Review: Insects and former foodstuffs for upgrading food waste biomasses/streams to feed ingredients for farm animals

Insight into the chemical and nutritional fat profile of Tenebrio molitor larvae reared on different Agri-food by-products

Insects are capable of feeding with a variety of substrates, being possible obtaining products rich in protein using by-products from agri-food industry. Hence, the aim of this work was evaluating the effect of different diets based on three agri-food industry by-products of Tenebrio molitor larvae's total fat contents and fatty acid profiles. Stabilized Alperujo (ALP), Pleorotus ostreatus spent substrate (POS) and olive leaf flour (OLF) were used mixed with wheat bran, control diet, at different percentages (20-100 %). All substrates studied modified the parameter analysed respect to the control diet. OLF subtract led to the greatest effects on the total fat content at percentage higher than 40 %. Respect to fatty acid profile, the most relevant changes were the increases of total MUFA content in samples from all T. molitor larvae fed with ALP and in most of those fed with POS, due to the specific increases of oleic acid content. On the contrary, total PUFA content decreased in most cases except for OLF substrate when the addition percentages were lower than 100 %. Moreover, OLF substrate enhanced the presence of ω-3. Finally, according to European regulations on nutritional claims, this fat fraction could be labelled as "source of ω-3", "high in monounsaturated fat" and "high in unsaturated fats". We can therefore conclude that feeding T. molitor with these agri-food by-products, especially from olive oil industry, enhanced the fatty acids profile of their fat fraction.

Former Food and Agro-Industrial By-Products in Dairy Cow Diets: Effects on Milk Quality and Cheese Production

The use of former foodstuff and by-products in cow diets could improve the environmental sustainability of livestock. However, knowledge about the effects of these feeds in ruminant diets on the quality of dairy products is lacking. This study investigated the effects of integrating wheat distillers' grain with solubles (WDGS) and a former foodstuff product (FFP) into the diet of dairy cows on milk and cheese quality. The environmental impact of the two feeding systems has been evaluated by LCA. A double crossover design was set up with 84 Holstein cows, alternating a control diet and a circular one. In the circular diet, traditional feeds were partially replaced with 4 kg/d WDGS and 3 kg/d FFP. The results showed no effects on dry matter intake and milk yield, while fiber digestibility improved. A reduction in the milk fat content and a modification of the fatty acid profile of milk and cheese were observed. Conversely, cheese yield, composition, and sensory attributes were not affected. The environmental impact of the diet was significantly reduced in terms of land occupation, net fresh water, and global warming potential. These findings suggest that these feeds can be safely included in dairy cow diets. This approach could significantly contribute to reducing greenhouse gas emissions, enhancing the sustainability of the dairy system.

Food waste used as a resource can reduce climate and resource burdens in agrifood systems

Global food loss and waste continues to increase despite efforts to reduce it. Food waste causes a disproportionally large carbon footprint and resource burdens, which require urgent action to transition away from a disposal-dominated linear system to a circular bioeconomy of recovery and reuse of valuable resources. Here, using data from field-based studies conducted under diverse conditions worldwide, we found collective evidence that composting, anaerobic digestion and repurposing food waste to animal feed (re-feed) result in emission reductions of about 1 tCO2e t-1 food waste recycled compared with landfill disposal. Emission mitigation capacity resulting from no landfill disposal in the United States, the European Union and China would average 39, 20 and 115 MtCO2e, which could offset 10%, 5% and 17% of the emissions from these large agricultural systems, respectively. In addition, re-feed could spare enormous amounts of land, water, agricultural fuel and fertilizer use. Our findings provide a benchmark for countries developing food waste management strategies for a circular agrifood system.

Black soldier fly (Diptera: Stratiomyidae) larvae reduce cyathostomin (Nematoda: Strongylidae) eggs but develop poorly on horse manure

Cyathostomins are common digestive tract parasites of grazing horses that spread through contact with horse feces. Horse feces are colonized by a variety of organisms, some of which could serve to reduce parasite loads in horse pastures. Black soldier fly (Hermetia illucens L.; Diptera: Stratiomyidae) larvae (BSFL) could be an ideal candidate for biological control of cyathostomins, due to their near-global distribution, low risk of pathogen transmission, ability to develop on a variety of nutrient-poor substrates (including horse manure), and dramatic effect on microbial communities that cyathostomins depend on. Here, using controlled feeding bioassays, we evaluated the effect of BSFL on cyathostomin egg densities in horse manure while also tracking BSFL performance on manure relative to standard grain-based diets. We found that BSFL consumed less substrate, were slower to reach the prepupal stage, and ultimately yielded less biomass when reared on horse manure compared to grain-based diets. However, BSFL reduced average cyathostomin egg densities in horse manure by over 3-fold. Overall, our results suggest that despite horse manure being a poor substrate for BSFL growth, BSFL effectively reduce cyathostomin egg loads in infected horse manure, though the mechanisms by which they do this are uncertain. While BSFL are known to transform the microbial communities within a diversity of rearing substrates, their effect on larger, parasitic organisms in animal manures may be underappreciated. Promoting the decomposition of infected horse manure with BSFL might be a promising approach to managing parasite populations among grazing horses.

Framework for valorizing waste- and by-products through insects and their microbiomes for food and feed

One third of the food produced for human consumption is currently lost or wasted. Insects have a high potential for converting organic waste- and by-products into food and feed for a growing human population due to symbiosis with microorganisms. These symbioses provide an untapped reservoir of functional microbiomes that can be used to improve industrial insect production but are poorly studied in most insect species. Here we review the most current understanding and challenges of valorizing organic waste- and by-products through insects and their microbiomes for food and feed, and emerging novel food technologies that can be used to investigate and manipulate host(insects)-microbiome interactions. We further construct a holistic framework, by integration of novel food technologies including holo-omics, genome editing, breeding, phage therapy, and administration of prebiotics and probiotics to investigate and manipulate host(insects)-microbiome interactions, and solutions for achieving stakeholder acceptance of novel food technologies for a sustainable food production.

Fatty Acid Profile and Thermal Behavior of Fat-Rich Edible Insect Oils Compared to Commonly Consumed Animal and Plant Oils

This study compared the physicochemical properties of edible insect oils from silkworm (Bombyx mori) pupa (SP), sago palm weevil (Rhynchophorus ferrugineus) larva (PW), and bamboo caterpillar (Omphisa fuscidentalis; BC) to oils from chicken skin (CK), beef back fat (BF), pork back fat (PF), salmon belly (SB), sea bass belly (BB), coconut (C), and peanut (P). The fatty acid profiles and thermal behaviors (crystallization and melting) of the extracted oils were evaluated. PW and BC oils had more saturated fatty acids (SFAs) than CK, PF, SB, BB, and P oils. SP oil had equivalent SFA content to CK and BB oils. Insect oils exhibited similar monounsaturated fatty acid concentrations in all samples, except C oils. PW and BC oils exhibited a higher content of palmitoleic acid than the other oils. SP oils contained polyunsaturated fatty acids similar to those in SB and BB oils, which were higher than those in PW, BC, CK, BF, and PF oils. SP oil also exhibited the highest concentration of α-linolenic acid (C18:3 n-3). Arachidonic acid (0.01-0.02 g/100 g) in all insect oils was lower level compared to CK, BF, PF, SB, and BB oils. SP oil (0.03 g/100 g) exhibited a slightly higher level of eicosapentaenoic acid compared to PW (0.01 g/100 g) and BC (0.01 g/100 g) oils. The insect oils were liquid at ambient temperature, solid below -15°C, and required less energy (△Hm-max) for melting than other samples. This study indicated that insects, particularly SP, could serve as an alternative source of fat to meet its growing demand.

