Slow Absorption of Conjugated Linoleic Acid in Rat Intestines,and Similar Absorption Rates of 9c,11t-Conjugated Linoleic Acid and 10t,12c-Conjugated Linoleic Acid

We have previously shown that the 9c,11t-conjugated linoleic acid (CLA) concentration was always significantly higher than the 10t,12c-CLA concentration following the administration of these compounds to mice and rats, and considered that structural differences between the conjugated double bonds in these isomers affected absorption in the small intestine. This study investigates the absorption of CLA in the rat intestine by a lipid absorption assay of lymph from the thoracic duct. In Study 1, we used safflower oil and a triacylglycerol form of CLA (CLA-TG), while in Study 2, we used 9c,11t-CLA and 10t,12c-CLA. The cumulative recovery of CLA was lower than that of linoleic acid until two hours after sample administration. There was no difference in the extent of lymphatic recovery of 9c,11t-CLA and 10t,12c-CLA after the administration of CLA-TG, 9c,11t-CLA, and 10t,12c-CLA to the rats, suggesting that geometrical and positional isomerism of the conjugated double bonds did not influence the absorption.     

A Novel Therapy for Melanoma Developed in Mice: Transformation of Melanoma into Dendritic Cells with Listeria monocytogenes

Listeria monocytogenes is a gram-positive bacteria and human pathogen widely used in cancer immunotherapy because of its capacity to induce a specific cytotoxic T cell response in tumours. This bacterial pathogen strongly induces innate and specific immunity with the potential to overcome tumour induced tolerance and weak immunogenicity. Here, we propose a Listeria based vaccination for melanoma based in its tropism for these tumour cells and its ability to transform in vitro and in vivo melanoma cells into matured and activated dendritic cells with competent microbicidal and antigen processing abilities. This Listeria based vaccination using low doses of the pathogen caused melanoma regression by apoptosis as well as bacterial clearance. Vaccination efficacy is LLO dependent and implies the reduction of LLO-specific CD4⁺ T cell responses, strong stimulation of innate pro-inflammatory immune cells and a prevalence of LLO-specific CD8⁺ T cells involved in tumour regression and Listeria elimination. These results support the use of low doses of pathogenic Listeria as safe melanoma therapeutic vaccines that do not require antibiotics for bacterial removal.     

Incorporation and metabolism of c9,t11 and t10,c12 conjugated linoleic acid (CLA) isomers in rat brain

Conjugated linoleic acid (CLA) has been shown to exert several biological activities in different organs, in particular organs such as adipose and mammary tissue where CLA accumulates preferentially because of its high incorporation into neutral lipids. However, despite numerous studies carried out in different experimental models, both in vivo and in vitro, very little is known about the accumulation and metabolism of CLA in the brain. In this communication we present data showing that the two CLA isomers c9,t11 and t10,c12 are actively incorporated and metabolised in rat brain, and in cultures of astrocytes in vitro with patterns remarkably similar to those previously reported to occur in other tissues and cells. However, beta oxidation of CLA was found to be more efficient in brain than in other tissues, with t10,c12 a better substrate than the c9,t11 isomer. CLA incorporation and metabolism have been linked to antiinflammatory and antiproliferative activities in experimental models. Therefore, CLA activity in brain could have a positive impact on neurological disorders, such as Alzheimer's disease, Parkinson's disease and adrenoleukodystrophy, where an observed increase in inflammatory responses seems to contribute heavily to the pathogenesis.     

A Gut Microbial Metabolite of Linoleic Acid, 10-Hydroxy-cis-12-octadecenoic Acid,Ameliorates Intestinal Epithelial Barrier Impairment Partially via GPR40-MEK-ERK Pathway

