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

Nutritional Value of the Larvae of the Black Soldier Fly (Hermetia illucens) and the House Fly (Musca domestica) as a Food Alternative for Farm Animals-A Systematic Review

Dietary alternatives using insect-based products as an alternative for farm animal nutrition have been the object of study due to the high nutritional value of these feeds and the costs related to both their production and consequently their commercialization. Thus, the use of flies, especially larvae, has a high content of proteins and lipids (fat), as well as minerals and essential nutrients for development and growth, directly impacting the production of these animals, whether meat or milk. Therefore, the objective of this study was to compile data from the literature on the nutritional value of adults and larvae of Black soldier (Hermetia illucens) and housefly (Musca domestica) as a dietary alternative for animal feed. The Prisma checklist was used. After reviewing the data found in the literature, following the systematic review, it was noted that studies emerge that larvae of black soldier flies and domestic flies of the order Diptera obtain essential sources in the nutrition of ruminants, in addition to obtaining rapid digestibility, thus adhering to reproduction with high nutritional content, due to incident levels of protein, lipids, and minerals in M. domestica and Lucilia sericata, making it a target for inclusion in the diet of farm animals. In addition, it is concluded that both species are studied for their sustainable potential as well as for offering greater economic and nutritional viability when compared to ingredients present in production animal feed.

Livestock feed resources used as alternatives during feed shortages and their impact on the environment and ruminant performance in West Africa: a systematic review

Ruminant feed is a major problem for the livestock sector in West African developing countries causing animal nutritional diseases, reducing ruminant production, and creating a massive ecological crisis through greenhouse gas emissions. Alternative feeds, which include agro-industrial by-products, fodder trees, crop residues, insects, fodder legumes, algae, and pulses, constitute enormous feed resources for livestock in Africa. This study was conducted in accordance with the methodological recommendations of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). We conducted a literature search using Google Scholar, Web of Science, and Scopus to identify documents related to alternative ruminant feeds using the following keywords: alternative feeds, ruminant products, environmental impacts, and West Africa. Those that met the inclusion criteria were included, resulting in 44 articles published between 2013 and 2023. These studies included 45 alternative feeds divided into six groups, including agro-industrial by-products (48.89%), followed by fodder trees (17.78%), crop residues (13.33%), insects (8.89%), fodder legumes (6.67%) and seaweeds (4.44%). Our results revealed that alternative feed resources and their effects on ruminant's performances and environment are poorly known in West Africa, which limits their inclusion in rations and sometimes leads to their misuse. Future research should focus on these aspects in order to make efficient use of these resources to improve ruminant milk and meat production.

Fermented Protaetia brevitarsis Larvae Ameliorates Chronic Ethanol-Induced Hepatotoxicity in Mice via AMPK and TLR-4/TGF-β1 Pathways

This study evaluated the hepatoprotective effect of fermented Protaetia brevitarsis larvae (FPB) in ethanol-induced liver injury mice. As a result of amino acids in FPB, 18 types of amino acids including essential amino acids were identified. In the results of in vitro tests, FPB increased alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities. In addition, FPB treatment increased cell viability on ethanol- and H2O2-induced HepG2 cells. FPB ameliorated serum biomarkers related to hepatoxicity including glutamic oxaloacetic transaminase, glutamine pyruvic transaminase, total bilirubin, and lactate dehydrogenase and lipid metabolism including triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. Also, FPB controlled ethanol metabolism enzymes by regulating the protein expression levels of ADH, ALDH, and cytochrome P450 2E1 in liver tissue. FPB protected hepatic oxidative stress by improving malondialdehyde content, reduced glutathione, and superoxide dismutase levels. In addition, FPB reversed mitochondrial dysfunction by regulating reactive oxygen species production, mitochondrial membrane potential, and ATP levels. FPB protected ethanol-induced apoptosis, fatty liver, and hepatic inflammation through p-AMP-activated protein kinase and TLR-4/NF-κB signaling pathways. Furthermore, FPB prevented hepatic fibrosis by decreasing TGF-β1/Smad pathway. In summary, these results suggest that FPB might be a potential prophylactic agent for the treatment of alcoholic liver disease via preventing liver injury such as fatty liver, hepatic inflammation due to chronic ethanol-induced oxidative stress.

