Partially defatted black soldier fly larva meal inclusion in piglet diets: effects on the growth performance, nutrient digestibility, blood profile, gut morphology and histological features

Insect as feed ingredients for pigs

Among edible insects, black soldier fly (Hermetia illucens), yellow mealworm (Tenebrio molitor), and common housefly (Musca domestica) have been considered as an alternative protein source for pigs. Because they are easy to breed and grow in the organic wastes, and they have well-balanced nutritional value as a protein source for pigs. The black soldier fly larvae and mealworm could replace the fish meal in the diets for weaned pigs without adverse effects on growth performance and nutrient digestibility. Black soldier fly could also be included in the finishing pig's diet without any negative effects on the growth performance and pork quality of the market pigs. Insect products showed a greater standardized ileal digestibility value of amino acids than conventional animal proteins in growing pigs. Due to the limited amount of insect products used for pig feeding study, most previous pig studies have been conducted in weaned pigs. Thus, further study is needed about the optimal inclusion level of insect products in every phase diet from weaned pigs to sows. The use of insect products in swine diets has some challenges in terms of cost, supply, and safety. Lastly, intrinsic differences among insect species, processing method, and feeding phase should be taken into consideration for the use of insect products in the swine diets.

Citric Acid Promoting B Lymphocyte Differentiation and Anti-epithelial Cells Apoptosis Mediate the Protective Effects of Hermetia illucens Feed in ETEC Induced Piglets Diarrhea

Newborn piglets are prone to diarrhea after weaning as a result of changes in their environment and feed. Enterotoxigenic Escherichia coli (ETEC) K88 strain is a typical pathogen that causes diarrhea in such stage of piglets. Hermetia illucens larvae are widely used in livestock and poultry production because of their high nutritional value and immunoregulatory effects. This study aimed to evaluate the protective effects of H. illucens feed in protecting against ETEC induced diarrhea in piglets and to unravel the mechanisms of immune modulation and intestinal barrier maintenance. The results showed that after ETEC infection, citric acid in the serum of the groups fed on H. illucens larvae increased significantly, which stimulated macrophages to secrete cytokines that promote B lymphocyte differentiation, ultimately increasing the production of IgA and IgG in serum. Concomitantly, citric acid also had a positive effect on the intestinal barrier damaged due to ETEC infection by inhibiting the production of inflammatory cytokines, reducing the Bcl-2/Bax ratio, and promoting the expression of tight junction proteins. Correlation analysis showed that the increase of citric acid levels might be related to Massilia. Thus, citric acid derived from H. illucens larvae can improve the immune performance of weaned piglets and reduce ETEC-induced damage to the intestinal barrier in weaned piglets.

Dietary Hermetia illucens Larvae Replacement Alleviates Diarrhea and Improves Intestinal Barrier Function in Weaned Piglets Challenged With Enterotoxigenic Escherichia coli K88

A high-quality protein substitute, Hermetia illucens (black soldier fly) larvae powder, is rich in protein and often used in animal feed. This study aimed to investigate the feasibility and optimal ratio of replacing fish meal with H. illucens larvae in weaned piglets and to demonstrate the effects on piglets' growth performance, intestinal microflora and immune performance. Forty-eight female weaned piglets were randomly classified into three groups. Each group consisted of eight pens (replicates), with two piglets per pen. Three groups containing different proportions of H. illucens larvae (0, 4, and 8%) were referred to as C, HI4, and HI8. We first designed a 28-day feeding experiment to detect growth performance; after that, the piglets were induced with oral gavage of enterotoxigenic Escherichia coli K88 (ETEC K88) and recording diarrhea on day 29 of the experiment. Samples were taken on the 32nd day to detect the effect of H. illucens larvae on the immune performance of the weaned piglets. H. illucens larvae replacement did not cause any obvious change in the growth performance nether in HI4 nor in HI8 of weaned piglets with 28 d feeding stage. H. illucens larvae could improve the intestinal health of weaned piglets by increasing the content of Lactobacillus and reducing the content of Streptococcus. Compared with C+K88 group, the diarrhea rate was attenuated for the H. illucens supplemented group. The integrity of ileum villi in HI4+K88 and HI8+K88 groups was better than that in C+K88 group, and the villi in C+K88 group were severely damaged. The expression of IL-10, Occludin and Claudin-3 in the intestinal mucosa of the HI4+K88 group and HI8+K88 group were significantly increased (P < 0.05), and the expression of TNF-α was significantly decreased (P < 0.05) compared with the C+K88 group. The results of immunoblotting also validated that the same ETEC K88 treatment of weaned piglets enhanced the expression of tight junction protein in the intestinal mucosa of the H. illucens addition group. ETEC-induced diarrhea will be reduced by the diet of weaned piglets containing H. illucens larvae, ameliorating the immune performance of piglets. Our results indicates that the optimal dosage of H. illucens replacement in weaned piglets is 4%.

Partial and Total Replacement of Soybean Meal with Full-Fat Black Soldier Fly (Hermetia illucens L.) Larvae Meal in Broiler Chicken Diets: Impact on Growth Performance, Carcass Quality and Meat Quality

The aim of this study was to compare selected growth performance parameters and slaughter characteristics in broiler chickens fed diets with a different content of full-fat Hermetia illucens L. (HI) larvae meal. The experiment was performed on 384 male broiler chickens (Ross 308) reared to 42 d of age and assigned to four dietary treatments (HI0-control diet and diets where soybean meal protein (SBM) was replaced with HI protein in 50%, 75% and 100%, respectively). The final body weights of chickens were as follows: 3010.0 g (HI0), 2650.0 g (HI50), 2590.0 g (HI75) and 2375.0 g (H100, p < 0.05). The carcasses of chickens from the experimental groups contained less meat and more abdominal fat. The feed conversion ratio for the entire experimental period was similar in groups HI0, HI50 and HI75 and more desirable than in group HI100 (p < 0.05). The meat of broiler chickens from groups HI75 and HI100 was characterized by significantly (p < 0.05) lower juiciness and taste intensity than the meat of birds from groups HI0 and HI50. The replacement of SBM protein with full-fat HI larvae meal in broiler diets exceeding 50% significantly compromised the growth performance of birds and the carcass and meat quality.

Insects as Novel Ruminant Feed and a Potential Mitigation Strategy for Methane Emissions

Simple Summary

In the last decade, there has been a growing interest in using edible insects as animal feed due to their high nutritive value and environmental advantages over the conventional livestock feeds. Insects have been used in the diets of some animals (poultry, fish, and swine) however, their evaluation in ruminants is still limited. The current in vitro study evaluated the usage of four different kinds of edible insects to partially substitute soybean meal as an example to the conventional high-quality expensive protein sources in ruminants’ diets. This study showed that the evaluated insects had high protein and fat contents. Substitution of 25% of soybean meal with the tested insects in a ruminant diet had no adverse effect on rumen fermentation profile or nutrient digestibility. Moreover, the inclusion of some species in the diet led to a reduction of the methane production up to 16–18% which is an additional environmental benefit. The findings of this study are encouraging for further work in this promising area to improve the sustainability of livestock industry.