Gut microbial metabolites of polyunsaturated fatty acids have attracted much attention because of their various physiological properties. Dysfunction of tight junction (TJ) in the intestine contributes to the pathogenesis of many disorders such as inflammatory bowel disease. We evaluated the effects of five novel gut microbial metabolites on tumor necrosis factor (TNF)-α-induced barrier impairment in Caco-2 cells and dextran sulfate sodium-induced colitis in mice. 10-Hydroxy-cis-12-octadecenoic acid (HYA), a gut microbial metabolite of linoleic acid, suppressed TNF-α and dextran sulfate sodium-induced changes in the expression of TJ-related molecules, occludin, zonula occludens-1, and myosin light chain kinase. HYA also suppressed the expression of TNF receptor 2 (TNFR2) mRNA and protein expression in Caco-2 cells and colonic tissue. In addition, HYA suppressed the protein expression of TNFR2 in murine intestinal epithelial cells. Furthermore, HYA significantly up-regulated G protein-coupled receptor (GPR) 40 expression in Caco-2 cells. It also induced [Ca²⁺]_i responses in HEK293 cells expressing human GPR40 with higher sensitivity than linoleic acid, its metabolic precursor. The barrier-recovering effects of HYA were abrogated by a GPR40 antagonist and MEK inhibitor in Caco-2 cells. Conversely, 10-hydroxyoctadacanoic acid, which is a gut microbial metabolite of oleic acid and lacks a carbon-carbon double bond at Δ12 position, did not show these TJ-restoring activities and down-regulated GPR40 expression. Therefore, HYA modulates TNFR2 expression, at least partially, via the GPR40-MEK-ERK pathway and may be useful in the treatment of TJ-related disorders such as inflammatory bowel disease.     

Biological activities of conjugated fatty acids: conjugated eicosadienoic (conj. 20:2delta(c11,t13/t12,c14)), eicosatrienoic (conj. 20:3delta(c8,t12,c14)), and heneicosadienoic (conj. 21:2delta(c12,t14/c13,t15)) acids and other metabolites of conjugated linoleic acid

The elongated form of conjugated linoleic acid (CLA), conjugated eicosadienoic acid (CEA, conj. 20:2delta(c11,t13/t12,c14)), was generated from CLA by liver microsomal fractions. Subsequent testing showed that dietary CEA significantly reduced body fat, and increased lean mass similar to CLA when compared to controls. CEA also decreased lipoprotein lipase activity and triacylglyceride, and increased glycerol release in 3T3-L1 adipocytes, correlated with the trans-12,cis-14 isomer, but CEA required a longer incubation period than cells treated with CLA. Based on the fact that CEA fed animals had CLA in tissue, we suggest that the effect of CEA is due to the CLA converted from CEA in the system. The delta-6 desaturated and elongated form of trans-10,cis-12 CLA (conjugated eicosatrienoic acid, CETA, conj. 20:3delta(c8,t12,c14)) inhibited LPL activity and increased glycerol release but was less active than trans-10,cis-12 CLA or CEA. The 21-carbon conjugated fatty acid, conjugated heneicosadienoic acid (CHDA, conj. 21:2delta(c12,t14/c13,t15)), was not active on LPL inhibition, triacylglyceride, or glycerol release in 3T3-L1 adipocytes. We also provide evidence that CLA was metabolized to conjugated dodecadienoic acid (conj. 12:2delta(c3,t5/t4,c6)). In addition, there were indications of the presence of conjugated tetradecadienoic acid (conj. 14:2delta(c5,t7/t6,c8)), suggesting that CLA can be metabolized through fatty acid beta-oxidation. This is the first work to report the presence of conjugated 12 and 14 carbon fatty acids, originated from CLA, and the biological activities of CEA, CETA and CHDA.     

Cytotoxic effects of the conjugated linoleic acid isomers t10c12, c9t11-CLA and mixed form on rat hepatic stellate cells and CCl4-induced hepatic fibrosis

Rat hepatic stellate cells (HSC-T6) were incubated for 24 h with 10-180 microM of t10c12 (98%), c9t11 (96%) and a mixed form (c9,t11:t10,c12; 41%:44%) of conjugated linoleic acid (CLA). The MTS dye reduction was measured to verify cell viability in a dose-dependent manner. Among the three CLAs, c9,t11-CLA exhibited the most intense cytotoxic effect on HSCs, the survival rate of which was reduced to 60% under 80 microM of treatment, while cell survival was slightly affected by the mixed form. Three CLA-induced cell deaths were determined by measuring DNA fragmentation using 4',6-diamidino-2-phenylindole staining. The degrees of DNA fragmentation were the most severe in HSC treated with 80 microM of c9,t11-CLA. The mitogen-activated protein kinase/extracellular signal-regulated kinase-kinase and mitogen-activated or extracellular signal-regulated protein kinase (MEK) 1 and 2 were not activated in the t10,c12-CLA treatment. This suggests that the MEK-dependent apoptosis signal is crucial in HSC, which is induced by c9,t11 and mixed CLA. In order to evaluate the protective effect of CLA on carbon tetrachloride (CCl4)-induced hepatic fibrosis in vivo, animals were treated with 10% CCl4 to induce hepatic fibrosis during all experimental periods. Rats were divided into two treatment groups: (1) control diet with tap water ad libitum (n=15) and (2) 1% CLA diet with tap water ad libitum (n=15). In the CLA-supplemented rat livers, alpha-smooth muscle actin-positive cells were significantly reduced around the portal vein. In addition, collagen fibers were not detected in the CLA-treated group. These results suggest that 9c,11t-CLA influences cytotoxic effect on HSC in an MEK-dependent manner and preserving liver from fibrosis.     

