Preparation Of Feed Additives By Probiotic Fermentation Of Poria Cocos Residues And Its Biological Activity

In recent years,antibiotics have been widely used in animal husbandry.At the same time,the abuse of antibiotics has become more and more intense,and its negative effects have become increasingly significant.To this end,the Ministry of Agriculture and Rural Affairs of our country announced the implementation of the "ban on resistance." Therefore,finding and developing feed additives that can effectively replace antibiotics has become a research hotspot in the current animal husbandry industry.Chinese herbal medicines and probiotics have become reliable alternatives to antibiotics because of their immune enhancement,growth-promoting and antibacterial effects.Studies have found that combining Chinese herbal medicines and probiotics for biological fermentation can produce 1+1> 2 effects after fermentation.Poria cocos(Schw.)Wolf is included in the catalog of feed ingredients in China as a natural plant for feed.The polysaccharides and triterpenoids contained in it can enhance animal immunity,and it has been well used in feed additives.Poria cocos(PC)is also a raw material of many kinds of prescriptions and Chinese patent medicines.There is a saying of "Shi Fang Jiu Ling".The production volume of the enterprise is large,so a large number of PC residues were produced.Due to the restriction of the extraction process,the PC residues still contain some medicinal and nutritional active ingredients,which can be used as feed additives.Studies have shown that biological fermentation is the most potential processing technology for the development and utilization of traditional Chinese medicine residues feed resources.In this study,the residue produced during the production of PC formula granules was used as raw material,and probiotics which could be used as feed additives were selected for solid-state fermentation,in order to prepare feed additives at the lowest energy consumption and cost input,and provide ideas for the study of effective substitutes for feed antibiotics.The biological activity of fermented PC residues were evaluated from antioxidant and immune regulation aspects by biological and cell experiments,which provided experimental basis for its development and application in animal breeding.At the same time,it can realize the transformation of residuesinto treasure,solve the problem of residues treatment in traditional Chinese medicine enterprises,and achieve the purpose of harmonious development of economic and ecological benefits.The specific research content and results of this article are as follows:(1)Screening of strains of fermented PC residues and optimization of fermentation technology Twelve kinds of probiotics that can be used as feed additives are selected as fermentation strains,and PC residues were used as a medium for solid-state fermentation.Analyze the growth of 12 kinds of probiotics in PC residues by live bacteria counting method,and screen out the best fermentation bacteria.Taking the number of viable bacteria in the fermentation product as the response value,based on the single factor experiment,the response surface optimization method was used to study the best fermentation strains for solid-state fermentation of PC residues to optimize the fermentation conditions.The strain that has the best growth in PC residues selected in this study is Lactobacillus casei sp.(Lactobacillus casei sp.).The optimal fermentation process after response surface optimization is:the ratio of material to water is 1:1.45,the inoculation amount is 8%,the fermentation time is 41 h,and the fermentation temperature is 25.5℃.Under these conditions,the number of viable bacteria in the fercentation product is estimated to be 1.29×108CFU/g.It has been verified that the optimization results are reliable,and the fermentation process can be used in practice.(2)Substance analysis of probiotics fermented PC residues Different analysis and testing methods were used to analyze the fermentation products under the optimal technological conditions from three aspects:medicinal components(PC polysaccharide,pachymic acid),nutritional components(protein,crude fat,ash,crude fiber,phosphorus,calcium)and safety and health indicators(heavy metals,Salmonella).The results showed that the content of PC polysaccharide,the active medicinal ingredient after fermentation,was significantly decreased by14.49% compared with that before fermentation,and the content of pachymic acidwas significantly increased by 9.09% compared with that before fermentation.The main nutrients,protein,crude fat,ash,crude fiber,phosphorus and calcium increased by 31.90%,131.33%,18.36%,18.81%,50.00% and 94.06%,respectively,all showing an increasing trend,and the nutritional value was improved.The heavy metals arsenic,lead,cadmium and microbial Salmonella in the fermented PC residues were not detected,and the content of heavy metal mercury was within the safety requirements.The PC residues fermented with probiotics met the feed safety requirements.(3)Research on the biological activity of fermentation products The antioxidant capacity of three different antioxidant indexes(DPPH,hydroxyl group and ABTS free radical scavenging)was compared between residues and fermentation products of PC residues.The results showed that the antioxidant capacity of PC residues were improved by Lactobacillus casei fermentation.The proliferation ability of RAW264.7 macrophages was detected by CCK-8method.Phagocytosis was detected by neutral red method.Griess assay was used to detect the ability of cells to release nitric oxide(NO).The results showed that PC residues had better immune activity after fermentation than before,and could significantly enhance the proliferation,phagocytosis and NO release ability of macrophages.In conclusion,from the 12 kinds of probiotics that can be used as feed additives,one strain was screened out which was most suitable for growing in PC residues,and the optimal fermentation process was determined.The contents of medicinal and nutritional components in the fermentation products of PC residues were determined and their safety was evaluated.On this basis,the antioxidant and immunomodulatory activities of the fermented products of PC residues were studied.This study provided data support for the development and application of fermented PC residues to prepare feed additives,and also provided research ideas for the utilization of PC residues.