Dietary effects of housefly (Musca domestica) (Diptera: Muscidae) pupae on the growth performance and the resistance against bacterial pathogen in red sea bream (Pagrus major) (Perciformes: Sparidae)

Insects are attracting increasing worldwide attention as living organisms that produce various useful substances. Although a wide variety of bioactive substances have been identified in insects, there has been little study of the dietary effects of insects that contain these useful substances. In our present study, we describe the dietary effects of housefly [Musca domestica (Linnaeus)] pupae in the red sea bream [Pagrus major (Temminck and Schlegel)]. The addition of low levels of housefly pupae to the diets of these fish caused significant increases in fork length and body weight and produced a marked improvement in feed conversion after 24 days of feeding. Furthermore, the results of 6-month feeding trials revealed that low dietary levels of housefly pupae promote growth performance in the red sea bream. We further found that dietary housefly pupae significantly enhance the peritoneal leukocyte phagocytic activity in the red sea bream and provides increased protection against a lethal challenge from a major pathogen in this species, Edwardsiella tarda (Ewing et al). We also show that housefly pupae dietary supplements do not negatively affect the health of rats [Rattus norvegicus (Berkenhout)]. Our current results indicate the great potential of insects as functional feed sources for farmed fish.