Tenebrio molitor larvae meal inclusion affects hepatic proteome and apoptosis and/or autophagy of three farmed fish species.

Herein, the effect of dietary inclusion of insect (Tenebrio molitor) meal on hepatic pathways of apoptosis and autophagy in three farmed fish species, gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss), fed diets at 25%, 50% and 60% insect meal inclusion levels respectively, was investigated. Hepatic proteome was examined by liver protein profiles from the three fish species, obtained by two-dimensional gel electrophoresis. Although cellular stress was evident in the three teleost species following insect meal, inclusion by T. molitor, D. labrax and O. mykiss suppressed apoptosis through induction of hepatic autophagy, while in S. aurata both cellular procedures were activated. Protein abundance showed that a total of 30, 81 and 74 spots were altered significantly in seabream, European seabass and rainbow trout, respectively. Insect meal inclusion resulted in individual protein abundance changes, with less number of proteins altered in gilthead seabream compared to European seabass and rainbow trout. This is the first study demonstrating that insect meal in fish diets is causing changes in liver protein abundances. However, a species-specific response both in the above mentioned bioindicators, indicates the need to strategically manage fish meal replacement in fish diets per species.

Physico-chemical and colloidal properties of protein extracted from black soldier fly (Hermetia illucens) larvae.

The black soldier fly larvae (BSFL), Hermetia illucens (Linnaeus), has been largely utilized for animal feed. Due to its interesting composition, BSFL has great potential to be further implemented in the human diet. Herein we compared the flour and protein extract composition based on their moisture, ash, amino acids, mineral, and protein content. To have wide knowledge on protein profile and behavior, SDS-page electrophoresis, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to give information about protein structure and thermal stability, respectively. The flour and protein extract contained respectively 37.3% and 61.1% of protein. DSC graph reported a glass transition temperature around 30 °C, recognizable by a shift in the curve, and an endothermic peak for solid melting at around 200 °C. FTIR analysis showed the main amide bands (A, B, I, II, III) for the flour and protein extract. The foam properties of BSFL protein extract were explored under different temperatures treatment, and the best foam stability was reached at 85 °C with 15 min of treatment. The data highlight the promising techno-functional properties of BSFL protein extract, and that the nutritional composition might be suitable for further use of BSFL as food fortification system.