This study assessed the potential applicability of Moringa oleifera leaf meal (MO) and fermented Moringa oleifera leaf meal (FMO) as feed supplements for aquatic animals. Five experimental diets, including the basal diet (control), 2.2% and 4.4% MO-supplemented diets (MO2 and MO4), and 2.2% and 4.4% FMO-supplemented diets (FMO2 and FMO4), were prepared for feeding Megalobrama amblycephala juveniles. After the eight-week feeding trial, the growth performance, muscle nutritional composition, plasma and hepatic biochemistry indicators were measured. The results demonstrated that MO and FMO had no detrimental effects on the growth performance of M. amblycephala juveniles. The muscle crude protein, crude lipid, and total free amino acids contents were significantly enhanced in the FMO4 group (p < 0.05). The liver acetyl-CoA carboxylase α mRNA level was significantly increased and the lipoprotein lipase mRNA level was markedly reduced in the FMO4 group (p < 0.05). Therefore, the FMO4 group exhibited a significant increase in plasma low-density lipoprotein cholesterol and triglyceride levels (p < 0.05). Compared to the control group, total superoxide dismutase and catalase activities were significantly increased in the FMO4 group (p < 0.05). The FMO2 and FMO4 groups exhibited an anti-inflammatory response by inhibiting the expression levels of toll-like receptor 4, nuclear factor-kappa B, and tumor protein P53 mRNA (p < 0.05). In conclusion, the 4.4% FMO treatment increased muscle crude protein content, enhanced lipogenesis, and improved the hepatic antioxidant abilities of M. amblycephala juveniles, while 2.2% FMO and 4.4% FMO improved the liver anti-inflammatory capacities.

To investigate the mechanisms through which ferrous ion (Fe²⁺) addition improves the utilization of a cottonseed meal (CSM) diet, two experimental diets with equal nitrogen and energy content (low-cottonseed meal (LCM) and high-cottonseed meal (HCM) diets, respectively) containing 16.31% and 38.46% CSM were prepared. Additionally, the HCM diet was supplemented with graded levels of FeSO₄·7H₂O to establish two different Fe²⁺ supplementation groups (HCM + 0.2%Fe²⁺ and HCM + 0.4%Fe²⁺). Juvenile Ctenopharyngodon idellus (grass carps) (5.0 ± 0.5 g) were fed one of these four diets (HCM, LCM, HCM + 0.2%Fe²⁺ and HCM + 0.4%Fe²⁺ diets) for eight weeks. Our findings revealed that the HCM diet significantly increased lipid peroxide (LPO) concentration and the expression of lipogenic genes, e.g., sterol regulatory element binding transcription factor 1 (srebp1) and stearoyl-CoA desaturase (scd), leading to excessive lipid droplet deposition in the liver (p < 0.05). However, these effects were significantly reduced in the HCM + 0.2%Fe²⁺ and HCM + 0.4%Fe²⁺ groups (p < 0.05). Plasma high-density lipoprotein (HDL) concentration was also significantly lower in the HCM and HCM + 0.2%Fe²⁺ groups compared to the LCM group (p < 0.05), whereas low-density lipoprotein (LDL) concentration was significantly higher in the HCM + 0.2%Fe²⁺ and HCM + 0.4%Fe²⁺ groups than in the LCM group (p < 0.05). Furthermore, the plasma levels of liver functional indices, including alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glucose (GLU), were significantly lower in the HCM + 0.4%Fe²⁺ group (p < 0.05). Regarding the expression of genes related to iron transport regulation, transferrin 2 (tfr2) expression in the HCM group and Fe²⁺ supplementation groups were significantly suppressed compared to the LCM group (p < 0.05). The addition of 0.4% Fe²⁺ in the HCM diet activated hepcidin expression and suppressed ferroportin-1 (fpn1) expression (p < 0.05). Compared to the LCM group, the expression of genes associated with ferroptosis and inflammation, including acyl-CoA synthetase long-chain family member 4b (acsl4b), lysophosphatidylcholine acyltransferase 3 (lpcat3), cyclooxygenase (cox), interleukin 1β (il-1β), and nuclear factor kappa b (nfκb), were significantly increased in the HCM group (p < 0.05), whereas Fe²⁺ supplementation in the HCM diet significantly inhibited their expression (p < 0.05) and significantly suppressed lipoxygenase (lox) expression (p < 0.05). Compared with the HCM group without Fe²⁺ supplementation, Fe²⁺ supplementation in the HCM diet significantly upregulated the expression of genes associated with ferroptosis, such as heat shock protein beta-associated protein1 (hspbap1), glutamate cysteine ligase (gcl), and glutathione peroxidase 4a (gpx4a) (p < 0.05), and significantly decreased the expression of the inflammation-related genes interleukin 15/10 (il-15/il-10) (p < 0.05). In conclusion, FeSO₄·7H₂O supplementation in the HCM diet maintained iron transport and homeostasis in the liver of juvenile grass carps, thus reducing the occurrence of ferroptosis and alleviating hepatic lipid deposition and inflammatory responses caused by high dietary CSM contents.

