Search Results (95)

Black soldier fly (Hermetia illucens) larvae meal (BSF meal) has emerged as a promising sustainable protein source in aquafeed formulation. This study examined the effects of graded BSF meal inclusion (0%, 20%, 40%, 60%, 80%, and 100% fishmeal replacement) and die head temperature (80 °C, 100 °C, and 120 °C) on the physical properties of extruded diets for Asian seabass (Lates calcarifer), with particular attention to their interactive effects. Both factors significantly affected most pellet quality parameters (p < 0.05), with the exception that no significant interaction effect was observed for moisture content (p = 0.2817). PDI increased progressively with BSF meal inclusion, peaking at 99.14% at 100% substitution and significantly exceeding the control. Higher BSF meal inclusion levels were associated with reduced expansion ratio (ER), bulk density (BD), and sinking velocity (SV). Notably, pellets produced at 80–100% BSF meal inclusion combined with moderate die temperatures (80–100 °C) achieved complete buoyancy (SV = 0.00 m/s). Processing at 80 °C yielded the highest ER and water absorption index (WAI), while 120 °C was associated with elevated water solubility index (WSI), indicating a higher risk of nutrient leaching. These results suggest that BSF meal can replace fishmeal at up to 100% without compromising pellet durability. Extrusion of BSF-based diets at 60–100% inclusion and 80–100 °C is recommended to achieve an optimal balance of structural integrity, hydration properties, and buoyancy for Asian seabass feeds. Full article

This study was designed to assess the protective efficacy of dihydromyricetin (DHM) against intestinal injury in Chinese soft-shelled turtles (Pelodiscus sinensis) caused by partial replacement of fishmeal (FM) with fermented rapeseed meal (FRM), and to uncover the molecular mechanisms involved. Turtles were fed an FM-based control diet, an FRM-substituted diet, or FRM diets supplemented with DHM at 0.5‰ (DHMT1), 1.0‰ (DHMT2) or 2.0‰ (DHMT3) for 8 weeks. Growth performance, digestive enzyme activities, antioxidant parameters, inflammatory cytokines, and intestinal histomorphology were assessed, and intestinal transcriptomics and metabolomics were also performed. FRM replacement significantly improved growth performance; however, this beneficial effect was accompanied by notable intestinal mucosal oxidative damage, as evidenced by decreased villus height, increased lumen space, and lamina propria edema, along with elevated pro-inflammatory cytokines (IL-1β and TNF-α) and MDA content, alongside reduced GSH and CAT activities. DHM supplementation dose-dependently ameliorated these adverse effects by restoring mucosal integrity, digestive enzyme activities, redox homeostasis, and inflammatory balance, ultimately improving growth performance. Transcriptomic KEGG analysis revealed that DHM enriched pathways related to glycerophospholipid metabolism, glutathione metabolism, drug metabolis-cytochrome P450, and polyunsaturated fatty acid metabolism. Metabolomics further confirmed dose-dependent remodeling of phospholipids and bile acids. Integrated omics demonstrated that DHM likely regulates detoxification, anti-inflammatory, membrane repair, and antioxidant pathways. In conclusion, DHM demonstrates a protective effect against FRM-induced intestinal mucosal oxidative damage in P. sinensis, which may be mediated by a synergistic combination of enhanced detoxification, anti-inflammatory modulation, restoration of phospholipid membrane integrity, and reinforcement of antioxidant defenses. Full article

