Insect and fish by-products as sustainable alternatives to conventional animal proteins in animal nutrition

The effect of yellow mealworm larvae meal supplementation in broiler diets on meat quality

The aim of this study was to evaluate the effect of Tenebrio molitor larvae meal supplementation in chicken diets on the chemical composition and sensory quality of meat. The experiment was conducted on 120 Ross 308 male broilers from day 12 to day 38 of their age. Broilers were divided into three equal groups with 5 replicates per treatment. The two experimental groups received feed mixtures containing 2% (TM2; n = 40) and 5% (TM5; n = 40), respectively of yellow mealworm (Tenebrio molitor L.) meal. The third group (TM0; n = 40) was control, receiving 0% of mealworms in diet. The addition of mealworm meal to diets in this trial do not worsen the chemical composition or sensory characteristics of the thigh meat of broilers. The control chickens had a higher live weight (P < 0.05) compared to the experimental groups at the end of the trial. The lowest live weight and feed intake was determined in group TM2 (P < 0.05). The highest feed intake (P < 0.05) was found in the control group. The breast meat from the control group was rated better (P < 0.05) in flavour compared to the groups receiving 2% and 5% of yellow mealworms. The primary requirement for the use of any ingredient in feed is that it does not adversely affect food safety and quality. In our study, the inclusion of 2% and 5% mealworm meal in the broiler’s diet had no influence on 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.

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.

A Multipurpose Leguminous Plant for the Mediterranean Countries: Leucaena leucocephala as an Alternative Protein Source: A Review

Simple Summary

The need to address the shortage of protein ingredients linked to both territoriality and growing demand pushes research to focus attention on alternative protein sources, both vegetable and animal (insects). This review describes the characteristics, uses, strengths, and weaknesses of Leucaena leucocephala, a legume that can be used in the zootechnical field as an alternative to traditional protein sources for feed formulation.

Abstract

In tropical and subtropical regions, as well as in the internal and/or marginal Mediterranean areas, one of the most important problems related to animal production is represented by the inadequate nutritional supplies. The low productivity of the animals, often connected to reduced annual growth, is, in fact, not infrequently attributable to the low nitrogen content and the high fiber content of the local plant species and crop residues that constitute the base ingredients of the rations commonly adopted by farmers. The use of the supplementation with arboreal and shrub fodder, although often containing anti-nutritional factors and toxins that limit its use, could be a profitable way to alleviate the nutritional deficiencies of the basic diets. Leucaena leucocephala (Lam.) De Wit is native to Central America and widely naturalized in the majority of Latin American countries. It is a legume suitable for tropical and subtropical environments including the countries of the Mediterranean area. Moreover, its spread is desirable if we consider the multiple uses to which it is suitable, the considerable amount of biomass produced, and its role in preserving the environment. The aim of this work was to highlight the characteristics of Leucaena that can justify its wide diffusion. A structured analysis of strengths and weaknesses was performed accordingly. Being a good protein source for feeding livestock, it could be a species to be introduced in the inland areas of the Mediterranean countries as an alternative protein source; the limit represented by the presence of anti-nutritional factors could be overcome by feed processing and by launching targeted research programs.

Appetite Regulation, Growth Performances and Fish Quality Are Modulated by Alternative Dietary Protein Ingredients in Gilthead Sea Bream (Sparus aurata) Culture

By answering the need for increasing sustainability in aquaculture, the present study aimed to compare growth, gene expression involved in appetite regulation, physical characteristics, and chemical composition of Sparus aurata fed alternative protein sources. Fish were fed ten iso-proteic, iso-lipidic, and isoenergetic diets: a vegetable-based (CV) and a marine ingredient-rich (CF) diet were set as control diets. The others were prepared by replacing graded levels (10, 20 or 40%) of the vegetable proteins in the CV with proteins from a commercial defatted Hermetia illucens pupae meal (H), poultry by-product meal (PBM) singly (H10, H20, H40, P20, P40) or in combination (H10P30), red swamp crayfish meal (RC10) and from a blend (2:1, w:w) of Tisochrysis lutea and Tetraselmis suecica (MA10) dried biomasses. The increase in ghre gene expression observed in MA10 fed fish matched with increased feed intake and increased feed conversion ratio. Besides, the MA10 diet conferred a lighter aspect to the fish skin (p < 0.05) than the others. Overall, no detrimental effects of H, PBM, and RC meal included in the diets were observed, and fish fatty acid profile resulted as comparable among these groups and CV, thus demonstrating the possibility to introduce H, PBM, and RC in partial replacement of vegetable proteins in the diet for Sparus aurata.

