Biomedical subjects

M Kirchgessner

Publications and source records attributed to M Kirchgessner.

At least 19 recordsLinked to original sources

PubMed2002

Selenium supplementation and selenium status of dairy cows fed diets based on grass, grass silage or maize silage.

In three separate trial series (TS) the effect of diet composition on selenium (Se) status of dairy cows were investigated. Diets were formulated based mainly on grass (TS1), grass silage (TS2) or maize silage (TS3) with different levels of Se supplementation. Each TS comprised a total of 30 dairy cows and contained one treatment group without Se supplementation (control) and two groups with increasing levels of Se supplementation (levels 1 and 2). Selenium was administered as Na-selenite. The control groups of the different TS showed a very low Se supply of 38-54 microg Se/kg DM. At level 1 the Se supply was increased to 102-165 microg Se/kg DM and at level 2 was 294-373 microg Se/kg DM. After completion of the 6-week trials the average plasma Se concentration of the control cows (without Se supplementation) across all TS was 21.5 microg/l; this increased significantly following Se supplementation, to 37.7 microg/l at level 1 and 61.5 microg/l at level 2. The plasma glutathione peroxidase (GSH-Px) activity of the control cows averaged 67 U/l, rising considerably after supplementation at level 1 to a value of 101 U/l, but showed little further increase at level 2 with a mean value of 120 U/l. By contrast, the average Se content of the milk was unchanged in the control and level 1 groups at 10.5 microg/kg and 10.9 microg/kg, respectively, and only increased markedly after supplementation at level 2 to a mean value of 15.1 microg/kg. The diet based on maize silage, while having a similar Se content as the grass and grass silage-based diets, resulted in a slightly improved Se status, which is due to a higher Se intake from soybean meal.

Animal Feed↗

PubMed2000

Separation and quantitation of metallothionein isoforms from liver of untreated rats by ion-exchange high-performance liquid chromatography and atomic absorption spectrometry.

A sensitive method for determination of metallothionein (MT) isoform levels in rat liver by ion-exchange high-performance liquid chromatography and atomic absorption spectrometry was developed. Critical steps in sample preparation, like MT extraction, MT saturation with Cd and protein separation, were optimized. This method is capable of measuring levels of 2.0 microg/g liver for metallothionein-1 (MT-1) and 1.3 microg/g liver for metallothionein-2 (MT-2), respectively, with a high recovery of 103% on average. The method described, thus, proved suitable for analyzing metallothionein isoform concentrations even in untreated animals. The ratio of MT-1 to MT-2 was found to be 1:1 on average. MT decomposition during storage was very high in whole livers, but could be reduced by about 80% when extracted liver samples were used.

Animals↗

PubMed2000

Abnormal activity of membrane phospholipid synthetic enzymes in the brain of patients with Friedreich's ataxia and spinocerebellar atrophy type-1.

Much evidence, derived from biochemical studies of both blood and autopsied brain, has suggested that phospholipid metabolism is abnormal in patients with Friedreich's ataxia (FA), a disorder characterized by severe neuronal loss in the spinal cord and lower brain stem with no, or only modest, damage in other brain regions. To establish the cause of our recent finding of reduced brain levels of phospholipids in FA, we assayed activities of 10 phospholipid-metabolizing enzymes in the autopsied cerebellar cortex of patients with the disorder and, for comparison, in a group of patients with spinocerebellar ataxia type 1 (SCA-1), a disease characterized, unlike FA, by marked neuronal loss in the cerebellar cortex. Enzyme activities were also measured in four brain areas which are relatively unaffected morphologically in both FA and SCA-1. We found that ethanolamine kinase activity was increased in multiple brain regions of patients with FA (increased 31%-137%) and, more modestly, in SCA-1 (increased 39%-60%), suggesting a nonspecific enhancement of phosphoethanolamine production in both disorders. In contrast, the activity of phosphoethanolamine cytidylyltransferase (PECT), the rate-limiting enzyme of phosphatidylethanolamine synthesis, was significantly and markedly decreased by 35%-78% in the cerebellar, frontal, and occipital cortices of patients with FA but was normal in SCA-1. Reduced PECT activity in FA may explain the lower brain levels of phosphatidylethanolamine in the disorder. Moreover, because decreased PECT activity in FA occurs in brain regions having no, or only modest, morphologic damage, this may represent a systemic change consequent to the frataxin gene defect. Our data also suggest that therapeutic intervention in FA designed to increase synthesis of membrane phospholipids may warrant further investigation.

