability on strong inhibition to E. coli CCRC10306and com pared weaker inhibition to S. aureus CCRC10780.Determine the viable cells number and sporulation rate after fermentation, and take getting the most spores as the final target, optimize the culture condition of this strain from incubation time, temperature, initial pH, inoculum size and shaker speed. The optimal culture conditions were obtained by single-factor test as follows: incubation time24h, temperature40℃, initial pH6.5, inoculum size106cfu, rotation speed140r/min. The number of viable cells reached3.5×10cfu/mL, the number of spores reached3.0×10cfu/mL, and the sporulation rate was85.7%.Using a certain amount of carriers to absorb the liquid broth which was vaccinated the Bacillus coagulans BCRC11592and fermented followed the optimized condition, dried the carriers at45℃and grinded to pass80mesh sieve, then got the Bacillus coagulans probiotics and made the number of spores in probiotics reach109cfu/g. Added this probiotics to the basal diet of weaned piglets according to the added amount0.04%and0.16%, mixed, quenched and tempered, granulate and cooled them. The processing parameters turned out to be mixing time20min, conditioning time10～15s, vapor pressure of0.42to0.54MPae, temperature of the discharge port75to85℃, ring mold compression ratio of12:1, particle size2.0mm of pellet feed. The total survival rate of viable cells during granulation processes in low-dose group and high-dose group are respectively51.25%and57.88%.Eighteen35days old crossbred weaned piglets (Duroc X Landrace X Large White, weight9.15±0.15kg) were assigned to three treatment groups:the control group, low-dose group and high-dose group. Each group contained three repetitions which had two piglets. The test period was28d. The results showed that:Compared to the control group, the daily gain of the high-dose group improved13.81%(P<0.05); both two treatment groups had no significant difference in feed conversion but a overall decline in a significant trend (0.05<P<0.1); the apparent digestibility in organic matter of high-dose group was significant higher than control group (P<0.05); the probiotics could influence the total bilirubin, total cholesterol, and alkaline phosphatase in serum significantly (P<0.05), at the same time was able to reduce the number of fecal E. coli and Salmonella.