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The study was conducted to investigate the effects of taurine (Tau) alone or in combination with fish protein hydrolysate (FPH) on growth performance, the expression of Tau transporter (TauT) and metabolic profile in juvenile turbot. FM, FPH0, FPH0+T, FPH10 and FPH10+T diets, respectively, contained 300, 150, 150, 80, and 80 g/kg fishmeal. FPH10 and FPH10+T diets contained 62 g/kg FPH. FPH0+T and FPH10+T diets were, respectively, prepared by supplementing the FPH0 and FPH10 diet formulations with 8 g/kg Tau. Specific growth rate was the highest in FM group and the lowest in FPH10 group. TauT mRNA levels in fish fed Tau supplemented diets were significantly lower than that in Tau unsupplemented diets. NMR‐based metabolomics analysis showed that Tau contents in liver of FPH0+T and FPH10+T were significantly higher than that of FM, FPH0 and FPH10. In muscle, Tau contents were significantly decreased in the FPH10+T versus FPH0 and the FPH10+T versus FPH10 comparisons. In conclusion, 62 g/kg FPH to replace fishmeal may not affect Tau synthesis, transport and metabolism. However, Tau supplemented alone or in combination with a certain level of FPH could reduce the requirement for Tau synthesis and transport and increased Tau levels in muscle and liver. [ABSTRACT FROM AUTHOR]

A 10‐week feeding experiment in indoor flow‐through seawater system was conducted to investigate the effects of dietary krill hydrolysate on the expression of growth‐related genes in juvenile turbot (Scophthalmus maximus L.; initial body weight 9.45 ± 0.01 g). Three isonitrogenous and isolipidic experimental diets containing high plant protein were formulated to contain 0 (control), 50 g/kg (LKH) and 100 g/kg (HKH) krill protein hydrolysate (KH) to replace fishmeal, respectively. Triplicate groups of 30 fish were fed for 10 weeks to apparent satiation twice daily. At the end of the feeding trial, the mRNA expressions of insulin‐like growth factor (IGF‐1) gene in liver, peptide transporters (PepT1) gene in pyloric caeca and proximal intestine and neuropeptide Y (NPY) gene in brain in all groups were determined. IGF‐1, PepT1 and NPY expression levels in HKH group were significantly increased compared with those of LKH and control (p < 0.05), which was consistent with the SGR, feed efficiency, PER and PPV. These results indicated that dietary 100 g/kg krill hydrolysate could improve growth performance and upregulate the mRNA expression of IGF‐1, PepT1 and NPY genes in juvenile turbot. [ABSTRACT FROM AUTHOR]

Abstract: The lipid‐regulating effects of astaxanthin (ASTX) have been widely reported in terrestrial animals. However, little relevant information has been available in fish although ASTX has been used as exogenous pigment and antioxidant in fish feed. A 74‐day feeding study was conducted to investigate the effects of dietary ASTX on lipid accumulation in the marine teleost tiger puffer. Four experimental diets differing only in ASTX supplementation, that is, 0 (control), 50 (ASTX50), 100 (ASTX100) and 500 (ASTX500) mg kg‐1, were randomly assigned to 12 tanks of juvenile tiger puffer. Compared to control, the liver lipid content in group ASTX50 was significantly higher, while those in groups ASTX100 and ASTX500 were lower. The muscle lipid contents in group ASTX500 were significantly higher compared to control. Group ASTX50 had the best growth performances, while diet ASTX500 seemed to have adverse effects. In the liver, compared to control, groups ASTX50 and ASTX100 showed significantly lower mRNA expressions of genes related to triglycerol synthesis and fatty acid synthesis, transport and uptake, but higher expressions of genes related to β‐oxidation and monoglycerol hydrolysis. In the muscle, compared to control, ASTX100 showed higher expressions of genes related to β‐oxidation. ASTX50 resulted in higher contents of saturated and monounsaturated fatty acids but lower contents of n‐3 polyunsaturated fatty acids in fish. In conclusion, astaxanthin in diets for tiger puffer differentially regulated the lipid accumulation in the liver and muscle, both in dose‐dependent manners. Excess dietary astaxanthin (500 mg/kg) had adverse effects on tiger puffer. [ABSTRACT FROM AUTHOR]

In this study, putative cDNA of three fatty acid transport protein ( FATP) isoforms, that is FATP1, FATP4 and FATP6, was cloned and characterized from the liver of Japanese seabass ( Lateolabrax japonicus), and their expression in response to diets with different arachidonic acid ( ARA) levels (0.05%, 0.22%, 0.37%, 0.60%, 1.38% and 2.32% of dry matter) was investigated through a feeding trial. Two subtypes of FATP1, that is FATP1a and FATP1b, were cloned for the first time. The Japanese seabass FATPs showed high identity to their orthologs in other fish species and mammals, but Japanese seabass FATP6 showed low identity to Japanese seabass FATP1 and FATP4. FATP1a gene was highly expressed in brain, liver and eye, whereas FATP1b had the highest gene expression in gill, followed by kidney, skin, eye, muscle and heart. FATP4 gene was primarily expressed in intestine, brain and eye. However, FATP6 had very low gene expression levels in almost all tissues. High levels of dietary ARA (0.60%~2.32%) enhanced the gene expressions of FATP1a and FATP4 in the intestine and the gene expression of FATP1a in the muscle, whereas the dietary ARA supplementation reduced the FATP1b mRNA expression in the liver. The gene expression of FATP1a, FATP4 and FATP6 in the liver, as well as the FATP4 gene expression in the muscle, was not significantly affected by dietary ARA levels. To our knowledge, this is the first study investigating the regulation of FATP gene expressions by dietary ARA. [ABSTRACT FROM AUTHOR]

A 1H NMR-based metabolomics approach was to explore the effect of ultrafiltered fish protein hydrolysate ( UF) levels on the liver and muscle metabolic profile of juvenile turbot ( Scophthalmus maximus L.). Fish protein hydrolysate ( FPH) was produced from by-products by enzymatic treatment, and UF was obtained by diluting FPH followed filtration. Fish were fed diets containing fish meal protein, which was, respectively, replaced by UF protein 0, 50, 100, 150 and 200 g kg−1 of dietary total protein ( UF-0, UF-5, UF-10, UF-15 and UF-20) for 68 days. OPLS- DA of liver and muscle showed that high levels of UF in diets may lead to corresponding tissue metabolites changes. In liver tissue, changing metabolites included dimethylamine, N,N-dimethylglycine, valine, isoleucine, leucine, arginine and alanine and were mainly involved in choline metabolism and amino acid metabolism. For muscle tissue, changing metabolites included lactate, alanine, proline, fumarate, tyrosine, histidine, cystathionine and taurine. And the metabolites were mainly involved in glycolysis and gluconeogenesis, proline metabolism and taurine metabolism. 1H NMR-based metabolomics is a useful approach to investigate different levels of UF on metabolic profile in liver and muscle tissues combined with the growth. [ABSTRACT FROM AUTHOR]

A 10-week feeding experiment was conducted to investigate the effects of different types of dietary protein hydrolysate ( PH) on growth performance, body composition, trypsin activity and serum transaminase of juvenile turbot. Four high plant protein diets contained different types of PH, fish PH ( FPH), yeast PH ( YPH), pig blood PH ( PBPH) and soy PH ( SPH), replacing 10% fishmeal of the basal diet. The basal diet with 30% fishmeal and no PH was used as the control diet (C). Each diet was assigned to triplicate groups of 30 fish. The specific growth rate ( SGR) was not significantly different between groups C and FPH, but groups C and FPH showed significantly higher SGR than other groups. The feed efficiency ratio ( FER) and protein efficiency ratio ( PER) were not significantly different among groups C, FPH and YPH, but groups PBPH and SPH showed significantly lower FER and PER than groups C and FPH. Group PBPH showed significantly higher hepatosomatic index than other groups except YPH. Fish fed YPH showed significantly lower whole-body protein content, but significantly higher whole-body lipid content than fish fed diets C, FPH and PBPH. The activities of serum GOT and GPT in group PBPH were higher than those in groups C, FPH and YPH. These results suggested that when used at a low level in high plant protein diets for juvenile turbot, FPH is a good alternative protein source and YPH also has the application potential, but PBPH and SPH can cause negative impacts on fish growth and health. [ABSTRACT FROM AUTHOR]