Fatty acid composition of porcine cumulus oocyte complexes (COC) during maturation: effect of the lipid modulators trans-10, cis-12 conjugated linoleic acid (t10,c12 CLA) and forskolin

The effect of maturation and of two lipid modulators supplementation along in vitro maturation (IVM) on fatty acid (FA) and dimethylacetal (DMA) composition of porcine cumulus oocyte complexes (COC) were studied. Abattoir-derived immature COC were analyzed for FA and DMA or submitted to IVM as follows: control group; t10,c12 CLA group, t10,c12 CLA supplementation for 44 h; Forskolin group, forskolin supplementation during the initial 2 h; t10,c12 CLA?+?forskolin group, t10,c12 CLA for 44 h and forskolin for just 2h. Each experimental group had five replicates. FA analysis of oocytes, cumulus cells (CC), follicular fluid, and culture media were performed by gas–liquid chromatography. Oocytes and their CC had different FA composition. Oocytes were richer in saturated FA (SFA) preferentially maintaining their FA profile during maturation. Mature CC had the highest polyunsaturated FA (PUFA) content. Five individual and total SFA, and monounsaturated FA (MUFA), notably oleic acid (c9-18:1), percentages were lower (P?≤?0.023) in mature than in immature CC. t10,c12 CLA was accumulated by COC from t10,c12 CLA and t10,c12 CLA?+?forskolin groups, mostly in CC where MUFA and an eicosatrienoic isomer decreased (P?≤?0.043). Nevertheless, PUFA or FA and DMA total content were not affected. Arachidonic acid was reduced in t10,c12 CLA?+?forskolin CC and hexadecanal-DMA-16:0 in t10,c12 CLA CC. Forskolin alone increased (P?≤?0.043) c9-18:1 in oocytes. In conclusion, maturation process clearly changed porcine COC FA and DMA profiles, mostly of CC, also more susceptible to modifications induced by t10,c12 CLA. This possibility of manipulating COC lipid composition during IVM could be used to improve oocyte quality/cryopreservation efficiency.     

Slow absorption of conjugated linoleic acid in rat intestines, and similar absorption rates of 9c,11t-conjugated linoleic acid and 10t,12c-conjugated linoleic acid

We have previously shown that the 9c,11t-conjugated linoleic acid (CLA) concentration was always significantly higher than the 10t,12c-CLA concentration following the administration of these compounds to mice and rats, and considered that structural differences between the conjugated double bonds in these isomers affected absorption in the small intestine. This study investigates the absorption of CLA in the rat intestine by a lipid absorption assay of lymph from the thoracic duct. In Study 1, we used safflower oil and a triacylglycerol form of CLA (CLA-TG), while in Study 2, we used 9c,11t-CLA and 10t,12c-CLA. The cumulative recovery of CLA was lower than that of linoleic acid until two hours after sample administration. There was no difference in the extent of lymphatic recovery of 9c,11t-CLA and 10t,12c-CLA after the administration of CLA-TG, 9c,11t-CLA, and 10t,12c-CLA to the rats, suggesting that geometrical and positional isomerism of the conjugated double bonds did not influence the absorption.     

Regulation of Amino Acid Uptake into Oat Mesophyll Cells: A Comparison between Protoplasts and Leaf Segments

The uptake of -aminoisobutyric acid (AIB) into protoplasts andinto 1 cm sections of leaves from 7 d old light-grown oats (Avenasativa L. cv. ‘Garry’) was studied. Both protoplastsand leaf sections with cuticle and epidermis removed accumulatedAIB against a concentration gradient although the rate of uptakeinto protoplasts was one-third to one-sixth that into leaf sections.AIB uptake into both protoplasts and leaf cells in situ wasstimulated by ‘aging,’ and low pH, and inhibitedby osmotic shock, respiratory poisons, and KCl concentrationsabove 1 mM. It was concluded that the rate of uptake of AIBand its accumulation ratio could be accounted for by the energyinherent in the proton-motive force, the proton-motive forcebeing the sum of the pH gradient and potential difference acrossthe plasma membrane. The similarities between oat mesophyllprotoplasts and leaf cells in situ suggest that these protoplastsare suitable material for the study of certain membrane-regulatedevents.     

