Study On Antibacterial Function Of Bioactive Peptides Derived From Sheep Blood

In this experiment,the bioactive peptides were extracted from the hemoglobin of sheep blood by protease enzymolysis(A,B,C,D).The vitro antibacterial effect of bioactive peptides from sheep blood were tested on Salmonella,E.coli and E.coli K88,and the rat model with high diarrhea pathogenic bacteria was established.The in vivo antibacterial test to K88 was carried out with bioactive peptides from sheep blood in order to provide a scientific basis for the utilization of bioactive peptides from sheep blood.The results are as follows:1.After treatment with protease A,B,C and D,the bioactive peptide obtained by enzymatic hydrolysis of A protease for 4h appeared bacteriostatic circle with diameters of 11.58±2.13mm for Salmonella,12.9±2.45mm for common Escherichia coli and E.coli K88 14.45±0.71mm,respectively.The minimum inhibitory concentrations were 18.27 μg/mL for Salmonella,18.27 μg/mL for ordinary Escherichia coli and E.coli K88 36.54 μg/mL,respectively.In the cell membrane permeability test,with the increase of time,the effect of bioactive peptide obtained by enzymatic hydrolysis of A protease for 4h on the cell permeability of the three bacteria was also enhanced.In the cell surface hydrophobicity test,there was no significant difference between the experimental group and the acid chloroform group(P＞0.05),and it was confirmed that the bioactive peptide obtained by enzymatic hydrolysis of A protease for 4h was acidic.In the culture medium protein concentration test,the number of cell membranes destroyed increased with time and reached the peak at 6h.2.Through the determination of mortality and fecal colony count,the optimal concentration of bacteria was 3 X 108 CFU/ml,and the best time was 15 days.3.Selected 30 kunming rats,it can be divided into blank control group,negative control group(take A peptide),positive control group(irrigation suits bacteria suspension),experiment group 1(after bacteria suspension pouring irrigation first take A peptide),test 2 groups after A peptide(first take bacteria suspension),and five different treatment group on the rat feed intake,body weight and blood routine index there was no significant difference(P>0.05);At the 15th day of the experimental period,the number of fecal colonies in the five treatment groups was significantly different(P<0.05).The difference between the spleen-positive control group and the other 4 treatment groups was significant(P<0.05),and there was no significant difference between the 5 thymus index treatment groups(P>0.05).In HE staining,E.coli K88 suspension was given with different degrees of damage to intestinal tissue,and there were significant differences in villi length and crypt depth in the small intestine(P<0.05).The bioactive peptide obtained by gavage hydrolysis of A protease for 4h in rats could reduce the expression levels of TNF-and IL-6 genes in jejunal homogenate.In conclusion,the bioactive peptides obtained by enzymatic hydrolysis of a protease for 4 h have a certain scavenging effect on the high pathogenic environment in rats caused by E.coli K88,and can slow down the damage of intestinal tract by E.coli K88.Therefore,the biological antimicrobial peptides from sheep blood have good antibacterial effect in vivo and in vitro,and have the value of being developed.