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This study investigated the responses of glucolipid metabolism in gibel carp, the CAS III strain (A strain, 7.14 ± 0.23 g) and the Dongting strain (DT strain, 7.72 ± 0.54 g), following acute hypoxia/reoxygenation. The effects of hypoxia (0.39 ± 0.02 mg/L) and reoxygenation (8.30 ± 0.30 mg/L) were examined in both strains after exposure for 2 h. The results revealed significantly enhanced PI3K/AKT pathway and AMPK/HIF-1α pathways, along with upregulated expression of glucose-6-phosphatase (g6pase) and lipid synthesis-related genes (acc and fas) in both gibel carp strains following acute hypoxia (P < 0.05). The observed increase in plasma glucose levels during acute hypoxia may be related to elevated expression of g6pase (P < 0.05). Regarding the genotype, the A strain exhibited significantly higher expression of glucose metabolism-related genes (pk and pepck) in the liver compared to the DT strain (P < 0.05). Conversely, the expression of lipid metabolism-related genes (hsl, lpl, pparα, cpt1a, and aco3) were significantly lower in the A strain compared to the DT strain (P < 0.05). In both strains of gibel carp, reoxygenation resulted in significant activation of the PI3K/AKT and AMPK/mTOR pathways, accompanied by upregulated expression of glucose metabolism-related genes (gk, 6pfk, foxo1a, fbpase, and pepck) and lipid synthesis-related genes (srebp-1, acly, and acc) (P < 0.05). Notably, the A strain exhibited increased transcripts of glucose metabolism-related genes (gk, pk, foxo1a, g6pase, and pepck) and lipid metabolism-related genes (acly, fas, and cpt1a) compared to the DT strain (P < 0.05). Overall, this study revealed distinct regulation patterns of glucolipid metabolism in the gibel carp with different genotype under acute hypoxia/reoxygenation.

An 8-weeks growth trial was conducted to evaluate the effects of dietary protein levels mainly based on cottonseed protein concentrate (CPC) meal on growth performance, protein metabolism, liver health and intestinal microbiota of largemouth bass (Micropterus salmoides) juveniles. Five isolipidic (100 g/kg) diets were prepared with protein levels ranging from 400 to 560 g/kg, with CPC of 155 g/kg, 214 g/kg, 272 g/kg, 330 g/kg, 390 g/kg to obtain five experimental diets with gradient protein levels (399.9 g/kg, 428.0 g/kg, 462.8 g/kg, 503.5 g/kg and 541.5 g/kg, respectively (CPC1, CPC2, CPC3, CPC4 and CPC5)). 300 fish (initial body weight: 14.71 ± 0.50 g) were randomly assigned into 15 tanks (3 tanks per diet). The results showed that, the fish of CPC5 group had the highest specific growth rate (SGR), weight gain (WG) and feed efficiency (FE) (P < 0.05). Increased dietary protein up-regulated most liver key genes of mTOR pathway (akt, tor, s6k, 4ebp1, s6) while down-regulated atf4 at medium dietary protein (P < 0.05). The expression of fas was down-regulated with increased dietary protein, while dgat1 was higher at CPC5 group (P < 0.05). The genes related to lipolysis were up-regulated with increased dietary protein (P < 0.05). The key genes of apoptosis including bcl2, casp9, casp3 (apoptosis) oxidative stress and endoplasmic reticulum stress were significantly up-regulated at high dietary protein (P < 0.05), which reduced the antioxidant and anti-stress capacity of the liver. Dietary 462.8 g/kg protein could maintain the normal composition and metabolic function of intestinal microbiota. In summary, dietary protein requirement using CPC as main protein source was estimated to be 463 g/kg to 510 g/kg for liver health or best growth of largemouth bass juveniles.

High-starch diets may lead to growth retardation, liver damage and lipid accumulation in fish. Although mangiferin (MGF) can regulate triglyceride metabolism and protect liver health in mammals, studies on its role in fish are limited. The largemouth bass (Micropterus salmoides) were fed four different groups of diets, including a control diet (NCD), a high-starch diet (HSD), a high-starch diet supplemented with 100 mg/kg MGF (100 MGF) and a high-starch diet supplemented with 500 mg/kg MGF (500 MGF). After 8 weeks of feeding, weight gain and specific growth rate were significantly higher in the 500 MGF group than in the HSD group. Feeding rate was significantly higher in the 100 MGF group than in the HSD group. Feed conversion ratio was significantly higher in the 100 MGF group than in the HSD group. MGF reduced HSI, ALT, AST and liver vacuolization, compared with HSD group. In addition, MGF significantly reduced plasma GLU and TG levels and increased plasma HDL levels in largemouth bass. Compared to the HSD group, MGF significantly reduced TG levels in the liver, as well as reduced hepatic lipid droplet area. MGF significantly increased the relative expressions of glycolysis-related gene (pfk1), pentose phosphate pathway-related genes (g6pd, pgd and tktb) and mitochondrial oxidative phosphorylation-related gene (ndufa2, sdhb, sdhaf3, sdhaf4 and cox4). MGF significantly decreased the relative expressions of gluconeogenesis-related gene (pepck and g6pc). MGF significantly decreased the transcriptional levels of key relative expressions of triglyceride metabolism (srebf1), fatty acid synthesis-related genes (acc1, fasn and scd1) and triglyceride synthesis-related genes (gpat2, agpat2, agpat3, agpat5, dgat1a and dgat2). MGF significantly increased the relative expressions of triglyceride catabolism-related genes (pnpla2 and lipeb). The results indicated that MGF reduced lipid accumulation and alleviated high starch diet-induced liver damage by regulating triglyceride metabolism in largemouth bass.

A high carbohydrate diet (HCD) induced excessive hepatic de novo lipogenesis, which caused metabolic disorder and impaired the health of fish species. Betulinic acid (BA) has been applied to ameliorate fatty liver and anti-inflammatory in mammals. Here, we investigated the effects of dietary BA supplementation on HCD-induced hepatic de novo lipogenesis and liver health in channel catfish (Ictalurus punctatus). The catfish were fed with three diets: NCD (18 % carbohydrate), HCD (36 % carbohydrate), HCD+BA (36 % carbohydrate with 150 mg/kg BA). After an 8-week feeding trial, we found that dietary BA decreased hepatosomatic index (HSI) and condition factor (CF) without affecting the growth of channel catfish fed HCD. Dietary BA significantly reduced the HCD-induced excessive lipid accumulation (oil red O area, TG content, and de novo lipogenesis gene expression, P < 0.05). Moreover, we found that dietary BA prevented hepatic lipid accumulation via activating phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and inhibiting sterol regulatory element-binding protein 1 (SREBP1) (P < 0.05) in liver of channel catfish fed HCD. Besides, we also found that dietary BA significantly prevented HCD-induced liver damage, as confirmed by liver H&E staining, reduced inflammation biomarkers (ALT, AST, hydroxyproline, α-sma and tgf-1β), downregulated expression of ER stress-related genes (eif2a, bip, atf4, xbp1) (P < 0.05). Overall, the present study indicated that dietary BA inclusion attenuated hepatic de novo lipogenesis, improved liver inflammation and reduced ER stress in channel catfish fed HCD.

In this study, optimized multivitamin premix (OVP) was added to three kinds of different protein quality feeds (by decreasing dietary protein levels from 50% to 45% and replacing marine fish meal with terrestrial proteins) to investigate the effects of OVP on dietary protein quality-induced fatty liver in largemouth bass. Lysine (Lys) and methionine (Met) were supplied to ensure a consistent level of these two limiting amino acids. The results showed that decreased dietary protein quality did not affect the FBW and SGR of largemouth bass (P>0.05), but improved protein efficiency (P

Background: Tetrahydrobiopterin (BH4) deficiency is a rare cause of hyperphenylalaninemia (HPA). The incidence of this condition varies based on region and ethnicity. In the early stages, patients typically do not exhibit any symptoms, and HPA is identified only through newborn screening for diseases. It is important to distinguish BH4 deficiency from phenylketonuria (PKU, MIM # 261600). Timely diagnosis and treatment of BH4 deficiency are crucial for the prognosis of patients. Case presentation: We present two rare cases of Chinese Tibetan children with BH4D, diagnosed through biochemical tests and genetic sequencing. Case 1 is a male infant, 2 months old, with a newborn screening (NBS) Phe level of 1212 μmol/L (reference range T (p.Pro87Ser), rs104894276, ClinVar variation ID: 480]. The patient was treated with a Phe-reduced diet and oral sapropterin, madopar and is currently 3 years and 4 months old, showing mild global developmental delay. Case 2 is a 40-day-old female infant with a Phe level of 2442.11 μmol/L and dihydropteridine reductase (DHPR) activity of 0.84 nmol/(min. 5 mm disc) (reference range: 1.02–3.35 nmol/min.5 mm disc. Gene sequencing revealed a compound heterozygous genotype [NM_000320.3(QDPR): c.68G > A (p.Gly23Asp), rs104893863, ClinVar Variation ID: 490] and [NM_000320.3(QDPR) c.419C > A (p. Ala140Asp), ClinVar ID: 2444501]. The patient was treated with a Phe-reduced diet and oral madopar, 5-hydroxytryptophan. At the age of 1 year, she exhibited severe global developmental delay with seizures. Conclusion: We identified and treated two cases of BH4D in Tibetan populations in China, marking the first confirmed instances. Our report emphasizes the significance of conducting differential diagnosis tests for BH4D.

