Hermetia Illucens Larvae Research Articles

A new approach to biotransformation and value of kitchen waste oil driven by gut microorganisms in Hermetia illucens

Hermetia illucens larvae are known for their ability to recycle organic waste, but their capacity to recover waste oils and the role of gut microorganisms in this process are not fully understood. To gain further insights, the biological recovery of waste frying oil into valuable lipids and the influence of gut bacteria on this biotransformation were investigated. The larvae efficiently digested and absorbed waste frying oil, demonstrating their potential for converting various oils into insect fat. The presence of different fatty acids in their diet significantly altered gut bacterial communities, enriching certain genera such as Actinomyces, Enterococcus, and Providencia. Redundancy analysis revealed that the composition and structure of these bacterial communities were predictive of their function in the biotransformation of fatty acids and the lipid biosynthesis in the larvae. Specific bacteria, including Corynebacterium_1, Providencia, Actinomyces, Escherichia-Shigella, and others, were identified to play specialized roles in the digestion and absorption of fatty acids, contributing to lipid synthesis and storage. These findings highlight the potential of Hermetia illucens in the biological recovery of waste frying oil and underscore the crucial role of gut microbiota in this process, offering a sustainable approach to waste management and bioenergy production.

Method for Obtaining High-Energy Feed Protein and Fat from Insects

Insects are a valuable and renewable source of feed and food protein and fat. They have an amino acid composition similar to that of fishmeal and meat, and can serve as a worthy replacement for them. The aim of this study was to substantiate the technological parameters of the process of obtaining fat from the Hermetia illucens larvae by a mechanical method on a screw press. A laboratory screw press was used for this research. Before squeezing out the fat, the dried larvae were moistened, crushed and heated in a microwave oven to a temperature of 60 °C. The fat from the larvae was squeezed out in a screw press at different larval moisture levels, screw speeds and cake outlets. The results of this study made it possible to obtain optimal technological parameters for obtaining fat on a screw press: a screw rotation speed of no more than 20 ± 5 rpm; a diameter of the hole for the cake outlet of no more than 7–10 mm; a mass fraction of moisture in the pressed material of 8 ± 2%. The obtained fat fraction was tested for one of the main indicators of fat quality—acid number. It was found that the variable factors do not have a significant effect on the acid number of fat, changing it within the normal range of 10 mg KOH per 1 g of fat, which makes it possible to obtain a good quality product.

Effect of temperature on growth, metabolism, and gas exchange in Hermetia illucens larvae reared under commercial and laboratory conditions

Abstract The world’s socio-economic development is continuously increasing the demand for efficient production of food, feed, and energy from the agricultural sector. In this respect, the emerging production of black soldier fly larvae (BSFL) represents a promising system to upscale low-quality resources to higher-quality resources usable as feed or biodiesel. To optimize BSFL production it is critical to establish methods that are relevant to examine how rearing conditions, including temperature, affect growth, metabolism, and body composition at large scale. In a first set of experiments, we therefore compared how small-scale laboratory respirometry chambers (600 larvae) support gas exchange, growth, and metabolism in BSFL with similar measurements obtained from large-scale commercial conditions (>12 million larvae) at ∼34-35 °C. Having observed that small- and large-scale systems generated comparable measurements of growth and metabolism, we used our small-scale respirometry system to examine in detail how substrate rearing temperature ranging from 27.0 to 41.9 °C influenced growth, metabolism, and body composition in BSFL. Here we found that 7-day growth of BSFL was stable and high at 27, 35, and 39 °C, while a rearing temperature of ∼42 °C caused a severe, but sublethal, depression of growth and metabolism. Despite the general similarities in total growth at 27, 35, and 39 °C, we found considerable acceleration of metabolism and development at the two higher rearing temperatures (35 and 39 °C). In contrast, the lower rearing temperature (27 °C) resulted in reduced CO2 production per kg larvae produced and the was associated with a higher crude protein to crude lipid ratio in larvae after the 7-day growth period. Based on these findings we discuss how continued monitoring of gas exchange in production systems holds a potential to optimize production in the emerging industry of large-scale commercial insect production.

