Effect of dietary lupine seeds (Lupinus luteus L.) and different insect larvae meals as protein sources in broiler chicken diet on growth performance, carcass, and meat quality

Yellow mealworm as an alternative to conventional plant- and animal-based protein sources in feedlot lambs' diets: Implications on blood parameters, growth and slaughter performance, carcass traits, and meat quality

This study evaluates the effects of Tenebrio molitor meal (TMM) as an alternative to conventional plant-based (soybean meal, SBM) and animal-based (fishmeal, FM) protein sources on blood parameters, growth and slaughter performance, carcass traits, and meat quality of feedlot lambs. A total of 24 Suffolk lambs [3 months of age, 21.4 ± 1.08 kg body weight (BW)] were allocated for 60 days to three treatments (8 lambs per treatment) in a completely randomized design, as follows: 1- SBM at 150 g/kg dry matter (DM)], 2- FM at 50 g/kg DM, and 3- TMM at 60 g/kg DM. Feed intake, BW, and blood samples were collected on days 0, 20, 40, and 60. At the end of the trial, the lambs were slaughtered for carcass evaluation and meat quality assessment. The average daily gain was higher for SBM-fed than for TMM-fed lambs (0.25 and 0.21 kg/d; P < 0.001). Plasma levels of creatinine were higher in FM-fed when compared to SBM-fed lambs, while TMM-fed lambs showed intermediate values (88.72, 85.69 and 87.57 μmol/L, respectively; P < 0.05). The hot and cold carcass weights (15.99 and 15.52 kg vs 18.49 and 18.03 kg) and yields (44.31 and 43.02 % vs 46.03 and 44.87 %) were lower in the TMM group compared with the SBM group (P < 0.05). The dietary treatment had no effect (P > 0.05) on meat pH, color, texture, water loss and contents of fat, protein, and moisture. Further research should evaluate optimal inclusion levels of TMM in combination with conventional protein sources to avoid negative economic implications.

Review: Insects as a novel feed ingredient: processing technologies, quality and safety considerations

The current food system is placing significant strain on limited available resources. Novel protein sources have been suggested as a potential solution for ensuring further growth without compromising the natural balance of the planet. In this direction, edible insects appear to be crucial players. Consumers may not always prefer the direct use of insects as human food, indicating that the indirect use of insects as animal feed might be more suitable. Insects are characterised by high nutritional value and similar digestibility compared to more traditional feed such as soybean meal and fishmeal. However, effective introduction of edible insects in animal diets requires one or more processing operations. Processing is paramount for ensuring high microbiological safety while improving the quality, digestibility and palatability of the insect. Additionally, feed processing could allow a combination of insect-based ingredients with other traditional feed ingredients, obtaining a uniform and stable mixture, which can easily and conveniently be provided to the farmed animals. In this review, an overview of the most common processing methods (blanching, grinding, drying, mixing, extrusion) applied to edible insects with the aim of delivering high-quality insect-based feed is presented. Each processing step is carefully evaluated, the pros and cons of each operation are considered and important recommendations are provided. Barriers and opportunities for advancing the use of insects within the feed sector are finally illustrated. A strong emphasis is placed on the need of evaluating the effect of any processing step on the quality and safety of insect-derived products, particularly considering the possibility of replacing traditional feed ingredients with insect-derived materials.

Substitution of soybean meal for yellow mealworm meal in the diet of slow-growing chickens provides comparable carcass traits and meat quality

