Effect of dietary lipid level on fatty acid beta-oxidation and lipid composition in various tissues of haddock,Melanogrammus aeglefinus L

Haddock (Melanogrammus aeglefinus) is a gadoid fish species that deposits dietary lipid mainly in the liver. The fatty acid (FA) beta-oxidation activity of various tissues was evaluated in juvenile haddock fed graded levels of lipid. The catabolism of a radiolabelled FA, [1-(14)C]palmitoyl-CoA, through peroxisomal and mitochondrial beta-oxidation was determined in the liver, red and white muscle of juvenile haddock fed 12, 18 and 24% lipid in the diet. There was no significant increase in the mitochondrial or peroxisomal beta-oxidation activity in the tissues tested as the dietary lipid level increased from 12 to 24%. Peroxisomes accounted for 100% of the beta-oxidation observed in the liver, whereas mitochondrial beta-oxidation dominated in the red (91%) and white muscle (97%) of juvenile haddock. Of the tissues tested, red muscle possessed the highest specific activity for beta-oxidation expressed on a per mg protein or per g wet weight basis. However, white muscle, which forms over 50% of the body mass in gadoid fish was the most important tissue in juvenile haddock for overall FA catabolism. The total lipid and FA composition of these tissues were also determined. This study confirmed that the liver was the major lipid storage organ in haddock. The hepatosomatic index (HSI; 10.0-15.2%) and lipid (73.8-79.3% wet wt.) in the liver increased significantly as dietary lipid was increased from 12 to 24% lipid. There was no significant increase in the lipid composition of the white muscle (0.8% wet wt.), red muscle (1.9% wet wt.) or heart (2.5% wet wt.).     

Determination of Trace Element Level in Different Tissues of the Leaping Mullet (Liza saliens, Mugilidae) Collected from Caspian Sea

The concentrations of Cr, Cu, Fe, Mn, Ni, Pb, Cd, and Zn were determined in the brain, heart, liver, gill, gonad, spleen, kidney, and red and white muscles of Liza saliens (leaping mullet). Trace element levels in fish samples were analyzed by flame atomic absorption spectrometry. Among the non-essential metals, the levels of Ni and Pb in the tissues were higher than limits for fish proposed by FAO/WHO, EU, and TFC. Generally, the levels of the non-essential metals were much higher than those of manganese in the red and white muscles. Fe distribution pattern in tissues was in order of spleen?>?liver?>?heart?>?gill?>?brain?>?kidney?>?gonad?>?red muscle?>?white muscle. Red muscle was not within the safe limits for human consumption because non-essential metal (Ni, Pb) contents were higher than standard limits.     

Intracellular ion content of skeletal muscle measured by instrumental neutron activation analysis

The intracellular contents of sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and chloride (Cl-) in rat hindlimb muscles (soleus, plantaris, white and red gastrocnemii) were measured by instrumental neutron activation analysis (INAA) and atomic absorption spectrophotometry (AAS). Muscle extracellular fluid volume (ECFV) was determined using [3H]mannitol, [14C]mannitol, [3H]polyethylene glycol (PEG, mol wt 900, PEG-900) or the chloride (Cl) method and intracellular fluid volume (ICFV) calculated. Rats were anesthetized with pentobarbital sodium. The muscles were biopsied, frozen in liquid nitrogen, freeze-dried, weighed, and transferred to vials for analysis. For a given muscle, ion contents measured by the two methods showed a consistent small difference which could not be explained. The PEG-900 space and the Cl method yielded a larger ECFV than did mannitol; it is concluded that PEG-900 and Cl overestimate ECFV. There were significant differences in total tissue water (TTW), ECFV, ICFV, and intracellular ion contents between the different muscle types. The fast glycolytic muscles (white gastrocnemius, plantaris) had lower TTW (758 ml/kg wet wt) and ECFV (6.5-8.5% TTW) but the highest ICFV; the soleus (slow oxidative fibers) had the highest TTW (766 ml/kg wet wt) and ECFV (10-15% TTW) but the lowest ICFV. The fast-twitch white gastrocnemius and plantaris muscles have a higher intracellular content of K+ and lower Na+ and Cl- than the slow-twitch soleus muscle. The technique of INAA provides a rapid and accurate means of determining intramuscular ion content in small samples of tissue.     