Safety of Mealworm Meal in Layer Diets and their Influence on Gut Morphology

Simple Summary

There is limited research on the use of the mealworm meal in laying hens’ diets and effects on relative organ weights, caecum microbiota, ileum morphology and digesta viscosity. All these parameters can affect the performance of animals, i.e., the laying and quality of eggs. The mealworm meal is a relatively new feedstuff, where it is necessary to exclude a possible harmful effect. Insect products have a beneficial nutrient content, but there are issues of stability, shelf life, storage and contamination, which could, in the case of negative properties, affect the morphology of the digestive tract, cause liver damage and, as a result, affect the animal performance parameters. The main objective of this study was to verify the safety of the mealworm meal in the feed of laying hens from 17–42 weeks of age. Therefore, the feed mixtures were tested in terms of microbiological stability, fungal and mycotoxin content and selected parameters of hens’ intestinal morphology and physiology were monitored. Feed mixtures with proportions of insect products were microbially stable even after four months. Based on the results of this study, use of two to five percent of mealworm meal in hen′s diet may be used as a sustainable and safe protein feed.

Abstract

The main objective of this study was to verify the safety of mealworm meal in the feed of laying hens from 17 to 42 weeks of age. Therefore, the feed mixtures were tested in terms of microbiological stability, fungal and mycotoxin content and selected parameters of hens’ intestinal morphology and physiology were monitored. The experiment was carried out with 30 Lohmann Brown Classic hens. Hens were divided by body mass into three equal groups with 10 replicates per treatment. The two experimental groups received feed mixtures containing 2% and 5% yellow mealworm (Tenebrio molitor L.) meal. The third group was a control group which had 0% of mealworm meal in the diet. Diets with 2% and 5% of mealworm meals did not affect the length of villi and microbiome of the caecum. The highest digesta viscosity from the ileum was found in the group with 5% mealworm, which may indicate a slower passage of the digesta through the digestive tract. Based on our results, it may be concluded that the proportion of mealworm meals does not deteriorate the quality of feeds. Mealworm meal does not negatively affect microbial stability in experimental feeds. Therefore, it can be recommended the two and (or) five percent of mealworm meal inclusion in hen’s diet.

Dietary inclusion of a partially defatted black soldier fly (Hermetia illucens) larva meal in low fishmeal-based diets for rainbow trout (Oncorhynchus mykiss)

Background

Recent investigations highlighted that Hermetia illucens (BSF) larva meal can be a valuable alternative protein source for aquafeed production. In this study, in substitution of fishmeal, we used increasing inclusion levels of a partially defatted BSF larva meal in low fishmeal-based diets for rainbow trout (Oncorhynchus mykiss Walbaum) and we evaluated the related implications in terms of growth performance, physical characteristics, proximate and fatty acid (FA) compositions of the fillets, gut and liver histology, and diet digestibility. In a 131-day trial, 576 fish (100.1 ± 9.29 g) were randomly allotted to 24 tanks (24 fish/tank, 4 replicates/treatment). Six experimental diets were produced to have partial replacement of fishmeal (0, 10%, 20%, 30%, 40% and 50%) by increasing levels of BSF meal (0% [BSF0], 3% [BSF3], 6% [BSF6], 9% [BSF9], 12% [BSF12] and 15% [BSF15] on as fed basis, respectively).

Results

No differences were observed among the treatments for all the considered growth performance parameters. The viscero and hepato-somatic indexes showed significant differences among the treatments, with the highest values observed in the BSF15 group. No differences were recorded in terms of fillet’s physical characteristics, dry matter (DM), crude protein (CP) and ether extract (EE) contents. Total saturated and monounsaturated FA increased, while polyunsaturated FA (particularly n-3 FA) decreased while increasing the HI meal inclusion in the diet. Histopathology of liver and gut was not affected, whereas, in posterior gut, villi were higher in BSF6 and BSF9 compared to BSF3 fish. The apparent digestibility of DM, CP, EE and gross energy did not vary among the treatments.