Influence of age, gender, and willingness to adopt former foodstuffs on the perception of Italian farm animal veterinarians

Background

Veterinarians play an essential role in improving animal care, as they are often viewed as trusted advisors, particularly in relation to disease control and management; however, little is known about veterinarians' perceptions and attitudes toward alternative feeds. The aim of this study was to investigate the influence of age, gender, and willingness to adopt on the attitudes of livestock veterinarians toward the use of alternative feeds in farm animals.

Methods

A total of 136 active veterinarians completed the online survey, distributed through the main veterinary associations in Italy. The questionnaire contained items on dietary recommendation, awareness, benefit and safety perceptions, and a willingness to adopt former foodstuffs (FFs), complemented with socio-demographic questions.

Results

Almost 90% of the population reported a willingness to adopt FFs as feed. Men and women did not share the same perceptions of the nutritional composition of FFs, while the importance of product availability was found to be a key factor driving the age difference. Participants willing to adopt FFs as feed linked positive attitudes to attributes such as digestibility, energy intake, and positive social implications.

Conclusion

Our findings provide a basic background on the current use of the FFs in Italy and suggest the need for the development of educational programs and marketing strategies to enhance the acceptability of FFs in farm animals to ultimately promote the transition toward more sustainable animal production. This study has limitations, including the number of recorded responses and reliance on national estimates. Future research is needed to investigate the perceptions of farmers and animal nutritionist from different countries. This could provide a more detailed picture of the current situation in Europe about the potential of using FFs in farm animals' feed, thus further contributing toward a greener and safer livestock production sector.

Former foodstuffs in feed: a minireview of recent findings

The sustainability of all productive activities, including livestock farming, becomes a fundamental challenge in the current scenario. Livestock production faces both old and new challenges related to climate change, food safety, and feed-food competition. The latter aspect has recently become a hot topic, and many researchers are turning their attention to this issue. According to circular economy principles, former foodstuffs have characteristics that make them a promising source of raw material for animal feed. The main objective of the present review is to provide a brief overview of the most recent studies (published between 2016 and 2022) addressing the dietary inclusion of former foodstuffs for livestock. The articles analyzed cover key findings from both in vitro and in vivo studies of former foodstuffs included in the diets for pigs, cows, and broilers, and assess the associated safety aspects. The articles provide information on livestock performances and product quality, as well as feed digestibility, fecal microbiota, and blood analysis. Although the evidence supports the inclusion of former foodstuffs in livestock diets as a safe, effective, and sustainable ingredient, this analysis of the most recent literature also highlights gaps in our knowledge that need to be filled. The present overview will help researchers plan future research and standardize and promote the inclusion of former food products in livestock diets.

The Role of Insects in Sustainable Animal Feed Production for Environmentally Friendly Agriculture: A Review

The growing demand for animal protein, the efficient use of land and water, and the limitations of non-renewable energy sources highlight the global importance of edible insects. This paper provides an overview of the key issues regarding the role of edible insects in sustainable feed production and environmentally friendly agriculture. The indispensable ecological services provided by insects are discussed, as well as the farming, products, and nutritional value of edible insects. A representative selection of the literature reviewing major insect species' chemical compositions and nutritional value is also presented. The use of insect-derived feeds for animal production is presented in detail and discussed for the major terrestrial livestock and aquaculture groups.

Fat from Hermetia illucens Alters the Cecal Gut Microbiome and Lowers Hepatic Triglyceride Concentration in Comparison to Palm Oil in Obese Zucker Rats

BACKGROUND

Palm oil (PO) is the most widely utilized plant oil for food production. Owing to the great ecologic problems associated with PO production, sustainably produced fats, such as insect fat, might be a suitable alternative.

OBJECTIVES

The hypothesis was tested that fat from Hermetia illucens larvae (HF) compared with PO and soybean oil (SO) has no adverse effects on hepatic lipid metabolism, plasma metabolome, and cecal microbiome in obese Zucker rats.

METHODS

Thirty male obese Zucker rats were randomly assigned to 3 groups (SO, PO, HF; n = 10 rats/group) and fed 3 different semisynthetic diets containing either SO, PO, or HF as the main fat source for 4 wk. The effects were evaluated by measurement of liver and plasma lipid concentrations, liver transcriptomics, targeted plasma metabolomics, and cecal microbiomics.

RESULTS

Supplementation of HF reduced hepatic triglyceride concentration and messenger ribonucleic acid concentrations of selected genes involved in fatty acid and triglyceride synthesis in comparison to PO (P < 0.05). Pairwise comparison of the Simpson index and Jaccard index showed a higher cecal microbial α- and β-diversity in rats fed the HF diet than in rats fed the PO diet (P = 0.015 and P = 0.027), but no difference between rats fed the diets with SO or PO. Taxonomic analysis of the cecal microbial community revealed a lower abundance of Clostridium_sensu_stricto_1 and a higher abundance of Blautia, Mucispirillum, Anaerotruncus, Harryflintia, and Peptococcus in rats supplemented with HF than in rats supplemented with PO (P < 0.05).

CONCLUSIONS

HF, compared with PO, has liver lipid-lowering effects in obese Zucker rats, which may be caused by a shift in the gut microbial community. Thus, HF might serve as a sustainably produced fat alternative to PO for food production.

Copping out of novel feeds: HOW climate change pledgers and food summits overlooked insect protein

The intention with this critical review is to appraise recent work done on insect proteins as animal feeds, and to discuss the possible factors which led to the ruling out of insect proteins by food and feed commissioners, as well as climate change pledgers. Of late, edible insect larvae have gained popularity as a promising protein source. On the basis of proximate analysis, insect species such as Tenebrio molitor, Musca domestica, Acheta domestica, Zophobas morio and Hermetia illucens have been reported to contain substantial amounts of protein, essential amino acids and minerals. Given these chemical properties, insects may be fruitfully utilized as a partial or sole protein source for monogastric rations. Although insect larvae hold immense potential as promising sustainable protein ingredients which are both ecologically and environmentally friendly, these unconventional feedstuffs are frequently overlooked and/or excluded from policies and legislation on feedstuff of animal origin, at local and international summits which pledge to develop sustainable food systems. Concerns about food insecurity, our expanding carbon footprint and deteriorating ecosystems, dictate that food and climate change summits bring to the mitigation table the concept of transitioning animal diets. A change must be effected from standard to sustainable diets, starting with a declaration on environmental impact and climate change concerns related to soybean cultivation and marine loss due to overfishing. The available literature on the chemical properties and environmental impact of fishmeal and soyabean meal production was scrutinized by accessing electronic databases and comparing these to insects' nutritional composition and the impact which insect rearing has on the environment. As the literature search results revealed, information on the specific laws dealing with insect proteins as feed ingredients is scant, while the existing laws vary greatly. This has implications for innovation, as well as the trade in insect protein at a global level.

Effect of Hermetia illucens Fat, Compared with That of Soybean Oil and Palm Oil, on Hepatic Lipid Metabolism and Plasma Metabolome in Healthy Rats

Palm oil (PO) is currently the most widely used fat source for food production, but insect fat from Hermetia illucens larvae (HF) might be a suitable alternative fat source, because its production is less harmful to the environment. The present study investigated the effect of HF, as compared to PO and soybean oil (SO), on the hepatic lipid metabolism and the plasma metabolome of healthy rats, which were randomly assigned to three groups (n = 10 rats/group), and fed three different semi-synthetic diets containing either SO, PO, or HF as the main fat source for 4 weeks. Feed intake, body weight gain, liver and plasma lipid concentrations, and the hepatic mRNA levels of genes involved in lipid metabolism and inflammation did not differ between groups. Targeted plasma metabolomics revealed 294 out of 630 metabolites analyzed to be different between groups. Principal component analysis showed a clear separation of the plasma metabolomes of the SO group and the other two groups, but no separation of those of the PO and the HF groups. The present study shows that HF exerts no adverse metabolic effects in healthy rats, compared to PO or SO, indicating that HF is a safe alternative fat source to PO for food production.

