Towards Functional Insect Feeds: Agri-Food By-Products Enriched with Post-Distillation Residues of Medicinal Aromatic Plants in Tenebrio molitor (Coleoptera: Tenebrionidae) Breeding

Abstract

Sustainability, circular economy and alternative production systems are urgent imperatives for humanity and animal husbandry. Unless wasted, agri-food by-products can offer a promising source of high value. We evaluated the effect of rice bran (RB), corncob (CC), potato peels (PP), solid biogas residues (BR), and olive-oil processing residuals (OR), as alternative substrates to wheat bran (WB as control), on the growth and nutritional value of Tenebrio molitor during its breeding for animal feeds and/or human consumption. Innovation-wise, we further investigated the substrate supplementation (0, 10, 20%) with post-distillation residues of Mediterranean aromatic-medicinal plants (MAPs: lavender, Greek oregano, rosemary, olive; 1:1:1:1 ratio). Tenebrio molitor larvae (TML) were reared in all the studied substrates, and TML and diets’ proximate and fatty acid compositions as well as total phenol and flavonoid content and antioxidant potential were assessed using standard procedures. After statistical analysis of correlations, we observed that CC promoted oviposition and progeny survival; larval weight and dry matter were positively affected mainly by dietary energy and fat content; number of TML and/or larval weight increased using 10% MAPs inclusion in WB, RB and OR or RB, OR, BR and PP, respectively, which did not affect protein content; TML fatty acid composition decreased the content of saturated ones and increased that of mono-unsaturated ones; MAPs residues had an apparent favorable impact on total phenolic content and antioxidant activity of each substrate, with RB displaying the highest capacity and content. These findings indicate that alternative substrates can be exploited and their enrichment with natural phenolics is able to influence T. molitor growth, offering highly beneficial and nutritional value.

Carob (Ceratonia siliqua) as Functional Feed Is Beneficial in Yellow Mealworm (Tenebrio molitor) Rearing: Evidence from Growth, Antioxidant Status and Cellular Responses

“…Simultaneously, insects’ mass production can fit well with the circular economy model, which embraces the continual and efficient recycling and reuse of materials, by-products or wastes as resources in an effort to minimize waste generation [ 10 ]. Insects’ production may exploit several low-value organic, industrial and agricultural by-products as rearing substrates which insects can efficiently be recycled and bioconverted into high-value protein [ 8 , 11 , 12 ]. In particular, recent studies demonstrated that by-product substrates may increase the final weight and enhance the antioxidant capacity of insects [ 11 , 13 ].…”

“…Insects’ production may exploit several low-value organic, industrial and agricultural by-products as rearing substrates which insects can efficiently be recycled and bioconverted into high-value protein [ 8 , 11 , 12 ]. In particular, recent studies demonstrated that by-product substrates may increase the final weight and enhance the antioxidant capacity of insects [ 11 , 13 ].…”

“…However, extensive insect meal inclusion may cause imbalance in the gut microbiota [ 17 ] and concomitant stress may induce autophagy in the liver of sea bream [ 18 ]. The inclusion of medicinal and aromatic plants in the rearing of Tenebrio molitor larvae has been shown to benefit their growth performance, resulting in higher survival and total larval weight, and improvement of the fatty acid profile of the larvae [ 11 ]. In addition, the substrate enrichment with phenolics from medicinal and aromatic plants may not only enhance the growth performance but can also increase the antioxidant capacity of the larvae [ 11 ].…”

Growth performance and meat quality traits of Pekin ducks fed with different amounts of pelleted Ptecticus tenebrifer

“…This finding can offer a convincing point for consumers to accept the use of insect‐based feed in duck diets, as shown previously, as the inclusion of insect‐based feeds can result in meat with higher levels of phenols, flavonoids, essential oils, and antioxidants compared with their control groups (Andreadis et al . 2022; Van Huis 2022). Moreover, the breast meat color values of ducks were not affected ( p > 0.05) by increasing levels of pelleted PT, except for lightness (L* values) on day 7 and yellowness (b* values) on day 3 ( p < 0.05).…”

Edible insects: Challenges and prospects

“…When residues of medical aromatic plants (lavender, Greek oregano, rosemary, olive) were supplemented to rice bran and corn cob as substrates to feed yellow mealworm, its growth and antioxidant activity increased (Andreadis et al . 2022).…”