Conclusions

These results suggest that a partially defatted BSF meal could be included up to 15% in low fishmeal-based diets for rainbow trout with no adverse effects on growth performance, fillet’s physical characteristics, gut and liver health, and diet digestibility. On the contrary, the fillet FA composition worsened while increasing the level of BSF meal in the diet.

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

Objective

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

Materials and Methods

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

Results

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

Conclusion

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

Intestinal microbial communities of rainbow trout (Oncorhynchus mykiss) may be improved by feeding a Hermetia illucens meal/low-fishmeal diet

With demands and reliance on aquaculture still growing, there are various challenges to allow sustainable growth and the shift from fishmeal (FM) to other protein sources in aquafeed formulations is one of the most important. In this regard, interest in the use of insect meal (IM) in aquafeeds has grown rapidly. Accordingly, the aim of the present study was to assess the effects of dietary IM from Hermetia illucens (Hi) larvae included in a low-FM diet on gut microbial communities of rainbow trout (Oncorhynchus mykiss), in terms of both composition and function of microbiome. A feeding trial was conducted using 192 trout of about 100-g mean initial weight. Fish were fed in quadruplicate (4 tanks/diet) for 131 days with two diets: the control (Ctrl) contained 20% of FM as well as other protein sources, whereas the Hi diet contained 15% of Hi larvae meal to replace 50% of the FM contained in the Ctrl diet. High-throughput sequencing of 16S rRNA gene was used to identify the major feed and gut bacterial taxa, whereas Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis was performed on gut bacterial genomes to identify the major active biological pathways. The inclusion of IM led to an increase in Firmicutes, mainly represented by Bacilli class and to a drastic reduction of Proteobacteria. Beneficial genera, such as Lactobacillus and Bacillus, were enriched in the gut of fish fed with the Hi diet, whereas the number of bacteria assigned to the pathogenic Aeromonas genus was drastically reduced in the same fish group. The metagenome functional data provided evidence that dietary IM inclusion can shape the metabolic activity of trout gut microbiota. In particular, intestinal microbiome of fish fed with IM may have the capacity to improve dietary carbohydrate utilization. Therefore, H. illucens meal is a promising protein source for trout nutrition, able to modulate gut microbial community by increasing the abundance of some bacteria taxa that are likely to play a key role in fish health.

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.

Protein-Based Films and Coatings for Food Industry Applications

Food packaging is an area of interest not just for food producers or food marketing, but also for consumers who are more and more aware about the fact that food packaging has a great impact on food product quality and on the environment. The most used materials for the packaging of food are plastic, glass, metal, and paper. Still, over time edible films have become widely used for a variety of different products and different food categories such as meat products, vegetables, or dairy products. For example, proteins are excellent materials used for obtaining edible or non-edible coatings and films. The scope of this review is to overview the literature on protein utilization in food packages and edible packages, their functionalization, antioxidant, antimicrobial and antifungal activities, and economic perspectives. Different vegetable (corn, soy, mung bean, pea, grass pea, wild and Pasankalla quinoa, bitter vetch) and animal (whey, casein, keratin, collagen, gelatin, surimi, egg white) protein sources are discussed. Mechanical properties, thickness, moisture content, water vapor permeability, sensorial properties, and suitability for the environment also have a significant impact on protein-based packages utilization.

Soybean Molasses in Animal Nutrition

Simple Summary

Soybean molasses is a by-product of the soybean processing industry that is accumulated in large quantities and usually disposed of like liquid manure or in landfills, thus causing severe ecological problems. At the same time, soybean molasses has a promising potential to be included regularly in animal diets because of its high nutritive value and functional properties. It is rich in sugars and is a cheap energy source for animals compared to other energy-rich feed ingredients. This paper reviews current knowledge on the valorization of soybean molasses as an alternative feed ingredient focusing on its composition and application in animal nutrition in general.

