Aquaculture Nutrition最新文献

This study evaluated the effect of four attractants on the growth performance, antioxidant capacity, immunity, and histology of largemouth bass larvae (Micropterus salmoides). A total of 75,000 larvae (~1.25 mg) were randomly divided into 15 tanks (five groups with three replicates), with 5000 larvae per tank. The experimental diets were isonitrogenous (54.45% crude protein) and isolipidic (13.20% crude lipid), including a control group (CON, no attractants), taurine (TAU) group (8 g/kg, trimethylamine oxide (TMAO) group (0.25 g/kg), dimethyl-β-propiothetin (DMPT) group (5 g/kg), and nucleotides (NTs) group (0.8 g/kg). The feeding trial was conducted in tanks (40 cm × 60 cm × 80 cm) for 21 days. The larvae were fed with Artemia three times daily for 7 days. The 21-day feeding trial started on the 8th day, alternated with feed six times daily from the 8th to 15th day, then fully transitioned to experimental diets with adjusted feed sizes. The results showed that TAU, DMPT, and NT groups significantly increased the final body weight (FBW), weight gain (WG), and specific growth rate (SGR) (p < 0.05), while TMAO, DMPT, and NT groups significantly increased the survival rate (SR) (p < 0.05), compared with the CON group. During the air stress challenge, compared with the CON group, all treatments significantly prolonged survival time (p < 0.05). Compared with the CON group, the TAU and NT groups significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) content, and decreased the malondialdehyde (MDA) content (p < 0.05), and the total antioxidant capacity (T-AOC) in the NT group was significantly increased (p < 0.05). All treatments significantly increased the activities of acid phosphatase (ACP) and alkaline phosphatase (AKP; p < 0.05). Compared with the CON group, the histological intestine indicated that all treatments significantly increased the intestinal fold height and decreased the muscular layer thickness, crypt depth, and fold width (p < 0.05); the histological liver indicated that the TMAO and NT groups could improve liver cells. In conclusion, all attractants exerted positive effects on largemouth bass larvae, with TAU, DMPT, and NT demonstrating significant growth enhancement associated with improved antioxidant capacity, immune response, and tissue histology. Further research is needed to clarify mechanisms and optimal doses.

Biofloc technology (BFT) has emerged as a sustainable aquaculture strategy, enabling high productivity with minimal water and land use. While diverse carbon sources are employed in BFT systems, identifying cost-effective and locally available alternatives can enhance profitability and adoption among farmers. This study evaluated the efficiency of five carbon sources, rice water (T1), jaggery (T2), sugar (T3), Eichhornia crassipes (T4), and a mixture of E. crassipes and jaggery (T5), compared to a control (CN) group without biofloc. Genetically improved farmed tilapia (GIFT) tilapia fry (10 fish per tank) were cultured for 60 days in triplicate tanks under controlled indoor conditions. After 15 days, all BFT treatments showed significantly higher weight gain than the CN (p  < 0.05). Although T2 achieved the highest weight gain overall, the differences from T4 and T5 were not significant by Days 45 and 60 (p  > 0.05). No significant differences were observed among BFT treatments in specific growth rate (SGR), daily weight gain, feed conversion ratio (FCR), or survival rate. Water quality parameters remained within optimal ranges, although total alkalinity declined across treatments from Day 15 onwards. Significant variation (p  < 0.05) was found in ammonia, nitrite, and nitrate concentrations among treatments throughout the trial. Floc volume (FV) increased steadily, peaking at Day 60 in the order T2 > T3 > T4 > T5 > T1. Floc porosity in T1 declined from 99.8% to 97.73%. Total solids were highest in T4 and T5. Bacterial counts were significantly greater in all BFT treatments compared to the CN (p  < 0.05). The results demonstrate that E. crassipes, alone or combined with jaggery, is an effective carbon source in BFT systems, supporting robust growth, microbial activity, and water quality. This approach offers an eco-friendly, low-cost strategy for improving the sustainability and economic viability of tilapia aquaculture.