Advances in selenium supplementation: From selenium-enriched yeast to potential selenium-enriched insects, and selenium nanoparticles

Selenium (Se) is an essential micronutrient that plays an important role in animal and human development and physiological homoeostasis. This review surveys the role of Se in the environment, plants and animal bodies, and discusses data on Se biofortification with different sources of supplementation, from inorganic to organic forms, with special focus on Se-enriched yeast (Se-yeast). Although Se-yeast remains one of the main sources of organic Se, other emerging and innovative sources are reviewed, such as Se-enriched insects and Se-nanoparticles and their potential use in animal nutrition. Se-enriched insects are discussed as an option for supplying Se in organic form to livestock diets. Se-nanoparticles are also discussed, as they represent a more biocompatible and less toxic source of inorganic Se for animal organisms, compared to selenite and selenate. We also provide up to date information on the legal framework in the EU, USA, and Canada of Se that is contained in feed additives. From the scientific evidence available in the literature, it can be concluded that among the inorganic forms, sodium selenite is still one of the main options, whereas Se-yeast remains the primary organic form. However, other potential sources such as Se-enriched insects and Se-nanoparticles are being investigated as they could potentially combine a high bioavailability and reduced Se emissions in the environment.

Review: Effect of Experimental Diets on the Microbiome of Productive Animals

The microorganisms that inhabit the gastrointestinal tract are responsible for multiple chains of reactions that affect their environment and modify the internal metabolism, their study receives the name of microbiome, which has become more relevant in recent years. In the near future, the challenges related to feeding are anticipated to escalate, encompassing the nutritional needs to sustain an overpopulated world. Therefore, it is expected that a better understanding of the interactions between microorganisms within the digestive tract will allow their modulation in order to provide an improvement in the immune system, feed efficiency or the promotion of nutritional characteristics in production animals, among others. In the present study, the main effects of experimental diets in production animals were described, emphasizing the diversity of the bacterial populations found in response to the diets, ordering them between polygastric and monogastric animals, and then describing the experimental diets used and their effect on the microorganisms. It is hoped that this study will help as a first general approach to the study of the role of the microbiome in production animals under different diets.

Review: Composition and utilisation of feed by monogastric animals in the context of circular food production systems

Food production has a major impact on environmental emissions, climate change and land-use. To reduce this impact, the circularity of future food production systems is expected to become increasingly important. In a circular food system, crop land is primarily used for plant-based food production, while low-opportunity cost feed materials (LCF), i.e. crop residues, co-products of the food industry, grass from marginal land and food waste form the basis of future, animal feeds. Animal diets thus contain much less cereals and soybean meal and include a higher proportion of diverse co-products, residues and novel human-inedible ingredients. These diets are characterised by a lower starch content, and a higher content of fibre, protein, fat, and phytate compared to present diets. In this review, possible consequences of the development towards a more circular food system for the type, volume and nutritional characteristics of feed materials and complete feeds are addressed and related research questions in the area of animal nutrition, physiology and metabolism are discussed. Additional attention is given to possible effects on intestinal health and gut functionality and to (bio)technological processing of LCF to improve their suitability for feeding farm animals, with a focus on the effects in pigs and poultry. It is concluded that an increased use of LCF may limit the use of presently used criteria for the efficiency of animal production and nutrient utilisation. Development of characteristics that reflect the efficacy and efficiency of the net contribution of animal production in a circular food system is required. Animal scientists can have an important role in the development of more circular food production systems by focussing on the optimal use of LCF in animal diets for the production of animal-source food, while minimising the use of human-edible food in animal feed.

Review: Pig-based bioconversion: the use of former food products to keep nutrients in the food chain

The primary challenge of agriculture and livestock production is to face the growing competition between food, feed, fibre, and fuel, converting them from resource-intensive to resource-efficient. A circular economy approach, using agricultural by-products/co-products, in the livestock production system would allow to reduce, reuse, and redistribute the resources. Former food products (FFPs), also named ex-foods, could represent a valid option in strengthening resilience in animal nutrition. FFPs have a promising potential to be included regularly in animal diets due to their nutritive value, although their potential in animal nutrition remains understudied. A thorough investigation of the compositional and dietary features, thus, is essential to provide new and fundamental insights to effectively reuse FFPs as upgraded products for swine nutrition. Safety aspects, such as the microbial load or the presence of packaging remnants, should be considered with caution. Here, with a holistic approach, we review several aspects of FFPs and their use as feed ingredients: the nutritional and functional evaluation, the impact of the inclusion of FFPs in pigs' diet on growth performance and welfare, and further aspects related to safety and sustainability of FFPs.

Could Insect Products Provide a Safe and Sustainable Feed Alternative for the Poultry Industry? A Comprehensive Review

The planet is home to more than 2000 species of edible insects, some of which have been consumed as food for many years. Recently, edible insect products have been gradually increasing in several countries, such as Italy and Egypt, as novel feed resources for humans and animals due to their availability, potential economic benefits, and high nutritive value. The insect industry can provide a new solution for livestock nutrition and offer many additional advantages, but there are obstacles to overcome, such as some nutritional organizations that forbid its usage. Nevertheless, previous research indicates that different insect species could be used safely as nutraceuticals in poultry farming to improve broiler growth performance (>3%) and layer egg production (>5%). Among these species, there are various products and extracts that can be used in poultry nutrition in a sustainable manner. This review provides an outline of insect composition, nutrient values, application in poultry feed, safety, and guidelines, and finally, the future perspectives of insects as an alternative feed source in poultry diets.

Packaging contaminants in former food products: Using Fourier Transform Infrared Spectroscopy to identify the remnants and the associated risks

Food waste and feed-food competition can be reduced by replacing traditional feed ingredients such as cereals, with former food products (FFPs) in livestock diets. These foodstuffs, initially intended for human consumption, are recovered, mechanically unpacked, and then ground. Despite this simple and inexpensive treatment, packaging contaminants (remnants) are often unavoidable in the final product. To maximize the exploitation of FFPs and to minimize the associated risks, packaging remnants need to be quantified and characterized. This study tested the efficacy of the Fourier Transform Infrared Spectroscopy coupled with an optical microscope (μFT-IR) in identifying packaging remnants in 17 FFP samples collected in different geographical areas. After a visual sorting procedure, presumed packaging remnants were analyzed by μFT-IR. The results showed significant differences (p < 0.05) between the FFPs in terms of the total number of foreign particles found (plastics, cellulose and aluminum remnants, ranging from 4 to 19 particles per 20 g fresh matter), and also regarding the number of cellulose and aluminum particles. These data clearly demonstrate the need for sensitive instruments that can characterize the potential contaminants in the FFPs. This would then help to reduce the overestimation of undesirable contaminants typical of simple visual sorting, which is currently the most common method.

Contamination of Zophobas morio Larvae Rearing Substrate with Listeria monocytogenes: A Preliminary Study

The interest in edible insects is continuously increasing due to their environmental, nutritional, and productive features. The aim of this study was to evaluate the effects and survival of Listeria monocytogenes in Zophobas morio rearing, using two different bacterial loads (2 and 6 log CFU/g). We also considered the effect of washing, fasting, and cooking treatments on the larvae. During the experimental trial, no mortality was observed among the larvae. The L. monocytogenes loads decreased over time, and it was below the detection limit for crates inoculated with 2 log CFU/g, while the substrate inoculated with 6 log CFU/g reached loads of 4.26 (without larvae) and 2.83 log CFU/g (with larvae). Due to the absence of L. monocytogenes in the larvae on day seven, it was not possible to assess the fasting treatment or the washing and the cooking. However, when looking at the total microbial count, significant effects were revealed for all treatments. The unfasted larvae showed no effect of washing, while the total microbial counts decreased after washing in the fasted larvae. This proves that fasting is a good treatment in terms of hygiene assurance for the consumer.