In fish, it has been debatable whether branched-chain amino acid (BCAA) imbalance will show antagonistic effects on the growth and the concentrations of plasma or tissue BCAAs. The objective of this study were to investigate the effects of incremental levels of dietary leucine on the growth (trial 1) and potential antagonistic effects between BCAAs (trial 2) in tiger puffer. This study was composed of two separate trials. In trial 1, six experimental diets were prepared by the basal diet containing incremental levels of leucine (19.3, 24.9, 28.6, 32.6, 36.3 and 40.7 g kg−1 of dry diet). In trial 2, five experimental diets were formulated to contain a proper amount of leucine (29.0 g kg−1 of dry diet), a deficiency of leucine (12.6 g kg−1 of dry diet), an excess of leucine (55.9 g kg−1 of dry diet), an excess of isoleucine (43.2 g kg−1 of dry diet) and an excess of valine (49.6 g kg−1 of dry diet). All diets in two trials were fed to fish in triplicate net cages and polyethylene tanks, respectively. In trial 1, growth increase relative to initial body weight was 206.2–227.5%, while growth performance and body condition indices were not significantly affected by different levels of dietary leucine and did not show significantly linear or quadratic relationships with incremental levels of dietary leucine. In trial 2, growth performance also did not exhibit significant differences in fish fed imbalanced BCAAs diets. Compared with a proper amount of leucine group, the activities of branched-chain α -keto acid dehydrogenase enzyme complex (BCKDH) and BCKDH kinase increased in the leucine or valine excessive diet. The expressions of amino acid transporters (B0AT1 and y+LAT2) and peptide transporter 1 (PepT1) were down-regulated by excessive dietary leucine, isoleucine or valine. Free valine concentration in plasma and muscle increased in the leucine deficient diet compared to a proper amount and an excess of leucine in diets. In conclusion, the growth of tiger puffer was not affected by the diets containing 12.6–55.9 g kg−1 leucine. An excess of dietary leucine, isoleucine or valine possibly resulted in antagonism between BCAAs based on the activities of enzymes related to BCAA catabolism and the expressions of amino acid transporters, although the growth was not significantly depressed by one excessive BCAA when the other two BCAAs met the requirements for tiger puffer. In addition, plasma and muscle valine levels indicated that the antagonism of valine to leucine were observed in the leucine deficient diet, but not in the leucine excessive diet. • The growth of tiger puffer was not affected by the diets containing 12.6–55.9 g kg−1 leucine. • An excess of dietary BCAA possibly resulted in antagonism between BCAAs in tiger puffer. • The antagonism of valine to leucine were observed in the leucine deficient diet. [ABSTRACT FROM AUTHOR]

An eight week feeding trial was conducted to investigate the effect of taurine supplementation on growth performance, sulfur amino acid concentrations, the activity and gene expression of enzymes related to taurine synthesis, and gene expression of taurine transporter (TAUT) in tiger puffer (Takifugu rubripes). Test diets were respectively supplemented with 0, 3, 6, 9, 12 and 20 g kg−1 taurine (the T0, T3, T6, T9, T12 and T20 diets) and a control diet was supplemented with 12 g kg−1 cysteine (the Cys diet). All experimental diets were fed to triplicate groups of 25 fish (initial weight 20.05 ± 0.06 g). Dose responses were observed in terms of specific growth rate and feed efficiency ratio. Dietary taurine requirement was estimated at 5.25 and 8.23 g kg−1 of dry matter of the diet based on regression analysis for specific growth rate and feed efficiency ratio, respectively. Free taurine concentrations of muscle and liver tissues increased with the increase of dietary taurine concentration. However, there was no significant difference in free taurine concentrations in muscle or liver between the Cys and T0 groups (p >.05). Free methionine concentration of liver tissue gradually increased with the increase of dietary taurine, which implied that exogenous taurine appeared to spare hepatic methionine. Cysteine sulfinic acid decarboxylase (CSD) activity and mRNA level in liver were down-regulated in the T9, T12 and T20 groups compared with the T0 group (p <.05), while no statistical difference was observed in cysteine dioxygenase (CDO) activity and expression between the T0 group and the taurine supplementation groups (the T3, T6, T9, T12 and T20 groups (p >.05). TAUT mRNA levels in muscle had a decrease trend in fish fed diets containing 1.7 to 8.2 g kg−1 taurine (the T0, T3 and T6 groups), while there was no significant difference when dietary taurine concentrations increased from 8.2 to 21.9 g kg−1 (the T6, T9, T12 and T20 groups). In conclusion, tiger puffer cannot synthesize taurine in the liver at the level of cysteine used in this study, whereas a sparing effect on the methionine demand may be observed in liver by dietary taurine supplementation. Our data indicates that taurine is a conditionally essential amino acid for tiger puffer, and the taurine requirement was estimated ranged from 5.25 to 8.23 g kg−1 of dry matter of the diet. • Taurine can't be synthesized in liver when tiger puffer was fed diets supplemented with cysteine. • A sparing effect on the methionine was observed in liver of tiger puffer by supplementing taurine to the feed. • Taurine is a conditionally essential amino acid for tiger puffer. • Dietary taurine requirement of tiger puffer estimated ranged from 5.25 to 8.23 g kg-1 of the diet. [ABSTRACT FROM AUTHOR]

Simple Summary: With the rapid development of aquaculture, searching for alternative lipid sources to fish oil has become an important task for the aqua-feed industry. Lard is regarded as a valuable alternative lipid source. Basa fish (Pangasius bocourti) offal oil also has a large annual production and high potential to be used in fish feeds. Evaluation of the efficacy of lard and Basa fish offal oil in fish feeds will provide useful information for their application in aquaculture. Both lard and Basa fish offal oil have high levels of saturated fatty acids and monounsaturated fatty acids. The "n-3 LC-PUFA sparing effects" of saturated fatty acids and monounsaturated fatty acids in fish feeds have been observed in many fish species. The present study was also aimed at validating the "n-3 LC-PUFA sparing effects" of saturated fatty acids and monounsaturated fatty acids in lard and Basa fish offal oil. Moreover, the effects of dietary lard and Basa fish offal oil on fish body composition and muscle quality were also evaluated. Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360–398%), feed intake (2.37–3.04%), feed conversion ratio (0.84–1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds. [ABSTRACT FROM AUTHOR]

Micro-perforated panel (MPP) absorbers exhibit multiple resonance bands with increased bandwidth narrowing and shifting in higher frequencies, limiting their effectiveness. This study investigates the effects of narrowing and shifting in higher-order resonance bands of MPP absorbers. First, an acoustic impedance model for MPP absorbers is introduced, and the narrowing and shifting coefficients are defined and modeled to quantify these effects. It is observed that a larger ratio of acoustic resistance to acoustic mass is favorable for reducing the narrowing and shifting effects. Subsequently, the theoretical model is validated using a numerical model, and a parametric study is conducted to explore the influence of geometric parameters on the narrowing and shifting effects. The study reveals that decreasing aperture and panel thickness, while increasing perforation ratio and cavity depth, reduces the narrowing and shifting coefficients. Remarkably, ultra-micro-perforated panels (UMPPs) with an aperture below 0.1 mm and perforation constant below 0.0046, having relatively larger acoustic resistance and smaller acoustic mass, demonstrate near-zero band narrowing and shifting. Finally, UMPPs are fabricated using micro-electro-mechanical systems (MEMS) technology, and their normal absorption coefficients are measured. Results align with theoretical predictions, confirming UMPPs' ability to achieve zero narrowing and shifting compared to ordinary MPPs and verifying the study's findings. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of combined replacement of fishmeal (FM) and fish oil (FO) with poultry byproduct meal (PBM) and mixed oil (MO, poultry oil: coconut oil = 1 : 1) on growth performance, body composition and muscle quality of tiger puffer (Takifugu rubripes). Fish with an average initial body weight of 14.29 g were selected for the feeding experiment. FM accounting for 0%, 5%, and 10% of the diet was replaced by PBM. For each grade of FM replacement, 5% FO or MO was used as added oil. The six experimental diets were designated as FO-FM, MO-FM, FO-5PBM, MO-5PBM, FO-10PBM, and MO-10PBM, respectively. Each treatment was performed in triplicate with 30 fish per replicate. The feeding period was 45 days. There was no significant difference in growth performance among the groups. Dietary supplementation of both PBM and MO had marginal effects on whole-fish proximate composition, except that dietary MO supplementation significantly increased the liver moisture content. In serum, there were no significant differences in contents of triglyceride, total cholesterol, total bile acid, and protein carbonyl among groups, but the malondialdehyde content was reduced by MO. The fatty acid composition in fish mirrored those in the diets, but the omega-3 sparing effects of saturated and monounsaturated fatty acid in MO can still be observed. Dietary PBM and MO had marginal effects on free amino acid composition and texture of fish muscle, but exerted complicated effects on the muscle volatile flavor compound composition. In conclusion, combined fishmeal (10% of the diet) and fish oil (5% of the diet) replacement with poultry byproduct and mixed oil (poultry oil + coconut oil) had no adverse effects on the growth performance and body proximate composition of farmed tiger puffer. However, these replacements changed the muscle flavor compound profile. [ABSTRACT FROM AUTHOR]

