Effective method to control Vibrio mimicus infection in channel catfish Ictalurus punctatus

Abstract

Recently, a skin ulcerative disease caused by Vibrio mimicus has led to heavy economic losses in catfish, including yellow catfish, southern catfish, and Zhengchuan catfish in China. Currently, there was no effective method of controlling the outbreak of this disease. In this study, the bacterial isolates were obtained from dying channel catfish and identified as V. mimicus, which consist of formalininactivated V. mimicus (antigen). After first immunization, four weeks later, fishes were exposed to V. mimicus and the immune response was analyzed: Fish survival, respiratory burst activity of blood leukocytes, serum agglutination titers, and lysozyme activity, every week (during four weeks). Survival was up 90%. Respiratory burst activity of blood leukocytes, serum agglutination titers, and lysozyme activity were determined at 1, 2, 3, and 4 weeks after primary immunization. Immunization of channel catfish protected hosts against V. mimicus infection with a survival percentage of more than 90%. Respiratory burst activity of blood leukocytes was not affected by vaccination. Serum agglutination titer and lysozyme activity were significantly increased after immunization, in comparison with unvaccinated control fish. The obtained results indicated that vaccination is an effective method to control the outbreaks of V. mimicus through regulation of the humoral immune response.

Metabolic Nutrient Preferences ofVibrio mimicus: Leveraging Nucleotides and Oligopeptides from Yellow Catfish for Enhanced Infectivity

“…Lau et al (Lao, 2017) reported an LC50 of 3.17 × 103 CFU/mL when yellow catfish were exposed to V. mimicus. Conversely, Li and Fu (Fu, 2020;Y.-W. Li et al, 2019) reported relatively higher LC50 values of 3.42 × 10 5 CFU/mL and 1.3 × 10 6 CFU/mL for channel catfish and yellow catfish, respectively. Additionally, a separate study found that the LC50 of V. mimicus for grass carp, another bony fish, was 1.076 × 10 7 CFU/mL (Zhang, 2013), significantly surpassing that of Siluriformes.…”