Hermetia Illucens Meal Research Articles

New Eco-Sustainable Feed in Aquaculture: Influence of Insect-Based Diets on the Content of Potentially Toxic Elements in the Experimental Model Zebrafish (Danio rerio).

According to the concept of circular economy, insects represent good candidates as aquafeed ingredients. Nevertheless, there are some potential chemical risks linked with insect consumption. In this study, we reared the teleost Danio rerio, used as an experimental model, with five experimental diets characterized by increasing levels (0%, 25%, 50%, 75%, and 100%) of full-fat Hermetia illucens (Hi) prepupae, substituting for fish meal (FM) and fish oil (FO). We investigated the presence of potentially toxic elements (PTEs) Cd, Pb, Ni, As, and Hg in larval (20 days), juvenile (2 months), and adult (6 months) fish. Quantitative determinations of Cd, Pb, Ni, and As were made with an atomic absorption spectrometer; the total mercury content was determined by a direct mercury analyzer. The substitution of FM and FO with Hermetia illucens meal led to a reduction in the content of some PTEs, such as Pb, As, and Ni, in fishfeed, leading to concentrations below the legal limit of undesirable substances in animal feed. By increasing the Hi meal dietary content, we observed in the Danio rerio specimens an increase in Cd, Pb, and Ni content and a reduction in As content for all life stages. Moreover, a general increase in the content of Cd, Pb, Hg, and Ni from larvae to juvenile was measured, while the shift of Danio rerio from the juvenile to the adult stage involved a significant increase in the content of Pb, Hg, and Ni. Larvae had a reduced ability to bioaccumulate metal(loid)s compared to juveniles and adults. In conclusion, the content of PTEs in Danio rerio is influenced both by the type of diet administered and by the life stage of the animal itself. This research demonstrates the possibility of using Hi prepupae as an aquafeed ingredient without exposing fish to a chemical risk and, in perspective, allows applying these eco-sustainable diets for the breeding of edible fish species, without endangering human health.

Fishmeal Replacement with Hermetia illucens Meal in Aquafeeds: Effects on Zebrafish Growth Performances, Intestinal Morphometry, and Enzymology

Fishmeal (FM) is still the most important protein source in aquafeeds. However, due to the reduction of wild fish stocks used for FM production, its manufacturing it is now unsustainable. Insect meal represents a valid alternative to FM, due to the low carbon footprint of its production and its high nutritional value. The aim of this study was to investigate the potentials of replacing FM with black soldier fly (Hermetia illucens) meal (HIM) in aquafeeds, using zebrafish as the animal model. Four diets were formulated with increasing HIM/FM replacement rate (the control diet contained 20% FM). Mortality rates, growth performances, and feed consumptions were measured, and fish intestine samples were collected for histological and enzymatic analysis. After 49 days, all groups almost tripled their initial body weight (cumulative body weight gain ranged between 143.9 and 155.2 mg), and no statistically significant differences among treatments were observed in relation to growth performances and histological traits. Contrarily, trypsin, alkaline phosphatases, and alpha amylase–glucoamylase activities were significantly reduced when the FM replacement rate was increased. In conclusion, HIM may represent an alternative to FM, since no adverse effects were observed when it was included up to 20% in the zebrafish diet, even when replacing 100% of the FM.

Performance and fillet traits of rainbow trout (Oncorhynchus mykiss) fed different levels of Hermetia illucens meal in a low-tech aquaponic system

