Insects in Rainbow Trout (Oncorhynchus Mykiss) Feed: Effect on Growth, Fatty Acid Composition and Sensory Attributes

Abstract

Background. An ongoing quest for alternative feed sources in global aquaculture includes insect breeding for feed and food production. The aim of this study was to evaluate the effect of partial to full replacement of commercial diets with live insects on growth and health parameters of rainbow trout, as well as on sensory and texture attributes and fatty acid composition of fish muscle. Material and methods. Five isocaloric diets containing commercial pellets and live insects were evaluated in rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), in a 60-day feeding trial. Control Group (K) was fed commercial pellets only. In other groups, 25% gross energy of pellets was replaced by live adult house cricket, Acheta domestica (Group C), live superworm, Zophobas morio larvae (Group L), or a combination of 12.5% crude energy of each (group LC). The insect-only group (I) was fed live cricket and superworm only (50% by 50% crude energy). Results. No significant differences were found in growth, survival, feed conversion ratio (dry basis), or energy utilization between groups. The protein efficiency ratio was highest in Group K and decreased with increasing cricket proportion. Insect inclusion was associated with lower content of nutritionally valuable n-3 fatty acid in fish muscle. Subjective sensory evaluation of cooked fillets revealed significantly less acceptable taste, aroma, and aftertaste in Group I than for Groups K, L, and LC. Some differences were found in the whiteness and redness of fillets between groups. The control group had significantly lower hardness compared to those receiving insect diets. No gross morphological or histopathological anomalies of viscera in any group and no significant differences in 7-ethoxyresorufin-O-deethylase activity were observed. Conclusions. Live insects replaced the commercial diet of the equivalent caloric level without negative effects on the growth or health of rainbow trout. The lower content of n-3 fatty acids and differences in color and texture of fillets from fish fed insects may influence acceptability to consumers. The high cost of insects compared to commercial feed currently limits their widespread use in trout production.

Recent advances in the utilization of insects as an ingredient in aquafeeds: A review

“…Feeding high levels of BSF larvae meal to rainbow trout (40% inclusion level; Renna et al., 2017 ; Mancini et al., 2018 ; Secci et al., 2019 ) or Jian carp (14% inclusion level; Zhou et al., 2018 ) has been shown to decrease both n-3 and n-6 PUFA but increase the SFA content. Similar findings were observed in rainbow trout ( O. mykiss ) fed live adult house cricket Acheta domestica or live superworm Z. morio larva (at 25% and 100% of gross energy, single or in combination); EPA and DHA content in muscle of fish fed insects was 45% and 63% of the control fish, respectively ( Turek et al., 2020 ). Similarly, there was a reduction in the n-3/n-6 ratio and the relative content of EPA and DHA (% total fatty acids) in the muscle of European seabass fed defatted TM larvae meal that replaced fish meal at increasing levels (0%, 50%, and 100%), however, the absolute value of EPA + DHA in a fillet portion of 100 g for human consumption remained above the recommended level for human consumption (>0.25 g/100 g of wet weight) in all fish and did not vary significantly among treatments ( Sousa, 2020 ).…”

“…Nowadays, insects are viewed as the most promising and sustainable source of animal protein mainly because of their nutritional value, amino acid composition and ease of propagation ( Iaconisi et al, 2019 ; Gasco et al., 2016 , 2020 ; Biancarosa et al., 2019 ; Tilami et al., 2020 ; Were et al., 2021 ). Many of these insects have shown beneficial conversion factors and productivity, fast life cycles and the ability to grow on a variety of available substrates, yielding high quality and readily assimilated proteins and highly unsaturated fatty acids (HUFA), as well as vitamins and functional compounds ( Tacon and Metian, 2008 ; Gasco et al., 2016 ; Turek et al., 2020 ; Shafique et al., 2021 ). Consequently, some have been incorporated into aquafeed formulations for different aquatic species, yielding interesting results.…”

Insect Fat in Animal Nutrition – A Review

“…Figure 1. Fatty acid profiles of insect lipids and commonly used fats and oils (% of total FAs) (Finke, 2002;Pereira et al, 2003;Tomotake et al, 2010;Mentang et al, 2011;Oonincx et al, 2012;Siemianowska et al, 2013;Barroso et al, 2014;Alves et al, 2016;Li et al, 2016;Adámková et al, 2016;2017;Dreassi et al, 2017;Francardi et al, 2017;Iaconisi et al, 2017;Schiavone et al, 2017;Dalle Zotte et al, 2018;Megido et al, 2018;Turek et al, 2018;Alifian et al, 2019;Benzertiha et al, 2019;Chieco et al, 2019;Gasco et al, 2019a;Mlcek et al, 2019;Kierończyk et al, 2018;Kim et al, 2020;Ruschioni et al, (Sosa and Fogliano, 2017). Several studies have already studied the supplementation of insect oils in broiler chicken, turkey, and Japanese quail diets, demonstrating total or partial replacement of commonly used fat and oil sources (Cullere et al, 2016;Cullere et al, 2017;Schiavone et al, 2017;Kierończyk et al, 2018Benzertiha et al, 2019;Kierończyk et al, 2020;Kim et al, 2020;Sypniewski et al, 2020).…”

Understanding Nutrition and Metabolism of Threatened, Data-Poor Rheophilic Fishes in Context of Riverine Stocking Success- Barbel as a Model for Major European Drainages?

“…Lately, with the advent of ‘off-season breeding’, there has been some opportunity in overcoming some of these issues [ 14 ]. However, their captive feeding is mostly on second priority, hit-and-trial basis, often leading to morphological alterations and nutritional deficiencies [ 15 , 16 , 17 , 18 ]. They may cascade to undetected causal mortalities after release which is easy to be blamed on problems existing in the habitat or release site.…”

“…On the other hand, longer time spent in captivity and resulting behavioral deficits might impair survivability too [ 8 , 14 ]. A lack of acclimation or conditioning procedures might occur before release, (i.e., in-situ pen or cage-based rearing, pond rearing with natural food, adding complexities within hatchery rearing tanks, training to live feed, exposure to predators, and smell of injured conspecifics) [ 7 , 8 , 14 , 15 , 16 ]. Several studies confirm the ‘bigger is better’ hypothesis in the context of post-stocking chances of survivability (discussed later).…”