Aquaculture Nutrition最新文献

This study investigated how partially replacing fishmeal (FM) with silkworm pupae (SWPs) (Bombyx mori) and yellow mealworm (MW) larvae (Tenebrio molitor) affects the growth, health, and metabolism of Siberian sturgeon (Acipenser baeri). Four experimental diets were tested: a control with 60% FM and no insect meal, 45% FM with 15% MW, 45% FM with 15% SWPs, and a combined diet containing 45% FM plus both insect proteins: 7.5% MW, as well as 7.5% SWPs (SMW). Fish were reared under controlled conditions, including water temperature 18 ± 1°C, dissolved oxygen 8.5–9.3 mg L⁻¹, pH 7.6, and a fixed feeding regime. Sturgeon fed MW and SMW diets showed significantly improved growth, higher final weight, better specific growth rate (SGR), and more efficient protein utilization, along with a lower feed conversion ratio (FCR) compared to the control. Sturgeon fed MW and SMW diets showed significantly improved growth, higher final weight, better SGR, and more efficient protein utilization, along with a lower FCR compared to the control. Digestive enzyme activities (amylase [AMS], protease, lipase [LP]) and key serum metabolites—including protein, albumin, cholesterol, triglycerides, and glucose—were elevated in insect-fed groups. Immune and antioxidant defenses, such as lysozyme, immunoglobulin M (IgM), glutathione peroxidase (GPX), and superoxide dismutase (SOD), were enhanced, particularly in the SMW and MW treatments, while oxidative stress markers (malondialdehyde [MDA]) were favorably modulated. Gene expression analysis revealed upregulation of growth-related (growth hormone [GH], IGF1), protein metabolism (target of rapamycin [TOR]), lipid metabolism (Apolipoprotein [ApoE]), and immune genes (interleukin-1 [IL-1]), with the strongest response in the combined SMW diet. Overall, partially replacing FM with insect meals, especially the MW and SWP combination, effectively supports growth, metabolism, immune function, and antioxidant capacity in Siberian sturgeon. These findings highlight the promise of insect-based proteins as a sustainable and effective alternative in Siberian sturgeon aquaculture.

Due to stagnant production and high cost of fish meal (FM), feed nutritionists are seeking reliable and affordable alternatives. However, low-FM diets often result in poor palatability, reduced feed consumption (FC), and impaired growth. This study investigates the effects of replacing FM with plant proteins in diets with or without jack mackerel meal (JMM) inclusion on the growth performance of juvenile red sea bream (P. major). A three-way {2 FM replacement sources (corn gluten meal [CGM] and soy protein concentrate [SPC]) × 2 FM replacement levels (20% and 40%) ×2 JMM inclusion (without and with)} ANOVA experimental design was applied. The control (Con) diet contained 60% FM. In the Con diet, 20% and 40% FM were replaced with CGM and SPC without or with 24% JMM inclusion, named the CGM20, CGM40, SPC20, SPC40, CGM20J, CGM40J, SPC20J, and SPC40J diets, respectively. A total of 675 juvenile fish were assigned into 27 tanks. Weight gain (WG), specific growth rate (SGR), and FC of fish fed the CGM-replaced diets were significantly higher than those of fish fed the SPC-replaced diets. Furthermore, dietary replacements of 20% FM achieved significantly higher WG, SGR, and FC in fish compared to those of 40% FM. Additionally, WG, SGR, and FC of fish fed the all-plant-protein-replaced diets with JMM inclusion were significantly higher than those without JMM inclusion. WG, SGR, and FC of fish fed the Con diet were significantly higher than those of fish fed the CGM40, SPC20, SPC40, CGM40J, and SPC40J diets. In conclusion, up to 20% of FM can be replaced by CGM, with or without JMM inclusion, or by SPC with JMM inclusion in a 60% FM-based diet without significantly impairing the growth performance of red sea bream.

An 8-week feeding trial was conducted to evaluate the feasibility of substituting soybean meal (SBM) with degossypolized cottonseed protein (DCP) on Hefang bream. Five iso-nitrogenous and iso-lipidic diets were formulated with graded replacement levels of SBM by DCP at 0% (control), 25% (DCP25), 50% (DCP50), 75% (DCP75), and 100% (DCP100). Results showed that DCP could effectively replace up to 50% of dietary SBM in Hefang bream, without adverse influence on survival rate and growth performance. However, the specific growth rate in fish fed diets with DCP replacing 75% and 100% of SBM decreased significantly. Muscle essential amino acid profiles showed marked reductions in isoleucine, leucine, and lysine concentrations in fish fed diets with DCP replacing 75% and 100% of SBM, correlating with suppressed mTOR pathway transcription. The intestinal villi length and the intestinal trypsin activity in fish fed diets with DCP replacing 75% and 100% of SBM were significantly lower than those in the control group. The total antioxidant capacity and catalase activity in fish fed the diet with DCP replacing 100% of SBM were significantly lower than those in the control group. The mRNA expression of hepatic inflammatory cytokines in fish fed the diet with DCP replacing 25% of SBM was the lowest among the groups. In conclusion, these findings suggest that DCP can replace up to 50% of SBM in diets of the Hefang bream without compromising the growth performance. However, excessive dietary DCP (75%–100%) can induce protein utilization impairment, digestive dysfunction, oxidative stress, and hepatic inflammation.

