Aquaculture Nutrition最新文献

The molecular mechanisms underlying species-specific lipid distribution patterns in teleosts remain poorly understood. This study investigated two marine carnivorous species with distinct fat deposition characteristics: the golden pompano (Trachinotus ovatus), which stores lipid in the liver and muscle, and the spotted sea bass (Lateolabrax maculatus), which primarily stores fat in the abdominal adipose tissue. Juveniles (~10.0 g) were fed three iso-nitrogenous diets (45% protein) with graded lipid levels (12%, 14%, and 16%) for 8 weeks. Two-way analysis of variance (ANOVA) analyses revealed significant species × diet interactions affecting lipid distribution (p < 0.05). Golden pompano exhibited higher hepatic/muscular crude lipid and triglyceride (TG) levels than spotted sea bass, whereas abdominal TG content and abdominal fat index (AFI) were lower (p < 0.05). Transcriptomics and qPCR revealed tissue-specific regulatory mechanisms: there was an upregulation of hepatic and muscular fatty acid transport genes (ldlr and fabp), synthesis (g6pd), and deposition (dgat1) with increasing dietary lipid in golden pompano. Additionally, enhanced adipogenesis (c/ebpα and pparγ) and TG storage (dgat1) were observed in the abdominal adipose of spotted sea bass. These findings indicate that lipid accumulation in the liver and muscle of golden pompano is driven by increased fatty acid transport and lipogenesis, while spotted sea bass prioritizes abdominal adipogenesis. This study provides novel insights into the regulation of lipid metabolism in teleosts, with implications for aquaculture feed optimization.

Mugwort leaf powder (MLP), as a typical Chinese herbal medicine containing lots of flavonoids and polysaccharides, has strong anti-inflammatory and immune effects. However, there are relatively few studies on the use of MLP in aquatic animals fed high-fat (HF) diets (HFDs), especially in terms of lipid metabolism and intestinal health. To investigate the impacts of MLP on the growth performance and health status of common carp fed HFDs, common carp were provided with a basal diet, an HFD, and the HFDs enriched with 0.6%, 1.2%, 1.8%, and 2.4% MLP for 8 weeks. Dietary supplementation with 0.6%−1.2% MLP enhanced fish growth and feed utilization compared to the HF group (p < 0.05). Supplementation with over 1.2% MLP increased villus height and digestive enzyme activities (p < 0.05). Supplementation with 1.2% MLP upregulated intestinal anti-inflammatory gene expression and decreased serum triglyceride levels (p < 0.05). Moreover, MLP significantly mitigated the degree of hepatocyte vacuolation and reduced adipocyte size (p < 0.05). Supplementation with over 1.2% MLP decreased the crude lipid, triglyceride, and cholesterol levels in the hepatopancreas, as well as downregulated the lipid synthesis gene expression of fas and upregulated the lipolysis gene expression of cpt1 in the hepatopancreas (p < 0.05). The gene expression related to lipid synthesis in adipose tissue also exhibited a downregulated tendency (p < 0.05). Combining the quadratic regression results of the above indices, this study concluded that supplementation with 0.92%−2.17% MLP positively influenced the growth, intestinal well-being, and lipid metabolism of common carp fed HFDs.

While aquaculture often relies on excessive lipid intake to bolster fish growth and cut feed expenses, this practice can also result in hepatic fat accumulation, inflammatory responses, oxidative damage, and immune system malfunctions in aquatic creatures. Astaxanthin (AST), a potent antioxidant, holds promise in mitigating these detrimental effects associated with high-lipid (HL) diets. The objective of this study was to investigate the functional contributions and the fundamental molecular pathways of both synthetically produced and algae-derived Ast, focusing on their impacts on growth rates, lipid regulation, and hepatic well-being in juvenile Trachinotus ovatus maintained on diets rich in lipids. The experimental setup involved feeding T. ovatus for 8 weeks with four different diets: a control feed (CF) with normal lipid content, a HL diet, a HL diet supplemented with synthetic AST (HL + S), and a HL diet supplemented with algal-derived AST (HL + A). When compared to the HL diet, the inclusion of Ast from both sources in the feed significantly improved the growth performance and survival rate (SR) of T. ovatus. Furthermore, both forms of Ast significantly increased glutathione reductase (GR)activity and high-density lipoprotein (HDL) levels, while also decreasing the levels of lipid transport-related substances in the serum. They were also successful in mitigating hepatic lipid overload. Regarding antioxidant potential, the addition of Ast notably potentiated the Nrf2/Keap-1 signaling cascades and boosted the functionality of antioxidant enzymes. Furthermore, Ast from both synthetic and algae origins augmented the innate immune defenses of T. ovatus, leading to a decreased sensitivity to stress in the fish. To conclude, incorporating Ast from either source into the high-fat diet of T. ovatus mitigated the detrimental consequences of such a diet, including impeded growth, weakened antioxidant defenses, and weakened innate immune responses. Moreover, both sources of Ast exhibited beneficial effects on sustaining lipid metabolism homeostasis and enhancing hepatic well-being in the fish.