The aquafeed industry is seeking sustainable alternatives to fishmeal, and insect meals are promising candidates. However, quantitative syntheses of their effects on non-fish aquatic animals like shrimp, crabs, turtles, and frogs are limited. This meta-analysis evaluated five insect meals—black soldier fly, Coleoptera, housefly, silkworm, and Orthoptera—on specific growth rate (SGR), weight gain rate (WGR), and feed conversion ratio (FCR). A total of 69 studies (2004–2025) were included. Hedges’ g was pooled using random-effects models, and meta-regressions examined dose–response relationships. Among all categories, only silkworm meal improved or maintained growth, showing no significant negative dose–response relationship. In contrast, black soldier fly and Coleoptera meals impaired growth, with a negative linear dose–response. Subgroup analyses revealed species-specific responses; shrimp, particularly Litopenaeus vannamei, exhibited growth depression, whereas some crab species, including Scylla paramamosain and Eriocheir sinensis, showed tolerance or improved performance. Housefly and Orthoptera meals were evaluated in fewer studies, precluding firm conclusions. Thus, the efficacy of insect meal substitution is jointly determined by insect type and host physiology. Silkworm pupae meal is a favourable fishmeal alternative, while black soldier fly and Coleoptera meals require conservative inclusion limits, especially for shrimp. Full article

The use of insect-based protein sources in aquaculture is gaining increasing attention with Hermetia illucens (black soldier fly, BSF) larvae meal representing a promising substitute to fishmeal (FM). This study evaluated the effect of partial dietary inclusion of BSF meal (BSF0, BSF2.5, BSF5, BSF10%) on the volatilome of rainbow trout (Oncorhynchus mykiss) fillets, before and after cooking, using gas chromatography–mass spectrometry (GC–MS) and a metal oxide sensor-(MOX)-based device. Fish were fed diets with increasing BSF inclusion, and both raw and cooked fillets were analyzed to assess changes in volatile organic compounds (VOCs). GC–MS enabled the identification and semi-quantitative analysis of VOC classes, while MOX sensor responses were processed using Linear Discriminant Analysis (LDA) to assess discrimination among dietary treatments. Results showed that BSF inclusion influenced the volatile profile, with clearer separation at higher inclusion levels (BSF5–BSF10%), especially in cooked fillets. Thermal processing enhanced these differences. GC–MS analysis revealed a reduction in aldehydes and ketones and an increase in carboxylic acids with higher BSF inclusion. Key compounds such as hexanal and heptanal decreased, indicating changes in lipid-derived volatile pathways. Overall, the integration of GC–MS and MOX sensors proved effective in detecting diet-induced changes, supporting their application as effective and reliable tools for quality assessment in aquaculture products, with potential implications for sensory quality that should be further confirmed through dedicated sensory studies. Full article

The goal of this study was to replace the costly fishmeal (FM) with Tenebrio molitor larvae meal (TMLM) in diets for Nile tilapia (Oreochromis niloticus) juveniles. Six isonitrogenous diets were created in order to examine the viability of substituting FM protein with stepwise inclusion levels of TMLM protein, i.e., 0%, 15%, 30%, 45%, 60%, and 75% represented by TMLM0, TMLM15, TMLM30, TMLM45, TMLM60, and TMLM75, respectively. For 90 days, Nile tilapia juvenile (8.8–10.5 g) were fed on TMLM diets three times a day until apparent satiation. Nile tilapia fed on TMLM levels were found to significantly (p < 0.05) boosted their growth and feed efficiency indices by up to 45%, after which their performance declined. In comparison to other treatments, larger villi length/width and increased digestive enzymes activity were observed at this level (TMLM45). At TMLM45, there were no signs of inflammation in the liver tissues but feeding the fish on TMLM60 and TMLM75 showed more vacuolated hepatocytes and fewer hepatic sinusoids. Total protein, albumin, and globulin contents showed significant (p < 0.05) increases in response to TMLM levels in fish feeds; meanwhile no significant (p > 0.05) changes in blood glucose were observed compared to the control one (TMLM0). The values of alanine and aspartate aminotransferase, total cholesterol, and triglycerides decreased significantly (p < 0.05) as TMLM levels increased in fish feeds. In addition, significant (p < 0.05) increases in antioxidant and immunological variables were observed in fish fed with TMLM diets, in particular TMLM45. The current study concluded that the substitution of FM protein by 45% TMLM protein in diets administered to Nile tilapia juveniles significantly improved (p < 0.05) their growth, antioxidant, and immune response compared to the control diet (FM-based diet). Full article