Cadmium and copper contents in a freshwater fish species (brook trout, Salvelinus fontinalis) from the subantarctic Kerguelen Islands

The subantarctic Kerguelen Islands (49°S, 70°E) contain freshwaters among the most isolated in the world from direct human activities. Cadmium and copper concentrations were analyzed in muscle and liver tissues of 57 non-migratory brook trout (Salvelinus fontinalis) inhabiting the Sud River of Kerguelen Islands. The mean cadmium concentration in liver was 1.13 μg/g dry wt, within the range of levels measured in liver of marine fish from the Southern Ocean. Muscular Cd levels (0.12 μg/g dry wt) were roughly ten times higher than those measured in Kerguelen’s marine fish species. Copper levels were very high in the two organs (62.27 μg/g dry wt in liver and 3.02 μg/g dry wt in muscle) compared to those detected in fish from the Southern Ocean. Regarding the seasonal trend, the highest Cu and Cd muscular levels were measured in fish at the end of the austral winter, whereas the highest hepatic levels were observed at the end of the austral summer. Moreover, hepatic cadmium levels were higher in females than in males. These results could be related to brook trout spawning physiological preparations and foraging behavior during the summer period. We provide here the first results about Cu and Cd levels in liver and muscle of a freshwater fish species in an insular subantarctic context. They are in agreement with the high cadmium contamination found in fish of the Southern Ocean.     

MICROASSAY OF ADENOSINE-3′,5′-MONOPHOSPHATE (CYCLIC AMP) IN BRAIN AND OTHER TISSUES BY THE LUCIFERIN-LUCIFERASE SYSTEM1

Abstract— A simple, sensitive and specific method for assaying cyclic AMP in various tissues is reported. Cyclic AMP was isolated from contaminating nucleotides and was converted to ATP with a phosphodiesterase-myokinase-pyruvate kinase system. The ATP was determined enzymically in a liquid scintillation counter by the firefly luciferin-luciferase technique. This procedure was capable of detecting as little as 5 × 10^?14 mol of cyclic AMP and could therefore be used for analyses on less than 1 mg of brain. The assay was reproducible and linear over a wide range of tissue concentrations. In the rat, the highest levels of cyclic AMP (2.7–4.2 pmol/mg wet wt. of tissue) were present in the pineal, heart, pituitary, thyroid, cerebellar cortex, kidney, adrenal, liver and pyloric region of the stomach; intermediate levels (1.5–2.7 pmol/mg wet wt. of tissue) were found in testis, skin, aorta, intestine, submaxillary gland, spleen, muscle and cerebral cortex, moderately low levels (1.0–1.5 pmol/mg wet wt. of tissue) were found in lung, trachea and greater curvature of the stomach; whereas low levels (0.15–0.60 pmol/mg wet wt. of tissue) were found in adipose tissue.     

Heavy Metals in Antarctic Notothenioid Fish from South Bay, Livingston Island, South Shetlands (Antarctica)

The Pb, Cd, Cu, Zn, and Mn contents of the liver, spleen, muscle, bones, scales, gills, and the whole body of 3- to 7-year-old notothenioid Antarctic cod (Notothenia coriiceps, Richardson, 1844) were measured. The highest heavy metal concentrations obtained are as follows: Cd in liver, the mean value was 1.36 ± 0.19 mg/kg dry weight (wt); Pb and Zn in spleen, the mean values were 3.33 ± 0.86 and 143.97 ± 16.17 mg/kg dry wt, respectively; Cu in gills, 3.76 ± 1.16 mg/kg dry wt; and Mn in scales, 14.80 ± 4.77 mg/kg dry wt. The comparison with the data reported up to now shows that the metal concentrations varied within relative wide ranges. These first data obtained could be used as a baseline to investigate further relationships among metal contents in fish, their diet, and habitat.     

Effects of mevinolin treatment on tissue dolichol and ubiquinone levels in the rat.