The study investigated the effect of replacing soybean meal with faba bean in practical diets on growth performance, meat quality, intestinal microbiota, and muscle transcriptomics of Litopenaeus vannamei. In a practical feed with fish meal, soybean meal, and flour contents of 200, 250, and 250 g/kg (control group, FB0), 150, 300, and 450 g/kg of faba bean were used to substitute 30%, 60%, and 90% of the dietary soybean meal–flour mixture (1:1; FB15, FB30, and FB45). Thus, the contents of soybean meal and flour were reduced to 175, 100, and 25 g/kg, respectively, to form four isonitrogenous feeds. Shrimp with an initial body mass of 1.40 ± 0.07 g were fed with the above four feeds for 8 weeks. All four groups presented no significant difference in growth performance, including weight gain (WG), feed conversion ratio, feed intake, and protein efficiency ratio. When faba bean inclusion reached 300 g/kg (FB30 and FB45 groups), the total free amino acid and free flavor amino acid contents in flesh were significantly increased (p < 0.05), and the boiling loss in the FB30 group, the steaming loss, and the boiling loss in the FB45 group were significantly lower than those of the control group (p < 0.05). The flesh hardness and chewing of the FB45 group were also significantly higher than those of the control group (p < 0.05). When faba bean inclusion reached 450 g/kg, the abundance of intestinal Proteobacteria and Actinobacteriota was decreased, while the abundance of Firmicutes was increased. In addition, the high inclusion of faba bean promoted the expression of related pathways such as myosin and myogenic fibers, as well as the genes such as fibrillin-2 (FBN2), troponin C (TnC), and myosin regulatory light chain 2 (MRLC2). In conclusion, high dietary inclusion of faba bean improved the meat quality and almost completely replaced soybean meal without negative effects on the growth of Pacific white shrimp.

Fish meal replacement in aquaculture feeds requires supplementing functional additives to maintain animal performance. Nucleotides are a promising supplement in finfish, but their role in crustaceans remains poorly understood, particularly under challenging low-fish meal dietary conditions. This study evaluated dietary nucleotide supplementation effects on juvenile Chinese mitten crabs (Eriocheir sinensis) fed low-fish meal diets. Juvenile crabs (0.58 ± 0.01 g, first-year cohort) were distributed across 35 tanks with 1400 individuals total, creating seven dietary treatments (n = 5 replicates, 40 crabs per replicate). Over 56 days, crabs received either a control diet (35% fish meal) or six low-fish meal diets (15% fish meal) supplemented with graded nucleotide concentrations (0, 0.3, 0.6, 0.9, 1.2, or 2.4 g/kg). Nucleotide supplementation increased feed intake in a dose-dependent manner (p < 0.05); at 0.9 g/kg, intake was restored to the control level (p > 0.05). This higher intake coincided with increased digestive enzyme activities (α-amylase (α-Ams), trypsin (Try), and lipase) and improved growth (weight gain and specific growth rate; p < 0.05), with 0.9 g/kg or higher restoring growth to levels not significantly different from the high-fish meal control. Mechanistically, supplementation restored intestinal health by preserving morphology and lowering inflammation-related gene expression. Furthermore, it bolstered hepatopancreatic antioxidant defenses (a key transcriptomic finding) and favorably restructured the gut microbiota, which correlated with host performance (p = 0.007). Thus, nucleotide supplementation mitigates the adverse effects of low-fish meal diets by improving feed intake and intestinal health. The optimal level for growth was 0.85 g/kg based on broken-line regression.