The incorporation of edible insects into fish diets has gained increasing attention due to their rich nutritional profile and potential as alternative ingredients in aquafeeds. This review examines the composition of key insect species, including Hermetia illucens, Tenebrio molitor, Musca domestica, Zophobas morio, and Bombyx mori, comparing their macronutrient and micronutrient profiles, as well as their applicability in dietary formulations for fish. Studies indicate that these insect meals can effectively replace fishmeal (FM) in varying proportions without compromising growth performance, nutrient digestibility, immunological response, or feed efficiency in both freshwater and marine species. Furthermore, their amino acid and fatty acid profiles closely align with the nutritional needs of farmed fish, supporting optimal health and development.

The current trial sought to assess the impact of fermented chicory root waste (FCRW) dietary administration on growth, lipid metabolism, chemical composition, and intestinal barrier pathway in common carp (Cyprinus carpio L.). Firstly, a single-factor experiment followed by an orthogonal test indicated the optimum factors, such as 30°C for 36 h, a 10% inoculation amount, and a 65% solid–liquid ratio for producing FCRW containing a 12.24% protein. A total of 180 common carp, with an average initial weight of 26.99 ± 4.04 g, were randomly allocated into 12 tanks, with each tank housing 15 individuals. The initial group functioned as the control group (CG) and was provided with a basal diet; meanwhile, the remaining three groups were fed high-fat (HF) diets supplemented with various levels of FCRW, 0%, 5%, and 15% for HF, HF-L, and HF-H, respectively. The feeding trial was prolonged to 56 days. The results of the feeding trial demonstrated that the fish group receiving an HF diet supplemented with a greater proportion of FCRW (15%) exhibited superior growth and feed efficiency. Both 5% and 15% FCRW significantly reduced VSI and HSI, while 15% FCRW increased whole-body crude protein and decreased body/liver lipids. FCRW supplementation also lowered serum/liver triglycerides and serum LDL-C. Additionally, all FCRW levels enhanced antioxidant markers (MDA, AKP, CAT, superoxide dismutase [SOD]) and innate immunity (LZM). Histology showed reduced hepatocyte vacuolation and lipid droplets. Crucially, 15% FCRW upregulated lipolysis genes (lpl, hsl, ppar-α) and downregulated lipogenesis genes (acc-α, fas, ppar-γ). Regarding intestinal structural integrity, FCRW improved intestinal morphology and upregulated barrier genes (occludin, claudin-3, zo-1). It suppressed proinflammatory cytokines (il-1β, il-6) and activated anti-inflammatory pathways (il-10, tgf-β, tlr4, nf-κb). Gut microbiota analysis revealed increased beneficial bacteria (e.g., Firmicutes).

