Preparation Of A Compound Probiotic Bacterial Agent And Its Application In Lamb Breeding

Probiotics refer to bacteria that colonize the digestive tract of the host and play a beneficial role in prompting the host to change the microecological balance of the body.It is widely used in livestock breeding.The purpose of this experiment is to use the fermented samples collected from the Qinghai-Tibet Plateau,screen the dominant probiotic strains in the Qinghai-Tibet Plateau from the samples,and detect and optimize the production process of probiotic preparations.To obtain a compound probiotic bacterial agent that enhances the number of beneficial bacteria in the gastrointestinal tract of lambs and promotes growth and development.With a view to providing practical support for application development and research in the processing of ruminant products in the future.The main findings are as follows:(1)The strains screened from the fermented foods and feeds on the Qinghai-Tibet Plateau were isolated by streaking on agar medium,morphological studies,biochemical identification and gene sequence analysis of 16S rRNA.Lactobacillus Lactobacillus,Lactobacillus delbrueckii subsp.bulgaricus and Bacillus subtilis are numbered as XH-9,GM-6,GM-7,N-1 respectively;the strains have good growth characteristics and are effective in simulating gastrointestinal fluid in vitro.Good tolerance,and can form obvious inhibition to Escherichia coli and Salmonella.(2)The optimization results of the response surface optimization of the spray drying process of probiotic strains show that:1.Through the spray drying process optimization test,the optimal optimized process conditions of Lactobacillus plantarum XH-9 were obtained as 4%glycerol protective agent addition,600mL/h feed rate and 150℃ inlet temperature,and the optimized strain survival rate was 44.90%.2.Through the optimization test of spray drying process,the optimal process conditions of Lactobacillus rhamnosus GM-6 were obtained as 2%glycerol protective agent addition,110℃ inlet temperature and 60℃ outlet temperature,and the survival rate of the optimized bacteria was 29.1%..3.Through the optimization test of spray drying process,the optimal process conditions of Lactobacillus delbrueckii subsp.bulgaricus GM-7 are obtained as the addition of glycerin protective agent 3%,the inlet temperature 110℃ and the outlet temperature 60℃,the survival rate of the optimized bacteria is 27%.4.Through the optimization test of spray drying process,the optimal process conditions of Bacillus subtilis N-1 were obtained as feed rate 600mL/h,inlet temperature 95℃ and outlet temperature 55℃,and the survival rate of bacteria after optimization was 78.8%.(3)The experiment was divided into three treatment groups by single-factor randomized experimental design:1)control group(CK);2)probiotic feed additive group(Probiotics group);3)commodity control group(Business group).The trial period was thirty-five days.The test results showed that:1)Supplementing probiotic feed additives could slightly improve the feed conversion rate of lambs;2)Feeding probiotics could improve the physiological,biochemical and blood indexes of lambs,and the compound probiotics were better than single in blood indexes.3)The high-throughput sequencing results of the microbial flora in lamb feces found that feeding probiotic feed additives could increase the abundance of probiotics in the gastrointestinal tract of lambs.At the same time,the colonization ability of the compound probiotic strains in the gastrointestinal tract is better than that of a single strain,and it has a strong inhibitory effect on some bacteria and actinomycetes,which has the possibility of enhancing the abil-ity of the gastrointestinal tract of lambs.The above studies preliminarily show that adding the compound probiotic feed additive can be beneficial to the establishment of probiotic flora in the gastrointestinal tract of lambs.