Aquaculture Nutrition最新文献

Although silver pomfret (Pampus argenteus) is a highly valued marine fish in China, its aquaculture development is limited by the lack of species-specific formulated feed. This study investigated the effects of replacing fishmeal with Antarctic krill (Euphausia superba) meal (AKM) on the nutritional deposition, metabolism, and immune response of silver pomfret. Juvenile fish with an initial body weight of 12.93 ± 0.48 g were randomly allocated into four dietary treatments with three replicates per treatment (50 fish per tank; 600 fish in total), and fed one of four experimental diets containing 0% (FM), 10% (KM10), 20% (KM20), or 40% (KM40) AKM for a 60-day feeding trial. The results showed that moderate AKM inclusion, particularly at the 20% replacement genes (pparα, cpt1α) and the downregulation of lipid level significantly enhanced intestinal trypsin and lipase activities, as well as glucose and amino acid metabolic capacity. In addition, lipid utilization efficiency was improved through the upregulation of fatty acid oxidation-related genes (fas). Consequently, the KM20 group exhibited significantly higher muscle essential amino acids and polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), compared to the FM group (p < 0.05). Furthermore, serum immunoglobulin M (IgM), complement C3, and C4 levels increased in AKM-fed groups, with KM20 showing the most pronounced enhancement. However, excessive substitution (KM40) led to a decline in certain nutritional and immune parameters, suggesting potential metabolic imbalances. These findings indicate that moderate replacement of fishmeal with AKM (~20%) optimizes nutrient deposition, enhances metabolic efficiency, and boosts immune capacity in silver pomfret. This study provides a theoretical basis for the development of functional aquafeeds aimed at promoting the sustainable and efficient industrial cultivation of silver pomfret.

This research aimed to explore the impact of bile acid (BA) supplementation in low fishmeal diets on growth performance, serum biochemical indices, tissue morphology, lipid metabolism, gene expression, and gut microbiota in triploid rainbow trout (Oncorhynchus mykiss, initial weight 15.97 ± 1.4 g). The experimental design involved a low fishmeal diet (10%), and four treatment groups with BA additions (0.05%, 0.10%, 0.15%, and 0.20%) to the basal diet. The findings indicated that the group receiving 0.10% BA (G3) exhibited an enhancement in final body weight (FBW), specific growth rate (SGR), weight gain rate (WGR), and condition factor (CF), significantly outperforming the control group (G1, p < 0.05). 0.10% BA addition significantly increased whole-body crude protein and lipid content. (p < 0.05). Serum analysis showed a significant reduction in total bilirubin (TBIL) and triglycerides (TG), and an increase in BA and lipoprotein cholesterol (LDL-C) in the G3 group compared to G1 (p < 0.05). The 0.10% BA supplementation downregulated pro-inflammatory gene expression, like il-1β, and upregulated lipid metabolism-related genes, like scdb, in the intestinal tract of O. mykiss (p < 0.05). 16S high-throughput sequencing identified key microbial groups in the intestine of O. mykiss, highlighting significant differences in microbial composition with BA supplementation. Metabolomic analysis revealed that BA addition altered the metabolic profile of O. mykiss, affecting pathways such as polycyclic aromatic hydrocarbon (PAH) catabolism, cysteine (Cys) and methionine (Met) metabolism, the sulfur relay system, arachidonic acid (AA) metabolism, and ovarian steroidogenesis. In summary, a 0.10% BA addition to the diet of O. mykiss significantly improved growth performance, mitigated intestinal inflammation in specimens fed low fishmeal diets, and promoted overall gut health and lipid metabolism.

