Fig 1.
Schematic representation of the olive oil supply chain in an environmental perspective and how the black soldier fly (BSF) bioconversion ability that can be seen as an ecosystem service, fits into the chain.
Fig 2.
Relative evolution of the average annual olive production in Portugal mainland by region.
Metadata from the Portuguese Institute of Statistics [22].
Table 1.
Diets prepared using different ratios of OOP and control diet.
Table 2.
Comparison between survival rate, number of prepupae and number of larvae of Hermetia illucens larvae fed on different substitution level of OOP at the end of the trial.
Different letters represent significant differences.
Fig 3.
Growth rate of 6-days old Hermetia illucens larvae fed with different replacement diets over eight days of feeding trials.
Red arrow represents the start of the feeding trial.
Table 3.
Comparison between substrate reduction, feed conversion rate and bioconversion rate of Hermetia illucens larvae fed on different substitution level of olive oil pomace (mean ± SD; n = 5; P<0.05) in wet weight basis.
Different letters represent significant differences.
Table 4.
Comparison between crude protein (CP 4.76 and 6.25) and crude lipid (CL) content of black soldier fly and tested substrates before larvae being introduced with different replacement level of OOP.
Different letters represent significant differences (mean ± SD; n = 5; P<0.05).
Table 5.
Fatty acid profile of Hermetia illucens lipid extracts from four study groups for larvae (L) and tested substrates (S): 0% (control group), 25%, 50%, and 75% replacement of control diet by OOP, expressed as relative abundances (%).
Each value is the mean of five samples ± standard deviation (SD). Mean values of the same row (larvae) with different letters indicate significant differences (p<0.05), n.d. = not determined.
Fig 4.
A- Principal component analysis score plot of larvae fatty acid profile of the four study groups: 0% (control group), 25%, 50%, and 75% replacement of control diet by OOP; B—Heatmap showing the correlation of fatty acids and the four study groups: 0% (control group), 25%, 50%, and 75% replacement of control diet by olive oil pomace.