Rats were treated with mevinolin by intraperitoneal injection (15 days) or dietary administration (30 days). The cholesterol, dolichol, dolichyl phosphate and ubiquinone contents of the liver, brain, heart, muscle and blood were then investigated. The cholesterol contents of these organs did not change significantly, with the exception of muscle. Intraperitoneal administration of the drug increases the amount of dolichol in liver, muscle and blood and decreases the dolichyl-P amount in muscle. The same treatment increases the level of ubiquinone in muscle and blood and decreases this value in liver and heart. Oral administration decreases dolichol, dolichyl-P and ubiquinone levels in heart and muscle, while in liver the dolichol level is elevated and ubiquinone level lowered. In brain the amount of dolichyl-P is increased. Intraperitoneal injection of mevinolin also modifies the liver dolichol and dolichyl-P isoprenoid pattern, with an increase in shorter chain polyisoprenes. The levels of dolichol and ubiquinone in the blood do not follow the changes observed in other tissues. Incorporation of [3H]acetate into cholesterol by liver slices prepared from mevinolin-treated rats exhibited an increase, whereas in brain no change was seen. Labeling of dolichol and ubiquinone was increased in both liver and brain, but incorporation into dolichyl phosphate remained relatively stable. The results indicate that mevinolin affects not only HMG-CoA reductase but, to some extent, also affects certain of the peripheral enzymes, resulting in considerable effects on the various mevalonate pathway lipids.     

Effect of cadmium intoxication on glucose utilization in energy metabolism of muscles

The influence of cadmium intoxication on carbohydrate metabolism in skeletal muscles and liver of the male Wistar rats has been studied. Cadmium was administered as cadmium acetate in a dose of 0.3 mg Cd2+/kg body weight for three months. At the same time the control rats were injected with 0.9% NaCl. The animals were decapitated and samples of their skeletal muscles: the soleus muscle (composed mainly of red slow twitch fibers; ST) the gastrocnemius muscle containing two types of fibers (white fast twitch fibers FTb and red fast twitch fibers, FTa) and the liver were dissected out. In the samples of muscles, liver and serum contents of glycogen, glucose, pyruvate and lactate, as well as activities of hexokinase, pyruvate kinase and lactate dehydrogenase were measured. Intoxication of rats with cadmium for three months resulted in a reduction of glycolytic enzymes in the serum, ST and FTa muscle fibers and in the liver but did not change the activities of glycolytic enzymes in the FTb muscle fibers. The data obtained for the concentrations of glycogen in the liver and skeletal muscles suggest different mechanisms of cadmium influence on glycogen utilization in these organs.     

Influence of breed on blood and tissue copper status in growing and finishing steers fed diets supplemented with copper

To evaluate the influence of breed on the accumulation of dietary copper (Cu) in tissue, and on blood parameters indicative of Cu status, ten Galician Blond, nine Holstein-Friesian and ten Galician Blond × Holstein-Friesian cross (GB × HF) steers were fed diets supplemented with 35 mg/kg DM of CuSO₄ during their growing and finishing periods. Blood samples were taken monthly, and samples of liver, kidney, brain, heart, spleen and muscle were taken at slaughter. Cu concentrations were determined by ICP-AES. Holstein-Friesian calves had significantly higher total liver Cu contents than Galician Blonds and GB × HF crosses (mean 1070, 663 and 868 mg, respectively), combined with higher hepatic Cu concentrations (174, 140 and 166 mg/kg wet weight, respectively). Holstein-Friesian calves had also the highest prevalence (89%) of hepatic Cu concentrations exceeding the toxic limit of 150 mg/kg wet weight. Breed did not have a statistically significant influence on blood parameters. With the exception of the semitendinosus muscle, where Holstein-Friesians (0.790 mg/kg) had significantly higher Cu levels than Galician Blonds (0.541 mg/kg) or GB × HF crosses (0.631 mg/kg), no other statistically significant differences by breed in the extrahepatic tissue Cu distribution were observed. A negative statistical association between carcass performance and the ratio of semitendinosus and liver Cu concentration could indicate that the animals with a better carcass performance (Galician Blonds) could need a higher Cu mobilisation into the muscle, resulting in a lower hepatic storage.     

