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Image anomaly detection is a trending research topic in computer vision. The objective is to build models using available normal samples to detect various abnormal images without depending on real abnormal samples. It has high research significance and value for applications in the detection of defects in product appearance, medical image analysis, hyperspectral image processing, and other fields. This paper proposes an image anomaly detection algorithm based on feature distillation and an autoencoder structure, which uses the feature distillation structure of a dual-teacher network to train the encoder, thus suppressing the reconstruction of abnormal regions. This system also introduces an attention mechanism to highlight the detection objects, achieving effective detection of different defects in product appearance. In addition, this paper proposes a method for anomaly evaluation based on patch similarity that calculates the difference between the reconstructed image and the input image according to different regions of the image, thus improving the sensitivity and accuracy of the anomaly score. This paper conducts experiments on several datasets, and the results show that the proposed algorithm has superior performance in image anomaly detection. It achieves 98.8% average AUC on the SMDC-DET dataset and 98.9% average AUC on the MVTec-AD dataset. [ABSTRACT FROM AUTHOR]

This study investigated the time-optimal low-thrust interplanetary transfer problem, and proposes a fast estimation method for guessing the initial costate and optimal transfer time based on a surrogate model, and applied it to the problem of the 11th Global Trajectory Optimization Competition (GTOC 11). Two core methods are proposed in this paper: (1) a fast generation method called the neighbor point iteration algorithm (NPIA) is presented for rapidly generating low-thrust databases with high efficiency and accuracy; and (2) deep neural networks (DNNs) are adopted to learn the state–costate pairs of low-thrust databases, and the surrogate network can quickly estimate the initial costate and optimal transfer time of the low-thrust interplanetary problem. Experiments verified the proposed method and investigated the influence of network structure, learning rate, and loss function on the accuracy of network estimation. The effects of database generation and network estimation were compared based on three transfer scenarios: coplanar, non-coplanar, and arbitrary orbital transfer. In addition, the application case study showed that the proposed method can quickly obtain the time-optimal low-thrust solution to GTOC 11's interplanetary transfer, which achieves high precision and meets the terminal constraints. [ABSTRACT FROM AUTHOR]

In the integrated circuit (IC) packaging, the surface defect detection of flexible printed circuit boards (FPCBs) is important to control the quality of IC. Although various computer vision (CV)-based object detection frameworks have been widely used in industrial surface defect detection scenarios, FPCB surface defect detection is still challenging due to non-salient defects and the similarities between diverse defects on FPCBs. To solve this problem, a decoupled two-stage object detection framework based on convolutional neural networks (CNNs) is proposed, wherein the localization task and the classification task are decoupled through two specific modules. Specifically, to effectively locate non-salient defects, a multi-hierarchical aggregation (MHA) block is proposed as a location feature (LF) enhancement module in the defect localization task. Meanwhile, to accurately classify similar defects, a locally non-local (LNL) block is presented as a SEF enhancement module in the defect classification task. What is more, an FPCB surface defect detection dataset (FPCB-DET) is built with corresponding defect category and defect location annotations. Evaluated on the FPCB-DET, the proposed framework achieves state-of-the-art (SOTA) accuracy to 94.15% mean average precision (mAP) compared with the existing surface defect detection networks. Soon, source code and dataset will be available at https://github.com/SCUTyzy/decoupled-two-stage-framework. [ABSTRACT FROM AUTHOR]

In advanced integrated circuit packing, a very important substrate is high-density flexible printed circuit (FPC) board, which is small and foldable. The detection of the circular holes on FPCs’ surfaces through machine vision is very useful to identify root causes in FPC manufacturing process. However, it is a challenge as FPC images always contain many high details. This paper proposes a circle detection method with a modified tri-class thresholding-based contour extraction to detect and measure the circular holes on FPCs’ surfaces. It first extracts object contours by using a modified tri-class thresholding and then uses two circle validation criterions to eliminate noncircles: one is based on geometrical features and the other is based on the Helmholtz principle. Moreover, an iterative circle parameter refinement strategy is proposed. Experiments are carried out on 120 FPC images and the results indicate that the modified tri-class thresholding-based contour extraction method is more efficient than Canny detector, and the proposed circle detection method shows a better performance in terms of false detection rate, computation cost, and robustness than three other popular algorithms for detecting the circles in FPC images. [ABSTRACT FROM AUTHOR]

This paper is mainly devoted to a monotonically convergent iterative learning control (ILC) design for a class of uncertain discrete-time switched systems with state delay (UDTSDSs). By taking advantage of output error and state information, a hybrid ILC law for a class of UDTSDSs is proposed. After the ILC process is transformed into a 2D system, sufficient conditions in terms of linear matrix inequalities (LMIs) are derived by using a multiple Lyapunov–Krasovskii-like functional approach and a quadratic performance function. It is shown that if certain LMIs are met, the tracking error 2-norm converges monotonically to zero along the iteration direction, while the learning gains could be determined directly by solving the LMIs. The simulation results are provided to illustrate the theoretical analysis. [ABSTRACT FROM AUTHOR]

This study investigated the influences of dietary zinc (Zn) on lipid and fatty acid metabolism of Scylla paramamosain. Three diets containing analyzed Zn levels including 44.5 (low Zn), 68.5 (medium Zn) and 254.7 (high Zn) mg/kg were prepared and fed to mud crab for 10 weeks, respectively. Medium dietary Zn levels improved the growth of mud crab than those fed the high Zn diet. The concentration of Zn in tissues was positively correlated with dietary Zn levels. Crabs fed with high Zn diet significantly decreased lipid content in hepatopancreas and muscle when compared to those fed the medium Zn diet. The lowest diameter, area and number of R cell in hepatopancreas histology were observed in those fed the high Zn diet. Furthermore, medium levels of dietary Zn significantly increased docosahexaenoic acid (DHA) and n-3 polyunsaturated fatty acid (PUFA) contents in hepatopancreas. Crabs fed high Zn diet dramatically down-regulated expression of acc , fas , g6pd , 6pgd and srebp , but up-regulated expression of aco3 , cpt1 and fabp1 in hepatopancreas. Crabs fed with medium Zn diet significantly increased the mRNA levels of fad in hepatopancreas. In summary, the results of present study emphasized the adverse effects of excess dietary Zn (254.7 mg/kg) on suppress hepatopancreatic lipid and n-3 PUFA accumulation, dietary 68.5 mg/kg Zn level was recommended to maintain optimal lipid and fatty acid metabolism of mud crab. • High levels dietary Zn caused lipid depletion in hepatopancreas and muscle of mud crab. • High levels dietary Zn restrained lipogenesis and promoted lipolysis of hepatopancreas. • Medium levels dietary Zn increased hepatopancreatic DHA and n-3 PUFA accumulation. [ABSTRACT FROM AUTHOR]