The on growth, histology of intestinal and hepatopancreas of using black soldier fly (Hermetia illucens) larvae meal in the diets of Pontastacus leptodactylus juvenile

ABSTRACT In 60 days of feeding, a trial was conducted to evaluate the effects on liver, gut histology, and growth performance of using defatted black soldier fly Hermetia illucens (BSF) larvae meal as a fish meal (FM) protein alternative in the diet of Pontastacus leptodactylus. Fish meal protein was replaced with BSF meal protein at 0%, 20%, 40%, 60%, 80%, and 100%. Six hundred crayfish with an initial weight of 0.033 g were randomly divided into 24 experimental groups with four repetitions. There were no significant differences observed in cheliped, molting numbers, or survival rates between the groups (p > .05). However, adding more than 60% BSF to feeds caused pathological findings in the hepatopancreas,and the intestines. The results of this study showed that 40% defatted BSF meal can be used as a protein source replacement for fish meal protein without affecting the survival rate and growth of P. leptodactylus juveniles.

The effect of dietary full-fat Hermetia illucens larvae meal on growth performance and intestine physiology in largemouth bass (Micropterus salmoides)

The present study aimed to investigate the effects of different inclusion levels of full-fat Hermetia illucens larvae (HI) meal as a protein source on the growth performance, intestinal morphology, health, and microbiota of largemouth bass. Five isonitrogenous and isolipidic diets were formulated by adding HI to replace 0 % (HI0, control), 10 % (HI10), 20 % (HI20), 30 % (HI30) and 40 % (HI40) of fish meal (FM) in diets. Each diet was randomly assigned to triplicate groups of 30 fish per aquarium. Fish were fed two times daily to apparent satiation for 80 days. The results indicated that weight gain rate, specific growth rate and protein efficiency ratio were not appreciably reduced until more than 30 % of the FM protein was replaced with HI. Fish fed HI40 diet had the lowest fatty acid (C18:3, C20:5, C22:6) contents (P < 0.05). Moreover, the villi height was decreased, villi width and goblet cell number in hindgut was increased in the HI40 group compared with the other groups, respectively. Meanwhile, serum diamine oxidase activity, D-lactate and endotoxin contents increased markedly as the proportion of HI increased (P < 0.05). Notably, the increased dietary HI levels down-regulated the mRNA expression levels of cldnd1b and ocel1 in intestine. Higher malondialdehyde content and down-regulated expression of sod and gpx1a in the intestine were also observed in the HI40 group. Accordingly, the increased dietary HI levels upregulated the expression of intestinal pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and down-regulated anti-inflammatory cytokines (transcriptional growth factor-β1 and interleukin-10) (P < 0.05). In addition, the abundance of both intestinal Lactobacillus and Streptococcus increased significantly, while the abundance of Cetobacterium decreased in the HI20 group (P < 0.05). Broken-line model analysis based on weight gain rate against dietary HI replacement level indicated that the optimum replacement level was 26.79 %. However, including too high proportion of HI could induce intestinal dysbiosis, impair the intestine physical barrier, and finally reduced growth of Micropterus salmoides.

Isolation of chitosan-melanin complex from black soldier fly adults and obtaining nanofibrous materials based on it

The article presents the results of studying the viscosity of chitosan-melanin complex solutions from the larvae of the insect Hermetia illucens and the process of gelation in these solutions in the presence of crosslinking reagents. Chemically cross-linked nanofibers were obtained from solutions of the chitosan-melanin complex in dilute solutions of acetic acid by the method of spinneretless electrospinning. The presence of 14% melanin made it possible to reduce the concentration of acetic acid in the spinning composition.

Black soldier fly larvae efficiently bioconvert the organic fraction of municipal solid waste thanks to the functional plasticity of their midgut