Abstract

This study is the first to evaluate the chemical composition and impacts of four different edible insects, Acheta domesticus (A.d), Brachytrupes portentosus (B.p), Gryllus bimaculatus (G.b), and Bombyx mori (B.m), on the digestibility, rumen fermentation, and methane production when used as a substitute for 25% of the soybean meal (SBM) in a ruminant diet through in vitro incubation. The dietary treatments were 100% grass hay, 60% grass hay + 40% SBM, 60% grass hay + 30% SBM + 10% A.d, 60% grass hay + 30% SBM + 10% B.p, 60% grass hay + 30% SBM + 10% G.b, and 60% grass hay + 30% SBM + 10% B.m. The experiment was conducted as a short-term batch culture for 24 h at 39 °C, and the incubation was repeated in 3 consecutive runs. Chemical analysis of the insects showed that they were rich in fat (14–26%) with a high proportion of unsaturated fatty acids (60–70%). Additionally, the insects were rich in protein (48–61%) containing all essential amino acids and the amino acid profiles of the insects were almost the same as that of SBM. The inclusion of insects did not affect nutrient digestibility or the production of volatile fatty acids but did increase the production of ammonia-nitrogen. The addition of G.b and B.m led to decrease in methane production by up to 18% and 16%, respectively. These results reveal that substitution of 25% SBM in the diet with the tested insects had no negative impacts, and their potential to reduce methane production is an environmental benefit.

Local intestinal microbiota response and systemic effects of feeding black soldier fly larvae to replace soybean meal in growing pigs

Black soldier fly (Hermetia illucens; BSF) larvae as dietary protein source have the ability to deliver nutrients and could possess functional properties that positively support animal productivity and health. More knowledge, however, is needed to assess the impact of feeding a BSF based diet on gut and animal health. Sixteen post-weaned male pigs were randomly assigned to two groups and fed for three weeks with iso-caloric and iso-proteinaceous experimental diets prepared with either soybean meal (SBM) as reference protein source or with BSF as single source of dietary protein. At the end of the trial, the pigs were sacrificed to collect relevant digesta, gut tissue and blood samples to study changes induced by the dietary treatments using ~ omics based analyses. Inclusion of BSF in the diet supports the development of the intestinal microbiome that could positively influence intestinal health. By amine metabolite analysis, we identified two metabolites i.e. sarcosine and methionine sulfoxide, in plasma that serve as markers for the ingestion of insect based ingredients. BSF seems to possess functional properties indicated by the appearance of alpha-aminobutyric acid and taurine in blood plasma of pigs that are known to induce health beneficial effects.

Effect of Tenebrio molitor larvae meal on the antioxidant status and stress response pathways in tissues of growing pigs

Insect meal (IM) produced from edible insects, such as Tenebrio molitor, has been recognised as a potentially suitable protein component in feeding rations for monogastric livestock. While several studies with broilers have shown that animal´s health is not negatively affected by IM, less is known with regard to the influence of IM on metabolism of pigs. The present study investigates whether IM from Tenebrio molitor larvae causes oxidative stress and activates oxidative stress-sensitive signalling pathways in key metabolic tissues of pigs. To address this question, male 5-week-old crossbred pigs were randomly assigned to three groups of 10 pigs each and fed nutrient-adequate, isonitrogenous diets either without (CON) or with 5% IM or 10% IM from Tenebrio molitor larvae for 4 weeks. Concentrations of thiobarbituric acid reactive substances, tocopherols and glutathione in liver, gastrocnemius muscle and/or plasma did not differ between groups. Activities of the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD) in the liver and of GPX and SOD in gastrocnemius muscle were not different between groups, whereas the activity of CAT in skeletal muscle was increased in the two IM-fed groups compared to group CON (p < 0.05). The mRNA levels of most of the target genes of oxidative stress-sensitive signalling pathways, such as nuclear factor-κB, nuclear factor erythroid 2-related factor 2 and endoplasmic reticulum stress-induced unfolded protein response, in liver and gastrocnemius muscle did not differ between the three groups. The present study shows that feeding a diet containing adequate levels of antioxidants, such as vitamin E and selenium, and Tenebrio molitor larvae meal as a protein component neither causes oxidative stress nor activates oxidative stress-sensitive signalling pathways in key metabolic tissues of growing pigs. Based on these observations, IM from Tenebrio molitor larvae can be regarded as a safe source of protein in growing pigs.

The Influence of Food Waste Rearing Substrates on Black Soldier Fly Larvae Protein Composition: A Systematic Review

Simple Summary

The Black Soldier Fly (BSF) is a viable option for countering the environment detriments caused by food waste and can provide a sustainable protein source to feed the growing global population. This systematic literature review investigated the impacts of various foodstuffs and food waste rearing substrates on the protein and amino acid composition of BSF larvae. From the 23 articles included, BSF larvae fed ‘Fish waste Sardinella aurita’ for two days produced the highest total protein content at 78.8% and rearing substrates ‘Fruit and vegetables’ reported the lowest protein content at 12.9% of the BSF total mass. However, variation in rearing and analytical methodologies between each study potential undermines the extent to which the rearing substrates may have influenced the overall protein content of BSF larvae, their application in nutrition is still in its infancy.

Abstract

The Black Soldier Fly (BSF) offers the potential to address two global challenges; the environmental detriments of food waste and the rising demand for protein. Food waste digested by BSF larvae can be converted into biomass, which may then be utilized for the development of value-added products including new food sources for human and animal consumption. A systematic literature search was conducted to identify studies investigating the influence of food waste rearing substrates on BSF larvae protein composition. Of 1712 articles identified, 23 articles were selected for inclusion. Based on the results of this review, BSF larvae reared on ‘Fish waste Sardinella aurita’ for two days reported the highest total protein content at 78.8% and BSF larvae reared on various formulations of ‘Fruit and vegetable’ reported the lowest protein content at 12.9%. This review is the first to examine the influence of food waste on the protein composition of BSF larvae. Major differences in larval rearing conditions and methods utilized to perform nutritional analyses, potentially influenced the reported protein composition of the BSF larvae. While this review has highlighted the role BSF larvae in food waste management and alternative protein development, their application in nutrition is still in its infancy.

Gut Health in Veterinary Medicine: A Bibliometric Analysis of the Literature

Gut health is a recent relevant research topic in veterinary medicine and it has been shown to be associated with better zootechnical performances and animal welfare. A bibliometric analysis was performed to explore publication trends, dynamics and possible knowledge gaps in this field in the last twenty years (2000-2020). The database Web of Science was searched and the results were analyzed by the R package Bibliometrix. A total of 1696 documents were retrieved in the evaluated period, showing a constant annual growth in the number of publications of 22.4%. These articles focused mainly on pigs (34.8%), poultry (chicken, duck, turkey and quail-33.9%) and aquaculture (fishes, crustaceans and frog-15.0%) while a scarce number was found on felines, cows, horses, rodents, goats and sheep. China was the most productive country (24.7%) followed by the USA (17.2%) and Canada (5.7%). Keyword's analysis showed that the main research lines aimed to explore animal nutrition, prevention of inflammatory diseases and microbiota composition. This study shows a comprehensive bibliometric analysis of the evolution of veterinary gut health research that will help to drive future investigations on this topic.