This study characterized four cholesterol transport-related genes, namely, lcat, acat1, acat2, and mttp, in juvenile tiger puffer in terms of tissue distribution (eye, heart, brain, skin, liver, spleen, muscle, and intestine) and nutritional regulation. Three feeding trials were conducted: (i) using diets with different cholesterol levels (0.11%, 0.65%, 1.10%, 2.32%, and 4.59% of dry matter); (ii) using diets with different lipid levels (8.05%, 12.02%, and 16.36% of dry matter); and (iii) a 1-month starvation experiment with different sampling times (Days 1, 4, 9, 16, and 31). The lcat, acat1, and acat2 were the most abundantly expressed in the liver, while mttp was the most abundantly expressed in the intestine. The lcat had a medium expression level in the muscle and skin but the lowest expression level in the spleen and intestine. The acat1 and acat2 had similar tissue distribution patterns, except that acat2 had a lower expression level in the heart but a higher level in the intestine than acat1. The mttp had medium expression levels in the liver and spleen but had the lowest level in the eye and skin. Different dietary cholesterol levels did not significantly affect the expression of these cholesterol transport genes in the liver and intestine, except that higher cholesterol levels (1.10%–4.59%) significantly downregulated the acat2 expression in the liver. Dietary lipid levels also had a mild influence on the hepatic expression of these genes, except that the diet with 12.02% lipid resulted in significantly higher acat1 expression than the one with 16.36% lipid. The starvation time significantly affected the hepatic expression of these genes. Long-term starvation (16 and 31 days) generally upregulated the hepatic gene expression of lcat, acat1, and mttp but generally downregulated that of acat2. This study provided preliminary knowledge about the tissue distribution and nutritional regulation of cholesterol transport-related genes in marine teleost. [ABSTRACT FROM AUTHOR]

Simple Summary: Enteromorpha prolifera is a type of green marine macroalgae that can cause green tides due to eutrophication. However, aquafeeds demand for E. prolifera meal has gradually exceeded annual E. prolifera production. Therefore, novel extraction methods should be applied to increase the bioactive compounds of E. prolifera at the level of large-scale industrialization to support the efficient utilization of E. prolifera in aquafeeds. According to biological activities of E. prolifera, the growth, feed intake, lipid metabolism, antioxidant, immune parameters and stress resistance were investigated in Pacific white shrimp. It confirmed that bio-products of E. prolifera based on different processing procedures could be used to reduce the amount of E. prolifera in feed without compromising its biological function. It will helpful to improve the application of E. prolifera in aquaculture. A feeding trial was conducted to evaluate the biological activities of Enteromorpha prolifera bio-products in the diets of Pacific white shrimp (Litopenaeus vannamei). Bio-products of E. prolifera included E. prolifera meal, E. prolifera hydrolysate and E. prolifera polysaccharide, which was supplied using different processing procedures. The control diet was supplemented without any E. prolifera bio-products or dietary attractants. Experimental diets were formulated to contain 0.2% and 0.4% of E. prolifera hydrolysate (EPH0.2% and EPH0.4%), 0.03% of E. prolifera polysaccharide (EPP0.03%), 3% of E. prolifera meal (EPM3%), 0.1% of dimethyl-β-propiothetn (DMPT0.1%) and 1% of squid paste (SP1%). Shrimp (~8 g) were randomly distributed in 21 tanks and fed for 44 days. Feed intake showed that 3% of E. prolifera meal and 0.4% of E. prolifera hydrolysate in diets exhibited similar attractant effects as 0.1% of DMPT. Gross qualitative observation showed that the abundance of lipid droplets decreased in hepatopancreas of the EPH0.4% and EPM3% groups, which were supported by hepatopancreas triacylglycerol (TG), where significantly lower concentrations were observed in the EPH0.4% and EPM3% groups compared with the control group. Similarly, TG and low-density lipoprotein cholesterol in serum significantly decreased in the EPH0.4%, EPP0.03% and EPM3% groups compared to the control group. Supplemental E. prolifera bio-products resulted in significantly higher serum glutathione level of EPP0.03% or superoxide dismutase activities of EPH0.4% and EPM3%, but significantly lower serum malondialdehyde level of EPM3%. In addition, tnf-α expression in hepatopancreas was significantly down-regulated in shrimp fed the EPH0.2%, EPH0.4% and EPM3% diets. Based on survival analysis, E. prolifera bio-products improved the resistance of shrimp to hypoxic stresses. Thus, this study confirmed that bio-products of E. prolifera supplied using different processing procedures could be used to reduce the amount of E. prolifera in feed of shrimp without compromising their biological functions. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of imbalanced dietary BCAAs, especially Leu, on the growth and BCAA metabolism in turbot. A control diet was formulated by keeping optimum levels of Leu, Ile and Val. Four experimental diets were prepared by removing supplemental crystalline Leu (deficiency) or supplementing double the amount of Leu, Ile or Val (excess) in the control diet. The growth was not significantly decreased by an excess of Leu, Ile or Val. Fish fed an excess of any particular BCAA significantly increased its postprandial (2 and 6 h) concentration in the plasma, muscles, and liver, but did not decrease the other two BCAA concentrations. The expression of intestinal b0at1 was down-regulated by excessive dietary Leu, Ile or Val. For BCAA catabolism, the mRNA levels of bcat2 in the muscles as well as bckdha and bckdhb in the livers of the Leu-deficient group were the lowest among all the groups, but were up-regulated by excess dietary Leu, Ile or Val. In conclusion, in terms of growth, turbot had high plasticity to an excess of any particular BCAA. Meanwhile, the antagonistic effect caused by an excess of one BCAA were reflected in intestinal amino acid absorption and BCAA catabolism. [ABSTRACT FROM AUTHOR]

Simple Summary: The supply of fish oil, which provides long-chain polyunsaturated fatty acids (LC-PUFA) but is mostly wild-caught, is stagnating, resulting in limited availability and high prices. Therefore, many alternative lipid sources, mainly vegetable oils and rendered animal fats, are increasingly being applied in fish feeds. However, these lipid sources do not contain LC-PUFA, and therefore lower the fillet quality in terms of the LC-PUFA content. Feeding strategies such as alternate feeding between fish oil- and alternative oils-based diets have been applied to maintain the n-3 LC-PUFA contents in farmed fish. The present study validated the relevant efficacy. A 12-week feeding experiment was conducted to evaluate the effects of replacing fish oil (FO) with beef tallow (BT) on the fatty acid composition of farmed tiger puffer (Takifugu rubripes). Two replacement strategies were used: a standard Graded Dietary Replacement of FO with BT (GDR strategy) and Alternate Feeding between FO- and BT-based Diets (AFD strategy). The positive and negative control diets were formulated with 6% FO (FO-C group) or BT (BT-C group) as the sole added lipid source. In the GDR strategy, three experimental diets were formulated, with 25, 50 and 75% of the added FO in the FO-C diet replaced with BT, named 25BT, 50BT and 75BT, respectively. In the AFD strategy, alternated feeding patterns between the FO-C and BT-C diet—namely, 1, 2 and 3 weeks with BT-C followed by 1 week feeding with FO-C (1BT-1FO, 2BT-1FO and 3BT-1FO, respectively)—were applied. Each diet or feeding strategy was assigned to triplicate tanks. The results showed that dietary BT inclusion reduced the contents of long-chain polyunsaturated fatty acids (LC-PUFA) in both the muscle and liver (edible tissues for this species) of the experimental fish, and the liver displayed a more drastic decrease than the muscle. The LC-PUFA content linearly decreased with the decreasing dietary FO levels in the GDR strategy. However, in the AFD strategy, a linear relationship was not observed between the LC-PUFA content and the FO feeding duration. The 3BT-1FO treatment resulted in higher LC-PUFA content than 2BT-1FO. When comparing the two strategies with the same final FO administration level—namely, 50BT vs. 1BT-1FO, and in particular, 75BT vs. 3BT-1FO—the AFD strategy resulted in higher LC-PUFA contents in both the muscle and liver than the GDR strategy. In conclusion, when FO was replaced with BT in the diets, alternate feeding between FO- and BT-based diets resulted in a higher LC-PUFA content than the standard direct replacement. Three weeks of feeding with BT-C followed by one week of feeding with FO-C appeared to be a good alternate feeding pattern. This study provided a promising strategy of FO-sparing in fish farming when the LC-PUFA contents were maintained as high as possible. [ABSTRACT FROM AUTHOR]