Adult↗

PubMed2000

Chronic vitamin E inadequacy and thermally treated oils affect the synthesis of hepatic metallothionein isoforms.

BACKGROUND: Metallothionein (MT)# synthesis can be stimulated in many organs not only by various metals such as cadmium, zinc, and copper, but also by many nonmetallic compounds or experimental conditions such as oxidative stress. The latter lead to the hypothesis that MT is induced in response to free radicals formed in tissues and lipid peroxidation. AIMS OF THE STUDY: Whether the relationship between lipid peroxidation and MT synthesis is a common phenomenon also valid for lipid peroxidation induced by dietary factors such as chronic vitamin E inadequacy and autoxidation products of polyenoic fatty acids derived from thermally oxidized oil was investigated in the present study. METHODS: The relationship between the induction of metallothionein isoforms I and II (MT-I and MT-II) in response to diet-induced lipid peroxidation using a rat model system in which lipid peroxidation was examined in vivo by chronic vitamin E inadequacy or by administration of lipid peroxidation products from a thermally treated polyenoicrich oil with either basal (dietary zinc concentration: 48 mg/kg; experiment 1) or Zn-stimulated MT levels (dietary zinc concentration: 305 mg/kg; experiment 2) was studied. In both experiments, growing male rats were fed diets containing either a fresh or a thermally treated soybean oil with deficient or sufficient amounts of vitamin E (14 and 11 vs. 648 and 560 mg alpha-tocopherol equivalents per kg diet) over 40 days according to a bifactorial experimental design. Plasma and liver concentrations of tocopherols and hepatic levels of thiobarbituric acid-reactive substances (TBARS) were measured by high performance liquid chromatography. MT isoform concentrations in rat liver were isolated and quantified by ion-exchange high performance liquid chromatography and atomic absorption spectrometry. RESULTS: Irrespective of the zinc supply, rats receiving inadequate amounts of vitamin E with the diet had markedly lower plasma and liver concentrations of alpha-tocopherol and total tocopherols than vitamin E-sufficient rats. ANOVA also revealed an interaction between the diet factors vitamin E and oil on tocopherols in plasma and liver of rats from both experiments. In experiment 1, where rats received normal amounts of dietary zinc, ingestion of the thermally treated oil impaired the tocopherol status compared to the treatment with the fresh oil, although this effect was only obvious in the vitamin E-deficient groups. In experiment 2, where rats received excessive amounts of zinc, the thermally treated oil did not contribute to a reduction of the tocopherol status in plasma and liver. In both experiments a significant increase in TBARS level, indicative of lipid peroxidation, was observed in the liver at chronic vitamin E inadequacy, but no effect of the oil was observed. Here, we show that the dietary treatments had some effects on the synthesis of liver metallothionein isoforms. In groups, receiving normal amounts of zinc, there was a significant interaction between the dietary treatments on the levels of MT-I and MT-II in liver. Chronic vitamin E inadequacy which was accompanied by diminished tocopherol levels in liver induced the synthesis of MT-I and MT-II. When vitamin E inadequacy was combined with the ingestion of a thermally treated polyenoic acid-rich oil hepatic levels of MT-I and MT-II remained low. In experiment 2, where rats were fed the high zinc diet, vitamin E inadequacy caused an increase of hepatic MT-I level just as in experiment 1, although this MT stimulating effect was irrespective of the oil. For MT-II there was a 43% increase in the vitamin E-deficient group fed the fresh oil compared to all the other groups, although this effect was not statistically significant. The liver MT isoform response to stress was similar in rats with basal MT levels and Zn-induced liver MT levels. The failing effect of the thermally treated oil on MT levels which were stimulated by vitamin E deficiency in experiment 2 wa

Animals↗

PubMed2000

Zinc deficiency and the activities of lipoprotein lipase in plasma and tissues of rats force-fed diets with coconut oil or fish oil.