Concerns regarding food-borne interventions in crayfish have been raised due to excessive farming densities and the overuse of drugs in aquaculture. This research focused on examining the dose–response relationship of Laminaria japonica extract supplementation on growth performance, hepatopancreas antioxidant status, and innate immune function in crayfish, while exploring the microbiota-mediated metabolic pathways involved. A total of 750 juvenile crayfish (4.00 g) were randomly assigned to five treatments and fed diets supplemented with L. japonica extract at concentrations of 0, 500, 1000, 1500, and 2000 mg/kg for 42 days. The results demonstrated that dietary L. japonica extract improved the growth and hepatic health status, as indicated by well-structured hepatic tubules and increased fibroblast cells, as well as lower hemolymph glutamic oxaloacetic transaminase (GOT) level (p < 0.05). Dietary supplementation with 1500 mg/kg L. japonica extracts significantly increased hemolymph lysozyme (LZM) and acid phosphatase (ACP) activities (p < 0.05). Additionally, L. japonica extract supplementation considerably increased hepatopancreas glutathione (GSH) content and activities of catalase (CAT), superoxide dismutase (SOD), and GSH reductase (GR) (p < 0.05). Furthermore, dietary L. japonica extract alleviated microbial dysbiosis, as characterized by the observed decrease in opportunistic pathogens Citrobacter and Vibrio and an increase in beneficial taxa Tyzzerella. Further findings found that 349 differential microbes were identified, with Bacillus, Chryseobacterium, and Prevotella playing key roles. In summary, the optimal dietary inclusion level of L. japonica extract was recommended to be 1507.89–1614.26 mg/kg. Dietary supplementation with 1500 mg/kg of L. japonica extract improved the immunity and antioxidant capacities of crayfish by reshaping microbial co-occurrence networks.

Generally, the inadequate feeding of aquatic organisms can mitigate stress and disease vulnerability. In contrast, overfeeding has worsened the water quality in addition to the high feeding cost. Hence, the present study was performed to evaluate two feeding regimes (alternate-day feeding [ADF] and daily feeding [DF]), plus dietary supplementation with Melissa officinalis (lemon balm leaves [LBL]) on growth, body composition, digestion, and hemato-physiological status of hybrid red tilapia (Oreochromis spp.). Fish (n = 180) with an average weight of 18.14 ± 0.48 g were distributed into six groups (30 fish/group; 3 replicates/group; 10 fish/replicate) in a 2 × 3 factorial feeding trial for 60 days. The groups were ADF + LBL0, ADF + LBL1, ADF + LBL2, DF + LBL0, DF + LBL1, and DF + LBL2. The LBL was added to the basal diet at the doses of 0%, 1%, and 2% (LBL0, LBL1, and LBL2), respectively. The outcomes revealed that ADF achieved the best feed conversion ratio (FCR) (1.68), but the growth did not show substantial variation between ADF and DF. The LBL1 supplementation enhanced final body weight (FBW) (33.16 g), total weight gain (TWG) (14.20 g/fish), and specific growth rate (SGR) (0.93 %/day). The interaction between LBL and feeding strategies showed that the ADF + LBL1 had the best FCR (1.31). Crude lipid and ash content substantially changed (p < 0.05) by feeding regimes and LBL addition. The DF + LBL0 group had the highest lipid (32.08%) and the lowest ash content (18.28%). Dietary LBL2 significantly increased (p < 0.05) hemoglobin (Hb) (8.30 g/dL), hematocrit (Hct) (26.25%), and white blood cell (WBC) count (419.44 × 10³/mm³). Moreover, the ADF regime significantly decreased (p < 0.05) glucose level (47.83 ng/L); meanwhile, the DF regime notably increased amylase activity (47.66 U/g protein). Our conclusion suggested that feeding hybrid red tilapia with an ADF schedule with a diet enriched with LBL can improve growth, feed utilization, and physiological response. This offers an avenue to assist the aquaculture sector and lower feed expenses.

The present research examined the impact of sodium humate (SH) in feed on the intestinal health of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). GIFT with average weight of 3.9 g were provided with diets incorporated diverse content of SH from low to high (0%, 0.1%, 0.2%, 0.4%, and 0.6%, denoted as SH0, SH1, SH2, SH4, and SH6) for 63 days. Results indicated that incorporating 0.4%–0.6% SH into the diet significantly reduced the plasma lactulose/rhamnose ratio, while plasma diamine oxidase (DAO) activity was depressed by supplementation with 0.1%–0.4% SH (p < 0.05). Dietary SH level increased the length and width of villu, as well as the levels of polymeric immunoglobulin receptor in the distal intestine (DI). The SH2 group exhibited elevated levels of interleukin (IL)-10 in the DI and transforming growth factor β1 (TGF-β1) and IL-1β in the proximal intestine (PI). On the other hand, the contents of tumor necrosis factor-α (TNF-α) in the middle intestine (MI), IL-1β, and IL-6 in the MI and the PI were generally lower in the SH groups contrast to the SH0 group, while interferon-gamma (IFN-γ) and IL-8 levels in the DI showed the opposite trend. Additionally, dietary inclusion of 0.2% SH promoted the intestinal microbiota species diversity and relative abundance of Cetobacterium, with SH6 group displaying the highest complexity. Overall, dietary SH supplementation improved intestinal health of GIFT by decreasing mucosal permeability, improving intestinal absorption surface area, enhancing intestinal immune barrier, and reduce inflammation. The recommended level of SH was 0.2%–0.4% of diet for GIFT.