Black Soldier Fly Larva Oil in Diets with Roughage to Concentrate Ratios on Fermentation Characteristics, Degradability, and Methane Generation

Currently, the scarcity of high-quality, expensive animal feed is a primary factor driving up the cost of animal husbandry. As a result, most researchers have focused on improving the potential of using alternative feed resources derived from the black soldier fly larva. In particular, the utilization of oil from black fly larvae is a byproduct of the industry. The aim of this study was to investigate the influence of black soldier fly larva oils and the proportion of roughage-to-concentrate ratios on gas kinetics, rumen characteristics, degradability, and mitigate CH4 production by using in vitro gas production techniques. The in vitro investigation used a completely randomized design (CRD) with a 2 × 4 factorial arrangement. The level of R:C ratios (60:40 and 40:60) were factor A, while BSFO levels (0, 2, 4, and 6% of DM) were factor B. Under this investigation, the combined impact of R:C ratio and BSFO on the kinetics of gas and accumulative gas production was found to be significant (p < 0.01). After 4 h of incubation, the pH and ammonia-nitrogen (NH3-N) concentration were found to be impacted by the inclusion of BSFO levels at different R:C-ratios (p < 0.01). Moreover, after 4 and 8 h of incubation, supplementing the BSFO at 4% with the level of R:C ratio at 40:60 resulted in a significant reduction in the amount of CH4 in the rumen (p < 0.05). However, the inclusion of BSFO levels at different R:C ratios had no effect on the degradability of DM after 12 and 24 h of incubation (p > 0.05), whereas increasing the concentration of BSFO in concentrate at 6% reduced the DM degradability after 24 h of incubation (p < 0.05). Furthermore, adding BSFO to the diet at various R:C ratios enhanced the propionate (C3) concentration, with the highest level observed with the level of R:C ratio at 40:60 and 4% BSFO inclusion (p < 0.05). To summarize, the addition of BSFO at 4% with a 40:60 of R:C ratio increased C3 levels, decreased CH4 emission, and preserved DM degradability. A R:C ratio of 40:60 could improve the total volatile fatty acids and digestibility. Moreover, the inclusion of 6% BSFO at different R:C ratios lowered the in vitro dry matter digestibility, in vitro organic matter digestibility, NH3-N, and protozoal populations.

Methane emission, intake, digestibility, performance and blood metabolites in sheep supplemented with cupuassu and tucuma cake in the eastern Amazon

The use of co-products as a feed supplement for ruminants makes livestock sustainable and optimizes the use of available areas and animal performance. Furthermore, when cakes are used, the residual fat composition can influence ruminal metabolism and methane (CH4) production. This study aimed to assess the effects of a diet containing cupuassu (CUP; Theobroma grandiflorum) and tucuma (TUC; Astrocaryum vulgare Mart.) cakes on intake, digestibility, serum metabolites, performance, and CH4 emissions in confined sheep in the Amazon. Approximately 28 animals, Dorper-Santa Inês, castrated, with an average initial live weight (ILW) of 35 ± 2.3 kg, were distributed in metabolic cages, in a completely randomized design, with four treatments and seven replications: (1) Control (C40), without the addition of Amazonian cake and with 40 g of ether extract (EE)/kg of dietary dry matter (DM); (2) CUP, the inclusion of the CUP cake and 70 g of EE/kg; (3) TUC, the inclusion of the TUC cake and 70 g of EE/kg; and (4) Control (C80), without the addition of Amazonian cake and with 80 g of EE/kg of dietary DM, with roughage to concentrate ratio of 40:60. The use of the TUC cake as a feed supplement reduced the intake of DM, crude protein (CP), and EE compared to the inclusion of the CUP cake (p < 0.05); however, it increased the intake of neutral detergent fiber (NDF) by 32% (p < 0.01). The highest averages of DM (732 g/kg) and CP (743 g/kg) digestibility were presented in C40, while the highest digestibility of NDF was presented in TUC (590 g/kg). Albumin levels stayed above and protein levels were below the reference values, and the C40 diet also obtained below results for cholesterol, triglycerides and High Density Lipoprotein (HDL) (P < 0.05). Sheep fed CUP (91 g) and TUC (45 g) had lower daily weight gains (DWGs) than those fed with diets without the inclusion of cakes (C40 = 119 g; C80 = 148 g), and feed efficiency (FE) was also lower in CUP (84) and TUC (60) diets than in C40 (119) and C80 (137) diets. CH4 emissions were lower in animals fed TUC (26 L/day) and higher in C40 (35 L/day); however, TUC resulted in higher CH4 emissions in grams/body live weight (BW) gain/day (353 g/BW/day) vs. 183 g/BW/day (C40), 157 g/BW/day (C80), and 221 g/BW/day (CUP). The supplementation with cakes did not improve intake, digestibility and performance, did not compromise blood metabolites and did not reduce the enteric CH4 emission in confined sheep in the Amazon; however, the use of CUP cake showed similar results to the control treatments and did not increase CH4 emissions, as occurred with the inclusion of TUC cake.