Antimicrobial Peptides from Black Soldier Fly (Hermetia illucens) as Potential Antimicrobial Factors Representing an Alternative to Antibiotics in Livestock Farming

Functional antimicrobial peptides (AMPs) are an important class of effector molecules of innate host immune defense against pathogen invasion. Inability of microorganisms to develop resistance against the majority of AMPs has made them alternatives to antibiotics, contributing to the development of a new generation of antimicrobials. Due to extensive biodiversity, insects are one of the most abundant sources of novel AMPs. Notably, black soldier fly insect (BSF; Hermetia illucens (Diptera: Stratiomyidae)) feeds on decaying substrates and displays a supernormal capacity to survive under adverse conditions in the presence of abundant microorganisms, therefore, BSF is one of the most promising sources for identification of AMPs. However, discovery, functional investigation, and drug development to replace antibiotics with AMPs from Hermetia illucens remain in a preliminary stage. In this review, we provide general information on currently verified AMPs of Hermetia illucens, describe their potential medical value, discuss the mechanism of their synthesis and interactions, and consider the development of bacterial resistance to AMPs in comparison with antibiotics, aiming to provide a candidate for substitution of antibiotics in livestock farming or, to some extent, for blocking the horizontal transfer of resistance genes in the environment, which is beneficial to human and animal welfare.

In vivo and in vitro Digestibility of an Extruded Complete Dog Food Containing Black Soldier Fly (Hermetia illucens) Larvae Meal as Protein Source

Growing attention is being directed toward insects as a novel and sustainable source of protein for pet food. The aim of the study was to evaluate nutrient digestibility of a diet containing black soldier fly larvae as its main protein source. Moreover, the purpose of the study was to compare the traditional in vivo total collection method with the in vivo marker method and in vitro digestibility method. Two isonitrogenous and isoenergetic dry diets containing either venison meal (CTRL diet) or black soldier fly larvae meal (BSF diet) as their primary sources of proteins were fed to six adult dogs, according to a Latin square design. The digestibility of nutrients was determined using both in vivo ("total collection" and "internal marker" approaches) and in vitro methods. The two diets showed similar nutrient digestibility values for dry matter, organic matter, ether extract, ash, and phosphorus. However, a statistical trend (p = 0.066) was observed indicating greater protein digestibility in the BSF diet compared with the CTRL diet. Calcium digestibility was higher in the BSF diet compared with the CTRL diet (p = 0.018). On the contrary, fiber digestibility was lower in the insect-based diet compared with the venison diet (p < 0.001). There was no difference between total collection and internal marker methods in the assessment of in vivo digestibility for any of the nutrients considered. The in vitro digestibility values for dry matter, organic matter, and crude protein, as well as the estimated in vivo digestibility of organic matter and crude protein by the means of the predictive equation, were aligned with the in vivo results, although in vitro estimations were consistently higher compared with those obtained by in vivo analysis. Digestibility analysis of a dog food containing insect meal as the sole source of protein (36.5% inclusion) showed promising results in terms of it presenting similar values as a meat-based diet, indicating its suitability as a sustainable protein source for pet food. Moreover, the study showed that both the in vivo marker method and the in vitro method could be possible alternatives to the traditional total collection method in digestibility trials.

Global population genetic structure and demographic trajectories of the black soldier fly, Hermetia illucens

BACKGROUND

The black soldier fly (Hermetia illucens) is the most promising insect candidate for nutrient-recycling through bioconversion of organic waste into biomass, thereby improving sustainability of protein supplies for animal feed and facilitating transition to a circular economy. Contrary to conventional livestock, genetic resources of farmed insects remain poorly characterised. We present the first comprehensive population genetic characterisation of H. illucens. Based on 15 novel microsatellite markers, we genotyped and analysed 2862 individuals from 150 wild and captive populations originating from 57 countries on seven subcontinents.

RESULTS

We identified 16 well-distinguished genetic clusters indicating substantial global population structure. The data revealed genetic hotspots in central South America and successive northwards range expansions within the indigenous ranges of the Americas. Colonisations and naturalisations of largely unique genetic profiles occurred on all non-native continents, either preceded by demographically independent founder events from various single sources or involving admixture scenarios. A decisive primarily admixed Polynesian bridgehead population serially colonised the entire Australasian region and its secondarily admixed descendants successively mediated invasions into Africa and Europe. Conversely, captive populations from several continents traced back to a single North American origin and exhibit considerably reduced genetic diversity, although some farmed strains carry distinct genetic signatures. We highlight genetic footprints characteristic of progressing domestication due to increasing socio-economic importance of H. illucens, and ongoing introgression between domesticated strains globally traded for large-scale farming and wild populations in some regions.

CONCLUSIONS

We document the dynamic population genetic history of a cosmopolitan dipteran of South American origin shaped by striking geographic patterns. These reflect both ancient dispersal routes, and stochastic and heterogeneous anthropogenic introductions during the last century leading to pronounced diversification of worldwide structure of H. illucens. Upon the recent advent of its agronomic commercialisation, however, current human-mediated translocations of the black soldier fly largely involve genetically highly uniform domesticated strains, which meanwhile threaten the genetic integrity of differentiated unique local resources through introgression. Our in-depth reconstruction of the contemporary and historical demographic trajectories of H. illucens emphasises benchmarking potential for applied future research on this emerging model of the prospering insect-livestock sector.

Using black soldier fly larvae reared on fruits and vegetables waste as a sustainable dietary source of provitamin a carotenoids

We showed that black soldier fly larvae reared on fruits and vegetables rich in provitamin A carotenoids can accumulate significant amounts of these vitamin A precursors. Using a simulated gastro-intestinal digestion model, we demonstrated that α- and β-carotene from the larvae are as bioaccessible as from the fruits and vegetables they were reared on. We calculated that provitamin A carotenoid-rich larvae have the capacity to provide more vitamin A than fruits and vegetables rich in these molecules. Remarkably, the incorporation of usual quantities of these larvae in feed could cover the needs of several production animals for this vitamin. Thus, our findings suggest that rearing black soldier fly larvae on by-products or waste rich in provitamin A carotenoids could be a sustainable strategy to recycle a fraction of vitamin A back into the food chain and could represent a new approach to fight against vitamin A deficiency.

The effects of partially replacing animal protein sources with full fat black soldier fly larvae meal (Hermetia illucens) in nursery diets on growth performance, gut morphology, and immune response of pigs

One hundred and forty-four newly weaned pigs (6.74 ± 0.23 kg initial BW; 21 d of age) were used to determine the effect of partially replacing animal protein sources with black solider fly larvae meal (BSFLM) in nursery diets on growth performance, gut morphology, and immune response. After weaning, pigs were placed in 24 pens (six pigs per pen) and pens were randomly assigned to one of four dietary treatments (study d 0; n = 6), which were fed over three phases (phases I, II, and III were fed for 7, 14, and 21 d, respectively). Two nursery diets were formulated with 25% (LowFF) and 50% (HighFF) of the animal protein sources replaced by full fat BSFLM. Conventional nursery diets including animal protein sources without (CON−) and with antibiotics (220 mg Aureomycin per kg of complete feed; CON+) served as controls. On d 8, two pigs per pen were sacrificed to collect organ weights and for intestinal histomorphological measurements. On d 9 and d 23, two pigs per pen were vaccinated with the novel antigen ovalbumin (OVA). Blood samples were collected on d 9, d 23, and d 38 to assess concentrations of plasma haptoglobin and OVA-specific immunoglobulins G (IgG) and IgG1. On d 38, the same two pigs per pen underwent a dermal hypersensitivity test and skin-fold thickness was measured at 0, 6, 24, and 48 h postintradermal injection with OVA. Pigs fed the CON- had greater ADFI and lower G:F in phase II vs. those fed CON+ and HighFF diets (P < 0.05 and P < 0.05); intermediate ADFI was observed for pigs fed the LowFF diet. Overall in the nursery period, ADG (496 ± 13 g), ADFI (743 ± 23 g), G:F, and final BW (27.61 ± 0.66 kg) were not different among dietary treatments. There were no differences in organ weights, jejunal or ileal villus heights, or crypt depths among dietary treatments. There were no differences in OVA-specific IgG, IgG1, or plasma haptoglobin among dietary treatments at any of the blood sampling times. Although not different, pigs fed the LowFF, HighFF, and CON+ diets had respectively 2.0×, 1.7×, and 1.4× greater dermal hypersensitivity response to OVA versus those fed CON−. Both inclusion levels of BSFLM in nursery diets supported growth performance, gut morphology, and indices of immune function not different from the CON+, which suggest that full fat BSFLM can replace at least 50% of animal protein sources in nursery diets of pigs without any deleterious effects on pig growth.