• Low salinity is new used in mud crab culture to expand the inland saline aquaculture. • Dietary lipid source, but not salinity, influenced nutritional values of flesh of mud crab. • Low salinity changed the myofiber structure and provided new texture for consumers. • Low salinity and dietary soybean oil weakened the umami taste and aroma of crab flesh. The quality of crustaceans' flesh has direct impact on consumers' purchase choices, with water environment and dietary nutrition being effective ways to regulate flesh quality. The aim of present study was to investigate the impacts of water salinity (low, 4 and medium, 23) and dietary lipid source (fish oil and soybean oil) on nutritional values, texture, taste and odor of flesh of mud crab. While water salinity had no significant influence on nutritional values of crab flesh, crabs fed soybean oil displayed significantly lower contents of amino acids and n-3 PUFAs in muscle. However, crabs reared at low salinity showed reduced flesh hardness, chewiness and gumminess likely related to altered myofiber structure, that impacted muscle texture. Furthermore, low salinity and dietary soybean oil weakened umami taste and aroma characteristics of crab flesh associated with decreased contents of free amino acids, flavor nucleotides, inorganic ions and odor active compounds in flesh. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the effects of dietary choline levels on growth performance, antioxidant capacity, innate immunity and hemocyte apoptosis of Litopenaeus vannamei. Six isonitrogenous and isolipidic diets were formulated to contain different choline levels: 2.91 (basal diet), 3.85, 4.67, 6.55, 10.70 and 18.90 g kg−1choline, respectively. The results indicated that shrimp fed diet with 4.67 g kg−1 choline had the highest final body weight (FBW), percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), and activities of alkaline phosphatase (AKP) and phenoloxidase (PO) in hemolymph among all treatments. Shrimp fed diet with 18.90 g kg−1 choline exhibited significantly lower crude lipid in hepatopancreas than those fed diets with 2.91, 3.85, 4.67 and 6.55 g kg−1 choline (P < 0.05). The concentration of reactive oxygen species (ROS) and apoptosis rate in hemocytes significantly decreased with the increase of dietary choline levels (P < 0.05). Shrimp fed diets with 6.55, 10.70 and 18.90 g kg−1 choline had significantly higher scavenging ability of hydroxyl radical (SAHR) and total antioxidant capacity (T-AOC) in hemolymph than those fed diet with 2.91 g kg−1 choline (P < 0.05). Dietary choline supplementation down-regulated the expression of genes related to apoptosis such as caspase-1 , caspase-3 , caspase-8 , p53 , and p38MAPK in hemocytes (P < 0.05), while up-regulated the expression of anti-apoptosis gene bcl2 in hemocytes (P < 0.05). Overall, the results of the present study demonstrated that appropriate dietary choline could improve growth performance and feed utilization, enhance antioxidant capacity and innate immunity, and mitigate apoptosis in Litopenaeus vannamei. Moreover, the inhibition of hemocyte apoptosis by dietary choline may be regulated by the p38MAPK-p53 signaling pathway. A plausible mechanism for how choline affects growth performance, antioxidant capacity, and innate immunity, and inhibits hemocyte apoptosis in Litopenaeus vannamei. Solid red arrows indicate promotion and black lines indicate suppression. [Display omitted] • The optimal choline requirement was estimated to be 3.27 g kg−1 for juvenile Litopenaeus vannamei. • Dietary choline could enhance antioxidant effects by a series of enzymatic reactions. • Dietary excessive choline could significantly reduce ROS concentration and apoptotic rate in hemocytes. • Inhibitory effect of dietary choline on hemocyte apoptosis may be regulated by p38MAPK-p53 signaling pathway. [ABSTRACT FROM AUTHOR]

• Surface residual stress is measured by XRD using symmetrical inclining method. • A novel optimization strategy is proposed to minimize surface residual stress. • Effects of turning parameters on surface residual stress are investigated. • The improved PSO algorithm shows a better performance in convergence efficiency. • Model for process parameter optimization is validated by the experimental results. Surface residual stress, induced by process parameters, has a significant effect on the performance of workpiece. Focusing on the minimization of surface residual stress in turning DT4E pure iron, the influence of cutting speed (v c , 80–240 m/min), feed rate (f , 0.04–0.20 mm/rev) and depth of cut (a p , 0.05–0.25 mm) on surface tensile residual stress (σ τ in cutting direction, σ r in feeding direction) is analyzed, and the optimal combination of process parameters is found. Central composite design (CCD) method is first used to design the turning experiments of pure iron material. By means of range analysis and the main effect plot, the relations between the process parameters and responses are discussed in detail. Subsequently, the non-linear mapping models of σ τ and σ r with regard to turning parameters are established respectively using support vector regression (SVR) method. The experimental database is utilized to validate the effectiveness of SVR models. Taking the total stress σ as the optimization objective of process parameters, the optimal combination of turning parameters within given parameter ranges is finally obtained by combining SVR models with improved particle swarm optimization (PSO) algorithm. Further, the comparisons between genetic algorithm (GA), traditional and improved PSO algorithms are conducted, which indicate that the improved PSO algorithm has an advantage in convergence efficiency. Finally, verification experiments are performed to confirm the minimization of surface residual stress. The results show that the proposed optimization strategy of process parameters is effective and reliable, while at the same time providing a good prediction accuracy. [ABSTRACT FROM AUTHOR]

In the structural fatigue fields, such as aerospace, maritime, and civil engineering, the accurate construction of the Probability-Stress-Life (P-S-N) curve is crucial for preventing unexpected structural failures and is fundamental to the engineering design process. Conventional methods usually assume that the fatigue life distribution follows a normal or weibull distribution, which overlooks the differences of life distribution at different stress levels and introduces subjective errors. To address this issue, this paper proposes a new approach based a multi-layer perceptron model with maximum entropy algorithm (MPME) for probabilistic fatigue life prediction. During the derivation of life probability distribution function in this approach, the type not require any pre-assumption, thus effectively avoiding the introduction of subjective errors. Specifically, the dispersed information of fatigue life is quantified as various life distribution statistical features such as mean, variance, skewness, and kurtosis. Next, learn the continuous functional relationship between stress and these features using a multi-layer perceptron (MLP). Finally, the target probability distribution is derived using the maximum entropy algorithm, with the predicted distribution features obtained from the MLP serving as constraints for it. In addition, to ensure the consistency between the prediction of MLP and physical laws, we encode physical knowledge into the network loss to guide the updating of network parameters. Experimental results of two different material fatigue data demonstrate that, compared to traditional deterministic model-based methods and machine learning methods, the MPME in this paper can more accurately predict the probabilistic fatigue life. • A multi-layer perceptron with maximum entropy algorithm for probabilistic fatigue life prediction is proposed. • The paradigm of learning distribution models parameter in machine learning-based methods had been revolutionized. • A hybrid Loss function is constructed to guide the parameter updating of network. • The performance of the model was evaluated using three metrics on two datasets. [ABSTRACT FROM AUTHOR]

• The dynamic data representation method is applied to semi-supervised fault classification and the differences between it with supervised fault detection are emphasized. • A semi-supervised form of CNN, i.e., SS-LGF-CLN, is proposed for fault classification, which can jointly capture latent manifold features of unlabeled samples and extract discriminative features of labeled samples. • The usefulness of global inter-variable correction features in representing incipient faults is discussed for the first time, while other CNN based fault classification methods focused on local inter-variable correction features. • An overall fault classification accuracy of 91.29% including incipient faults is achieved on the benchmark process. Effective fault classification is of great significance to isolate and eliminate faults in the smart manufacturing process, especially for chemical industry. However, incipient faults and limited labeled samples make it hard to classify faults accurately. This motivates the formulation of a semi-supervised convolutional ladder network with local and global feature fusion. In the algorithm, a convolutional ladder network is developed to capture higher-order correlations from both labeled and unlabeled samples simultaneously to overcome the problem caused by limited labeled samples, skipped connections are embedded within which to make a balance between supervised and unsupervised feature learning for further identifying faults. To improve the classification performance on incipient faults, a local and global feature fusion strategy is proposed to enhance the representation of incipient faults. Furthermore, a semi-supervised dynamic data representation strategy is introduced to jointly deal with labeled and unlabeled process samples, which enables the proposed method to handle process dynamics by characterizing temporal information of process variables. Experiments on the Tennessee Eastman process show that the proposed method is effective for process fault classification when labeled samples are limited compared to the state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