Abstract

Concerning the increasing global demand for food and accumulation of huge amounts of biomass waste from the agro-food industry whose manipulation is usually inadequate, the potential of livestock to convert by-products as alternative feed ingredients into valuable proteins has been proposed as an outstanding option. Soybean molasses present a by-product of soybean protein concentrate production with low commercial cost but high nutritive and functional value. It is a rich source of soluble carbohydrates in the form of sugars and soybean phytochemicals. Therefore, this paper provides a review of published works about the production of soybean molasses, chemical composition, and nutritive value. In addition, the possibility of the application of soybean molasses in animal nutrition as a pelleting aid and functional feed ingredient is also discussed. Special attention is devoted to the influence of the inclusion of soybean molasses in the diets for ruminants, non-ruminants, and aquaculture on animal performance and health.

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.

Replacement of Fish Meal by Black Soldier Fly (Hermetia illucens) Larvae Meal: Effects on Growth, Haematology, and Skin Mucus Immunity of Nile Tilapia, Oreochromis niloticus

Simple Summary

Fish meal (FM) is the primary ingredient of the farmed fish’s diet. However, the decline in wild fish catches, and the growing demand for aquaculture feed have resulted in a dramatic reduction of FM supply. Thus, it is essential to seek for alternatives, such as insect meal (IM), to support sustainable aquafeed production. Among insects, the black soldier fly larvae are promising because they are rich in essential amino acids, minerals, and vitamins. Therefore, the present study was performed to assess the effects of IM as a partial or total replacement of FM on the growth and hematological parameters and skin mucus immunity of Nile tilapia. Growth and feed utilization efficiency indices, feed intake, survival rates, and hematological parameters were not significantly different between FM and IM fed fish, while the mucosal immune response was improved in IM fed fish. In conclusion, these results show that IM can be used to substitute FM in the Nile tilapia diet. These findings can be used to develop alternative aquafeed for sustainable aquaculture.

Abstract

Fish meal (FM) is no longer a sustainable source for the increasing aquaculture industry. Animal proteins from insects may be used as a FM alternative source as long as they do not create adverse effects in fish. Black soldier fly larvae meal (BSFLM) was tested in a 12-week experiment on Nile tilapia (Oreochromis niloticus). Four hundred and twenty (14.77 ± 2.09 g) fish were divided into seven groups and were fed seven diets: control (0% BSFLM-100% FM), and FM replaced by BSFLM at rates of 10%, 20%, 40%, 60%, 80% and 100%. Growth indexes, feed utilization efficiency indices, feed intake, and survival rate were not significantly different (p > 0.05) between FM and BSFLM fed fish. Values of red blood cell, white blood cells, hemoglobin, hematocrit, mean corpuscular volume and hemoglobin, mean corpuscular hemoglobin concentration, red blood cell distribution width, and platelet values were not affected by BSFLM. Skin, mucus lysozyme, and peroxidase activities were improved in BSFLM fed fish. BSFLM can be used as a substitution for FM in the Nile tilapia (O. niloticus) diet at up to a 100% rate with no adverse effects.

Supplementation of Hermetia illucens Larvae in Poultry By-Product Meal-Based Barramundi, Lates calcarifer Diets Improves Adipocyte Cell Size, Skin Barrier Functions, and Immune Responses

A 6-week feeding trial was performed to examine the effects of supplementing Hermetia illucens (HI) larvae meal when fishmeal (FM) was replaced with poultry by-product meal (PBM) in juvenile barramundi, Lates calcarifer diet. The effect was evaluated in terms of barramundi growth, filet quality, internal tissue structure, serum biochemistry, skin neutral mucins, immune response, and resistance to Vibrio harveyi. Three isonitrogenous (48% crude protein) and isolipidic (18% crude lipid) diets: an FM-based diet (control) and two diets containing 60 and 75% of PBM supplemented with 10% HI larvae (60PBM + HI and 75PBM + HI) were formulated. A total of 225 barramundi, with an average weight of 15.87 ± 0.14 g, were randomly distributed into nine tanks, each holding 25 fish. There were no significant effects of test diets on growth, but feeding HI-supplemented PBM diets significantly increased the survival rate. A significantly reduced intraperitoneal fat index in HI-supplemented-PBM-fed fish was correlated to a decreased size of peritoneal adipocytes. The observation of no histopathological alteration of the liver in the HI-supplemented-PBM-fed fish was further supported by significant alterations in serum biochemistry, in particular, a decreasing tendency of alanine transaminase, glutamate dehydrogenase, and total bilirubin. A 14-day challenge with V. harveyi indicated that HI-supplemented PBM diets reduced the infection rate in barramundi. After 24 h of infection, increased serum (lysozyme) and skin barrier functions, down-regulation of interleukin-1beta, and upregulation of interleukin-10 were found in HI-supplemented-PBM-fed fish.