In this study, the effect of dietary taurine (Tau) on the innate immune responses, digestive function, and mammalian target of rapamycin (RAPA; mTOR) signaling was investigated in coho salmon (Oncorhynchus kisutch). Coho salmon were fed diets supplemented with 0, 0.2, 0.4, and 0.6 g/kg Tau for 8 weeks. The results demonstrated that the activity of antioxidant enzymes was enhanced, while reactive oxygen species (ROS) production was reduced by dietary Tau in the small intestine. Furthermore, Tau supplementation altered the homeostasis of essential nutrients, including Na, K, and Ca. Dietary Tau enhanced intestinal barrier function by upregulating tight junction proteins, including occludin, ZO-1, and claudin-18 gene expression. Dietary Tau also upregulated the gene expression of inflammatory cytokines such as IL-1β, TNFα, and IL-6, as well as the gene expression related to mTOR signaling pathway. Notably, Tau positively influenced intestinal villus morphology and trypsin activity and increased levels of free amino acids. In addition, the mTOR inhibitor RAPA was used to reveal mTOR's role in regulating the expression of molecules associated with innate immune responses. The results showed that RAPA treatment suppressed the gene expression related to antioxidant enzymes and intestinal tight junction. In conclusion, Tau could modulate innate immune responses, digestive function, and intestinal barrier integrity, and mTOR may play a role in regulating these physiological processes in the small intestine of coho salmon.

Several factors are known to affect the substitution of fish meal (FM) in aquafeeds, yet the influence of dietary fatty acid (FA) composition remains unclear. To investigate this, fish oil (FO), an FA-optimized blended oil (BO1) designed to meet the essential FA (EFA) requirements of largemouth bass (Micropterus salmoides), and a blend rich in n-6 polyunsaturated FAs (PUFAs) (BO2, a 2:3 mixture of FO and soybean oil) were used as dietary lipid sources. Three isoproteic (50%) and isolipidic (9%) diets with distinct FA profiles were formulated at either 24% (24FO, 24BO1, and 24BO2) or 16% (16FO, 16BO1, and 16BO2) FM inclusion levels. Juvenile fish (initial weight about 12.50 g) were fed the diets for 10 weeks. Results showed no significant differences in growth performance among the 24% FM groups. At the 16% FM level, the 16BO1 group exhibited growth comparable to the 16FO group and achieved significantly higher final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) than the 16BO2 group (p < 0.05). Moreover, compared to 16BO2, the 16BO1 group demonstrated improved lipid metabolism (indicated by reduced hepatosomatic index [HSI], viscerosomatic index [VSI], triglycerides [TGs], nonesterified FAs [NEFAs], and blood urea nitrogen [BUN]), enhanced protein synthesis (reflected in increased total amino acids [TAAs], alanine transaminase [ALT], and aspartate transaminase [AST]), elevated antioxidant capacity (total antioxidant capacity [T-AOC] and catalase [CAT]), and upregulated mRNA expression of genes related to lipid oxidation (pparα, atgl, and acsl4) and protein synthesis (akt2 and eif4g). These findings demonstrate that optimizing dietary FA composition enhances FM substitution efficacy by promoting lipid-based energy supply, improving protein synthesis, and strengthening antioxidant responses. This study is the first to reveal that dietary FA profiles modulate FM replacement efficiency in aquatic feeds, providing new insights and viable strategy for developing low-FM diets to promote sustainable largemouth bass aquaculture.

Viral diseases represent one of the major threats to the global aquaculture industry. In recent years, the relationship between gut microbiota and viral infections in fish has garnered increasing attention. The gut microbiota contributes critically to fish health and is involved in antiviral defense through immune regulation, secretion of microbial metabolites, as well as enhancement of barrier function. The gut microbiota, host immunity, and viral infection form a complex and dynamic interaction network. A substantial body of 16S rRNA and metabolomics correlation studies has indicated that viral infections can alter the gut microbiota in fish, while changes in the gut microbiota can, in turn, influence viral infection. In this review, we summarize the regulatory effects of gut microbiota on fish viral infections, explore the interactions between the gut microbiota, immune system, and viral pathogenesis, and discuss future research directions and potential application prospects. By outlining the three-dimensional interaction network of "microbiota-immune-virus" in fish, this review not only lays a theoretical foundation for developing targeted microecological strategies for green disease control but also provides an evolutionary perspective for understanding host-microbe coevolution in vertebrates.