The use of natural antioxidants (NAOXs) to prevent feed oxidation and reduce oxidative stress in fish is gaining momentum in the aquafeed industry. As sustainable alternatives to synthetic antioxidants like ethoxyquin (banned) and butylated hydroxytoluene (BHT)/butylated hydroxyanisole (BHA) (under scrutiny), NAOX (particularly polyphenols) require assessment for their stability during feed production and their biological effects on fish. This study followed four natural polyphenols (NPs) in a plant-based ingredient, which was then incorporated into a standard feed. The polyphenols were tracked through various processing stages (ingredients, diet mix, extrusion, drying, and storage) and in fish tissues (liver and muscle) using liquid chromatography mass spectrometry. Post-smolt Atlantic salmon were fed diets containing 0.00%, 0.01%, or 0.05% of the polyphenol-rich ingredient for 100 days. NAOX supplementation led to increased levels of astaxanthin, α-tocopherol, and γ-tocopherol, and reduced thiobarituric acid reactive substance (TBARS) in the feed, indicating improved oxidative stability. In the fish, NAOX had no effect on growth, organ indices, cataracts, or fillet color. However, it significantly reduced malondialdehyde (MDA) levels in liver and muscle and lowered hepatic glutathione (GSH), suggesting improved antioxidant protection. Among the four NPs, only three were consistently detected in fish tissues, especially in the liver. Although extrusion caused substantial losses, the polyphenol profiles in feed and tissue reflected those of the original ingredient. This is the first study to trace NAOXs throughout the entire production chain in salmon aquaculture. The findings support the use of NAOX to enhance feed stability and fish oxidative resilience in a sustainable and effective manner.

Reproductive maturation remains a central bottleneck in crustacean aquaculture, as ovarian development dictates broodstock quality, fecundity, and larval viability. This review synthesizes current knowledge on the physiological regulation of ovarian maturation in decapod crustaceans, emphasizing the interplay of hormones, nutrients, and environmental factors. Eyestalk-derived neuropeptides of the crustacean hyperglycemic hormone (CHH) family, together with molt-inhibiting hormone (MIH), vitellogenesis-inhibiting hormone (VIH), methyl farnesoate (MF), and ecdysteroids, constitute the core hormonal regulators, with CHH and MF promoting vitellogenesis while VIH exerts inhibitory control. Among nutritional drivers, proteins, amino acids (notably arginine), long-chain polyunsaturated fatty acids (LC-PUFAs), cholesterol, and carotenoids exert the most pronounced effects on vitellogenesis, oocyte maturation, and larval quality, with their regulatory roles frequently mediated through endocrine pathways such as mTOR and steroidogenesis. Evidence across species indicates that optimal ovarian growth is generally achieved at dietary protein levels of 30%–35%, lipid levels of 8%–12%, and specific amino acid concentrations including 2.5%–4.5% arginine, 0.6%–1.0% taurine, and 1.5%–1.7% threonine. Favorable temperature and photoperiod can regulate ovarian development better and lead to higher spawning rates and reproductive effects compared to salinity. Finally, the economic feasibility of nutritional interventions is evaluated, highlighting that while cholesterol and krill oil are biologically effective, their high cost necessitates strategic use alongside sustainable alternatives such as phytosterols, marine by-products, and plant- or insect-based proteins. By consolidating hormonal, nutritional, and environmental perspectives, this review outlines regulatory mechanisms of ovarian development while identifying practical strategies to improve broodstock management and reproductive efficiency in crustacean aquaculture.

Ellagic acid (EA), in pure form or extracted from pomegranate (Punica granatum) peel (PP), is a bioactive polyphenol that provides strong anti-inflammatory and antioxidant effects in cultured fish. To investigate the benefit and any adverse effects of PP as a source of EA, and pure EA by assessing growth parameters, digestive enzymes, antioxidant, and immune factors when supplied to 450 juvenile Oreochromis niloticus (10.4 ± 0.9 g) over 60 days. Feeding treatments used a standard feed with EA included at three concentrations (i.e., 0.1, 0.15, and 0.2 g kg⁻¹) and PP at three concentrations (i.e., 10, 15, and 20 g kg⁻¹) and in combination with similar doses (i.e., EP 1 = 50 mg + 5 g kg⁻¹, EP 1.5 = 75 mg + 7.5 g kg⁻¹, and EP 2 = 100 mg + 10 g kg⁻¹ to keep the EA content around 0.1, 0.15, 0.2 g kg⁻¹, respectively) as well as a control without inclusion. The final weight (FW) of the fish was significantly increased in most treatments compared to the control group (p < 0.05). White blood cell (WBC) counts increased in higher dose treatments for both EA and EP (i.e., EA 0.2 g, EP 1.5, and EP 2). Antioxidant and key digestive enzyme (protease, lipase, and α-amylase) activities were generally elevated, with most treatments showing significant (p < 0.05) increases in the transcription of glutathione genes or activity of superoxide dismutase (SOD), catalase (CAT), and a decrease in the malondialdehyde (MDA). Immune responses showed significant increases in immunoglobulin M (IgM), lysozyme, and respiratory burst activity (RBA), and the expression of immune genes in several treatments. Notably, EA at 0.2 g and EP 2 elicited a stronger response than the other dosages for these parameters in Nile tilapia. These findings suggest that dietary supplementation with EA, PP, or their combination enhances growth performance, immune responses, and antioxidant capacity in O. niloticus, with the EA 0.2 g and EP 2 treatments showing the most pronounced effects.