In this study, we evaluated the effects of dietary substitution of fishmeal (FM) with partially defatted Hermetia illucens meal (HI) on the growth, feed digestibility, gut morphology, and fillet quality of rainbow trout reared in a low-tech aquaponic system. A total of 173 rainbow trout (initial body weight: 156 g ± 39.8 g) were distributed among nine experimental aquaponic units. Three diets were fed to fish (three aquaponic units per dietary treatment) over a period of 76 days, i.e. H0 diet (control), H6 diet, and H12 diet containing 0 g/kg, 62 g/kg, or 124 g/kg of HI and 200 g/kg, 150 g/kg, or 100 g/kg of FM, respectively. We found that the apparent digestibility coefficients of diets were unaffected by the inclusion level of dietary HI. At the end of the trial, trout mortality was low (2.9%) and unaffected by dietary treatment. The specific growth rate was, however, lower in fish fed the H12 diet than in those fed H0 and H6 diets after 26 days (1.07% d−1 vs. 1.22% d−1; P < 0.001) and at the end of the trial (0.81% d−1 vs. 0.88% d−1; P < 0.05). In contrast, dietary inclusion of HI appeared to have no appreciable effect on the feed conversion ratio (on average 1.53), final weight (303 g), fish condition factor (1.40), viscerosomatic index (10.9%), or hepatosomatic index (1.22%). The inclusion of HI was, nevertheless, found to promote a 10% increase in the density of goblet cells in the gut of fish fed the H12 diet compared with those receiving the H0 diet (P < 0.05). With regards to fillet traits, redness and yellowness indices were lower in fish fed the H12 diet than in those fed the H0 diet. Although dietary HI had little effect on the proximate composition and fatty acid profile of fish, the proportions of C12:0 and C14:0 increased with HI dietary inclusion. In conclusion, fish growth and fillet quality were essentially unaffected by a 25% fish meal replacement with HI in isonitrogenous and isoenergetic diets (control diet containing 200 g/kg of fish meal), whereas at a replacement rate of 50%, we detected certain effects on gut histology and fillet colour and nutritional characteristics, which warrant further investigation.

Evaluation of the fat oxidation quality of commercialHermetia illucens meal

Hermetia illucens meal is one of the most promising alternatives to fishmeal and soymeal. Fat oxidation quality of these products is crucial, as it directly influences the palatability of feed, and health of animals consuming it. During this study, oxidative quality of commercialH. illucens meal, fishmeal and soymeal was evaluated by measuring fatty acid profile, free fatty acid content, peroxide value,p-anisidine value and electron spin resonance spectra of lipid free radicals. Fishmeal and soymeal used in this study had antioxidants, either added (in fishmeal), or naturally present (in soymeal), whereasH. illucens meal had no added antioxidants. Results indicate that fishmeal contain high levels of lipid free radicals and secondary oxidation products, which may adversely affect the health of the animal consuming it. In contrast,H. illucens meal and soymeal are stable in terms of oxidative quality. The majority of soymeal consumed in Europe originates from South America, where soy farming is linked to several social and environmental challenges.H. illucens meal could be a local and sustainable alternative to fishmeal and soymeal. Oxidative stability ofH. illucens meal could be attributed to the short supply chain and careful design of the thermal processing step. In case ofH. illucens meal, thermal processing is effective enough to deactivate sn-1,3-lipase, while causing minimal damage to unsaturated triglycerides.H. illucens meal contain high levels of saturated fats and is thermally processed at mild conditions in comparison to fishmeal and soymeal. This may offer advantage toH. illucens meal in terms of fat oxidation quality.

Black Soldier Fly Larvae Meal as Alternative to Fish Meal for Aquaculture Feed

Hermetia illucens meal (HIM) as ingredient in feed represents a way to achieve more sustainable food production. The aim was to characterize the chemical, microbiological and organoleptic characteristics of four diets for Sparus aurata, isoenergetic and isoproteic, containing 0%, 25%, 35% and 50% of HIM in substitution of fish meal (FM). Analyses were carried out using gas chromatography for fatty acids and amino acids, ICP-OES for minerals and liquid chromatography for aflatoxins and following International Organization for Standardization methods for microbial flora. E-sensing analysis of the diets was evaluated using an artificial sensory platform (E-eye, E-nose and E-tongue). The chemical results were submitted to a one-way ANOVA while Principal Component Analysis (PCA) of the e-sensing data was performed. No significant differences were observed for polyunsaturated fatty acids, thrombogenic and peroxidation indices among the diets. The replacement of FM with HIM increased the content of lysine, methionine, isoleucine, leucine, threonine and valine, while phosphorus, calcium and sodium content decreased (p &lt; 0.01) as the percentage of HIM increased. Lead was significantly below the maximum level set by the EU regulation. The diets showed good hygienic and sanitary quality. The artificial senses permitted distinguishing color, odor and taste among the diets. Data allow considering Hermetia illucens as alternative protein source in fish nutrition.

Hermetia illucens and Poultry by-Product Meals as Alternatives to Plant Protein Sources in Gilthead Seabream (Sparus aurata) Diet: A Multidisciplinary Study on Fish Gut Status.