The fatty acid accumulation in fish tissues are closely related to fish sex, yet the sex differences in fish fatty acids have not been fully known. This experiment investigated the sex differences in fatty acid composition of Chinese tongue sole (Cynoglossus semilaevis), which have typical sexual dimorphism and reversal. Three sexes, namely females, males and pseudomales, were involved in this study. Five batches of fish samples were collected from different fish farms in Shandong Province, China. These fish were identified to be at the gonadal development stage of III–IV. The disparity of fatty acid between sexes (female vs male and pseudomale vs. male) was evaluated by the distance coefficient (Dsex) and multi-variate similarity of percentages analysis (SIMPER). The highest Dsex values between females and males were found in gonad, followed by liver and eye. The fatty acids that differed between females and males were mainly DHA, 16:1n-7, 18:1n-9, and 18:0. The sex difference in DHA and 18:1n-9 contributed significantly to the overall sex difference in fatty acid of brain, eye, and gonad, whereas that in 16:1n-7 contributed significantly in heart, gill, liver, and muscle. The sex difference in 18:0 contributed significantly to the overall sex difference in fatty acid of heart, gill, gut, and skin. The sex differences in fatty acid between pseudomales and males were generally insignificant. In conclusion, at this gonadal development stage (III–IV), the sex differences in fatty acid between female and male Chinese tongue sole have emerged, mainly in the gonad. The testes had higher DHA levels but lower levels of 16:1n-7 and 18:1n-9 than ovaries. In addition, for pseudomales, the phenotypic sex more substantially determined the fatty acid composition than the genetic sex. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the effects of dietary DHA/EPA ratio on lipid accumulation in farmed fish, with an 80-day feeding trial on tongue sole Cynoglossus semilaevis , a typical marine flatfish. Six experimental diets differing basically in DHA/EPA ratio, i.e., 0.61, 1.02, 1.46, 1.91, 2.32, and 2.75, were randomly assigned to 18 tanks of juvenile tongue sole. Fish were reared in a flow-through seawater system and fed to apparent satiation twice daily. Compared to very low (0.61) or high (2.32 and 2.75) dietary DHA/EPA levels, moderate dietary DHA/EPA ratios of 1.02 and 1.46 induced higher lipid accumulation in fish flesh and whole fish. Although also inducing increased liver lipid accumulation, the moderate dietary DHA/EPA ratios did not compromise the fish health in terms of growth performances and hematological parameters. The fatty acid profile of fish tissues reflected closely those of the diets, but DHA had more efficient deposition in fish flesh than EPA. Excess EPA or DHA in diets down-regulated the mRNA expression of lipogenic genes in fish tissues, and DHA seemed to be more efficient than EPA in up-regulating gene expression of β-oxidation-related proteins. Both esterification and hydrolyzation of triglycerides in fish tissues seemed to be more active in groups with intermediate DHA/EPA ratios (1.02 and 1.46). The present study provided a new way to modulate the nutritive quality of farmed fish, as well as to make better use of precious LC-PUFA resources. [ABSTRACT FROM AUTHOR]

Simple Summary: In some fish farming practices, cholesterol has been used as a feed additive for growth stimulation. Therefore, it is important to increase our knowledge and experience about dietary cholesterol effects on fish. This study provides useful information for the application of cholesterol in fish diets by analyzing the muscle lipidomics changes in turbot and tiger puffer in response to dietary cholesterol supplementation. Exogenous cholesterol has been supplemented into aqua-feeds due to the reduced proportions of fishmeal and fish oil. This study aimed to investigate the effects of dietary cholesterol supplementation on the muscle lipidomics of two marine fish species, turbot and tiger puffer. A 70-day feeding trial was conducted, where two low-fishmeal diets supplemented with 0 or 1% cholesterol were used. The lipidomic analysis with targeted tandem mass spectrometry showed that, in turbot, a total of 49 individual lipids exhibited significant differences in their abundance in response to dietary cholesterol, whereas the number was 30 for tiger puffer. Dietary cholesterol up-regulated the abundance of cholesterol and cholesterol ester in both species. In turbot, the dietary cholesterol also increased the abundance of triacylglycerol and acylcarnitine, whereas in tiger puffer, it primarily regulated the abundance of phospholipids and BMP. This was the first time the responses of marine fish muscle lipidomics to dietary cholesterol supplementation have been investigated. [ABSTRACT FROM AUTHOR]

As a widely used dynamic computation method for seismic response analysis of structures, time history analysis (THA) can be a time-consuming procedure in some situations. In order to reduce the calculation time, this study proposed a novel strong ground motion duration which can truncate the head and tail weak signals of records before THA. The initial point of proposed duration refers to the concept of bracketed duration, while the termination point is determined by the maximum displacement responses of equivalent single-degree-of-freedom (SDOF) systems of the structure. The relationship between the fundamental period and period-lengthening level of structure is counted from previous research and fitted with a formula which is used to compute the period range of equivalent SDOF systems. After comparing the structural responses and time-saved percentage of truncated records by proposed duration with those by other definition of durations, results prove that the proposed duration has significant time-saving procedure and reliable computation results on THA. • A novel strong ground motion duration is proposed to save computation time. • The duration is used to truncate ground motion records before dynamic analysis. • Relation of structural fundamental period and period elongation ratio is studied. • Truncated records by the duration keep structural responses almost unchanged. • The duration is the best on balancing efficiency and accuracy compared with others. [ABSTRACT FROM AUTHOR]

In the space station, filamentous fungi are one of the main potential hazards causing short circuits or corrosion failure of printed circuit boards (PCBs). A 90-day fungal corrosion test was carried out on the China Space Station (CSS), focusing on the interaction between A. brasiliensis and exposed copper circuits. The results showed that the mycelial morphology, ultrastructure, and organic acid accumulation of the test fungi exhibited significant changes in the space microgravity environment. Aspergillus brasiliensis tended to excrete higher levels of oxalic acid in space as a defense mechanism against copper toxicity, which could exacerbate localized corrosion of copper metal. • The fungal corrosion behavior of copper in space was studied for the first time. • A. brasiliensis in space tends to excrete higher levels of oxalic acid. • Significant increase in pitting depth by A. brasiliensis in space. • Acid corrosion and oxygen concentration cells may be the main corrosion mechanisms. [ABSTRACT FROM AUTHOR]

Purpose: Under the influence of loading, manufacturing, installation and other factors, the axis of sleeve bearing and journal will not be aligned, which will have a great impact on running stability and life of bearing. The existence of oil groove can effectively improve the life of sleeve bearing and working efficiency. The lubrication performance of two and three grooves sleeve bearing considering journal misalignment is analyzed. Design/methodology/approach: To solve the difference of discontinuous position of oil film thickness, it is necessary to use the flow balance relationship in the finite control space, and oil film thickness equation of multi-groove sleeve bearing considering journal misalignment is gained. Findings: The friction and bearing capacity of journal bearing with oil groove increase with the increase of journal inclination angle. At the same journal inclination angle, the bearing capacity of two-axial groove journal bearing is larger than that of three-axial groove journal bearing, but the friction of two-axial groove journal bearing shows the trend of the first bigger and then smaller than that of three-axial groove journal bearing. Originality/value: The research has great significance to optimize bearing lubrication performance and increase bearing working life. [ABSTRACT FROM AUTHOR]

