Utilization of Agro-Industrial Residues in the Rearing and Nutritional Enrichment of Zophobas atratus Larvae: New Food Raw Materials.

Edible insects are a potential alternative food source of high feed conversion efficiency and protein content. Zophobas atratus is an edible insect that adapts to different diets, enabling sustainable rearing by adding value to by-products and agro-industrial residues. This study aimed to evaluate the performance and nutritional characterization of Zophobas atratus larvae fed with different proportions of grape residue. Physicochemical analysis of the diets and larvae (AOAC procedures), fatty acid profile (chromatographic techniques), metals and non-metals (inductively coupled plasma optical emission spectrometry), larval mass gain, feed conversion efficiency, and mortality rate were assessed. The replacement of 25% of the conventional diet with grape residue increased lipid, ash, and fiber contents and reduced protein, carbohydrates, and energy. It promoted greater mass gain, lower mortality rate, and reduced larval growth time by 51%. Among the replacements, 25% resulted in the second-highest content of calcium, sodium, magnesium, and zinc, and the lowest content of potassium and phosphorus in the larvae. The 100% replacement resulted in the highest amounts of C18:2n6 (27.8%), C18:3n3 (2.2%), and PUFA (30.0%). Replacing 25% of the conventional diet with grape residue is equivalent to the conventional diet in many aspects and improves several larvae performance indices and nutritional values.

Rhodotorula sp. and Trichosporon sp. are more Virulent After a Mixed Biofilm.

Rhodotorula spp. and Trichosporon spp. are opportunistic pathogens, and although an association between these two species in the same infection appears to be uncommon, it has been reported. This is the first study that aimed to evaluate the pathogenesis of a co-infection by R. mucilaginosa and T. asahii, using a new in vivo model, the Zophobas morio larvae. Suspensions from planktonic and biofilm-recovered cells were injected in the larvae as in monospecies as mixed (a ratio of 1:1 for both agents of a of 105 inoculum). Individual and mixed biofilms of R. mucilaginosa and T. asahii were produced for 24 and 48 h, and they were partially characterized by crystal violet and reduction of tetrazolium salt. When evaluating the impact of the planktonic suspension in vivo we verified that the fungi in monoculture were more able to kill the larvae than those from planktonic mixed suspension. On the other hand, regarding biofilm-recovered cells, there was an increase in the death of larvae infected for mixed suspensions. Moreover, the death rate was more pronounced when the larvae were infected with 48 h biofilm-recovered cells than the 24 h ones. T. asahii was the best producer of total biomass, mainly in 48 h. The metabolic activity for both yeasts organized in biofilm maintained the same pattern between 24 and 48 h. The present study proves a synergistic interaction between R. mucilaginosa and T. asahii after an experience in a mixed biofilm. Our results suggest that both species were benefited from this interaction, acquiring a greater potential for virulence after passing through the biofilm and this ability was acquired by the cells released from the biofilm.