Search Results (90)

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

This study focused on the effects of including a mixture of Hermetia illucens (HI) and Tenebrio molitor (TM) meals on feed colour, growth performance, carcass yield, somatic indexes, nutrient digestibility, intestinal microbiota, histomorphometry, and fillet quality of rainbow trout (Oncorhynchus mykiss). Seven diets were formulated: one control diet (CTRL) containing 15% fishmeal, two diets where the fishmeal was replaced with 100% HI (HI100) or TM (TM100) meal, and four diets containing increasing levels of a mix (1:1) of HI and TM meals, replacing 25% (MIX25), 50% (MIX50), 75% (MIX75) and 100% (MIX100) of the fishmeal. A total of 378 fish (average weight: 126 ± 1.71 g (g)) were randomly distributed in 21 experimental tanks (3 replicates/treatment and 18 fish/replicate) and fed for 84 days. A digestibility trial was also conducted to assess the apparent nutrient digestibility coefficients of the diets. Diet significantly affected pellet colour (L*, a*, b*; p < 0.001), with CTRL and MIX25 being the lightest and HI100 and MIX75 the darkest. Fillet colour, pH_24h, and drip loss were significantly affected by diet (p < 0.001). The pH_24h parameter, reflecting stress and freshness, was lowest in MIX25 and highest in MIX75, suggesting a synergistic effect and potential impact on shelf life. No significant differences were found in growth performance, carcass yield, somatic indexes, fillet chemical composition, intestinal microbiota, and the histopathology of internal organs among the experimental diets (p > 0.05), nor in nutrient digestibility. This study confirms that HI and TM meals, alone or combined, are viable alternatives in low-fishmeal diets for rainbow trout. Full article

The environmental burden of widely used protein sources in animal feeds, such as soybean and fishmeal, has raised concerns about the sustainability of current livestock production systems. In response, alternative protein sources are being explored, with insect meal emerging as a promising candidate. This study conducted a comparative Life Cycle Assessment (LCA) of four compound pig feed formulations differing in protein composition, incorporating soybean meal, fishmeal, and Tenebrio molitor (insect) meal. The LCA followed ISO 14040/44 standards and applied both mass-based and protein-based functional units (FUs) to examine how FU choice influences environmental outcomes. Results showed that crop-derived ingredients, particularly soybean meal, drove most environmental burdens due to land use change and fertilizer inputs. Replacing soybean with insect meal led to impact reductions in key environmental categories. Insect meal’s scalability, efficient land use, and potential waste valorisation supported its role as a sustainable alternative. The study also highlighted key sustainability issues not assessed by LCA, such as overfishing and ecosystem disruption, associated with fishmeal. Overall, insect meal appeared to be a strong replacement for soybean and fishmeal, with soy substitution proving key to reducing environmental burdens. Finally, the protein-based FU was more relevant given the study’s nutritional focus. Full article

Background: Aquaculture increasingly seeks sustainable alternatives to fishmeal, a key protein source in fish diets. Black Soldier Fly Larvae (BSFL) meal is a promising substitute, but its effects on fish growth, immunity, and gut health need further investigation. This study aimed to evaluate the impact of varying BSFL inclusion levels on juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂), a widely farmed species in tropical aquaculture. Methods: Juvenile hybrid grouper were fed diets with four levels of BSFL substitution (0%, 10%, 30%, and 50%) over 56 days. Key metrics such as growth performance, immune function, antioxidant capacity, and gut transcriptome were analyzed. Results: Replacing fish meal with BSFL meal had no significant effect on the survival rate of hybrid grouper (p > 0.05) but significantly affected growth performance, immune function, and antioxidant capacity (p < 0.05). BSFL10 and BSFL30 groups showed good growth and elevated immune enzyme activity, with significantly higher HIS levels (p < 0.05); the Wf of the BSFL10 group was comparable to the control. However, excessive replacement (BSFL50) led to reduced growth (Wf significantly lower, p < 0.05) and increased oxidative stress, as indicated by higher CAT activity (p < 0.05). Transcriptomic analysis revealed upregulation of immune- and metabolism-related genes with increasing BSFL levels, with immune pathways notably activated in the BSFL50 group. Conclusions: BSFL meal is a promising alternative to fishmeal in juvenile hybrid grouper diets, with moderate inclusion (10–30%) being most beneficial. Excessive BSFL substitution (50%) may impair fish health, highlighting the need for careful formulation in aquaculture diets. Full article

As the global demand for aquafeed ingredients continues to rise, sourcing sustainable alternatives is crucial for aquaculture industries. This study aimed to explore the potential of enzymatic hydrolysate as a substitute for traditional fishmeal and soybean meal in diets for juvenile sea cucumbers (Apostichopus japonicus). Three isonitrogenous (15% crude protein) and isolipidic (2.4% crude lipid) diets were formulated: a control diet containing 10% fishmeal and 5% soybean meal and two experimental low-fishmeal (8%) and low-soybean meal (0%) diets, supplemented with either 8% enzymatically hydrolyzed fish stickwater (EFS) or 8% enzymatically hydrolyzed chicken pulp (ECP), designated as Control, EFS, and ECP, respectively. Juvenile sea cucumbers (initial body weight, 0.25 ± 0.01 g) were fed these diets for 84 days to evaluate the effects of ECP and EFS on their growth performance, antioxidant capacity, and inflammatory responses. The results revealed significantly higher final weights and specific growth rates in both experimental groups than the control (p < 0.05). The proximate chemical compositions of sea cucumber were less affected by the diets (p > 0.05). Compared with the control group, significantly elevated levels of digestive enzymes, antioxidants, and lysozyme, together with lower malondialdehyde levels, were recorded in the experimental groups (p < 0.05). ECP appeared to exhibit greater potency than EFS in enhancing growth performance and antioxidant capacity. Similar trends were observed in the mRNA expression of SOD, CAT, and inflammation-related genes across the groups. In a nutshell, both ECP and EFS supplemented in a low-fishmeal and low-soybean meal diet could effectively promote the growth and health of A. japonicus, with ECP showing a superior effect over EFS. These findings suggest that enzymatic hydrolysate demonstrates potential as a viable alternative to traditional fishmeal and soybean meal in diets for sustainable sea cucumber aquaculture. Further investigations are warranted to reveal its underlying mechanism. Full article