Mechanism Of Mitigating Ammonia Productionin Laying Hens Based On The Regulation Of Coated Sodium Butyrate In Situ

Reducing the concentration of ammonia in layer house is one of the problems that need to be solved in laying hensbreeding.The main source of ammonia is the microbial degradation of uric acid and protein in the cecum and feces.The ammonia emission reduction technology is more aimed at a single site,and can not reduce the ammonia emissions from the cecum and feces at the same time.In this study,the coated sodium butyrate cecum in situregulation,in vitro fermentation test,stability test,gastrointestinal feeding experiment,ammonia production test,16 S rDNAand metabolomics were used to study the effect of the coated sodium butyrate on total amount of ammonia in cecum and faces,microbiology structure in cecum and faces.The mechanism of inhibition of ammonia productionby sodium butyrate was revealed from the microbiology and metabolism.The results are as follows:After adding sodium butyrate and fermentation bacteria source in vitro fermentation syste,we found that: Adding 0.15%,0.20% sodium butyrate decresed the ammonia productionby 34.7%;Urease and uricase activity decreased significantly(P< 0.05);Bacteroides and Faecalibacterium relatively abundance were significantly increased(P < 0.05),the relative abundance of Campylobacter and Helicobacter pylori is significantly decreased(P< 0.05).Comprehensive analysis of the result,0.15% is the best.The release rate of sodium butyrate and coated sodium butyrate in the stomach and small intestine was found by using the bionic digestion system.98.7% powder sodium butyrate is absorbed in the stomach,and the rest of that is absorbed in small intestine;1.9% coated sodium butyrate were absorbed in the stomach and 63.1% coated sodium butyrate were absorbed in the small intestine,the remaining sodium butyrate can enter cacel.Considering the results of chapter two,adding 0.43% sodium butyrate into feedstuff can make sure that 0.15% sodium butyrate reach cacel.A total of 60 laying hens and 12 sets of breath generation were used for researching the effects of coated sodium butyrate cecal ammonia production.The results showed that the average daily ammonia production was decreased to 2.28 mg by adding sodium butyrate.The GRP was 24.6%.Nitrogen deposition ratio was increased significantly in SB treatment(P<0.05);The p H value,activity of urease and uricase,production of valeric acid were decreased significantly(P<0.05);Uric acid,urea,xanthine oxidase and ammonia in blood was decreased significantly(P<0.05);Relative abundance of Bacteroides and Faecalibacterium were increased and relative abundance of Prevotella,Megamonas and Fusobacteriumwere decreased.The composting box was used for static property of ammonia test.The results showed that aftertesting for 8 d,the total amount of ammonia emission is 1.06 g,the GRP was12.0%;The pH of laying hens feces increased slowly,and significantly lower than the control group in 48 h(P < 0.05);the urease activity of treatment group was significantly lower than that of control group in 48 h,72 h,96 h(P< 0.05),uric acid enzyme activity was significantly lower than that of control group in 24 h,48 h,72 h(P< 0.05),the content of valeric acid was significantly lower than that of control group in the 48 h,72 h,96 h(P< 0.05).The total number of bacteria in feces increased before 48 h and decrease after 48 h;The relative abundanceof Lactobacillus and Enterococcus in treatment group were lower than that of control group.Metabonomics technology was used to compare the differences of biochemical composition contents in cecum between treatment group and control group.About 55 remarkable compounds were identified by using OPLS-DA model.After feeding SB,AMP,Xanthine,Glycine,Carbamate,and Cytosinetended to be synthesized less ammonia.More L-Glutamine and Cytosine were used to synthesize proteins.In summary:(1)The 0.43% of the coated sodium butyrate can reach the optimal level of ammonia inhibition.At this level,sodium butyrate could reduce cecal ammonia emissions to 2.28 mg,the GRP is 24.6%;sodium butyrate could improve nitrogen metabolism,inhibit the production of ammonia nitrogen degradation and changes of microbial community structure to achieve the above functions.(2)5 ammonia producing pathway was inhibited in the cecum,which was AMP process,Xanthineprocess,Glycineprocess Carbamate process and Cytosine process in.The total amount of L-Glutamine and Cytosine were used for syntheticing utilization is increased.(3)Feeding sodium butyrate can reduce the ammonia emissions of laying hens to 1.06 g,the GRP was12.0%.During the peak period of ammonia production,the activity of urease and uric acid was decreased significantly(P< 0.05),and the decomposition of uric acid and urea was inhibited(P< 0.05).Sodium butyrate affected the relative abundance of ammonia related microorganisms by changing the microbial community.