Rearing black soldier flies: cultivating primary students’ scientific habits of mind

The purpose of this experiment was to evaluate the effects of dietary replacement of fish meal by black soldier fly (BSF) larvae on growth performance, blood profiles, immune response, and diarrhea incidence in weaning pigs. A total of 160 weaning ([Yorkshire × Landrace]) × Duroc) pigs (7.47 ± 0.02 kg body weight [BW]) were assigned to four treatments based on sex and initial body weight, with five replicates of eight pigs per pen in a randomized complete block design (RCBD). Experimental diets with black soldier fly (BSF) larvae replaced fish meal (FM) at 0, 25, 50, and 100% for phase I (0 to 2 weeks). Phase II (3 to 4 weeks) were as follows: 1) Control: corn‒soybean-based diet containing FM 4%, 2) BSF25: corn‒soybean-based diet containing FM 3% and BSF larvae 1%, 3) BSF50: corn‒soybean-based diet containing FM 2% and BSF larvae 2%, 4) BSF100: corn‒soybean-based diet containing BSF larvae 4%. The study found no significant differences among the treatment groups in BW and ADG during the experimental period. However, an increased tendency of ADFI was observed (linear, p=0.09), and G:F ratio tended to decrease as the replacement rate of fish meal with BSF larvae increased (linear, p=0.06). During phase I, creatinine concentration decreased linearly as BSF larvae level increased (linear, p=0.02). During phase II, a linear response was observed in the change of glucose concentration as an increase in BSF larvae level (linear, p=0.02). Meanwhile, pigs fed with increasing BSF larvae levels showed increased albumin and total protein concentration trends (linear, p=0.05, p=0.05). Defatted BSF larvae can replace up to 50% of FM in weaning pig diets without detrimental effects on performance, blood metabolites, or immune response.These reassuring findings suggest that BSF larvae could be a sustainable and effective replacement for fish meal in pig diets.

Black soldier fly (Hermetia illucens) larvae are a promising source of protein and lipid for animal feeds. The nutritional composition of the BSF larvae depend partly on the composition of the feeding medium. The BSF lipid profile in part mimics the feeding media lipid profile, and micronutrients, like minerals and vitamins, can readily accumulate in black soldier fly larvae. However, investigative studies on bioconversion and accumulation of nutrients from media to black soldier fly larvae are scarce. Here we show that inclusion of the brown algae Ascophyllum nodosum in the substrate for black soldier fly larvae can introduce valuable nutrients, commonly associated with the marine environment, into the larvae. The omega-3 fatty acid eicosapentaenoic acid (20:5n-3), iodine and vitamin E concentrations increased in the larvae when more seaweed was included in the diet. When the feeding media consisted of more than 50% seaweed, the larvae experienced poorer growth, lower nutrient retention and lower lipid levels, compared to a pure plant based feeding medium. Our results confirm the plasticity of the nutritional make-up of black soldier fly larvae, allowing it to accumulate both lipid- and water-soluble compounds. A broader understanding of the effect of the composition of the feeding media on the larvae composition can help to tailor black soldier fly larvae into a nutrient profile more suited for specific feed or food purposes.

Context Black soldier fly larvae are a promising alternative ingredient in poultry feed. They might be able to replace soybean and fishmeal because the have high concentrations of protein and fat, and are also rich in vitamins and minerals, and because partial replacement of soybean and total replacement of fishmeal produce no adverse effect on the growth performance of village chickens. Therefore, they are a suitable replacement for these traditional ingredients in poultry feed. Aims This study determines the nutritive values of black soldier fly larvae and evaluates the effects of feeding diets containing black soldier fly larvae on the growth performance of village chickens. Methods Samples of black soldier fly larvae were subjected to proximate analysis before a total of 280 1-day-old village chicks were randomly divided into four groups. All groups were fed a basal diet with partial replacements of corn and soybean with black soldier fly larvae at 0% (Control), 5% (T1), 10% (T2) and 15% (T3) for 70 days. Each treatment group consisted of seven replicates, with 10 birds per replicate. The bodyweights, bodyweight gains and feed conversion rates were determined. Key results Dry rendered black soldier fly larvae contained 773.0 ± 0.08 g/kg dry matter, 36.1 ± 0.09 g/kg ash, 408.8 ± 0.28 g/kg crude protein, 283.0 ± 0.16 g/kg ether extract and 40.9 ± 0.44 g/kg crude fibre. The larvae also contained 2.041 MJ/kg of metabolisable energy, 20.4 g/kg of calcium and adequate concentrations of vitamins. The feeding trial showed an average bodyweight gain of 1231.45 ± 23.37 g and feed conversion ratio of 2.03 ± 0.15, which were most efficient with Diet T3. Conclusions Inclusion of 15% black soldier fly larvae in diets can enhance the growth performance of village chickens without adverse effects. Implications Partial replacement of soybean and total replacement of fishmeal in the diet of chickens by black soldier fly larvae are not affecting the growth performance of village chickens but might reduce the feed cost.