Simple SummarySustainability and fish welfare have been receiving increasing attention in the aquaculture sector, with an emphasis on the search for new, sustainable, and healthy aquafeed ingredients. For many years, plant ingredients have been widely used in aquafeed formulation; however, negative side effects on gut welfare have often been reported in several carnivorous fish species. From this perspective, alternative ingredients such as poultry by-products and insect meal are receiving attention due to their low ecological footprint and high nutritional value. In the present study, these two ingredients were used, singly or in combination, to formulate practical diets for gilthead seabream (Sparus aurata). After a twelve-week feeding trial, a multidisciplinary laboratory approach including histological, molecular, and spectroscopic techniques was adopted in order to investigate fish physiological responses to the new test diets. The results obtained showed excellent zootechnical performances and ameliorated gut health in fish fed dietary inclusions of poultry by-products and insect meal compared to those fed a vegetable-based diet. In addition, the modulation of nutrient absorption in relation to the ingredients used was highlighted by means of spectroscopic tools. The results obtained demonstrated that poultry by-products and insect meal can be successfully used to replace plant-derived ingredients in diets for gilthead seabream without negatively affecting fish welfare.The attempt to replace marine-derived ingredients for aquafeed formulation with plant-derived ones has met some limitations due to their negative side effects on many fish species. In this context, finding new, sustainable ingredients able to promote fish welfare is currently under exploration. In the present study, poultry by-products and Hermetia illucens meal were used to replace the vegetable protein fraction in diets totally deprived of fish meal intended for gilthead seabream (Sparus aurata). After a 12-week feeding trial, a multidisciplinary approach including histological, molecular, and spectroscopic techniques was adopted to investigate intestine and liver responses to the different dietary formulations. Regardless of the alternative ingredient used, the reduction in dietary vegetable proteins resulted in a lower incidence of intestine histological alterations and inflammatory responses. In addition, the dietary inclusion of insect meal positively affected the reduction in the molecular inflammatory markers analyzed. Spectroscopic analyses showed that poultry by-product meal improved lipid absorption in the intestine, while insect meal induced increased liver lipid deposition in fish. The results obtained demonstrated that both poultry by-products and H. illucens meal can successfully be used to replace plant-derived ingredients in diets for gilthead seabream, promoting healthy aquaculture.

Antioxidant Status and Liver Function of Young Turkeys Receiving a Diet with Full-Fat Insect Meal from Hermetia illucens.

Simple SummaryInsects can be used as an alternative source of protein and fat in poultry feed. To date, in most research, the administration of invertebrates as a replacement for soybean meal in chicken diets has produced satisfactory results. We hypothesized that full-fat insect meal from Hermetia illucens (HI) larvae can also be an acceptable source of protein and energy in the diet of young turkeys, and at the same time can improve their antioxidant status and metabolism. Our research showed that the level of HI meal in the diet of turkeys should not exceed 5%. The use of a higher level of HI than 5% in the diet of young turkeys has a negative effect on lipid metabolism, lipid oxidation and fat deposition in the liver.We hypothesized that full-fat insect meal from Hermetia illucens (HI) larvae can be an acceptable source of protein and energy in the diet of young turkeys, in an amount adapted to the nutritional needs of these birds, and at the same time can improve their antioxidant status and metabolism. The turkeys were fed a control diet (HI0) without the insect meal, and three diets with increasing HI content of 5%, 10% and 15% (treatments HI5, HI10 and HI15, respectively). The use of 10% or 15% HI in the diet of young turkeys, while beneficially raising levels of P, Fe and Hb, has a negative effect on lipid metabolism, increasing TC levels, lipid oxidation, and fat deposition in the liver. The inclusion of 5% HI in the diet of young turkeys has no adverse effect on the lipid status and histology of the liver, but it does not improve antioxidant status. To conclude, the level of HI meal in the diet of turkeys should not exceed 5%. However, as similar studies on turkeys have not yet been published, overly general conclusions should not be drawn from the results of the present study, and further research is necessary.