Abstract The saprophagous larvae of Hermetia illucens show promising potential as effective agents for bioconverting organic waste and by-products into valuable biomass. Their capability to efficiently transform organic substrates, varying in nutrient content, origin, texture, and moisture, is strictly correlated with the morphofunctional complexity of their digestive system and the associated microbiota. In addition, post-ingestion mechanisms are set in motion to regulate the midgut activity depending on the feeding substrate, thus ensuring the nutritional requirements of the larvae. This study aims to assess the capability of H. illucens larvae to grow and biotransform the organic fraction of municipal solid waste (OFMSW). In particular, the larvae were reared on substrates mimicking the OFMSW with different nutrient content, and their growth and bioconversion performance, as well as the quality of larval and pupal biomass were evaluated. Our results demonstrate that the nutritional composition of the rearing substrates had minimal impact on the efficiency of the bioconversion process and on the protein, lipid, and chitin content of the insect biomass. This was due to a fine transcriptional regulation of genes encoding enzymes involved in protein, polysaccharide, and lipid digestion in midgut cells. As a consequence, larvae reared on OFMSW with the lowest protein, starch, and lipid content exhibited a significant increase in protease, amylase, and lipase activities. Overall, this study highlights the value of H. illucens larvae in valorising the OFMSW, demonstrating that variations in its composition do not significantly affect the quality of the bioconversion process. These findings hold significant practical implications as current strategies for OFMSW treatment remain unsatisfactory and innovative approaches are needed to enhance bio-waste recycling and reduce the environmental impact of waste management.

Resource Utilization of Residual Organic Sludge Generated from Bioenergy Facilities Using Hermetia illucens Larvae.

Residual organic sludge generated from bioenergy facilities (BF-rOS) is often disposed instead of recycled, thus contributing to further environmental pollution. This study explored the resource utilization of BF-rOS using Hermetia illucens larvae (BSFL). When BF-rOS was fed to BSFL for two weeks, the dry weight per individual BSFL was approximately 15% of that of BSFL that were fed food waste (FW). However, the dry weight increased by approximately two-fold in BSFL that were fed effective microorganism (EM)-supplemented BF-rOS containing 60% moisture. However, under both conditions, the BSFL did not mature into pupae. In contrast, the highest dry weight per BSFL was observed with the BF-rOS/FW (50%:50%) mixture, regardless of EM supplementation. Furthermore, the highest bioconversion rate was observed when the BSFL were fed the BF-rOS/FW (50%:50%) mixture, and the frass produced by the BSFL contained fertilizer-appropriate components. In addition, the nutritional components of the BSFL exhibited a nutrient profile suitable for animal feed, except for those fed BF-rOS only. In conclusion, this investigation demonstrates that BF-rOS should be recycled for fertilizer production by mixing it with FW as a BSFL feed, which generates the valuable insect biomass as potential nutrition for animal feeding.

Effects of Hermetia illucens larvae meal and astaxanthin on intestinal histology and expression of tight junction proteins in weaned piglets.

The weaning phase in piglets causes significant physiological stress, disrupts intestinal integrity and reduces productivity, necessitating strategies to improve intestinal health and nutrient absorption. While current research highlights the role of diet in mitigating these adverse effects, identifying effective dietary supplements remains a challenge. This study evaluated the effects of Hermetia illucens (HI) larvae meal and astaxanthin (AST) on the intestinal histology of weaned piglets. In a controlled experiment, 48 weaned piglets were divided into six groups and received varying levels of HI larval meal (2.5% and 5%) and AST in their diets. The methodology involved comprehensive histological examinations of the small intestine, assessing absorption area, villi elongation, crypt depth, goblet cells, enterocytes and expression of ileal tight junction (TJ) proteins. The study found that HI larval meal significantly improved nutrient absorption in the jejunum and ileum (p < 0.001), thereby enhancing feed conversion. AST supplementation increased the number of enterocytes (p < 0.001). Both HI larval meal and AST positively affected intestinal morphology and function, increasing muscularis muscle mass and villi elongation (p < 0.001 and p < 0.05, respectively). The 2.5% HI meal improved the villi length to crypt depth ratio and slightly increased the goblet cell count (both p < 0.05). Ki-67 antibody analysis showed increased cell proliferation in the duodenal and jejunal crypts, particularly with the 2.5% HI meal (p < 0.001). Insect meal did not affect TJ protein expression, indicating that it had no effect on intestinal permeability. These findings suggest that HI larval meal and AST can enhance the intestinal wellness and productivity of weaned piglets.