The present study was performed to investigate the effect of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and tissues of rats fed diets containing either coconut oil or fish oil as dietary fat, using a bifactorial experimental design. To ensure an adequate food intake, all the rats were force-fed by gastric tube. Experimental diets contained either 0.8 mg zinc/kg (zinc-deficient diets) or 40 mg zinc/kg (zinc-adequate diets). The effects of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and postprandial triglyceride concentrations and distribution of apolipoproteins in serum lipoproteins depended on the type of dietary fat. Zinc-deficient rats fed the coconut oil diet exhibited a reduced activity of lipoprotein lipase in postheparin serum and adipose tissue, markedly increased concentrations of triglycerides in serum, and a markedly reduced content of apolipoprotein C in triglyceride-rich lipoproteins and high density lipoproteins compared with zinc-adequate rats fed coconut oil. By contrast, zinc-deficient rats fed the fish oil diet did not exhibit reduced activities of lipoprotein lipase in postheparin serum and adipose tissue and increased concentrations of serum lipids compared with zinc-adequate rats fed the fish oil diet. This study suggests that a reduced activity of lipoprotein lipase might contribute to increased postprandial concentrations of serum triglycerides observed in zinc-deficient animals. However, it also demonstrates that the effects of zinc deficiency on lipoprotein metabolism are influenced by dietary fatty acids.

Journal Article↗

PubMed2000

Cobalt-deficiency-induced hyperhomocysteinaemia and oxidative status of cattle.

In ruminants, Co is required for the synthesis of vitamin B12, which in turn is needed for the resynthesis of methionine by methylation of homocysteine and thus, cobalamin deficiency may induce hyperhomocysteinaemia which is brought into context with perturbations of the antioxidative-prooxidative balance. The present study was conducted to explore whether Co deficiency in cattle is also associated with homocysteine-induced disturbances of oxidative status. Co deficiency was induced in cattle by feeding two groups of animals on either a basal maize-silage-based diet that was moderately low in Co (83 micrograms Co/kg DM), or the same diet supplemented with Co to a total of 200 micrograms Co/kg DM, for 43 weeks. Co deficiency was apparent from a reduced vitamin B12 status in serum and liver and an accumulation of homocysteine in plasma which was in excess of 4.8 times higher in Co-deprived cattle than in controls. The much increased level of circulating homocysteine did not indicate severe disturbances in antioxidant-prooxidant balance as measured by individual markers of lipid peroxidation, protein oxidation, and the antioxidative defence system. There were no quantitative difference in plasma thiol groups, nor were there significant changes in concentrations of alpha-tocopherol, microsomal thiobarbituric acid-reactive substances and carbonyl groups in liver. However, there was a trend toward increased plasma carbonyl levels indicating a slight degradation of plasma proteins in the hyperhomocysteinaemic cattle. Analysis of the hepatic catalase (EC 1.11.1.6) activity revealed an 11% reduction in Co-deficient cattle relative to the controls. These results indicate that long-term moderate Co deficiency may induce a severe accumulation of plasma homocysteine in cattle, but considerable abnormalities in oxidative status failed to appear.

Animals↗

PubMed2000

Evaluation of the cobalt requirement of beef cattle based on vitamin B12, folate, homocysteine and methylmalonic acid.