Starch is a common source of carbohydrates in aqua feed. High-starch diet can cause hepatic injury and lipid accumulation in fish. Mangiferin (MGF) can regulate lipid metabolism and protect the liver, but there is limited research on its effects in fish. In the present study, we investigated whether MGF could ameliorate high-starch-induced hepatic damage and lipid accumulation in channel catfish. The channel catfish (Ictalurus punctatus) were fed one of four experimental diets for eight weeks: a control diet (NCD), a high-starch diet (HCD), an HCD supplemented with 100 mg/kg MGF (100 MGF), and an HCD supplemented with 500 mg/kg MGF (500 MGF). The results demonstrated that the weight gain rate (WGR) (p = 0.031), specific growth rate (SGR) (p = 0.039), and feed conversion efficiency (FCE) (p = 0.040) of the 500 MGF group were significantly higher than those of the NCD group. MGF supplementation alleviated liver damage and improved antioxidant capacity (T-AOC) compared to those of the HCD group (p = 0.000). In addition, dietary MGF significantly reduced plasma glucose (GLU) (p = 0.000), triglyceride (TG) (p= 0.001), and low-density lipoprotein cholesterol (LDL) (p = 0.000) levels. It is noteworthy that MGF significantly reduced the plasma total cholesterol (TC) levels (p = 0.000) and liver TC levels (p = 0.005) of channel catfish. Dietary MGF improves cholesterol homeostasis by decreasing the expression of genes that are involved in cholesterol synthesis and transport (hmgcr, sqle, srebf2, sp1, and ldlr) and increasing the expression of genes that are involved in cholesterol catabolism (cyp7a1). Among them, the largest fold decrease in squalene epoxidase (sqle) expression levels was observed in the 100 MGF or 500 MGF groups compared with the HCD group, with a significant decrease of 3.64-fold or 2.20-fold (p = 0.008). And the 100 MGF or 500 MGF group had significantly decreased (by 1.67-fold or 1.94-fold) Sqle protein levels compared to those of the HCD group (p = 0.000). In primary channel catfish hepatocytes, MGF significantly down-regulated the expression of sqle (p = 0.030) and reduced cholesterol levels (p = 0.000). In NCTC 1469 cells, MGF significantly down-regulated the expression of sqle (p = 0.000) and reduced cholesterol levels (p = 0.024). In conclusion, MGF effectively inhibits sqle expression and reduces cholesterol accumulation. The current study shows how MGF supplementation regulates the metabolism and accumulation of cholesterol in channel catfish, providing a theoretical basis for the use of MGF as a dietary supplement in aquaculture.

Since the aquaculture industry is currently observing a deterioration in the flesh quality of farmed fish, the use of nutrients as additives to improve the flesh quality of farmed fish species is a viable strategy. The aim of this study was to investigate the effect of dietary D-ribose (RI) on the nutritional value, texture and flavour of gibel carp (Carassius auratus gibelio). Four diets were formulated containing exogenous RI at 4 gradient levels: 0 (Control), 0.15% (0.15RI), 0.30% (0.30RI) and 0.45% (0.45RI). A total of 240 fish (150 ± 0.31 g) were randomly distributed into 12 fibreglass tanks (150 L per tank). Triplicate tanks were randomly assigned to each diet. The feeding trial was carried out in an indoor recirculating aquaculture system for 60 d. After the feeding trial, the muscle and liver of gibel carp were analysed. The results showed that RI supplementation did not result in any negative impact on the growth performance and 0.30RI supplementation significantly increased the whole-body protein content compared to the control group. The contents of collagen and glycogen in muscle were enhanced by RI supplementation. The alterations in the flesh indicated that RI supplementation improved the texture of the flesh in terms of its water-holding capacity and hardness, therefore improving the taste. Dietary RI facilitated the deposition of amino acids and fatty acids in the muscle that contributed to the meaty taste and nutritional value. Furthermore, a combination of metabolomics and expression of key genes in liver and muscle revealed that 0.30RI activated the purine metabolism pathways by supplementing the substrate for nucleotide synthesis and thereby promoting the deposition of flavour substance in flesh. This study offers a new approach for providing healthy, nutritious and flavourful aquatic products.

The trial was conducted to investigate the effects of the replacement of dietary fishmeal (FM) by the blend of Tenebrio molitor meal (TMM), Chlorella meal (CM), Clostridium autoethanogenum protein (CAP), cottonseed protein concentrate (CPC) on growth, protein utilization and intestinal health of gibel carp (Carassius gibelio, CAS Ⅴ). The FM-based diet was used as the control, and the blended proteins (TMM: CM: CAP: CPC) at ratios of 1 : 1:8 : 2 (BLEND A), 1 : 1:6 : 4 (BLEND B), and 1 : 1:4 : 6 (BLEND C) were used to replace FM at three levels (33%, 67%, 100%), respectively. The results showed that, compared to the control group, growth performance increased significantly when dietary FM was fully replaced by BLEND B (P

Glutamate (Glu) plays important physiological roles in protein synthesis and muscle flesh quality. Despite existing studies on the effects of Glu on fish muscle quality, the underlying mechanism thereof remains unclear. To illustrate the effects of Glu on the flesh quality of triploid crucian carp, fish were fed a diet with added 3.2% Glu (no additional Glu was used as a control). Results showed that dietary Glu promoted the expression levels of genes related to the growth of muscle fibers, thereby promoting the development of the sarcolemma and regulating the hardness and springiness of muscle. Moreover, dietary Glu improved muscle protein deposition via AMPK/mTOR signaling pathway activation. Besides, aspartate, Glu, and inosine monophosphate (IMP) levels in muscle were markedly enhanced by dietary Glu supplementation. In summary, Glu improves flesh quality and growth of triploid crucian carp by regulating protein synthesis, protein retention and flavor compound deposition.

Previous nutritional studies have shown that intermediate metabolism in early fish development is highly plastic, and thus we hypothesized that there may be an early programming effect of a hyperglucidic diet on carbohydrate utilization in gibel carp. To test our hypothesis, gibel carp CAS Ⅴ (mean body weight: 0.10 g) were fed a high-carbohydrate/low protein (HC/LP) or low carbohydrate/high protein (LC/HP) diet for three weeks, and then were fed with normal feed for 12 weeks and a hyperglucidic diet for one week. We found that early HC/LP stimulus inhibited growth performance but altered the expression of glucose metabolism genes. After long-term feeding on the normal diet, the effects of early HC/LP stimulus were eliminated; these involved plasma metabolites, hepatic cholesterol, glycogen and triglyceride content, and glucose and lipid metabolism. However, the early HC stimulus group showed a better ability to maintain plasma glucose hemostasis when again given the HC diet. The capacity of carbohydrate and lipid metabolism in juvenile gibel carp was improved in the early HC diet group, as indicated by upregulated expression of genes related to glycolysis, lipid transport (gk, akt, srebp1, acc, fas, hsl, and acly) and downregulated expression of genes involved in gluconeogenesis (fbpase). Moreover, the early HC diet significantly upregulated AKT protein expression levels. The DNA methylation levels of akt in the HC/LP group were significantly lower than those in the LC/HP group. Overall, the study suggests that early HC stimulus in juvenile gibel carp can result in better carbohydrate utilization through DNA methylation of critical elements in the insulin signaling pathway.