Dietary seaweed-derived polysaccharides improve growth performance of weaned pigs through maintaining intestinal barrier function and modulating gut microbial populations

Background

Seaweed-derived polysaccharides (SDP) represent an attractive source of prebiotic nutraceuticals for the food and animal husbandry industry. However, the mechanism by which SDP from Enteromorpha mediates pig growth are not fully understood. This study aimed to investigate how SDP supplementation influences the growth performance and intestinal health in weaned pigs.

Results

In Exp. 1, 240 weaned pigs were randomly assigned to four dietary treatments and fed with a basal diet or a basal diet containing 200, 400 or 800 mg/kg SDP, respectively, in a 21-day trial. Pigs on the 400 or 800 mg/kg SDP-supplemented group had greater ADG and lower F/G ratio than those on the control group (P<0.05). In Exp. 2, 20 male weaned pigs were randomly assigned to two treatments and fed with a basal diet (CON group) or a basal diet supplemented with 400 mg/kg SDP (the optimum does from Exp. 1), in a 21-day trial. Pigs fed the SDP diet had greater ADG, the concentrations of serum IL-6 and TNF-α and the activities of glutathione peroxidase, superoxide dismutase and catalase (P<0.05), and lower F/G, diarrhea rate, as well as serum D-lactate concentrations and diamine oxidase activity (P<0.05). Moreover, dietary SDP supplementation enhanced secretory immunoglobulin A content, villus height and villous height: crypt depth ratio in small intestine, as well as the lactase and maltase activities in jejunum mucosa (P<0.05). SDP supplementation elevated the mRNA levels of inflammatory response-related genes (IL-6, TNF-α, TLR4, TLR6 and MyD88), and the mRNA and protein levels of ZO-1, claudin-1 and occludin in jejunum mucosa (P<0.05). Importantly, SDP not only increased the Lactobacillus population but also reduced the Escherichia coli population in cecum (P<0.05). Furthermore, SDP increased acetic acid and butyric acid concentrations in cecum (P<0.05).

Conclusions

These results not only suggest a beneficial effect of SDP on growth performance and intestinal barrier functions, but also offer potential mechanisms behind SDP-facilitated intestinal health in weaned pigs.

Digestibility and safety of dry black soldier fly larvae meal and black soldier fly larvae oil in dogs

Two trials were conducted to assess the acceptance, safety and digestibility of diets containing various inclusion levels of partially defatted black soldier fly (Hermetia illucens) larvae (BSFL) meal and BSFL oil by dogs. In trial 1, 5 extruded diets were evaluated for acceptance in adult Beagle dogs (n = 20; 10 male, 10 female) during a 48-hr period. Diets contained graded levels of BSFL meal (5.0%, 10.0%, and 20.0%), or graded levels of BSFL oil (2.5% and 5.0%), and all diets were well accepted. Thus, a digestibility trial (trial 2) was run with 56 adult dogs (16 male, 40 female) allocated into 7 dietary treatments; dogs were offered an extruded control diet containing no BSFL meal or oil, or extruded diets where BSFL meal partially replaced poultry by-product meal and corn meal at dietary levels of 5%, 10%, or 20% inclusion, or diets with BSFL oil partially replacing poultry fat at a 1:1 ratio at levels of 1%, 2.5%, or 5% inclusion. The treatment diets were fed for 28 d, during which time dogs were monitored for health (via physical examinations, clinical observations, and blood chemistry and hematology) and ingredient evaluation (via body weight, feed consumption, stool observation, and fecal nutrient apparent total tract digestibility). There were no significant differences in body weight or food consumption between treatment groups (P > 0.05) and daily observations indicated that the general health of the animals was maintained throughout the study. Stool quality was maintained at 3.2 to 3.4 (on a 5-point scale with a score of 1 being watery diarrhea and a score of 5 being hard, dry, and crumbly) per treatment group over the fecal observation period (days 22 to 27), indicating a well formed, sticky stool. All group mean hematology and blood chemistry parameters remained within normal limits for dogs. Apparent total tract digestibility of dry matter, protein, fat, and calories was not affected by treatment (P > 0.05). In general, amino acid digestibility was not impacted by treatment although some minor changes were observed. Apparent total tract digestibility was high for all nutrients examined. Overall, it was concluded that BSFL meal and BSFL oil are well tolerated by dogs and their consumption results in no impact to physiology that would be concerning. Based on these data, BSFL meal and oil did not affect general health and could be included safely in dog diets.

The Potential of Locally-Sourced European Protein Sources for Organic Monogastric Production: A Review of Forage Crop Extracts, Seaweed, Starfish, Mussel, and Insects

Organic monogastric agriculture is challenged because of a limited availability of regional and organic protein-rich ingredients to fulfill the amino acid requirements. The development of novel feed ingredients is therefore essential. The use of starfish (Asterias rubens), mussel (Mytilus edilus), insect, green and brown seaweed, and forage crop extracts exhibits different approaches to increase protein availability in a sustainable manner through improving the protein quality of existing ingredients, better use of under- or unutilized material, or development of circular bioeconomy. This review assessed limitations and opportunities of producing, processing, and using these novel ingredients in feed. The use of non-renewable resources and the effect on the environment of production and processing the feed ingredients are described. Protein concentration and amino acid quality of the feed ingredients are evaluated to understand their substitution potential compared with protein-rich soya bean and fishmeal. Feedstuffs’ effect on digestibility and animal performance is summarized. With the exception of seaweed, all novel ingredients show potential to partly substitute fishmeal or soya bean fulfilling part of the protein requirement in organic monogastric production. However, improvements during production and processing can be made to enhance protein quality, sustainability of the novel ingredients, and nutrient utilization of novel feed ingredients.

Piglets can secrete acidic mammalian chitinase from the pre weaning stage

Fishmeal substitutes (such as insect-based feeds) in pig diets can promote sustainable pork production. Insect powders contain chitin, a nitrogen-containing indigestible material, and pigs must have the capacity to secrete chitin-degrading enzymes to benefit from these diets. The chitin-degrading enzyme (acidic mammalian chitinase; AMCase) and its gene expression have been detected in the stomach tissue of approximately 6-month-old fattening pigs; however, it remains unclear from which stage chitin-degrading enzymes are secreted. In the present study, the stomach tissue of piglets was collected from the suckling stage (14 d old) to 56 d to evaluate chitin-degrading enzymes and associated gene expression. AMCase mRNA and protein expression was detected in the stomach tissue of all piglets from days 14 to 56. AMCase secretion might increase with the increase in stomach tissue weight as piglets grow. Insect powders can therefore be used in the diets of pre-weaning piglets. The gastric AMCase level was approximately 30% that of fattening pigs. The appropriate inclusion of insect meals in the diets of pigs at different growth stages still needs to be determined.