• Excessive dietary copper led to coloration abnormalities in mud crab. • Main tissues of copper bioaccumulation are the carapace and hepatopancreas, not the muscle. • Dietary copper supplementation influenced oxidation resistance. • Dietary copper regulated the metabolism of copper-containing proteins. • Excessive dietary copper in mud crab could be a potential ecological and human health risk. Copper is a widespread pollutant in marine environments, and marine animals can ingest large amounts of copper through the food chain. Here, an 8-week feeding trial was designed to investigate the effects of different dietary copper levels on coloration, copper bioaccumulation, stress response and oxidation resistance of juvenile mud crab Scylla paramamosain. The results indicated that crabs fed the diet with 162 mg/kg copper exhibited a dark-blue carapace and hemolymph. The accumulation of copper in tissues was positively correlated with the level of copper in feed. High/excess dietary copper (162 mg/kg) up-regulated the expression of stress response related genes, and reduced the expression/activities of anti-oxidation genes/enzymes. The activity of phenoloxidase decreased significantly when dietary copper level was 86−162 mg/kg, and the expression of hemocyanin was up-regulated in crab fed the diets with 28−162 mg/kg copper. Overall, the results of the present study indicated that high dietary copper led to parachrea in carapace and hemolymph of mud crab, and caused copper deposition abnormality in carapace and hepatopancreas. The data suggested that the toxic effects of dietary copper were concentration-dependent such that, excess dietary copper (162 mg/kg) had adverse impacts on oxidation resistance. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to investigate the effects of different dietary dosage forms of zinc on growth performance, meat quality, antioxidant and immune capacity of juvenile Pacific white shrimp, Litopenaeus vannamei. Four isonitrogenous and isolipidic diets were formulated to contain different dosage forms of zinc, the control diet (no-supplemented zinc), I-Zn diet (120 mg kg−1 zinc from zinc sulfate), M-Zn diet (60/60 mg kg−1, zinc sulfate/zinc amino acid complex = 1:1) and Availa-Zn diet (60 mg kg−1 zinc from zinc amino acid complex), respectively. A total of 480 shrimp juveniles with initial weight 1.84 ± 0.02 g were randomly divided into four diets with four replications, each replication consisted of 30 shrimp. The results revealed that shrimp fed the M-Zn diet had significantly higher percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and protein retention efficiency (PRE) than those fed the other diets. The significantly higher concentration of glucose (GLU) in hemolymph was observed in shrimp fed the M-Zn diet. Shrimp fed the diets supplemented with zinc amino acid complex had significantly lower values of drip and thawing losses of whole shrimp or muscle compared to those fed the control and I-Zn diets, which indicated that shrimp fed the diets supplemented with zinc amino acid complex had a better water-holding capacity. Moreover, shrimp fed the Availa-Zn diet had significantly higher the activities of alkaline phosphatase (AKP), acid phosphatase (ACP) and lysozyme (LZM) in hepatopancreas than those fed the control and I-Zn diets. Meanwhile, shrimp fed the M-Zn and Availa-Zn diets showed an up-regulation of expression levels of Cu-Zn sod , akp , acp and lzm in hepatopancreas. Principal component analysis (PCA) and multivariate correlation analysis demonstrated that shrimp fed the experimental diets exhibited significant variations and shrimp fed the M-Zn diet showed better growth response and meat quality. These findings could contribute to provide scientific evidences into the business application of zinc amino acid complex. • Zinc amino acid complex had higher bioavailability compared to zinc sulfate. • Zinc amino acid complex could improve growth performance and feed utilization. • Zinc amino acid complex enhanced water-holding capacity of muscle and whole shrimp. • Shrimp fed zinc amino acid complex showed higher antioxidant ability and immunity. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the effects of different carbohydrate levels on the growth performance, glycogen accumulation in tissue, enzyme activities, and expression levels of genes related to hepatopancreatic glucose and lipid metabolism and insulin signaling pathway in swimming crab, Portunus trituberculatus for 8 weeks. The results indicated that crabs fed with the 60.0 g kg-1 carbohydrate diet exhibited the highest final body weight (FBW), percent weight gain (PWG), and specific growth rate (SGR) among all treatments. FBW, PWG, and SGR significantly decreased when dietary carbohydrate levels exceeded 240.0 g kg-1. Light microscopy results showed that dietary excessive carbohydrate levels will lead to vacuole, hepatopancreatic tubule lysis, and lipid droplets in hepatopancreas. Expression levels of genes involved into glucose transport, glucose and lipid metabolism, and insulin-like metabolism in the hepatopancreas were significantly influenced by dietary carbohydrate levels. In general, the results of present study demonstrated that dietary optimal carbohydrate levels could not only improve PWG and SGR but also influence the expression of genes involved in glucose, lipid, and insulin-like metabolism. The optimal actual carbohydrate level was estimated to be 87.8-98.4 g kg-1 based on broken-line and second-order polynomial regression analysis between PWG against dietary carbohydrate levels for juvenile Portunus trituberculatus. [ABSTRACT FROM AUTHOR]

This paper introduces a systematic design optimization approach for shells with pattern-guided infills, aiming to address both intuitive design requirements and considerations for additive manufacturing. The approach utilizes a density-based topology optimization method and assigns two sets of design variables to distinctly define the base, coating, and infill structures. By evolving the solid shells and enriched infills concurrently, the design optimization process ensures a cohesive integration of both components. To guide the infill design towards matching the geometrical features of a predefined pattern, a geometrical constraint is imposed on the infill field. Enhanced by an updated and approximate volume constraint, the infill materials with prescribed appearance performances are accordingly distributed in the base region. The simultaneous optimization of shell geometry and infill layout is then performed within the framework of minimum compliance topology optimization. A range of numerical results illustrate the effectiveness and robustness of the proposed approach. The topology optimized results demonstrate that a given pattern can directly control the design features of the infill in a visually explicit manner and the shell-infill composites ensure convenient manufacturability. [Display omitted] • Concurrent topology optimization of solid shells and enriched infills is realized. • The optimized infill materials exhibit a visual appearance of a predefined pattern. • The proposed method empowers designers and maintains convenience in manufacturing. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to evaluate the effects of replacement of fish oil (FO) with blending vegetable oils (VOs) on growth performance, antioxidant enzyme activities and fatty acid composition in tissue of swimming crab Portunustrituberculatus. Five isonitrogenous and isolipidic diets were formulated to contain VOs (colza oil: palm oil: linseed oil = 4:2:1) to replace 0 (the control diet), 250, 500, 750 and 1000 g/kg of FO (defined D0, D25, D50, D75, D100). Three hundred juvenile swimming crabs (initial weight 2.34 ± 0.08 g) were randomly stocked and sorted into 300 individual rectangle plastic baskets in three cement pools. Each treatment has three replicates, one replicate has 20 swimming crabs, and each diet fed 60 crabs distributed in 60 baskets. The results indicated that crabs fed the control diet showed significantly higher survival, final body weight, per cent weight gain (PWG), specific growth rate and moulting frequency, crude protein and crude lipid contents in muscles than those fed the D75 and D100 VO diets (p <.05). Crabs fed the D25 VO diet showed significantly higher concentration of triglyceride, low‐density lipoprotein cholesterol and total protein, activities of superoxide dismutase, catalase and glutathione peroxidase (GSH‐Px) in haemolymph than those fed the control diet (p <.05). Fatty acid composition in hepatopancreas was positively correlated with dietary composition. In summary, based on the PWG, the optimal replacement of FO with VOs was estimated to be 250 g/kg. These findings demonstrated that swimming crabs make better use of FO than VOs. [ABSTRACT FROM AUTHOR]

