The Use of Defatted Tenebrio molitor Larvae Meal as a Main Protein Source Is Supported in European Sea Bass (Dicentrarchus labrax) by Data on Growth Performance, Lipid Metabolism, and Flesh Quality

Ana Basto; Josep Calduch-Giner; Beatriz Oliveira; Lisa Petit; Tiago Sá; Margarida R G Maia; Susana C Fonseca; Elisabete Matos; Jaume Pérez-Sánchez; Luisa M P Valente

doi:10.3389/fphys.2021.659567

The Use of Defatted Tenebrio molitor Larvae Meal as a Main Protein Source Is Supported in European Sea Bass (Dicentrarchus labrax) by Data on Growth Performance, Lipid Metabolism, and Flesh Quality

Front Physiol. 2021 Apr 15:12:659567. doi: 10.3389/fphys.2021.659567. eCollection 2021.

Authors

Ana Basto^{1

2}, Josep Calduch-Giner³, Beatriz Oliveira^{1

2}, Lisa Petit², Tiago Sá^{1

2}, Margarida R G Maia¹, Susana C Fonseca⁴, Elisabete Matos⁵, Jaume Pérez-Sánchez³, Luisa M P Valente^{1

2}

Affiliations

¹ ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.
² CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Matosinhos, Portugal.
³ IATS - CSIC, Instituto de Acuicultura Torre de la Sal, Castellón de la Plana, Spain.
⁴ GreenUPorto, DGAOT, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.
⁵ SORGAL - Sociedade de Óleos e Rações, S.A., S. João de Ovar, Portugal.

Abstract

Objective: This study aims to determine the maximal inclusion level of defatted (d-) Tenebrio molitor larvae meal (TM) able to replace dietary fishmeal (FM) without compromising growth performance, general metabolism, and flesh quality traits in European sea bass, and to evaluate the major underlying physiological mechanisms.

Materials and methods: Fish (55 ± 2 g) were fed with diets containing increasing levels of dTM: 0, 40, 80 and 100% (CTRL, TM40, TM80, and TM100, respectively) to replace FM. After 10 weeks of feeding, the growth performance, nutrient and energy balance, intestinal integrity, plasma metabolites and the expression of genes related to growth and nutrient metabolism, in liver and muscle were determined. The fatty acids (FA) profile, textural properties and color were also evaluated in muscle.

Results: Protein and lipids digestibility remained unaltered up to 80% dTM inclusion. Growth performance parameters were similar among dietary treatments. The dTM inclusion increased the hepatosomatic index in fish fed TM100. Muscle eicosapentaenoic acid, docosahexaenoic acid and n-3 long-chain polyunsaturated FA levels were maintained up to 80% dTM inclusion, but total cholesterol and non-esterified FA increased with dietary dTM inclusion. In liver, the expression of elongation of very long-chain FA protein 6 (elovl6) and FA desaturase 2 (fads2) did not change in fish fed TM40 and TM80, but elovl6 decreased whilst fads2 increased in fish fed TM100 when compared to those fed CTRL. The expression of cholesterol 7 alpha-monooxygenase (cyp7a1) decreased with dietary dTM inclusion. In muscle, the expression of myoblast determination protein-2 (myod2) decreased in fish fed TM80 and TM100.

Conclusion: It is feasible to substitute dietary FM by dTM up to 80% in European sea bass without detrimental effects on nutrient digestibility, growth performance and associated genetic pathways, whilst assuring fillet nutritional value for human consumption.

Keywords: alternative protein sources; fatty acids profile; feedstuffs; insect meal; muscle cell proliferation and differentiation; nutrient utilization.