Recently meta-learning-based few-shot learning methods have been widely used for relation classification. Previous work reveals that meta-learning performs poorly in scenarios where the edge probability distribution of the target domain dataset appears to be significantly different from the source domain. In this paper, we enhance the meta-learning framework with high-dimensional semantic feature extraction and hyperplane projection metrics for meta-tasks. First, we enhance the focus of BERT on entity words by adding entity markers and vector pooling. After that, the high-dimensional semantic features of the support set are extracted and transformed into hyperplanes. Finally, we obtain the classification results by calculating the projection distance between the query sample and the hyperplane. In addition, we design a auxiliary function with a plane correction factor, which can better amplify the plane spacing and reduce the degree of category confusion, which is important for solving the problem of metric spatial loss. Experiments on two real-world few-shot datasets show that our model HPN is more effective in classifying few-shot relations in the same domain and domain-adapted scenarios. And HPN is more stable on NOTA tasks. • A hyperplane projection network is proposed for few shot relation classification. • Propose an effective entity encoder that extracts better features. • First apply a novel hyperplane module to generate class-level feature. [ABSTRACT FROM AUTHOR]

• A series of bidirectional pseudo-static tests on isolated infill walls in RC frames were conducted. • The effects of the in-plane and out-of-plane on the isolated infilled frames can not be neglected. • Boundary constraints affected the in-plane and out-of-plane performance of isolated infilled walls. This paper presents the findings of a series of bidirectional quasi-static tests conducted on isolated infilled frames to investigate the in-plane and out-of-plane interaction of the infills with different boundary constraints. The effects of prior in-plane damage on the out-of-plane behavior of isolated infill walls were assessed. It was found that the presence of existing cracks that developed during the in-plane loading stage had an effect on the out-of-plane cracking patterns, decreased the integrity of the isolated infills, and weakened the infill-frame boundary restraints. The behavior of isolated infill walls under combined in-plane and out-of-plane loading was also affected by the effectiveness of boundary constraints. The experimental results demonstrated that reliable boundary constraints were necessary for forming arching mechanisms and preventing rigid body motion. [ABSTRACT FROM AUTHOR]

Abstract Tiger puffer have a unique lipid storage pattern. They store lipid predominantly in liver. To investigate the hepatic physiology of tiger puffer in response to a moderately high level of dietary lipid, a 74-day feeding trial was conducted, followed by a hepatic transcriptome assay. Two experimental diets which had an optimal (10.44%, Control) or moderately higher (14.64%, high-lipid diet, HL) dietary lipid level was formulated. Each diet was fed to triplicate tanks. No significant difference was observed in growth and feed efficiency between the two groups, but the survival was significantly lower in group HL. The HL diet also resulted in significantly higher lipid accumulation in liver, which was reflected in the hepatic histology. The biochemical parameters in serum confirmed the existence of stress in liver caused by high lipid intake. A total of 63 differentially expressed genes between groups were observed in the hepatic transcriptome assay, which were primarily enriched in Gene Ontology (GO) terms such as Endopeptidase activity, Secretion, and Organic acid transport, as well as in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as Protein processing in endoplasmic reticulum and DNA replication. The HL diet tended to inhibit the protein synthesis and secretion in liver, and this was evidenced by activities/concentrations of selected proteins secreted into intestine. Genes related to liver protection and repair were transcriptionally stimulated by diet HL. In conclusion, compared to the optimal lipid requirement, a moderately higher lipid level in the diet for tiger puffer did not compromise the growth performance, but tended to inhibit the protein secretion function of liver and stimulate the processes related to liver protection and repair. The present results will be beneficial to both feed management in tiger puffer farming and elucidation of lipid metabolism characteristics in fish which store lipid in liver. Highlights • A moderately high lipid level in diet for tiger puffer did not compromise the growth performance, but lowered the survival. • Protein secretion function is the primarily impaired liver function by a moderately high level of dietary lipid. • A moderately high level of dietary lipid tended to stimulate the processes related to liver protection and repair. • The results will be beneficial to both feed management and lipid metabolism research in fish storing lipid in liver. [ABSTRACT FROM AUTHOR]

A 3-month feeding trial with tongue sole Cynoglossus semilaevis broodstock was conducted before and during the spawning season to investigate the effects of dietary arachidonic acid (ARA) on the production of sex steroid hormones and gonadal gene expression of key proteins in steroidogenesis. Three isonitrogenous and isolipidic experimental diets were formulated to contain different ARA levels: the control diet without ARA supplementation (C, 0.58% ARA of total fatty acids (TFA)) and two diets with low (5.14% of TFA, ARA-L) or high ARA (15.44% of TFA, ARA-H) supplementation. The diets were randomly assigned to 9 tanks of 3-year-old tongue sole (10 females and 15 males in each tank). Fish were reared in a flowing seawater system and fed to apparent satiation twice daily. At the end of the feeding trial, tissue samples from mature females (MF, with spontaneous ovulation), immature females (IMF, early vitellogenesis), and mature males (MM, expressing milt) were collected to assay the production of sex steroid hormones, gonadal gene expression of sex steroid-synthesizing proteins, as well as the fatty acid profiles of gonad, liver and muscle lipids. Results showed that ARA supplementation significantly reduced the estradiol production in females, but stimulated the testosterone production in males. ARA supplementation significantly reduced the mRNA expression of aromatase in ovaries but significantly increased the gene expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) in testes. In mature ovaries, diet ARA-L significantly reduced the gene expression of follicle stimulating hormone receptor (FSHR), 3β-HSD, and 17β-HSD; however, in immature ovaries, it significantly increased the gene expression of FSHR, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450ssc), 3β-HSD, and 17β-HSD. In all gonads, 17α-hydroxylase (P450c17) responded to dietary ARA differently from other sex steroid-synthesizing proteins. ARA was preferentially accumulated in tongue sole gonad lipids. ARA concentrations were highest in gonad, liver and muscle lipids of MM fish and lowest in MF fish. Compared to female tongue sole, males had higher DHA concentrations in gonad lipids, but lower concentrations in liver lipids. In conclusion, results suggest dietary ARA regulates sex steroid hormone synthesis in tongue sole broodstock, and accumulates in gonad lipids, depending on both fish gender and maturation stage. Dietary ARA supplementation appears more important for male fish than for female fish, and more important for immature females than for mature females. Statement of relevance This study is beneficial to the broodstock diet formulation. [ABSTRACT FROM AUTHOR]

In the present study, putative cDNA of five fabp isoforms, i.e., fabp1 , fabp2 , fabp3 , fabp4 , and fabp7 , was cloned and characterized from the liver of Japanese seabass ( Lateolabrax japonicus ), and their expression in response to diets with different arachidonic acid (ARA) levels (0.05%, 0.22%, 0.37%, 0.60%, 1.38% and 2.32% of dry matter) was investigated following a feeding trial. The Japanese seabass fabp s showed high identity to their orthologs in other fish species and mammals. However, a specific fabp of Japanese seabass showed much lower identity to other Japanese seabass fabp s. fabp1 has high expressions in liver and intestine, whereas fabp2 is mainly expressed in the gastrointestinal tract. The highest expression level of fabp3 , fabp4, and fabp7 was observed in muscle, eye, and liver respectively. Different tissue expression patterns of fabp2 , fabp4, and fabp7 between Japanese seabass and other teleost may indicate specific evolutionary Fabp functions in Japanese seabass. Moderate levels of dietary ARA (0.37–0.60%) enhanced the gene expressions of fabp1 in liver and intestine, fabp2 in intestine, and fabp3 in intestine, whereas excess dietary ARA levels (1.38–2.323%) were ineffective. The highest level of dietary ARA (2.32%) increased only the expression of fabp3 in muscle compared to the control diet. Gene expressions of fabp3 and fabp7 in liver, and fabp4 in liver, intestine, and muscle were not significantly influenced by dietary ARA. To our knowledge, this is the first study investigating the regulation of fabp expressions by dietary ARA. [ABSTRACT FROM AUTHOR]