Insects: A Potential Source of Protein and Other Nutrients for Feed and Food

Sustainable production of healthy food for a growing global population, in the face of the uncertainties of climate change, represents a major challenge for the coming decade. Livestock provide food with high nutritional value but are frequently fed on human-edible crops and are associated with significant production of greenhouse gases. Recent years have seen increasing interest in the farming of insects as a sustainable source of human food, or as a replacement of ingredients such as soya or fishmeal in the feeds of terrestrial livestock or fish. This review provides an overview of insect physiology and growth regulation, considers the requirements for insect farming and mass production, and summarizes the nutritional value of the 10 most commonly studied insect species, before reviewing the literature on the use of insects as feed and food. We highlight the challenges required to develop a sustainable, safe, and affordable insect farming industry.

Rethinking organic wastes bioconversion: Evaluating the potential of the black soldier fly (Hermetia illucens (L.)) (Diptera: Stratiomyidae) (BSF)

Population growth and unprecedented economic growth and urbanization, especially in low- and middle-income countries, coupled with extreme weather patterns, the high-environmental footprint of agricultural practices, and disposal-oriented waste management practices, require significant changes in the ways we produce food, feed and fuel, and manage enormous amounts of organic wastes. Farming insects such as the black soldier fly (BSF) (Hermetia illucens) on diverse organic wastes provides an opportunity for producing nutrient-rich animal feed, fuel, organic fertilizer, and biobased products with concurrent valorization of wastes. Inclusion of BSF larvae/pupae in the diets of poultry, fish, and swine has shown promise as a potential substitute of conventional feed ingredients such as soybean meal and fish meal. Moreover, the bioactive compounds such as antimicrobial peptides, medium chain fatty acids, and chitin and its derivatives present in BSF larvae/pupae, could also add values to the animal diets. However, to realize the full potential of BSF-based biorefining, more research and development efforts are necessary for scaling up the production and processing of BSF biomass using more mechanized and automated systems. More studies are also needed to ensure the safety of the BSF biomass grown on various organic wastes for animal feed (also food) and legalizing the feed application of BSF biomass to wider categories of animals. This critical review presents the current status of the BSF technology, identifies the research gaps, highlights the challenges towards industrial scale production, and provides future perspectives.

Partially Defatted Hermetia illucens Larva Meal in Diet of Eurasian Perch (Perca fluviatilis) Juveniles

Simple Summary

The replacement of fishmeal by insect meal is a promising strategy to obtain more sustainable fish feeds, a major goal in aquaculture. Black soldier fly Hermetia illucens larva meal has a high crude protein and fat content, essential for omnivorous and carnivorous fish. We used partially defatted H. illucens larva meal as a substitute for 20%, 40% and 60% of the fishmeal in standard diets for Eurasian perch and measured its effect on growth performance, feed utilization, body indices, fish body composition and blood indices. We found no significant differences in survival, size heterogeneity, hematology indices; or in whole-body dry matter, crude protein and ether extract content. The 60% inclusion reduced final body weight, specific growth rate, feeding rate, protein efficiency ratio, condition factor and hepatosomatic index. The fish-in-fish-out index decreased proportionally with increased H. illucens meal inclusion. Partially defatted H. illucens larva meal seems to be a promising alternative to fishmeal for Eurasian perch nutrition at moderate inclusion level.

Abstract

Insect meal is gaining increased attention in aquafeed formulations due to high protein content and an essential amino acid profile similar to that of fishmeal. To investigate insect meal in feed for European perch Perca fluviatilis, a promising candidate for European intensive culture, we replaced standard fishmeal with partially defatted black soldier fly Hermetia illucens larva meal at rates of 0%, 20%, 40% and 60% (groups CON, H20, H40 and H60, respectively) and compared growth performance, somatic indices, hematological parameters, whole-body proximate composition and occurrence of spleen lipidosis. In addition, we assessed the economic and environmental sustainability of the tested feeds by calculating economic conversion ratio (ECR) and economic profit index (EPI). The tested groups did not differ in survival rate. Significant differences were documented in final body weight and specific growth rate, with the highest values in CON, H20 and H40. The proximate composition of fish whole-body at the end of the experiment did not differ in dry matter, crude protein or ether extract, while organic matter, ash and gross energy composition showed significant differences. The fatty acid content and n-3/n-6 ratio showed a decreasing trend with increasing H. illucens larva meal inclusion. No differences were found in hematological parameters among tested groups. The H. illucens larva meal inclusion significantly affected ECR and EPI, even at 20% inclusion level the cost of diets did not differ from the control fish meal based diet. Results suggested that 40% inclusion of H. illucens larva meal can be used successfully in standard diets for perch.

Standardized ileal digestible amino acids and net energy contents in full fat and defatted black soldier fly larvae meals (Hermetia illucens) fed to growing pigs

Two experiments were conducted to determine standardized ileal digestibility (SID) of amino acids (AA; Exp. 1) and net energy (Exp. 2) in two black soldier fly larvae meal (BSFLM) samples [full fat (FF; 42.5% crude protein (CP), as-fed) and defatted (DF; 40.8% CP; as-fed)] for growing pigs. Two cornstarch-based diets were formulated with FF and DF BSFLM as the sole sources of AA. A nitrogen-free diet was also used, and the corn starch:sucrose:oil ratio was kept constant among diets to calculate digestible energy (DE) by difference method. In each experiment, pigs were fed 2.8 × estimated maintenance energy requirement. In Exp. 1, eight ileal-cannulated barrows (25.1 ± 0.41 kg initial body weight) were used in a replicated 2 × 2 Latin square design (n = 8). In each period, pigs were adapted to diets for 5 d followed by 2 d of continuous ileal digesta collection for 8 h. The SID of AA were calculated using basal endogenous losses for pigs fed a nitrogen-free diet. In Exp. 2, eight barrows [23.4 ± 0.54 kg initial body weight (BW)] were used in a partially replicated Latin square design (n = 8). In each period, pigs were adapted to diets for 7 d, followed by 5 d of total urine collection and fecal grab sampling. The SID of CP (80.6 ± 1.1%) and Lys (88.0 ± 1.4%) were not different between FF and DF BSFLM. The SID of Arg, Val, Ala, and Pro tended to be less, and the SID of Met tended to be greater for the FF versus the DF BSFLM (P = 0.034, 0.090, 0.053, 0.065, 0.074, respectively). Digestible energy (4,927 vs. 3,941 ± 75 kcal/kg), metabolizable energy (4,569 vs. 3,396 ± 102 kcal/kg), and predicted net energy (3,477 vs. 2,640 ± 30 kcal/kg, using equations from Noblet; 3,479 vs. 2,287 ± 28 kcal/kg, using equations from Blok, respectively) were greater for the FF versus the DF BSFLM (P < 0.05). The apparent total tract digestibility of neutral detergent fiber and acid detergent fiber were greater for the FF versus the DF BSFLM (P ≤ 0.05). Both FF and DF BSFLM had high SID for most AA; however, FF BSFLM was a better source of net energy for growing pigs. Therefore, both FF and DF BSFLM could be used as protein alternatives in growing pig diets.

