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K Dabrowski

Publications and source records attributed to K Dabrowski.

At least 19 recordsLinked to original sources
PubMed1996

Ascorbic acid protects against male infertility in a teleost fish.

An animal unable to synthesize ascorbic acid uniquely mimicks human and non-human primates. Therefore, in this study we used the rainbow trout, a teleost fish, as the model animal to study the importance of dietary ascorbic acid on the fertilizing ability of sperm. A high concentration of ascorbic acid in semen plays a key role in maintaining the genetic integrity of sperm cells, by preventing oxidative damage to sperm DNA. This study will show that the concentration of ascorbic acid in seminal plasma reflects the dietary intake of vitamin C. The concentration of ascorbic acid in seminal plasma of fish declined significantly in groups fed either an ascorbate-free diet (from 4.74 +/- 0.9 to 0.16 +/- 0.08 microgram ml-1) or an ascorbate-rich diet (from 37.9 +/- 4.7 to 17.7 +/- 3.2 microgram ml-1) during the spermiation season. The relationship between ascorbate status and fertility was studied in six groups of fish fed graded levels of ascorbic acid, which spermiated over a 150-day-period. Sperm from individual males was used to fertilize several batches of eggs. When the seminal plasma ascorbate concentration decreased to 7.3 microgram ml-1 a significant decrease of fertilization rate and the hatching rate of embryos resulted. This is the first evidence that dietary ascorbate level directly affected sperm quality and influenced male fertility in a scurvy-prone vertebrate.

Animals↗
PubMed1996

Utilization of the bone/liver alkaline phosphatase activity ratio in blood plasma as an indicator of ascorbate deficiency in salmonid fish.

The goal of this study was to test the hypothesis that the ratio of liver to bone alkaline phosphatase in blood plasma reflects the ascorbate status in scurvy-prone teleost fish (rainbow trout [Oncorhynchus mykiss]). The studies focused on finding a method for distinguishing bone alkaline phosphatase present in blood plasma from other alkaline phosphatase isoforms. We tested temperature optima and thermostability of liver, kidney, gill cartilage, and intestinal alkaline phosphatases. We did not observe differences among liver, bone, and kidney enzymes with respect to temperature optima and thermostability. We partially purified alkaline phosphatase from juvenile rainbow trout vertebrae and liver using n-butanol solubilization and ammonium sulfate fractionation. We found a difference between bone alkaline phosphatase, which precipitated in 0%-20% ammonium sulfate saturation, and liver enzyme, which required 40%-50% ammonium sulfate saturation to precipitation. We conducted a series of urea inactivation studies on partially purified enzymes from liver and vertebrae. Urea differentially inhibited the enzymes with t 1/2 = 1.1 and 0.4 min, for bone and liver, respectively. Subsequently, we subjected blood plasma alkaline phosphatase to urea inhibition, and using regression analysis we calculated the ratio of liver to bone alkaline phosphatase. We found that thus obtained ratios of bone enzyme in blood plasma correlated with liver ascorbate concentration. Bone alkaline phosphatase declined in ascorbate deficiency 10-fold, whereas low ascorbate status resulted in a 3.5-fold decrease. In order to draw a general conclusion on the linearity of the response of blood plasma/bone alkaline phosphatase as an indicator of ascorbate deficiency in fish, further studies must include analysis of individual fish followed in the process of developing avitaminosis.

Alkaline Phosphatase↗
PubMed1995

Protective effect of seminal plasma proteins on the degradation of ascorbic acid.

The objectives of this study were to determine ascorbic acid stability and its effect on antiproteinase activity of seminal plasma in the presence of an oxidant. Effect of seminal plasma, and additives: glutathione, albumin, hydrogen peroxide and Tris buffer, on ascorbic acid degradation was investigated by UV absorbance. Antiproteinase against trypsin amidase activity was measured spectrophotometrically using N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) as substrate. Ascorbic acid was destroyed much more rapidly with the addition of hydrogen peroxide than in Tris buffer at pH 8.2 alone. Seminal plasma protected ascorbic acid more efficiently than glutathione and albumin alone. The protective effect of seminal plasma on ascorbic acid degradation may closely relate to the function of ascorbic acid in reproductive system of scurvy-prone animals including teleost fish. Within the range of 1-8 mM concentrations, ascorbic acid had a pro-oxidant action on seminal plasma antiproteinase activity in vitro when they were incubated with hydrogen peroxide.

Animals↗
PubMed1995

Ascorbate polyphosphate is a bioavailable vitamin C source in juvenile rainbow trout: tissue saturation and compartmentalization model.