The unreasonable disposal of polyurethane leads to resource waste and environmental pollution. Black soldier fly (Hermetia illucens) larvae facilitate the bioconversion of various organic wastes, but the degradation of polyurethane by black soldier fly larvae and the response mechanism of black soldier fly larvae gut microorganisms remain unclear. In this study, a s tandard diet (CK), polyurethane foam, and starvation were applied to rear black soldier fly larvae. We found that 82% of black soldier fly larvae survived, and their weight increased by 19 mg per larva after 16 d of feeding with polyurethane foam and water. The consumption rate of polyurethane was 0.35 mg/day per larva, and the cellular texture of polyurethane foam was damaged. X-ray photoelectron spectrometer and Fourier transform infrared spectroscopy suggested that ester, ether and urethane bonds were cracked. Analysis of gut microorganisms indicated that Dysgonomonas, Morganella, and Klebsiella were the most abundant genera in CK, while Providencia, Scatolibacter, and Chryseobacterium were the most abundant genera in polyurethane, indicating that gut microbial community could respond to a harsh environment and offer a stable survival and adaption strategy for black soldier fly larvae. In addition, a polyurethane-degradation strain from black soldier fly larvae gut named Delftia sp. A2 was isolated, suggesting the potential of gut microorganisms to discover other functional strains. In summary, we found that black soldier fly larvae could survive and gain weight with the polyurethane as the sole substrate and polyurethane consumption influenced gut microbial community.

In recent years, interest in the larvae of black soldier fly (BSF) (Hermetia illucens) as a sustainable protein resource for livestock feed has increased considerably. However, knowledge on the nutritional and physiological aspects of this insect, especially compared to other conventional farmed animals is scarce. This review presents a critical comparison of data on the growth potential and efficiency of the BSF larvae (BSFL) compared to conventional monogastric livestock species. Advantages of BSFL over other monogastric livestock species includes their high growth rate and their ability to convert low-grade organic waste into high-quality protein and fat-rich biomass suitable for use in animal feed. Calculations using literature data suggest that BSFL are more efficient than broilers, pigs and fish in terms of conversion of substrate protein into body mass, but less efficient than broilers and fish in utilization of substrate gross energy to gain body mass. BSFL growth efficiency varies greatly depending on the nutrient quality of their dietary substrates. This might be associated with the function of their gastrointestinal tract, including the activity of digestive enzymes, the substrate particle characteristics, and their intestinal microbial community. The conceived advantage of BSFL having an environmental footprint better than conventional livestock is only true if BSFL is produced on low-grade organic waste and its protein would directly be used for human consumption. Therefore, their potential role as a new species to better close nutrient cycles in agro-ecological systems needs to be reconsidered, and we conclude that BSFL is a complementary livestock species efficiently utilizing organic waste that cannot be utilized by other livestock. In addition, we provide comparative insight into morpho-functional aspects of the gut, characterization of digestive enzymes, gut microbiota and fiber digestion. Finally, current knowledge on the nutritional utilization and requirements of BSFL in terms of macro- and micro-nutrients is reviewed and found to be rather limited. In addition, the research methods to determine nutritional requirements of conventional livestock are not applicable for BSFL. Thus, there is a great need for research on the nutrient requirements of BSFL.