12-Lipoxygenase in A431 Cells: Genetic Identity, Modulation of Expression, and Intracellular Localization

Human A431 epidermoid carcinoma cells express 12-lipoxygenase enzymatic activity. However, the isoform identity based on cDNA sequence data is not known. Further, the simultaneous characterization of the intracellular distribution of 12-lipoxygenase protein and activity is lacking. Here we report that the cDNA sequence from RT-PCR-amplified 12-lipoxygenase mRNA is identical with the platelet-type 12-lipoxygenase isoform, and the leukocyte-type isoform of 12-lipoxygenase is not expressed in A431 cells. The predominant amount (78%) of 12-lipoxygenase protein resides in the cytosol. In contrast, the predominant (98%) 12-lipoxygenase activity is localized in the membrane fraction. Western blot and immunofluorescence data demonstrate that epidermal growth factor increases total cellular 12-lipoxygenase protein and enhances the association of 12-lipoxygenase protein with perinuclear or nuclear membrane sites. In addition, epidermal growth factor stimulates 12-lipoxygenase activity resulting in generation of 12(S)-hydroxyeicosatetraenoic acid from cellular arachidonate. In contrast, both 12-lipoxygenase protein and activity decrease approximately 80% within 24 h during serum starvation. The recovery of 12-lipoxygenase expression in serum-deprived cells can be induced by readdition of epidermal growth factor or serum. Further, the basal expression of 12-lipoxygenase depends on signal pathways requiring protein tyrosine kinase activity, since genistein, herbimycin A, and tyrphostin 25 reduce the expression of 12-lipoxygenase protein in A431 cells.     

Lipid,Fatty Acid and Energy Density Profiles of White Sharks: Insights into the Feeding Ecology and Ecophysiology of a Complex Top Predator

Lipids are major sources of metabolic energy in sharks and are closely linked to environmental conditions and biological cycles, such as those related to diet, reproduction and migration. In this study, we report for the first time, the total lipid content, lipid class composition and fatty acid profiles of muscle and liver tissue of white sharks, Carcharodon carcharias, of various lengths (1.5–3.9 m), sampled at two geographically separate areas off southern and eastern Australia. Muscle tissue was low in total lipid content (<0.9% wet mass, wm) and was dominated by phospholipids (>90% of total lipid) and polyunsaturated fatty acids (34±12% of total fatty acids). In contrast, liver was high in total lipid which varied between 51–81% wm and was dominated by triacylglycerols (>93%) and monounsaturated fatty acids (36±12%). With knowledge of total lipid and dry tissue mass, we estimated the energy density of muscle (18.4±0.1 kJ g⁻¹ dm) and liver (34.1±3.2 kJ g⁻¹ dm), demonstrating that white sharks have very high energetic requirements. High among-individual variation in these biochemical parameters and related trophic markers were observed, but were not related to any one biological or environmental factor. Signature fatty acid profiles suggest that white sharks over the size range examined are generalist predators with fish, elasmobranchs and mammalian blubber all contributing to the diet. The ecological applications and physiological influences of lipids in white sharks are discussed along with recommendations for future research, including the use of non-lethal sampling to examine the nutritional condition, energetics and dietary relationships among and between individuals. Such knowledge is fundamental to better understand the implications of environmental perturbations on this iconic and threatened species.     

The Effect of a Monoclonal Antibody Coupled to Ricin A Chain-Derived Peptides on Endothelial Cells in Vitro: Insights into Toxin-Mediated Vascular Damage

Immunotoxins (ITs) containing plant or bacterial toxins have a dose-limiting toxicity of vascular leak syndrome (VLS) in humans. The active A chain of ricin toxin (RTA), other toxins, ribosome-inactivating proteins, and the VLS-inducing cytokine IL-2 contain the conserved sequence motif (x)D(y) where X = L, I, G, or V and Y = V, L, or S. RTA-derived LDV-containing peptides attached to a monoclonal antibody, RFB4, induce endothelial cell (EC) damage in vitro and vascular leak in two animal models in vivo. We have now investigated the mechanism(s) by which this occurs and have found that (1) the exposed D75 in the LDV sequence in RTA and the C-terminal flanking threonine play critical roles in the ability of RFB4-conjugated RTA peptide to bind to and damage ECs and (2) the LDV sequence in RTA induces early manifestations of apoptosis in HUVECs by activating caspase-3. These data suggest that RTA-mediated inhibition of protein synthesis (due to its active site) and apoptosis (due to LDV) may be mediated by different portions of the RTA molecule. These results suggest that ITs prepared with RTA mutants containing alterations in LDVT may kill tumor cells in vivo in the absence of EC-mediated VLS.     

