Effect of a peptide complex on the defense mechanism of shrimp, Marsupenaeus japonicus against pathogens and changes in environmental parameters

Abstract

AbstractThis study examines the effect of a peptide complex extracted from chicken egg yolk on the action of the immune system of kuruma shrimp, Marsupenaeus japonicus, on pathogens as well as changes in environmental parameters. In the design of three independent experiments, we defined the treated shrimp or the control shrimp as shrimp receiving diet with or without peptide complex administration, respectively. In the first experiment, the shrimp were challenged by Vibrio sp. after 1 week of feeding; the results showed that the survival rates of the treated shrimp were 69%. In the other experiments, the shrimp were exposed to low salinity or high temperature to analyze the changes in various immunological parameters. In a low‐salinity test, results showed that the total hemocyte count (THC) of the treated group was significantly higher than that of the control group within 24 hr. In a high‐temperature test, THC and phenoloxidase activity of the shrimp in the treated group displayed significantly higher values than that in the control group during 48 hr. In short, the administration of the peptide complex was significantly effective in the prevention of disease and enhancement of the tolerance of kuruma shrimp to environmental changes.