Aquaculture is expanding rapidly, creating a greater need for sustainable and cost-effective feed ingredients to reduce reliance on traditional protein sources such as fishmeal (FM) and soybean meal (SBM). Insect-derived frass, which consists of insect excrement, molted exoskeletons, uneaten substrate, plus associated microbial biomass, has shown potential as a viable and sustainable ingredient in aquafeed. Although traditionally used as an organic fertilizer, its richness in essential nutrients and bioactive compounds highlights its potential as a partial substitute for conventional feedstuffs. This study synthesizes current research on insect-derived frass, focusing on its nutritional composition and effects on growth performance, immunity, health, and gut microbiota in aquaculture species, alongside environmental, economic, safety, and regulatory considerations. Although a wide range of insect species have been evaluated for use in aquafeeds, research on insect frass has primarily focused on black soldier fly and yellow mealworm, with most studies examining its application in omnivorous fish species. Despite its promise as a circular economy-aligned aquafeed ingredient, challenges remain due to nutritional and amino acid variability, largely influenced by the quality of the original insect rearing substrate, as well as species-specific responses and potential contamination risks. To promote widespread adoption of insect-derived frass in aquafeed, there is a need to optimize insect rearing substrate selection and processing, define inclusion levels by insect and target aquatic species, establish safety protocols, and develop harmonized international standards. Full article

A 10-week feeding experiment was conducted to evaluate the effects of replacing fishmeal with cricket meal on the productive performance and transcriptional responses of genes related to nutrient metabolism and growth of blue tilapia (Oreochromis aureus). Five conventional tilapia feeds were formulated to replace fishmeal with cricket meal. Control diet (CD) was formulated with 20% fishmeal, and four diets gradually replaced fishmeal with cricket meal at 20, 40, 60, and 80% (D1–D4). A total of 200 fingerling tilapia (2.00 ± 0.09 g) were randomly distributed into 20 tanks (10 fish/tank), with four replicates per dietary treatment. The results showed that fish fed CD and D1 had higher growth performance values than those fed D2–D4. The feed conversion ratio (FCR) was significantly better in fish fed CD and D1 compared with fish fed D2–D4. The survival rate was similar for all treatments. The transcriptional response of genes related to nutrient digestion, absorption, and transport; lipid metabolism; and the somatotropic axis was marked downregulated in fish fed D2 and D4, whereas in fish fed D3, it exhibited a unique compensatory regulation across most pathways, likely sustained by its higher dietary lipid content. Although cricket meal did not prevent the metabolic effects associated with high soybean meal inclusion, survival remained high across all treatments. Cricket meal can replace up to 20% of the fishmeal in the feed for blue tilapia fingerlings, with soybean meal as the main protein source. Full article

A 10-week growth experiment was conducted to evaluate the physiological effects of dietary phosphorus supplementation on red swamp crayfish (Procambarus clarkii) feeding diets with high Clostridium autoethanogenum protein (CAP) levels. Six isonitrogenous and isolipid diets were formulated: The FM diet contained 10% fishmeal, which is equivalent to a dietary phosphorus level of 1.41%, and the CAP, CAPSP1, CAPSP2, and CAPSP3 diets substituted all fishmeal with CAP and supplemented with 0, 2.5%, 3%, and 3.5% Ca(H₂PO₄)₂, respectively (corresponding to dietary phosphorus levels of 0.66%, 1.27%, 1.40%, and 1.52%). A total of 600 crayfish with an initial mean weight of (5.01 ± 0.02) g were selected and randomly assigned to 15 cages for feeding and sampled at the end of the experiment. Results indicate that high-dose CAP replacing fishmeal caused abnormal hepatopancreatic tissue structure in crayfish, exacerbating lipid deposition and oxidative stress. Compared with the CAP group, the specific growth rate (SGR) of crayfish in the CAPSP2 and CAPSP3 groups significantly increased (p < 0.05). The activities of antioxidant enzymes and lipid-degrading enzymes in the hepatopancreas, along with the relative expression of related genes, were significantly enhanced (p < 0.05). Metabolomic analysis demonstrated significant differences in major differential metabolites and metabolic pathways between the CAP group crayfish and the CAPSP2 group (p < 0.05). CAPSP2 group crayfish exhibited a higher content of phosphatidylcholine (PC) and lysophosphatidylcholine (LPC), with significant enrichment in glycerophospholipid metabolism and fatty acid metabolism pathways (p < 0.05). Overall, supplementing dietary phosphorus levels to 1.40–1.52% effectively mitigated growth retardation, oxidative damage, and lipid metabolism disorders induced by high-proportion CAP replacement of fishmeal. Full article