An 88-day feeding trial was conducted to evaluate the effects of dietary inosine 5′-monophosphate (5′-IMP) on the growth performance and salinity and oxidative stress resistance in the juvenile gibel carp CAS III (Carassius auratus gibelio; initial body weight: 7.48 g). Four isonitrogenous and isoenergetic diets containing exogenous 5′-IMP were formulated. P1, P2, P3 and P4 were diets containing 5′-IMP at four concentrations (0, 1, 2 and 4 g kg−1). The four diets were randomly allotted to triplicate tanks in a recirculating system. After the feeding trial, six fish per tank were netted randomly and placed into 12‰ saline water to test their response to salinity stress. The results indicated that the feed conversion rate was enhanced by dietary supplementation with 5′-IMP. The appetite, plasma neuropeptide Y level and feeding rate of the P3 group were lower than those in the control treatment group. Dietary supplementation with 5′-IMP improved the osmoregulatory adaptation of gibel carp under acute salinity stress. Six hours after the salinity stress treatment, in the dietary 5′-IMP treatment group, the plasma cortisol and K+ concentrations were lower and the Na+/K+-ATPase activity was greater than that in the control group. Dietary supplementation with 5′-IMP promoted the expression of the glucocorticoid receptors NKA-α1b and NKCC and retarded the expression of Hsp70 in P4-treated gill filaments and kidneys. Dietary supplementation with 5′-IMP resulted in a stable oxidative-stress-resistant phenotype characterized by increased levels of cellular antioxidants, including SOD, catalase, glutathione peroxidase, glutathione reductase and MPO. The above results of the current study demonstrate that supplementation of 5′-IMP can promote feed utilization and have positive influences on the salinity and oxidative stress resistance of gibel carp.

Chlorella meal is a potential protein source for aquafeeds. However, the physiological response of carnivorous fish fed Chlorella meal remains elusive. This study evaluated the effects of replacing dietary fish meal with Chlorella meal on growth performance, pigmentation, and liver health in largemouth bass. Five diets were formulated to replace dietary fish meal of 0% (C0, control), 25% (C25), 50% (C50), 75% (C75), and 100% (C100) with Chlorella meal, respectively. Total 300 fish (17.6 ± 0.03 g) were randomly assigned to 15 tanks (3 tanks/group). Fish were fed the experimental diet twice daily for 8 weeks. The increased dietary Chlorella meal quadratically influenced the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), and feed intake (FI), which were significantly lower in the C100 group than in the other groups (P

Several epidemiological studies suggest a correlation between eating time and obesity. Night eating syndrome characterized by a time-delayed eating pattern is positively associated with obesity in humans as well as in experimental animals. Here, we show that oil intake at night significantly makes more fat than that at day in wild-type mice, and circadian Period 1 (Per1) contributes to this day–night difference. Per1-knockout mice are protected from high-fat diet–induced obesity, which is accompanied by a reduction in the size of the bile acid pool, and the oral administration of bile acids restores fat absorption and accumulation. We identify that PER1 directly binds to the major hepatic enzymes involved in bile acid synthesis such as cholesterol 7alpha-hydroxylase and sterol 12alpha-hydroxylase. A biosynthesis rhythm of bile acids is accompanied by the activity and instability of bile acid synthases with PER1/PKA-mediated phosphorylation pathways. Both fasting and high fat stress enhance Per1 expression, increasing the fat absorption and accumulation. Our findings reveal that Per1 is an energy regulator and controls daily fat absorption and accumulation. Circadian Per1 controls daily fat absorption and accumulation, suggesting Per1 is a potential candidate of a key regulator in stress response and the relevant obesity risk.

Glass frit used in conductive silver (Ag) pastes has a significant impact not only on the electrical performance but also on the long-term reliability of metallized electrodes in crystalline silicon (c-Si) solar cells. Here, we investigated the role of compositional changes on the metallization process of silver pastes by adjusting the SiO _2 , ZnO, Li _2 O, or Bi _2 O _3 in lead borate glass melts, and performed damp heat (DH) tests in an acidic damp heat environment. It was found that the addition of Bi _2 O _3 resulted in a decrease in conversion efficiency (Eta) of only 6.44% after the cell was treated with dilute acetic acid. Under scanning electron microscopy (SEM), it was observed that the cell with this glass frit had minimal changes in the microstructure of its silver-silicon contacts and silver electrodes. This finding helps to improve the performance and stability of solar cells in harsh environments.

The active ingredients extracted from yeast are important for regulating animal health. The aim of the current research was to explore the impacts of dietary yeast glycoprotein (YG) on the growth performance, intestinal morphology, antioxidant capacity, immunity and disease resistance of largemouth bass (Micropterus salmoides). A total of 375 juvenile fish (6.00 ± 0.03 g) were allocated into 15 fiberglass tanks. Triplicate tanks were assigned to each diet. The dietary YG inclusion was as follows: the first group was given a high fishmeal diet (40% fishmeal, 0% YG) (FM) and the second group was given a low fishmeal diet (30% fishmeal and 15% soybean meal, 0% YG) (LFM). The fish in the third, fourth and fifth groups were fed the LFM diet supplemented with 0.5% (LFM+YG0.5), 1.0% (LFM+YG1.0) and 2.0% (LFM+YG2.0) YG, respectively. After a 60- day feeding trial, a challenge test using A. hydrophila was carried out. The results showed that the final body weight (FBW) and weight gain rate (WGR) in the LFM+YG2.0 group were significantly higher than those in the LFM group and were no significantly different from those in the FM group. This may be partially related to the activation of the target of rapamycin (TOR) signaling pathway. Dietary YG supplementation enhanced intestinal physical barriers by upregulating the intestinal tight junction protein related genes (claudin1, occludin and zo2) and improving the structural integrity of the gut, which may be partially associated with AMPK signaling pathway. Moreover, dietary YG increased the antioxidant capacity in the gut, upregulated intestinal anti-inflammatory factors (il-10, il1-1β and tgf-β) and downregulated proinflammatory factors (il-1β and il-8), which may be partially related to the Nrf2/Keap1 signaling pathways. The results of the challenge test indicated that dietary supplementation with 0.5 or 1.0% YG can increase the disease tolerance of largemouth bass against A. hydrophila. In conclusion, the present results indicated that dietary supplementation with YG promotes the growth performance, intestinal immunity, physical barriers and antioxidant capacity of largemouth bass. In addition, 1.0% of dietary YG is recommended for largemouth bass based on the present results.

IntroductionResveratrol (RES) is a polyphenol organic compound with antioxidant and anti-inflammatory properties. This study aimed to determine whether and how RES can alleviate liver injury in lipopolysaccharide (LPS)-induced gibel carp.MethodsGibel carp were fed a diet with or without RES and were cultured for 8 weeks, followed by LPS injection.Results and discussionThe results suggested that RES attenuated the resulting oxidative stress and inflammation by activating the Nrf2/Keap1 pathway and inhibiting the NF-κB pathway, as confirmed by changes in oxidative stress, inflammation-related gene expression, and antioxidant enzyme activity. Furthermore, RES cleared damaged mitochondria and enhanced mitochondrial biogenesis to mitigate reactive oxygen species (ROS) accumulation by upregulating the SIRT1/PGC-1α and PINK1/Parkin pathways and reducing p62 expression. Overall, RES alleviated LPS-induced oxidative stress and inflammation in gibel carp through mitochondria-related mechanisms.

The effects of dietary yeast hydrolysate on the growth performance, gut health, and digestion of juvenile yellow catfish were evaluated throughout a 62-day feeding trial. Isonitrogenous and isoenergetic experimental diets were prepared. The positive control fishmeal (FM) diet contained 40 % FM. The negative control plant protein diet (PM group) contained 18 % soybean meal (SBM) and 18 % rapeseed meal (RSM). In other two test diets, 1 % and 5 % of yeast hydrolysate (1 % YH and 5 % YH group) were used to replace SBM and RSM (1:1) of PM group, respectively. The results showed no significant differences in the growth performance of yellow catfish among all groups. However, daily food intake was significantly increased in 5 % YH compared with the control PM. Besides, the apparent digestibility coefficient (ADC) of dry matter improved in 1 % YH, compared with FM. And the YH groups had significantly higher total EAA concentrations in plasma than PM group. The 1 %−5 % YH supplement in plant protein diet could improve the length of gut villi and density of distal intestinal microvilli, and enhance the antioxidant capacity of mid intestine and distal intestine. Compared with PM, YH groups increased the digestive capacity of proximal intestine and mid intestine. It is concluded that 1 %−5 % of dietary yeast hydrolysate improved intestine health, food consumption and absorptive ability of yellow catfish.