Exploring the suitability of Hermetia illucens meal in Clarias magur catfish: effect on growth, physiology and flesh quality

Abstract The effect of substituting Hermetia illucens (HI) meal for fish meal (FM) on the growth performance, survival rate, feed utilization, digestive enzyme activity, immunological function, and flesh quality of Clarias magur (average weight = 3.3 ± 0.05 g) is investigated in this work. Four iso-nitrogenous diets with 35% crude protein were formulated, each with varying levels of HI substitution: HI25%, HI50%, HI75%, and HI100%, then compared to a control diet (HI0%). Following a 90-day experiment, it was observed that the growth performance and feed efficiency were significantly improved at the 50% level (). However, the control group exhibited greater levels of digestive enzymes, specifically protease and lipase activity. The fish’s health status remained unaffected by the substitution of fishmeal, while the 50% HI group showed significant improvements. The high levels of the antioxidant enzymes SOD and CAT, as well as the metabolic product MDA, suggested enhanced antioxidant activity in the groups that received HI inclusion. However, as the substitution level reached 100%, the quality of the flesh decreased, as indicated by increased lipid and adhesiveness, as well as decreased L* and WI (). The findings of the study suggest that HI larvae can replace FM in diet of C. magur. Overall, at 50% level of HI larvae meal inclusion in diet, better growth and immune function was evident, but it does lead to a decrease in flesh quality. This study enhances the existing knowledge on substituting fish meal with insect meal in catfish that are of regional importance. Additionally, it emphasizes the necessity for additional investigation to examine the underlying mechanisms employing biotechnological approaches.

Synergistic impacts of antibiotics and heavy metals on Hermetia illucens: Unveiling dynamics in larval gut bacterial communities and microbial metabolites

Hermetia illucens larvae showcases remarkable bioremediation capabilities for both antibiotics and heavy metal contaminants. However, the distinctions in larval intestinal microbiota arising from the single and combined effects of antibiotics and heavy metals remain poorly elucidated. In this study, we delved into the details of larval intestinal bacterial communities and microbial metabolites when exposed to single and combined contaminants of oxytetracycline (OTC) and hexavalent chromium (Cr(VI)). After conversion, single contaminant-spiked substrate showed 75.5% of OTC degradation and 95.2% of Cr(VI) reductiuon, while combined contaminant-spiked substrate exhibited 71.3% of OTC degradation and 93.4% of Cr(VI) reductiuon. Single and combined effects led to differences in intestinal bacterial communities, mainly reflected in the genera of Enterococcus, Pseudogracilibacillus, Gracilibacillus, Wohlfahrtiimonas, Sporosarcina, Lysinibacillus, and Myroide. Moreover, these effects also induced differences across various categories of microbial metabolites, which categorized into amino acid and its metabolites, benzene and substituted derivatives, carbohydrates and its metabolites, heterocyclic compounds, hormones and hormone-related compounds, nucleotide and its metabolites, and organic acid and its derivatives. In particular, the differences induced OTC was greater than that of Cr(VI), and combined effects increased the complexity of microbial metabolism compared to that of single contaminant. Correlation analysis indicated that the bacterial genera, Preudogracilibacillus, Enterococcus, Sporosarcina, Lysinibacillus, Wohlfahrtiimonas, Ignatzschineria, and Fusobacterium exhibited significant correlation with significant differential metabolites, these might be used as indicators for the resistance and bioremediation of OTC and Cr(VI) contaminants. These findings are conducive to further understanding that the metabolism of intestinal microbiota determines the resistance of Hermetia illucens to antibiotics and heavy metals.

A Multidisciplinary Approach for the Development of a Supply Chain in Biomass Conversion of Agrifood Waste Mediated by Larvae of Hermetia illucens L.: From Rearing to By-Product Exploitation

Black soldier fly larvae (BSFL) can convert various organic substrates into high added-value biomass. In addition, the residue can be used as a soil conditioner. Several studies have been conducted on a laboratory scale that may not represent what happens on a prototype scale. Using fruit and vegetable waste as a basic substrate, mixing them with agro-industry by-products (called co-substrates), the Hermes project set up a process on medium (2 kg) and large (10 kg) scales with two different feeding regimes (1.25 g/BSFL and 2 g/BSFL). At the mature stage, larval biomass was separated from frass (the by-product of the larval rearing). The production of larval proteins and fats and the use of frass as soil conditioning were evaluated. The lowest feeding regime (1.25 g/BSFL) provided the best waste valorization. The shift towards higher production scales is not completely linear. The addition of co-substrates to fruit and vegetable waste, as they are provided by the large-scale retail trade, can help to standardize a process as part of an insect farm. The frass recovered from the residue of rearing (on the diet or on the agrifood leftovers) was composted and used in field to grow a processing tomato variety. The addition of composted frass assured a slightly lower yield than synthetic fertilizer but there was no statistically significant difference (p &gt; 0.10). This suggests that partial replacement of synthetic fertilizer with composted frass has potential. Overall, the work demonstrated that, using a multidisciplinary approach, the interest and the value in building a supply chain based on bioconversion mediated by Hermetia illucens can be emphasized.