We studied the bioavailability of ascorbic acid ester, ascorbate polyphosphate, to juvenile rainbow trout (Oncorhynchus mykiss). Fish were fed molar equivalents of 0, 20, 40, 80, 160, 320 and 1280 mg ascorbic acid/kg diet in the form of ascorbate polyphosphate. During the 18 wk of the experiment, when body weight increase averaged 3.5-fold, we did not observe any deficiency symptoms in any group. Liver and kidney ascorbate concentrations differed significantly among groups after wk 9. The ascorbic acid concentrations in liver were significantly different in fish fed for 9 wk an equivalent of 0, 40 and 160 mg ascorbic acid/kg as ascorbate polyphosphate, values were 22.7 +/- 3.4, 93.7 +/- 17.0 and 368.0 +/- 60.8 nmol ascorbic acid/g. The ascorbic acid concentrations in kidney were significantly different in fish fed for 18 wk an equivalent of 0,20 and 40 mg ascorbic acid/kg as ascorbic polyphosphate (23.9 +/- 4.0, 72.1 +/- 13.6 and 254.4 +/- 22.7 nmol ascorbic acid/g, respectively). After wk 18, fish from groups fed 0, 20, 320 and 1280 mg ascorbic polyphosphate/kg were intraperitoneally injected with 25 mg/ascorbic acid/kg body wt. We observed differences in the profiles of tissue ascorbate concentration during the 96 h following the injection between groups with high and low tissue ascorbate concentration, i.e., fish fed 320 and 0 ascorbic acid/kg, respectively. We conclude that ascorbic acid metabolism in rainbow trout after intraperitoneal injection followed the three-compartmental model, with the intraperitoneal cavity as the first compartment, blood as the second, and tissues as the third.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Reproductive success of female rainbow trout (Oncorhynchus mykiss) in response to graded dietary ascorbyl monophosphate levels.

Ascorbic acid is an essential nutrient in rainbow trout diets and has been shown to play an important role in fish reproduction. Recommended dietary levels are based on immature fish, and the specific requirements for brood stock are unknown. To establish the optimum dietary level for mature rainbow trout, six graded levels of ascorbyl-2-monophosphate were fed to groups of female fish over a period of 10 mo until spawning. Increasing dietary levels of ascorbyl monophosphate resulted in significantly increased ascorbic acid concentrations in liver, kidney, ovaries, and ovulated eggs. Liver and egg concentrations were saturable at 109.3 and 266.6 micrograms ascorbic acid/g tissue, respectively. Tissue saturation levels of 83.7% and 91.2%, respectively, were reached at the highest dietary level (870 mg ascorbyl monophosphate/kg diet) tested. Both fecundity and embryo survival increased significantly with dietary ascorbyl monophosphate levels. The results indicated that the present National Research Council recommended dietary level of 50 mg ascorbic acid/kg diet for rainbow trout is inadequate for brood stock fish. An amount 8 times higher is necessary to optimize tissue ascorbic acid levels and achieve maximum reproductive success.

Animals↗
PubMed1995

Sperm quality and ascorbic acid concentration in rainbow trout semen are affected by dietary vitamin C: an across-season study.

High concentrations of ascorbic acid occur in scurvy-prone, teleost fish plasma. We quantified seasonal relationships between 1) dietary level of vitamin C and level of seminal plasma ascorbic acid, and 2) seminal plasma ascorbic acid concentration and sperm quality, in rainbow trout (Oncorhynchus mykiss). We maintained six groups of 2-yr-old rainbow trout on diets supplemented with 0, 30, 110, 220, 440, and 870 ppm ascorbyl monophosphate beginning in May 1992. Sperm were produced during the end of October 1992 through April 1993; we collected milt 13 times from 3-8 fish per treatment. We quantified ascorbic acid concentration in seminal plasma, and sperm concentration, motility, and weight. Seminal plasma ascorbic acid concentrations were affected directly by the ascorbyl monophosphate level in the diet. Seminal plasma ascorbic acid concentrations also were affected by season. Ascorbic acid deficiency did not influence semen quality (sperm concentration and motility) at the beginning of the spawning season. However, sperm concentration and motility in a group fed an ascorbic acid-free diet declined during the period of study. Ascorbic acid deficiency reduced both sperm concentration and motility, and thus fertility, of rainbow trout. These results indicate that vitamin C is important for male fish reproduction; the dietary requirement for seminal plasma ascorbic acid saturation exceeds that for optimum growth.