Fish are believed not to synthesize vitamin D through UV exposure but to meet their requirements from dietary sources. The high vitamin D levels found in many fish species are thought to originate from UV-induced synthesis in plankton, with vitamin D subsequently accumulating through the aquatic food chain. Atlantic salmon is a rich dietary source of vitamin D, but limited data exist on circulating vitamin D levels. To address this, plasma levels of the three main vitamin D metabolites were measured in Atlantic salmon from Norwegian fish farms using mass spectrometry. Here, we show that salmon reared in open sea pens have significantly higher vitamin D levels than those raised indoors. Monitoring an outdoor farm over 18 months revealed a distinct seasonal pattern between vitamin D levels and day length. In a follow-up experiment, indoor-raised fish were divided into two groups: one remained indoors, while the other was transferred outdoors for 52 days. Both groups received the same commercial feed, yet the outdoor group exhibited a fivefold increase in whole-body vitamin D content. These surprising findings provide field evidence of endogenous vitamin D synthesis in fish induced by natural sunlight. This discovery could have important implications for aquaculture, emphasizing the risk of suboptimal vitamin D levels in farmed fish when sunlight exposure is limited.

This study investigated the mitigating effects of alanyl-glutamine (AG) on soybean-meal-induced enteritis (SBMIE) in largemouth bass (Micropterus salmoides). Three experimental diets were prepared: a fishmeal (FM) diet as a positive control, a 50% soybean meal (SBM) replacement FM protein (SBM50) diet as a negative control, and the SBM50 diet supplemented with 1% AG (SBM50 + 1% AG). Fish (initial weight: 10.20 ± 0.20 g) were distributed into three groups in triplicate (25 fish per tank) and fed for 8 weeks. Results demonstrated that the SBM50 + 1% AG group exhibited markedly higher final body weight, weight gain rate, and specific growth rate compared to the SBM50 (p < 0.05). The SBM50 + 1% AG group markedly elevated serum levels of free glycine, lysine, and total essential amino acids compared to the FM group (p < 0.05). In addition, the SBM50 + 1% AG group markedly increased the intestinal plica height (PH) and goblet cell numbers compared to the SBM50 group (p < 0.05). Pathological alterations, including villous atrophy, nuclear pyknosis, mitochondrial matrix dissolution, and inner membrane disruption, were shown in the SBM50 group, all of which were ameliorated by AG supplementation. In addition, the addition of AG significantly reduced Caspase3 activity compared to the FM group (p < 0.05). Microbiome analysis revealed dietary AG significantly increased α-diversity and the proliferation of potentially beneficial taxa (Bacteroidota, Bacteroides, and Prevotella) (p < 0.05). Transcriptomics showed dietary AG upregulated intestinal barrier-related pathways (including focal adhesion, cell adhesion molecules, and adherens junction), along with tight junction gene expression (zo-1, claudin-3, and filamin-B). In conclusion, high dietary SBM inclusion impairs growth performance and induces intestinal inflammation in largemouth bass. Dietary AG effectively mitigates SBMIE by remodeling the intestinal microbiota, enhancing intestinal barrier integrity, and modulating immune responses.

In this study, five levels of waste wet dates (WDs) (Phoenix dactylifera) (0%, 5%, 10%, 15%, and 20%) were added to the diets of Nile tilapia (Oreochromis niloticus) and thin-lip gray mullet (Liza ramada) in order to assess their growth, feed performance, whole-body composition, fatty acids (FAs), intestinal enzyme activity, and biochemical blood parameters in a polyculture system. In 15 concrete tanks of 2 m × 5 m × 1 m, five dietary treatments were set up, each in triplicate, with 15 Nile tilapia (10.3 g) and 5 thin-lip gray mullet (5.0 g) fingerlings per tank. The fish were fed a diet that contained ~30% crude protein (CP) for 60 days. The growth and feed utilization of Nile tilapia were all significantly improved by feeding them 10% WD, while thin-lip gray mullet benefited most from feeding 15% WD. According to the blood parameter data, the lowest levels of triglycerides, amylase, and glucose were seen in Nile tilapia fed 10% dietary WD. Furthermore, the 15% WD diet enhanced the polyunsaturated FA (PUFA) profile in mullet flesh. On the other hand, as compared to the other groups, thin-lip gray mullet fed 20% dietary WD had the greatest levels of glucose and amylase.

Phytochemicals derived from plants have attracted attention as feed additives in aquaculture due to their natural bioactive properties. These compounds have a wide range of benefits such as improving fish growth, increasing feed efficiency, and enhancing immunity. As natural alternatives to synthetic chemicals and antibiotics, phytochemicals contribute to disease resistance, reducing oxidative stress, and promoting gut health in aquatic animals. Betaine, a natural compound with osmotic and metabolic functions, has become a suitable feed additive in aquaculture due to its potential benefits for fish health. The role of betaine in maintaining cellular osmotic balance and enhancing physiological processes such as protein synthesis has made it an effective dietary supplement for enhancing fish growth. Recent studies indicate that this compound not only supports growth performance but also plays a fundamental role in enhancing fish immunity. Betaine enhances the innate defense mechanisms of fish against pathogens by increasing the activity of immune cells, especially macrophages, regulating cytokine production, and reducing inflammation. In addition, betaine’s antioxidant properties reduce oxidative stress and improve immune signaling, helping fish maintain optimal immune function even in stressful environments. This comprehensive review aims to investigate the multifaceted role of betaine in improving fish immunity and antioxidant responses and the mechanisms associated with these roles.

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.