Mercury in wild terrestrial carnivorous mammals from north-western Poland and unusual fish diet of red fox

Total mercury concentrations were determined in the kidney (K), liver (L), and pectoral muscle (M) of 19 individuals representing wild carnivorous mammals from NW Poland: 10 red foxes Vulpes vulpes (Linnaeus, 1758), 3 raccoon dogs Nyctereutes procyonoides Gray, 1834, 2 badgers Meles meles Linnaeus, 1758, 3 pine martens Martes martes Linnaeus, 1758, and 1 polecat Mustela putorius Linnaeus, 1758. The sample of red fox included 3 immature specimens found on Mielin Island; the island supports a black cormorant colony, and the foxes found there had fed mostly on cormorant nestlings as well as on fish and their remains. In addition to the Mielin Island foxes, the group of foxes included 3 other immature and 4 adult individuals. The highest mean of mercury concentrations were revealed in the Mielin red fox juveniles: 5.11, 4.52, and 1.56 mg/kg d.w. being recorded in K, L, and M. No significant differences in mercury concentrations in the respective tissues were found between the remaining immature and adult red foxes; their mercury concentrations were several times lower than those of the Mielin individuals. In all the animals except the Mielin foxes, mercury concentrations in K, L, and M did not exceed 1.3, 1.0 and 0.5 mg/kg d.w., respectively, the highest values being in badgers (which feed mostly on soil invertebrates), followed by pine martens and then the canids (red fox and raccoon dog). Studies on common and widely distributed terrestrial animals, particularly red fox and badger, may provide numerous valuable comparative data on mercury contamination of different areas of the northern hemisphere.     

Quantitation of myosin in muscle

The amount of myosin per gram of cardiac and skeletal muscle was determined in sodium dodecyl sulfate-solubilized tissue homogenates by radioimmunoassay and by isotope dilution. In the rabbit ventricle, there was an average of 27 mg myosin/g wet wt of tissue. In chickens, the myosin content of typical "red" (anterior latissimus dorsi) and "white" (posterior latissimus dorsi) skeletal muscles was higher than that of ventricular muscle, averaging 36 and 48 mg/g of tissue, respectively. The stoichiometry of the heavy and light chains in cardiac myosin was also determined from the quantitative binding of 125I-labeled Coomassie blue to each subunit after separation of the subunits by sodium dodecyl sulfate-gel electrophoresis. With this procedure, we found that the combined light-chain subunits contributed 19% of the myosin mass. After adjustment for the light-chain contribution, the myosin heavy-chain content of the rabbit ventricle averaged 22 mg/g wet wt of tissue.     

Effects of etretinate on the distribution of elements in rats

We studied in the rat the effects of the drug etretinate (Tigason), given at three doses 3, 10, and 30 mg/kg body wt for 1 mo, on the concentrations of Na, K, Ca, Mg, Fe, S, P, Cu, and Zn in the plasma, brain, thymus, heart, liver, lung, kidney, testicle, muscle, and bone. The elements were simultaneously determined in tissues after nitric acid dissolution by inductively coupled plasma emission spectrometry using a JY 48 instrument. At the dose of 3 mg/kg, etretinate did not induce any statistically significant modifications of the element distribution. At the dose of 10 mg/kg, the main observed modifications were in plasma an increase of copper (+38%) and a decrease of zinc (-25%). At the highest dose of 30 mg/kg, some variations of the concentrations of elements in tissues were observed. But, on no account did retinoids induce an alteration of the mineral composition of bone, despite obvious macroscopic bone alterations.     

养殖史氏鲟不同部位氨基酸组成

测定了史氏鲟不同部位中17种氨基酸的含量,并对它们的营养价值进行了评价,结果表明,虽然史氏鲟各部位中常见氨基酸种类较为齐全,但不同部位中氨基酸总量和组成差异极其显著,氨基酸总量范围在3.26~105.0 mg.g-1,平均氨基酸含量52.2±36.9 mg.g-1。人体必需氨基酸含量略低于其他主要经济鱼类,但呈味氨基酸百分比介于鲷科鱼类和石首科鱼类之间。除了肌肉外,心脏、食道和鳔等部位中必需氨基酸和营养等级较高,具有综合利用价值。     

Fluoride,Some Selected Elements,Lipids, and Protein in the Muscle and Liver Tissues of Five Fish Species along the Egyptian Mediterranean Sea Coast

Fish is a vital, healthy source of animal protein and vitamins. This study was oriented to estimate fluoride, some selected elements, lipids, and protein concentrations in fish. Five fish species were collected from the Egyptian Mediterranean Sea coast during April 2007. Variable content of fluoride, calcium, magnesium, sulphate, phosphorus, lipids, and protein were determined in muscle and liver of fish samples and yielded average values in fish muscle of 11.0 ± 2.0 μg/g, 6.5 ± 3.8 mg/g, 100.2 ± 39.3 mg/g, 4.4 ± 6.3 mg/g, 2.4 ± 0.5 mg/g, 6.0 ± 2.2 mg/l, and 2.6 ± 1.0 g% wet wt, respectively. Special attention was given to fluoride because of its hazardous classification. Interestingly, the hazard index values of fluoride were less than 1 for all collected fish species. Additionally, the daily fluoride exposure was generally below the nutrient reference values for Australian and New Zealand populations. Accordingly, there is little human health risk from the selected fish species due to consumption of fluoride-contaminated fish.     

