Effect Of Enterococcus Faecalis Replacing Of Dietary Antibiotics On Performance, Immunity, Intestinal Development And Intestinal Microflora Of Nursery Pigs

In order to avoid the abuse of antibiotics in pig production, seeking alternatives to antibiotic additives is a hot research topic now. In this paper, we studied the effect of Enterococcus faecalis replacing of dietary antibiotics on growth performance, diarrhea, immunity, digestibility of feed, intestinal structure and intestinal microbes, in order to provide a theoretical basis for the use of Enterococcus faecalis in the production of nursery pigs. Total of 150 nursery pigs, weaned at 25 days of age (8.41±0.17Kg, Duroc×Landrace×Yorkshire) were randomly divided into five groups. Pigs in control group were fed with basal diet. Those in treatment group were fed with basal diet supplemented with 100g/T Enterococcus faecalis group (treat I),200g/T Enterococcus faecalis group (treat II),400g/T Enterococcus faecalis group (treat III) respectively. Pigs in possitive control group were fed with basal diet supplemented with legal antibiotics. Each group had four repeats. The experiment was divided into three parts:1 Effect of Enterococcus faecalis replacing of dietary antibiotics on the growth performance, diarrhea rate and blood immune of nursery pigsThe growth performance and diarrhea rate of nursery pigs were measured at stages of 1-14 days and 15-28 days. The content of the serum immunoglobulin IgA, IgM and IgG in basal diet group, antibiotic group and treat II were measured at the start and the end of the experiment.① The whole experimental period, average daily intake (ADFI) of pigs fed with diet supplemented with 100g/T or 200g/T E. Faecalis was significantly improved compared to those fed with basal diet(P< 0.01). There was no significant difference in ADFI among treat I, treat II and antibiotic group. Average daily gain (ADG) in treat Ⅱ was increased compared with basal diet group (P< 0.05). There was no significant difference of feed to gain ratio(F/G) in any of the groups (P> 0.05). At the stage of 1-14 days, the ADG in different doses of Enterococcus faecalis groups were significantly improved (P< 0.05) and F/G were decreased (P< 0.05) compared to the control group.There was no significant difference (P> 0.05) in ADG and F/G between antibiotic group and Enterococcus faecalis groups. At the stage of 15-28 days, compared with the basal diet group, the ADFI was increased significantly in the group of 200g/T Enterococcus faecalis group (P< 0.05), and there was no significant difference (P> 0.05) between 200g/T Enterococcus faecalis group and antibiotic group.②Throughout the experiment period, compared with the basal diet, diarrhea rate in Treat Ⅰ and Treat Ⅱ was decreased significantly (P< 0.01), and there was no significant difference of diarrhea rate among treat Ⅰ, treat Ⅱ, treat Ⅲ and antibiotic group (P> 0.05). At the stage of 1-14 days, compared with the basal diet group, diarrhea rates of different doses Enterococcus faecalis groups were decreased significantly (P< 0.05),and there was no significant difference between Enterococcus faecalis groups and antibiotic group. At the stage of 15-28 days, there was no significant difference in diarrhea rates between Enterococcus faecalis groups and basal diet group. Diarrhea rates was decreased significantly only in antibiotic group (P< 0.05) compared with the basal diet group, but there was no significant difference between Enterococcus faecalis groups and antibiotic group. ③ There was no significant difference of blood immunity in different groups at the start of trial. At the end of the trial, compared with basal diet group, the level of serum IgG in 200g/T Enterococcus faecalis group was significantly increased (P< 0.05) and the serum IgA levels was tend to be increased (P=0.084). There was no significant difference of serum IgG, IgA, IgM between 200g/T Enterococcus faecalis group and antibiotic group. In conclusion, Nursery piglets fed with diet supplemented with 200g/T E.faecalis could get improved average daily gain, decreased feed to gain and diarrhea rates in the early nursery pigs. Average daily feed intake of experimental pigs was significantly increased at the end of nursery pigs. while diet supplemented with 200g/T E.faecalis could strengthen the body immune system2 Effect of Enterococcus faecalis replacing of dietary antibiotics on the digestibility of feed, intestinal structure of nursery pigsFeed apparent digestibility in basal diet group, antibiotic group and treat II was measured at stage of 1-14 days and 15-28 days. Intestinal development was observed at the end.At the stage of 1-14 days, compared treat II with the basal diet group crude fat and crude protein digestibility was increased by 21.62%(P< 0.05) and 6.62%(P< 0.05) respectively. There was no significant difference between 200g/T Enterococcus faecalis groups and antibiotic group (P> 0.05). At the stage of 15-28 days, the crude protein digestibility in treat II was higher than basal diet group,but there was no significant difference (P> 0.05) in crude fat digestibility. There was no significant difference of crude fiber digestibility in any group at two stages (P> 0.05). The villus height, crypt depth and V/C in treat II at the duodenum, jejunum and ileum had no significant difference (P>0.05) compared with the basal diet group and antibiotic group. The duodenal crypt depth and V/C in treat II decreased by 19.37%(P= 0.051) and increased by 30.12%(P= 0.055) respectively compared with the basal diet group. The villus height in treat Ⅱ was tend to be increaced (P= 0.088) compared with the basal diet group. Therefore, intestinal morphology and nutrient digestibility of nursery pigs were impoved in 200g/T Enterococcus faecalis group.3 Effect of Enterococcus faecalis replacing of dietary antibiotics on the Jejunum and Cecal microbial flora of nursery pigsThe intestinal microbial of basal diet group, antibiotic group and treat Ⅱ was measured at the end of the trial.In the jejunum, copies of E. coli in treat Ⅱ were significantly decreased by 6.98%(P< 0.05) compared with the basal diet group. The number of E. coli has no significant difference (P> 0.05) between treat Ⅱ and antibiotic group. E. coli copies number rbasal diet group> treat Ⅱ> antibiotic group. In the Cecal, there was no significant difference in copies of E. coli among treat Ⅱ, basal diet group and antibiotic group. Obviously, addition of 200g/T Enterococcus faecalis could reduce the number of E. coli in jejunum to maintain the balance of intestinal microflora in nursery pigs.