To meet the consumer demand for high-quality flesh sources, this study investigated the impacts of exercise training (ET) combined with a high-fat diet (HFD) on flesh quality. The results showed that HFD increased muscular fat content but reduced hardness, flexibility and adhesiveness. ET decreased fat content but increased flesh water holding capacity, hardness and stickiness. In terms of flavour, ET decreased the umami and sweet amino acid contents, which were restored when concomitantly feeding the HFD. Metabolomics further revealed that ET and HFD mainly affect the alanine, aspartate and glutamate metabolism, the citrate cycle and purine metabolism. The E-nose and volatile metabolomics analysis demonstrated that the combination of ET and HFD improved the aroma of flesh by enhancing the content of key flavour compounds within flesh such as hexadecenoic acid, ethyl ester and methyl stearate. This research provides a new strategy for improving the flesh quality of cultured fish.

Ammonia is recognized as an environmental stressor for fish. As resveratrol (RES) has anti-inflammatory and antioxidant properties, we hypothesized that RES could attenuate the response to ammonia exposure in gibel carp. Therefore, gibel carp were fed a diet containing RES for eight weeks, followed by acute ammonia stimulation. Stress induced by acute ammonia exposure could be ameliorated by RES, manifested by down-regulated plasma glucose, and up-regulated C3 and IgM levels. Furthermore, decreased AST and LDH; enhanced T-AOC, SOD, and GPx in the liver; and reduced damage to gill and liver tissues indicated that RES attenuated oxidative and tissue damage induced by ammonia exposure. Moreover, RES activated the Nrf2/HO-1 pathway and up-regulated the expression of several antioxidant genes. RES enhanced anti-inflammatory activity as reflected by activation of the NF-κB pathway, down-regulated the expression of pro-inflammatory cytokines (nfκb, tnf-α, and il-1β), and up-regulated the expression of anti-inflammatory cytokines (il-4 and il-10). In terms of mitochondrial function, RES up-regulated protein levels of p-AMPK, SIRT1, and PGC-1α; inhibited mitochondrial fission; promoted mitochondrial fusion and biogenesis-related gene expression. Overall, the results suggest that RES mediated the Nrf2/HO-1, NF-κB, and AMPK/SIRT1/PGC-1α pathways to attenuate oxidative stress, inflammation, and mitochondrial dysfunction induced by ammonia in gibel carp.

Excessive carbohydrate intake leads to metabolic disorders in fish. However, few literatures have reported the appropriate carbohydrate level for zebrafish, and the metabolic response to dietary carbohydrate remains largely unknown in zebrafish. This study assessed the responses of zebrafish and zebrafish liver cell line (ZFL) to different carbohydrate levels. In vivo results showed that ≥30% dietary dextrin levels significantly increased the plasma glucose content, activated the expression of hepatic glycolysis-related genes, and inhibited the expression of hepatic gluconeogenesis-related genes in zebrafish. Oil red O staining, triglyceride content, and Hematoxylin-Eosin staining results showed that dietary dextrin levels of ≥30% significantly increased lipid accumulation and liver damage, as well as processes related to glycolipid metabolism and inflammation in zebrafish. In ZFL, the transcription factor sterol regulatory element binding protein-1c signal intensity, 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY 493/503) signal intensity, and triglyceride content were also significantly increased when incubated in high glucose, along with abnormal glycolipid metabolism and increased inflammation-related genes. In conclusion, we demonstrated that the maximum dietary carbohydrate level in adult zebrafish should be less than 30%. Excess dietary carbohydrates (30%–50%) caused hepatic steatosis and damage to zebrafish, similar to that seen in aquaculture species. Thus, this study assessed responses to different carbohydrate levels in zebrafish and illustrated that zebrafish is an optimal model for investigating glucose metabolism in some aquatic animals.

To assess the effect of dietary selenium (Se) sources on the meat quality and antioxidant capacity of yellow catfish (Pelteobagrus fulvidraco), sodium selenite (Na2SeO3), Se yeast, and selenium-enriched Spirulina platensis (Se–SP) were supplemented in the control diet at 0.30 mg Se/kg feed to formulate four diets. The experimental period lasted 50 days. The results showed that Se levels in the plasma, liver, muscle, and whole body were significantly increased by dietary Se yeast supplementation (P0.05). The three types of Se all increased the firmness and decreased the fracturability of the muscles (P

The present study investigated the sequential regulation signals of high-carbohydrate diet (HCD)-induced hepatic lipid deposition in gibel carp (Carassius gibelio). Two isonitrogenous and isolipidic diets, containing 25% (normal carbohydrate diet, NCD) and 45% (HCD) corn starch, were formulated to feed gibel carp (14.82 ± 0.04 g) for 8 weeks. The experimental fish were sampled at 2nd, 4th, 6th, and 8th week. In HCD group, the hyperlipidemia and significant hepatic lipid deposition (oil red O area and triglyceride content) was found at 4th, 6th, and 8th week, while the significant hyperglycemia was found at 2nd, 4th, and 8th week, compared to NCD group (P

To investigate the effects of different dietary protein sources on the reproductive performance of female broodstock, yellow catfish (Pelteobagrus fulvidraco) were fed with three experimental diets using fishmeal (FM), soybean meal (SBM), and rapeseed meal (RSM) as main protein sources, respectively. Females (initial weight: 64.56±0.45 g) were distributed into 9 net cages for feeding trial. Results indicated that 30% dietary SBM improved the reproductive performance for higher gonadosomatic index (GSI), relative fecundity, total egg production, egg diameter, and hatching rate. In addition, SBM and RSM diets resulted in higher estradiol (E2), vitellogenin (VTG), luteinizing hormones (LH), and lower follicle-stimulating hormone (FSH) and testosterone (T) in plasma (P

An 8-week feeding trial was conducted to evaluate the application of common carbohydrate sources, cornstarch (CS), wheat starch (WS), and wheat flour (WF), to different gibel carp genotypes, Dongting, CASIII, and CASV. The results of the growth and physical responses were analysed by data visualization and unsupervised machine learning. As revealed by a self-organizing map (SOM) and the cluster of growth and biochemical indicators, CASV had superior growth and feed utilization and better regulation of postprandial glucose, followed by CASIII, while Dongting showed a high level of plasma glucose with poor growth performance. CS, WS, and WF were differently utilized by the gibel carp, and WF was associated with greater zootechnical performance based on higher specific growth rate (SGR), feed efficiency (FE), protein retention efficiency (PRE), and lipid retention efficiency (LRE), induced hepatic lipogenesis, increased liver lipids, and enhanced muscle glycogen. Spearman’s correlation analysis of the physiological responses indicated that plasma glucose had a significantly negative correlation with growth, feed utilization, glycogen storage, and plasma cholesterol level, and it was positively related to liver fat content in gibel carp. Transcriptional variabilities were observed: CASIII showed increased expression of pklr, which is involved in hepatic glycolysis, and pck and g6p, which are involved in gluconeogenesis. Interestingly, Dongting showed upregulation of genes involved in glycolysis and fatty acid oxidation in muscle. Furthermore, there were numerous interactions between carbohydrate sources and strains for growth, metabolites, and transcriptional control, confirming the existence of genetic polymorphisms in carbohydrate use in gibel carp. Globally, CASV showed relatively better growth and carbohydrate utilization, and wheat flour seemed to be more efficiently utilized by gibel carp.

Eriocheir sinensis larva normally experiences 11 stages. The reduced abdomen folded beneath the thorax is the most prominent characteristic of morphological alteration from megalopa to juvenile crab. Up to date, the molecular mechanisms of brachyurization remain a mystery. Here, transcriptome library, digital gene expression (DGE) libraries and proteome libraries at two developmental stages [the megalopa stage of E. sinensis (stage M) and the first stage of juvenile crab (stage J1)] of the Chinese mitten crab larva were constructed for RNA sequencing and iTRAQ approaches followed by bioinformatics analysis, respectively. In total, 1106 genes and 871 proteins were differentially expressed between the stage M and stage J1. Moreover, several important pathways were identified, including biosynthesis of secondary metabolites, metabolic pathways, focal adhesion, and some disease pathways. Besides, muscle contraction, oxidative phosphorylation, calcium signaling, PI3K-Akt, DNA replication pathway, and integrin signaling pathway also had important functions in brachyurization process. Furthermore, the components, actin, actin-related protein, collagens, filamin-A/B, laminin, integrins, paxillin, and fibronectin had up-regulated expression levels in M stage compared to J1 stage.

