Insects as alternative feed for ruminants: comparison of protein evaluation methods

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.

Feed Efficiency and Growth Performance in Thai Beef Cattle Fed Cricket Meal as a Soybean Meal Replacement

Cricket (Gryllus bimaculatus) is a high-protein insect species with a favorable amino acid and fatty acid profile, widely recognized as an alternative to soybean meal in nonruminant diets. However, research on its use in ruminant nutrition remains limited, particularly regarding its effects on feed efficiency and performance. This study evaluated the impact of completely replacing soybean meal with cricket meal on feed intake, nutrient digestibility, rumen fermentation, microbial populations, and growth performance in Thai native beef cattle. Eight male Thai native beef cattle (150 ± 15 kg; ∼2 years old) were used in a completely randomized design with two dietary treatments (n = 4 per group). One group received a conventional soybean meal-based diet, while the other received a diet in which 100% of the soybean meal was replaced with cricket meal at an inclusion level of 12% of dry matter. Both diets were formulated to be isonitrogenous and isocaloric. Feed intake was similar between treatments. Crude protein digestibility was higher in the cricket meal group (67.5%) compared to the soybean meal group (63.7%; p = 0.04), while other digestibility parameters showed no differences. Blood metabolites, rumen fermentation characteristics, and microbial populations were unaffected by dietary treatment. Cattle fed the cricket meal-based diet showed greater average daily gain (+55.7%; p = 0.02) and a 32.9% improvement in feed conversion ratio (p = 0.02) compared to cattle fed the soybean meal-based diet. These results suggest that cricket meal can serve as a complete replacement for soybean meal in beef cattle diets, enhancing protein digestibility and growth performance without compromising rumen function.

Antioxidant, anti-inflammatory, anti-adipogenesis activities and proximate composition of Hermetia illucens larvae reared on food waste enriched with different wastes

The use of insects as a food source is not a new idea, but it has gained momentum in recent years due to the need for sustainable protein source in livestock feedstuffs and for more environmentally friendly organic waste treatment. In the case of black soldier fly larvae, Hermetia illucens, research has focused on their ability to convert organic waste into usable nutrients and their potential as a protein source for animal and human consumption. In this study, black soldier fly larvae were reared on raw food waste (FW) mixed with garlic peel waste (G) and hydronic growth media waste (H) and the proximate composition and bioactive potential of black soldier fly larvae extract (SFL) were compared. Analysis showed that protein content of SFL fed with G was 4.21% higher and lipid content was 9.93% lower than FW. Similar results were obtained for SFL fed with H. Antioxidant activity of SFL-G was higher than that of SFL-FW and SFL-H. SFL-G treatment exhibited enhanced anti-inflammatory and anti-adipogenesis activities as well compared to SFL-FW. Current results suggested that feeding black soldier fly larvae with food waste added with garlic peel and hydroponic growth media waste resulted in increased nutritional value, polyphenol content and bioactivity for SFLs. In this context, garlic peel waste-added food waste was suggested a promising substrate for black soldier fly larvae to obtain high-quality protein source with enhanced antioxidant, anti-inflammatory and anti-adipogenic potential.

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.

Maternal or post-weaning dietary fructo-oligosaccharide supplementation reduces stillbirth rate of sows and diarrhea of weaned piglets