Effect of replacement of soybean oil by Hermetia illucens fat on performance, digestibility, cecal microbiome, liver transcriptome and liver and plasma lipidomes of broilers

BACKGROUND

In contrast to protein-rich insect meal, the feed potential of insect fat is generally less explored and knowledge about the suitability of insect fat as a fat source specifically in broiler diets is still limited. In view of this, the present study aimed to comprehensively investigate the effect of partial (50%) and complete replacement of soybean oil with insect fat from Hermetia illucens (HI) larvae in broiler diets on performance, fat digestibility, cecal microbiome, liver transcriptome and liver and plasma lipidomes. Thus, 100 male, 1-day-old Cobb 500 broilers were randomly assigned to three groups and fed three different diets with either 0 (group HI-0, n = 30), 2.5% (group HI-2.5, n = 35) or 5.0% (HI-5.0, n = 35) Hermetia illucens (HI) larvae fat for 35 d.

RESULTS

Body weight gain, final body weight, feed intake, and feed:gain ratio during the whole period and apparent ileal digestibility coefficient for ether extract were not different between groups. Cecal microbial diversity did not differ between groups and taxonomic analysis revealed differences in the abundance of only four low-abundance bacterial taxa among groups; the abundances of phylum Actinobacteriota, class Coriobacteriia, order Coriobacteriales and family Eggerthellaceae were lower in group HI-5.0 compared to group HI-2.5 (P < 0.05). Concentrations of total and individual short-chain fatty acids in the cecal digesta were not different between the three groups. Liver transcriptomics revealed a total of 55 and 25 transcripts to be differentially expressed between groups HI-5.0 vs. HI-0 and groups HI-2.5 vs. HI-0, respectively (P < 0.05). The concentrations of most lipid classes, with the exception of phosphatidylethanolamine, phosphatidylglycerol and lysophosphatidylcholine in the liver and cholesterylester and ceramide in plasma (P < 0.05), and of the sum of all lipid classes were not different between groups.

CONCLUSIONS

Partial and complete replacement of soybean oil with HI larvae fat in broiler diets had no effect on growth performance and only modest, but no adverse effects on the cecal microbiome and the metabolic health of broilers. This suggests that HI larvae fat can be used as an alternative fat source in broiler diets, thereby, making broiler production more sustainable.

Effects of black soldier fly larvae as protein or fat sources on apparent nutrient digestibility, fecal microbiota, and metabolic profiles in beagle dogs

Black soldier fly (Hermetia illucens) larvae (BSFL) act as a biological system converting organic waste into protein and fat with great potential application as pet food. To evaluate the feasibility of BSFL as a protein and fat source, 20 healthy beagle dogs were fed three dietary treatments for 65 days, including (1) a basal diet group (CON group), (2) a basal diet that replaced 20% chicken meal with defatted black soldier fly larvae protein group (DBP group), and (3) a basal diet that replaced 8% mixed oil with black soldier fly larvae fat group (BF group). This study demonstrated that the serum biochemical parameters among the three groups were within the normal range. No difference (p > 0.05) was observed in body weight, body condition score, or antioxidant capacity among the three groups. The mean IFN-γ level in the BF group was lower than that in the CON group, but there was no significant difference (p > 0.05). Compared with the CON group, the DBP group had decreasing (p < 0.05) apparent crude protein and organic matter digestibility. Furthermore, the DBP group had decreasing (p < 0.05) fecal propionate, butyrate, total short-chain fatty acids (SCFAs), isobutyrate, isovalerate, and total branched-chain fatty acids (BCFAs) and increased (p < 0.05) fecal pH. Nevertheless, there was no difference (p > 0.05) in SCFAs or BCFAs between the CON and BF groups. The fecal microbiota revealed that Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were significantly enriched in the DBP group, and Terrisporobacter and Ralstonia were significantly enriched in the BF group. The fecal metabolome showed that the DBP group significantly influenced 18 metabolic pathways. Integrating biological and statistical correlation analysis on differential fecal microbiota and metabolites between the CON and DBP groups found that Lachnoclostridium, Clostridioides, and Enterococcus were positively associated with biotin. In addition, Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were positively associated with niacinamide, phenylalanine acid, fumaric acid, and citrulline and negatively associated with cadavrine, putrescine, saccharopine, and butyrate. In all, 20% DBP restrained the apparent CP and OM digestibility, thereby affecting hindgut microbial metabolism. In contrast, 8% BF in the dog diet showed no adverse effects on body condition, apparent nutrient digestibility, fecal microbiota, or metabolic profiles. Our findings are conducive to opening a new avenue for the exploitation of DBP and BF as protein and fat resources in dog food.

Preliminary Data on Essential and Non-essential Element Occurrence in Processed Animal Proteins from Insects

Insects represent a valuable and environmentally friendly protein alternative in food and feed. The Farm to Fork strategy encouraged the reintroduction of animal by-products in feed production to optimise recycling and to valorise under-used resources. In order to grant safe and valuable feed products, this study investigated the black soldier fly (BSF) (Hermetia illucens) chemical risk. Samples collected in different steps of production (8 samples of substrate for culturing, 7 samples of larvae, 15 samples of protein meal, 18 samples of spent substrate) were analysed for microessential elements (chromium, copper, iron, nickel, selenium and zinc) and inorganic contaminants (aluminium, arsenic, cadmium, lead, tin and vanadium) by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Microessential elements were found in the following order: Fe > Zn > Cu > Ni > Se > Cr (mg kg^-1). Non-essential element concentrations were found lower than the set limits according to the European Union Regulations. The growing demand for alternative protein sources for feed production could be partially compensated by black soldier fly (BSF) (Hermetia illucens) meal, as it appears a good source for high-quality proteins and microessential elements which play a pivotal role in animal growth. In the foreseeable future the current legislation and the official monitoring plans may be implemented and broaden, to focus and assess limits for upcoming matrices, and to ensure feed and food safety.

Suppression of Methicillin-Resistant Staphylococcus aureus and Reduction of Other Bacteria by Black Soldier Fly Larvae Reared on Potato Substrate

Larvae of black soldier flies, Hermetia illucens, are increasingly used for biological conversion of animal and plant wastes into ingredients of animal feeds on an industrial scale. The presence of pathogenic microorganisms in harvested larvae may be a serious problem for wide-scale adoption of this technology. Fortunately, black soldier fly larvae may have some antimicrobial properties. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium associated with various environments that can be pathogenic to humans and farmed animals. We tested whether black soldier fly larvae suppress MRSA on potato substrate. Autoclaved potatoes containing black soldier fly larvae (P+BSFL), potatoes inoculated with MRSA and containing black soldier fly larvae (P+MRSA+BSFL), and potatoes inoculated with MRSA (P+MRSA) were incubated in glass jars. Substrate samples were taken after 3 and 7 days of incubation and plated on Trypticase soy agar (TSA) and Staphylococcus medium 110 agar (SA) to quantify total bacteria and MRSA, respectively. DNA was extracted from potato substrates on both days and sequenced to assess bacterial and fungal diversity using 515F/806R and internal transcribed spacer (ITS) 1/2 primers, respectively, and QIIME 2.0 software. Both total bacterial and MRSA-specific CFU were reduced in the presence of black soldier fly larvae, with a larger reduction for the latter. Twenty-five bacterial genera and 3 fungal genera were detected. Twenty bacterial genera were shared among the treatments and the days, but their relative abundances often varied. Among the most abundant genera, only Enterococcus and Lactococcus were universally present. Our findings confirm antimicrobial properties of black soldier fly larvae. IMPORTANCE Larvae of black soldier flies, Hermetia illucens, may be used to provide an environmentally sustainable and economically viable method for biological conversion of animal and plant wastes into ingredients of animal feeds on an industrial scale. However, contamination of harvested larvae by pathogenic microorganisms inhabiting decaying substrates may be a serious problem for wide-scale adoption of this technology. Fortunately, black soldier fly larvae may have some antimicrobial properties, including suppression of several common pathogens. Our study showed that such a suppression applies to methicillin-resistant Staphylococcus aureus, which is a ubiquitous bacterium pathogenic to animals (including humans).