Quantitation of ryanodine receptor of rabbit skeletal muscle, heart and brain

The total number of high-affinity ryanodine receptor (RyR) binding sites present in skeletal and cardiac muscle and in brain tissue of the rabbit was determined by [3H]ryanodine binding to subfractions obtained by differential centrifugation of homogenates prepared in a low-ionic strength medium, containing 0.5% Chaps. In all three tissues at least 80% of [3H]ryanodine binding was recovered in the total membrane (TM) fraction obtained by centrifuging between 650 g for 10 min and 120,000 x g for 90 min. Skeletal muscle displayed higher contents of high-affinity RyR sites (about 49 pmol/g wet wt) than heart and brain (about 12 pmol and 3.5 pmol/g wet wt, respectively). The affinity for ryanodine, as well as the affinity for Ca2+, in the absence or presence of Ca2(+)-releasing drugs (caffeine and doxorubicin) of TM from skeletal muscle, were found to be identical to those of purified terminal cisternae. As low as 1 g of tissue was sufficient to perform several experiments.     

Bioaccumulation of heavy metals in tissues of selected fish species from Ganga river,India, and risk assessment for human health

The study measured the concentration of Cd, Cr, Pb, Cu, and Zn in various fish tissues (muscle, gills, and liver) of 18 fish species (C. gachua, C. marulius, C. punctatus, C. nama, C. ranga, H. fossilis, C. batrachus, P. ticto, P. phutunio, L. rohita, L. calbasu, L. gonius, T. putitora, T. tor, R. rita, G. chapra, H. ilisa, and N. botia) collected from Ganga river. It is the survey regarding metal concentration in fish tissues increasing day by day. The metal concentration in different fish tissues varied on the following range: Cu (0.45–8.54 µg/g wet wt), Zn (0.07–2.2 µg/g wet wt), Pb (0.20–2.62 µg/g wet wt), Cd (0.07–2.32 µg/g wet wt), and Cr (0.09–1.74 µg/g wet wt). The results show the concentration of Pb, Cd, and Cr metals to be higher than internationally recommended standard limits (as determined by the WHO and FAO) and other similar studies. Generally, higher concentrations of metals were found in liver and gills than muscles. Despite lower estimated daily intake (EDI) of fish in the area (per recommended daily allowance guidelines), values of daily average consumption were lower than the recommended values by FAO/WHO/EFSA, and in fish samples these were below the provisional permissible levels for human consumption. The continuous exposure to heavy metals has been linked to the development of mental retardation, kidney damage, various cancers, and even death in instances of very high exposure in human body.     

Activation of AMP-activated protein kinase increases mitochondrial enzymes in skeletal muscle.

Muscle contraction causes an increase in activity of 5'-AMP-activated protein kinase (AMPK). This study was designed to determine whether chronic chemical activation of AMPK will increase mitochondrial enzymes, GLUT-4, and hexokinase in different types of skeletal muscle of resting rats. In acute studies, rats were subcutaneously injected with either 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR; 1 mg/g body wt) in 0.9% NaCl or with 0.9% NaCl alone and were then anesthetized for collection and freezing of tissues. AMPK activity increased in the superficial, white region of the quadriceps and in soleus muscles but not in the deep, red region of the quadriceps muscle. Acetyl-CoA carboxylase (ACC) activity, a target for AMPK, decreased in all three muscle types in response to AICAR injection but was lowest in the white quadriceps. In rats given daily, 1 mg/g body wt, subcutaneous injections of AICAR for 4 wk, activities of citrate synthase, succinate dehydrogenase, and malate dehydrogenase were increased in white quadriceps and soleus but not in red quadriceps. Cytochrome c and delta-aminolevulinic acid synthase levels were increased in white, but not red, quadriceps. Carnitine palmitoyl-transferase and hydroxy-acyl-CoA dehydrogenase were not significantly increased. Hexokinase was markedly increased in all three muscles, and GLUT-4 was increased in red and white quadriceps. These results suggest that chronic AMPK activation may mediate the effects of muscle contraction on some, but not all, biochemical adaptations of muscle to endurance exercise training.     