Three experiments were conducted to evaluate methodologies and determine the digestibility of calcium (Ca) in ingredients of animal origin, using a completely randomized design. In the first experiment, the direct, regression, and substitution methods were compared to determine the true digestibility of calcium in fishmeal (FM). The true ileal digestibility coefficients (TIDCs) obtained were 0.7558 (substitution), 0.6856 (direct), and 0.6130 (regression). Compared with the regression method, the substitution method resulted in greater digestibility. In the second experiment, the TIDCs of three meat and bone meals (MBM) were evaluated by the direct method. The observed values were 0.6212 (MBM1), 0.5393 (MBM2), and 0.8181 (MBM3). The MBM3 resulted in greater digestibility, while there was no significant difference between MBM1 and MBM2. In the third experiment, the TIDC values of the calcium in three poultry byproduct meal (PBM) samples were determined by the direct method, with coefficients of 0.9440 (PBM1), 0.8673 (PBM2), and 0.9127 (PBM3). No significant differences were observed between the evaluated PBM. The substitution and direct methods were effective for FM. The TIDCs of the MBMs ranged from 0.5393 to 0.8181, whereas those of the offal meals ranged from 0.8673 to 0.9440, indicating the importance of considering the differences in calcium digestibility among the ingredients. The direct method is the most efficient and recommended method for estimating true Ca digestibility because of its simplicity and reduced need for analysis and animals. Individually evaluating each source of Ca in broiler feed formulations is essential because of the wide variation in digestibility between them. Full article

In this 8-week feeding trial, we systematically investigated the effects of replacing fishmeal with enzymatically hydrolyzed pork bone meal (EHPBM) at graded inclusion levels (EHPBM0, EHPBM20, EHPBM50, and EHPBM100) in largemouth bass (Micropterus salmoides). The results showed that the EHPBM50 group maintained growth performance comparable to the fishmeal-based control, whereas higher replacement levels led to significant metabolic disturbances. Specifically, the EHPBM100 group exhibited marked reductions in final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR), along with an elevated feed conversion ratio (FCR). Serum biochemical markers—alanine aminotransferase (ALT) and aspartate aminotransferase (AST)—were significantly decreased in a dose-dependent manner under EHPBM50 and EHPBM100 substitution. Regarding whole-body composition, ash content was significantly lower in the EHPBM50 group, while no significant differences were observed in other metrics compared to the control. Furthermore, dietary EHPBM inclusion enhanced systemic antioxidant capacity. All EHPBM substitution groups showed significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, along with significantly reduced malondialdehyde (MDA) levels. In key metabolic pathways, compared with the EHPBM0 group, the expression of mtor and rps6k genes was significantly up-regulated in the EHPBM50 group, while that of g6pase, fbp1, and cpt1 genes was significantly down-regulated. Intestinal integrity markers (occludin, zo-1) and nutrient transporters (pept1, lat1) remained largely unaffected except in the EHPBM100 group, indicating the species’ tolerance to partial fishmeal replacement. In summary, these findings demonstrate that EHPBM can effectively replace up to 50% of fishmeal in largemouth bass feed without compromising growth performance or nutrient utilization, while significantly enhancing antioxidant capacity. Full article

