How Does Pikeperch Sander lucioperca Respond to Dietary Insect Meal Hermetia illucens? Investigation on Gut Microbiota, Histomorphology, and Antioxidant Biomarkers

Hung Quang Tran,Francesco Gai,Mahyar Zare,Tatyana Gebauer,Markéta Prokešová,Elena Colombino,Laura Gasco,Antonia Concetta Elia,Ilario Ferrocino,Christian Caimi,Vlastimil Stejskal

doi:10.3389/fmars.2021.680942

Abstract

Effects of feeding dietary defatted black soldier fly (Hermetia illucens) larvae meal (HI) on intestine microbiota, and on histomorphology, oxidative enzyme activities in liver and intestine of pikeperch (Sander lucioperca) were investigated. Four isoproteic (45% crude protein) and isolipidic (18% ether extract) diets were formulated to include 0% (CO), 9% (HI9), 18% (HI18) and 36% (HI36) of HI as replacement for fishmeal at 0, 25, 50, and 100%, respectively, and were fed to triplicate groups of juvenile pikeperch (initial body weight, 68.7 ± 7.1 g) for 84 days. No adverse effects were detected on the intestine of pikeperch fed diet groups, in terms of histomorphology (P &gt; 0.05), while fish fed free or low levels of HI (≤ 9% in diet) showed significant liver degeneration (P &lt; 0.05). Dietary HI significantly affected the oxidative enzyme activities of catalase and glutathione peroxidase in the liver, and glutathione S-transferase in the intestine (P &lt; 0.05), while activity of superoxide dismutase in both liver and intestine was HI-dose independent (P &gt; 0.05). Feeding HI-containing diets positively modulated the richness and diversity of intestinal microbiota, especially for HI18 group (P &lt; 0.05). Inclusion HI up to 18% (50% fishmeal replacement) in pikeperch diets increased abundance of Clostridium, Oceanobacillus, Bacteroides, and Faecalibacterium genera, whereas the predominant bacterium, Cetobacterium was found in control and HI36 groups. This study reveals the potential of HI as an immune and health booster for juvenile pikeperch.

Highlights

Aquaculture is the largest global consumer of fishmeal production, accounting for 68–73% (Shepherd and Jackson, 2013; Tacon and Metian, 2015)
This study indicates that in liver of pikeperch dietary HI did not alter the superoxide dismutase (SOD), CAT, or Glutathione S-transferase (GST) oxidative enzymes, while significantly reduced SeGPx activity, a result that is in agreement with those of previous study (Elia et al, 2018), who performed a trial on rainbow trout fed dietary HI
Tocher et al (2002) reported that a high dietary polyunsaturated FAs (PUFA) content increased lipid peroxidation in fish tissues, and the SeGPx enzyme activity involved in reducing peroxides, including

Summary

Introduction

Aquaculture is the largest global consumer of fishmeal production, accounting for 68–73% (Shepherd and Jackson, 2013; Tacon and Metian, 2015). The expansion and intensification of the production of terrestrial crops will lead to tremendous environmental burdens pertaining to climate change, biodiversity loss, and increasing demand for arable land and water. Among such burdens, land use is considered the one that entails the greatest pressures on the planet (Foley et al, 2005, 2011; Boissy et al, 2011). The use of seven insect species (two flies, two mealworms, and three cricket species) in fish diets has been authorised by the European Commission (Regulation No 2017/893) Among these species, black soldier fly (Hemertia illucens), which belongs to the Diptera order, has received the most research interest (Hua, 2021). H. illucens meal-containing diets have shown lower environmental impacts associated with abiotic depletion, acidification potential, eutrophication potential, climate change, human toxicity potential, and marine aquatic ecotoxicity potential for Arctic char (Salvelinus alpinus) (Smárason et al, 2017) and lower water use for European perch (Perca fluviatilis) (Stejskal et al, 2020) than insectfree diets

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