This investigation was designed to estimate the Co requirement of growing cattle on the basis of plasma and liver levels of vitamin B(12) and folate, plasma levels of homocysteine and methylmalonic acid (MMA) and haematological variables. For this purpose thirty-four male intact cattle of the German Simmental breed (236 kg) were assigned randomly to ten groups and were fed corn silage-based diets which contained 70, 90, 109, 147, 184, 257, 327, 421, 589 or 689 microg Co/kg DM for 40 weeks. One-slope broken-line model analysis and a quadratic model with plateau were used to estimate the Co requirement. The broken-line model estimated the dietary Co requirement of growing cattle to be 257 (se 29) microg/kg dietary DM based on plasma vitamin B(12) as response criterion. The dietary Co levels needed to maximise the liver vitamin B(12) and liver folate were 236 (se 8) and 190 (se 8) microg/kg dietary DM respectively. Plasma folate did not show any response to the different Co levels. The dietary Co was inversely correlated with the plasma concentrations of homocysteine and MMA. Estimates of the dietary Co concentration required to minimise homocysteine were 161 (se 10) microg/kg DM. When MMA was used as response criterion, the linear model yielded a Co requirement of 124 (se 3) microg/kg dietary DM. The quadratic model did not provide a better closeness of regression fit and yielded similar requirements to the linear model. Haemoglobin concentration and haematocrit tended to have a slight response to increasing dietary Co and were only decreased in cattle on diets containing less than 100 microg Co/kg DM. On the basis of the present data, recommended levels of dietary Co for normal folate metabolism and minimum homocysteine and MMA levels can be set to be 150-200 microg/kg DM; for maximum vitamin B12 levels, the desired Co content in the diet seems to be 250 microg/kg DM.

Animals↗

PubMed2000

Precaecal digestibility of niacin and pantothenic acid from different foods.

This study was conducted to investigate the apparent precaecal digestibilities of niacin and pantothenic acid from human nutrient related foods including wheat, coarse whole-meal bread, boiled potatoes and boiled pork and beef. Therefore, pigs were subjected to an end-to-end ileo-rectal anastomosis, so digesta passed straight from ileum to rectum, eliminating endogenous vitamin synthesis. Excreted chyme was collected over 5-days periods, and concentrations of niacin, and pantothenic acid in the food and chyme samples were determined microbiologically. The intestinal bioavailability of niacin and pantothenic acid was affected differently by the food administered. The digestibility values of niacin deriving from the wheat-, potato- and the meat-based meals ranged from 59 to 69%. Wholemeal bread exerted a nutritionally important negative effect on the apparent intestinal availability of dietary niacin relative to the other foods, which averaged by 40%. Food-related differences of the pantothenic acid digestibility values were greater than that observed with niacin. The digestibility values of pantothenic acid from wheat, potatoes and the meat meals ranged between 65 and 81% and were of the order wheat diet > pork diet > potato diet > beef diet, although differences were not statistically significant. The digestibility of pantothenic acid from the coarse wholemeal bread diet was lower than 30%.

Animals↗

PubMed2000

Influence of the dietary ratio between sulphur containing amino acids and lysine on performance of growing-finishing pigs fed diets with various lysine concentrations.

This study was conducted to determine the optimal ratio between sulphur containing amino acids and lysine in diets for growing-finishing pigs. Therefore, a total of five trials was carried out in which growing-finishing pigs (live weight range between 53 and 105 kg) were fed diets with various concentrations of lysine (0.62, 0.70 and 0.78%) and various ratios between sulphur containing amino acids to lysine. The diets contained 12.9 MJ ME per kg and 13.5% CP; the ratio between sulphur containing amino acids to lysine was adjusted by individual supplementation of the diets with DL-methionine. Increasing dietary levels of lysine from 0.62 to 0.78% continuously increased daily body weight gains and improved feed conversion efficiency as well as carcass characteristics. There was no significant interaction between the dietary lysine supply and the ratio between sulphur containing amino acids to lysine on animal performance parameters. This means that the effect of the ratio of sulphur containing amino acids to lysine was similar for various dietary lysine concentrations. The optimum ratio between sulphur containing amino acids to lysine according to quadratic regression analysis was 0.60, for both, growth and feed conversion. Reducing the ratio between sulphur containing amino acids to lysine from 0.59 to 0.53 and 0.47 reduced body weight by 3 and 12%, resp., and elevated the feed conversion ratio by 2 and 12%, resp. An increase of the ratio between sulphur containing amino acids to lysine from 0.59 to 0.65 failed to increase the animal performance. In contrast to animal performance parameters, optimum carcass characteristics (eye muscle area, fat area above eye muscle, meat-fat ratio and lean percentage) were achieved already at a ratio of sulphur containing amino acids to lysine of 0.53.