Microalgal protein demonstrates considerable potential for reducing dependence on fishmeal in aquafeeds. However, limited research has been conducted on the effects of Chlorella pyrenoidosa meal (CM) on carnivorous fish species. This study evaluated the impact of replacing 0% to 40% of fishmeal with CM within isonitrogenous and isolipidic diets (designated as CM0, CM5, CM10, CM20, and CM40) on juvenile tiger puffer (initial weight: 11.34 ± 0.01 g) over a 56-day feeding trial. Three replicate tanks were established for each experimental group, with 30 fish per tank. The experimental data were statistically analyzed using one-way analysis of variance (ANOVA) and regression analysis. The results showed that no significant differences were observed in final body weight (FBW: CM0, 55.45 ± 1.87 g; CM40, 45.6 ± 2.09 g) or specific growth rate (SGR: CM0, 2.83 ± 0.06%/d; CM40, 2.48 ± 0.08%/d) among the dietary groups; however, the growth linearly decreased with increasing CM levels. The CM40 group exhibited a significantly higher feed conversion ratio (FCR: CM0, 1.17 ± 0.02; CM40, 1.28 ± 0.03). Muscle texture parameters (hardness, adhesiveness, cohesiveness, springiness, gumminess, and chewiness) and proximate composition were not significantly affected by dietary treatments. In contrast, the CM40 diet significantly decreased the n-3/n-6 polyunsaturated fatty acid (PUFA) ratio in the muscle, while increasing the contents of 18:2n-6 and total n-6 PUFAs. These results indicate that substituting up to 5% of fishmeal with CM did not produce significant adverse effects on growth or body composition, although linear trends indicated a progressive decline in performance at higher inclusion levels. This investigation provides valuable insights into the application of sustainable protein alternatives in feeds for marine carnivorous fish. Full article

This study was conducted in two phases: first, to assess the impact of microbial fermentation on enhancing the nutritional quality of fish by-products, and second, to evaluate the effects of replacing fishmeal with these fermented by-products in the diet of Nile tilapia (Oreochromis niloticus) on growth performance, blood parameters, antioxidant indices, immunity, digestive enzyme activity, and carcass composition. In the initial phase, proteolytic activity of five bacterial strains including Bacillus subtilis (ATCC: 6051), B. licheniformis (IBRCM: 10204), Lactiplantibacillus plantarum (PTCCs: 1058 and 1745), and Lactobacillus casei (PTCC: 1608) was evaluated using growth assays in skimmed milk culture media and analyzed using Image-J software. B. licheniformis exhibited the highest proteolytic activity and was selected for fermentation. Resulting hydrolyzed proteins were characterized by peptides with molecular weights below 11 kDa. In the second phase, fishmeal was replaced with fermented by-products at five levels (0 (control), 25, 50, 75, and 100%). Two hundred ten Nile tilapia with an average weight of 2.83 ± 0.05 g were stocked in fifteen 200 L plastic tanks at three replicates, with 14 fish per tank, and fed daily at a rate of 7% of their body weight for 63 days. With increasing levels of fishmeal replacement (25% to 75%), significant improvements (p < 0.05) were observed in final weight gain, body weight gain, specific growth rate, protein production value, and protein efficiency ratio. Additionally, blood plasma concentrations of hormones T₃ and T₄, immunoglobulin level, the activities of complement (ACH₅₀), and antioxidant enzymes (catalase and superoxide dismutase) increased significantly in fish fed the diets with fermented by-products compared to those of the control diet (p < 0.05). The optimal replacement levels for specific growth rate and feed conversion ratio were identified as 86.28% and 83.91%, respectively. Full article