Micro- and Macro-Algae Combination as a Novel Alternative Ruminant Feed with Methane-Mitigation Potential

This study was conducted to provide alternative high-quality feed and to reduce methane production using a mixture of the minimum effective levels of Euglena gracilis, EG, and Asparagopsis taxiformis, AT. This study was performed as a 24 h in vitro batch culture. Chemical analysis demonstrated that EG is a highly nutritive material with 26.1% protein and 17.7% fat. The results showed that the supplementation of AT as a feed additive at 1 and 2.5% of the diet reduced methane production by 21 and 80%, respectively, while the inclusion of EG in the diet at 10 and 25% through partially replacing the concentrate mixture reduced methane production by 4 and 11%, respectively, with no adverse effects on fermentation parameters. The mixtures of AT 1% with both EG 10% and EG 25% had a greater reductive potential than the individual supplementation of these algae in decreasing methane yield by 29.9% and 40.0%, respectively, without adverse impacts on ruminal fermentation characteristics. These results revealed that the new feed formulation had a synergistic effect in reducing methane emissions. Thus, this approach could provide a new strategy for a sustainable animal production industry.

Full-fat insect meals in ruminant nutrition: in vitro rumen fermentation characteristics and lipid biohydrogenation

BACKGROUND

The most used protein sources in ruminant nutrition are considered as having negative impacts in terms of environmental sustainability and competition with human nutrition. Therefore, the investigation of alternative and sustainable feedstuffs is becoming a priority in ruminant production systems.

RESULTS

This trial was designed to evaluate eight full-fat insect meals (Acheta domesticus - ACD; Alphitobius diaperinus - ALD; Blatta lateralis - BL; Gryllus bimaculatus - GB; Grylloides sygillatus - GS; Hermetia illucens - HI; Musca domestica - MD; and Tenebrio molitor - TM) as potential protein and lipid sources in ruminant nutrition. Fermentation parameters and fatty acids (FA) of rumen digesta after 24-h in vitro ruminal incubation of the tested insect meals were measured and compared with those of three plant-based meals (soybean meal, rapeseed meal and sunflower meal) and fishmeal (FM). Similarly to FM, the insect meals led to a significantly lower total gas production (on average, 1.75 vs. 4.64 mmol/g dry matter-DM), methane production (on average, 0.33 vs. 0.91 mmol/g DM), volatile FA production (on average, 4.12 vs. 7.53 mmol/g DM), and in vitro organic matter disappearance (on average, 0.32 vs. 0.59 g/g) than those observed for the plant meals. The insect meals also led to lower ammonia of rumen fluid, when expressed as a proportion of total N (on average, 0.74 vs. 0.52 for the plant and insect meals, respectively), which could be an advantage provided that intestinal digestibility is high. Differences in ruminal fermentation parameters between the insect meals could be partially explained by their chitin, crude protein and ether extract contents, as well as by their FA profile. In particular, high content of polyunsaturated FA, or C12:0 (in HI), seems to partially inhibit the ruminal fermentations.

CONCLUSIONS

The tested full-fat insect meals appear to be potentially an interesting protein and lipid source for ruminants, alternative to the less sustainable and commonly used ones of plant origin. The FA profile of the rumen digesta of ACD, ALD, GB, GS and TM, being rich in n-6 polyunsaturated FA, could be interesting to improve the quality of ruminant-derived food products.