Effect of cocaine on exercise endurance and glycogen use in rats

To determine the effects of cocaine on exercise endurance, male rats were injected intraperitoneally with cocaine (20 mg/kg body wt) or saline and then run to exhaustion 20 min later at 22 m/min and 15% grade. Saline-injected animals ran 74.9 +/- 16.5 (SD) min, whereas cocaine-treated rats ran only 29 +/- 11.6 min. The drug had no effect on resting blood glucose or lactate levels, nor did it affect resting glycogen levels in liver or red and white vastus muscle. However, it did reduce resting soleus glycogen content by 30%. During exercise liver and soleus glycogen depletion occurred at the same rate in saline- and cocaine-treated animals. In contrast, the rate of glycogen depletion during exercise in red and white vastus was markedly increased in cocaine-treated rats with a corresponding elevation in blood lactate (12 vs. only 5 mM in saline group) at exhaustion. These data suggest that cocaine administration (20 mg/kg) before submaximal exercise dramatically alters glycogen metabolism during exercise, and this effect has a negative impact on exercise endurance.     

Strategies for maintaining Na⁺ balance in zebrafish (Danio rerio) during prolonged exposure to acidic water

Teleost fish store lipids among several tissues primarily as triacylglycerol (TG). Upon metabolic demand, stored TGs are hydrolyzed by hormone-sensitive lipase (HSL). In this study, two distinct cDNAs encoding HSL were isolated, cloned, and sequenced from adipose tissue of rainbow trout. The full-length cDNAs, designated HSL1 and HSL2, were 2562-bp and 2887-bp in length, respectively, and share 82% nucleotide identity. Phylogentic analysis suggests that the two HSLs derive from paralogous genes that may have arisen during a teleost-specific genome duplication event. Quantitative real-time PCR revealed that HSL1 and HSL2 were differentially expressed, both in terms of distribution among tissues as well as in terms of abundance within selected tissues of juvenile trout. HSL1 and HSL2 mRNAs were detected in the brain, spleen, pancreas, kidney, gill, intestine, heart, and white muscle, but were most abundant in the red muscle, liver, and adipose tissue. HSL1 mRNA was more abundant than HSL2 mRNA in the adipose tissue, whereas HSL2 mRNA was more abundant than HSL1 mRNA in the liver. Short term fasting (4 weeks) increased HSL1 and HSL2 mRNA expression in the adipose tissue, but only HSL1 mRNA levels increased in the liver and the red muscle. During a prolonged fast (6 weeks), there was continued elevation of HSL1 and HSL2 mRNA levels in the liver and muscle; HSL mRNA expression in mesenteric fat declined, coincident with depletion of mesenteric fat mass. Refeeding fish reduced HSL expression to levels seen in continuously fed fish. These findings indicate that the pattern of HSL expression is consistent with the diverse lipid storage pattern of fish and suggest that distinct mechanisms serve to regulate differential expression of the two HSLs in tissues and during a progressive fast.     

The effect of dietary vitamin B6 on tissue fat contents and lipid composition in livers and gills of Atlantic salmon (Salmo salar)

Atlantic salmon (9 g) were fed a basal experimental diet supplemented with vitamin B₆ at 0, 5 and 10 mg/kg for 10 weeks. Vitamin b₆ unsupplemented fish showed reduced lipid contents in muscle, and reduced levels of 22:6n-3 and sum n-3 fatty acids in the hepatic phospholipids PE and PS. In gills, the fatty acid pattern was not influenced by the dietary vitamin B₆ contents. Desaturation and elongation of [1-¹⁴C]18:3n-3 in liver following intraperitoneal injection was not affected by dietary vitamin b₆. Liver weights, the hepatosomatic index and the activity of aspartate aminotransferase and concentration of vitamin B₆ in white muscle increased with increasing dietary vitamin B₆ levels, and were significantly highest in the highest supplemented fish.