Screening Of Uric Acid Oxidase Producing Strains And Its Application In Poultry Hyperuricemia

Hyperuricemia is a disease characterized by abnormally elevated serum uric acid levels.Biologically hyperuricemia occurs when serum uric acid levels exceed urate solubility.In extreme cases,persistently high levels of uric acid occur.Uric acid levels can lead to hyperuricemia(Hyperuricemia,HUA),whose typical damage includes inflammation,oxidative stress,and intestinal dysbiosis.Primates and birds have higher serum uric acid levels than other animals due to missense mutations in the uricase gene and are therefore more prone to hyperuricemia.In order to alleviate and treat hyperuricemia in poultry,this study intends to screen out strains with high activity of uric acid oxidase,and feed them through feed to reduce the concentration of uric acid in the intestinal tract,increase the secretion of intestinal uric acid,and reduce the reabsorption of intestinal uric acid,so as to prevent the and the purpose of treating HUA in poultry,the main findings are as follows:1.Based on the ability of urate oxidase-producing strains to produce urate oxidase transparent circles on the uric acid screening medium,a total of 56 urate oxidase-producing transparent circles were screened.Microscopic observation results can be divided into four categories of strains screened.The ability of screening strains to produce uricase was evaluated by H/C value(diameter of transparent circle/colony diameter).7.75±0.25,of which 13 strains had HC values over 4.00,12 strains had 2.00<HC<4.00,and the remaining 31 strains had H/C less than 2.00.The enzymatic activities(protease and amylase)of the screened strains were determined by plate spotting method.The results showed that only strain d36 had the ability to produce protease among the screened strains;The strains d26,d24,d18,d44,d33,c7,and c4 have the ability to produce amylase.2.The homology comparison of the sequencing results through the NCBI website shows that among the 27 identified strains,15 belong to the genus Alcaligenes.The phylogenetic tree of strain AS1 and strain P56 was constructed using MEGA.7.0 software.The results showed that strain AS1 had the highest homology with Alcaligenes faecalis,and strain P56 had the highest homology with Pseudomonas guariconensis.The highest homology.The growth characteristics of the strain were reflected by measuring the OD600 of the bacterial suspension.The results showed that the strain AS1 reached the logarithmic phase at 10h and entered the plateau phase at 24h;the strain P56 reached the logarithmic phase after 4h and entered the plateau phase after 20h.3.Use adenine,uric acid,and ethambutol to assist,construct a hyperuricemia model through enteral administration,and screen the modeling drugs and doses according to serum uric acid and creatinine concentrations.The results showed that on the 5th day of administration of the hyperuricemia model,the serum uric acid concentration in the high adenine combined with ethambutol group(AE-H group)showed an increasing trend compared with the blank control group.The group exhibited the highest serum uric acid concentration.On the 9th day,this trend is more obvious.In order to optimize the dose of adenine,a series of doses of adenine(550,650,750,850,950 mg/kg B.W)were set and combined with ethambutol(125 mg/kg B.W).The results showed that on the 4th day,the serum uric acid concentration of the adenine 550mg/kg B.W administration group was not significantly different from that of the control group;the serum uric acid concentration of the 650 mg/kg B.W administration group was significantly increased(p<0.05);The serum UA concentration in the 950mg/kg B.W administration group was significantly increased(p<0.01),and the latter two high-dose groups died on the 4d,so the follow-up experiment used the administration dose of 750mg/kg B.W.to construct duck hyperuricemia Model.4.The safety observation test of test strains AS1 and P56 on healthy ducks showed that the test strains AS1 and P56 were not pathogenic and had no negative impact on the health of ducks.The test results of reducing the serum uric acid concentration of the HUA ducks with the test strains showed that at 4d,when the AS1 strain was fed with the feed at the same time,the serum uric acid concentration could be significantly reduced;while the feed with the strain P56,the serum uric acid concentration had no effect.Significant differences.Through previous experiments,AS1 was determined to be a high-efficiency strain,so its therapeutic effect on ducks with hyperuricemia was explored.The CON group was given 5%CMC-Na colloidal solution by gavage,and the AE group and AE-AS1 group were given adenine(750mg/kg B.W)+ethambutol(125mg/kg B.W)by gavage;CON group and AE group The rats in the AE-AS1 group were fed with the normal feed,and the AE-AS1 group was fed with the AS1 bacterial liquid feed at a concentration of 2.1×10~9CFU/kg.The experiment ended on the 4th day.The results showed that the serum uric acid concentration in the AE group and the AE-AS1 group was higher than that in the CON group,and the serum uric acid concentration in the AE-AS1 group was significantly lower than that in the AE group(p<0.01),and the serum BUN and ALT concentrations in the AE-AS1 group were significantly lower than those in the AE group(p<0.01);AE-AS1 and AE groups had large amounts of urate in feces,and white urate was also observed in kidney histological sections.It can be seen from the above results that strains with high uric acid oxidase production can be screened from duck feces.Most of the strains are identified as Alcaligenes,and one of them,AS1,is used to treat ducks with hyperuricemia by feeding them.It can significantly reduce the serum UA concentration at 4d,and has a certain alleviation effect on the kidney damage caused by HUA.