Effect Of Nisin-producing Lactobacillus(LZS42B) Cultures On Production Performance And Intestinal Microbial Structure And Metabolic Function Of Broilers

Experiment I:Effect of NPLC(bacteriocin-producing Lactobacillus culture)on performance of broilersA total of 360 one-day-old Cobb broiler chickens were randomly divided into 5groups,with 6 replicates in each group and 12 chickens in each replicate.They were fed with I.basal diet(blank control CT);II.basal diet supplemented with 30 mg/kg virginiamycin(positive control VIRG);groups III,IV and V were basal diets supplemented with LZS42B culture containing different bacterial amount of 10~6 cfu/kg(LLN),10~7 cfu/kg(MLN),and 10~8 cfu/kg(HLN).The experiment period was divided into three stages:pre-stage(1-14d),medium-stage(15-28d),and late-stage(29-42d),and the impact of LZS42B on the production performance,blood biochemical index,immune index and slaughter performance of broiler were evaluated.The analyse results showed that,compared with the CT group,the average body weight of broilers in the HLN group increased from 306 g(CT group)to 329 g,increased7.51%at d14,and increased from 2423 g(CT group)to 2538 g,increased 4.74%,at d42(P<0.05).The average daily gain of the HLN group was increased from 18.93 g/d to 20.56g/d,and during the whole experiment period,the average body gain was increased from170.13g/d(CT group)to 178.24g/d(P<0.05).The slaughter rate and carcass net rate of HLN and MLN groups was increased(P<0.05)at d42,while supplemented with 30mg/kg virginiamycin significantly decreased the FCR of the pre-stage and medium-stage(P<0.05).Experiment II:Effect of NPLC on intestinal microbiota and metabolic function of broilersThe bacterial Simpson index and Shannon index was significantly increased in the duodenal of MLN group and HLN group broilers compared with CT group,while was significantly decreased when compared with VIRG group at d14(P<0.05),and no significant effect on alpha diversity of ileal and cecal microbiota.Compared with CT group,diet supplemented with NPLC significantly increased the relative abundance of Unclassified Lactobacillaceae(duodenum or ileum),Lactococcus,Enterococcus in the duodenum,and increased the abundance of Ruminococcus in the cecum(P<0.05),and tended to increases the relative abundance of Unclassified Lachnospiraceae(P=0.063)in the cecum of HLN group at d14.And the virginiamycin significantly increased the relative abundance of Faecallbacterium,Unclassified Lachnospiraceae,and Bacteroides while decreased the relative abundance of Lactobacillus in the cecum at at d28 in the VIRG group(P<0.05).The PICRUSt function prediction of intestinal microbiota showed that high dose of NPLC significantly increased the relative abundance of the glycan biosynthesis and metabolism pathways in the cecal microbiota in the HLN group,and significantly increased the relative abundance of carbohydrate metabolism pathway abundance in ileal microbiota.The experiment results showed that the bacteriocin-producing Lactobacillus culture could improve the performance of broilers by changing the microbiota composition and function of the intestinal microflora.