Study On Bacteriostatic Effect Of Three Probiotic Combination Fermentation On Pathogens In Vitro

As the abuse of antibiotics has brought serious harm to the sustainable development of animal husbandry and human health,the Ministry of agriculture and rural areas banned the addition of antibiotics in feed in 2020.Therefore,it is urgent to develop new additive products which can effectively replace antibiotics.Probiotics are considered to be candidate products to replace antibiotics in recent years,but there are many kinds of probiotics,and the function characteristics of different strains are different.It has important application value and practical significance to study and select probiotics combination with good bacteriostatic effect for promoting the health of livestock and poultry and promoting the sustainable development of breeding industry.Eight probiotics(Bacillus thuringiensis,Bacillus subtilis,MIA,HSY,Candida tropicalis,Saccharomyces cerevisiae,Lactobacillus plantarum,Enterococcus faecalis)were selected as the standby bacteria in this paper.Three common pathogenic bacteria,Salmonella,Escherichia coli and Staphylococcus aureus,were selected as the objects of inhibition.The strains with better antibacterial effect were screened out through in vitro inhibition,and through a variety of benefits Through the in vitro fermentation experiment,the single factor experiment was carried out on the four key factors of the fermentation process,including the inoculation amount,the ratio of liquid and material,the fermentation temperature and the fermentation time,to further optimize the fermentation process.At the same time,response surface experiment was used to verify the optimized process,and the microbial fermentation feed had no resistance The application of aquaculture provides data reference.The results are as follows:1.Among the 8 candidate strains,beer yeast is the best one.2.Through the combination of different strains and the comparison of antibacterial effect in vitro,the combination of three probiotics,Bacillus subtilis,Mia and Lactobacillus plantarum,has the best effect.Therefore,this combination is selected as the strain for the subsequent fermentation feed test.3.The optimized technological parameters of fermentation feed are as follows: inoculation amount is 6%,liquid feed ratio is 0.9,fermentation time is 72 h,and fermentation temperature is 33 ℃.The response surface experiment further verified that the best antibacterial effect could be obtained under the above fermentation conditions.