An eight-week feeding trail was carried out to investigate the impacts of different dietary arachidonic acid (ARA) supplementations on growth performance, antioxidant capacity, tissue fatty acid profiles, and lipid metabolism of mud crab (Scylla paramamosain) juvenile. Six isonitrogenous (480 g kg-1 crude protein) and isolipidic (80 g kg-1 crude lipid) diets were formulated to contain 0.40, 2.50, 4.60, 8.90, 12.50, and 15.70 g ARA kg-1 (dry matter), respectively. Each experimental treatment included 24 mud crab juveniles (initial weight 11.29 ± 0.09 g) and was assigned to triplicate groups (n = 3). Crabs fed diets with 2.50, 4.60, and 8.90 g kg-1 ARA presented significantly higher percent weight gain (PWG) and specific growth rate (SGR) than those fed the other diets. Based on two-slope broken-line and quadratic curve regression analysis of PWG against dietary ARA levels, optimal dietary ARA levels were determined to be 5.20 g kg-1 and 6.20 g kg-1, respectively. Crabs fed with 4.60 g kg-1 ARA diet showed the lowest activities of alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) in hemolymph among all treatments. In hemolymph and hepatopancreas, total antioxidant capacity (T-AOC), the activities of total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) as well as the contents of reduced glutathione (GSH) rose first and then dropped with the increase of dietary ARA levels, while the concentration of malondialdehyde (MDA) showed an opposite trend. Tissue fatty acid profiles reflected diets fatty acid compositions. The ARA contents in hepatopancreas and muscle significantly increased with the increase of dietary ARA levels. Furthermore, the areas of blasenzellen (B) cells and restzellen (R) cells were significantly downregulated with the increase of dietary ARA levels. Crabs fed with 0.40 g kg-1 ARA diet showed significantly higher gene expression levels of fatty acid synthase (fas) as well as acetyl-CoA carboxylase (acc) among all treatments. Relative gene expression levels of 6-phosphogluconate dehydrogenase (6pgd) as well as glucose-6-phosphate dehydrogenase (g6pd) have been significantly upregulated in 0.40 and 2.50 g kg-1 ARA groups. Relative gene expression level of fatty acid binding protein 1 (fabp1) significantly increased in 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA groups. However, the gene expression levels of fatty acid binding protein 4 (fabp4) as well as scavenger receptor class 2 (srb2) have not been influenced by dietary ARA levels. What is more, crabs fed diets with 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA had a significantly higher expression level of carnitine palmitoyltransferase 1 (cpt1) than those fed diets with 0.40 and 2.50 g kg-1 ARA. In summary, optimum dietary ARA can promote growth, enhance antioxidant capacity, and improve health of mud crab juveniles. It also demonstrated that lipogenesis has been restrained with the increasing dietary ARA levels. These findings could provide theoretical guidance and reference for the lipid nutrition research as well as the development of the commercial diet in mud crab. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was carried out to assess the effect of dietary krill meal on growth performance and expression of genes related to TOR pathway and antioxidation of swimming crab (Portunus trituberculatus). Four experimental diets (45% crude protein and 9% crude lipid) were formulated to obtain different replacements of fish meal (FM) with krill meal (KM); FM was replaced with KM at 0% (KM0), 10% (KM10), 20% (KM20), and 30% (KM30); fluorine concentration in diets were analyzed to be 27.16, 94.06, 153.81, and 265.30 mg kg-1, respectively. Each diet was randomly divided into 3 replicates; ten swimming crabs were stocked in each replicate (initial weight, 5.62 ± 0.19 g). The results indicated that crabs fed with the KM10 diet had the highest final weight, percent weight gain (PWG), and specific growth rate (SGR) among all treatments (P < 0.05). Crabs fed with the KM0 diet had the lowest activities of total antioxidant capacity (T-AOC), total superoxide dismutase (SOD), glutathione (GSH), and hydroxyl radical scavenging activity and had the highest concentration of malondialdehyde (MDA) in the hemolymph and the hepatopancreas (P < 0.05). In the hepatopancreas, the highest content of 20:5n-3 (EPA) and the lowest content of 22:6n-3 (DHA) were shown in crabs fed with the KM30 diet among all treatments (P < 0.05). With the substitution level of FM with KM gradually increasing from 0% to 30%, the color of the hepatopancreas changed from pale white to red. Expression of tor, akt, s6k1, and s6 in the hepatopancreas was significantly upregulated, while 4e-bp1, eif4e1a, eif4e2, and eif4e3 were downregulated with dietary replacement of FM with KM increasing from 0% to 30% (P < 0.05). Crabs fed with the KM20 diet had notably higher expression of cat, gpx, cMnsod, and prx than those fed with the KM0 diet (P < 0.05). Results demonstrated that 10% replacement of FM with KM can promote growth performance and antioxidant capacity and notably upregulate the mRNA levels of genes related to TOR pathway and antioxidant of swimming crab. [ABSTRACT FROM AUTHOR]

Carbohydrate is the cheapest source of energy among the three major nutrient groups, an appropriate amount of carbohydrates can reduce feed cost and improve growth performance, but carnivorous aquatic animals cannot effectively utilize carbohydrates. The objectives of the present study are aimed at exploring the effects of dietary corn starch levels on glucose loading capacity, insulin-mediated glycemic responses, and glucose homeostasis for Portunus trituberculatus. After two weeks of feeding trial, swimming crabs were starved and sampled at 0, 1, 2, 3, 4, 5, 6, 12, and 24 hours, respectively. The results indicated that crabs fed diet with 0% corn starch exhibited lower glucose concentration in hemolymph than those fed with the other diets, and glucose concentration in hemolymph remained low with the extension of sampling time. The glucose concentration in hemolymph of crabs fed with 6% and 12% corn starch diets reached the peak after 2 hours of feeding; however, the glucose concentration in hemolymph of crabs fed with 24% corn starch attained the highest value after 3 hours of feeding, and the hyperglycemia lasted for 3 hours and decreased rapidly after 6 hours of feeding. Enzyme activities in hemolymph related to glucose metabolism such as pyruvate kinase (PK), glucokinase (GK), and phosphoenolpyruvate carboxykinase (PEPCK) were significantly influenced by dietary corn starch levels and sampling time. Glycogen content in hepatopancreas of crabs fed with 6% and 12% corn starch first increased and then decreased; however, the glycogen content in hepatopancreas of crabs fed with 24% corn starch significantly increased with the prolongation of feeding time. In the 24% corn starch diet, insulin-like peptide (ILP) in hemolymph reached a peak after 1 hour of feeding and then significantly decreased, whereas crustacean hyperglycemia hormone (CHH) was not significantly influenced by dietary corn starch levels and sampling time. ATP content in hepatopancreas peaked at 1 h after feeding and then decreased significantly in different corn starch feeding groups, while the opposite trend was observed in NADH. The activities of mitochondrial respiratory chain complexes I, II, III, and V of crabs fed with different corn starch diets significantly increased first and then decreased. In addition, relative expressions of genes related to glycolysis, gluconeogenesis, glucose transport, glycogen synthesis, insulin signaling pathway, and energy metabolism were significantly affected by dietary corn starch levels and sampling time. In conclusion, the results of the present study reveal glucose metabolic responses were regulated by different corn starch levels at different time points and play an important role in clearing glucose through increased activity of insulin, glycolysis, and glycogenesis, along with gluconeogenesis suppression. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to investigate the effects of DL‐methionyl‐DL‐methionine (Met‐Met) supplementation in different fishmeal levels on growth performance, antioxidant and immune response of juvenile Pacific white shrimp, Litopenaeus vannamei. Eight isonitrogenous and isolipidic experimental diets were formulated to meet the nutrient requirements of Pacific white shrimp. The supplemental amount of fishmeal in diets without essential amino acid supplementation are 200 g/kg (F20), 100 g/kg (F10), 50 g/kg (F5) and 0 g/kg (F0), and with essential amino acid supplementation are 200 g/kg (M20), 100 g/kg (M10) 50 g/kg (M5) and 0 g/kg (M0) respectively. The results indicated that shrimp fed the F5 and F0 diets had significantly lower final body weight (FBW), per cent weight gain (PWG), specific growth rate (SGR) and higher feed conversion ratio (FCR) compared with those fed the F20 diet (p <.05). Glucose (GLU), triacylglycerol (TG) and cholesterol (CHO) concentration in haemolymph significantly decreased with fishmeal supplementation decreasing from 200 g/kg to 0 g/kg (p <.05). Met‐Met supplementation in low fishmeal diets significantly reduced the content of malondialdehyde (MDA), increased the activities of acid phosphatase (ACP) and lysozyme (LZM) in hepatopancreas, as well as increasing the activity of total antioxidant capacity (T‐AOC) in haemolymph (p <.05). Meanwhile, shrimp fed M5 and M0 diets had significant upregulation of gene expression of acp, lzm (immune‐related), RagC and s6k (TOR signalling pathway‑related) in hepatopancreas (p <.05). In conclusion, the present study demonstrated that dietary Met‐Met supplementation could improve the growth performance and the abilities of antioxidant and non‐specific immunity of Pacific white shrimp by reducing MDA concentration, increasing T‐AOC, ACP and LZM activities, and upregulating gene expression level of immune (acp and lzm) and TOR signalling pathway (RagC, and s6k). Moreover, Pacific white shrimp fed low fishmeal diets had the positive response of well‐balanced amino acid, and the results will provide further insight into the possibility of reducing fishmeal content in the commercial feed of shrimp. [ABSTRACT FROM AUTHOR]