Amino Acids, Sulfur↗

PubMed2000

Effects of vitamin B6 supplementation in rats during lactation on vitamin B6 concentration and transaminase activities in the offspring.

The aim of the present investigation was to study the effect of a varying maternal vitamin B6 supplementation during lactation period on vitamin B6 levels in blood, liver and total body, and on the activity of two transaminase enzymes in the offspring. Therefore, eighty female Sprague-Dawley rats were fed a semi-synthetic diet (0.2 mg vitamin B6 per kg) which was supplemented during gravidity with 5 mg vitamin B6 per kg diet. During the following lactation period the rats were assigned to one of 10 vitamin B6 treatment groups (supplementation of 0, 3, 6, 9, 12, 15, 18, 36, 360, 3600 mg vitamin B6 per kg diet). At day 14 of lactation the pubs of all dams were decapitated and blood, liver, and carcass were used for analysis of vitamin B6 concentration, activities of two transaminases, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in plasma, erythrocytes, and liver, and of haematological parameters. While the liver and total body wet weights as well as the haematological parameters (red blood cells, haemoglobin concentration, hematocrit, middle corpuscular cell volume, middle corpuscular haemoglobin, middle corpuscular haemoglobin concentration) did not differ within the experimental groups, the present data clearly show that in blood, liver and total body of the offspring exists a slight dose-response relationship between the maternal dietary vitamin B6 supplementation and the vitamin B6 concentration. Concerning the activities of the transaminases a dietary supplementation above 3 mg vitamin B6 per kg diet had no influence on the AST and ALT activities in offspring plasma. In the erythrocytes no statistical significant influence of the vitamin B6 supplementation during lactation on the activities of AST and ALT was found. The activities of ALT and AST in liver were not consistently altered by the vitamin B6 supplementation of the dams during lactation. In conclusion these results indicate that a minimal maternal dietary vitamin B6 supply of 3.1 mg per kg diet is necessary with regard to health and development of their offspring. But not all of the analysed parameters as the liver and total body weights, the activities of AST and ALT in the erythrocytes, and the haematological parameters were influenced by a deficient maternal dietary vitamin B6 supply.

Alanine Transaminase↗

PubMed2000

Vitamin B-12 deficiency and hyperhomocysteinemia are partly ameliorated by cobalt and nickel supplementation in pigs.

Vitamin B-12 deficiency and hyperhomocysteinemia alter the metabolism of trace elements. This study tested the hypothesis that there is a reverse relationship in which diets high in iron, copper, nickel and cobalt would influence vitamin B-12 deficiency outcomes including hyperhomocysteinemia. Piglets (German Landrace x Pietrain) were assigned to six groups of 8 and fed one of the following diets for 166 d: a vitamin B-12-adequate and folate-fortified diet (30 microg/kg vitamin B-12 and 0.5 mg/kg folate) with normal trace element concentrations or one of five vitamin B-12-free, folate nonsupplemented diets (0.36 mg/kg), with either normal trace element concentrations or high concentrations of iron (300 mg/kg), copper (30 mg/kg), cobalt (1 mg/kg) or nickel (6 mg/kg). Feed intake and weight gain did not differ significantly among the groups. Vitamin B-12-deficient pigs developed diminished serum and liver concentrations of vitamin B-12 and folate, an accumulation of iron in the liver and hyperhomocysteinemia. The magnitude of changes differed among vitamin B-12-deficient groups. Vitamin B-12-deficient pigs fed 6 mg/kg nickel had distinctly higher vitamin B-12 concentrations in liver and serum and 45% lower serum concentration of homocysteine than the corresponding deficiency group fed 1 mg/kg nickel; iron concentration in liver was completely normalized. Vitamin B-12-deficient pigs fed 1 mg/kg cobalt had 47% lower homocysteine concentrations in serum than the vitamin B-12-deficient group fed 0.13 mg/kg cobalt, but the vitamin B-12 status was unaffected. Supplementation of iron and copper did not affect these variables. The dietary manipulations had no detrimental effects on variables symptomatic of oxidative stress. The findings indicate a collaborative relationship between vitamin B-12 metabolism and the trace elements nickel and cobalt.

