Aquaculture Nutrition最新文献

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.

Larimichthys crocea (L. crocea), an important species in mariculture, is highly valued for its nutritional benefits, delicate flavor, and distinctive golden body, making it a popular choice among consumers. However, suboptimal breeding conditions and high stocking densities, often lead to reduced flesh texture and a deterioration in body color. Given the significant role body color plays in determining the commercial value of this species, this study evaluated the impact of various dietary supplements on color enhancement. One basal diet and three separate experimental diets were formulated: one supplemented with 200 mg/kg Tagetes erecta extract (2% lutein), one with 200 mg/kg astaxanthin (2%), and one with 200 mg/kg amaranth (Amaranthus spp.) leaf extract (85%). The results indicated that T. erecta was more effective in enhancing the body color of L. crocea than the other two supplements after 28 days of feeding, with the a^∗ value (red–green) 1.25-fold higher than the control group and ventral b^∗ value (yellow–blue) was significantly elevated (p = 0.028) compared to the control group. Initial mechanistic studies revealed that T. erecta enhanced body color through regulating carotenoid uptake and melanogenesis. These findings provide valuable insights for optimizing feeding strategies to improve the market appeal and commercial value of L. crocea in mariculture.

Use of corn-fermented protein (CFP), a new product produced using Fluid Quip Technologies, as a protein source in aquaculture feeds, constitutes a promising option due to its dependable supply and cost-effectiveness. In this study, two growth trials were performed to evaluate the effectiveness of CFP products such as CFPA (48% crude protein [CP]), CFPB1 (50% CP), and CFPB2 (60% CP) from two different sources (A and B) in practical diets for juvenile Pacific white shrimp (Litopenaeus vannamei). The test diets in both trials were formulated to be isonitrogenous and isolipidic (36% crude protein and 6% crude lipid). These diets were produced by supplementing the basal diet with 5%, 10%, 15%, and 20% CFPA or 4%, 8%, 12%, and 16% of CFPB1 and CFPB2 to replace soybean meal (SBM) on an isonitrogenous basis. In a 6-week experiment, shrimp (1.02 ± 0.02 g mean weight, 15 shrimp per tank, n = 6) were offered CFPA diets. Growth parameters and protein retention showed no significant differences among diets. However, a significant feed conversion ratio (FCR) increase was observed when shrimp were fed a diet containing 20% CFPA compared to the basal and 5% CFPA diets. Physiological gene expression analysis revealed no signs of gut inflammation or shifts in hepatopancreas digestive enzymes (p  > 0.05). However, the expression of immune-related tnf-α gene was significantly upregulated (p  < 0.05) in shrimp-fed CFPA 25% diet compared to CFPA 5% and control groups. In a 7-week experiment, shrimp (0.55 ± 0.01 g, 15 shrimp per tank, n = 5) received experimental CFPB1 or CFPB2 diets. No differences were observed in growth performance. This research highlights the potential of CFP as a protein source in shrimp diets by expanding the range of feed ingredients and identifying optimal inclusion levels.

This study evaluates the potential of microalgae, Chlorella vulgaris, and black soldier fly larvae (BSFL), Hermetia illucens, as an alternative complete diet for red hybrid tilapia, addressing challenges arising from declining fish stocks and unsustainable aquaculture practices reliant on fish meal in commercial pellets. The study involved 270 tilapia separated into three groups: Group 1 received C. vulgaris alone, Group 2 was fed with a combination of BSFL and C. vulgaris, and Group 3 with commercial pellets (control) for 70 days. The results demonstrated that the combination of BSFL and C. vulgaris had a high potential to be an alternative to commercial pellets, with comparable growth performance with the control group. In contrast, fish-fed with C. vulgaris alone exhibited significantly slower growth rates and higher mortality. Economic analysis showed that the BSFL and C. vulgaris combination reduced feed costs by 59.40% and increased the profit index by 144.79% compared to the control group. However, the combination diet did not provide significant protection against streptococcosis compared to commercial pellets. This study highlights the potential of incorporating BSFL and C. vulgaris into tilapia diets to enhance sustainability and economic outcomes for farmers. It also emphasizes the role of alternative feeds in promoting environmentally sustainable aquaculture practices, with the goal of achieving zero-carbon emissions. This study is the earliest report on the direct combination of BSFL and C. vulgaris diet in tilapia, a globally cultivated aquaculture fish species.

This study evaluated the effects of dietary synthetic astaxanthin (SA), Haematococcus pluvialis (HP) and Phaffia rhodozyma (PR) on the growth performance, antioxidant activity, innate immunity, morphology, and pigmentation of juvenile Litopenaeus vannamei. Shrimp (1.15 ± 0.01 g) were fed with the control diet and astaxanthin diets containing 20 mg/kg of astaxanthin from three sources (SA, HP, and PR) for 56 days. The results indicated that, compared with the control group, growth performance was observably elevated in the HP and PR groups (p < 0.05). The astaxanthin (SA, HP, and PR) supplemented diets markedly elevated the activities of glutathione peroxidase (GPx) and GST in the intestine and hepatopancreas (p < 0.05), while observably reduced the MDA content (p < 0.05). The apoptosis rates in three astaxanthin groups were noticeably reduced in comparison with the control group (p < 0.05). Dietary astaxanthin (SA, HP, and PR) observably elevated the expression of the Toll, IMD, and CAT genes in the hepatopancreas (p < 0.05). Besides, dietary astaxanthin (SA, HP, and PR) noticeably improved the astaxanthin accumulation and pigmentation of shrimp (p < 0.05). The survival rates of shrimp challenged with Aeromonas hydrophila were markedly higher in the astaxanthin groups than in the control group (p < 0.05), and no significant difference was detected among three astaxanthin groups (p > 0.05). Moreover, our results suggested that natural astaxanthin (HP and PR) was more effective for enhancing growth and antioxidant capacity of shrimp. Nevertheless, no marked difference was detected between natural astaxanthin and SA in coloration performance and disease resistance.