Effects Of Sodium Acetate On Diarrhea In Newborn Calves

Diarrhea in newborn calves is widespread,which seriously affects the healthy development of the cattle industry.Previous studies have shown that acetate can increase the production of Ig A in the gut,altering how Ig A reacts with specific intestinal flora.However,whether sodium acetate plays a role in alleviating calf diarrhea by regulating intestinal flora is unclear,and we need to study it urgently.In this study,the effect of sodium acetate on diarrhea in newborn calves was first studied,and then based on DSS-induced mouse intestinal inflammation model,combined with 16S r DNA sequencing,the effect of sodium acetate in alleviating diarrhea was studied based on intestinal microorganisms,which provided reference data for alleviating diarrhea in calves.The experiment is divided into two parts:Experiment 1 Effects of Ace Na on diarrhea in newborn calvesFirstly,three common pathogenic bacteria,Escherichia coli K88,Salmonella SA083and Staphylococcus aureus were selected to carry out the in vitro bacteriostatic test of sodium acetate by the antibacterial circle method,and the result showed that sodium acetate could significantly inhibit the growth of the above three pathogens.Followed by animal testing,Twenty newborn Holstein calves（7 to 8 days of age）were randomly divided into 2groups,control（CON）group and sodium acetate（Ace Na）group,with 10 replicates in each group.The CON group was fed milk substitute powder every day,and 50 m L of PBS was gavaged every other day,and feces were collected and photographed and scored the next day.The Ace Na group was fed milk substitute powder every day,and sodium acetate was fed 5g/d every other day,and feces were collected and photographed and scored the next day,and the test was carried out for 28 days.After the test,the blood and stool samples collected are analyzed for biochemistry and microbiology.Compared with CON group,the calves in Ace Na group had a significant decrease in body weight,a significant decrease in the rate of diarrhea and diarrhea index（P<0.05）,and a significant decrease in serum pro-inflammatory factors IL-1β（P<0.05）,IL-6（P<0.05）,IL-8（P<0.01）and IL-17A（P<0.05）,and significantly increased the inflammatory factor IL-22（P<0.05）.The contents of Ig A（P<0.05）,Ig G（P<0.01）were significantly increased,CAT was also significantly increased（P<0.05）,and MDA was significantly reduced（P<0.05）.The results showed that Ace Na significantly inhibited the intestinal inflammatory response,thereby effectively alleviating diarrhea.The results of 16S r DNA sequencing showed that compared with the control group,the Ace Na group significantly increased the relative abundance of Bifidobacterium,Dorea and Faecalibacterium,and decreased the relative abundance of Alloprevotella and Bacteroides.LEf Se analysis identified the dominant flora of the Ace Na group,namely B.pseudocatenulatum,F.pleomorphus and F.prausnitzii,significantly increased the relative abundance of B.pseudocatenulatum（P<0.05）,D.formicigenerans and F.prausnitzii（P<0.05）.At the same time,Ace Na also significantly increased the content of acetic acid（P<0.001）and propionic acid（P<0.05）.The results of the first experiment showed that Ace Na had a therapeutic effect on diarrhea in newborn calves,and regulated the intestinal flora and alleviated intestinal inflammation.Experiment 2 Effect of Ace Na on DSS-induced gut inflammation in miceThirty SPF C57BL/6 mice were randomly divided into CON group,DSS group and Ace Na group.The DSS group and the Ace Na group drank sterile water containing 3%DSS（w/v）freely from the 15^th day to 21^th day,and gavaged 300μL of Ace Na（50 mg Ace Na/kg BW）every day from the 1^th day to 21^th day in the Ace Na group;CON group gavaged 300μL of sterile water daily for a test period of 21 days.All mice are sacrificed on the 22^th day to measure colon length and biochemical analysis of collected blood and fecal samples.The results showed that compared with the CON group,DSS group had significant intestinal inflammation,DAI index（P<0.01）,spleen index decreased,colon length increased significantly（P<0.05）,and pathology score significantly decreased（P<0.001）after Ace Na treatment.In addition,the MPO and inflammatory factor IL-1βin the Ace Na group were significantly lower than those in the DSS group（P<0.05）,and the inflammatory factor IL-22 was significantly higher（P<0.05）.Determination of short-chain fatty acids showed that Ace Na significantly increased acetic acid（P<0.01）and propionic acid（P<0.05）content in intestinal contents.Conclusion:Ace Na can relieve calf intestinal inflammation and calf diarrhea;Ace Na may increases the abundance of B.pseudocatenulatum,D.formicigenerans and F.prausnitzii,increases the concentrations of acetate and propionate in the intestine,reduces pro-inflammatory factors and increases the expression of anti-inflammatory factors to exert anti-inflammatory and antidiarrheal effects.