Animals↗
PubMed1994

Efficacy of magnesium-L-ascorbyl-2-phosphate as a vitamin C source for weanling and growing-finishing swine.

Two experiments were conducted, one with weanling pigs (n = 288) and the second with grower-finisher swine (n = 216), to evaluate the efficacy of dietary vitamin C on various performance and serum measurements. Magnesium-L-ascorbyl-2-phosphate (46% L-ascorbic acid) served as the vitamin C source and was incorporated at dietary levels of 0, 50, or 500 ppm in both experiments. Pigs were allotted by sex, weight, and litter to randomized complete block designs. The nursery trial was conducted at four time periods and contained 12 replicates, whereas the grower-finisher experiment was over four time periods and contained nine replicates. Blood samples were collected initially from nine randomly selected pigs in both experiments, and from each pig within each pen at 2 and 5 wk postweaning, and at the 4- and 8-wk period in the grower-finisher trial. A killed Salmonella typhinurium bacterin was injected i.m. into starter pigs at 2 wk postweaning and at wk 4 and 6 in grower-finisher pigs. Hemagglutination titers were evaluated at 5 wk with the nursery pigs and at the 8-wk period with the grower-finisher swine. At the end of the grower-finisher trial, liver and kidney tissue were analyzed for ascorbate. Starter pigs grew faster (P < .05) and had improved gain:feed ratios (P < .05) when vitamin C was provided during the first 2 wk postweaning, but not during the latter 3-wk period. There was no improvement in pig gain or feed efficiency to vitamin C supplementation during any phase of the grower-finisher period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Ascorbate-2-sulfate sulfohydrolase in fish and mammal. Comparative characterization and possible involvement in ascorbate metabolism.

1. The new assay conditions were determined for crude and purified enzyme ascorbate-2-sulfate sulfohydrolase from liver tissues of two fish species and bovine. 2. The major departure from the existing indirect method, based on reduction of 2,6-dichlorophenolindophenol (DCIP) by released ascorbic acid and change from pink-blue to a colorless molecule, takes into account the shift of maximum absorbance of DCIP from 516 nm at pH 5.14 to 600 nm at pH 6.5. 3. The direct method is based on colorimetric assay of liberated ascorbic acid including correction for interfering substances. The optimum pH for both fish ascorbate sulfatases was 5.5. 4. The Km for bovine ascorbate sulfatase was confirmed to be approximately 7 mM at 37 degrees C. 5. Partly purified ascorbate-sulfate sulfohydrolase has a Km value in rainbow trout of 0.4 mM and it changes very little in the range of water temperatures characteristic for this stenothermic fish species. 6. In eurythermic chub, the Km values increased from 1.2 to 4.3 mM with rising temperatures.

2,6-Dichloroindophenol↗
PubMed1991

The effect of large doses of vitamin C and magnesium on stress responses in common carp, Cyprinus carpio.

1. Plasma magnesium, cortisol, lactate and ascorbic acid were examined in common carp subjected to various dietary treatments and following handling stress. 2. Under conditions of satisfied dietary magnesium and ascorbate requirements, plasma cortisol concentration after stress increased less pronouncedly than in fish fed large doses of ascorbate and/or magnesium. 3. Plasma lactate increased significantly in all groups after stress, although the increase seemed to be more severe (detrimental) in fish on large doses of ascorbate, either as ascorbic acid (AA) or ascorbic monophosphate Mg salt (AP). 4. Large doses of dietary ascorbate, both AA and AP, resulted in a significant increase of total ascorbate concentration in kidney and hepatopancreas of carp in comparison to pre-experimental level. 5. Kidney total ascorbate concentration decreased by 10-23% in all groups but one in which fish fed diet supplemented with AA displayed a significant increase (30%) of tissue ascorbate. The opposite trend was found in hepatopancreas of AA group with 21.5% ascorbate depletion. 6. The present results suggest that plasma cortisol and kidney (steroidogenesis site) and hepatopancreas ascorbate concentration responses to stress may not be related. Our results also do not support the hypothesis of the primary role of the high concentration of ascorbate in the kidney inhibiting steroidogenesis.

Animals↗
PubMed1990

Absorption of ascorbic acid and ascorbic sulfate and ascorbate metabolism in common carp (Cyprinus carpio L.).