Carbohydrates in aquaculture feeds can induce metabolic disturbance when exceeding fish utilization capacity, leading to lipid accumulation and insulin resistance. Bitter melon (BM; Momordica charantia), rich in saponins, flavonoids, and polysaccharides, shows potential as a functional feed additive for glycemic control and lipid metabolism modulation. This investigation systematically assessed the effects of BM powder (BMP) supplementation (at 0.5%, 1%, and 1.5%) in high-starch (HG) diets for Cyprinus carpio. Compared to the HG group, BMP supplementation significantly reduced serum glucose (GLU) and triglycerides (TGs), while elevating total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C). The BMP group exhibited reduced malondialdehyde (MDA), enhanced antioxidation ability, and mitigated hepatopancreatic and intestinal histopathological damage from carbohydrate overload. Meanwhile, BMP restored muscle C20:3n−6 and C22:6n−3 (DHA) levels decreased by HG diets. Notably, 1.5% BMP decreased hepatopancreatic and muscular glycogen/lipid deposition, induced by a high-carbohydrate diet. Gene expression analysis revealed BMP upregulated glycolysis-related genes (glucokinase [gk], pyruvate kinase [pk], and pfk) across tissues (hepatopancreas, muscle, intestine, and adipose tissue), while suppressing glycogen synthesis (gys) and gluconeogenesis (g6pase) genes. Besides, lipid biosynthesis genes were downregulated, corroborating reduced ectopic lipid storage. Taken together, these findings demonstrate that BMP supplementation significantly improves glycemic control, lipid metabolism, and antioxidant capacity in common carp. This suggests that BMP could serve as a natural, sustainable aquafeed additive to counter metabolic syndrome in intensively farmed fish.

Host-derived probiotics offer sustainable alternatives to the commercial nonaquatic formulations due to superior compatibility with the gastrointestinal environment of aquatic species. This study integrated: (i) isolation, identification (via 16S rRNA sequencing), and in vitro potentiality (pH and bile tolerance) of gut-derived bacteria from wild M. rosenbergii, and (ii) an in vivo 120-day aquarium trial to evaluate performance of these laboratory-isolated probiotics (T1) compared to a commercial probiotic formulation (T2), and a control group fed with no probiotics (T0). Nine bacterial isolates were identified, including Bacillus cereus, Enterococcus faecium, Glutamicibacter mysorens, and Staphylococcus succinus, which exhibited strong acid and bile tolerance. In vivo, probiotic treatments improved water quality by reducing ammonia and stabilizing pH, ammonia was significantly lower in T1 (0.28 ± 0.03 mg/L) than in T0 (0.36 ± 0.06 mg/L; p < 0.05). Growth performance was enhanced with probiotics: final average weights reached 3.92 ± 0.08 g in T1, 3.17 ± 0.06 g in T2, and 2.31 ± 0.13 g in T0. Specific growth rate (SGR) was significantly higher in T1 (2.87% ± 0.03%) compared to T0 (2.36% ± 0.05%). Feed conversion ratio (FCR) was lowest in T1 (0.32 ± 0.09) and highest in T0 (1.13 ± 0.14), while feed conversion efficiency (FCE) was highest in T1 (3.15 ± 0.50). Overall, laboratory-isolated/host-derived probiotics outperformed the commercial formulations by simultaneously enhancing growth, feed utilization, and water quality, emphasizing their usefulness as a species-specific, sustainable alternative for freshwater prawn aquaculture.