Nutritional programming (NP) of n-3 polyunsaturated fatty acids (PUFAs), achieved by injecting linseed oil into Nile tilapia alevins, influences lipid profiles and associated metabolic processes during the juvenile stage. However, the persistence of these effects into adulthood is unknown. In this study, we investigated the long-term NP effects of early n-3 PUFA and n-3 long-chain (LC)-PUFA intervention via linseed and fish oil injection, respectively, during the alevin stage on lipid metabolism and associated pathways in adult Nile tilapia. The experimental design included randomized treatment groups of 0.85% NaCl (control), linseed oil, and fish oil, each with six replicates. Linseed and fish oil were microinjected into the yolk reserves of Nile tilapia alevins, while control fish received NaCl injections. Following dietary challenge with a linseed oil-rich diet (weeks 37-40), linseed oil-injected fish exhibited higher weight gain, suggesting that early linseed oil enrichment enhanced n-3 PUFA utilization for growth. Both interventions reduced plasma lipemia, promoted hepatic fat accumulation, and downregulated mlxipl and acaca expression in the muscle, potentially modulating interactions between carbohydrate and lipid metabolism. While these effects were more pronounced in the fish oil-injected group, long-term NP effects differed between the liver and muscle, including decreased hepatic but increased muscular n-3 LC-PUFA deposition, and downregulated hepatic but upregulated muscular β-oxidation in fish oil-injected adult fish. Gene expression analysis revealed altered hepatic enzymes involved in DNA (de)methylation and histone modification, implicating epigenetic mechanisms in the long-term NP effects of early n-3 PUFA and n-3 LC-PUFA exposure. Thus, linseed and fish oil enrichment during the alevin stage induces long-term alterations in lipid metabolism and enhances muscular n-3 LC-PUFA deposition in adult Nile tilapia.

This study examines the nutritional profile of European flat oysters (Ostrea edulis) cultivated in an Integrated Multi-Trophic Aquaculture (IMTA) system in Gaeta, Italy. Oysters were deployed for 257 days, 8 July 2023-21 March 2024, at two distances from gilthead seabream (Sparus aurata) cages: 20 m, representing high exposure to fish-derived waste, and 800 m, reflecting reduced waste influence and greater phytoplankton availability. The objective was to evaluate how proximity to fish cages, combined with seasonal variability, influences oyster nutritional quality and to identify optimal spatial arrangements in IMTA systems. Sampling occurred in summer, autumn, winter, and spring to capture seasonal changes in physiology and nutrition. Oysters at the distant site showed consistently higher nutritional quality, attributed to greater phytoplankton access and dilution of fish waste. Crude protein content ranged from 4.49% to 7.81%, with the highest values recorded at the distant site. Crude lipid levels peaked at 1.31% in March, linked to prereproductive nutrient accumulation. Arginine and lysine were the most abundant essential amino acids (EAAs), with significantly higher arginine levels at the distant site during late autumn and early spring. These findings emphasize the spatial planning and seasonality in IMTA, supporting sustainable aquaculture, ecosystem services, and nutrient-rich seafood production.

Since shellfish farming has the potential to help feed a growing human population, it is crucial to anticipate new opportunities to improve the health of bivalves on farms and hatcheries. Phycobiliproteins (PBPs), natural nutritional components, are considered promising as immunomodulatory feed additives for aquaculture. The aim of this study was to examine the acute toxicity of a PBP extract obtained from Arthrospira platensis biomass for commercially important bivalve species, the Pacific oyster (Magallana gigas (Thunberg, 1793)). The PBP extract was added to water at final concentrations of 2, 20, and 200 μg/mL for a 24 and 48-h exposure period. Compared to the control group, there were no treatment-related biological effects on oyster mortality or induction of apoptosis or cellular death of hemocytes. However, exposure to the PBP extract significantly increased the respiratory rate of the oysters for 24-48 h. In the high-dose group (200 μg/mL), a reduction in the activity of nonspecific cytoplasmic esterases and an increase in DNA damage levels in hemocytes were observed. Examinations of heat shock protein expression (HSP70 and HSP90) in the gills showed up-regulation of HSP90 at a 200 μg/mL extract concentration after a 24 h exposure period and at all studied concentrations after 48 h of exposure. Although oysters in the high-dose group displayed signs of genotoxicity and reduced nonspecific esterase activity of hemocytes, other parameters measured indicated low toxicity of the extract. The no-observed-adverse-effect level of the PBP extract for adult Pacific oysters was determined as a concentration in water below 200 μg/mL.