Effects of dietary Hermetia illucens meal inclusion on cecal microbiota and small intestinal mucin dynamics and infiltration with immune cells of weaned piglets

Background

The constant interaction between diet and intestinal barrier has a crucial role in determining gut health in pigs. Hermetia illucens (HI) meal (that represents a promising, alternative feed ingredient for production animals) has recently been demonstrated to influence colonic microbiota, bacterial metabolite profile and mucosal immune status of pigs, but no data about modulation of gut mucin dynamics are currently available. The present study evaluated the effects of dietary HI meal inclusion on the small intestinal mucin composition of piglets, as well as providing insights into the cecal microbiota and the mucosal infiltration with immune cells.

Results

A total of 48 weaned piglets were randomly allotted to 3 dietary treatments (control diet [C] and 5% or 10% HI meal inclusion [HI5 and HI10], with 4 replicate boxes/treatment and 4 animals/box) and slaughtered after 61 days of trial (3 animals/box, 12 piglets/diet). The cecal microbiota assessment by 16S rRNA amplicon based sequencing showed higher beta diversity in the piglets fed the HI-based diets than the C (P <  0.001). Furthermore, the HI-fed animals showed increased abundance of Blautia, Chlamydia, Coprococcus, Eubacterium, Prevotella, Roseburia, unclassified members of Ruminococcaceae, Ruminococcus and Staphylococcus when compared to the C group (FDR <  0.05). The gut of the piglets fed the HI-based diets showed greater neutral mucin percentage than the C (P <  0.05), with the intestinal neutral mucins of the HI-fed animals being also higher than the sialomucins and the sulfomucins found in the gut of the C group (P <  0.05). Furthermore, the piglets fed the HI-based diets displayed lower histological scores in the jejunum than the other gut segments (ileum [HI5] or ileum and duodenum [HI10], P <  0.05).

Conclusions

Dietary HI meal utilization positively influenced the cecal microbiota and the small intestinal mucin dynamics of the piglets in terms of selection of potentially beneficial bacteria and preservation of mature mucin secretory architecture, without determining the development of gut inflammation. These findings further confirm the suitability of including insect meal in swine diets.

The produced mealworm meal through organic wastes as a sustainable protein source for weanling pigs

This study was designed to evaluate the influence of dietary supplementation of Tenebrio molitor larvae (TM) as an alternative source of protein to fish meal on growth response, retention of nutrient, hematological factors, immune system, and intestinal integrity in weaned pigs. A total of 180 weanling pigs (initial bodyweight of 6.27 ± 0.15 kg; 21 d) were distributed based on the bodyweight between 3 treatments with 6 replicates in each treatment including 10 piglets per replicate. The diets corresponding to treatments consisted of a fish meal diet (CON), a fish meal-dried mealworm diet (TM1, 50% replacement of fish meal with TM meal), and a dried mealworm diet (TM2, 100% replacement of fish meal with TM meal). This study was performed in two phases as phase 1 (d 0 to 14) and phase 2 (d 15 to 28). The pigs in the TM2 treatment showed a greater gain to feed ratio compared with the TM1 pigs in phase 1. Throughout the experimental period, the average daily gain (ADG) of the TM1 pigs was significantly greater than that of the TM2 treatment. The IgG concentration was increased in the TM1 and TM2 treatments compared with the CON pigs in phase 1. In conclusion, the supplementation of TM meal (50% replacement of fish meal) did not show any adverse effects in the performance of weanling pigs, however, 100% replacement of fish meal with TM meal is not recommended.

Supplementation of Sulfur-Containing Amino Acids or Essential Amino Acids Does Not Reverse the Hepatic Lipid-Lowering Effect of a Protein-Rich Insect Meal in Obese Zucker Rats

The present study tested the hypothesis that the liver lipid-lowering effect of insect meal (IM) is caused by its low methionine concentration. A total of fifty, male obese Zucker rats were randomly assigned to five groups of 10 rats each (casein (C), IM, IM + Met, IM + Cys, and IM + EAA). While group C received a diet with casein, the IM-fed groups received a diet with IM as the protein source. In groups IM + Met, IM + Cys and IM + EAA, the diets were additionally supplemented with methionine, cysteine and essential amino acids (EAA), respectively. Hepatic concentrations of triacylglycerols and cholesterol, and hepatic mRNA levels and activities of lipogenic and cholesterogenic enzymes were markedly lower in the IM-fed groups than in group C (p < 0.05). All of these parameters either did not differ across the IM-fed groups or were only slightly higher in groups IM + Met, IM + Cys and IM+EAA than in the group IM. In conclusion, the results indicate that a difference in the amino acid composition between IM and casein, a low concentration of methionine in IM and a reduced cysteine synthesis secondary to a decreased methionine availability resulting from feeding IM are not causative for the lipid-lowering effect of IM.

Preparation, antioxidant activity evaluation, and identification of antioxidant peptide from black soldier fly (Hermetia illucens L.) larvae

Black soldier fly larvae protein (BLP) was hydrolyzed using alcalase, neutrase, trypsin, and papain. The BLP hydrolysates (BLPHs) were fractionated by ultrafiltration into three peptide fractions of molecular weight (<3 kDa, 3-10 kDa and >10 kDa). Their antioxidant activities in vitro and the amino acid composition were determined. Results showed that the alcalase was more efficient in hydrolyzing the BLP into oligopeptides. BLPHs-I presented the best scavenging activity to superoxide radicals, hydroxyl radicals, DPPH, and ABTS radicals. The best scavenging activities were found in BLPHs-I containing high levels of aromatic and hydrophobic amino acids. Seventeen novel sequences with typical features of well-known antioxidant proteins were identified by LC-MS/MS. Results demonstrated that BLPHs-I possesses a great capacity as antioxidant peptides applied in functional foods. PRACTICAL APPLICATIONS: Black soldier fly larvae protein (BLP) can also be hydrolyzed to produce antioxidant peptides and their sequences were identified. It can be used in pharmaceutical products and functional foods.

Comprehensive evaluation of the metabolic effects of insect meal from Tenebrio molitor L. in growing pigs by transcriptomics, metabolomics and lipidomics

Background

The hypothesis was tested that insect meal (IM) as protein source influences intermediary metabolism of growing pigs. To test this, 30 male, 5-week-old crossbred pigs were randomly assigned to 3 groups of 10 pigs each with similar body weights (BW) and fed isonitrogenous diets either without (CON) or with 5% IM (IM5) or 10% IM (IM10) from Tenebrio molitor L. for 4 weeks and key metabolic tissues (liver, muscle, plasma) were analyzed using omics-techniques.

Results

 Most performance parameters did not differ across the groups, whereas ileal digestibilities of most amino acids were 6.7 to 15.6%-units lower in IM10 than in CON (P < 0.05). Transcriptomics of liver and skeletal muscle revealed a total of 166 and 198, respectively, transcripts differentially expressed between IM10 and CON (P < 0.05). Plasma metabolomics revealed higher concentrations of alanine, citrulline, glutamate, proline, serine, tyrosine and valine and a lower concentration of asparagine in IM10 than in CON (P < 0.05). Only one out of fourteen quantifiable amino acid metabolites, namely methionine sulfoxide (MetS), in plasma was elevated by 45% and 71% in IM5 and IM10, respectively, compared to CON (P < 0.05). Plasma concentrations of both, major carnitine/acylcarnitine species and bile acids were not different across groups. Lipidomics of liver and plasma demonstrated no differences in the concentrations of triacylglycerols, cholesterol and the main phospholipids, lysophospholipids and sphingolipids between groups. The percentages of all individual phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species in the liver showed no differences between groups, except those with 6 double bonds (PC 38:6, PC 40:6, PE 38:6, PE 40:6), which were markedly lower in IM10 than in CON (P < 0.05). In line with this, the percentage of C22:6n-3 in hepatic total lipids was lower in IM10 than in the other groups (P < 0.05).