A 12-week feeding trial was conducted to evaluate the effects of dietary fish oil (FO) replacement by beef tallow (BT) on the growth performance and body composition of juvenile turbot (average initial weight, 19.6 g). The control diet contained 6% added FO (of dry matter, Diet FO-C). Beef tallow was supplemented into Diet FO-C, replacing added FO at different levels, i.e., 25%, 50%, 75%, and 100%, formulating the other 4 experimental diets, designated as 25BT, 50BT, 75BT, and 100BT, respectively. The feeding trial was conducted in a flow-through seawater system. Each diet was randomly fed to triplicate tanks (30 fish in each tank). The results showed that a cubic regression relationship was observed between weight gain and dietary FO replacement level. Although total FO replacement by BT significantly reduced the growth of juvenile turbot, no significant difference was observed between FO-C and 75BT. Diet BT decreased the whole-body crude lipid content but increased the whole-body moisture and ash contents. Dietary BT regulated the proximate composition of fish tissues in a dose dependent manner. High dietary BT levels did not reduce the n-3 long-chain polyunsaturated fatty acid content (% total fatty acid) in the muscle. Partial FO replacement (25 and 50%) by BT even significantly increased the muscle DHA content. The fatty acid composition of the liver, subcutaneous adipose tissue around the fin, and intestine generally reflected those of the diets. No significant difference was observed in muscle and liver mitochondrial DNA copy number among groups, indicating the similar general energy supply status. Dietary BT significantly reduced the concentration of triacylglycerol, cholesterol and malondialdehyde in the serum. The volatile flavor compound in muscle was analyzed with gas chromatography-ion migration spectrometry (GC-IMS). Dietary BT resulted in lower number and abundance of flavor aldehydes and alcohols in the muscle. In conclusion, beef tallow can replace 75% added fish oil (appr. 45% of total fish oil including the residual fish oil in fishmeal) in the diets of turbot, without reducing fish growth. Dietary beef tallow significantly affected the body composition and volatile flavor compound composition in the muscle. • Beef tallow can replace 75% added fish oil in turbot diets. • Partial fish oil replacement by beef tallow increased the muscle DHA content. • Dietary beef tallow resulted in lower abundance of flavor aldehydes and alcohols. • Dietary beef tallow decreased the whole-body crude lipid content. [ABSTRACT FROM AUTHOR]

A 63-day feeding trial was conducted to evaluate the effect of Clostridium autoethanogenum protein (CAP) on the growth, digestibility, postprandial free amino acid concentrations in serum, and gene expression related to protein metabolism in obscure pufferfish (Takifugu obscurus). The basal diet with 420 g/kg of fishmeal was used as the control diet (CAP0), and then 20 % (CAP20), 40 % (CAP40) and 80 % (CAP80) dietary fishmeal were replaced by CAP. Compared with diet CAP0, the growth and feed utilization was not affected in fish fed diet CAP20, but was significantly reduced in fish fed diets CAP40 and CAP80 (P < 0.05). The apparent digestibility coefficients (ADCs) of dry matter and protein in the CAP80 group were significantly lower (P < 0.05) than those of the other three groups, and the ADC of lipid was significantly decreased (P < 0.05) in the CAP40 and CAP80 groups. Fish fed diets CAP40 and CAP80 had lower taurine content in muscle compared to those fed diets CAP0 and CAP20 (P < 0.05). Higher free essential amino acid concentrations in serum were observed in fish fed diet CAP80 compared to the other diets at 2 h after refeeding (P < 0.05). Fish fed diets CAP40 and CAP80 showed lower hardness and gumminess in muscle than those fed the other diets (P < 0.05). The expression of peptide transporter1 (PepT1) in intestine and target of rapamycin (TOR) in muscle were significantly up-regulated in the CAP40 groups compared to the control (CAP0) (P < 0.05). However, relative expressions of 4F2 heavy chain (4F2hC), L-type amino acid transporter 2 (y+LAT2) and T-type amino acid transporter1(TAT1) in intestine were not significantly affected by graded levels of CAP (P > 0.05). The inclusion of CAP did not significantly affect the expression of ribosomal protein S6 kinase 1 (S6K1), eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) and 4E-BP2 (P > 0.05) in muscle and liver. In summary, in a basal diet containing 420 g/kg fishmeal, 20 % fishmeal in diets could be successfully substituted by CAP, while high-level CAP decreased the growth, feed utilization and digestibility in juvenile obscure pufferfish. The main reasons for the inhibition of growth performance were probably that excessive CAP caused dietary taurine deficiency and the imbalance of amino acid absorption. • CAP can partially substitute fishmeal without negative effects on growth and feed utilization in obscure pufferfish. • Fishmeal replacement by CAP significantly up-regulated the expressions of TOR and PepT1 at transcriptional level. • Excessive CAP may cause dietary taurine deficiency and the imbalance of amino acid absorption. [ABSTRACT FROM AUTHOR]

• A certain amount about 3%–5% of Mn can improve the SCR process of Fe 2 O 3. • Mn doping can lead the electrons migration so as to improve the surface acidity. • The doping of Mn could promote the adsorption of reactants. • The doping of Mn could reduce the energy barrier of SCR reactions. A main reaction process for NH 3 -SCR of NO over Mn doped γFe 2 O 3 catalyst NO over CuMn 2 O 4 surface [Display omitted] A certain amount about 3%–5% of Mn doping on γ-Fe 2 O 3 catalyst surface can improve the NO removal catalytic activity. However, the mechanism of Mn doping to improve the de-NO x catalytic activity is still unclear. In this paper, the doping of Mn on γ-Fe 2 O 3 (001) surface was optimized, and the adsorption behavior of reactants as well as the reaction pathway were studied by the density functional theory (DFT). The results show that the doping of Mn on γ-Fe 2 O 3 (001) surface can lead to the migration of electrons, so as to improve the surface acidity and activity. It can promote the adsorption of NH 3 and NO on the surface. On the other hand, the NH 3 molecule can be adsorbed and dehydrogenated and the NH 2 is the most important product and the process of NH 2 formation is the rate determining step. Compared with undoped catalysts, the step is easier to be completed because it has lower energy barrier. The next main step is the reaction between NH 2 and NO to produce NH 2 NO, and then decomposes to N 2 and H 2 O. These steps are also easier to be achieved than undoped catalysts. Therefore, doping of Mn on γ-Fe 2 O 3 catalyst surface can improve the NO removal catalytic activity. [ABSTRACT FROM AUTHOR]

Use of terrestrially sourced oil (TSO) in fish diets easily causes adverse effects on fillet quality. The present study, with turbot, was aimed at evaluating the efficacy of alternate feeding between fish oil (FO)- and TSO-based diets in minimizing these adverse effects. The control group were fed the FO-based diet continuously for 13 weeks, meanwhile other groups were subjected to weekly alternation between the FO-based diet and diets based on TSO, namely, linseed oil, soybean oil, rapeseed oil, palm oil, and beef tallow, respectively. The feeding trial was conducted in a flow-through seawater system. Each group had triplicate tanks, and each tank was stocked with 35 fish. Samples were collected at the end of Week 9 and 13. At Week 9, no significant difference among groups was observed in growth performance and muscle proximate composition, texture, and odour-active compound profile; however significant differences were observed in muscle content of long-chain polyunsaturated fatty acids, serum malondialdehyde content, and somatic indices. These differences disappeared at Week 13. In conclusion, long-term alternation between FO- and TSO-based diets could mitigate the adverse effects of TSO on farmed turbot. Unlabelled Image • Terrestrially sourced oil (TSO) in fish diets easily causes adverse effects. • Alternate feeding between fish oil and TSO prevented changes in growth. • Alternate feeding prevented changes in muscle texture and odour-active compounds. • Long-term alternate feeding prevented changes in muscle LC-PUFA. [ABSTRACT FROM AUTHOR]