1. This study investigated the effects of incorporating yellow mealworm (Tenebrio molitor) larval meal as a partial and/or complete substitute for soybean meal on carcass and meat quality in slow-growing chickens.2. A total of 256 one-day-old male broilers were randomly allocated to 1 of 32 experimental units distributed among four treatments (n = 8): the control treatment (C), where soybean (SB) meal was the protein source, and three experimental treatments, in which SB meal was replaced by Tenebrio molitor (TM) larval meal at levels of 50% (T1), 75% (T2) and 100% (T3), respectively. Three different feed phases (1-29; 29-57 and 57-92 d of age) were used for each treatment. All chickens were slaughtered at 92 d of age, with eight animals per treatment randomly selected to assess carcass and meat quality. Near-infrared reflectance spectroscopy (NIR) was used to classify meat quality.3. Carcass traits were not significantly different between treatments, except for head and thigh weight, which were higher in the control group (p < 0.01). In terms of physicochemical characteristics, treatment T2 showed less yellowness (p < 0.05), while water and cooking losses were lower in treatments T1 and T2 (p < 0.01). Meat from both T1 and T2 groups had lower shear forces (p < 0.01), higher moisture content (p < 0.01) and less protein (p < 0.05) compared to treatments C andT3. Birds fed T3 had the highest meat ash content (p < 0.01). Chickens consuming TM had higher monounsaturated fatty acid (MUFA) levels and lower polyunsaturated fatty acid (PUFA) and n-6 acidsPUFA (p < 0.01).4. Substitution of SB with TM is a protein alternative for slow-growing chickens that supports carcass and meat quality comparable to those fed a conventional diet.

Inclusion of Tenebrio molitor larvae meal in the diet of barbary partridge (Alectoris barbara) improves caecal bacterial diversity and composition

In this study, we investigated the influence of the inclusion of Tenebrio molitor (TM) larvae meal in the diet on the diversity and structure of the bacterial community in the caecal content of Barbary partridges. A total of 36 partridges, selected randomly for slaughter from 54 animals, were divided equally into three treatment groups, including the control group (C) with a diet containing corn-soybean meal and two experimental groups, in which 25% (TM25) and 50% (TM50) of the soybean meal protein was replaced by the meal from TM larvae. After slaughtering, the bacterial community of the 30 caecal samples (10 samples per each experimental group) was analysed by high-throughput sequencing using the V4-V5 region of the 16 S rRNA gene. Alpha diversity showed a higher diversity richness in the TM50 group. Beta diversity showed statistical dissimilarities among the three groups. Firmicutes was the dominant phylum regardless of the diet, with the predominant families Ruminococcaceae and Lachnospiraceae. Clostridia and Faecalibacterium were decreased in both TM groups, Lachnospiraceae was suppressed in the TM50 group, but still this class, genus and family were abundantly present in all samples. Several potentially beneficial genera, such as Bacillus, Ruminococcaceae UCG-009, Oscillibacter and UC1-2E3 (Lachnospiraceae) were increased in the TM50 group. The results showed a beneficial effect of the T. molitor larvae meal on the caecal microbiota of Barbary partridges, particularly in the TM50 group, which showed an increase in bacterial diversity.

Optimizing food waste bioconversion with sodium selenite-enhanced Lucilia sericata maggots: a sustainable approach for chicken feed production and heavy metal mitigation

Recycling food waste by feeding it to insects can result in the continuous production of high-quality animal feed protein and organic fertilizer. However, the bioconversion efficiency and safety of using insects as feed protein for animal breeding are important factors limiting the development of this technology. Therefore, we aimed to optimize the efficiency of bioconversion of food waste using Lucilia sericata maggot (LSM). Sodium selenite (SS) was used to improve the quality and safety of each trophic-level organism. The results showed that an SS concentration of 15 mg kg-1 w.w. in the food waste culture substrate (SS15), the yield and quality of the obtained LSMs were optimal. The total selenium (Se) content of LSMs was 82.4 ± 1.16 mg kg-1 d.w., and non-inorganic Se accounted for 96.4% ± 2.01% of the total Se content. Additionally, the conversion efficiency of food waste was 18.7% higher than that in the control group (p < 0.05). When SS15 was used to raise maggots as a protein substitute for fish meal (commercial feed), the weight of the chickens and the crude protein content were 1.09-1.26 times and 1.09-1.13 times, respectively (p < 0.05), in comparison with the corresponding findings obtained with the use of ordinary maggots and commercial feed. In this group, glutathione peroxidase, superoxide dismutase, catalase, and immunoglobulin A and G activities were significantly higher than those obtained with the other feeds (p < 0.05). During this cyclic utilization process, the total Se content in chickens (0.31 ± 0.05 mg kg-1 w.w. in the breast, 0.19 ± 0.01 mg kg-1 w.w. in the leg, and 0.57 ± 0.01 mg kg-1 w.w. in the liver) significantly increased (p < 0.05). Meanwhile, the Cu and Zn contents in the LSMs and chickens increased, whereas cadmium, lead, chromium, and nickel absorption was inhibited (p < 0.05). Health risk assessment based on the levels of Se and heavy metals showed that Se-enriched chickens produced using this method can be safely consumed.