Microalgae have beneficial effects on the performance of fish as additives and they are becoming a promising alternative to fishmeal as macronutrient ingredients. However, the impact on the fish intestinal microbiome and the function, caused by microalgae as protein sources in diets, remains unclear. This study aimed to determine the composition and potential function of the intestinal microbial community of largemouth bass (Micropterus salmoides) fed diets at five replacement levels (0, 25, 50, 75 and 100%) of fishmeal by Chlorella meal in a basal diet (400 g kg−1) after 8 weeks. The results showed significant decreases in unique amplicon sequence variants in the intestine at the higher levels of fishmeal replacement. At 50% of fishmeal replacement, dietary inclusions of Chlorella meal had no impact on species richness and Shannon diversity and the community structure of the intestinal microbiota. However, high levels of fishmeal replacement (75 and 100%) significantly induced intestinal community disturbance and diversity loss in largemouth bass. Responding to the high fishmeal replacement level, the dominant genus Cetobacterium and Pleslomonas sharply increased and several taxa from Lactobacillus decreased significantly. Functional data predicted by PICRUSt revealed that nutrition-related metabolism was dominant in the intestinal microbiota of fish fed all the five diets, although some potential functions, particularly amino acid and lipid metabolisms, and energy metabolism, were upregulated firstly, and then downregulated in fish fed diets with the increase of dietary Chlorella meal. Meanwhile, certain pathways were not enriched in intestinal microbiome until up to 75% of fishmeal replacement, such as carbohydrate metabolism, and cofactors and vitamins metabolism. To conclude, this study reveals that fishmeal replacement (50%) by Chlorella meal at the level of 237 g kg−1 in diets is feasible for largemouth bass without impairing the microbiome structure and the metabolism function, providing an alternative strategy for evaluating the possibility of fishmeal replacement by microalgae in aquafeeds.

High carbohydrate diet (HCD) causes metabolism disorder and intestinal damages in aquaculture fish. Berberine has been applied to improve obesity, diabetes and NAFLD. However, whether berberine contributes to the alleviation of HCD-induced intestinal damages in aquaculture fish is still unclear. Here we investigated the effects and mechanism of berberine on HCD-induced intestinal damages in largemouth bass (Micropterus salmoides). We found dietary berberine (50 mg/kg) improved the physical indexes (VSI and HSI) without affecting the growth performance and survival rate of largemouth bass. Importantly, the results showed that dietary berberine reduced the HCD-induced tissue damages and repaired the barrier in the intestine of largemouth bass. We observed dietary berberine significantly suppressed HCD-induced intestinal apoptosis rate (from 31.21 to 8.35%) and the activity level of Caspase3/9 (P < 0.05) by alleviating the inflammation (il1β, il8, tgfβ, and IL-6, P < 0.05) and ER stress (atf6, xbp1, perk, eif2α, chopa, chopb, and BIP, P < 0.05) in largemouth bass. Further results showed that dietary berberine declined the HCD-induced excessive lipogenesis (oil red O area, TG content, acaca, fasn, scd, pparγ, and srebp1, P < 0.05) and promoted the lipolysis (hsl, lpl, cpt1a, and cpt2, P < 0.05) via activating adenosine monophosphate-activated protein kinase (AMPK, P < 0.05) and inhibiting sterol regulatory element-binding protein 1 (SREBP1, P < 0.05) in the intestine of largemouth bass. Besides, we also found that dietary berberine significantly promoted the hepatic lipid catabolism (hsl, lpl, cpt1a, and cpt2, P < 0.05) and glycolysis (pk and ira, P < 0.05) to reduce the systematic lipid deposition in largemouth bass fed with HCD. Therefore, we elucidated that 50 mg/kg dietary berberine alleviated HCD-induced intestinal damages and improved AMPK/SREBP1-mediated lipid metabolism in largemouth bass, and evaluated the feasibility for berberine as an aquafeed additive to enhance the intestinal function of aquaculture species.

Long-term high stocking density often brings negative effects such as decreased body weight, decreased immunity, and increased mortality to cultured fish, while the effects of short-term stocking are relatively less studied. In this experiment, we characterized spatial and temporal gene expression in black porgy (Acanthopagrus schlegelii) liver by establishing two stocking density groups—high (H: 26.5 kg/m3) and low (L: 2.95 kg/m3)—and conducting transcriptome sequencing before collecting liver samples at two time points: 6 h (AL and AH) and 60 d (CL and CH) into the culture trial. There were 648 and 550 differentially expressed genes (DEGs) in the AL-vs-AH and CL-vs-CH groups, respectively. The DEGs in the AL-vs-AH group were significantly enriched in steroid biosynthesis, terpenoid backbone biosynthesis, the PPAR signaling pathway, proteasome, aminoacyl-tRNA biosynthesis, and ribosome biogenesis in eukaryotes. The DEGs in the CL-vs-CH group were more significantly enriched in lipid metabolism-related pathways, such as the PPAR signaling pathway, fatty acid metabolism, and cholesterol metabolism. In addition, immune-related pathways such as the phagosome and complement and coagulation cascades were also enriched in the CL-vs-CH group. The expression changes concerning the DEGs in each group were further analyzed. The DEGs related to steroid synthesis, protein synthesis, and the degradation pathways were down-regulated, but immune-related genes were generally up-regulated in the AH group. The DEGs related to lipid synthesis were significantly up-regulated in the CH group, but the DEGs related to lipid consumption and utilization were down-regulated. The expression of immune-related DEGs was also negatively affected in the CH group. These results suggest that acute and chronic crowding stress affects lipid metabolism and immune regulation in the liver of black porgy. Acute stress particularly affected hepatic protein metabolism, while chronic stress showed more effects on hepatic lipid metabolism. The results of this study provide a theoretical basis for understanding the effects of high stocking densities upon black porgy and may also provide a reference for crowding stress regulation studies in other fish species.

Inosine monophosphate (IMP) improves the flesh quality of livestock and poultry, but studies about its effect on fishes are limited. The aim of the present study was to investigate the effect of exogenous IMP on the liver health and flesh quality of gibel carp (Carassius auratus gibelio). The results showed that IMP supplementation alleviated hepatic lipid deposition by increasing the AMP/ATP ratio and activating the AMPK signaling pathway then decreased inflammatory cytokine expression levels. Additionally, IMP increased the intramuscular fat content. Metabolomic analysis of meat revealed that the IMP, adenosine monophosphate (AMP), guanosine, inosine and purine metabolism pathways were involved in the improvements in fish meat quality, composition and taste that resulted from IMP supplementation. Our study provides a relatively comprehensive assessment of the effect of exogenous IMP on the liver metabolism and flesh quality of farmed fish. The results provide an effective food supplementation strategy for cultured fish.

To investigate the physiological responses to different energy sources under feeding restriction in fish, gibel carp were fed a high lipid, low carbohydrate diet (HL diet, 12% lipid, 16% carbohydrate) or a high carbohydrate, low lipid diet (HC diet, 34% carbohydrate, 4% lipid) to satiation or 70% satiation (restriction) for 56 d; then, growth performance, nutrient metabolism, endoplasmic reticulum (ER) stress, autophagy, and apoptosis were determined. Fish that were fed the HL diet had higher final body weight, specific growth rate, and feed efficiency, lower phosphorylation levels of AKT and mTOR proteins and lower mRNA levels of gk than the HC group. When fed to 70% satiation, fish had lower feed intake, feeding rate, final body weight, and specific growth rate, and lower plasma glucose and nonesterified fatty acid levels. Feeding restriction induced the transcript level of gk and suppressed the mRNA level of acly, acc, fas. There were no significant differences in ER stress, autophagy and apoptosis between feeding levels or diets. Interactions between feeding level and diet were observed in plasma triglyceride level and the gene expression levels of fbpase and srebp1. Thus, gibel carp utilized HL diet better than HC diet, which was unalerted by feeding restriction.