Defatted silkworm pupae meal as an alternative protein source for cattle

Silkworm pupae meal (SWP) is a protein-rich by-product of the silk reeling industry, available in a significant quantity. However, there has been little and insignificant research into the use of SWP in ruminants to date. In this view, the present study was conducted in two phases to evaluate the effect of different inclusion levels of defatted silkworm pupae meal (DSWP) on rumen fermentation, microbial protein synthesis and nutrient utilisation in cattle fed on finger millet straw (FMS)-based diet. Four isonitrogenous concentrate mixtures (CM) were prepared with DSWP replacing soybean meal (SBM) protein at 0 (T0), 10 (T1), 20 (T2) and 30% (T3). In phase I, a rumen fermentation experiment was conducted in a 4 × 4 Latin square design using four crossbred steers to study the effect of different levels of DSWP on rumen fermentation. No significant difference (P > 0.05) was observed in rumen fermentation parameters such as pH, ammonia nitrogen (NH₃-N) and total volatile fatty acids (VFA) among the experimental groups. In phase II, the digestibility trial was conducted in 20 crossbred cattle (311.2 ± 4.81 kg), which were divided into four experimental groups of five animals each in a completely randomised design to study the effect of different rations (T0, T1, T2, T3) on microbial protein synthesis and nutrient utilisation. The intake and digestibility of nutrients, excretion of urinary purine derivatives and microbial protein synthesis were not significantly different among the experimental groups. In addition, feeding DSWP revealed no significant (P > 0.05) change in the blood biochemical parameters of animals. Furthermore, at the same price as SBM, DSWP provides two units more crude protein. Therefore, the results of the present study indicated that DSWP can be incorporated into the ration of cattle up to 30% by replacing SBM without affecting rumen fermentation pattern and nutrient utilisation.

Road to The Red Carpet of Edible Crickets through Integration into the Human Food Chain with Biofunctions and Sustainability: A Review

The Food and Agriculture Organization of the United Nations (FAO) estimates that more than 500 million people, especially in Asia and Africa, are suffering from malnutrition. Recently, livestock farming has increased to supply high-quality protein, with consequent impact on the global environment. Alternative food sources with high nutritive values that can substitute livestock demands are urgently required. Recently, edible crickets have been promoted by the FAO to ameliorate the food crisis. In this review, the distribution, nutritive values, health-promoting properties (antioxidant, anti-inflammatory, anti-diabetic and anti-obesity), safety, allergenicity as well as the potential hazards and risks for human consumption are summarized. Cricket farming may help to realize the United Nations sustainable development goal No. 2 Zero Hunger. The sustainability of cricket farming is also discussed in comparison with other livestock. The findings imply that edible crickets are safe for daily intake as a healthy alternative diet due to their high protein content and health-promoting properties. Appropriate use of edible crickets in the food and nutraceutical industries represents a global business potential. However, people who are allergic to shellfish should pay attention on cricket allergy. Thus, the objective of this review was to present in-depth and up-to-date information on edible crickets to advocate and enhance public perception of cricket-based food.

Cricket Meal (Gryllus bimaculatus) as a Protein Supplement on In Vitro Fermentation Characteristics and Methane Mitigation

Simple Summary

Protein sources of high quality and sustainability are found in insects. In many regions, insects are a primary food source, such as in Africa, South America, Asia, and Oceania. Insects are considered promising alternative feed sources, in particular as a source of protein. The use of edible insects as high-protein sources is widespread, and cricket has been proved to be a potential food and feed insect species. Cricket (Gryllus bimaculatus) also contain 54.10% crude protein, 6.90% crude fiber, 26.90% fat, and 78.90% total digestible nutrient, as well as a variety of essential amino acids, including methionine, lysine, histidine, valine, and leucine. In addition, insects have been investigated as a source of protein in diets of poultry, swine, and fish. However, there are currently little data on the utilization of insects as ruminant feed. The objective of this experiment was to conduct the effects of Cricket meal (Gryllus bimaculatus) (CM) as a protein replacement for soybean meal on in vitro fermentation end products, gas production, nutrient degradability, and methane mitigation.

Abstract

The aim of this work was to conduct the effects of cricket (Gryllus bimaculatus) meal (CM) as a protein supplement on in vitro gas production, rumen fermentation, and methane (CH₄) mitigation. Dietary treatments were randomly assigned using a completely randomized design (CRD) with a 2 × 5 factorial arrangement. The first factor was two ratios of roughage to concentrate (R:C at 60:40 and 40:60), and the second factor was the level of CM to replace soybean meal (SBM) in a concentrate ratio at 100:0, 75:25, 50:50, 25:75, and 0:100, respectively. It was found that in vitro DM degradability and the concentration of propionic (C₃) were significantly increased (p < 0.05), while the potential extent of gas production (a + b), acetate (C₂), acetate and propionate (C₂:C₃) ratio, and protozoal population were reduced (p < 0.05) by lowering the R:C ratio and the replacement of SBM by CM. In addition, rumen CH₄ production was mitigated (p < 0.05) with increasing levels of CM for SBM. In this study, CM has the potential to improve rumen fermentation by enhancing C₃ concentration and DM degradability, reduced methane production, and C₂:C₃ ratio. The effects were more pronounced (p < 0.05) at low levels of roughage.