Conclusions

Comprehensive analyzes of the transcriptome, lipidome and metabolome of key metabolic tissues indicate that partial or complete replacement of a conventional protein source by IM in the diet has only a weak impact on the intermediary metabolism of growing pigs. Thus, it is concluded that IM from Tenebrio molitor L. can be used as a dietary source of protein in pigs without causing adverse effects on metabolism.

Management of chicken manure using black soldier fly (Diptera: Stratiomyidae) larvae assisted by companion bacteria

Black soldier fly (BSF) is used for the management of organic waste, but research has hardly explored the effect of companion bacteria when chicken manure (CHM) is converted to insect biomass. In this study, we isolated nine bacterial species (FE01, FE02, FE03, FE04, FE05, FE06, FE07, FE08, FE09) from BSF eggs and one (BSF-CL) from the larval gut. These companion bacteria were inoculated into CHM along with BSF larvae (BSFL). Larval growth and manure conversion rates were determined. Results indicated that almost all bacteria individual bacteria in this study significantly promote BSFL growth. BSFL reared in manure with the species Kocuria marina (FE01), Lysinibacillus boronitolerans (FE04), Proteus mirabilis (FE08) and Bacillus subtilis (BSF-CL) had higher weight gain and manure reduction rates compared to the control. These four strains used were then examined as a poly-bacteria community experiment to determine BSFL growth and manure conversion. Manure inoculated with the poly-bacteria Group3 (FE01:FE04:FE08:BSF-CL = 4:1:1:1) and then fed to BSFL resulted in 28.6% more weight gain than the control. The greatest manure reduction rate (52.91%) was reached when companion bacteria were mixed at a ratio of 1:1:1:4. Additionally, the companion bacteria influenced the nutritional value of BSFL. Crude protein content in Group1 (FE01:FE04:FE08:BSF-CL = 1:1:1:1) was significantly larger than that of the control. Crude fat content in Group3 was significantly larger than that of the control. BSFL companion bacteria and their poly-bacteria compound improved manure conversion efficiency and nutrient accumulation in BSFL, reduced CHM quantity, increased larvae biomass, with potential economic gains in CHM management.

Effect of Dietary Replacement of Fishmeal by Insect Meal on Growth Performance, Blood Profiles and Economics of Growing Pigs in Kenya

Simple Summary

Pig keeping is an important source of income but the high cost of fishmeal (FM), which is the main protein source in animal feeds, has hindered the sector from realizing its full potential. As an alternative, we investigated the suitability of a meal derived from black soldier fly larvae (BSFLM) as a protein source. Pigs were fed different diet types: Control (no BSFLM: 0% (T0)), 25% (T25), 50% (T50), 75% (T75) and 100% (T100) replacement of FM by BSFLM. Average daily feed intake, body weight gain and feed conversion ratio were not affected by the replacement of FM by BSFLM. Red or white blood cell parameters did not differ among diets, except for neutrophil counts, which were higher at T75 and T100 compared to T0. At T25, T75 and T100, pigs had lower platelet counts compared to pigs fed T0 and T50. Dietary BSFLM inclusion did not influence blood cholesterol levels. The cost–benefit ratio and return on investment were similar across diets. Our study shows that BSFLM is a suitable and cost-effective alternative to FM in pig feeds.

Abstract

Pig production is one of the fastest growing livestock sectors. Development of this sector is hampered by rapidly increasing costs of fishmeal (FM), which is a common protein source in animal feeds. Here, we explored the potential of substituting FM with black soldier fly larval meal (BSFLM) on growth and blood parameters of pigs as well as economic aspects. At weaning, 40 hybrid pigs, i.e., crossbreeds of purebred Large White and Landrace were randomly assigned to five iso-nitrogenous and iso-energetic dietary treatments: Control (0% BSFLM and 100% FM (T0)), and FM replaced at 25% (T25), 50% (T50), 75% (T75) and 100% (T100) with BSFLM. Average daily feed intake (ADFI), average daily gain (ADG), body weight gain (BWG) and feed conversion ratio (FCR) were calculated for the whole trial. Hematological and serum biochemical parameters, the cost–benefit ratio (CBR) and return on investment (RoI) were evaluated. No significant effect of diet type was observed on feed intake and daily weight gain. Red or white blood cell indices did not differ among diets. Pigs fed T25, T75 and T100, had lower platelet counts compared to T0 and T50. Dietary inclusion of BSFLM did not affect blood total cholesterol, triglycerides, low-density lipoprotein and high-density lipoprotein. CBR and RoI were similar for the various diets. In conclusion, BSFLM is a suitable and cost-effective alternative to fishmeal in feed for growing pigs.

Quality and Consumer Acceptance of Meat from Rabbits Fed Diets in Which Soybean Oil is Replaced with Black Soldier Fly and Yellow Mealworm Fats

This trial investigated the effect of the dietary inclusion of Hermetia illucens (H) and Tenebrio molitor (T) fats as alternative lipid sources for growing rabbits, and assessed the carcass characteristics; proximate composition; lipid peroxidation, and fatty acid profile of the meat, as well as consumer acceptance. At weaning, 200 crossbred rabbits (1051 ± 138 g initial body weight) were allotted to five isolipidic (4% dry matter (DM)) dietary treatments: a control diet (C) containing 1.5% of soybean oil, and four experimental diets in which soybean oil was partially (50%) or totally (100%) substituted by H (H50 and H100) or T (T50 and T100) fats. The carcass characteristics, the meat quality traits, and the consumer acceptance of the cooked meat were not affected. The fat content of Longissimus thoracis et lumborum muscle of the rabbits was 1.1% on average. In the case of rabbit fed the H diets (average of diets H50 and H100), the same muscles revealed a higher saturated fatty acid proportion (47.1% vs. 39.7% and 40.8%, respectively) and a lower polyunsaturated fatty acid proportion than the rabbits fed the C and T diets (average of diets T50 and T100) (26.5% vs. 31.7% and 29.7%) (p < 0.001). The meat of the rabbits fed the diets containing insect fat (average for H and T diets) was less susceptible to oxidation (0.24 vs. 0.39 mg malondialdehyde/kg meat in the C group; p < 0.01).

Review: Insect meal: a future source of protein feed for pigs?

Are insects the farm animal of the future? A key agenda for agricultural production systems is the development of sustainable practices whereby food and feed can be produced in an environmentally efficient manner. These goals require novel approaches to complex problems and demand collaboration between scientists, producers, consumers, government and the general population. The provision of feed for animals is a major contributor to land and water use and greenhouse gas (GHG) emissions. Further, overfishing and a reduction in available land and water resources on which crops can be grown has led to an increase in price of protein ingredients such as fish meals and oils and soybean meals. Determination of novel solutions to meet the feed protein requirements of production animals is key to the development of sustainable farming practices. The Australian pork industry aims to develop production systems that efficiently use available resources (such as feed and energy) and limit the production of emissions (such as manure waste and GHGs). Invertebrates (insects e.g. black soldier flies) are naturally consumed by monogastric and aquatic species, yet the large-scale production of insects for feed (or food) is yet to be exploited. Most insects are low producers of GHGs and have low land and water requirements. The large-scale production of insects can contribute to a circular economy whereby food and feed waste (and potentially manure) are reduced or ideally eliminated via bioconversion. While the concept of farm-scale production of insects as domestic animal feed has been explored for decades, significant production and replacement of traditional protein sources has yet to be achieved. This review will focus on the potential role of insect-derived protein as a feed source for the Australian pig production industry.

