Phospholipid supplementation inhibits male and female odor discrimination in mice.

Dietary phospholipids (PLs) are promising supplements that are commonly found as natural food ingredients and emulsifier additives. The present study aimed to evaluate the effect of major PLs found in food supplements on social behavior in mice. In this study, the effect of short-term high dietary PL content was studied in terms of social odor discrimination and social interactions with male and female intruders in male mice. We used odor discrimination and habituation tests to demonstrate that PL-fed male mice tend to lose preference toward female odor and fail to discriminate against socially significant scents. At the same time, test animals recognize non-social odors. We also found that PL affected the social behavior of the test males, who tend to behave indiscriminately toward male and female intruders during direct contact. Brain metabolomic profiling revealed no major changes in the intermediary metabolism or neurotransmitter biosynthesis. At the same time, intranasal PL application resembled the effects of dietary supplementation. These data suggest that certain PL might suppress pheromone perception in the olfactory system and affect the sense of socially important odor cues.

Influence of Bacillus thuringiensis and avermectins on gut physiology and microbiota in Colorado potato beetle: Impact of enterobacteria on susceptibility to insecticides.

Gut physiology and the bacterial community play crucial roles in insect susceptibility to infections and insecticides. Interactions among Colorado potato beetle Leptinotarsa decemlineata (Say), its bacterial associates, pathogens and xenobiotics have been insufficiently studied. In this paper, we present our study of the survival, midgut histopathology, activity of digestive enzymes and bacterial communities of L. decemlineata larvae under the influence of Bacillus thuringiensis var. tenebrionis (morrissoni) (Bt), a natural complex of avermectins and a combination of both agents. Moreover, we estimated the impact of culturable enterobacteria on the susceptibility of the larvae to Bt and avermectins. An additive effect between Bt and avermectins was established regarding the mortality of the larvae. Both agents led to the destruction of midgut tissues, a decrease in the activity of alpha-amylases and alkaline proteinases, a decrease in the Spiroplasma leptinotarsae relative abundance and a strong elevation of Enterobacteriaceae abundance in the midgut. Moreover, an elevation of the enterobacterial CFU count was observed under the influence of Bt and avermectins, and the greatest enhancement was observed after combined treatment. Insects pretreated with antibiotics were less susceptible to Bt and avermectins, but reintroduction of the predominant enterobacteria Enterobacter ludwigii, Citrobacter freundii and Serratia marcescens increased susceptibility to both agents. We suggest that enterobacteria play an important role in the acceleration of Bt infection and avermectin toxicoses in L. decemlineata and that the additive effect between Bt and avermectin may be mediated by alterations in the bacterial community.