Animal Feed↗

PubMed1999

[Diagnosis of zinc deficiency].

Though far more common, particularly in elderly people, than was previously assumed, marginal zinc deficiency does not lead to the classical manifestations of zinc deficiency and is therefore difficult to diagnose. There is therefore a need for sensitive parameters that can reliably demonstrate even marginal zinc deficiency, as suboptimal zinc status can seriously impair human health, performance, reproductive functions, and mental and physical development. The most important criteria for the diagnosis of zinc deficiency are critically discussed. The laboratory parameters currently considered to be the most useful indicators of marginal zinc deficiency are zinc-binding capacity and serum/plasma alkaline phosphatase activity before and after zinc supplementation (zinc tolerance test!). In order to obtain a reliable assessment of a patients zinc status, a number of different diagnostic parameters should always be measured.

Aged↗

PubMed1999

Investigations on the intestinal availability of native thiamin in selected foods and feedstuffs.

The aim of the present study was to investigate the precaecal digestibility as a quantitative measure for the intestinal availability of naturally occurring thiamin from selected foods and feedstuffs. Therefore, three experiments were conducted to examine the following foods and feedstuffs: Eggs, bananas, white cabbage, corn, milk, fish, barley, soybeans, rice, wheat bran, brewer's yeast, rye and soybean meal. The foods and food processing procedures were made with regard to their relevance in human and animal nutrition. For all experiments male pigs with an initial live weight between 33 and 40 kg were fitted with an end-to-end ileo-rectal anastomosis with preserved ileo-caeco-colicvalve. Three weeks after surgery, the digestibility trials were carried out from week 4 to week 9 and week 12 to week 17 after surgery. The animals were fed the individual experimental diets for a period of 12 days while digesta were collected twice a day quantitatively during the final 5 days of this period. Precaecal digestibility for thiamin from all tested foods and feedstuffs was within a range from 73% to 94% with the highest values from boiled soybeans, boiled rice and barley, and the lowest value from steamed fish. In comparison with the animal products the plant products show on average a nearly equal precaecal digestibility for thiamin (87.3% versus 83.5%). Moreover, all tested foods and feedstuffs exhibit a relatively good intestinal availability of thiamin.

Animal Feed↗

PubMed1999

Conjugated linoleic acid effects on circulating hormones, metabolites and lipoproteins, and its proportion in fasting serum and erythrocyte membranes of swine.