Effects of dietary Hermetia illucens meal inclusion on cecal microbiota and small intestinal mucin dynamics and infiltration with immune cells of weaned piglets

BackgroundThe constant interaction between diet and intestinal barrier has a crucial role in determining gut health in pigs. Hermetia illucens (HI) meal (that represents a promising, alternative feed ingredient for production animals) has recently been demonstrated to influence colonic microbiota, bacterial metabolite profile and mucosal immune status of pigs, but no data about modulation of gut mucin dynamics are currently available. The present study evaluated the effects of dietary HI meal inclusion on the small intestinal mucin composition of piglets, as well as providing insights into the cecal microbiota and the mucosal infiltration with immune cells.ResultsA total of 48 weaned piglets were randomly allotted to 3 dietary treatments (control diet [C] and 5% or 10% HI meal inclusion [HI5 and HI10], with 4 replicate boxes/treatment and 4 animals/box) and slaughtered after 61 days of trial (3 animals/box, 12 piglets/diet). The cecal microbiota assessment by 16S rRNA amplicon based sequencing showed higher beta diversity in the piglets fed the HI-based diets than the C (P < 0.001). Furthermore, the HI-fed animals showed increased abundance of Blautia, Chlamydia, Coprococcus, Eubacterium, Prevotella, Roseburia, unclassified members of Ruminococcaceae, Ruminococcus and Staphylococcus when compared to the C group (FDR < 0.05). The gut of the piglets fed the HI-based diets showed greater neutral mucin percentage than the C (P < 0.05), with the intestinal neutral mucins of the HI-fed animals being also higher than the sialomucins and the sulfomucins found in the gut of the C group (P < 0.05). Furthermore, the piglets fed the HI-based diets displayed lower histological scores in the jejunum than the other gut segments (ileum [HI5] or ileum and duodenum [HI10], P < 0.05).ConclusionsDietary HI meal utilization positively influenced the cecal microbiota and the small intestinal mucin dynamics of the piglets in terms of selection of potentially beneficial bacteria and preservation of mature mucin secretory architecture, without determining the development of gut inflammation. These findings further confirm the suitability of including insect meal in swine diets.

Effects of Partially Defatted Hermetia illucens Meal in Rainbow Trout Diet on Hepatic Methionine Metabolism.

Simple SummaryFor sustainable aquaculture development, fish meal from the sea in aquafeed should be replaced with other sustainable materials such as insect larvae. The authors fed black soldier fly maggot meal to rainbow trout and examined the expression of three genes and two metabolites involved in turn-over of methionine that is an essential amino acid in fish. According to the increase in the maggot content in the aquafeed, gene expression was modulated to maintain an optimal level of methionine metabolites. Dietary replacement of up to 50% of fish meal with the maggot meal was acceptable, implying future development of a new aquafeed for sustainable aquaculture.This study investigated, for the first time, the effects of replacement of fishmeal (FM) with insect meal from Hermetia illucens (HI) on the transcript levels of three genes involved in methionine (Met) metabolism in rainbow trout (Oncorhynchus mykiss) liver. Two target genes—betaine-homocysteine S-methyltransferase (BHMT) and S-adenosylhomocysteine hydrolase (SAHH)—are involved in Met resynthesis and the third one—cystathionine β synthase (CBS)—is involved in net Met loss (taurine synthesis). We also investigated the levels of two Met metabolites involved in the maintenance of methyl groups and homocysteine homeostasis in the hepatic tissue: S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). Three diets were formulated, an FM-based diet (HI0) and two diets in which 25% (HI25) and 50% (HI50) of FM was replaced with HI larvae meal. A 78-day feeding trial involved 360 rainbow trout with 178.9 ± 9.81 g initial average weight. Dietary replacement of up to 50% of FM with HI larvae meal, without any Met supplementation, did not negatively affect rainbow trout growth parameters and hepatic Met metabolism. In particular, Met availability from the insect-based diets directly modulated the transcript levels of two out of three target genes (CBS, SAHH) to maintain an optimal level of one-carbon metabolic substrates, i.e., the SAM:SAH ratio in the hepatic tissue.

An OLED-based genosensor for the detection of Hermetia illucens in feeds

Recently, the insects meal has been released by the European Union as an ingredient in aquafeeds and only seven insect species have been allowed to be used for these preparations. To avoid misleading results, a suitable method for the detection of these insect species in food/feed, would be highly desirable. In this paper, we present an innovative, sensitive, specific and low-cost Point-of-Care apparatus, based on DNA probes for the detection of one of the most popular insects used in aquafeed preparation, Hermetia illucens (HI), commonly known as black soldier fly. The DNA probes adopted for this genosensor have been designed to enable a very specific insect recognition which were derived from DNA primers. The DNA primers were first tested with qPCR. Forty different samples (animal species and common aquafeed ingredients) have been tested to check the possible cross-reactivity, confirming the adequate primers specificity. The primers have been used in a practical application, like the detection of HI in complex matrices of practical aquafeeds. The DNA probes derived by these primers have been then applied to implement an Organic Light Emitting Diode (OLED) based genosensor. The developed genosensor has been tested with HI DNA directly extracted from the insect, without any DNA amplification; a good test sensitivity has been obtained, being 0.75 ng/μl its detection (LOD) limit. Then, the genosensor has been tested with the DNA extracted from the same aquafeeds used in the qPCR experiments. The results obtained by these two methods have then been compared giving very good consistency and both allowed to detect HI meal up to a minimum threshold of 5 g/100gr feed.