Taxonomic Status and Molecular Systematics of an Endemic Fish,Herklotsichthys lossei (Clupeidae) from the Persian Gulf: Insights into Non-monophyly of the Genus

Journal of Ichthyology - The endemic Persian Gulf herring, Herklotsichthys lossei, has similar characteristics with other congeners, especially H. punctatus, which makes it difficult to recognize....     

A Maternal High Fat Diet Programmes Endothelial Function and Cardiovascular Status in Adult Male Offspring Independent of Body Weight,Which is Reversed by Maternal Conjugated Linoleic Acid (CLA) Supplementation

Maternal high fat intake during pregnancy and lactation can result in obesity and adverse cardio-metabolic status in offspring independent of postnatal diet. While it is clear that maternal high fat intake can cause hypertension in adult offspring, there is little evidence regarding the role of dietary interventions in terms of reversing these adverse effects. Conjugated linoleic acid (CLA) is an omega 6 fatty acid with beneficial effects in obesity and metabolic status. However, the impact of CLA supplementation in the context of pregnancy disorders and high fat diet-induced developmental programming of offspring cardio-metabolic dysfunction has not been investigated. We have utilised a model of maternal overnutrition to examine the effects of CLA supplementation on programmed endothelial dysfunction during adulthood. Female Sprague-Dawley rats were fed either a purified control diet (CON) or purified control diet supplemented with 1% CLA (of total fat), a purified high fat (HF) diet (45%kcal from fat) and a purified HF diet supplemented with 1% CLA (of total fat) (HFCLA). All dams were fed ad libitum throughout pregnancy and lactation. Offspring were fed a standard chow diet from weaning (day 21) until the end of the study (day 150). Systolic blood pressure (SBP) was measured at day 85 and 130 by tail cuff plethysmography. At day 150, offspring mesenteric vessels were mounted on a pressure myograph and vascular responses to agonist-induced constriction and endothelium-dependent vasodilators were investigated. SBP was increased at day 85 and 130 in HF and HFCLA adult male offspring compared to CON and CLA groups with no effect of CLA supplementation. An overall effect of a maternal HF diet was observed in adult male vessels with a reduced vasoconstrictor response to phenylephrine and blunted vasodilatory response to acetylcholine (ACh). Furthermore, HF and HFCLA offspring displayed a reduction in nitric oxide pathway function and an increased compensatory EDHF function when compared to CON and CLA groups. These data suggest that a maternal HF diet causes a developmental programming of endothelial dysfunction and hypertension in male offspring which can be partially improved by maternal CLA supplementation, independent of offspring body weight.     

Insights into the genome of the enteric bacterium Escherichia blattae: cobalamin (B12) biosynthesis, B12-dependent reactions, and inactivation of the gene region encoding B12-dependent glycerol dehydratase by a new mu-like prophage

The enteric bacterium Escherichia blattae has been analyzed for the presence of cobalamin (B12) biosynthesis and B12-dependent pathways. Biochemical studies revealed that E. blattae synthesizes B12 de novo aerobically and anaerobically. Genes exhibiting high similarity to all genes of Salmonella enterica serovar Typhimurium, which are involved in the oxygen-independent route of B12 biosynthesis, were present in the genome of E. blattae DSM 4481. The dha regulon encodes the key enzymes for the anaerobic conversion of glycerol to 1,3-propanediol, including coenzyme B12-dependent glycerol dehydratase. E. blattae DSM 4481 lacked glycerol dehydratase activity and showed no anaerobic growth with glycerol, but the genome of E. blattae DSM 4481 contained a dha regulon. The E. blattaedha regulon is unusual, since it harbors genes for two types of dihydroxyacetone kinases. The major difference to dha regulons of other enteric bacteria is the inactivation of the dehydratase-encoding gene region by insertion of a 33,339-bp prophage (MuEb). Sequence analysis revealed that MuEb belongs to the Mu family of bacteriophages. The E. blattae strains ATCC 33429 and ATCC 33430 did not contain MuEb. Accordingly, both strains harbored an intact dehydratase-encoding gene region and fermented glycerol. The properties of the glycerol dehydratases and the correlating genes (dhaBCE) of both strains were similar to other B12-dependent glycerol and diol dehydratases, but both dehydratases exhibited the highest affinity for glycerol of all B12-dependent dehydratases characterized so far. In addition to the non-functional genes encoding B12-dependent glycerol dehydratase, the genome of E. blattae DSM 4481 contained the genes for only one other B12-dependent enzyme, the methylcobalamin-dependent methionine synthase.     