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.

Lactobacillus plantarum in black soldier fly (Hermetica illucens) meal modulates gut health and immunity of freshwater crayfish (Cherax cainii)

Probiotic supplements are being used to improve the growth and immune performance of aquaculture species over the last couple of decades. In recent times, black soldier fly (BSF) is considered as one of the promising sources of alternative protein to fishmeal protein in aqua-diets. Since the freshwater crayfish, marron (Cherax cainii), a Western Australian's native and iconic freshwater crayfish species, grows fairly slow under commercial farming environment, this study was aimed to investigate the supplemental effect of BSF and BSF with probiotic bacteria Lactobacillus plantarum (BSFLP) on overall health and immune performance of marron after 56 days of feeding under laboratory conditions. The post-trial data revealed insignificant influences of any diets on growth performance, however, both BSF and BSFLP based diets significantly improved some haemolymph parameters and gut health of marron. High throughput sequence data revealed that both BSF and BSFLP diets significantly improved the diversity of microbial communities including some beneficial bacteria for crustaceans in the hindgut of marron. Further analysis showed that both BSF and BSFLP diets upregulated the expression of some genes in the gut tissue and haemocytes associated with the innate immune response of marron at 48 h post injection. The up-regulation of some immune genes in BSFLP diet group was found significantly linked to OTU abundance for Lactobacillus. The findings of this study could be helpful for improving overall health status of marron.

Evaluation of the Low Inclusion of Full-Fatted Hermetia illucens Larvae Meal for Layer Chickens: Growth Performance, Nutrient Digestibility, and Gut Health

Substitution of feed protein source with defatted black soldier fly larvae meal (BSFM) has been evaluated intensively in poultry, but information about full-fatted BSFM is still very limited. The aim of the present study was to investigate the effect of dietary low inclusion of full-fatted BSFM on the growth performance, plasma antioxidant ability, nutrient digestibility, and gut health of layer chickens during 1-42 days of age. A total of 480 female 1-day-old Hy-Line Brown chickens were divided into four dietary treatments, with the inclusion of 0, 3, 6, and 9% of full-fatted BSFM. Each treatment included six replicates and 20 birds per replicate. As dietary full-fatted BSFM inclusion levels increased, there was a quadratic increase in final weight and average daily gain and a quadratic decrease in feed/gain ratio. Dietary full-fatted BSFM inclusion levels increased the digestibility of crude protein and ether extract quadratically as well as ileum mucosal sIgA concentration linearly, but these had no effect on intestinal morphology. Additionally, an increase in dietary full-fatted BSFM inclusion levels resulted in a linear increase in glutathione peroxidase and total superoxide dismutase activities and a linear decrease in malondialdehyde content in plasma. The encouraging results of the improvement of growth performance, nutrient digestibility, antioxidant ability, and gut health parameters suggested that partially full-fatted BSFM inclusion can be suitable protein ingredients for layer chickens' diets at the starter period.

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.

Evaluation of Long Sea Snail Hinia reticulata (Gastropod) from the Middle Adriatic Sea as a Possible Alternative for Human Consumption

In mid Adriatic Sea the common sea snail is the habitual snail eaten, but over the years fishermen started to capture also the long sea snail, a possible alternative for human consumption. This study aims to compare the quality traits of the edible fraction in the common and long sea snails. In this study, common and long sea snail samples were provided by fishermen in November 2018 and March 2019. Total weight (meat and shell), fractions of meat and shell (after having extracted the edible part), fatty acid, elements in meat, and calcium content in shells were determined. Meat quality traits showed high nutritional value without significant differences between the two species. The fatty acid profile showed n3/n6 ratio significantly different both considering the season of sampling (November: 4.1; March: 2.38) and the species of sea snail (common: 4.98; long: 2.86). The long species showed a higher yield in the total body and calcium content concentrations. However, the long sea snail showed 50% lower meat yield compared with the common sea snail. In conclusion, the long sea snail can be used as an alternative to the common sea snail for human consumption.