Black soldier fly and gut health in broiler chickens: insights into the relationship between cecal microbiota and intestinal mucin composition

BackgroundThe relationship between diet and intestinal microbiota and mucin composition appears to be fundamental for poultry gut health. The effects of insect meal (whose role as alternative feed ingredient is now well recognized) on gut microbiota and mucin composition have recently been reported in Tenebrio molitor-fed free-range and broiler chickens, but no data are currently available for Hermetia illucens (HI)-fed broilers. The present study evaluated the effects of dietary HI meal inclusion on cecal microbiota and intestinal mucin composition of broiler chickens.ResultsA total of 256 male broiler chickens were allotted to 4 dietary treatments (control diet [C] and 5%, 10% and 15% HI meal inclusion, with 8 replicate pens/treatment and 8 birds/pen) and slaughtered at 35 d of age (2 animals/pen, 16 birds/diet). The cecal microbiota assessment by 16S rRNA amplicon based sequencing showed lower alpha diversity in HI15 chickens (Shannon, P < 0.05) and higher beta diversity (Adonis and ANOSIM, P < 0.001) in birds fed HI diets than C. Furthermore, HI15 birds displayed significant increase of the relative abundance of Proteobacteria phylum (False Discovery Rate [FDR] < 0.05) when compared to HI10. L-Ruminococcus (Ruminococcus from Lachnospiraceae family), Faecalibacterium, Blautia and Clostridium genera were found to be characteristic of HI5 cecal microbiota (FDR < 0.05), while broiler chickens fed HI10 and HI15 diets were characterized (FDR < 0.05) by Lactobacillus and Ruminococcus (HI10) and Bacteroides, Roseburia and Helicobacter genera (HI15). Periodic-acid Schiff, Alcian Blue pH 2.5 and high iron diamine staining on small and large intestine also demonstrated lower mucin staining intensity in the intestinal villi of HI10 and HI15 birds than C (P < 0.05).ConclusionsDietary HI meal utilization at low inclusion levels (i.e., 5%) positively influenced either the cecal microbiota or the gut mucin dynamics in terms of selection of potentially beneficial bacteria and increase in villi mucins. However, high inclusion levels (in particular the 15%) may have a negative influence in terms of partial reduction of microbial complexity, reduction of potentially beneficial bacteria, selection of bacteria with mucolytic activity and decrease in villi mucins.

Can the inclusion of black soldier fly (Hermetia illucens) in diet affect the flesh quality/nutritional traits of rainbow trout (Oncorhynchus mykiss) after freezing and cooking?

Physical and chemical parameters of rainbow trout fillets were tested during 120 days of frozen storage and following cooking. The fillets were obtained from rainbow trout-fed diets where dietary fishmeal was substituted with Hermetia illucens meal at 0, 25 and 50% inclusion levels, corresponding to control (C), Hi25, and Hi50 diets. Variations in quality traits of fillets emerged after 30 days of frozen storage, however they remained almost unchanged for the other 90 days. Increasing levels of H. illucens did not affect pH, shear stress, colour and water holding capacity of fillets. Saturated fatty acids were highly present in Hi50 samples, the polyunsaturated and some monounsaturated ones were higher in C than Hi50, whereas Hi25 always assumed intermediate contents in raw and cooked samples. A medium substitution at the 25% seemed to be the most practical application of insect meal in order to not modify too much the fillets characteristics.