Calcium and magnesium are essential mineral elements for animal growth and development, playing crucial roles in skeletal formation, particularly in the molting process of crustaceans. However, their interaction is still poorly elucidated. This study investigated the effects of dietary calcium and magnesium levels on the growth performance, tissue deposition of calcium and magnesium, exoskeleton development, and molting performance of Chinese mitten crab (Eriocheir sinensis). A 2 × 4 factorial design was adopted to formulate eight experimental diets, comprising two targeted calcium levels (1% and 2%) and four targeted magnesium levels (0.15%, 0.3%, 0.45%, and 0.6%). These diets were fed to crabs with an initial body weight of 40.46 ± 0.47 g for a 10-week period. The results showed that increased dietary calcium levels significantly reduced the weight gain rate (WGR), hepatosomatic index (HSI), carapace hardness, tissue (hepatopancreas, intestine, and muscle) calcium content, the expressions of genes related to calcium and magnesium absorption in the hepatopancreas, and the expressions of genes associated with molting and exoskeleton development. In contrast, it decreased the levels of molting hormone in hemolymph, chitinase (CHI) activity in the epidermis, and the expressions of genes encoding the molting hormone receptor and CHI in the hepatopancreas. The highest WGR was observed at a magnesium level of 0.6%, which also significantly enhanced carapace hardness and methyl farnesoate (MF) content in hemolymph, but significantly suppressed the expressions of chitin synthase genes in the hepatopancreas. Moreover, at 1% calcium level groups, increased dietary magnesium levels significantly upregulated the expressions of magnesium absorption-related genes. At 2% calcium level groups, with increasing dietary magnesium levels, the expressions of intestinal calcium absorption-related genes initially decreased then increased, while those of hepatopancreas calcium absorption-related genes significantly increased. Furthermore, significant interactive effects between dietary calcium and magnesium levels were observed on WGR, carapace hardness, collagen fiber content, CHI activity, and molting hormone levels in hemolymph. In conclusion, the interaction between dietary calcium and magnesium levels significantly influenced the growth performance, exoskeleton development, and molting of E. sinensis. An increase in dietary calcium levels should be accompanied by an appropriate elevation in magnesium levels in formulated feeds for this species.

The global transition toward low-fishmeal formulations has intensified the search for sustainable and digestible protein alternatives in shrimp aquaculture. Enzymatically hydrolysed feather meal (HFM) represents a promising high-protein ingredient with enhanced digestibility and bioactive potential. This study evaluated the effects of graded HFM inclusion (0%–5%) on growth performance, digestive enzyme activity, antioxidant status, and muscle composition of Penaeus vannamei juveniles. Five isonitrogenous (40.2 ± 1.9% crude protein) and isolipidic (12.3 ± 1.4% crude lipids) diets were formulated with 0%, 1.25%, 2.5%, 3.75%, and 5.0% HFM, replacing part of the soybean meal while maintaining a constant fishmeal inclusion (6%). A total of 100 shrimp (initial weight 1.2 ± 0.1 g; initial length 4.3 ± 0.3 cm) were randomly distributed into 20 tanks (4 tanks per diet; 20 shrimp per diet) and reared for 50 days under controlled clear-water conditions. Growth performance, feed efficiency, digestive and antioxidant enzyme activities, and abdominal muscle composition were analysed using one-way ANOVA and polynomial regressions. Growth and feed conversion ratio were unaffected by HFM inclusion (p > 0.05). Lipase, cellulase, and carbohydrate-digesting enzymes remained stable, while trypsin and chymotrypsin showed a mild increase at 1.25%–2.5% inclusion. Glutathione peroxidase activity tended to increase (p = 0.10), whereas reduced glutathione was significantly lower in all HFM-fed groups (p < 0.001). Lipid peroxidation (TBARS) and glutathione reductase remained unchanged. Muscle protein and moisture were unaffected, while ether extract showed a modest but significant increase (p < 0.001). In conclusion, enzymatically HFM can be safely incorporated up to 5% in low-fishmeal diets for P. vannamei without impairing growth, digestive function, antioxidant defence, or flesh composition, supporting its potential as a sustainable ingredient for modern shrimp feeds.