Effects of Partially Defatted Hermetia illucens Meal in Rainbow Trout Diet on Hepatic Methionine Metabolism

Simple Summary

For sustainable aquaculture development, fish meal from the sea in aquafeed should be replaced with other sustainable materials such as insect larvae. The authors fed black soldier fly maggot meal to rainbow trout and examined the expression of three genes and two metabolites involved in turn-over of methionine that is an essential amino acid in fish. According to the increase in the maggot content in the aquafeed, gene expression was modulated to maintain an optimal level of methionine metabolites. Dietary replacement of up to 50% of fish meal with the maggot meal was acceptable, implying future development of a new aquafeed for sustainable aquaculture.

Abstract

This study investigated, for the first time, the effects of replacement of fishmeal (FM) with insect meal from Hermetia illucens (HI) on the transcript levels of three genes involved in methionine (Met) metabolism in rainbow trout (Oncorhynchus mykiss) liver. Two target genes—betaine-homocysteine S-methyltransferase (BHMT) and S-adenosylhomocysteine hydrolase (SAHH)—are involved in Met resynthesis and the third one—cystathionine β synthase (CBS)—is involved in net Met loss (taurine synthesis). We also investigated the levels of two Met metabolites involved in the maintenance of methyl groups and homocysteine homeostasis in the hepatic tissue: S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). Three diets were formulated, an FM-based diet (HI0) and two diets in which 25% (HI25) and 50% (HI50) of FM was replaced with HI larvae meal. A 78-day feeding trial involved 360 rainbow trout with 178.9 ± 9.81 g initial average weight. Dietary replacement of up to 50% of FM with HI larvae meal, without any Met supplementation, did not negatively affect rainbow trout growth parameters and hepatic Met metabolism. In particular, Met availability from the insect-based diets directly modulated the transcript levels of two out of three target genes (CBS, SAHH) to maintain an optimal level of one-carbon metabolic substrates, i.e., the SAM:SAH ratio in the hepatic tissue.

The Effect of Hydrolyzed Insect Meals in Sea Trout Fingerling (Salmo trutta m. trutta) Diets on Growth Performance, Microbiota and Biochemical Blood Parameters

Simple Summary

The replacement of fishmeal by environmentally sustainable alternative meals has been one of the targets in aquaculture in recent decades. A number of factors support the use of insect meals, as a group of products characterized by high crude protein and crude fat content, in fish nutrition. Insects are readily accepted by a number of fish species, and they are part of the natural diet of omnivorous and carnivorous species. The present study was conducted to evaluate the effects of hydrolyzed Tenebrio molitor and Zophobas morio meals as a partial replacement for fishmeal in sea trout (Salmo trutta m. trutta) diets on growth performance, feed utilization, organosomatic indices, serum biochemistry, gut histology, and microbiota. In the present study, insect meals inclusion did not cause any adverse impacts on growth performance, feed utilization or gut histomorphology. However, an effect on the organosomatic indices, serum biochemistry, and microbiota was observed. In conclusion, hydrolyzed T. molitor and Z. morio meals seem to be promising alternative protein sources for sea trout nutrition.

Abstract

The present study is the first introduction of hydrolyzed superworm meal in sea trout nutrition. It was conducted to evaluate the effects of inclusion in the diet of hydrolyzed insect meals as a partial replacement for fishmeal on growth performance, feed utilization, organosomatic indices, serum biochemical parameters, gut histomorphology, and microbiota composition of sea trout (Salmo trutta m. trutta). The experiment was performed on 225 sea trout fingerlings distributed into three groups (3 tanks/treatment, 25 fish/tank). The control diet was fishmeal-based. In the experimental groups, 10% of hydrolyzed mealworm (TMD) and superworm (ZMD) meals were included. The protein efficiency ratio was lower in the TMD and ZMD. Higher organosomatic indices and liver lipid contents were found in the group fed ZMD. The ZMD increased levels of aspartate aminotransferase, and decreased levels of alkaline phosphatase. The Aeromonas spp. and Enterococcus spp. populations decreased in the ZMD. The concentrations of the Carnobacterium spp. decreased in the ZMD and TMD, as did that of the Lactobacillus group in the TMD. In conclusion, insect meals may be an alternative protein source in sea trout nutrition, as they yield satisfying growth performance and have the capability to modulate biochemical blood parameters and microbiota composition.