Influence of Hermetia illucens meal dietary inclusion on the histological traits, gut mucin composition and the oxidative stress biomarkers in rainbow trout (Oncorhynchus mykiss)

Insect protein meals are considered as a promising alternative feedstuff in aquafeeds, but until now the effects induced by its dietary inclusion on histological features, gut mucin composition and oxidative stress in fish are still not assessed. In the present study, we describe these effects after inclusion of a partially defatted Hermetia illucens (HI) larvae meal in Oncorhynchus mykiss diets. Three isoproteic, isolipidic and isoenergetics diets were formulated containing HI larvae meal in partial substitution of fish meal: 0% (HI0, control diet), 25% (HI25) and 50% (HI50), corresponding to dietary inclusion levels of 0, 20% and 40% of HI. Fish were fed for 78 days with the experimental diets and at the end of the growing trial, histological and histochemical evaluations were performed on spleen, liver and gut samples of control and treatment groups. Oxidative stress biomarkers, such as superoxide dismutase, catalase, glutathione peroxidases, ethoxyresorufin O-deethylase, glutathione S-transferase, glutathione reductase, total glutathione and malondialdehyde were investigated in liver and kidney of experimental groups.Histopathological examination of liver, spleen and gut revealed no adverse effects following increasing levels of insect meal inclusions. Hermetia illucens consumption stimulated higher production of neutral than acidic mucins. Altered values of several antioxidant biomarkers indicated an unbalance of oxidative homeostasis in liver and mainly in kidney, linked to the feeding conditions. While lowering of glutathione peroxidase activity may reflect slight adverse effect of HI meals in both tissues, strengthening in levels of ethoxyresorufin O-deethylase, glutathione S-transferase and total glutathione may indicate the shielding of HI meals-mediated oxidative process. Although the administration of both inclusion levels of insect meal did not negatively affect the histological features in fish, the changes of oxidative stress biomarkers advise for an HI dietary inclusion lower than 20%.

Hermetia illucens meal as fish meal replacement for rainbow trout on farm

In a 7-week on-farm feeding trial rainbow trout (Oncorhynchus mykiss) were provided with a diet containing 28% mechanically de-fatted insect meal prepared from larvae of the black soldier fly, Hermetia illucens (HIM) and compared to a control that received a certified organic and fishmeal based diet. In the test diet insect meal replaced almost 50% of the fishmeal. The whole experiment was conducted under practical conditions on an organically certified rainbow trout farm in Switzerland. Fish of initially 66.5±2.3 g body weight were grown to 125±4.5 g and assessed for their growth performance, as well as analysed for their proximate composition, feed conversion ratio, fatty acid contents and organoleptic properties. Improved lipid utilisation and decreased protein utilisation were observed in fish fed the HIM diet. Furthermore, in a controlled degustation no differences except a slightly darker coloration of fish fed HIM were observed. The experiment demonstrated that substantial replacement of fishmeal by insect meal is possible without compromising growth, feed conversion and product quality. However, the decreased protein utilisation efficiency in HIM fed fish might lower production efficiency when applied over a whole production cycle and not only over 7 weeks.

Nutritional value of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens: Apparent nutrient digestibility, apparent ileal amino acid digestibility and apparent metabolizable energy

The aim of this study was to determine the apparent digestibility coefficients of the total tract (CTTAD) of nutrients and the apparent metabolizable energy (AME and AMEn) of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens. The amino acid (AA) apparent ileal digestibility coefficients (AIDC) was also determined. The experimental diets were: a basal diet and two diets prepared by substituting 250g/kg (w/w) of the basal diet with Tenebrio molitor meal (TM) or Hermetia illucens meal (HI). No statistical difference was found between the two insect larval meals for the CTTAD of the nutrients, except for the CTTAD for ether extract (P<0.001) where the HI meal proved to be more digestible than the TM meal (0.99 and 0.88, respectively). The CTTAD for DM was 0.60 and 0.53; 0.66 and 0.66 for OM; 0.60 and 0.51 for CP, whereas it was 0.64 and 0.69 for GE, for TM and HI, respectively. No difference was observed between TM and HI (P>0.05) for AME or AMEn (AME=16.86 and 17.38MJ/kg DM, respectively; AMEn=16.02 and 16.60MJ/kg DM, respectively). The average AIDC of the 17 analyzed AAs was higher (P<0.001) in TM than in HI (0.86 and 0.68, respectively) because the AIDC of isoluecine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glycine, glutamic acid and tyrosine was higher (P<0.05) in TM than in HI. Overall, the present results have shown that TM and HI meals are excellent sources of AME for broilers and a valuable source of digestible AA, particularly as far as TM meal is concerned.