Food system by-products upcycled in livestock and aquaculture feeds can increase global food supply

Many livestock and aquaculture feeds compete for resources with food production. Increasing the use of food system by-products and residues as feed could reduce this competition. We gathered data on global food system material flows for crop, livestock and aquaculture production, focusing on feed use and the availability of by-products and residues. We then analysed the potential of replacing food-competing feedstuff-here cereals, whole fish, vegetable oils and pulses that account for 15% of total feed use-with food system by-products and residues. Considering the nutritional requirements of food-producing animals, including farmed aquatic species, this replacement could increase the current global food supply by up to 13% (10-16%) in terms of kcal and 15% (12-19%) in terms of protein content. Increasing the use of food system by-products as feed has considerable potential, particularly when combined with other measures, in the much-needed transition towards circular food systems.

Fate of Salmonella enterica Typhimurium and Listeria monocytogenes in Black Soldier Fly (Hermetia illucens) Larvae Reared on Two Artificial Diets

Ensuring food security is one of the main challenges facing the world over the next 30 years. There is, thus, an urgent need to significantly increase the supply of sustainable protein that can be transformed into animal feed. Proteins from insects offer a valuable alternative. This article presents the results of challenge tests conducted to investigate the dynamics of the microbial load of Salmonella enterica Typhimurium and Listeria monocytogenes in black soldier fly (Hermetia illucens) larvae grown on contaminated substrates. Four separate challenge tests were performed on two substrates: the Gainesville diet and a homemade diet. The challenge test procedure was carried out in accordance with ISO/DIS 20976-2 (under development). The results of this study show that, when grown on contaminated substrates, BSF larvae do not eliminate Salmonella Typhimurium or L. monocytogenes, but can reduce their microbial load. Sanitation processes downstream of the breeding of BSF larvae are, however, required to reduce the microbiological risks of this novel food.

The Influence of Non-Optimal Rearing Conditions and Substrates on the Performance of the Black Soldier Fly (Hermetia illucens)

Simple Summary

The black soldier fly is one of the insect species most frequently reared as an alternative protein source. Even though many advances have been made in the last decade regarding environmental and process conditions, there are still several gaps that can delay the upscaling of industrial production systems. One of such gaps is related to the effect of suboptimal feeding regimes of mono-waste streams. This research aims to assess the development and bioconversion behaviour of black soldier fly larvae under suboptimal conditions. It was observed that specific types of vegetable and fruit wastes, such as apple, spinach and grape pomace, may contribute to achieve low insect biomass yields and, thus, reduce the efficiency of industrial operations.

Abstract

Among the insect species reared as alternative protein sources, Hermetia illucens (black soldier Fly, BSF) has shown a huge potential mostly due to its high protein content, its bioconversion rates, and versatility in using different feeding substrates. Insect rearing may use continuous or batch feeding regimes and, among the used substrates, supermarket feedstock waste has gained recent interest under a circular economy perspective, but several uncertainties remain regarding the heterogeneity and the potential effects of the quantity and quality of these substrates on BSF larvae (BSFL) development. In this experimental work, five replicates of a hundred BSFL were fed in a continuous feeding regime, using seven different isolated vegetables as substrates (wheat bran, pumpkin, apple, grape pomace, red onion, red cabbage, and spinach), at three different temperatures (20, 25, and 30 °C) and two substrate moisture conditions (natural and 70% substrate moisture), until 50% of the larvae achieved the prepupal stage. BSFL performance and bioconversion parameters were evaluated. Our results show that some substrates should be avoided when rearing Hermetia illucens on feedstocks. Among these, apple feed led to poorer and slower development performances with more than 100 days of larval stage, while grape pomace and spinach showed higher mortality rates, which may be due to some anti-nutritional compounds. Larvae fed on pumpkin, red cabbage, and red onion presented good bioconversion results with higher values of efficiency of conversion of digested feed between 14.4 and 25. This work delivers relevant results for black soldier fly reared on a continuous feeding system using vegetable feedstock substrates and their potential trade-offs.

Environmental performance of insect protein: a case of LCA results for fish feed produced in Norway

In this article, life cycle assessments for six insect protein production cases are examined, and their life cycle inventories are systematically combined to create consistent data and results for the environmental performance of insect protein. The LCAs are on mealworms farmed in the Netherlands or France, fed on cereals or vegetable waste food and brewery side stream (four cases); and black soldier fly larvae farmed in Germany, fed on brewery side stream or brewery side stream with vegetable waste (two cases). The focus is on those insect proteins which can be utilised as fish feed with use in Norway as an example. Special attention is paid to obtain consistent system boundaries, method choices, background data, and indicators. The results show that the insect diet is crucial for all the analysed environmental indicators for insects fed a diet of high economic value vegetables. Emissions from the utilisation of insect manure for biogas, fertilisers or similar, and direct insect greenhouse gas emissions, seem to have little importance. The article further shows results compared with the greenhouse gas emissions for the most important salmon protein feed ingredients in Norway. Insect protein based on vegetables with low economic value has the potential to compete in environmental performance with existing protein sources for fish feed and can also cover 10 to 15% of the volumes of crude protein currently imported to the EU.

Farm to Institution to Farm: Circular Food Systems With Native Entomoculture

Edible insects recycle food waste, which can help feed a hungrier planet by making food systems more circular and diversifying protein production. The potential for entomophagy (i.e., insect cuisine) to contribute to waste recycling and lower input food production is only beginning to be explored in the U.S., although insects have been consumed by people for millennia in a wide range of cultures. In this perspective piece, we consider as a case study the potential for university foodservice programs in New England to serve as incubators for circular entomophagous food systems. Students are likely early adopters of entomophagy because they increasingly demand sustainable non-meat protein options. University foodservices meanwhile purchase large amounts of food wholesale from local producers, utilize standardized pre-processing, and generate consistent waste streams which may be valuable feed for local insect farmers. Current Farm to Institution approaches strengthen regional food systems by connecting small farmers with university foodservices; we argue that a similar model (Farm to Institution to Farm) could support establishment of local insect farms, introduce edible insects to a relatively receptive base of university student customers, and provide a more sustainable mechanism for repurposing university food waste as insect feed. But to enable this type of food system, additional requirements include: (1) research on domestication of native insect species; (2) investment in processing capacity, ensuring new insect farmers have reliable markets for raw insect products; (3) infrastructure to recirculate waste streams within existing food systems; and (4) creation of recipes that entice new insect consumers.