The underlying mechanisms of oxytetracycline degradation mediated by gut microbial proteins and metabolites in Hermetia illucens

Hermetia illucens larvae can enhance the degradation of oxytetracycline (OTC) through its biotransformation. However, the underlying mechanisms mediated by gut metabolites and proteins are unclear. To gain further insights, the kinetics of OTC degradation, the functional structures of gut bacterial communities, proteins, and metabolites were investigated. An availability-adjusted first-order model effectively evaluated OTC degradation kinetics, with degradation half-lives of 4.18 and 21.71 days for OTC degradation with and without larval biotransformation, respectively. Dominant bacteria in the larval guts were Enterococcus, Psychrobacter, Providencia, Myroides, Enterobacteriaceae, and Lactobacillales. OTC exposure led to significant differential expression of proteins, with functional classification revealing involvement in digestion, transformation, and adaptability to environmental stress. Upregulated proteins, such as aromatic ring hydroxylase, acted as oxidoreductases modifying the chemical structure of OTC. Unique metabolites, aclarubicin and sancycline identified were possible OTC metabolic intermediates. Correlation analysis revealed significant interdependence between gut bacteria, metabolites, and proteins. These findings reveal a synergistic mechanism involving gut microbial metabolism and enzyme structure that drives the rapid degradation of OTC and facilitates the engineering applications of bioremediation.

Replacing soybean meal with lesser mealworm Alphitobius diaperinus improves broiler productive performances, haematology, intestinal morphology and meat quality

Abstract Insects are becoming more popular as a soybean meal substitute because they can be raised sustainably on food and feed residues, which improves farming efficiency, sustainability, and animal welfare. In the current study, we replaced 4, 8 and 12% SBM with lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae) larvae and determined its effects on productive performances, blood parameters, gut morphometry and meat quality of the broiler chickens. We also compared commercially available black soldier fly Hermetia illucens (Diptera: Stratiomyidae) larvae. A total of 350 one-day-old broiler chicks (Ross 308) were randomly assigned to seven isocaloric and isonitrogenous diets (5 pens/treatment and 10 birds/pen). The results found that 12% A. diaperinus and H. illucens diets significantly () increased the live weight (LW) and average daily weight gain (ADG) while improving feed conversion ratio (FCR) in the broilers. Daily feed intake (DFI) did not show a significant difference () among all the dietary treatments. Haematology and serum biochemistry traits were significantly () improved except MCHC, monocytes, Eosinophils (EO), albumin and creatinine. The 12% A. diaperinus and H. illucens diets showed the highest villus height (Vh) and the lowest crypt depth than other diets. The meat quality traits were statistically () improved except meat pH, drip loss and shear force (). The results of the study highlight the importance of substituting SBM up to 12% with either A. diaperinus or H. illucens larvae, which improves the productive performances, blood parameters, gut morphometry and meat quality of broilers and thus can be incorporated as an alternative protein source in poultry feed.

Biogas Digestate and Sewage Sludge as Suitable Feeds for Black Soldier Fly (Hermetia illucens) Larvae.

Hermetia illucens larvae can use organic wastes as a substrate, which makes them an interesting potential feed. However, waste may contain heavy metals, which are limited in feed. Here, we investigated the ability of H. illucens to grow on organic wastes and measured their heavy metal bioaccumulation. The larvae were fed with food waste, biogas digestates, and sewage sludge. When the first adult fly was visible, the tests were stopped and the larvae immediately processed. The samples (wastes before use, larvae after feeding) were analysed for mineral nutrient and heavy metal content using AAS and ICP-OES, respectively. The results show that the weight of the larvae fed with food waste increased sevenfold, which was broadly in line with expectations. Those fed with sewage sludge and digestate from biogas station increased threefold. While the larvae fed with sewage sludge exceeded the limits for heavy metals, particularly Cd and Pb, in feedstock, those fed with biogas digestate and food waste did not. These findings add to the literature showing the suitability of different wastes as H. illucens feed, and the importance of excluding waste contaminated with heavy metals from larvae intended for use as animal feed, or else diverting these larvae to non-feed uses.