The eggshell color of avian species is an important trait that is predominantly determined by the pigments biliverdin and protoporphyrin. Various factors affect eggshell pigment deposition and coloration; however, the underlying mechanisms remain unclear. We analyzed the hepatic transcriptomes and metabolomes of Changshun green-shell hens laying dark green and light green eggs to investigate the potential role of the liver in regulating the intensity of the green eggshell color. In total, 350 differentially expressed genes and 211 differentially altered metabolites were identified. Gene set enrichment analysis revealed that the enriched pathways and Gene Ontology (GO) terms were mainly associated with energy, immunity, and nutrient metabolism. Metabolite set enrichment analysis revealed that the enriched pathways were mainly associated with amino acid, vitamin, bile acid, and lipid metabolism. Moreover, gene–metabolite interaction network analysis revealed 1 subnetwork. Most genes and metabolites in this subnetwork were determined to be related to melanin metabolism and transport. In conclusion, our results suggest that hepatic melanin metabolism and transport are critical for eggshell coloration. Six candidate genes (CDKN2B, DDC, PYCR1, ABCG5, SLC3A1 , and P2RX2) and 7 candidate metabolites (serotonin, 5-hydroxyindoleacetic acid, ornithine, acetylcholine, L -tryptophan, D -ornithine, and ADP) were suggested to play important roles in this process. Meanwhile, this study suggests that changes in hepatic energy metabolism, immune status, antioxidation activity, nutrient availability, and bile acid synthesis can impair eggshell coloration. [ABSTRACT FROM AUTHOR]

The sterol regulatory element-binding proteins (SREBPs) are a family of transcription factors known to activate the transcription of genes encoding key lipogenic enzymes. The present study reports on the molecular cloning, tissue expression and nutritional regulation of SREBP-1 from the swimming crab Portunus trituberculatus (Miers, 1876). The SREBP-1 full-length cDNA was 3785 bp, encoding a polypeptide of 1039 amino acids. Quantitative PCR analysis revealed that SREBP-1 expression was detected in various tissues, and the significantly higher expression levels were found in eyestalk and hepatopancreas compared with other tested tissues. Additionally, the effects of dietary iron on expression of SREBP-1 were investigated, and the results indicated that SREBP-1 expressions were down-regulated by crabs fed diets containing 218.9 and 373.9 mg/kg iron compared with that fed the basal diet (55.2 mg/kg). Suggesting that the relative expression level of SREBP-1 can be suppressed by dietary iron supplementation. These findings provide further insight into the regulatory capacity of SREBP-1 in the lipid anabolism of P. trituberculatus. Résumé: Les SREBPs (protéines de liaison à l'élément de régulation des stérols) sont une famille de facteurs de transcription connus pour activer la transcription de gènes codant des enzymes lipogéniques. Cette étude présente le clonage moléculaire, l'expression des tissus et la régulation de la nutrition de SREBP-1 du crabe Portunus trituberculatus (Miers, 1876). La longueur totale de l'ADNc de SREBP-1 est de 3785 pb, codant un polypeptide de 1039 acides aminés. Une analyse par PCR quantitative révèle que l'expression de SREBP-1 a été détectée dans différents tissus, et que l'expression significativement la plus élevée a été trouvée dans le pédoncule oculaire et l'hépatopancréas par comparaison aux autres tissus testés. De plus, les effets du fer alimentaire sur l'expression de SREBP-1 a été examiné, et les résultats indiquent que, par comparaison avec un régime de base (55,2 mg kg−1 de fer), les expressions de SREBP-1 ont été régulées à la baisse chez les crabes nourris avec un régime contenant 218,9 et 373,9 mg kg−1 de fer. Ce qui laisse supposer que le niveau d'expression relatif de SREBP-1 peut être réprimé par une supplémentation en fer alimentaire. Ces résultats fournissent plus d'information sur la capacité régulatrice de SREBP-1 dans le metabolisme lipidique de P. trituberculatus. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, antioxidant enzyme activities and biochemical composition of juvenile swimming crab Portunus trituberculatus of initial weight 2.34 ± 0.08 g. Four different diets were formulated to contain fish oil (FO), soybean oil (SO), linseed oil (LO) or palm oil (PO). The highest final body weight, weight gain, specific growth rate and molting frequency were observed in crabs fed the FO diet. Crabs fed the SO diet showed higher glutathione peroxidase, superoxide dismutase (SOD) and catalase (CAT) activities in both serum and hepatopancreas than those fed the FO diet. The lowest malondialdehyde concentration in hepatopancreas and serum were occurred at crabs fed the SO diet. Crabs fed the LO diet had significantly higher SOD and CAT activities in hepatopancreas compared with those fed the FO diet. Crabs fed the PO diet had the highest activities of fatty acid synthase and carnitine palmitoyltransferase 1 activities in hepatopancreas among all treatments. Fatty acid compositions both in hepatopancreas and muscle reflected those of diets. Overall, these findings demonstrated that physiological–biochemical characteristics and lipid metabolism were significantly regulated by different dietary lipid sources. Moreover, dietary SO and LO supplementation could improve antioxidant ability. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effects of dietary inositol level (0.86, 1.34, 1.40, 2.30, 3.88 and 7.50 g kg−1) on glucose and lipid homeostasis in Litopenaeus vannamei. The results indicated that the contents of inositol, phosphatidyl inositol (PI) and glycogen in hepatopancreas and muscle, very low-density lipoprotein (VLDL) in hepatopancreas and hemolymph, the activity of carnitine palmitoyl-transferase (CPT1) and the expression of hmit and inox were positively related to the dietary inositol levels, while the contents of glucose (GLU), crustacean hyperglycemic hormone (CHH), triglyceride (TG), cholesterol (CHO) and non-esterified fatty acid (NEFA) in hemolymph and the expression of imp , pepck , g6pc and fbp were negatively correlated with the dietary inositol level. TG content, phosphoenolpyruvate carboxykinase (PEPCK) activity and the expression levels of srebp , fa s, acc1 , g6pd and 6gpd in shrimp fed 3.88 and 7.50 g kg−1 inositol diets were significantly lower compared with shrimp fed the basal diet, while the expression of cpt1 , aco , fabp , fatp and idir were showed the reverse change trend (P < 0.05). The activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK) and the expression levels of ir, irs1 , pi3k and akt were significantly increased as dietary inositol levels ranged from 1.40 to 7.50 g kg−1, while the expression levels of gsk-3β and foxo1 significantly down-regulated. Hepatopancreas R cells number in shrimp fed 2.30, 3.88 and 7.50 g kg−1 inositol diets were significantly increased compared with shrimp fed 0.86 g kg−1 inositol diet, while the diameters and areas showed an opposite trend. In addition, dietary inositol supplementation significantly increased hemolymph insulin like peptide (ILP) content but had no significant effect on high density lipoprotein cholesterol (HLD C) content in hemolymph, hepatic lipase (HL) activity and the ratio of n-3/ n-6 PUFA and DHA/EPA in hepatopancreas. In conclusion, appropriate dietary inositol could positively regulate the Insulin-PI3K-Akt pathway to promote glucose utilization and maintain the normal accumulation of glycogen and lipids required for development, while high dietary inositol could promote lipid mobilization and prevent hepatopancreas lipids deposition by negatively regulating the Insulin-PI3K-Akt pathway, improving ILP sensitivity and enhancing VLDL synthesis, which may therefore be an important mechanism in the action of inositol on glucose and lipid metabolism. These findings provided further insight and understanding of mechanisms by which dietary inositol regulated glucose and lipid metabolism in L. vannamei. Possible pathways by which appropriate inositol level (blue line) and high inositol level (red line) regulation of glucose and lipid metabolism in L. vannamei. The line ends with arrows indicating facilitation, and the line ends with horizontal lines indicating inhibition. The black arrow indicates the path direction. Upward arrows represent up-regulation and downward arrows represent down-regulation. Ino, inositol; H-Ino, high level inositol level. PI, phosphatidylinositol; ILP, insulin like peptide; Glu, glucose; MIOX, myo-inositol oxygenase; IMP, inositol monophosphatase. [Display omitted] • Dietary inositol level affected the deposition of inositol and PI in tissues. • Dietary appropriate inositol promoted the development of hepatopancreas R cells. • Dietary appropriate inositol positively regulated the Insulin-PI3K-Akt pathway. • Optimal inositol in diet promote glucose utilization and moderate lipid accumulation. [ABSTRACT FROM AUTHOR]