The emergence of black soldier fly larvae (BSFL) as one among the vital tools for generating circular economy has enabled its use in several applications such as biorefining, valorization of waste management, treatment of industrial by-products, and bioconversion of agro-industrial residues. The ability of BSFL to assimilate chemical constituents of interest from the feed substrate and easily recover them from the insect matrix gives it a bio-reactor like characteristic. The primary unit operation after insect harvesting is the devitalization technique employed, and further processing of BSFL depends on the end application of the insect product. Conventional drying, microwave drying, scalding, blanching, microwave-assisted subcritical condition, and freezing as devitalization techniques to euthanize BSFL was executed. The impact of the devitalization techniques on the BSFL oil, protein, antioxidant, and chitin fractions was evaluated. The crude lipid yield, fatty acid profile and lipid class composition were investigated. The fatty acid profile was uniform for BSFL fractions devitalized by different techniques, and triacylglycerides were the primary lipid class in the oil fraction. The protein solubility of the defatted BSFL flour in different pH was determined. The protein quality parameters such as protein dispersibility index, urease activity index, and molecular weight distribution of the soluble protein fractions were analyzed. The frozen BSFL fraction displayed the highest protein solubility in all pH range considered, protein dispersibility index (PDI) and protein solubility (PS) was 52.86 ± 2.99% and 83.94 ± 2.96%, respectively. The aminogram of dry defatted BSFL flour, BSFL concentrate and isolate were recorded and the nitrogen-to-protein conversion (Kp) value was determined for these fractions. The antioxidant capacity of water-soluble bioactive compounds of BSFL was evaluated. Radical scavenging capacity and total polyphenol content of the BSFL fraction devitalized by microwave-assisted subcritical treatment and freezing displayed higher values when compared to other BSFL fractions. The chitin fractions were characterized by determining the degree of acetylation. Devitalization techniques strongly influence and impact the major BSFL constituents except for chitin and selection of the method should depend on the end application of the insect product. The microwave-assisted subcritical treatment proved to be an efficient devitalization technique. Whereas, freezing being a non-thermal treatment has a few limitations. Graphic abstract

Organic waste is one of the major environmental problems, and the black soldier fly (Hermetia illucens) larvae can help decompose organic waste. Therefore, this research is interested in studying organic fertilizers' growth, nutritional value, and nutrient contents from the residue of black soldier fly larvae. Four experimental sets of plastic buckets containing organic wastes, i.e., pineapple peels, banana peels, durian peels, and vegetable scraps, were used to trap the black soldier flies and observe the spawning and the number of egg clusters. After that, the 4-day-old black soldier fly larvae were incubated in plastic boxes using different foods for the same duration. Three replicates of the experiment were performed, recording the growth period and size of the soldier fly larvae. The study found that the life cycle of the black soldier fly was divided into 5 stages: egg, larval, prepupal, pupal, and adult stages, in 47–67 days. The black soldier fly larvae fed pineapple peels both in the larval and prepupal stages were the largest, while the larvae fed with durian peels entered the larval stage the fastest. Subsequently, 100 g of fresh black soldier fly larvae samples from four experimental sets were analyzed for nutritional value. It was found that fresh black soldier fly larvae had protein contents of 9.25–10.69 g/100 g and a fat content of 3.29–15.90 g/100 g, which were suitable for use as an ingredient in animal feed to reduce production costs. Then, 100 g of the frass of the black soldier fly larvae fed with durian peels was collected for analysis of the essential nutrients for plants, i.e., nitrogen, phosphorus, and potassium, at about 2.46%, 2.77%, and 3.14%, respectively, which are suitable for use as organic fertilizers for soil amendments.

Effects of feeding unprocessed whole black soldier fly (Hermetia illucens) larvae on performance, biochemical profile, health status, egg quality, microbiome and metabolome patterns of quails

Meal of black soldier fly larvae (BSFL), which requires extraction of protein and fat, is a novel protein source for poultry, while unprocessed whole BSFL could even directly be fed to chickens. Newly hatched Ross-308 chicks (n = 252) received whole BSFL at 10% (L10), 20% (L20), or 30% (L30) of voluntary feed intake (FI) of control chickens (CON) that received no BSFL but only age-specific diets (n = 63 birds / group) for 42 days (d). Acceptance and nutrient and energy intake of birds by BSFL and FI were calculated. Plasma metabolites were measured using an automatic enzymatic analyzer and immunoglobulins with ELISA. Depending on the variable, data were analyzed using ANOVA or repeated measures ANOVA to address treatment, time and interaction effects. Birds consumed all offered larvae. With the exception of d1, time spent by birds eating their daily portion of larvae (TSL, min/pen) did not differ among the larvae supply groups (P = 0.982). The L10 had a higher larvae eating rate (LER) that is, speed of larvae intake than did L20 and L30 (P < 0.05), implying increased competition for less available BSFL. The ratio of LER to feed eating rate (FER) was greater than 50 fold change difference (FCD), indicating a strong interest of chickens in BSFL over regular feed. Whole BSFL intake up to 30% of voluntary FI did not adversely affect broiler growth (P > 0.05). The L30 had lower total dry matter and metabolizable energy intakes (P < 0.05), although total fat intake was higher in L30 than in CON (P < 0.05). Compared with CON, 30% whole BSFL increased dietary protein-to-energy ratios, plasma uric acid and serum alkaline phosphatase concentrations (P < 0.05). We conclude that whole BSFL can be included in broiler rations up to 20% without negatively affecting growth performance and nutrient conversion efficiency, whereas a higher proportion is associated with lower protein utilization efficiency, possibly due to lower total energy intake.