Bile acid (BA) plays an important role in lipid metabolism. Tiger puffer has a unique lipid storage pattern; storing lipid predominantly in the liver. The present study aimed to investigate the effects of dietary BA supplementation on hepatic lipid accumulation and metabolism in tiger puffer fed normal or high-lipid diets. An 8-week feeding trial was conducted in an indoor flow-through seawater system. Two diets with suitable (8.5%, diet C) or high lipid level (12.5%, diet HL) were prepared. BA, a porcine bile extract mainly comprised of hyodeoxycholic acid was supplemented into the two diets at the level of 0.02% to formulate diet CBA and diet HLBA, respectively. A fifth diet was prepared by supplementing an excess level of porcine bile extract (0.10%) into diet C (diet CHBA). Each diet was randomly fed to triplicate tanks. Dietary BA supplementation did not significantly affect fish growth performances. Dietary BA tended to decrease the whole-body lipid content, liver lipid content, hepatosomatic index, and viscerasomatic index in both fish fed with normal diets and fish fed with high-lipid diets. Similar results were observed for the contents of triacylglycerol, total cholesterol, and low-density lipoprotein-cholesterol in serum. The quantitative bile acid metabolomics analysis showed that taurocholic acid and taurochenodeoxycholic acid were dominantly abundant in the gallbladder. Dietary BA supplementation increased the concentration of taurohyodeoxycholic acid, glycohyodeoxycholic acid, and glycocholic acid, but affected some other BAs in various patterns. Dietary BA regulated hepatic transcription of lipid metabolism-related genes differentially in fish fed normal diets and fish fed high-lipid diets, decreasing the transcription of lipogenic genes in fish fed normal diets but increasing the transcription of genes related to lipid digestion and lipid/cholesterol transport in fish fed high-lipid diets. In conclusion, dietary BA supplementation tended to reduce the lipid accumulation in juvenile tiger puffer. However, at the transcription level the regulation of lipid metabolism by dietary BA seemed very different between fish fed normal diets and fish fed high-lipid diets. This study contributes to the general knowledge of bile physiology under different nutritional conditions in teleost and is beneficial to lipid management in tiger puffer farming. • Dietary bile acid tended to decrease hepatic lipid accumulation and serum triacylglycerol and cholesterol levels. • Dietary bile acid increased the contents of taurochenodeoxycholic acid and taurohyodeoxycholic acid in the gallbladder. • Dietary bile acid regulates gene transcription differentially in fish fed normal diets and fish fed high-lipid diets. • Dietary bile acid decreased the transcription of lipogenic genes only in fish fed normal diets. [ABSTRACT FROM AUTHOR]

Vibrio genus is a common pathogen in aquaculture and causes acute hepatopancreatic necrosis disease (AHPND) and massive mortality of shrimp. Many studies have suggested that a single functional ingredient such as plant extract or organic acid can reduce the dependence on antibiotics and promote the growth and immunity of aquatic animals. In this study, we evaluated the effects of a phytobiotic-based compound additive (Sanacore® GM, SNGM), which had a successful trajectory of commercial application in fish farming. However, its effects on the hepatopancreas health and intestinal microbiota of shrimp after Vibrio challenge have not been well evaluated. In the present study, Pacific white shrimp were fed diets with or without supplementation of SNGM, and the SNGM grades were 0-g/kg (CON), 3-g/kg (SNGM3), and 5-g/kg (SNGM5) diets. The feed trial lasted 60 days, after which a Vibrio parahaemolyticus challenge was performed. The results showed that compared to the CON group, both the SNGM3 and SNGM5 groups had a significantly higher weight gain and a lower feed conversion ratio as well as higher survival after Vibrio parahaemolyticus challenge. In the growth trial, the SNGM3 group had a significantly increased total protein, albumin concentration, and acid phosphatase activity in hemolymph compared to the CON group. In the challenge experiment, the SNGM3 and SNGM5 groups had increased albumin and glucose contents as well as the activities of phenoloxidase, lysozyme, alkaline phosphatase, and superoxide dismutase in hemolymph. Both the SNGM3 and SNGM5 groups had improved morphology of the hepatopancreas and intestine. The SNGM5 group had alleviated gut microbiota dysbiosis induced by Vibrio infection by increasing the potential probiotic bacterium abundance ( Shewanella ) and decreasing the potential pathogenic bacteria abundance ( Vibrio , Photobacteriuma , Pseudoalteromonas , and Candidatus&#95;Bacilloplasma ). In conclusion, the dietary phytobiotic-based additive at 3-g/kg level increased the growth and Vibrio parahaemolyticus resistance of Pacific white shrimp by promoting immune-related enzyme activities and improving the morphological structure of the hepatopancreas and intestine and the intestinal microbiota composition., Competing Interests: Authors GZ, I-TC, and WN-O were employed by the company Adisseo Life Science Shanghai Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ma, Zhao, Liu, Chen, Wei, Liang, Dai, Nuez-Ortin and Xu.)

Astaxanthin (AST), functioning as an efficient antioxidant and pigment, is one of the most expensive additives in shrimp feeds. How to improve the uptake efficiency of dietary astaxanthin into farmed shrimp is of significance. The present study investigated the effects of lysophosphatidylcholine (LPC), an emulsifier, on dietary astaxanthin efficiency, growth performance, body color, body composition, as well as lipid metabolism of juvenile Pacific white shrimp (average initial body weight: 2.4 g). Three diets were prepared: control group, the AST group (supplemented with 0.02% AST), and the AST + LPC group (supplemented with 0.02% AST and 0.1% LPC). Each diet was fed to triplicate tanks, and each tank was stocked with 30 shrimp. The shrimp were fed four times daily for eight weeks. The AST supplementation improved the growth of white shrimp, while LPC further promoted the final weight of shrimp, but the whole-shrimp proximate composition and fatty acid composition were only slightly affected by AST and LPC. The LPC supplementation significantly increased the astaxanthin deposition in the muscle. The LPC supplementation significantly increased the shell yellowness of both raw and cooked shrimp compared to the AST group. Moreover, the dietary LPC increased the high-density lipoprotein-cholesterol content but decreased the low-density lipoprotein-cholesterol content in the serum, indicating the possible regulation of lipid and cholesterol transport. The addition of astaxanthin significantly up-regulated the expression of npc2 in the hepatopancreas compared to the control group, while the addition of LPC down-regulated the expression of mttp compared to the AST group. In conclusion, the LPC supplementation could facilitate the deposition of dietary astaxanthin into farmed shrimp and further enlarge the beneficial effects of dietary astaxanthin. LPC may also independently regulate shrimp body color and cholesterol transportation. This was the first investigation of the promoting effects of LPC on dietary astaxanthin efficiency.

Acute hypoxia is a common stress in aquaculture, and causes energy deficiency, oxidative damage and death in fish. Many studies have confirmed that acute hypoxia activated hif1α expression, anaerobic glycolysis and antioxidant system in fish, but the effects of acute hypoxia on lipid and protein metabolism, organelle damage, and the functions of hif2α and hif3α in economic fishes have not been well evaluated. In the present study, turbot was exposed to acute hypoxia (2.0 ± 0.5 mg/L) for 6 h, 12 h, and 24 h, respectively. Then, the contents of hemoglobin (HB), metabolite, gene expressions of hifα isoforms, energy homeostasis, endoplasmic reticulum (ER) stress, and apoptosis were measured. The results suggested that turbot is intolerant to acute hypoxia and the asphyxiation point is about 1.5 mg/L. Acute hypoxia induced perk-mediated ER stress, and increased lipid peroxidation and liver injury in turbot. The blood HB level and liver vegfab expression were increased under hypoxia, which enhances oxygen transport. At hypoxia stress, hif3α, anaerobic glycolysis-related genes expression, and lactate content were increased in the liver, and glycogen was broken down to ensure ATP supply. Meanwhile, hif2α, lipid synthesis-related genes expression, and TG content were increased in the liver, but the lipid catabolism and protein synthesis were suppressed during hypoxia, which reduced the oxygen consumption and ROS generation. Our results systematically illustrate the metabolic and physiological changes under acute hypoxia in turbot, and provide important guidance to improve hypoxia tolerance in fish., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