A six-week feeding trial was conducted to evaluate the effects of dietary isoleucine level on growth, myofiber histology, and mRNA levels of genes related to amino acid, glucose and lipid metabolism in swimming crab (Portunus trituberculatus). Six isonitrogenous and isolipidic diets (45% protein and 8% lipid) were formulated to contain graded levels of isoleucine (Ile), with the analyzed levels of isoleucine being 0.69%, 1.06%, 1.32%, 1.78%, 2.03% and 2.38%, respectively. A total of 180 crabs (initial weight 16.30 ± 0.01 g) were housed individually in 180 plastic baskets with 30 crabs assigned to each diet, divided randomly into three replicates of 10 crabs. Each crab was fed twice at 08:00 and 18:00 with a daily feeding ration of 6–8% of crab body weight. Eight crabs from each replicate group were sampled and dissected after the feeding trial to provide hemolymph for biochemical analysis, hepatopancreas for proximate composition, amino acid profile enzyme activity, and gene expression, and muscle for proximate composition, amino acid profile and histology. The results indicated that final weight, percent weight gain and specific growth rate increased significantly as dietary isoleucine level increased from 0.69% to 1.78%, and then decreased with further increased dietary isoleucine. Crabs fed the diets with 1.78%, 2.03% and 2.38% isoleucine showed significantly higher muscle protein contents (17.80%, 17.99% and 17.65% of wet mass) than crabs fed lower levels of isoleucine. The highest concentrations of IGF1R and CHH in hemolymph (187.95 and 529.42 pg ml−1, respectively) and hepatopancreas (24.18 and 38.69 pg ml−1, respectively) were observed in crabs fed the diet with 1.32% isoleucine. Hepatopancreas expression levels of genes related to amino acid metabolism, including s6k1 , bcat , alt and ast , were up-regulated in crabs fed 1.32% isoleucine compared to the other groups, whereas the expression level of tor decreased as dietary isoleucine increased. Expression levels of genes related to glucose intake, such as pi3k , igf1r and glut1 , were significantly higher in crabs fed 1.32% isoleucine compared to crabs fed 0.69% isoleucine. Expression levels of genes related to gluconeogenesis (pepck and g6pase) were significantly higher in crabs fed 0.69% isoleucine than in crabs fed the diets with 1.32% and 1.78% isoleucine. In contrast, expression levels of genes related to glycolysis, including hk , gk and pk , were up-regulated in crabs fed 1.32% isoleucine compared to crabs fed 0.69% isoleucine. Gene expression levels of regulatory factors related to lipid metabolism (foxo , sirt1 and sirt3) were significantly higher in crabs fed 1.32% isoleucine compared to crabs fed the other treatments, while expression levels of genes related to lipolysis (hsl and cpt2) were significantly up-regulated in crabs fed the diets with 1.32% and 1.78% isoleucine. Expression levels of key lipogenesis genes (fas and acc) were down-regulated in crabs fed the diets with 1.32% and 1.78% isoleucine compared to those fed 0.69% isoleucine. Muscle histology indicated that crabs fed the diets with 1.32% and 1.78% isoleucine had significantly lower densities of myofibers (21.67 and 17.33 N/ mm2) compared to crabs fed 0.69% isoleucine. In conclusion, based on percent weight gain, the optimal isoleucine requirement of juvenile swimming crab was calculated to be 1.57% of diet (3.49% dietary protein) by quadratic curve model. Thus, appropriate dietary isoleucine levels (1.32–1.78%) promoted amino acid metabolism and protein synthesis, increased protein deposition, and altered myofiber structure of muscle and, in addition, promoted lipolysis and glycolysis, and reduced lipogenesis and gluconeogenesis in juvenile swimming crab. • Based on PWG, the optimal dietary isoleucine requirement for P. trituberculatus was to be 1.57%. • Increasing dietary isoleucine in the range 1.78%–2.38% promoted protein deposition in body muscle. • Isoleucine at 1.32% of diet up-regulated expression levels of genes related to amino acid metabolism in hepatopancreas. • Isoleucine at 1.32% of diet increased hepatic glycogen content by activating glycolysis and suppressing gluconeogenesis. • 1.32%−1.78% isoleucine of diet increased hepatopancreatic lipid catabolism via activation of the foxo-sirt1/sirt3 pathway. [ABSTRACT FROM AUTHOR]

Cholesterol and phospholipid play an important role in growth, molt and reproduction for crustaceans, although dietary optimum requirement of cholesterol and phospholipids has been determined for Portunus trituberculatus , but it is still unclear whether there was an interaction on each other. Therefore, an eight-week feeding trial was conducted to evaluate the interactive effects of dietary cholesterol and phospholipid levels on growth performance, fatty acid composition in hepatopancreas and the expression of genes related to cholesterol and phospholipid metabolism of Portunus trituberculatus. Six isonitrogenous and isolipid diets were formulated to contain two cholesterol levels (0 % and 0.5 %) and three phospholipid levels (0 %, 2 % and 4 %). The results indicated that specific growth rate (SGR) significantly increased with the increase of dietary phospholipid levels, however, there were no interactive effects between dietary cholesterol and phospholipid on percent weight gain (PWG) and SGR (P > 0.05). The concentration of total-cholesterol (T-CHO) and triacylglycerol (TAG) in hemolymph significantly affected by the interaction between cholesterol and phospholipid (P < 0.05), crabs fed diets with 0.5 % cholesterol supplementation had higher low-density lipoprotein cholesterol (LDL-C) concentration in hemolymph than those fed diets without cholesterol supplementation regardless of phospholipid supplementation (P < 0.05). TAG and LDL-C concentration in hepatopancreas were significantly affected by the interaction between cholesterol and phospholipid (P < 0.05), crabs fed diets with 0.5 % cholesterol supplementation had significantly higher T-CHO and LDL-C concentration in hepatopancreas than those fed diets without cholesterol supplementation (P < 0.05). There was a significant interaction between dietary cholesterol and phospholipid on activity of catalase (CAT) and the concentration of glutathione (GSH) and malondialdehyde (MDA) in hepatopancreas (P < 0.05), and crabs fed diets with cholesterol supplementation had higher superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in hepatopancreas than those fed diets without cholesterol supplementation (P < 0.05). Moreover, EPA, LC-PUFA, n-3 PUFA, n-3/n-6 PUFA and DHA/E P A in hepatopancreas were significantly affected by the interaction between dietary cholesterol and phospholipid (P < 0.05). The expression of adenosine triphosphate binding cassette transporter G1 (abcg1), C-type 1 class Niemann-Pick protein (npc1), scavenger receptor B (srb) and low-density lipoprotein receptor (ldlr) were up-regulated by dietary cholesterol and phospholipid levels (P < 0.05). In conclusion, the results indicated that dietary appropriate cholesterol and phospholipid levels could significantly improve growth performance and promote cholesterol metabolism. • Interaction between dietary cholesterol and phospholipid did not affect growth performance of swimming crabs. • Interaction between dietary cholesterol and phospholipid could enhance antioxidant capacity of swimming crab. • Dietary cholesterol regulated cholesterol metabolic pathways in hepatopancreas of swimming crab. • Interaction between cholesterol and phospholipid up-regulated the expression of genes related to cholesterol and phospholipid metabolism. • Interaction between cholesterol and phospholipid could promote cholesterol transport and transformation. [ABSTRACT FROM AUTHOR]