Can black soldier fly (BSF) larvae be a protein substitute for managing adverse food reactions (AFRs) in dogs, specifically those with dermatitis? We evaluated BSF larvae's safety, tolerance, and effectiveness as a novel protein source in dogs with AFRs. Sixteen dogs, including eight healthy controls and eight diagnosed with AFRs, were fed a diet containing BSF larvae for four weeks. Skin conditions, including dermatological lesions and Pruritus Visual Analog Scale (PVAS) scores, and gastrointestinal signs, including relevant clinical signs, stool consistency, and hematological and biochemical parameters, were monitored. No significant gastrointestinal side effects were observed. The control and AFRs groups maintained stable body weights, while stool consistency scores did not change significantly. Moreover, skin reaction data obtained before the study were collected through interviews with the owners. The mean PVAS scores in the AFRs group were significantly higher (p < 0.05) during the self-control period (6.0 ± 1.6) when compared with other periods. However, no significant differences (p > 0.05) were observed between the pre-study baseline (2.0 ± 1.1) and scores at 2 weeks (2.3 ± 1.5) and 4 weeks (2.4 ± 1.2) of feeding with BSF-based food, which indicated that BSF larvae did not exacerbate pruritic symptoms. Hematology and blood chemistry remained within normal ranges in all dogs, indicating no adverse effects on overall health. BSF larvae were well tolerated by AFR-affected and control dogs, with no adverse clinical outcomes. The findings suggest that BSF larvae may offer a better, sustainable alternative protein source for managing AFRs in dogs, particularly in those on hypoallergenic diets. Further long-term studies are needed to confirm these results and assess the broader implications of BSF larvae diets on canine health.

The bioconversion of organic solid waste utilizing Black Soldier Fly (BSF) larvae was used to reduce the unstable domestic supply of feed protein in Indonesia due to currency change dynamics. BSF larvae are a well-known bioconversion agent capable of producing high protein content in their body mass. Therefore, this research aims to conduct a small-scale bioconversion process of domestic and industrial organic solid wastes to produce dry BSF larvae as a protein source for chicken and fish culture. The research was held at Bogor, Indonesia, from March-June 2021, where organic solid waste from a restaurant was bioconverted by BSF larvae in a biopond. After two weeks, the BSF larvae were harvested, dried, and milled to produce the powder. Based on SNI 7548:2009, the quality of pellets from BSF larvae and pupae was appropriate, except for the parameters of fat content in pellet A and water and ash content in pellet B. The results showed that fish pellets mixed with 20% protein flour affected the weight growth of Pangasius sp. Furthermore, when dried BSF larvae powder was applied to one-day-old chickens, they grew somewhat quicker than the standard feed menu. Therefore, organic solid waste, when appropriately managed, produces feed protein.