Structural Insights into the Dual Strategy of Recognition by Peptidoglycan Recognition Protein,PGRP-S: Structure of the Ternary Complex of PGRP-S with Lipopolysaccharide and Stearic Acid

Peptidoglycan recognition proteins (PGRPs) are part of the innate immune system. The 19 kDa Short PGRP (PGRP-S) is one of the four mammalian PGRPs. The concentration of PGRP-S in camel (CPGRP-S) has been shown to increase considerably during mastitis. The structure of CPGRP-S consists of four protein molecules designated as A, B, C and D forming stable intermolecular contacts, A–B and C–D. The A–B and C–D interfaces are located on the opposite sides of the same monomer leading to the the formation of a linear chain with alternating A–B and C–D contacts. Two ligand binding sites, one at C–D contact and another at A–B contact have been observed. CPGRP-S binds to the components of bacterial cell wall molecules such as lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN) from both Gram-positive and Gram-negative bacteria. It also binds to fatty acids including mycolic acid of the Mycobacterium tuberculosis (Mtb). Previous structural studies of binary complexes of CPGRP-S with LPS and stearic acid (SA) have shown that LPS binds to CPGRP-S at C–D contact (Site-1) while SA binds to it at the A–B contact (Site-2). The binding studies using surface plasmon resonance showed that LPS and SA bound to CPGRP-S in the presence of each other. The structure determination of the ternary complex showed that LPS and SA bound to CPGRP-S at Site-1 and Site-2 respectively. LPS formed 13 hydrogen bonds and 159 van der Waals contacts (distances ≤4.2 Å) while SA formed 56 van der Waals contacts. The ELISA test showed that increased levels of productions of pro-inflammatory cytokines TNF-α and IFN-γ due to LPS and SA decreased considerably upon the addition of CPGRP-S.     

Effects of Dietary Pantothenic Acid on Growth,Intestinal Function,Anti-Oxidative Status and Fatty Acids Synthesis of Juvenile Blunt Snout Bream Megalobrama amblycephala

Four groups of juvenile Megalobrama amblycephala were fed three times daily with six semi-purified diets containing 3.39 (PA unsupplied diet), 10.54, 19.28, 31.04, 48.38 and 59.72 mg kg^-1 calcium D-pantothenate. The results showed that survival rate, final weight, specific growth rate, protein efficiency ratio and nitrogen retention efficiency all increased significantly (P<0.01) as dietary PA levels increased from 3.39 to 19.28 mg kg^-1, whereas the opposite was true for feed conversion ratio. Whole-body crude protein increased as dietary PA levels increased, while the opposite pattern was found for the crude lipid content. Intestinal α-amylase, lipase, protease, Na⁺-K⁺-ATPase, alkaline phosphatase and gamma-glutamyl transferase activities were all elevated in fish fed PA-supplemented diets. Hepatic catalase activities improved with increases in dietary PA, while the opposite was true for malondialdehyde contents. The liver PA concentration and coenzyme A content rose significantly (P<0.01), up to 31.04 mg kg^-1, with increasing dietary PA levels and then plateaued. The percentage of hepatic saturated fatty acids increased significantly (P<0.01) as dietary PA levels increased, while the percentages of monounsaturated fatty acids and polyunsaturated fatty acid (PUFA) decreased as dietary PA increased. Fish fed diets containing 19.28 and 31.04 mg kg^-1 PA exhibited higher (P<0.01) docosahexaenoic acid and PUFA percentages in muscle than those fed with other diets. The expression of the gene encoding pantothenate kinase was significantly up-regulated (P<0.01) in fish fed PA-supplemented diets. Hepatic Acetyl-CoA carboxylase α, fatty acid synthetase, stearoyl regulatory element-binding protein 1 and X receptor α genes all increased significantly (P<0.01) as dietary PA levels increased from 3.39 to 31.04 mg kg^-1. Based on broken-line regression analyses of weight gain, liver CoA concentrations and PA contents against dietary PA levels, the optimal dietary PA requirements of juvenile blunt snout bream were estimated to be 24.08 mg kg^-1.