Fluorescence-based characterisation of selected edible insect species: Excitation emission matrix (EEM) and parallel factor (PARAFAC) analysis

Fluorescence spectroscopy coupled with chemometric tools is a powerful analytical method, largely used for rapid food quality and safety evaluations. However, its potential has not yet been explored in the novel food sector. In the present study, excitation emission matrices (EEMs) of 15 insect powders produced by milling insects belonging to 5 Orthoptera species (Acheta domesticus, Gryllus assimilis, Gryllus bimaculatus, Locusta migratoria, Schistocerca gregaria) from 3 different origins were investigated. Parallel factor (PARAFAC) analysis performed on the overall averaged dataset was validated for five components, highlighting the presence of five different fluorescence peaks. The presence of these peaks was confirmed on each species, suggesting that fluorescence compounds of edible insects are the same in several species. PARAFAC analysis performed on the overall averaged dataset after alternatively adding the EEM recorded from one standard compound allowed to speculate that edible insects fluorescence raises from mixtures of: tryptophan + tyrosine (PARAFAC component-1), tryptophan + tyrosine + tocopherol (PARAFAC component-2), collagen + pyridoxine + pterins (PARAFAC component-3). This study suggests that fluorescence spectroscopy may represent a powerful method for investigating composition and quality of insect-based foods.

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Fluorescence landscape of edible insects comprises of 5 different peaks.

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Similar fluorescence compounds are present among several Orthoptera species.

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Fluorescence peaks of edible insects result from several chemical molecules.

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Fluorescence intensity of edible insects depends on their species and origin.

Habitat-centric versus species-centric approaches to edible insects for food and feed

The current paradigm of the edible insects for food and feed industry uses a species-centric approach in which an insect species is chosen first and development of rearing practices follows. The goal is to optimize production to maximize the yield of that species in that facility. In contrast, the habitat-centric approach first chooses a habitat, either natural or artificial, then develops harvesting or rearing protocols within that habitat. The goal of this approach is to maximize the yield derived from that habitat. The habitat-centric approach eliminates potential threats from invasive species, and can repurpose local food and agricultural waste into protein derived from local insect species. This approach can increase food security by increasing the diversity of insects that are mass-produced. The species-centric and habitat-centric approaches address different issues and offer advantages in different situations. Further development of the edible insect industry will likely use a combination of both approaches.

Italian Consumers' Readiness to Adopt Eggs from Insect-Fed Hens

Simple Summary

An overall increase in food demand is pushing the agri-food sector toward higher food output. In particular, the feeding of laying hens plays a major role, requiring larger quantities of soybean meal for egg production each year. Replacing soybean meal with insect meal has proven to lower the environmental impact compared to traditional feed production, but it may influence consumer acceptance. An online survey was conducted to evaluate the perception and the readiness of Italian consumers to the use of eggs from laying hens fed with insect meal. The results showed a considerable level of willingness of the participants to face this innovative scenario.

Abstract

Demand for eggs from laying hens is increasing as the world population continues to grow. The use of insects as animal feed is a strategic opportunity to find a new innovative, economic and sustainable source of protein. The aim of this study was to evaluate the Italian consumer inclination for eggs produced with the use of insect-fed hens. The investigation on consumers’ readiness to adopt eggs from insect-fed hens was carried out through an online survey conducted on 510 participants. Survey results outlined four different clusters on the basis of the willingness to buy/eat eggs fed with insects: “ready” (40.1%), “environmentalist” (24.3%), “cautious” (21.7%), and “reluctant” (13.9%). “Ready”, “environmentalist”, and “cautious” were quite favorable to the use of insects as feed stuffs and share drivers for product choice: cheap, organic, and with an explicit indication of use of insects. On the other hand, for the “reluctant”, the diet based on insects was the main negative factor influencing product acceptance. This cluster also showed the highest level of neophobia. Italian consumers showed a considerable level of readiness to accept insects as feed material for egg production, which should be reinforced with further information on the origin and the environmental benefit of using insects.

Valorisation Potential of Using Organic Side Streams as Feed for Tenebrio molitor, Acheta domesticus and Locusta migratoria

Due to increasing welfare and population, the demand for alternative protein sources, obtained with minimal use of natural resources, is rising in today's society. Insects have the potential to be used as an alternative protein source since they are considered to be able to convert low-value biomass into high-value components, resulting in opportunities for valorisation of organic side streams. Moreover, insects are suggested to be a sustainable protein source, referring to the efficient "feed to body" mass conversion potential. The aim of this review was to explore the potential to rear the yellow mealworm (Tenebrio molitor), the house cricket (Acheta domesticus) and the migratory locust (Locusta migratoria) on low or not yet valorised organic side streams within the food supply chain. This was performed by collecting research information focusing on the rearing of the insects in scope on organic biomass. In addition, the nutritional composition of the produced insects as well as their dietary requirements will be reviewed. Finally, the availability of side streams in the EU will be discussed as well as their potential to be used as insects feed.

Mealworm (Tenebrio molitor): Potential and Challenges to Promote Circular Economy

Simple Summary

The main objective of this review is to analyse the potential of insects from the perspective of circular economy, focusing our attention on mealworm larvae. After pointing out the key concepts of circular economy and describing the use of insects in bioconversion processes, we discuss the most relevant uses of the mealworm in different industries, which show the great contribution this insect can make within circular productive systems. This topic has attracted a lot of attention due to its implications from an economic and environmental point of view. Recently, mealworm larvae were positively assessed by European Food Safety Authority (EFSA) as a safe novel food. As a matter of fact, the mealworm is the first edible insect to achieve this important milestone in the EU. Due to this new scientific opinion, considerable expectations arise on mealworms and their potential in different fields, which will surely lead to market developments in the following years.

Abstract

Over the last few years, the concept of Circular Economy (CE) has received a lot of attention due to its potential contribution to the Sustainable Development Goals (SDGs), especially by reconciling economic growth with the protection of the environment through its grow-make-use-restore approach. The use of insects in circular production systems has been a good example of this concept as insects can transform a wide range of organic waste and by-products into nutritious feedstuffs, which then go back into the production cycle. This paper explores the potential of mealworms (Tenebrio molitor) in circular production systems by reviewing their use and applicability in several industries such as pharmaceuticals, agriculture, food, etc. Despite the high versatility of this insect and its potential as a substitute source of nutrients and other valuable components, there are still many legislative and behavioural challenges that hinder its adoption and acceptance.

Insect Protein-Based Diet as Potential Risk of Allergy in Dogs

Before insects can be used widely as an alternative source of dietary protein, their allerginicity should be investigated. Therefore, the aim of our study was to assess the potential adverse reactions of the immune system of dogs against Tenebrio molitor proteins. Dogs sensitised to storage mites T. putrescentiae and A. siro were included. Clinically healthy and clinically allergic dogs were compared. Proteins were extracted from mealworm larvae and their digestibility determined by in vitro incubation with digestive proteases. Mealworm protein extracts and digests were analysed by SDS-PAGE. Canine sera tested for the presence of mite-specific IgEs were used for subsequent Western blotting. LC-MS/MS analysis was used to identify mealworm proteins and their allergenic potential was predicted with the AllermatchTM tool. The binding of canine sera IgEs to mealworm proteins was confirmed; however, the differences between the two groups of dogs were not significant. Moreover, no clear correlation was found between sensitisation to storage mites and clinical status of the dogs. Altogether, 17 different proteins were identified, including tropomyosin, α-amylase, and Tm-E1a cuticular protein that are known cross-reacting IgE-binding allergens. Our results suggest that dogs allergic to mites may clinically express also the cross-reactivity with mealworm proteins.

