title: Protective effect of lysozyme-galactomannan or lysozyme-palmitic acid conjugates against Edwardsiella tarda infection in carp, Cyprinus carpio L.
abstract: The protective effect of lysozyme-galactomannan or lysozyme-palmitic acid conjugates orally administered to carp, Cyprinus carpio L. was investigated using a virulent strain of Gram-negative Edwardsiella tarda isolated from an infected fish. Lysozyme-galactomannan conjugate was prepared through controlled Maillard reaction. Lysozyme-palmitic acid conjugate was prepared through base-catalyzed ester exchange using N-hydroxysuccinimide ester of palmitic acid. The conjugates provided substantial protection to carp infected with a Gram-negative bacteria fish pathogen E. tarda NG 8104. Lytic activities of lysozyme conjugates with galactomannan and palmitic acid were about 80 and 71% of native lysozyme using Micrococcus lysodeikticus as a substrate. Feeding with lysozyme conjugates, for 8 days, significantly enhanced fish protection against E. tarda infection. The survival rate was 30% for lysozyme-galactomannan conjugate treated fish and 20% for lysozyme-palmitic acid conjugate treated fish after 6 days cultivation while all control fish died within 3 days. On the other hand, a recovery rate of 40% after 6 days was observed in the fish group that were fed lysozyme-palmitic acid conjugate 3 and 2 h before and after E. tarda challenge, respectively, and for 6 consecutive days. The results of this work show the possibility of utilizing lysozyme conjugates with galactomannan or palmitic acid as a therapeutic for infection in fish.
authors.affiliation: Laboratory of Environmental Science, Ube College, Yamaguchi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Gohya
authors.forename: J N
authors.initials: JN
authors.lastname: Losso
authors.forename: S
authors.initials: S
authors.lastname: Nakai
authors.forename: A
authors.initials: A
authors.lastname: Kato
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D005393:Fish Diseases; D005690:Galactose / Q000031:analogs & derivatives; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control / Q000662:veterinary*; D015416:Maillard Reaction; D008351:Mannans / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009113:Muramidase / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D019308:Palmitic Acid / Q000737:chemistry / Q000494:pharmacology*; D013997:Time Factors; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D008351:Mannans; C012990:galactomannan; D019308:Palmitic Acid; D009113:Muramidase; D005690:Galactose