Inflammation is an energy-intensive process and the liver is a key organ in energy regulation. Since the intestine and liver exchange nutrients and metabolites, enteritis can affect the liver. To investigate the correlation between enteritis and liver metabolism, we developed an intestinal inflammation model with concentration-dependent 2,4,6-trinitrobenzene sulfonic acid (TNBS) in gibel carp (Carassius gibelio). The results showed the dysregulation of intestinal tight junction, increased permeability of the gut barrier, and apoptosis of epithelial cells during the development of enteritis. The liver metabolome was analyzed by LC-MS and the live respiration was determined using Oxygraph-2k. The results showed that glycolysis, the TCA cycle and pyrimidine metabolism were affected by intestinal inflammation. In particular, the activity of hepatic mitochondrial respiratory chain complex I was significantly increased. Structure and abundance changes of gut microbiota were analyzed by 16S rRNA sequencing analysis. Pathogenic bacteria in the intestine, as well as plasma LPS, increased significantly. Using a liver cell line, we verified that the dysfunctional metabolism of the liver is related to the dislocation of LPS. All results imply the existence of a connection between enteritis and liver metabolism in gibel carp, and the gut microbiome plays a critical role in this process.

This study was conducted to evaluate the effects of dietary protein levels on the growth, spawning, and larval quality of female yellow catfish (Pelteobagrus fulvidraco) broodstock through a six-week feeding trial. Five isoenergetic diets were formulated, and the crude protein levels were 34.4 (DP34), 38.8 (DP39), 44.2 (DP44), 49.3 (DP49), and 52.7% (DP53). The results showed that the growth and reproductive performance, including the specific growth rate (SGR), feed efficiency (FE), gonadosomatic index (GSI), and hatching rate of yellow catfish broodstock in the DP44, DP49, and DP53 groups were significantly higher than those of other groups (P

This study investigated the potential role of curcumin (CUR) in preventing oxidative stress and ferroptosis induced by ammonia exposure in gibel carp. Experimental fish (initial weight: 11.22 ± 0.10 g, n = 150) were fed diets supplemented with or without 0.5% CUR for 56 days, followed by a 24 h ammonia (32.5 mg/L) exposure. Liver damages (aspartate aminotransferase (AST), alanine aminotransferase (ALT), adenosine deaminase (ADA), and alkaline phosphatase (ALP)) and oxidative stress enzyme activities (reactive oxygen species (ROS), malondialdehyde (MDA); and the content of antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GPx)) were induced by ammonia stress. The antioxidant capacity was decreased, as indicated by inhibited gene expression of nuclear factor erythroid 2-related factor 2 (nrf2), heme oxygenase-1 (ho-1), catalase (cat), and sod. Ferroptosis was induced by ammonia stress, as suggested by upregulated mRNA levels of nuclear receptor coactivator 4 (ncoa4), transferrin receptor 1 (tfr1), and iron-responsive element-binding protein 2 (ireb2), and downregulated expression of glutathione peroxidase 4 (gpx4), ferroportin (fpn), and ferritin heavy chain 1 (fth1). In addition, both mRNA and protein levels of ferroptosis markers acyl-CoA synthetase long-chain family member 4 (ACSL4) and prostaglandin-endoperoxide synthase 2 (PTGS2) were upregulated, while cystine/glutamate antiporter (SLC7A11) was downregulated. However, liver injury and ferroptosis in fish induced by ammonia could be attenuated by CUR. Collectively, these findings demonstrate that CUR ameliorates oxidative stress and attenuates ammonia stress-induced ferroptosis. This study provides a new perspective on potential preventive strategies against ammonia stress in gibel carp by dietary CUR.

Abstract The biological clock is an endogenous biological timing system, which controls metabolic functions in almost all organs. Nutrient metabolism, substrate processing, and detoxification are circadian controlled in livers. However, how the clock genes respond to toxins and influence toxicity keeps unclear. We identified the clock gene Per1 was specifically elevated in mice exposed to toxins such as carbon tetrachloride (CCl4). Mice lacking Per1 slowed down the metabolic rate of toxins including CCl4, capsaicin, and acetaminophen, exhibiting relatively more residues in the plasma. Liver injury and fibrosis induced by acute and chronic CCl4 exposure were markedly alleviated in Per1-deficient mice. These processes involved the binding of PER1 protein and hepatocyte nuclear factor-1alpha (HNF-1α), which enhances the recruitment of HNF-1α to cytochrome P450 2E1 (Cyp2e1) promoter and increases Cyp2e1 expression, thereby promoting metabolism for toxins in the livers. These results indicate that PER1 mediates the metabolism of toxins and appropriate suppression of Per1 response is a potential therapeutic target for toxin-induced hepatotoxicity.

This study was carried out to investigate the influence of dietary lipid levels on the growth, immune response, and disease resistance of hybrid yellow catfish (Pelteobagrus fulvidraco♀×P. vachelli♂) during overwintering. Yellow catfish (initial body weight: 49.42 ± 1.33 g) were fed isonitrogenous diets (crude protein 40%) with three lipid levels (low lipid: 8.57%, medium lipid: 12.65%, and high lipid: 16.60%) for five weeks before the overwintering stage, and then all fish were fasted during overwintering. After overwintering, a bacterial challenge test was performed. The results showed that dietary lipid levels had no influence on the growth of hybrid yellow catfish before or after overwintering, but the high lipid (16.60%) diet significantly reduced the survival rate of the fish after bacterial challenge (P

Zinc (Zn) is an essential micromineral for fishes and is closely related to many biochemical processes. This study was designed to determine the effects of dietary Zn supplied in practical diets on the pond-raised hybrid snakehead (Channa maculate ♀ × C. argus ♂). Five extruded diets were supplemented with different Zn sulfate levels (analysed Zn values: 42.33, 65.79, 82.27, 100.41, and 120.18 mg kg-1). A total of 900 fish (initial weight 3.33 g) were divided into three net cages per treatment and fed twice daily to apparent satiety. The results indicated that dietary Zn influenced growth parameters, antioxidant capacity and innate immunity. The moisture and crude lipid contents of the whole body were significantly affected by dietary Zn concentration (P 0.05). However, copper (Cu) content in the whole body, vertebrae, and liver increased and then decreased as dietary Zn increased (P

This study investigates the effects of resale allowance on entry strategies, seller’s expected revenue, and social welfare in a second-price auction with two-dimensional private information on values and participation costs. We characterize the perfect Bayesian equilibrium in cutoff strategies and identify sufficient conditions under which the equilibrium is unique. Our analysis suggests that resale allowance leads the low-value bidder to become more aggressive on entry, while high-value bidder has a lower incentive to enter. Furthermore, the allowance of resale can increase the social welfare under a sufficient condition, and its effect on expected revenue is ambiguous.

This study was conducted to investigate the effects of substitution of dietary fishmeal (FM) by compound plant protein supplemented with essential amino acids on growth performance, plasma physiology, and muscle growth-related genes of gibel carp (Carassius auratus gibelio). Four diets with equal digestible protein were prepared, where 30FM (control feed) contained 30% FM and land animal protein as a protein source, 10FM contained 10% FM, PMAa contained full plant meal (PM) supplemented with crystalline amino acid, and PM contained full PM feed. There was no significant difference in the specific growth rate (SGR) with 30FM, 10FM, and PMAa diets (p > 0.05); however, the SGR of PM group was the lowest with significant difference (p < 0.05). Feed efficiency of the PM group was the lowest with significant difference (p < 0.05). The whole-body crude protein content of fish in PMAa group was significantly higher than that in each group with additional FM (p < 0.05). There were no significant differences in plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C), and free amino acid profile of 30FM, 10FM, and PMAa groups (p > 0.05); however, they were significantly higher than that in PM group (p < 0.05). The expression of key genes in the TOR signaling pathway (tor, s6k1, 4e-bp2, and eif4e), autophagy (ulk1 and atg13), and ubiquitin–proteasome (trim63 and znrf2) system of the PMAa group was similar to that of the FM group (p > 0.05), indicating that the muscle growth-related biomarker genes were positively regulated by the appropriate dietary amino acid composition at the transcriptional level. These results suggest that FM in gibel carp diet can be totally replaced by PM without negative impact on growth performance and muscle growth-related biomarkers at the transcriptional level, which provided the requirement of digestible protein and balanced amino acid profile is satisfied.