Ascorbate metabolism was analyzed in fasted common carp and carp offered diets lacking ascorbic acid or supplemented with ascorbic acid (AA) or ascorbic sulfate (AS). Ascorbic acid and ascorbic sulfate were analyzed in the contents collected from various parts of the digestive tract. The major site of the dietary ascorbate absorption was located in the first 20% of the anterior intestine region (58.7 +/- 10.2%), whereas absorption increased to 94.3 +/- 1.9% (in the whole gut). Considerable secretion of ascorbate into the initial part of the intestine was found (71 micrograms AA.g-1 dry food) in fish offered the diet lacking ascorbate, but this amount was completely reabsorbed in the following portions of the intestine. AS was concentrated in the contents of the digestive tract and the external marker method revealed no absorption of AS from the intestine. In fish fed the AA-supplemented diet, the concentration of ascorbate in plasma, hepatopancreas, kidney, intestine, spleen, and brain was significantly (P less than 0.01) higher than in similar tissues from the other groups, suggesting that ascorbic sulfate hydrolysis was ineffective. Small amounts of AS were found in the intestine and spleen of fish fed a diet supplemented with AS. Ascorbate analysis in the whole fish allowed the estimate of the catabolic rate of fasting and scorbutic-diet-fed fish, which amounted to 0.7% and 1.46% daily of the ascorbate body pool, respectively. There was no indication that ascorbic sulfate sulfohydrolase activity was induced in hepatic, kidney, or intestinal tissue of fish offered a diet with AS in comparison to other groups. It seems unlikely that cyprinid fish are able to utilize ascorbic sulfate as a vitamin C source, and thus resemble scurvy-prone mammals in this respect.

Animals↗
PubMed1990

Effect of species differences and dietary vitamin C on the concentration of ascorbate- and acid-soluble thiol in fish eye.

Data presented confirm the essentiality of modification of the dinitrophenylhydrazine (DNPH) method to analyze the total ascorbic acid and dehydroascorbic acid in ocular tissues and stress the need of corrections for the interfering substances. Variations in ascorbate and thiol concentrations in the lens, retina and aqueous humour of freshwater fish belonging to the Cyprinidae family were examined. The interspecific variability of ascorbate concentration was highest in the aqueous humour and lowest in the retina. The high ascorbate concentration in the retina seems to reflect the importance of the sense of vision in fish life-style as compared to chemo- and acoustico lateralis senses. The regional distribution of the total ascorbate is in the order of decreasing concentrations: retina, lens and aqueous humour. However, the retinal ascorbate is almost exclusively in the oxidized form, and the lenticular ascorbate is almost exclusively in the reduced form. Thiol concentration in the lens is five- to tenfold that in the retina and aqueous humour. This explains the oxidation status of ascorbate in different eye compartments of the eye. After 30 days on diets containing various levels of ascorbic acid or ascorbic acid sulphate, the ascorbate concentration in the eye compartments of common carp (Cyprinus carpio L.) was determined. Ocular tissue can be used to monitor the development of the ascorbate status in fish, and the retina is the most responsive tissue to the enhanced or depleted ascorbate levels.

Animals↗
PubMed1990

Gulonolactone oxidase is missing in teleost fish. The direct spectrophotometric assay.

Data in the literature imply that some fish species evolved with the capacity to synthesize ascorbic acid. Gulonolactone oxidase activity has been reported in kidney and/or liver tissues. However, it is shown here that this microsomal enzyme activity is missing in common carp hepatopancreas and kidney, whereas high activity was confirmed in pigeon kidney, rat liver, bovine liver and amphibian (Xenopus) kidney tissues. A new assay using either the whole tissue homogenate or microsomes solubilized by sodium deoxycholate was developed to directly measure the formation of ascorbic acid spectrophotometrically. Identical values were found using this assay as well as the assay in which formed ascorbate was determined by the dinitrophenyl hydrazine (DNPH) method. In some experiments, these results were confirmed by polarographically measured oxygen consumption.

Animals↗
PubMed1990

Influence of dietary magnesium on mineral, ascorbic acid and glutathione concentrations in tissues of a freshwater fish, the common carp.

Supplementation with dietary Mg at a minimum level of 0.06% seems to be essential to prevent the hypercalcinosis of the kidney and hepatopancreas in a fish, the common carp. Mg deficiency appears to have no effect on the Mg level in kidneys and hepatic tissue, whereas the Fe level in those tissues was significantly diminished by increasing dietary Mg supplementation up to 3.2 g.kg-1. Both hypercalcinosis and accumulation of Fe in soft tissues were more pronounced in fish offered diets high in protein (44%) compared to fish on low dietary protein (25%). The ascorbic acid in the hepatopancreas and kidney was greatly depleted in fish fed the high-protein diets, and this depletion did not correlate with the dietary Mg level nor with a high level of tissue Ca. However, the increased Ca concentration in the kidney coincided with the greatest depletion of ascorbate in fish fed a high-protein diet. The concentration of ascorbate in the brain was much less affected by a low level of vitamin C in the diets than in other tissues. Depletion of ascorbate in soft tissues did not correspond to fish growth but might be rather related to the metabolic rate imposed by the dietary nutrients. It is suggested that the Mg and ascorbic acid requirements in the carp are considerably elevated by the increased dietary protein level.

