title: Antibacterial activity of Litsea cubeba (Lauraceae, May Chang) and its effects on the biological response of common carp Cyprinus carpio challenged with Aeromonas hydrophila.
abstract: OBJECTIVE
  The aims of this study were to characterize the antibacterial activity and the chemotype of Litsea cubeba leaf essential oil (EO) harvested in North Vietnam and to investigate the biological effects induced by the leaf powder on growth, nonspecific immunity and survival of common carp (Cyprinus carpio) challenged with Aeromonas hydrophila.
  
  
  RESULTS
  The EO showed the prevalence of linalool (95%, n = 5). It was bactericidal against the majority of tested strains, with minimum inhibitory concentrations ranging from 0·72 to 2·89 mg ml(-1) (Aer. hydrophila, Edwarsiella tarda, Vibrio furnissii, Vibrio parahaemolyticus, Streptococcus garvieae, Escherichia coli, Salmonella Typhimurium). The fish was fed with 0 (control), 2, 4 and 8% leaf powder supplementation diets for 21 days. Nonspecific immunity parameters (lysozyme, haemolytic and bactericidal activities of plasma) were assessed 21 days after feeding period and before the experimental infection. Weight gain, specific growth rate and feed conversion ratio were improved by supplementation of L. cubeba in a dose-related manner, and a significant difference appeared at the highest dose (8%) when compared to the control. The increase in plasma lysozyme was significant for all the treated groups. Haemolysis activity was higher for the groups fed with 4 and 8% plant powder. Antibacterial activity increased significantly for the 8% dose only.
  
  
  CONCLUSIONS
  Litsea cubeba leaf powder increased nonspecific immunity of carps in dose-related manner. After infection with Aer. hydrophila, survivals of fish fed with 4 and 8% L. cubeba doses were significantly higher than those fed with 2% dose and the control.
  
  
  CONCLUSIONS
  A range of 4-8% L. cubeba leaf powder supplementation diet (from specific linalool-rich chemotype) can be used in aquaculture to reduce antibiotic burden and impacts of diseases caused by Aer. hydrophila.
authors.affiliation: Hanoi University of Science and Technology, Hanoi, Vietnam.|UMR Qualisud, CIRAD, Montpellier, France.|UMR Qualisud, CIRAD, Hanoi, Vietnam.
authors.forename: H V
authors.initials: HV
authors.lastname: Nguyen
authors.affiliation: ISEM UMR 226, IRD, Montpellier, France.
authors.forename: D
authors.initials: D
authors.lastname: Caruso
authors.affiliation: UMR Qualisud, CIRAD, Montpellier, France.
authors.forename: M
authors.initials: M
authors.lastname: Lebrun
authors.affiliation: Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: N T
authors.initials: NT
authors.lastname: Nguyen
authors.affiliation: Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: T T
authors.initials: TT
authors.lastname: Trinh
authors.affiliation: UMR Qualisud, CIRAD, Montpellier, France.
authors.forename: J-C
authors.initials: JC
authors.lastname: Meile
authors.affiliation: Hanoi University of Science and Technology, Hanoi, Vietnam.
authors.forename: S
authors.initials: S
authors.lastname: Chu-Ky
authors.affiliation: UMR Qualisud, CIRAD, Montpellier, France.|UMR Qualisud, CIRAD, Hanoi, Vietnam.
authors.forename: S
authors.initials: S
authors.lastname: Sarter
mesh_terms: D016980:Aeromonas hydrophila / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000494:pharmacology; D017756:Aquaculture / Q000379:methods; D002347:Carps; D019587:Dietary Supplements; D005393:Fish Diseases / Q000188:drug therapy* / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D007113:Immunity, Innate; D032862:Litsea / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D009822:Oils, Volatile
keywords: Aeromonas hydrophila; Cyprinus carpio; Litsea cubeba; Vietnam; innate immune response; natural antimicrobials