Evaluation of Apple Pomace as a Circular Feed Ingredient for Tenebrio molitor Larvae

Worldwide production of apple juice results in several million tons of apple pomace (AP) produced as a byproduct. The objective of this study was to determine whether the incorporation of AP into the diet of mealworm larvae (Tenebrio molitor) would influence growth performance, survival, and nutritional composition relative to standard feed. After 4 weeks of ad libitum access to commercial mealworm feed and non-nutritive water-storing beads (WB) or AP, no significant differences in weight gain or overall survival were measured. In both cohorts, higher pupation rates were associated with greater mortality among the remaining larvae; however, the weekly probability of survival was better in the AP cohort, potentially due to antioxidants present in apples. When measured on a dry matter basis, protein (34.4 vs. 33.8%), fat (51.9 vs. 52.2%), and ash (0.20 vs. 0.16%) levels did not differ significantly between the WB and AP cohorts, respectively. However, the WB cohort had more moisture (66.9 vs. 63.9%) likely because water beads provide a more direct source of hydration. These findings show that apple pomace, traditionally viewed as a waste product, shows promise in industrial applications.