An 8-week feeding trial was conducted to explore the effects of replacement of dietary fishmeal by cottonseed protein concentrate (CPC) on growth performance, liver health, and intestine histology of largemouth bass. Four isoproteic and isolipidic diets were formulated to include 0, 111, 222, and 333 g/kg of CPC, corresponding to replace 0% (D1), 25% (D2), 50% (D3), and 75% (D4) of fishmeal. Two hundred and forty largemouth bass (15.11 ± 0.02 g) were randomly divided into four groups with three replicates per group. During the experiment, fish were fed to apparent satiation twice daily. Results indicated that CPC could replace up to 50% fishmeal in a diet for largemouth bass without significant adverse effects on growth performance. However, weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), and condition factor (K) of the largemouth bass were significantly decreased when 75% of dietary fishmeal that was replaced by CPC. The whole body lipid content was increased with the increasing of dietary CPC levels. Oil red O staining results indicated that fish fed the D4 diet showed an aggravated fat deposition in the liver. Hepatocytes exhibited serious degeneration, volume shrinkage, and inflammatory cells infiltration in the D4 group. Intestinal villi appeared shorter and sparse with severe epithelial damage in the D4 group. The transcription levels of anti-inflammatory cytokines, such as transforming growth factor β (tgf-β), interleukin 10 (il-10), and interleukin 11 β (il-11β), were downregulated in the D4 group. The lipid metabolism-related genes carnitine palmitoyl transferase 1 (cpt1), peroxisome proliferator-activated receptor α (pparα), and target of rapamycin (TOR) pathway were also significantly downregulated in the D4 group. It was concluded that suitable replacement of fishmeal by less than 222 g CPC/kg diet had a positive effect on growth performance of fish, but an excessive substitution of 75% fishmeal by CPC would lead to the suppressed growth, liver inflammation, and intestinal damage of largemouth bass.

Clostridium autoethanogenum protein (CAP) is a novel protein source for aqua-feeds. The present study aimed to investigate the effects of dietary CAP on growth performance, immunity, and liver health status of juvenile largemouth bass (Micropterus salmoides). Four isonitrogenous and isolipid experimental diets were formulated to replace 0% (D1, control), 25% (D2), 50% (D3), and 75% (D4) of fish meal by CAP. Fish (15.05 ± 0.08 g) were randomly fed one of four experimental diets for 8 weeks. The results showed that weight gain (WG), specific growth rate (SGR), feeding rate (FR), viscerosomatic index (VSI), and hepatosomatic index (HSI) of the D4 group were significantly lower than D1, D2, and D3 groups (P < 0.05). With the increase of substitution level, the total antioxidant capacity (T-AOC) of liver tissue was significantly decreased, while the plasma alkaline phosphatase (AKP) activity was significantly increased (P < 0.05). Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly higher in D3 and D4 groups than in D1 and D2 groups (P < 0.05). Replacing 50 or 75% fish meal by CAP significantly induced the transcription level of apoptosis-promoting genes (bcl-2-associated death protein [bad] and bcl-2-assoxicated × protein; bag [bax]), anti-apoptosis-related genes (tumor protein 53 [p53] and b-cell lymphoma-2 [bcl-2]), and the apoptotic Caenorhabditis elegans (C. elegans) death gene-3 like caspases (cysteine-aspartic proteases-3 [caspase-3], cysteine-aspartic proteases-8 [caspase-8], cysteine-aspartic proteases-9 [caspase-9], and cysteine-aspartic proteases-10 [caspase-10]) in liver, while suppressed the gene expression of the inflammatory factors [interleukin-1β (il-1β), interleukin-8 (il-8), and tumor necrosis factor, tnf ] in head kidney. At the same time, dietary inclusion of CAP elevated the protein expression of bcl-2, autophagy microtubule-associated protein light chain 3A/B (LC3A/B-I), and LC3A/B-II by inhibiting the phosphorylation of the mammalian target of rapamycin (mTOR; P < 0.05). Moreover, the apoptosis rate of the D3 and D4 groups was significantly increased (P < 0.05). Taken together, these results indicated that the optimal level of CAP-replacing fish meal should be

An 8-week feeding trial was carried out with various lipid level (2.30 %, 6.31 %, 8.98 %, 12.93 %, 16.08 %, and 18.99 %) diets to investigate the effects on growth performance, body composition, and feed utilization of juvenile spotted knifejaw Oplegnathus punctatus. After the feeding experiment, the weight gain (WG) and specific growth rate (SGR) significantly elevated with raising the dietary lipid level to 12.93 %, and then decreased when dietary lipid further increased (p < 0.05). The tendencies of feed efficiency (FE), protein efficiency ratio (PER), nitrogen retention (NR), and energy retention (ER) were consistent with the growth performance (p < 0.05). The lipid retention (LR) significantly decreased with dietary lipid increasing (p < 0.05). The fish consuming 2.30 % and 6.31 % lipid diets had significantly elevated hepatosomatic index (HSI) (p < 0.05). The intraperitoneal fat ratio (IPF) increased with the increase of dietary lipid levels (p < 0.05). The elevation of dietary lipid levels significantly increased the lipid concentrations in the whole body, dorsal muscle, and liver (p < 0.05). The highest liver glycogen deposition was found in the 2.30 % dietary lipid treatment (p < 0.05). The fish fed the diets added with 12.93 % lipid diet had the highest serum protein concentration (p < 0.05). The lowest total cholesterol (TC) content in the serum was detected in 2.30 % dietary lipid treatment (p < 0.05). The fish fed diets with 2.30 % or 18.99 % lipid obtained elevated serum AST and ALT activities (p < 0.05). The regression analysis in second order polynomial and two slope broken-line mode based on SGR and FE indicated that diet containing 10.46–12.83 % lipids was optimal for juvenile O. punctatus to obtain best growth performance and feed efficiency.

A 48 days growth trial investigated the effects of dietary protein on growth, feed utilization in non-transgenic and GH (growth hormone gene) transgenic common carp (Cyprinus carpio L.). Transgenic common carp (TG fish) and non-transgenic (NT fish) were fed with seven diets of different protein levels (20%, 24%, 28%, 32%, 36%, 40%, 44%). The results showed that, TG fish obtained higher growth and feed utilization. NT fish showed higher whole-body protein and lipid. Compared to NT fish, the lower whole-body lipid of TG fish was mainly achieved by reducing fat synthesis and promoting fatty acid β-oxidation, including down-regulation of mRNA levels of acetyl-CoA carboxylase 1 (acc1), acyl-CoA desaturase 1 (scd1) and fatty-acid synthase (fas), upregulation of mRNA level of carnitine palmitoyl transferase 1a (cpt-1a). Plasma glucose levels were found higher in TG fish than NT fish, which might be caused by the inhibition of glycolysis (pfk, p

To determine the impact of replacing fish meal (FM) in the diet with various levels of soybean meal (SBM) on the spotted knifejaw Oplegnathus punctatus, a 56 day feeding trial was done. Seven diets were formulated with SBM to replace 0% (SBM0), 30% (SBM30), 40% (SBM40), 50% (SBM50), 60% (SBM60), and 70% (SBM70) of FM protein, and SBM50 + T was developed on the basis of SBM50 with the addition of 1.2% taurine. There were triplicate groups of 18 fish (initial weight: 14.62 ± 0.02 g). The weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) values of the SBM0, SBM30, and SBM50 + T groups were found to be significantly higher than those of the SBM60 and SBM70 groups (p < 0.05). The daily energy gain (DEG), daily nitrogen gain (DNG), daily lipid gain (DLG), energy retention (ER), nitrogen retention (NR), and lipid retention (LR) values decreased significantly with increasing dietary SBM levels (p < 0.05). The highest retention of most amino acids (except lysine) was observed in the SBM30 group (p < 0.05). The lipid content of the whole body and dorsal muscle decreased significantly as dietary SBM levels increased (p < 0.05). Fish fed the SBM70 diet had the lowest serum triglyceride (TG) concentrations (p < 0.05). The effects of different treatments on total cholesterol (T-CHO) were not significant (p > 0.05). Fish fed the SBM0 and SBM30 diets had the highest amylase (AMS) and lipase (LPS) activities (p < 0.05). The lowest liver superoxide dismutase (SOD) and catalase (CAT) activities were observed in the SBM70 group. The malondialdehyde (MDA) concentration of the SBM50 to SBM70 groups were significantly higher than that of other groups (p < 0.05). The levels of interleukin 8 (il-8) mRNA were highest in fish fed the SBM0, SBM30, and SBM50 + T diets (p < 0.05), while the level of transforming growth factor β1 (tgf-β1) was the opposite (p < 0.05). According to the broken line regression of WG and FE, the highest level of FM substitution by SBM for Oplegnathus punctatus was 24.07–25.31%.