Hermetia illucens larvae fat vs coconut oil to obtain free lauric acid-rich products by chemical or enzymatic hydrolysis

Abstract Lauric acid is present in various vegetable fats and has been shown to be beneficial for human health and well-being. The interest in the properties of this fatty acid has led to an increase in the production and consumption of oils rich in lauric acid, primarily coconut oil. Despite being less known, there is an atypical animal source of lauric acid that can be considered more sustainable and that has levels of this fatty acid comparable to coconut oil, as the case of the larvae of the edible insect black soldier fly (Hermetia illucens) is. Due to the fact that some of the bioactive properties of lauric acid are linked to its free form, and also to facilitate subsequent concentration processes, the release of the fatty acid from the triacylglycerols present in fats becomes necessary. In this study, chemical and enzymatic hydrolysis for transforming both lauric acid-rich fats into a product rich in free fatty acids (FFA) were investigated. Different variables were studied, such as reaction time and the amount of catalyst used, resulting in maximum conversions to FFA in the case of chemical hydrolysis in just 20 min for both fats. Furthermore, the efficiency of the lipase Eversa® Transform 2.0 in generating a lauric acid-rich product from both oils was demonstrated, but in this case, a longer time was needed. The products obtained through both types of hydrolysis contained high percentages of free lauric acid, also exhibiting high stability against oxidation. This makes H. illucens larvae fat a comparable and alternative source to coconut oil to produce lauric-acid rich products useful for different applications.

Apparent total tract digestibility of calcium and phosphorus from partially defatted Hermetia illucens larvae meal in pigs

Abstract Insect meals, which have emerged as a sustainable protein source in animal nutrition, are also rich in calcium and phosphorus and thus might be a valuable source for supplying these minerals in farm animals. The aim of the present study was to determine the apparent total tract digestibility (ATTD) of these minerals from commercially available partially defatted meals of Hermetia illucens (HI) larvae in growing pigs. According to a difference approach, twenty male growing pigs with an average body weight of around 30 kg were divided into five groups of four pigs each and fed either a basal diet or the basal diet blended with one of three HI meals or monocalcium phosphate (MCP, as a positive control) for 14 days. Calcium and phosphorus ATTD were determined, by using the indicator method with acid-insoluble ash as an indigestible marker. Calcium ATTD on average of the three HI meals was 71.2%, ranging from 60.7% to 77.0%, and the ATTD of phosphorus was 80.6%, with a range of 70.8% to 88.9%. Calcium and phosphorus ATTD of MCP were 95.0% and 82.8%, respectively. The study shows that calcium and phosphorus from HI meals exhibit a relatively high ATTD in pigs, similar to that observed from inorganic mineral sources. Thus, HI meal could substantially contribute to the supply of calcium and phosphorus to pigs, thus opening the possibility to conserve scarce minerals resources such as phosphate-rich rocks for pig nutrition.

Characterization of Chitinolitic Bacteria from Hermatia illucent Larvae Waste: Antifungal Activity, Hydrolytic Enzyme, and Phosphate-Potassium Solubilization

Hermetia illucens larvae, also known as the black soldier fly larvae, are best known as the decomposers of organic matter. There are many potential microbes found in the feces of BSF larvae. This research aimed to isolate the chitinolytic bacteria from chicken manure maggot waste, identify the antifugal activity, hydrolytic enzyme activity, phosphate and potassium solubilization, and bacterial species through 16S rRNA gene analysis. The initial screening focused on bacteria with chitinolytic ability. Antifungal activity tests were performed against phytopathogenic fungi, Colletotrichum sp. Isolate MKP02 showed the highest activity in inhibiting the growth of Colletotrichum sp. up to 100% and produced protease and cellulase enzymes, along with the ability to solubilize potassium. Furthermore, the potential isolate MKP04, the isolate shows the highest cellulolytic activity with a percentage of 300%. It can inhibit Colletotrichum sp. fungi, as well as having lipase enzyme content, and being able to dissolve potassium. The results of 16S rRNA gene amplification on the two isolates showed that both isolates were close to bacteria of the genus Lysinibacillus and Brevibacterium. This research is expected to provide valuable information about the bacterial content, levels of hydrolytic enzymes, and the ability to solubilize phosphate and potassium in BSF.