A methodological review in sensory analyses of chicken meat

The sensory characteristics of poultry products are crucial in defining their quality and widely influence consumer choices. Even though the scientific literature clearly indicates that for muscle foods the sensory profile is relevant in purchase decisions and overall acceptability, sensory evaluation has often been underestimated and considered complementary to instrumental and/or chemical assessments. Sensory analysis includes different types of validated tests (discriminative, descriptive, and affective), applied depending on the purpose of the research study, requiring special attention in the sample preparation phase, in particular for nonhomogeneous products such as poultry meat, requiring reproducible cutting, cooking and presentation to the tasters. The aim of this paper is to review, critically assess and discuss sensory methods, standardized procedures and sample preparation tailored for chicken meat, through the literature from 2000 to 2023, with a section dedicated to ethical aspects that must be carefully considered when designing a sensory protocol. The target readers are both the research and the business communities, as the information can be widely applied for quality control, to develop new food products, to understand or drive preferences or, for example, to assess potential sensory differences among chickens fed with different diets. To the best of the authors' knowledge, this review represents a useful first guide for those approaching the sensory analysis of chicken meat.

A meta-analysis of the meat physicochemical parameters of broiler chickens fed insect-based diet

A total of 23 studies were identified in a literature search performed in the Scopus, Science Direct and Google Scholar databases for meta-analysis. The criteria used include studies that were published from 2015 to 2023 and those reporting the effects of insect meal utilisation in poultry diets. Data on live weight (LW), carcass weight (CW), moisture, meat pH, lightness (L*), redness (a*), yellowness (b*), proximate composition (protein, fat and ash content) and shear force in broilers were subjected to OpenMEE software, and data were pooled using a random-effect model. Subgroup analysis and meta-regression were performed to ascertain the influence of dietary insect meals on the response of meat aspects and the source of heterogeneity, respectively, using the following moderators (insect species, dosage level, feeding duration and age at slaughter). The results indicated that dietary insect meal did not affect LW, CW, meat L*, pH, shear force, moisture, fat and ash content. In contrast, dietary insect meal increased the a* of the meat (standardised mean differences (SMDs) = 1.03; 95% confidence intervals (CIs) = 0.484-1.578; p ≤ 0.001), b* (SMD = 1.117; 95% CI = 0.334-1.90; p = 0.005), and meat protein content (SMD = 0.365; 95% CI = 0.031-0.7; p = 0.032). The subgroup analysis showed that insect meal dosage of ≤10% and age at slaughtered ≤35 days had improved the LW, CW and meat L*. In addition, the meat a*, protein and ash content were also influenced by insect species, dosage levels and age at slaughter. In conclusion, ≤10% of either Hermetia illucens or Tenebrio molitor can be included in broiler diets without compromising the LW, CW, meat pH, colour, shear force, moisture, fat and ash content in broilers. The study therefore indicated that insect meals have a bright future as an alternative protein source in poultry diets.