A limited supply and price shortages of fishmeal with the expansion of aquaculture make it necessary to seek alternative protein sources. Soybean meal (SM) has been the widely preferred replacer for fishmeal in fish diets. Nevertheless, this substitution, especially when given at high doses, potentially shows adverse impact on fish intestinal health. This study aimed to investigate the effect of replacing fishmeal with SM on intestinal health in olive flounder (Paralichthys olivaceus). A 56-day feeding trial was conducted with 450 juvenile fish (initial weight: 6.32 ± 0.01 g) randomly allocated to five diets with graded SM replacement: 0% (FM), 12% (SM12), 24% (SM24), 36% (SM36), and 48% (SM48). The results demonstrated that concentrations of glucose, total triglyceride, and low-density lipoprotein cholesterol increased, whereas total protein and high-density lipoprotein cholesterol contents, and lysozyme activity decreased in serum with increasing dietary SM levels. Meanwhile, total antioxidant capacity and superoxide dismutase activity significantly decreased at replacement levels exceeding 24%, accompanied by elevated malondialdehyde concentration (p < 0.05). Compared with the FM group, the SM24, SM36, and SM48 groups showed significantly reduced VH and increased lamina propria width (p < 0.05). Increasing dietary SM levels upregulated expression of genes related to endoplasmic reticulum stress (ERS) (chop, perk, and grp78), inflammation (tnf-α and il-6), and apoptosis (bax, casp3, casp6, and casp9), while downregulated anti-inflammatory cytokines (il-10 and tgf-β1) and tight junction-related genes (zo-1, zo-2, claudin-5, ocln, muc-13, and muc-15) in the intestine (p < 0.05). There were significant differences in the abundances of intestinal microbiota at both the phylum and genus levels among the FM, SM24, and SM36 groups (p < 0.05), but the clusters and microbiota composition of the SM24 group were more similar to those of the FM group. In conclusion, replacing 24% of fishmeal with SM induced intestinal dysfunction through evoking ERS, inflammation, barrier disruption, and microbial dysbiosis in olive flounder. Full article

The tropical gar (Atractosteus tropicus Gill, 1863) is a prehistoric fish of high nutritional value in southern Mexico and Central America. However, some aspects related to the effects caused by alternative protein sources, such as insect meal, as a substitute for fish meal on the growth and expression of digestive enzyme genes, are still unknown. A total of 225 juveniles of A. tropicus were used and fed five experimental diets, each in triplicate, with different levels of substitution of fishmeal (FM) protein with house cricket meal (HCM) protein. A control diet that contained no HCM (T1-0% HCM) was used, and substitutions ranged from 25 to 100% of FM protein by HCM (T2-25% HCM, T3-50% HCM, T4-75% HCM, and T5-100% HCM) for 45 days. The results of this study indicate that T4-75% HCM showed the best growth indices, such as feed efficiency (EF), feed conversion ratio (FCR), specific growth rate (SGR), as well as higher gene expression of pepsin and trypsin, while chymotrypsin showed higher expression in T3. The higher performance achieved in T4-75% HCM may be due to the fact that, in the early stages, insects are part of the natural diet of A. tropicus. The inclusion of cricket meal as a partial substitute for fish meal is not recommended in quantities greater than T4-75%. Full article

As aquaculture expands, there is a growing demand for sustainable and environmentally friendly feed ingredients that can replace conventional fish meal while maintaining high biological value and digestibility. The use of fishmeal has contributed to overfishing, making it an increasingly limited and unsustainable resource. Tenebrio molitor (TM) is emerging as a sustainable alternative to fishmeal (FM) in aquaculture diets, gaining attention due to its balanced protein composition profile and low environmental footprint. This review critically analyses data from the literature on the use of TM meal as a substitute for fish feed ingredient, focusing on its effects on growth performance, physiological status, and histological changes in the digestive and muscular systems. The influence on the physicochemical and sensory quality of fish meat is also evaluated. The discussion highlights both the benefits and possible adverse effects, such as intestinal inflammation or changes that may occur, depending on the replacement level. The paper presents recommendations and strategies to mitigate these effects, including the use of dietary supplements or partial replacement schemes. Overall, this paper emphasises the promising potential of TM as a sustainable alternative to FM in aquaculture feed, while highlighting the need for further research into the long-term effects, involved metabolic pathways, and standardisation of insect meal production. This review provides valuable insight into the physiological changes that may occur, particularly at high inclusion levels. As TM is utilized in both human nutrition and aquaculture diets, monitoring its physiological effects in fish is essential, since any alterations may have implications for human food safety. Full article