Effect of Cooking Techniques on the in vitro Protein Digestibility, Fatty Acid Profile, and Oxidative Status of Mealworms (Tenebrio molitor)

Tenebrio molitor (T. molitor) (mealworm) larvae are one of the most promising insects for feed–food purposes. Mealworms are rich in several macro and micro nutritional elements and can be practically reared on side stream substrates. In this study, the effects of seven different cooking techniques were tested on the nutritional value of mealworms focusing the attention on protein digestibility, fatty acid (FA) profile, and oxidative status. Uncooked larvae (UC) were used as control and compared to two combinations of temperature/time in oven cooking (70°C for 30 min, OC70-30, 150°C for 10 min, OC150-10), two methods of frying (mealworms fried in sunflower oil as deep fry, DF, or pan fry, PF), microwaving (MW), boiling (in plastic bag under vacuum, BO), and steaming (ST). Proximate composition, in vitro digestibility (gastric and duodenal), FA profile, and oxidative status (tocopherol and tocotrienol, carbonyl, and lipid oxidation) were then tested. Cooking technique affected all the tested parameters. As expected, cooking affected proximate composition in relation to the method applied (dry matter increased after oven cooking and frying; lipids increased by frying). In vitro digestion revealed the highest value for the OC70-30 method, followed by UC and ST. Deep frying revealed the worst digestibility percentage. FA profile was deeply affected by the cooking technique, with general decrease in SFA and MUFA. The highest modifications in FA profile were revealed in ST larvae with an increased percentage of linoleic acid linked to the lowering of SFA and MUFA contents. Furthermore, deep frying larvae in sunflower oil increased the relative abundance of PUFAs. Tocols values were higher in DF and MW groups than PF (about 6-fold more) and all other groups (7-fold more). Carbonyls increased with oven cooking (OC150-10 and OC70-30), whereas the values were lower with frying and similar to ST and UC. Lipid oxidation was highest as well in OC150-10 but similar to frying methods (DF and PF). Based on the obtained results, it can be concluded that mealworm larvae surely meet human nutritional requirements, but the cooking method must be carefully chosen to maintain a high nutritional value.

Cost-Effectiveness of Black Soldier Fly Larvae Meal as Substitute of Fishmeal in Diets for Layer Chicks and Growers

The acceptance of eco-friendly black soldier fly larvae meal (BSFLM) as sustainable alternative protein ingredient in poultry feeds continues to gain momentum worldwide. This study evaluates the impact of BSFLM in layer chick and grower diets on the growth, carcass quality and economic returns. Mean weekly weight gain and total live weight per chick and grower varied significantly. The highest final weight gain was achieved when birds were provided diet with 25.6% BSFLM. Average daily feed intake (ADFI), average daily weight gain (ADG) and overall weight gain of the chick varied significantly, except for the feed conversion ratio (FCR). For grower birds, ADFI, ADG, FCR and overall weight gain did not vary significantly across the various feeding regimes. The weight of the wings and drumsticks had a quadratic response with a maximum weight obtained at 33% inclusion of BSFLM. The weight of the internal organs were not significantly affected by dietary types. Positive cost–benefit ratio and return on investment was recorded for diet types with higher BSFLM inclusion levels (>75%). Diets with 25% and 100% BSFLM inclusion were the most suitable and cost-effective, respectively. Thus, BSFLM represents a promising alternative source of protein that could be sustainably used in the poultry industries.

Animal Protein Sources as a Substitute for Fishmeal in Aquaculture Diets: A Systematic Review and Meta-Analysis

Fishmeal is the main source of dietary protein for most commercially farmed fish species. However, fishmeal prices have been raised even further because of competition with domestic animals, shortage in world fishmeal supply, and increased demand. Increased fishmeal prices have contributed to the quest for alternatives necessary to replace fishmeal as a global research priority. A literature search was conducted using these terms on Google Scholar and EBSCOhost; fishmeal replacement in fish feeds, fishmeal alternatives in fish feeds, animal protein sources in aquaculture, insects in fish feeds, terrestrial by-products, and fishery by-products. To calculate the variation between experiments, a random effect model was used. Results indicated that different fish species, sizes, and inclusion levels were used in the various studies and showed that the use of insects, terrestrial by-products, and fishery by-products has some limitations. Despite these drawbacks, the use of animal protein sources as a replacement for fishmeal in fish diets has had a positive impact on the feed conversion ratio, variable growth rate, final weight, and survival rate of different types of fish species of different size groups. Findings also showed that some animal by-products had not been assessed as a protein source in aquaculture or animal feeds, and future studies are recommended.

Black soldier fly larvae meal and fat can completely replace soybean cake and oil in diets for laying hens

Currently, there is a great interest in finding alternative protein and energy sources to replace soybean-based feeds in poultry diets. The main objective of the present study was to completely replace soybean in layer diets with defatted meal and fat from black soldier fly larvae without adverse effects. For this purpose, 5 × 10 Lohmann Brown Classic hens were fed either a soybean-based diet or diets based on defatted black soldier fly larvae meal and fat from 2 producers (1 commercial, 1 small-scale) operating with different rearing substrates, temperatures, and larvae processing methods (10 hens/diet). The data obtained included nutrient composition of larvae meals and diets, amino acid digestibility (6 hens/diet), and metabolizability, performance and egg quality (all 10 hens/diet). In addition, the acceptance of the 4 larvae-based diets was tested against the soybean-based diet in a 6-day choice feeding situation (10 hens/treatment). The nutritional value of the larvae-based diets was equivalent to the soybean-based diet in hens with a laying performance of 98%. Although average feed intake was not significantly different over the 7 experimental weeks, the diets based on larvae feeds from the small-scale production appeared to be slightly less accepted in a choice situation than the soy-based diet and those with larvae from commercial origin. This was more likely the effect of the larvae fat rather than that of the larvae protein meal. In addition, the commercial larvae material was superior to that from the small-scale production concerning supply with digestible sulfur-containing amino acids (548 vs. 511 mg/day) and lysine (792 vs. 693 mg/day), egg weight (67 vs. 63 g), daily egg mass (66 vs. 61 g/day) and, in tendency, feed efficiency. The results indicate that soybean-based feeds can be replaced completely by black soldier fly meal and fat in diets of high-performing layers. However, because of nutritional differences between the larvae materials of different origin the quality of the larvae has to be closely monitored before being used.

Effects of full replacement of dietary fishmeal with insect meal from Tenebrio molitor on rainbow trout gut and skin microbiota

Background

Aquaculture must continue to reduce dependence on fishmeal (FM) and fishoil in feeds to ensure sustainable sector growth. Therefore, the use of novel aquaculture feed ingredients is growing. In this regard, insects can represent a new world of sustainable and protein-rich ingredients for farmed fish feeds. Accordingly, we investigated the effects of full replacement of FM with Tenebrio molitor (TM) larvae meal in the diet of rainbow trout (Oncorhynchus mykiss) on fish gut and skin microbiota.

Methods

A feeding trial was conducted with 126 trout of about 80 g mean initial weight that were fed for 22 weeks with two isonitrogenous, isolipidic, and isoenergetic extruded experimental diets. Partially defatted TM meal was included in one of the diets to replace 100% (TM 100) of FM, whereas the other diet (TM 0) was without TM. To analyse the microbial communities, the Illumina MiSeq platform for sequencing of 16S rRNA gene and Qiime pipeline were used to identify bacteria in the gut and skin mucosa, and in the diets.

Results

The data showed no major effects of full FM substitution with TM meal on bacterial species richness and diversity in both, gut mucosa- and skin mucus-associated microbiome. Skin microbiome was dominated by phylum Proteobacteria and especially by Gammaproteobacteria class that constituted approximately half of the bacterial taxa found. The two dietary fish groups did not display distinctive features, except for a decrease in the relative abundance of Deefgea genus (family Neisseriaceae) in trout fed with insect meal. The metagenomic analysis of the gut mucosa indicated that Tenericutes was the most abundant phylum, regardless of the diet. Specifically, within this phylum, the Mollicutes, mainly represented by Mycoplasmataceae family, were the dominant class. However, we observed only a weak dietary modulation of intestinal bacterial communities. The only changes due to full FM replacement with TM meal were a decreased number of Proteobacteria and a reduced number of taxa assigned to Ruminococcaceae and Neisseriaceae families.