Potential uses of silkworm pupae (Bombyx mori L.) in food, feed, and other industries: a systematic review

The increasing pressures imposed on ecosystems by the growing needs of the human population are stimulus for research into innovative and unconventional sources of raw materials for different industries. This systematic review was carried out to investigate the available literature on the possible industrial uses of silkworm (Bombyx mori L.) pupae, a residue of silk production. The review was conducted using an adapted version of PRISMA. After a screening process, 105 articles were obtained and subjected to a detailed quantitative and qualitative analysis. It was found that in the last decade there has been a significant increase in the number of papers devoted to the study of the potential use of silkworm pupae in different applications, with a significantly higher number in the last three years of the scope of this review, indicating a growing interest in the subject. From the analysis of the information collected, promising uses in human and animal food, such as fish, mammalian, poultry, swine and companion animals, as well as potential uses for the pharmaceutical industry, were identified. The evaluated research identified compounds with antioxidant activity and important contents of unsaturated fatty acids, which are related to beneficial effects on cardiovascular health, diabetes control, reduction of the risk of developing certain types of cancer and inflammatory activity, among other benefits. One of the most relevant findings is that many studies report a significant concentration of α-linolenic acid in silkworm pupae oil, which is attributed with anticancer, anti-inflammatory, antioxidant, anti-obesity and neuroprotective properties, among others.

Dietary inclusion of defatted silkworm (Bombyx mori L.) pupa meal in broiler chickens: phase feeding effects on nutritional and sensory meat quality

The present experiment was conducted to test the effect of a 4% defatted silkworm (Bombyx mori) pupae meal (SWM) incorporation into chickens' diets at different growth phases on meat quality characteristics and sensory traits. Ninety ROSS 308 day-old male broiler chickens were randomly assigned to 3 dietary groups, with 5 replicated pens/diet: the first group received a control (C) diet throughout the growing period of 42 d, the second group received a diet with 4% SWM (SWM1) during the starter phase (1-10 d) and the C diet up to slaughter, whereas the third group was fed the C diet during the starter phase and 4% SWM during the grower and finisher phases (SWM2). Diets were isonitrogenous and isoenergy, and birds had free access to feed and water throughout the experimental trial. At 42 d of age, 15 chickens/treatment were slaughtered at a commercial abattoir. Fatty acid (FA) and amino acid (AA) profiles and contents of meat, as well as its oxidative status, were determined in both breast and leg meat cuts. Also, a descriptive sensory analysis was performed on breast meat by trained panelists. Results highlighted that the SWM2 treatment increased the n-3 proportion and content in both breast and leg meat, thereby improving the omega-6/omega-3 (n-6/n-3) ratio in both cuts (P < 0.001). However, the dietary treatment had no significant effect on the oxidative status of either breast or leg meat (P > 0.05). The SWM had a limited impact on overall sensory traits of breast meat, but it contributed to improve meat tenderness in SWM-fed chickens (P < 0.01). Furthermore, SWM1 meat exhibited higher juiciness (P < 0.05) and off flavor intensity (P < 0.05) compared to the control meat. Overall, the present experiment indicated that defatted SWM holds promise as an alternative ingredient in chicken rations, ensuring satisfactory meat quality. Furthermore, administering SWM during the grower-finisher phase demonstrated beneficial effects on meat healthiness, ultimately enhancing n-3 fatty acids content and reducing the n-6/n-3 ratio.

A Systematic Review and Metanalysis on the Use of Hermetia illucens and Tenebrio molitor in Diets for Poultry

Insect meal as a protein source has been considered a sustainable way to feed animals. H. illucens and T. molitor larvae meal are considered high-protein sources for poultry, also presenting considerable amounts of fatty acids, vitamins, and minerals. However, other potential components in insect meal and insect oil have been more extensively studied in recent years. Chitin, lauric acid, and antimicrobial peptides can present antimicrobial and prebiotic functions, indicating that low levels of their inclusion in insect meal can beneficially affect broilers' health and immune responses. This systematic review was developed to study the impact of insect products on the health parameters of broilers, and a metanalysis was conducted to evaluate the effects on performance. A database was obtained based on a selection of manuscripts from January 2016 to January 2023, following the mentioned parameters. Both H. illucens and T. molitor meal or oil products had positive effects on poultry health status, especially on the ileal and cecal microbiota population, immune responses, and antimicrobial properties. The average daily gain was greater in broilers fed T. molitor meal compared to H. illucens meal (p = 0.002). The results suggest that low levels of insect meal are suitable for broilers, without resulting in negative effects on body weight gain and the feed conversion ratio, while the insect oil can totally replace soybean oil without negative impacts.

