FUTURE FEED: FEEDING BY-PRODUCTS TO INSECTS AND INSECTS DERIVED PRODUCTS TO ANIMALS

The growing interest in insect-based proteins as sustainable feed ingredients has highlighted the need to better understand the nutritional requirements of insects and the implications of rearing conditions on their composition and subsequent use in animal diets. The present study was conducted with the objective of evaluating the influence of modifications of insect substrates on growth performance, macro- and micro-nutrient profiles, and functional properties of two of the most relevant species used for feed production. The two insects considered were Tenebrio molitor (yellow mealworm, T. molitor) and Hermetia illucens (black soldier fly, H. illucens). The initial phase of the research entailed the execution of a trial on T. molitor, with the objective of investigating the effects of dietary supplementation with specific amino acids and the inclusion of aromatic herbs in the rearing substrate. These trials yielded insights into the regulation of amino acids for insect growth and revealed that high levels of herb inclusion, while having no effect on survival, reduced protein content and modified the antioxidant status of larvae. A parallel experiment was conducted with H. illucens to assess the fortification of circular substrates derived from food by-products with inorganic zinc and selenium. These experiments demonstrated the feasibility of producing biofortified larvae without compromising growth performance. The second part of the research employed in vitro digestion models to evaluate the protein digestibility of insect meals. These tests, conducted on various insect-based matrices, offered a reliable screening method to predict feed value in monogastric nutrition. Furthermore, a systematic bibliographic analysis of in vivo feeding trials across different animal species was conducted. The data were meticulously organized by species, the protein sources were systematically replaced, and the inclusion levels were exhaustively considered. This comprehensive approach yielded a thorough overview of the applicability and limits of insect meal in animal production systems. The findings indicate that both precision-oriented interventions (e.g., amino acid balancing, micronutrient supplementation) and sustainability-driven strategies (e.g., use of agricultural by-products, inclusion of aromatic herbs) can modulate the nutritional profile of insect meals. Collectively, these methodologies augment the prospects of insect meals as functional and sustainable feed ingredients. thus the present thesis demonstrates that rearing substrate modifications can enhance the micronutrient composition and antioxidant capacity of insects. Furthermore, it is evident that insect meals are both digestible and applicable in the context of animal nutrition. Nevertheless, challenges persist regarding production costs and the dearth of long-term safety data on animal health. Addressing these aspects through future research will be essential to fully integrate insect-derived ingredients into sustainable feed chains.