Animals↗
PubMed1989

Applications of a simultaneous assay of ascorbic acid, dehydroascorbic acid and ascorbic sulphate in biological materials.

A modified spectrophotometric assay for ascorbic acid and its derivatives based on their reaction with 2,4-dinitrophenylhydrazine (DNPH) is described. Using standard ascorbic acid or ascorbic sulphate solutions, together with animal tissue or compound diet extracts, the conditions for ascorbic acid degradation were determined. For the differential measurement of reduced ascorbic acid (AA), dehydroascorbic acid (dAA) and ascorbic sulphate (AS), five series of simultaneous determinations were performed. These included the use of (1) KBrO3 for the hydrolysis of AS, (2) 2,6-dichlorophenolindophenol as an oxidant, (3) DNPH to form a hydrazone derivative with dAA and (4 and 5) two blanks (where ascorbate was degraded) to correct for interfering substances. A variety of vertebrate and invertebrate tissues were examined for their ascorbate content, and the advantages of the modified procedure over currently available assays are discussed. The results suggest that the Artemia cyst is a unique material in which ascorbic sulphate is present in large amounts whereas fish tissues do not contain this form of vitamin C.

Animals↗
PubMed1989

The effect of ascorbate on proteolytic enzyme activities in fish.

In vitro studies showed that an ascorbic acid concentration of 15 mM depressed the trypsin activity in three fish species by 50%, whereas dehydroascorbic acid and ascorbic sulfate did not inhibit trypsin or chymotrypsin activities. However, this inhibitory action is unlikely in vivo because ascorbic acid is rapidly oxidized in the digestive tract content to the dehydroascorbic acid.

Animals↗
PubMed1988

Absorption of intact proteins by the intestinal epithelium of trout, Salmo gairdneri. A luminescence enzyme immunoassay and cytochemical study.

In the rainbow trout, a carnivorous species with a stomach, orally administered horseradish peroxidase (HRP) crossed the intestinal epithelium into the circulation. The protein first appeared in the blood 7 to 8 h after intubation, and could be assayed up to 24 h after administration. The method used, which combines ELISA (enzyme-linked immunoabsorbant assay) and chemiluminescence, enabled the transfer to be measured quantitatively. There was a direct correlation between the quantity ingested and the quantity transferred to the plasma within the experimental limits chosen. The clearance was monophasic and exponential (clearance rate: 3% per minute). Up to 6% of the ingested HRP was transferred to the blood. By cytochemistry it was possible to demonstrate that the protein crossed the intestinal cells at the level of the posterior segment, escaping the particularly intense intracellular lysosomal digestion. After entering the intercellular space, HRP was transferred to the interstitial space of the subepithelial lamina propria. During this transfer the HRP was in close contact with infiltrated macrophages and leukocytes resembling lymphoid cells. Thus, the passage of these protein particles could be the first indispensable step in the possible triggering of a local and/or a systemic immune response.

Animals↗
PubMed1986

Protein digestion and amino acid absorption along the intestine of the common carp (Cyprinus carpio L.), a stomachless fish: an in vivo study.

Protein hydrolysis to peptides and free amino acids and the apparent absorption of amino acids (AAaa) were evaluated in different segments of carp intestine. The AAaa analysed using Cr2O3 as a marker indicated that 73.2% of the amino acids were absorbed in the first 20% of the intestinal tract and 5.3 and 21.5, respectively, in the following segments (20% of gut length). Except for methionine and histidine, essential free amino acid concentration decreased significantly along the intestine. Of the nonessential amino acids, glutamate and aspartate concentrations increased in the hind gut. The absolute amount of the peptide amino acid fraction decreased towards the middle intestine but, expressed as a proportion of the total amino acid content, it changed little along the intestine: 49 and 54% in the anterior and posterior intestine, respectively. The molar concentration of the peptide amino acid fraction was much higher in carp intestine (543.9 mM) than in rainbow trout (147.3 mM) or human (143.9 mM) intestine.

Amino Acids↗