Consumer Expectation and Perception of Farmed Rainbow Trout (Oncorhynchus mykiss) Fed with Insect Meal (Tenebrio molitor)

In recent years, insect meal has attracted increasing interest as an innovative protein source to replace fish meal in feed formulations due to its valuable nutritional profile. This research aimed to compare the effects of different levels of dietary inclusion of the yellow mealworm beetle (T. molitor) larvae meal on the sensory quality of rainbow trout (Oncorhynchus mykiss) fillets and retrospectively on the acceptability of this protein source to consumers. The results showed that the inclusion of T. molitor larvae meal did not induce sensory changes in the trout fillets, while regarding consumer acceptability and willingness to buy and pay, it was shown that a certain level of rejection towards this alternative protein still exists. The work described in this scientific manuscript adds more knowledge on the study of consumer acceptability of this protein source.

Review: Recent advances in insect-based feeds: from animal farming to the acceptance of consumers and stakeholders

The search for new, alternative and sustainable feeding sources, including insects, has become an important challenge on the feed market. In 2017, the European Union (EU) started to allow the use of insect meals as feeds for fish. In addition, in 2021, the EU also authorised the use of insect meal for pig and poultry farming. However, the adoption of insect meal by the European aquaculture sector is still limited, and this is mostly due to the lack of availability of insects and their higher costs than conventional feed ingredients. Thus, the insect-based feed industry is still in its infancy, and its successful development and integration in the food value chain depend on several factors. Among these, the technical feasibility and production of quality products, and acceptance by European consumers and farmers are relevant factors. To address these points, this narrative review describes the state of the art of the potential role of insect-based feeds. The stakeholders' and consumers' perspectives are investigated, along with the effects of insect-based feeds on the production and nutritional values of fish, poultry (meat and eggs), and pork. Indeed, matching the nutritional values of insect products with conventional feeds is one of the future challenges of the insect sector, as their nutritional composition is highly dependent on the rearing substrates, and thus, their use in animal feeding needs to be investigated carefully. Feeding animals with insect-based diets affects their growth performances and the chemical composition of the derived products (fish fillets, meat, and eggs). Whether these effects can be considered positive or negative seems to depend to a great extent on the percentage of insects included in their diets and the chemical composition of the ingredients. The use of insect-based feeds has also shown a potential to improve the nutritional features and values of animal products and even to add new ones. Finally, many of the acceptance studies on the use of insects in feeds have focused mostly on the consumers' perception rather than on industry stakeholders (e.g., farmers). Future research should focus more on the farmers' perceptions on and market analyses of these innovative feeds. Even though it is likely that the upscaling of the insect sector will lead to a decrease in prices and an increase in market availability, it is still critical to understand the potential barriers and drivers for the implementation of insects as feeds from a production point of view.

Dietary Inclusion of Defatted Silkworm (Bombyx mori L.) Pupa Meal for Broiler Chickens at Different Ages: Growth Performance, Carcass and Meat Quality Traits