BACKGROUND: Conjugated linoleic acids (CLA)# refer to a group of linoleic acid (18:2)-derived isomers with conjugated double bonds mostly at carbon atoms 9 and 11 or 10 and 12, and with all possible cis and trans combinations. CLA is a newly recognized nutrient that functions to regulate energy retention and metabolism and that causes a serum lipoprotein profile considered to be less atherogenic. However, rodent models that have been frequently used for these studies are only of limited use because of distinct differences in physiology, compared with man. Additionally, possible differences in food intake between the experimental groups remained often unconsidered in those studies. Thus, it can not be excluded that the beneficial effects of CLA reported in a series of studies may be due, at least partially, to differences in nutrient and energy ingested. AIMS OF THE STUDY: This prompted us to undertake an investigation on the action of CLA by using a pig model and a feeding regimen with controlled amounts of food and antioxidants. The parameters used to assess CLA-specific action were selected hormones and metabolites involved in energy metabolism, individual lipoproteins and the appearance of CLA in fasting serum and erythrocyte membranes. Blood as an easily available biological sample was used for investigation. METHODS: For that purpose 16 adult female pigs were divided into two groups of 8 each, and were isoenergetically fed diets containing 0 (control diet) or 1% level of CLA (by weight) for 6 weeks. Plasma concentrations of total and free thyroxine (T4), total and free triiodothyronine (T3), and insulin were measured by radioimmunoassays. Plasma non-esterified fatty acids (NEFA), beta-hydroxybutyrate, circulating blood ATP and other clinical chemical variables were determined using enzymatic assays. The concentration of alpha-tocopherol was determined by high performance liquid chromatography. The lipoproteins VLDL (density <1.019 kg/L), LDL (density 1.019 - 1.063 kg/L), and HDL (density >1.063 kg/L) were isolated by step-wise ultracentrifugation. Fatty acids of the dietary oils, serum and blood cell membranes were separated and quantified by gas chromatography. RESULTS: At week 6, body weights of the pigs fed the CLA-supplemented diet were not different from that of the controls. CLA-treated pigs exhibited a 37% higher concentration of fasting serum insulin than their controls receiving no CLA (P = 0.11). Circulating free and total T4 and T3 as well as serum levels of beta-hydroxybutyrate, alpha-tocopherol, protein, glucose, urea, creatinine and circulating blood ATP remained unaffected by CLA supplementation. Serum concentrations of non-esterified fatty acids were reduced by 38% in CLA-treated pigs relative to the controls, although this difference was not significant. CLA-treated pigs tended to have lower leukocyte counts in blood than their controls (P <0.1). Erythrocyte and platelet counts, the hematocrit and hemoglobin concentration were similar between the groups. Serum of CLA-treated pigs showed a trend toward increased levels of triacylglycerols, cholesterol and phosphatidylcholine in the very low density and low density lipoproteins (LDL), without distinct changes in the high density lipoprotein fraction (HDL). The LDL cholesterol to HDL cholesterol ratio was significantly increased by CLA. When pigs were fed CLA at a dietary level of 1%, limited proportions of CLA appeared in fasting serum (1.6%) and erythrocyte membranes (1.1%). CONCLUSIONS: Under the present experimental conditions there appeared to be parallels between the effects of CLA and the reported effects of trans fatty acids in the mode of action on lipoproteins and insulin. The failure to demonstrate significant beneficial effects of CLA on the lipoprotein profile which have been observed in other studies requires further research.

3-Hydroxybutyric Acid↗

PubMed1999

Changes in the odorants of boiled carp fillet (Cyprinus carpio L.) as affected by increasing methionine levels in feed.

Sixty common carp in groups of five in four tanks per treatment were given three diets containing different increasing amounts of methionine. The aroma extract dilution analysis (AEDA) of the boiled carp fillets resulted in 32 odorants, of which 26 were identified. Ten compounds were quantified using an internal standard (IS), and the very low concentrations of 2-acetyl-1-pyrroline, (Z)-1, 5-octadien-3-one, and methional were calculated by the nasally determined detection limit. The concentration of methional seemed to increase with increasing methionine in the diet. Because the unstable methional could be converted by beta-elimination into methanethiol, the impact resulting in an off-flavor was investigated by headspace analysis. The investigation revealed no difference in the methanethiol contents between the treatments with the lowest and highest methionine supplies.

Animal Feed↗

PubMed1999

Cobalt deficiency effects on trace elements, hormones and enzymes involved in energy metabolism of cattle.