Gamma ray irradiation enhances defatted Hermetia illucens larvae meal as a dietary alternative to fishmeal for Acanthopagrus schlegelii juveniles

The current research investigated whether gamma (γ)-irradiation could improve the viability of defatted Hermetia illucens larvae (HIL) meal as a fishmeal alternative in black sea bream (Acanthopagrus schlegelii) diets. Three diets were formulated with equal protein (420 g/kg) and lipid (80 g/kg) contents. A diet containing 400 g/kg fishmeal was served as the control diet (C), and 50% of fishmeal in diet C was replaced by either defatted HIL meal or γ-irradiated defatted HIL meal to produce diet HR and diet HR10, respectively. Fish fed diet HR exhibited lower final body weight and weight gain compared to those fed diet C, while no statistically significant differences were found between fish fed diets C and HR10. Additionally, fish fed diet HR10 exhibited significantly lower feed intake, feed conversion rate, nitrogen waste, hepatic malondialdehyde content, relative usage of fishmeal and fish oil, fish-in to fish-out ratio, and economic conversion ratio, and meanwhile significantly higher nitrogen retention efficiency, hepatic total antioxidant capacity, economic profitability index and profitability, than those fed diet C. Fish fed different test diets showed statistically equal alpha diversity of intestinal microbiota, whereas the beta diversity of intestinal microbiota in group HR was far from groups C and HR10. Compared to fish fed diet C, the gut microbiota composition of fish fed diet HR showed significant alterations at both the phylum and genus levels. However, the altered composition of intestinal bacteria was partially restored in fish fed diet HR10. The above findings indicate that treating defatted HIL meal with γ-ray can reduce dietary fishmeal content for black sea bream to 200 g/kg without any adverse effects on growth, proximate composition and intestinal microbial diversity, and meanwhile ameliorates the feed utilization, hepatic antioxidant capacity, and intestinal microbiological composition of black sea bream. Furthermore, feeding γ-irradiated defatted HIL meal enhances the economic profitability, while reduces the waste output and reliance on fishery resource of black sea bream aquaculture.

Hermetia illucens Larvae Meal as Partial Fishmeal Replacement in Jade Perch Diet Cultured in Biofloc: Growth Performance, Feed Efficiency and Consumer Acceptance

A 12-week feeding trial on jade perch (Scortum barcoo) was conducted to evaluate the outcomes of partial substitution of fishmeal with black soldier fly larvae meal (BSFLM) in a biofloc system that requires minimal water exchange. The jade perch juveniles were subjected to three dietary treatments namely the 100% fishmeal (FM100), 50% BSFLM (BSF50), and a commercial diet (COM) with 20 individuals per treatment in triplicate tanks. Growth, feed efficiency, and body indices were measured throughout the feeding trial. There were no significant differences observed between the treatments in growth indicators such as the body weight gain (84.55 - 89.10 g), feed conversion ratio (1.77 - 1.87), specific growth rate (1.71 - 1.81 %/day), protein efficiency ratio (1.69 - 1.77), survival rate (90.00 - 98.48 %) and fillet yield (34.94 - 37.08 %). The condition factor is similar in all treatment groups ranging from 1.97 - 2.05. The crude protein and moisture content making up fish body composition are not statistically different among treatments, but higher crude lipids are obtained in the BSF50 (32.33 ± 5.27 g/kg) and COM (31.67 ± 2.76 g/kg). Higher hepatosomatic index (HSI) and visceral fat somatic index (VFSI) values were observed in BSF50 group at 3.13 ± 0.25 and 10.89 ± 1.68, respectively. Furthermore, sensory evaluation comparing the consumers' evaluation and acceptance of the fish cultured with the different dietary treatment and culture system shows that the group fed BSF50 and cultured in biofloc system received similar overall appreciation with the FM100 and COM group. In conclusion, BSFLM inclusion in the jade perch diet, combined with the biofloc system, is feasible to be explored further.