The Probiotic Properties And Safety Evaluation Of Enterococcus Faecium

Probiotics are widely used in animal husbandry production as feeding additives.The effects of probiotics were acknowledged by livestock practitioners and relative scholars.The probiotic characteristics are varied from strains since it is important to screen more probiotics.We had preserved a strain coccus which was high anti-bile isolated from the bile of chicken.This paper made a systematic prebiotics evaluation to the coccus.The concrete research was as follows:(1)Species identification was carried out by phenotypic experiments and genotyping experiments.The strain was determined as Enterococcus faecium by morphological,physiological and biochemical characteristics and 16 S rDNA sequence alignment.The Enterococcus faecium isolated was named as SQ-1.(2)Explore the probiotic characteristics of SQ-1 in vitro.The results showed SQ-1 had great properties of probiotic.The probiotic properties were as follows: resistance of acid,resistance of bile salts,resistance of high temperature,resistance of digestive enzymes,hydrophobicity and antibacterial properties in vitro.The resistance test of SQ-1 showed that the survival rate was 61.93% in the environment of PH 2.0 for 3h.The survival rate was 49.70% in bile salt concentration of 0.6% for 3h.The survival rate was 77.66% in 60? for 15 min and 31.01% in trypsin treatment(1.2%)for 3h.These results showed that SQ-1 ha great ability of anti-resistance,especially to the high concentration of bile salt.SQ-1 had moderate antibacterial ability after we did the antibacterial test of CVCC 3377 Salmonella(11mm inhibition zone)and CICC 23926 Staphlococcus aureus(13mm inhibition zone).(3)Studies the influences of SQ-1 to the phagocytosis of mice and increasing of IgG and IL-2 in serum.The results of carbon clearance test showed that it had significant increasing of carbon clearance(P<0.05)to feed SQ-1(1×109 cfu/ml)compared to the normal saline control group,which indicated that SQ-1 had a significant effect on the phagocytosis of mice.The test of IgG in serum of mice which were taken orally SQ-1 showed that IgG significantly increased(P<0.01)in high dose group(1×109 cfu/ml)compared to control group.The levels of IL-2 in serum had no significant differences between SQ-1 group and control group.The results indicated that SQ-1 increased the immunology of mice significantly.(4)The safety studies of SQ-1 were composed of virulence gene test,sensitive test of 20 kind antibiotics,organ index detection and pathological observation.SQ-1 was sensitive to 8 kinds of antibiotics,especially to vancomycin(inhibition zone:19mm).The result indicated that SQ-1 had good safety on antibiotic resistance.We test six virulence factor gene(Asa1,cyl A,efaA,esp,gelE,hyl)by PCR,the result showed that the six virulence factor genes were absent in SQ-1.There was no significant difference in organ index and pathologic changes on the safety test between the control group and the experimental group.These results all indicated that SQ-1 had good safety.In summary,enterococcus faecium SQ-1 had good probiotic characteristics of acid resistance,bile tolerance and digestive enzymes resistance.At the meanwhile,SQ-1 had good property of safety.All these results provided theory evidence of production and also indicated the good application prospect of SQ-1.