The present study was conducted to assess the effects of a 4% defatted silkworm (SWM-DEF) meal dietary incorporation into chickens’ diet at different growth stages on growth performances, carcass, and meat quality traits. A total of 90 Ross 308 one-day-old male broiler chickens were randomly allocated into 3 dietary groups of 5 replicated pens/diet (6 chickens/pen). One group was fed a standard soybean-based diet (C); group SWM1 consumed a starter diet (1−10 days of age) including 4% SWM-DEF and then the C diet up to slaughter (11−42 days of age); group SWM2 was fed with the C diet in the starter phase and the 4% SWM-DEF diet up to slaughter. Individual live weight and pen feed intake were determined at the end of each feeding phase: starter, grower, and finisher. Weight gain and FCR were then calculated. At 42 days of age, chickens were slaughtered and carcass traits determined. Leg and breast physico-chemical meat quality was also evaluated. Results confirmed that SWM-DEF could be a possible alternative feed source for chickens since growth performance, carcass, and meat physical traits were overall comparable in the three treatment groups. The feeding stage seemed to play a relevant impact on the sole meat protein content (SWM1 < SMW2 and C; p < 0.001). Concluding, the results available to date indicate that 4% SWM-DEF can be provided to chickens in different growth phases, and the choice of the inclusion period is more an industrial cost-benefit evaluation. From the scientific point of view, however, an administration in the grower-finisher phase rather than in the starter one provided the best meat nutritional quality. Further investigations should focus on the impact on meat fatty acids profile and sensory traits, which are of utmost importance for consumers.

Pre-Treatment of Fish By-Products to Optimize Feeding of Tenebrio molitor L. Larvae

Simple Summary

The rapid population growth and the consequent increase in demand for protein-rich foods pose a challenge for the food industry. On the other hand, resources are limited and production must be sustainable. Currently, insects are accepted by the European Union as sustainable and nutritive food for humans, consequently allowing the use of seven insect species, including Tenebrio molitor (Linnaeus, 1758). From a nutritional point of view, T. molitor is rich in protein (42.2–67.7%) with a good ratio of essential amino acids. However, their lipidic fraction lacks n−3 long chain polyunsaturated fatty acids (LCPUFAs), while it is rich in n−6 polyunsaturated fatty acids. This poses a problem for human intake, since the beneficial effect of n−3 polyunsaturated fatty acids and a low n−6/n−3 ratio on the prevention of cardiovascular inflammation and heart disease is well known. The present study is focused on the improvement of the fatty acid profile and proximal composition of T. molitor larvae through fish discard-based diets subjected to different pre-treatments to increase the fish-based diet intake.

Abstract

Fish discards are organic waste with high and good-quality protein levels, as well as a fatty acid profile rich in n−3 LCPUFAs, mainly eicosapentaenoic acid and docosahexaenoic acid. These discards can be used as food for Tenebrio molitor (Linnaeus, 1758) larvae, thus increasing the nutritional value of this insect. This study focused on increasing larval acceptance of fish through different pre-treatments of the diets provided, as well as increasing the accumulation of EPA and DHA in fish-fed larvae. Four different diets were prepared: control (broiler feed), DGF50: 50% dried ground fish (Pagellus bogaraveo, Brünnich, 1768) + 50% broiler feed, for different periods, FGF100: 100% fresh ground P. bogaraveo and DUF100: 100% dried whole unground P. bogaraveo. Growth, mortality, proximate composition, fatty acid profile and lipid nutritional indices were determined. Larvae fed with FGF100 displayed better results among treatments, doubling the initial weight, as well as increasing their protein level and decreasing fat levels. Regarding fatty acids, eicosapentaenoic acid and docosahexaenoic acid were only detected in larvae fed with a fish-based diet for a period longer than 5 days. These results show that pre-treatment of fish-based diets causes changes in the growth and compositional parameters of T. molitor larvae.

Codesign of Food System and Circular Economy Approaches for the Development of Livestock Feeds from Insect Larvae

Processes that utilise low-value wastes and convert them to high-value food ingredients systemically add value across commercial operations. Current common disposal options include use as animal feed, anaerobic digestion, composting, incineration, and the worst-case options of landfill and wastewater disposal. The pressure is acute with food manufacturers needing to align with the UN Sustainable Development Goals and reach targets of zero waste to landfill. This research identifies black soldier fly larvae as a bioreactor that converts most food waste into high-value feed materials. Production of larvae and the regulatory framework for their use as animal feed is being assessed in several nations. The requirement to understand the availability of feedstocks for larvae production and the capability to establish feedstock supply chains was tested in this study using geographical information system and life cycle assessment methodologies, providing new research insights for resource utilisation in a circular economy.