This study aimed to investigate the effects of dietary tryptophan (Trp) on growth performance and muscle quality of Procambarus clarkii. Six experimental diets with graded Trp concentrations (0.05%, 0.13%, 0.29%, 0.43%, 0.56%, 0.69%; designated Trp0.05 to Trp0.69) were fed to crayfish for 8 weeks. Growth parameters, muscle proximate composition, texture, histology, related gene expression, and intestinal microbiota were measured. Compared with the Trp0.05 group, the Trp0.43 group significantly increased FW, WGR, SGR, and muscle crude protein content, while decreasing FCR. It also improved muscle texture (hardness, springiness, cohesiveness, gumminess, chewiness), increased muscle fiber diameter, and reduced fiber density and the proportion of fibers < 30 μm. Additionally, the Trp0.43 group upregulated mRNA expression of MEF2A, MEF2B, MLC1, MyHC, mTOR, S6K1, AKT, LARP6, Col1α1, Col1α2, TGF-β1, and Smad, and downregulated MSTN, 4EBP1, FOXO, and LC3. It reduced Proteobacteria and Shewanella abundance, and increased Bacteroidota and Firmicutes. In conclusion, appropriate dietary Trp improves P. clarkii growth, muscle quality, and intestinal microbiota. Based on quadratic regression analysis of WGR and SGR, the dietary Trp requirement of P. clarkii was estimated to be 0.39%, corresponding to 1.22% of feed protein.

The traditional use of iced trash fish (IF) in Chinese mitten crab (Eriocheir sinensis) aquaculture raises sustainability concerns, but the shift to formulated feeds (FF—a commercial compound feed specifically designed to meet nutritional requirements by blending multiple ingredients and containing a balance of nutrients) is often hindered by fears of compromising its prized flavor. This study aimed to comprehensively evaluate whether a commercial formulated feed could effectively replace IF without diminishing flavor quality, hypothesizing that FF would alter the intestinal volatile profile, thereby influencing muscle flavor. Male crabs were fed either IF or FF for eight weeks. Muscle flavor was assessed using sensory evaluation, electronic nose (E-nose), and gas chromatography–ion mobility spectrometry (GC–IMS). Volatile compounds in intestinal chyme were also analyzed by GC–IMS to explore potential transfer mechanisms. The results indicated that crabs fed with FF showed higher sensory scores for sweetness. Additionally, the E-nose analysis revealed a clear separation trend between dietary groups and showed markedly higher sensor response values for aromatic compounds, biogenically derived compounds and Maillard reaction products, sulfur-containing organic compounds, aliphatic hydrocarbons, total volatile organic compounds, alcohols and organic solvents, and alkenes in the FF group compared to the IF group. Thirty-four volatiles were discovered in the muscle. Statistical analysis (independent samples t-test) showed that the FF group exhibited significantly elevated levels of 3-methylbutanal-M, propanal, (E)-2-pentenal, 2,3-pentanedione, and pentan-1-ol-M, whereas the IF group exhibited significantly elevated levels of 2-hexanone, dihydro-2(3H)-furanone, butyl acetate, ethyl 2-methylpropanoate, and phenol (p < 0.05). Fourty-eight volatiles were identified in the intestinal chyme. Propanal and ethyl 2-methylpropanoate were the dominant odor contributors based on correlation network analysis. Strong correlations were identified between the flavor profiles of intestinal chyme and muscle, suggesting a potential transfer or transformation of volatiles. This work provides a scientific basis for optimizing aquafeed formulations to ensure sustainable crab production without sacrificing end-flavor quality.

Feed efficiency (FE) is one of the most economically and environmentally important target traits for genetic improvement since feed accounts for 50–70% of total production expenses in aquaculture worldwide. In addition to lowering production costs, reducing feed consumption per unit of biomass output also reduces emissions of nitrogen and phosphorus, which is in line with global sustainability goals for food production. The genetic framework of FE traits, molecular dissection of the targeted loci, conventional selective breeding frameworks, genomic selection, emerging biotechnological applications, major implementation challenges, and prospects are all covered in this review, which summarizes current developments in genetic improvement of FE in aquaculture. We incorporate empirical data from important farmed finfish and crustacean species, emphasizing that FE-related traits show measurable genetic variation available for selection, although reported heritability estimates vary substantially among traits, populations, phenotyping methods, and production conditions. Compared to conventional breeding techniques, the integration of high-throughput phenotyping, genomic prediction and multi-omics approaches has expanded opportunities to characterize FE variation and improve selection accuracy. However, most reported candidate loci and genes remain supported by associative rather than causal evidence, and functional validation in aquaculture remains limited. Integrated breeding approaches therefore offer feasible pathways to mitigate major constraints to genetic improvement of FE, although their practical application differs substantially among species and production systems.