This study was conducted to investigate the physiological consequences of long-term moderate cobalt deficiency in beef cattle, which have not hitherto been studied in detail. Cobalt deficiency was induced in cattle by feeding two groups of animals either a basal corn silage-based diet that was moderately low in cobalt (83 micrograms Co/kg), or the same diet supplemented with cobalt to a total of 200 micrograms per kg, for 43 weeks. Cobalt deficiency was induced, as judged by inappetance, diminished growth gain and a markedly reduced vitamin B12 status in serum and liver. The long-term cobalt deprivation which was primarily a combination of reduced feed intake and a tissue vitamin B12 deficiency did not show evidence of a significant dysfunction of energy metabolism. The activities of glucose-6-phosphate dehydrogenase and cytochrome oxidase in liver remained unaffected by cobalt deficiency, nor was there a significant change in serum glucose level of cattle on the cobalt-deprived diet. However, analysis of thyroid hormone status indicated a slight reduction of type I thyroxine monodeiodinase activity in liver accompanied by a significant reduction of the triiodothyronine level in serum. The diminished liver vitamin B12 level resulted in significantly reduced folate level in this tissue, reduced concentrations of heme-depending blood parameters. Moreover cobalt deficiency or rather vitamin B12 deficiency was accompanied by a dramatic accumulation of the trace elements iron and nickel in liver. These results indicate that long-term moderate cobalt deficiency may induce a number of physiological changes in cattle, but a follow-up study, which excluded different feed levels by including a pair-fed control group, will be necessary to actually obtain the single effect of cobalt deficiency in cattle.

Animals↗

PubMed1998

Brain phospholipids and fatty acids in Friedreich's ataxia and spinocerebellar atrophy type-1.

Previous studies of patients with spinocerebellar atrophy type 1 (SCA-1) and Friedreich's ataxia (FA) have suggested the occurrence of membrane disturbances in both disorders. We measured concentrations of phosphatidylcholine (PC), diacyl and plasmalogen phosphatidylethanolamine (PE), and phosphatidylserine (PS), along with their fatty acid profiles, in the brains of eight patients with Friedreich's ataxia (FA) and nine patients with dominantly inherited spinocerebellar atrophy type 1 (SCA-1). Compared with the controls, levels of all phospholipid types (PE, PS, and PC) were reduced in the cerebellar but not occipital cortex of SCA-1 patients. In contrast, in the FA group, levels of PS and PE, but not PC, were reduced in both cerebellar and occipital cortices. The fatty acid composition of individual brain phospholipids was altered in both FA and SCA-1 patients, most markedly in the plasmalogen PE and PS classes of cerebellar phospholipids. Given the neuropathologic characteristics of each disorder, it is likely that altered fatty acid composition and phospholipid levels in SCA-1 cerebellar cortex occur as a consequence of pronounced cerebellar degeneration. In contrast, reduced phospholipid levels in FA cerebellar and occipital cortex, areas characterized by, at most, minimal neuronal loss in FA, may represent a widespread alteration in cellular phospholipid metabolism occurring in response to the specific gene defect in the disorder.

Adult↗

PubMed1998

Nickel deficiency alters nickel flux in rat everted intestinal sacs.

This study was conducted to determine nickel absorption in nickel-deficient rats. Jejunal segments obtained from dietary nickel-depleted (13 microg nickel/kg diet) and nickel-control (1 mg nickel/kg diet) adult rats from the first generation, and suckling pups from the second offspring were used. The nickel transfer across the intestinal epithelium and nickel uptake into the intestine were measured by use of everted jejunal sacs using a wide range of nickel concentrations administered on the luminal side (1.1 x 10(-8) M til 1.0 x 10(-4) M). Both the intestinal nickel transfer and nickel uptake were influenced by the dietary nickel supply in rat offspring, but not in the adult rats from the first generation. However, in nickel-deficient offspring, the nickel transfer across the small intestine was higher than in nickel-control offspring. This difference was greater using low intraluminal nickel concentrations than high nickel concentrations, and was significant at 1.1 x 10(-8) M, 6.1 x 10(-8) M, 5.1 x 10(-7) M, 1.0 x 10(-6) M, and 5.0 x 10(-6) M. Also, nickel uptake into the intestine was somewhat greater in nickel-deficient rat pups than in nickel-control pups, and significant using 1.1 x 10(-7) M and 1.0 x 10(-6) M nickel. A definite saturation type kinetic for the intestinal nickel absorption in relation to the intraluminal nickel concentration could not be observed.

Animals↗