Owing to an increasing world population and a rising demand in protein for food and feed, alternative protein sources are needed. In addition, existing food and protein supplies such as wild and farmed fish need to be secured. Insects and more specifically the black soldier fly (BSF;Hermetia illucens) larvae, are discussed as an alternative animal protein source and a potential fish meal (FM) replacer in aquaculture. They can be sustainably reared on biogenic residues. In a literature study, the technical potential of occurring biogenic residues in Germany for the production of BSF larvae is estimated and their suitability as a FM replacement in aquafeed for the production of rainbow trout is evaluated. According to literature, up to 50% of FM can be substituted by BSF larvae meal in the feed of rainbow trout. For the annual German rainbow trout production of 8,466 t, 2,699 t BSF larvae meal (40.7% protein d.m.) is required to replace 1,556 t FM (70.9% protein d.m.). The demand for biogenic residues to feed the BSF larvae amounts to 22,942 t (d.m.). A large amount of biogenic residues occurring in Germany, such as forestry residues, animal excrements, straw and the biogenic fraction of municipal waste, have too poor nutrient contents or are inapplicable due to legal restrictions as feed for farmed animals. However, an alternative utilisation of approximately 1.26 Mt (d.m.) of biogenic industrial residues by far exceeds the demand for BSF larvae feed. Further investigations are needed on the environmental impact and profitability of using biogenic residues for BSF larvae production and competing utilisation pathways as well as of using resulting BSF larvae meal as FM replacement in feed for rainbow trout. Graphical abstract – Annual technical potential of a biogenic residue-based production of black soldier fly (BSF) larvae as aquafeed for farmed rainbow trout in Germany (M = million, based on dry weight unless indicated otherwise).

This study evaluated survival, growth performance, digestive enzyme activities, intestinal histology, and antioxidant enzyme activities of the Pacific white shrimp (Litopenaeus vannamei), which were fed with five different diets, containing 0%, 25%, 50%, 75%, and 100% fresh black soldier fly larvae (BSFL), respectively, to replace commercial feed at an equal wet weight. The cultured experiment was lasted for 45 days, and the results showed that survival rate (SR), final body weight (FBW), and weight gain (WG) were negatively related with the replacement rate of fresh BSFL in the diet, where the maximum value was found in the BSFL 25% group, while the minimum value appeared in the BSFL 100% group. When BSFL replacement level was equal to or above 75%, the SR, FBW and WG were significantly decreased. However, hepatosomatic index (HSI) was increased with the increasing BSFL replacement level, which was significantly higher in BSFL 75% and BSFL 100% groups than the other groups. No significant differences on hepatopancreatic amylase and lipase activities of the shrimp were observed among all the groups. However, compared with the control group, protease activity in hepatopancreatic of the shrimp was significantly higher when up to 25% of commercial feed was replaced. The histological structure of the intestine gradually changed pathologically, such as tissue disruption, with increasing proportion of fresh BSFL in the diets. A significant reduction in intestinal fold height was found in the BSFL 100% group, and a decreased thickness of intestinal muscular was also observed in all treatment groups. The serum SOD and GSH-PX activities of shrimp in all treatment groups were significantly higher than that of the control group. In conclusion, replacing commercial feed up to 50% with fresh BSFL could be feasible for L. vannamei farming when growth performances, digestive enzyme activities, intestinal histology, and antioxidant enzymes were being considered.

Treatment of landfill leachate by black soldier fly (Hermetia illucens L.) larvae and the changes of intestinal microbial community

The growth and development of black soldier fly, Hermetia illucens (L.), larvae fed chicken manure inoculated with bacteria isolated from black soldier fly larvae and associated larval feed was evaluated. Four strains of Bacillus subtilis were evaluated. B. subtilis strains S15, S16, S19, were isolated from the gut of black soldier fly larvae. B. natto strain D1 was isolated from the diet fed to black soldier fly larvae. These bacteria were added individually into nonsterile 200 g fresh hen manure at 10(6) cfu/g and homogenized. Treated manure was then inoculated with 4-d old black soldier fly larvae. Prepupal weight ranged from 0.0606 g in the control to 0.0946 g in manure treated with the S15 strain. Larval survivorship to the prepupal stage in all treatments ranged from 98.00 ± 2.65% to 99.33 ± 1.15%. Prepupal survivorship to the pupal stage ranged from 91.92 ± 1.87% to 97.95 ± 1.03%. Adult emergence from the pupal stage did not significantly (P < 0.05) differ across treatments and ranged from 98.95 ± 1.82% to 100.00 ± 0.00%. Adult body length resulting from the larvae in each of the treatments was significantly greater than those from the control. Longevity of adults did not differ significantly between treatments. Time from hatching to the development of the first pupa did not differ significantly across treatments; however, development time from hatching to 90% reaching the prepupual stage was significantly different between treatments and ranged from 29.00 ± 1.00 d to 34.33 ± 3.51 d. Development time from hatching to 90% reaching the adult stages was significantly different between treatments. Our results demonstrate that inoculating poultry manure with bacteria from black soldier fly larvae influences the growth and development of conspecific larvae feeding on the manure.