Tryptophan, recognized as the third limiting amino acid, plays a crucial physiological function. The optimal tryptophan requirement for oriental river prawn (Macrobrachium nipponense) was assessed, and its impact on agonistic behavior was evaluated in this study. An 8-week feeding trial was implemented with six different tryptophan levels: 0.07%, 0.17%, 0.29%, 0.39%, 0.52%, and 0.64%. The results showed that the highest specific growth rate (SGR) was observed in prawns fed with 0.29% tryptophan. Furthermore, body protein deposition (BPD) and protein efficiency ratio (PER) were significantly elevated in the 0.39% tryptophan group than those in the 0.07% tryptophan group, while the feed conversion rate (FCR) was lowest in the 0.39% tryptophan group. Based on quadratic regression analysis of SGR, BPD, FCR, and PER, the optimal tryptophan requirement was determined to be 0.35%–0.39% of dry matter, 0.90%–1.01% of crude protein. In the 0.52% tryptophan group, crude protein and lipid contents were improved, while ash content was the lowest. The total protein (TP), cholesterol, and urea nitrogen (UN) contents in the hemolymph were observed to be the highest levels in the 0.64% tryptophan group, although there was a reduction in triglyceride (TG) and glucose (GLU) levels. Muscle tor gene expression was the highest at 0.39% tryptophan, with atf4 and atf3 expressions suppressed. Hepatopancreas tor and cpt1 gene mRNA peaked at 0.29% tryptophan, while acc, fas, and atf4 genes were inhibited. Following the feeding trial, prawns fed diets with 0.07%, 0.29%, and 0.64% tryptophan were randomly selected for the detection of agonistic behaviors. Prawns fed 0.29% and 0.64% tryptophan showed less aggression than those fed 0.07%. Serotonin levels were highest in the 0.64% group, followed by 0.29%, and lowest in 0.07%. The 5-ht1b gene expression was significantly increased in the 0.64% tryptophan group compared to the 0.29% and 0.07% tryptophan groups. Both serotonin levels and 5-ht1b expression showed the same significant difference before and after fighting behavior, with increases observed postfight across all treatments. In conclusion, the optimal dietary tryptophan requirement for the oriental river prawn was estimated to be between 0.35% and 0.39% of dry matter (0.90% and 1.01% of crude protein), which enhanced growth performance and effectively reduced agonistic behavior.

Fish skin provides vital protection against environmental stressors and pathogens, whose health is significantly affected by dietary components. In intensive aquaculture, accumulated ammonia seriously affected fish skin structure and immune responses. In this study, largemouth bass were fed with control diet (Con), high-carbohydrate (HC) diet and HC diet supplemented with betaine (HC + Bet) for 8 weeks before ammonia exposure. The skin structure, immune responses, programmed cell death (PCD), and status of mitogen-activated protein kinase (MAPK) pathways were evaluated. Results indicated ammonia stress increased epidermal thickness and skin mucus cell numbers, while betaine supplementation recovered the HC-restricted epidermal thickness at 7 days post-stress. Ammonia stress also induced the expression of inflammatory cytokines in skin, while betaine significantly inhibited NF-κB/myd88 pathway to alleviate the over-inflammation in skin of HC-fed largemouth bass. Further study identified the significantly increased TdT-mediated dUTP Nick-End Labeling⁺ (TUNEL⁺) cell numbers in bass skin after ammonia stress, which resulted from apoptosis rather than pyroptosis. Furthermore, p38 MAPK and c-Jun N-terminal kinase (JNK) signaling pathways mediated for the ammonia-induced apoptosis, while dietary betaine supplementation inhibited the over-activation of p38 MAPK and JNK pathways to reduce epidermal apoptosis during ammonia stress. Therefore, dietary betaine alleviated both over-inflammation and apoptosis in the skin of largemouth bass fed with HC diet during ammonia stress.