Research Article Dietary Tenebrio molitor Larvae Meal Inclusion Exerts Tissue- Specific Effects on Cellular, Metabolic, and Antioxidant Status in European Sea Bass (Dicentrarchus labrax) and Gilthead Seabream (Sparus aurata) Thomas Bousdras, 1 Konstantinos Feidantsis , 1 Nikolas Panteli , 1 Stavros Chatzifotis , 2 Giovanni Piccolo , 3 Laura Gasco , 4 Francesco Gai , 5 and Efthimia Antonopoulou 1 1 Laboratory of Animal Physiology, Department of Zoology, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece 2 Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Gournes Pediados, P.O. Box 2214, GR-71003, Heraklion, Crete, Greece 3 Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy 4 Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, 10095 Grugliasco, Italy 5 Institute of Sciences of Food Production, National Research Council, Largo Paolo Braccini 2, 10095 Grugliasco, Italy Correspondence should be addressed to Efthimia Antonopoulou; eantono@bio.auth.gr Received 29 March 2022; Accepted 30 September 2022; Published 20 October 2022 Academic Editor: M Xue Copyright © 2022 Thomas Bousdras et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The present study addresses the effects of dietary Tenebrio molitor (TM) larvae meal inclusion on cytoprotective, cell death pathways, antioxidant defence, and intermediate metabolism in the heart, muscle, and digestive tract of gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax). Three experimental diets were formulated to contain 0%, 25%, or 50% inclusion TM levels. Heat Shock Proteins (HSPs) induction was apparent in both species’ muscle at 50% inclusion. Conversely, p44/42 Mitogen-Activated Protein Kinase (MAPK) activation was increased (p <0:05) in both species’ muscle and digestive tract at 25% inclusion. Regarding the apoptotic machinery, TM inclusion exerted no influence on gilthead seabream, while suppression through autophagy may have occurred in the muscle. However, significant apoptosis (p <0:05) was evident in European sea bass muscle and digestive tract. Both fish species’ heart seemed to additionally rely on lipids compared to muscle and digestive tract. In contrast to gilthead seabream, European sea bass exhibited increased (p <0:05) antioxidant activity at 50% TM inclusion. The present findings highlight the dietary derived induction of cellular responses in a species- and tissue-specific manner, whereas European sea bass appears to be more susceptible to TM inclusion. 1. Introduction Fish meal, the basal protein source in compound fish feed, is produced by captured wild fish populations, mainly small pelagic fish [1]. Integration of the aquaculture industry in the sustainable food systems premises potent changes in order to lessen the progressive depletion of wild fish stocks [2–6]. The latter, along with the sharp, increases in fish meal price [1], incentivize the seeking of nutritionally appropriate, and environmentally-sustainable alternatives to fish meal [7–9]. The recent authorization by the EU Commission (EU regulation 2017/893) for the utilization of processed animal protein, derived from seven insects’ species in aquafeeds, reinforced the scientific inquiry regarding the impact of insect meal on fish. Several carnivorous and omnivorous fish species consume insects as a natural nutrient source (reviewed in [10]). In general, insects display a high crude Hindawi Aquaculture Nutrition Volume 2022, Article ID 9858983, 20 pages https://doi.org/10.1155/2022/9858983