A 56-day fish feeding trial was conducted to investigate the effects of dietary Arthrospira platensis on the growth performance, body chemical composition, serum biochemical parameters and antioxidant capacity in hybrid yellow catfish (Pelteobagrus fulvidraco♀ ×Pelteobagrus vachelli♂). Three experimental feeds were prepared. The protein concentrations of these three experimental diets were similar; one was a commercial diet (CD). The other two diets were with (AP+) or without (AP−) 1% A. platensis. A total of 270 hybrid yellow catfish were randomly divided into nine cages (three cages per treatment, 30 fish per tank) and fed experimental diets. In order to avoid the influence of different protein sources, the proportion of protein in each feed formulation was kept the same. The results revealed that dietary supplementation of 1% A. platensis significantly increased the food intake and growth performance of hybrid yellow catfish (P

Abstract Background Person-centered care is widely recognized as a gold standard and is based on a supportive psychosocial climate for both residents and staff in nursing homes. Residents and staff may have different perspectives as to whether the climate in which they interact is person-centered, perhaps due to their different expectations of the nursing home environment and the provision of care services. The aim of this study was to explore and compare resident and staff perspectives of person-centered climate in aged care nursing homes. Methods This is a descriptive cross-sectional study using a cluster random sampling method. The study collected data in 2016 from residents (n = 251) and nursing staff (n = 249) in 23 nursing homes using a Person-centered Climate Questionnaire-Patient version and Person-centered Climate-Staff version. T-tests for independent-samples were used to compare scores ranked by nursing staff and residents. Results The mean scores of ‘A climate of safety’ subscale and ‘A climate of everydayness’ subscale rated by residents were significantly lower than those rated by nursing staff. The mean scores of ‘A climate of hospitality’ rated by residents were very low among the three subscales, an indicator of the need to improve a more home-like environment for residents. Residents in larger size nursing homes showed a higher score of person-centered climate compared with their counterparts in small size nursing homes. Conclusions This study reveals that the perspectives and perceptions of person-centered climate differ between residents and nursing staff. Therefore, both resident and staff perspectives should be taken into account in attempting to improve person-centered climate for better care outcomes.

Atractylodes macrocephala polysaccharide (AMP) can enhance antioxidant defense and anti-inflammation, as the tolerance levels of AMP in aquaculture is important for additive utilization. However, the tolerance dose of AMP is unknown. We assess the tolerance levels of AMP in juvenile largemouth bass (3.38 ± 0.11 g) by feeding them a 0, 400, 4000, or 8000 mg/kg AMP supplemented diet for 10 weeks. The 400 mg/kg AMP dose increased growth performance. The Nrf2/Keap1 signaling pathway was activated, as indicated by Keap1 and Nrf2 protein levels in the liver. Enhanced activity of antioxidant enzymes (SOD, GPx), together with increased mRNA levels of antioxidant genes (sod, gpx) and decreased accumulation of reactive oxygen species (ROS) and MDA, was found in the liver, implying the antioxidant effect of AMP. Nutrient absorption was enhanced by AMP, as reflected by the increased length of intestinal villi and microvilli. However, 4000 and 8000 mg/kg AMP induced oxidant stress, as indicated by increased plasma ALT and AST content and decreased mRNA levels of antioxidant genes (sod, gpx) in the liver and intestinal tissues. Inflammatory reactions were also induced by high doses of AMP, as reflected by enhanced levels of pro-inflammatory cytokines (tnfα, nfκb) in the liver, intestinal, and kidney tissues and inhibited levels of anti-inflammatory cytokines (tgfβ, iκb). Histological analysis reveals inflammatory cell infiltration and tissue damage. Thus, the safe tolerance margin of AMP supplement for largemouth bass was 400–4000 mg/kg.

Our previous studies in gibel carp (Carassius gibelio) have shown that cadmium (Cd) exposure elicits deleterious effects depending on the genetic background, and thus we hypothesized that mitigation via nutritional intervention may vary between strains. Therefore, two gibel carp strains (the A and F strains) were fed diets supplemented with 0% or 1% taurine for 8 weeks prior to 96 h Cd exposure, and the responses of antioxidant pathways, endoplasmic reticulum (ER) stress, autophagy, and apoptosis were investigated. The results showed that taurine supplementation had no effect on the growth performance of gibel carp. After Cd exposure, histological damage to mitochondria and ER, induction of oxidative stress and antioxidant responses, occurrence of ER stress, and apoptotic signals were observed in the livers. Upon the diet effects, taurine supplementation alleviated the ER-stress-induced autophagy and apoptosis after Cd exposure and stimulated antioxidant pathways. Regarding the difference between strains, taurine played a protective role in alleviating Cd toxicity through the antioxidant response, ER stress, and autophagy in the F strain, whereas such effects were achieved by the attenuation of apoptosis in the A strain. Taken together, our results demonstrate the potential use of taurine in the mitigation of heavy metal toxicity in aquatic organisms.

Previous studies have found that vitamin C (VC) has protective effects in fish. However, the efficacy of VC on hypoxia-induced liver injury in fish remains unknown. Therefore, to investigate the protective mechanism of VC on liver injury after acute hypoxic stimulation in fish, gibel carp were fed a diet containing VC for eight weeks, then were subjected to acute hypoxia stimulation. The specific growth rate of fish was increased by the supplementation of VC. Plasma stress markers (glucose, lactic acid, and cortisol) were decreased by the VC supplementation. Moreover, the levels of the inflammatory cytokines (tnf-α, il-2, il-6, and il-12) were increased by enhancing the Nrf2/Keap1 signaling pathway. Upregulation of the antioxidant enzymes activity (CAT, SOD, and GPx); T-AOC; and anti-inflammatory factors (il-4 and tgf-β) highlighted the antioxidant and anti-inflammatory activities of VC. The results showed that VC reduced the apoptotic index of the fish hypothalamus. The expression of GRP78 protein in the liver and endoplasmic reticulum stress and apoptosis induced by hypoxia were inhibited by VC. Taken together, the results indicate that VC can attenuate oxidative damage, inflammation, and acute hypoxia induced apoptosis in gibel carp via the Nrf2/Keap1 signaling pathway. The results identify a new defense strategy of gibel carp in response to hypoxic conditions.

In aquaculture, fish are often exposed to several stress conditions, which will cause oxidative disorder and bring about health and quality problems. Arthrospira platensis contains abundant bioactive ingredients, which are beneficial for animal health. This study was conducted to investigate the effects of A. platensis on pigmentation, antioxidant capacity, and stress response after air exposure of fish. A total of 120 yellow catfish Pelteobagrus fulvidraco (initial weight 70.19 ± 0.13 g) were divided into three tanks per treatment and fed diets supplemented with 0 g kg−1 A. platensis (CON) and 20 g kg −1 A. platensis (AP) for 65 days. The results indicated that dietary A. platensis had no effects on the growth of yellow catfish. The AP diet significantly reduced lactic acid (LD) and cortisol levels stimulated by air exposure stress (p < 0.05). Dietary A. platensis significantly increased plasma superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities and glutathione (GSH) contents, and the relative expression levels of sod and cat, to protect against oxidative stress caused by air exposure (p < 0.05). The AP diet significantly improved the relative expression level of nrf2 (nuclear factor erythroid-2 related factor 2), while the relative expression level of keap1 (kelch-like ECH associated protein 1) was downregulated, and the protein levels of liver Nrf2 were significantly increased after air exposure stimuli (p < 0.05). Dietary A. platensis significantly increased skin lutein contents, increased skin redness, yellowness and chroma (p < 0.05), and improved body color abnormalities after oxidative stress caused by air exposure stimuli. Skin yellowness was associated with lutein contents and the expression levels of some antioxidant genes to varying degrees. Overall, dietary A. platensis could be utilized as a feed additive to activate the antioxidant response, as well as alleviate oxidative stress and pigmentation disorder induced by air exposure.