The objective of this study was to investigate the potential effect of graded levels of tryptophan on the growth, cannibalism, and 5-hydroxytryptpamine (5-TH) metabolism in pufferfish ( Takifugu obscurus ♀ ×  Takifugu rubripes ♂). A 63-day feeding trial was performed wherein pufferfish were fed four diets. Three experimental diets were formulated with various levels of tryptophan based on the control diet. Four diets were named as T1, T2, T3, and T4, corresponding to 4.30, 7.80, 14.90, and 23.70 g kg -1 tryptophan of dry diet. Final body weight, weight gain, and specific growth rate were similar between the T1 and T4 groups, but exhibited a significantly increased trend compared to the T2 group. Although survival rate was not affected by various levels of dietary tryptophan, intraspecific cannibalism was significantly reduced in the group fed with highest level of tryptophan (T4). For free amino acid in brain, the concentration of tryptophan was the highest in the T3 group and the lowest in the T2 group, while phenylalanine, tyrosine, and methionine showed an opposite trend between those two groups. The levels of dietary tryptophan not only affected the expression of aromatic amino acid transporter TAT1, but also affected the expression of B0AT1, B0AT2, and 4F2hc in intestine, as well as B0AT1, y + LAT1, and LAT2 in brain. The activity of tryptophan hydroxylase (TPH) in serum increased with the increase of dietary tryptophan, and the expression of TPH1 in brain upregulated in the excessive tryptophan groups (T2, T3, and T4). MAO activity in serum as well as its gene expression in brain and intestine showed a decreased trend in the T4 group. In conclusion, excessive tryptophan (23.70 g kg -1 of dry diet, corresponding to 50.3 g kg -1 of dietary protein) in feed could mitigate cannibalistic behavior of pufferfish and promote the growth, and the reason for this effect might affect the metabolism of 5-TH in vivo ., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2023 Yuliang Wei et al.)

Difluorocarbene-triggered [1+5] annulation is developed to access 1,1-difluoro-1,9a-dihydropyrido[2,1- c ][1,4]thiazine-3,4-dicarboxylate derivatives in satisfactory to good yields via the direct reaction of potassium bromodifluoroacetate and pyridinium 1,4-zwitterionic thiolates under heating. Pyridinium 1,4-zwitterionic thiolates first nucleophilically attack difluorocarbene generated from potassium bromodifluoroacetate followed by an intramolecular nucleophilic addition to pyridiniums. This method provides an expeditious route to introduce the difluoromethyl group into the 1,9a-dihydropyrido[2,1- c ][1,4]thiazine ring, even to modify drug molecules.

Booming fish farming results in a relative shortage of fish oil (FO) supply, meaning that alternative oils are increasingly used in fish feeds, which leads to reduction of long-chain polyunsaturated fatty acids (LC-PUFAs) and other relevant changes in fish products. This study investigated the efficacy of an FO-finishing strategy in recovering the muscle quality of farmed tiger puffer. An eight-week feeding trial (growing-out period) was conducted with five experimental diets, in which graded levels (0 (control), 25, 50, 75, and 100%) of added FO were replaced by poultry oil (PO). Following the growing-out period was a four-week FO-finishing period, during which fish in all groups were fed the control diet. Dietary PO significantly decreased the muscle LC-PUFA content, whereas in general, the FO-finishing strategy recovered it to a level comparable with that of the group fed FO continuously. The recovery efficiency of EPA was higher than that of DHA. Dietary PO also led to changes of volatile flavor compounds in the muscle, such as butanol, pentenal, and hexenal, whereas the FO-finishing strategy mitigated the changes. In conclusion, the FO-finishing strategy is promising in recovering the LC-PUFA and volatile-flavor-compound composition in farmed tiger puffer after the feeding of PO-based diets.

Chemoselective annulations of phosphoryl carbenes generated from diazo(aryl)methyl(diaryl)phosphine oxides with pyridinium 1,4-zwitterionic thiolates were performed under microwave irradiation, affording 1-diarylphosphoryl-1 H -benzo[ c ]thiopyran derivatives via [3+3] annulation and indolizine derivatives via ([1+5]-1) annulation with P-Cope elimination as the key step. The annuloselectivity was controlled by the steric hindrance of pyridiniums in pyridinium 1,4-zwitterionic thiolates.

Iron-based catalysts have been explored for selective catalytic reduction (SCR) of NO due to environmentally benign characters and good SCR activity. Mn-W-Sb modified siderite catalysts were prepared by impregnation method based on siderite ore, and SCR performance of the catalysts was investigated. The catalysts were analyzed by X-ray diffraction, H 2 -temperature-programmed reduction, Brunauer-Emmett-Teller, Thermogravimetry-derivative thermogravimetry and in-situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS). The modified siderite catalysts calcined at 450°C mainly consist of Fe 2 O 3 , and added Mn, W and Sb species are amorphous. 3Mn-5W-1.5Sb-siderite catalyst has a wide temperature window of 180-360°C and good N 2 selectivity at low temperatures. In-situ DRIFTS results show NH 4 + , coordinated NH 3 , NH 2 , NO 3 - species (bidentate), NO 2 - species (nitro, nitro-nitrito, monodentate), and adsorbed NO 2 can be discovered on the surface of Mn-W-Sb modified siderite catalysts, and doping of Mn will enhance adsorbed NO 2 formation by synergistic catalysis with Fe 3+ . In addition, the addition of Sb can inhibit sulfates formation on the surface of the catalyst in the presence of SO 2 and H 2 O. Time-dependent in-situ DRIFTS studies also indicate that both of Lewis and Brønsted acid sites play a role in SCR of NO by ammonia at low temperatures. The mechanism of NO removal on the 3Mn-5W-1.5Sb-siderite catalyst can be discovered as a combination of Eley-Rideal and Langmuir-Hinshelwood mechanisms with three reaction pathways. The mechanism of NO, oxidized by synergistic catalysis of Fe 3+ and Mn 4+/3+ to form NO 2 among three pathways, reveals the reason of high NO x conversion of the catalyst at medium and low temperatures., (Copyright © 2021. Published by Elsevier B.V.)

The present study was aimed at screening suitable reference genes for quantitative real-time polymerase chain reaction (qRT-PCR) in tiger puffer (Takifugu rubripes), an important aquaculture species in Asia and also a good model species for lipid research. Specifically, this reference gene screening was targeted at standardization of gene expression in different tissues (liver, muscle, brain, intestine, heart, eye, skin, and spleen) or under different nutritional conditions (starvation and different dietary lipid levels). Eight candidate reference genes (ribosomal protein L19 and L13 (RPL19 and RPL13), elongation factor-1 alpha (EF1α), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hypoxanthine guanine phosphoribosyl transferase1 (HPRT1), beta-2-Microglobulin (B2M), 18S ribosomal RNA (18SrRNA), and beta actin (ACTB)) were evaluated with four algorithms (geNorm, NormFinder, BestKeeper, and comparative ΔCt method). The results showed that different algorithms generated inconsistent results. Based on these findings, RPL19, EF1α, 18SrRNA, and RPL13 were relatively stable in different tissues of tiger puffer. During starvation conditions, ACTB/RPL19 was the best reference gene combination. Under different dietary lipid levels, ACTB/RPL13 was the most suitable reference gene combination. The present results will help researchers to obtain more accurate results in future qRT-PCR analysis in tiger puffer., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

The tissue distribution pattern of lipid is highly diverse among different fish species. Tiger puffer has a special lipid storage pattern, storing lipid predominantly in liver. In order to better understand the lipid physiology in fish storing lipid in liver, the present study preliminarily investigated the tissue distribution of transcription for 29 lipid metabolism-related genes in tiger puffer, which are involved in lipogenesis, fatty acid oxidation, biosynthesis and hydrolysis of glycerides, lipid transport, and relevant transcription regulation. Samples of eight tissues, brain, eye, heart, spleen, liver, intestine, skin, and muscle, from fifteen juvenile tiger puffer were used in the qRT-PCR analysis. The intestine and brain had high transcription of lipogenic genes, whereas the liver and muscle had low expression levels. The intestine also had the highest transcription level of most apolipoproteins and lipid metabolism-related transcription factors. The transcription of fatty acid β-oxidation-related genes was low in the muscle. The peroxisomal fatty acid oxidation may dominate over mitochondrial β-oxidation in the liver and intestine of tiger puffer, and the MAG pathway probably predominates over the G3P pathway in re-acylation of absorbed lipids in the intestine. The intracellular glyceridases were highly transcribed in the brain, eye, and heart. In conclusion, in tiger puffer, the intestine could be a center of lipid metabolism whereas the liver is more likely a pure storage organ for lipid. The lipid metabolism in the muscle could also be inactive, possibly due to the very low level of intramuscular lipid.