Fructo-oligosaccharides (FOS) are well-known prebiotics that have the potential to improve sow reproductive performance and increase piglet growth. However, previous studies were observed in sole FOS-supplemented diets of sows or weaned piglets and did not consider the sow-to-piglet transfer effect on the performance and diarrhea rate of weaned piglets. This study explores the effects of dietary FOS supplementation on the reproductive performance of sows, and the effects of FOS supplementation at different stages on the growth performance and diarrhea rate of weaned piglets. A split-plot experimental design was used with sow diet effect in the whole plot and differing piglet diet effect in the subplot. Fifty-two multiparous sows (223.24 ± 14.77 kg) were randomly divided into 2 groups (0 or 0.2% FOS). The experiment lasted from day 85 of gestation to day 21 of lactation. Reproductive performance, glucose tolerance, placental angiogenesis, and intestinal flora of sows were assessed. At weaning, 192 weaned piglets were grouped in 2 × 2 factorial designs, with the main effects of FOS supplemental level of sow diet (0 and 0.2%), and FOS supplemental level of weaned piglet diet (0 and 0.2%), respectively. The growth performance and diarrhea rate of the weaned piglets were analyzed during a 28-d experiment. Maternal dietary supplementation of FOS was shown to reduce the stillbirth and invalid piglet rates (P < 0.05), improve the insulin sensitivity (P < 0.05) and fecal scores (P < 0.05) of sows, increase the abundance of Akkermansia muciniphila (P = 0.016), decrease the abundance of Escherichia coli (P = 0.035), and increase the isovalerate content in feces (P = 0.086). Meanwhile, the placental angiogenesis marker CD31 expression was increased in sows fed FOS diet (P < 0.05). Moreover, maternal and post-weaning dietary FOS supplementation reduced the diarrhea rate of weaned piglets (P < 0.05) and increased the content of short-chain fatty acids in feces (P < 0.05). Furthermore, only post-weaning dietary FOS supplementation could improve nutrient digestibility of weaned piglets (P < 0.05). Collectively, FOS supplementation in sows can reduce stillbirth rate, perinatal constipation, and insulin resistance, as well as improve placental vascularization barrier. Additionally, maternal and post-weaning dietary FOS supplementation reduced the diarrhea rate of weaned piglets, but only FOS supplementation in piglets alone at weaning stage could improve their nutrient digestibility.

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

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

Dietary water fly (Notonecta sp.) meal as an alternative protein source for sheep: Effects on performance, nutrient intake, nitrogen balance, and fermentation parameters

In this study, the inclusion of water fly (Notonecta sp., NT) meal was compared with conventional protein sources such as soybean meal (SBM) and fish meal (FM) in diets destined for sheep, with specific reference to growth performance, nutrient intake, nitrogen balance, and in vitro rumen fermentation parameters. For 21 days, 18 male Suffolk lambs were randomly assigned to three experimental diets fed: (1) SBM at 130 g/kg dry matter (DM), as a plant-based protein diet; (2) FM at 50 g/kg DM, as an animal-based protein diet; and (3) NT at 60 g/kg DM, as an insect-based protein diet, for ad libitum feed intake. DM intake was similar among the treatments. The digestibility of DM (p = 0.006) and organic matter (p = 0.002) in the NT group was lower than that of SBM. In vitro rumen fermentation data showed that there were no differences between the treatments for DM degradation and the production of microbial crude protein. No differences were observed among the treatments in terms of enteric methane production. The NT diet produced the lowest NH3-N at hours 12 and 24 (p = 0.032 and 0.021, respectively). Overall, the dietary inclusion of NT for fattening lambs could be an alternative feeding strategy without deleterious effects on animal performance.

Nutritional Value of Banded Cricket and Mealworm Larvae

Insect farming is more ecological than traditional animal farming, as it requires less water and contributes to lower greenhouse gas emissions. In our study, banded cricket (BC) and mealworm larvae (ML) were analyzed. The proximate composition was determined according to Association of Official Analytical Chemists. The mineral content was determined by colorimetry and mass spectrometry. Fatty acid methyl esters (FAMEs) were obtained from the samples and separated using a gas chromatography apparatus, coupled with a mass spectrometer. Our research confirmed that insects are a rich source of protein, with ML containing significantly more protein than BC (74.41 and 65.66 g/100 g dry matter (DM), respectively). In terms of the content of macrominerals, ML was significantly richer than BC, especially in terms of magnesium content (8.75 g/100 g DM). In terms of the content of saturated fatty acids, BC contained almost twice as much as ML (40.05 and 24.74% of the sum of fatty acids, respectively). EPA and DHA were only detected in the fat of BC. The presented results prove that both ML and BC can be good sources of protein both in human and companion animal diets. The component that is predominantly high in insects is fat, with a favorable fatty acid profile, especially in terms of polyunsaturated fatty acids. This study contributes new knowledge on the nutritional value of edible insects. In this research, we included three different nitrogen conversion factors for crude protein content. Our results partially confirm previous studies by other authors, although they provide new information on the content of fatty acids.

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.