• Faba bean changed fatty acids composition in white muscle of carps. • Faba bean changed oxidation state in white muscle and hepatopancreas of carps. • Faba bean caused myofiber atrophy and collagen turnover interruption in carps. In order to further explain the fillet texture improvement of Yellow River carp (Cyprinus carpio) fed with faba bean (Vicia faba L.), a three-month rearing trial was conducted to investigate fatty acid composition, antioxidant capacity, myofiber development, collagen deposition and transcriptome in white muscle of two farmed carp groups (One was fed only faba bean, the other was fed commercial diet). As a strong oxidant, faba bean changed fatty acids composition in white muscle, especially DHA and EPA, up-regulated the levels of reactive oxygen species (ROS) and down-regulated major antioxidant enzyme activities in the hepatopancreas and white muscle. Through the analysis of transcriptome and subsequent verification analysis, we speculated that the increase of ROS led to the decrease of myofiber diameter and collagen metabolism. This study provides a theoretical basis for further understanding the regulation of faba bean on fillet texture characteristic of Yellow River carp. [ABSTRACT FROM AUTHOR]

An eight-week feeding trial was conducted to evaluate the effect of dietary replacement of fish meal with low-gossypol cottonseed protein concentrate (CPC) on growth performance, body composition, amino acid profiles in tissues, antioxidant capacity and the expression levels of genes related to protein metabolism and inflammation for juvenile swimming crab (Portunus trituberculatus). Six isonitrogenous and isolipidic diets (450 g kg−1 protein and 80 g kg−1 lipid) were formulated to contain graded levels of CPC, and fish meal was replaced with CPC at 0, 10%, 20%, 30%, 40% and 60% levels (CPC00, CPC10, CPC20, CPC30, CPC40 and CPC60), free gossypol concentrations in experimental diets were analyzed to be 0, 32.62, 66.10, 106.71, 133.13, 192.21 mg kg−1 respectively. Arginine, lysine and methionine were added to ensure consistency of these three essential amino acids in all experimental diets. Each diet was randomly assigned to triplicate groups of 30 juvenile swimming crabs (approximately initial weight 7.59 ± 0.06 g) that were stocked in rectangle plastic baskets. Results of present study indicated that crabs fed the CPC60 diet had the lower final weight (FW), percent weight gain (PWG), specific growth rate (SGR) and feed efficiency (FE) than those fed the CPC20 diet, and crabs fed the CPC20 and CPC30 diets had the highest survival among all treatments, and the lowest survival was occurred at crabs fed the CPC60 diet. The hepatopancreas color was blackened with the replacement levels of fish meal with CPC increasing from 0% to 60%. Free gossypol concentration in hepatopancreas significantly increased with increase of dietary replacement levels of fish meal with CPC. Crabs fed the CPC40 and CPC60 diets had lower lipid content in whole body than those fed the other diets. Arginine, lysine, methionine and isoleucine contents in muscle were significantly influenced by dietary replacement levels of fish meal with CPC. ALT, AST, TP, ALB, HDL and ALP in hemolymph, and T-AOC, ALT, AST, SOD, GSH, GSH-ST in hepatopancreas were significantly affected by dietary replacement of fish meal with CPC. Dietary replacement levels of fish meal with CPC could influence the expressions of genes related into protein metabolism such as tor , akt , s6 , s6k1 , 4ebp1 , eif4e1a , eif4e2 , eif4e3 , antioxidant and immune such as gpx, cat, cMnsod and lysozyme , as well as growth such as tlr4 , irak4 , myd88 , traf6 , and inflammation such as relish. In conclusion, based on two slope broken-line and quadratic broken-line regression analysis of PWG against the dietary replacement of fish meal with CPC, the optimal replacement level of fish meal with CPC was estimated to be 19.07% and 22.73% for juvenile swimming crab, respectively. Results demonstrated that CPC could partially replace fish meal, but had no negative effects on growth performance, antioxidant activity and immunity of swimming crab. • The optimal replacement level of FM with CPC was 19.07–22.73% for swimming crab based on PWG. • Hepatopancreas free gossypol concentration significantly increased with increase of dietary CPC. • Replacement of FM with CPC influenced expression of genes related to mTOR pathway and inflammation. [ABSTRACT FROM AUTHOR]

An eight-week feeding trial was conducted to evaluate the influence of an alternating linseed oil (LO) and fish oil (FO) feeding strategy in black seabream A. schlegelii (initial weight, 8.49 ± 0.01 g). Two isonitrogenous and isolipidic feeds were formulated to contain FO or LO, and used to enable three feeding strategy treatments termed FO (feeding the FO diet for 8 weeks), LO (feeding the LO diet for 8 weeks) and FO re-feeding (feeding LO for 4 weeks then FO for 4 weeks). Fish in the FO re-feeding and FO groups had significantly higher final body weights (FBW), weight gains (WG), specific growth rates (SGR) but lower muscle lipid content than fish in the LO group. In muscle, the FO re-feeding strategy restored eicosapentaenoic and docosahexaenoic acid contents to 82.67% and 83.84%, respectively, of those in fish fed the FO treatment. In addition, the FO re-feeding strategy significantly down-regulated the expression levels of genes related to long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis and lipogenesis, including fatty acyl desaturase (fads2), elongase of very long-chain fatty acids 4a (elovl4a) and sterol regulatory element-binding protein-1 (srebp-1) compared to fish fed the LO treatment. Similarly, the hepatic Srebp-1c concentration in fish in the FO re-feeding group was markedly lower than in fish in the LO treatment group. Expression of the lipid catabolism gene adipose triglyceride lipase (atgl) was up-regulated in fish in the FO re-feeding group compared with fish in the LO group. Overall, the present study indicated that a strategy of re-feeding FO following feeding LO for four-week promoted growth, mitigated lipid accumulation in muscle, and effectively restored muscle n-3 LC-PUFA levels in A. schlegelii. • Dietary LO had an adverse effect on growth in A. schlegelii. • Growth and feed utilization were recovered by FO re-feeding in A. schlegelii. • FO re-feeding could effectively restore DHA and EPA contents in muscle. • After FO re-feeding, DHA and EPA were better retained in muscle than in liver. • FO-refeeding reduced lipid accumulation by regulating gene expression. [ABSTRACT FROM AUTHOR]