The Effects of Diet Formulation on the Yield, Proximate Composition, and Fatty Acid Profile of the Black Soldier Fly (Hermetia illucens L.) Prepupae Intended for Animal Feed

Simple Summary

Mass rearing of the black soldier fly to be used as feed is still at an early stage. Among the different issues, larval feeding and nutrition of this species are the most relevant ones from a practical standpoint. For example, testing four different diets, we found that this insect can be efficiently reared on wheat byproducts in place of cornmeal and that using diets richer in carbohydrates or proteins can negatively affect protein accumulation, larval development, and survivorship. Accumulation of unsaturated fats in black soldier fly prepupae is a matter of great interest, and it was found to be directly dependent on the amount of these fats in the rearing substrates. By appropriately mixing different food byproducts as diet ingredients, our research suggests that black soldier fly prepupae meal suitable for the feed formulation can be obtained.

Abstract

The black soldier fly (BSF; Hermetia illucens L.) is a very promising insect species due to the ability to convert low-value substrates in highly nutrient feed. This work aimed to study the effect of three nominally isoenergetic diets containing plant ingredients such as barley, alfalfa, and wheat byproducts, formulated to be higher in nonfiber carbohydrates (TMD1), fibers (TMD2), and protein (TMD3) in comparison to an extensively genetic modified cereal (cornmeal)-based diet (C), on the growth, yield, and nutritive traits of BSF prepupae (BSFPs). Three growing trials with four biological replicates were carried out. Proximate and fatty acid analyses were performed on the diets and BSFPs. Feed conversion ratios (FCR), dry matter and nutrient yields, and apparent concentration factors (aBCF) for fatty acids (FAs) were calculated. Diet formulation had a substantial effect on the survival, development rate, and larval yield, but the FCR was unaffected. The BSFPs fed TMD3 did not result in a higher crude protein content in comparison to the C or TMD2 diets. Despite the leveled fat content of the diets, BSFPs reared on TMD1 were highest in fat, saturated FA, and fat yield. An apparent bioconcentration factor (aBCF) value lower than unity that was found for the unsaturated FA suggests that the BSFPs inefficiently absorb them from the diet or possibly turn them into saturated FA. However, the unsaturated FA accumulation in BSFPs depended on the levels that were found in the diet, which suggested some possibilities for the FA profile modulation. Overall, the TMD2 performed well despite the low-value of its main ingredients and high fiber content and can be considered to be a feasible option for the mass rearing of BSFPs that are intended for animal feed.

Animals Fed Insect-Based Diets: State-of-the-Art on Digestibility, Performance and Product Quality

In 2018, the industrial compound feed production throughout the world was 1103 metric billion tons, which was an increase of 3% compared to 2017. In order to meet the needs of the increasing population, a further increment in compound feed production is necessary. Conventional protein sources are no longer suitable to completely satisfy the increment of feed production in a sustainable way. Insects are one of the most promising options, due to their valuable nutritional features. This paper reviews the state-of-the-art of research on the use of insect meals and oils in aquatic, avian and other animal species diets, focusing mainly on the effects on digestibility, performance and product quality. In general, insect-derived product digestibility is affected by the insect species, the inclusion levels and by the process. Sometimes, the presence of chitin can lead to a decrease in nutrient digestibility. The same considerations are true for animal performance. As far as product quality is concerned, a dramatic effect of insect products has been recorded for the fatty acid profile, with a decrease in valuable n3 fatty acids. Sensory analyses have reported no or slight differences. Insect-derived products seem to be a good alternative to conventional feed sources and can make an important contribution to the sustainable development of the livestock industry.

The Potential Role of Insects as Feed: A Multi-Perspective Review

Simple Summary

The consumption of meat and fish is growing, and it is becoming increasingly difficult to meet the growing demand for protein by farming on land and in water, causing serious repercussions for the planet’s resources, socio-economic development, and environmental sustainability. The search for new food solutions with good nutritional value for direct and indirect human consumption is of fundamental importance. The use of insects for feeding farmed animals represents a promising alternative because of the nutritional properties of insects and the possible environmental benefits, given the sustainability of this type of farming. Yet, there is a lack of consensus among western consumers. Therefore, the aim of this paper is to report and discuss previous consumer and stakeholder studies related to insects as feed, including the main market challenges for this novel source. The results show that, despite a sparse body of research, consumer acceptance will not be a barrier towards the development of the insect protein industry for feed. However, further research should shed light on consumer willingness to pay for animal products from animals fed with insects and whether the overall acceptability, in general and from a sensory point of view, will be perceived better than conventional products.

Abstract

Recently, insects have received increased attention as an important source of sustainable raw materials for animal feed, especially in fish, poultry, and swine. In particular, the most promising species are represented by the black soldier fly (Hermetia illucens, HI), the yellow mealworm (Tenebrio molitor, TM), and the common house fly (Musca domestica, MD). Although rapid development is expected, insects remain underutilized in the animal feed industry mainly due to technical, financial, and regulatory barriers. In addition, few works have analyzed consumer and stakeholder points of view towards the use of insects as animal feed. In this article, we summarize the main findings of this body of research and provide a discussion of consumer studies regarding the consumption of animals fed with insects. Our review suggests that consumer acceptance will not be a barrier towards the development of this novel protein industry. Furthermore, we conclude that it will be of interest to understand whether the use of this more sustainable feed source might increase consumer willingness to pay for animal products fed with insects and whether the overall acceptability, from a sensory point of view, will be perceived better than conventional products. Finally, the main challenges of the feed farming industry are addressed.

Insects: a novel animal-feed protein source for the Australian market

The increasing demands on natural resources to provide food and feed has led to increased global initiatives to improve production sustainability and efficiency. The use of insects as an alternate source of protein for human food and production-animal feed is one such avenue gaining attention. With there being a large variety of insect species endemic to each region, there is likely to be an ideal candidate for each specific production system and region. Insects require less land and water than do terrestrial animals, have high feed-conversion efficiency (FCE) and emit low levels of greenhouse gases (GHG). Insect species currently investigated for mass production include black soldier fly larvae (BSFL), mealworms and crickets. In western societies, it is less likely that wide-scale adoption of insects as a food source will occur, although speciality products with ‘hidden’ insects, such as cricket flour, are commercially available. It is likely to be more achievable for insects to be included into the diets of production and companion animals. While there has been significant investment in research and development of large-scale insect-production systems, such facilities are yet to start producing at a significant scale. The safety and efficacy of insects as a food or feed must be established in conjunction with the development of mass rearing facilities and the optimisation of insect-rearing substrates. Insects also have nutraceutical properties that may have beneficial impacts on animal health and growth, with scope for these properties to be exploited as feed or food additives. The present review will explore the following question: ‘are insects a future livestock industry for Australia?’.