Conclusions

The data demonstrated that TM larvae meal is a valid alternative animal protein to replace FM in the aquafeeds. Only slight gut and skin microbiota changes occurred in rainbow trout after total FM replacement with insect meal. The mapping of the trout skin microbiota represents a novel contribution of the present study. Indeed, in contrast to the increasing knowledge on gut microbiota, the skin microbiota of major farmed fish species remains largely unmapped but it deserves thorough consideration.

Impact of Agro-industrial Byproducts on Bioconversion, Chemical Composition, in vitro Digestibility, and Microbiota of the Black Soldier Fly (Diptera: Stratiomyidae) Larvae

The interest in using byproducts from agro-food industries as a rearing substrate for insects is increasing rapidly. We investigated the influence of byproducts of vegetal origin (okara-a byproduct of soy milk production, maize distillers with solubles, brewer's grains), used as rearing diet for black soldier fly larvae (BSFL), on the following parameters: biomass production, substrate reduction (SR), nutritional profile and in vitro digestibility, and larval gut microbiota. Hen diet was used as a control substrate. The highest larval biomass was collected on maize distillers, whereas the highest SR was observed on okara. The rearing substrate affected ash, ether extract, and chitin larval content. The BSFL reared on okara were characterized by a lower lauric acid content (17.6% of total fatty acids). Diets also influenced in vitro crude protein digestibility (%) for monogastrics, with the highest values for BSFL reared on maize distillers (87.8), intermediate for brewer's grains and okara BSFL, and the lowest for hen BSFL (82.7). The nutritive value for ruminants showed a lower Net Energy for lactation for BSFL reared on hen diet than okara and dried maize distillers BSFL. The different byproducts showed an influence on the larval gut microbiota, with a major bacterial complexity observed on larvae fed with the hen diet. The neutral detergent fiber concentration of dietary substrate was negatively correlated with Firmicutes and Actinobacteria relative abundance. Insects valorized byproducts converting them into high-value larval biomass to be used for feed production. The results evidenced the effects of the tested byproducts on the measured parameters, underling the chemical composition importance on the final insect meal quality.

Effects of dietary energy content and source using by-products on carcass and meat quality traits of cull ewes

In cull ewes, energy supply by time short periods can affect growth, carcass traits, and meat quality. The objective of this study was to evaluate the effect of biscuit bran (BB) and cashew nut bran (CNB) in diets with different total digestible nutrient (TDN) content on animal performance and carcass and meat traits of cull ewes. Twenty Morada Nova cull ewes, with the initial BW of 30.1 ± 3.56 kg, and three years of age were distributed in a completely randomized design into factorial scheme 2 × 2, with two energy sources (BB and CNB) × two levels of TDN. All diets were isoproteic with variations in TDN content increased by 10% (TDN10) and 25% (TDN25) above the recommended requirement for the study category, which was 66.0% TDN. The experimental period lasted 56 days, in which daily intake in relation to metabolic weight and weight performance of the animals was determined. The hot carcass, the cold carcass, commercial cuts, loin eye area, and subcutaneous fat thickness were measured, obtained, or calculated. A sample of the Longissimus lumborum (LL) muscle was used by determination of physical-chemical composition, sensory, and fatty acid (FA) profile analysis. The ANOVA was performed to access the effect of diet and energy level on the characteristics studied, and means were compared by the Turkey and Kruskal Wallis tests at 5% of probability. A higher daily gain weight was observed from TDN25 (P = 0.006). Among by-products, higher nutrient intakes were observed in animals fed with BB diets (P < 0.01), except for crude protein. The same patterns have been observed for live weight, reconstituted half-carcass, higher yield in fat thickness, and internal carcass length. Cashew nut bran produced darker colored meat (P = 0.017) and higher cooking weight loss (P = 0.008). Higher lipid content was observed in animals submitted to diets with CNB and TDN25 (P = 0.001). The internal length of the carcass was higher in animals fed with BB (P = 0.041). All diets did not effect on sensory characteristics (P > 0.05). Total digestible nutrient in 25% above recommended promotes higher weight gain and meat with higher lipid content and less weight loss by cooling. The inclusion of BB, compared to CNB, provides a higher weight of carcasses and better conformation, in addition to lower total lipid content with higher proportion for monounsaturated FAs in meat, providing more attractive features for the consumer market.

Insect Fat in Animal Nutrition – A Review

The aim of this review is to discuss the usage of insect fats as an energy source in animal nutrition. Insects are a rich carrier of proteins, fat, and minerals. They are successfully introduced in animal diets (poultry, swine, rabbits, fish, and pets) as a source of many nutrients, including energy and essential fatty acids (FAs). The insects’ fat content and quality are highly affected by the type of substrate provided to the insects during the rearing period. The majority of the studies have shown that insect fats may be used as promising substitutes for conventional energy resources in animal nutrition without adverse effects on growth performance and feed utilization. They can positively affect meat quality by increasing the level of long-chain polyunsaturated FAs but may also positively influence animals by regulating the gut microbiota and stimulating the immune system. In conclusion, insect fat supplementation showed promising results in terms of their application in animal nutrition. However, compared to insect protein application, very few studies have been performed on insect fats. Therefore, because of the fat quality and content of insects, there is a need to extend experimentation regarding their implementation in animals’ diets as a replacement for conventional dietary energy resources.

Larvae Mediated Valorization of Industrial, Agriculture and Food Wastes: Biorefinery Concept through Bioconversion, Processes, Procedures, and Products

Each year, the food supply chain produces more than 1.3 billion tons of food and agricultural waste, which poses serious environmental problems. The loss of the massive quantity of secondary and primary metabolites retrievable from this resource is a significant concern. What if there is a global solution that caters to the numerous problems arising due to the humongous volume of waste biomass generated in every part of the world? Insects, the tiny creatures that thrive in decaying organic matter, which can concentrate the nutrients present in dilute quantities in a variety of by-products, are an economically viable option. The bioconversion and nutritional upcycling of waste biomass with insects yield high-value products such as protein, lipids, chitin and frass. Insect-derived proteins can replace conventional protein sources in feed formulations. Notably, the ability of the black soldier fly (BSF) or Hermetia illucens to grow on diverse substrates such as agri-food industry side streams and other organic waste proves advantageous. However, the data on industrial-scale extraction, fractionation techniques and biorefinery schemes for screening the nutritional potential of BSF are scarce. This review attempts to break down every facet of insect processing and analyze the processing methods of BSF, and the functional properties of nutrients obtained thereof.

Reduce, Reuse, Recycle for Food Waste: A Second Life for Fresh-Cut Leafy Salad Crops in Animal Diets

The world's population is growing rapidly, which means that the environmental impact of food production needs to be reduced and that food should be considered as something precious and not wasted. Moreover, an urgent challenge facing the planet is the competition between the food produced for humans and the feed for animals. There are various solutions such as the use of plant/vegetable by-products (PBPs) and former foodstuffs, which are the co/by-products of processing industries, or the food losses generated by the food production chain for human consumption. This paper reviews the by-co-products derived from the transformation of fresh-cut leafy salad crops. A preliminary nutritional evaluation of these materials is thus proposed. Based on their composition and nutritional features, in some cases similar to fresh forage and grasses, this biomass seems to be a suitable feedstuff for selected farm animals, such as ruminants. In conclusion, although the present data are not exhaustive and further studies are needed to weigh up the possible advantages and disadvantages of these materials, fresh-cut leafy salad crops represent a potential unconventional feed ingredient that could help in exploiting the circular economy in livestock production, thereby improving sustainability.