Fig. 9

Impact of different treatment groups on the metabolic profile of housefly larvae. a Principal component analysis plots of the metabolite composition of samples from different treatment group. Each symbol represents a sample, with different symbol shapes denoting different groups. The circular line indicates the 95% confidence interval. b Metabolite changes between different treatment groups. Fold change of A versus B is calculated as A/B, ‘up’ represents VIP > 1, FC > 1.5, P < 0.05, ‘down’ represents VIP > 1, FC < 0.667, P < 0.05. Volcano plot for the expression pattern of each metabolite. Red and blue points represent upregulated metabolites and downregulated metabolites, respectively. The discriminatory metabolites were identified and ranked according to the extent of the difference by comparing the BB group versus the LB group (c), the BBP group versus the LB group (d), the HB group versus the LB group (e) and the HBP group versus the LB group (F). Green and red circles denote BB, BBP, HB or HBP downregulated and BB, BBP, HB or HBP upregulated metabolites, respectively. BB, Beneficial bacteria cocktail; BBP, beneficial bacteria phage cocktail; FC, fold change; HB, harmful bacteria cocktail; HBP, harmful bacteria phage cocktail; LB, Luria-Bertani (negative control) VIP, variable importance in projection