n-3 LC-PUFA is vital to crustaceans for the growth, molting and development, while the precise molecular mechanism underlying the regulation of n-3 LC-PUFA is poorly investigated. Herein, an 8-week nutritional trial and transcriptome analysis were used to investigate the impacts of dietary n-3 PUFA lipid sources including fish oil (FO), krill oil (KO) and linseed oil (LO) on the transcriptome characteristics in hepatopancreas of swimming crab (Portunus trituberculatus). Crabs fed KO diet had significantly higher percent weight gain (PWG) and molting ratio (MR) than those of crabs fed other diets. The transcriptome analysis reveled that a total of 6567 unigenes were annotated in KEGG database, of which the expression of 1126 significantly altered in the KO vs FO group, while the expression of 921 unigenes changed in the LO vs FO group. The differentially expressed genes (DEGs) in KO vs FO comparison group involved in fat digestion and absorption, ABC transporters, adipocytokine signaling pathway, protein digestion and absorption, glycolysis/gluconeogenesis and HIF-1 signaling pathway. While dietary LO significantly altered the expression levels of genes involved in carbohydrate digestion and absorption, mineral absorption, protein processing in endoplasmic reticulum, glycosphingolipid biosynthesis and insect hormone biosynthesis. In addition, dietary KO significantly up-regulated the expression levels of cyp18a1 (participates in the process of ecdysteroids biosynthesis and further controls the molting of crustaceans), tryp (trypsin-like serine proteinases, resists the pathogen invasion), pla2 (phospholipase A2, regulates different inflammatory processes), ABC transporter (ATP-binding cassette transporter, transports amino acids, lipids and proteins into and out of the cell), cpt1 (carnitine palmitoyltransferase I, the major rate-limiting enzyme of mitochondrial fatty acid β-oxidation) and slc2 (solute carrier 2, mediates bidirectional glucose transport). Meanwhile, dietary LO could significantly down-regulated the expression level of cyp315a1 compared to dietary FO. To sum up, swimming crab fed with dietary krill oil could not only enhance the transport of glucose, lipids, fatty acids and other substrates, but also up-regulate the expression levels of genes related to molting, immunity and energy metabolism to promote molting and growth of swimming crab. The present study revealed the molecular responses of crabs to different dietary n-3 PUFA lipid sources, and further provided important clues with respect to elucidating the molecular mechanisms underlying the regulation of EPA and DHA on the molting and growth of swimming crab. • Dietary n-3 PUFA lipid sources affected the transcriptome of hepatopancreas of crab. • Dieatry n-3 PUFA mainly influenced molting, immunity and metabolism of crab. • CYP18A1 and CYP315A1 may play a key role in the molting of swimming crab. • Dietary krill oil may enhance the transport of a variety of substrates. [ABSTRACT FROM AUTHOR]

• Dietary oils affect the composition of lipid molecules in hepatopancreas of crab. • Dietary oils affect stereospecific position of fatty acids in glycerolipids in crab. • Dietary krill oil raises deposition of 20:5n-3 and 22:6n-3 at sn-2 in phospholipids. • Fish oil intake promotes deposition of EPA and DHA at sn-1,2,3 in triglyceride. • LC-PUFA biosynthesis and dietary oils could affect the distribution of fatty acids. While tissue fatty acid compositions reflect that of the dietary lipid source, little information is available on how dietary oils modify lipid class and molecular species profiles in hepatopancreas of crustacean. Herein, an 8-week nutritional trial and untargeted lipidomic analysis were used to investigate the impacts of dietary n-3 PUFA lipid sources including fish oil, krill oil and linseed oil on the lipidomic characteristics of hepatopancreas of swimming crab (Portunus trituberculatus). Dietary krill oil significantly increased distribution of 20:5n-3 and 22:6n-3 at sn-2 in phosphatidylcholine and phosphatidylethanolamine compared to fish oil. Fish oil intake promoted the deposition of 20:5n-3 and 22:6n-3 at sn-1,2,3 in triglyceride compared to linseed oil, which significantly increased the specific accumulation of 18:3n-3 at sn-1,3 in triglyceride and sn-2 in phosphatidylcholine and phosphatidylethanolamine. The study revealed metabolic responses to different dietary n-3 PUFA in swimming crab, which provided novel insight into the lipid nutrition of crustacean. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to evaluate the effects of replacement of fish meal (FM) with poultry by-product meal (PBM) on growth performance, feed utilization and expression of genes involved in protein metabolism in juvenile black sea bream (Acanthoparus schlegelii). Six isonitrogenous (42%) and isolipidic (11%) experimental diets were formulated to replace 0% (control diet), 10%, 20%, 30%, 40% and 60% protein from FM with PBM. All the diets except the control diet were supplemented with lysine and methionine to keep same lysine and methionine levels among all diets. A total of 360 fish (approximately initial weight, 0.46 ± 0.02 g) were randomly stocked and sorted in 18,300-L cylindrical fiberglass tanks, each diet was randomly assigned to triplicate groups of 20 juvenile black sea bream and fed twice each day to apparent satiation. The results showed that survival ranged from 88.33 to 93.33%, and there were no significant differences among all treatments (p >.05). Final body weight (FBW) and percent weight gain (PWG) significantly increased with dietary replacement levels of FM with PBM increasing from 0% to 30%, and significantly decreased when replacement of FM with PBM further increased from 30% to 60% (p <.05) , fish fed the 30% replacement of FM with PBM diet had higher FBW and PWG than those fed the other diets. Based on PWG against replacement levels of FM with PBM, A two-slope broken-line model analysis indicated that the optimal replacement of FM with FBM is to be 28.30%. Proximate composition in whole body did not show significant differences among all dietary treatments (p >.05). Higher hepatosomatic index (HSI) was observed in fish fed the 30% replacement of FM with PBM compared to the control and other diets, however, viscerosomatic index (VSI) and condition factor (CF) were not significantly influenced by the replacement of FM with PBM (p >.05). Fish fed the diet containing 30% replacement of FM with PBM had higher lysine and methionine concentration in muscles than those fed the other diets, however, other essential or non-essential amino acids in muscle were not significantly affected by dietary replacement of FM with PBM. The relative expressions of igf1 , tor , s6k1 , pi3k and akt were significantly up-regulated when replacement levels of FM with PBM increased from 0% to 30%, however, the expression levels of these genes significantly down-regulated with the further increase of replacement level of FM by PBM (p <.05). Moreover, the lowest expression of 4e-bp2 was occurred at fish fed the 30% replacement of FM with PBM among all treatments. In summary, the results of present study indicated that dietary PBM supplementation could be an alternative protein source for black sea bream, and 30% replacement of FM with PBM could improve growth and up-regulate the relative expression of genes involved in protein metabolism. • PBM significantly improved the growth performance and feed utilization of black sea bream. • The optimum substitution level of dietary PBM for maximum weight gain was 28.30%. • Dietary PBM significantly influenced the protein metabolism in relation to gene expression. [ABSTRACT FROM AUTHOR]

An 8-week feeding trail was conducted in Acanthopagrus schlegelii with an initial body weight of 8.34 ± 0.01g. Three isonitrogenous diets were formulated, (1) Control: medium-fat diet (12%); (2) HFD: high-fat diet (18%); (3) HFD + FF: high-fat diet with fenofibrate (0.15%). Liver histological analysis revealed that, compared to HFD, vacuolar fat drops were smaller and fewer in fish fed fenofibrate. Expression of lipid catabolism regulator peroxisome proliferator-activated receptor alpha (pparα) was up-regulated by fenofibrate compared with HFD. In addition, fenofibrate significantly increased the expression level of silent information regulator 1 (sirt1). Meanwhile, the expression level of anti-inflammatory cytokine interleukin 10 (il-10) in intestine was up-regulated, while pro-inflammatory cytokine interleukin 1β (il-1β) in liver and intestine were down-regulated by dietary fenofibrate supplementation. Overall, the present study indicated that fenofibrate reduced fat deposition and attenuated inflammation response caused by HFD partly through a pathway involving regulation of pparα and sirt1. • Explored how dietary fenofibrate impacts lipid metabolism and inflammatory responses in fish. • Fenofibrate significantly increased the expression level of sirt1 and pparɑ compared with HFD. • Fenofibrate up-regulated the il-10 , while il-1β were down-regulated. • Compared to HFD, vacuolar fat drops were smaller and fewer in fish fed fenofibrate. [ABSTRACT FROM AUTHOR]