title: Comparison of alternatives to in-feed antimicrobials for the prevention of clinical necrotic enteritis.
abstract: OBJECTIVE
  The capacity for Lactobacillus johnsonii and an organic acid (OA) blend to prevent Clostridium perfringens-induced clinical necrotic enteritis (NE) in chickens was studied.
  
  
  RESULTS
  Cobb 500 birds were allocated into six groups (n = 25 birds/pen, eight pens/treatment); Unchallenged, Challenged, Antimicrobial (zinc bacitracin (ZnB)/monensin), OA, probiotic Lact. johnsonii and probiotic sham (Phosphate-buffered saline). All birds were challenged with Eimeria spp. and Cl. perfringens except for unchallenged controls. Birds fed antimicrobials were protected from NE development as indicated by maintenance of body weight, low mortality and clostridium levels, and decreased intestinal macroscopic lesion scores compared to challenged controls (P < 0.05). Lactobacillus johnsonii-fed birds had reduced lesion scores, whilst OA-fed birds had decreased Cl. perfringens levels. Both Lact. johnsonii and OA-fed birds had improved feed efficiency between days 0 and 28 compared to challenged controls; however, mortality and body weights were not improved by either treatment. Microbial profiling indicated that the challenge procedure significantly altered the jejunal microbiota. The microbiota of antimicrobial-fed birds was significantly different from all other groups.
  
  
  CONCLUSIONS
  Whilst Lact. johnsonii and OA altered specific intestinal parameters, significant protection against NE was not observed.
  
  
  CONCLUSIONS
  Lactobacillus johnsonii and OA did not prevent NE; however, some improvements were evident. Other related treatments, or combinations of these two treatments, may provide greater protection.
authors.affiliation: Pig and Poultry Production Institute, The University of Adelaide, Roseworthy Campus, SA, Australia. Mark.Geier@sa.gov.au
authors.forename: M S
authors.initials: MS
authors.lastname: Geier
authors.forename: L L
authors.initials: LL
authors.lastname: Mikkelsen
authors.forename: V A
authors.initials: VA
authors.lastname: Torok
authors.forename: G E
authors.initials: GE
authors.lastname: Allison
authors.forename: C G
authors.initials: CG
authors.lastname: Olnood
authors.forename: M
authors.initials: M
authors.lastname: Boulianne
authors.forename: R J
authors.initials: RJ
authors.lastname: Hughes
authors.forename: M
authors.initials: M
authors.lastname: Choct
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000382:microbiology*; D003015:Clostridium Infections / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D003016:Clostridium perfringens / Q000302:isolation & purification; D004751:Enteritis / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D007778:Lactobacillus; D008297:Male; D009336:Necrosis / Q000662:veterinary; D011201:Poultry Diseases / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D019936:Probiotics / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents