Effect of dietary fatty acid pattern on growth, body fat composition and antioxidant parameters in broilers.

The effects of dietary fat supplementation on performance, fatty acid (FA) composition of tissues and antioxidant defence system of broilers were studied. Male broilers were placed in 20 floor pens (60 broilers per pen). The broilers were fed by diets with added different energy sources: lard (L); sunflower oil (SFO); soybean oil (SBO); and linseed oil (LSO). The treatments did not modify significantly growth performance and feed intake of the broilers. There was no effect of dietary FA pattern on reduced glutathione level and glutathione peroxidase activity of plasma, erythrocyte and liver samples. However, higher PUFA content of the diet resulted in a significant increase in malondialdehyde level of erythrocytes and liver. The broilers fed LSO diet more effectively maintained their antioxidant status with enhanced plasma radical scavenger capacity. FA composition in tissues reflected the FA pattern of the diets, although proportion of FAs with four or more double bonds was metabolic specific. LSO diet increased the level of C18:3, C20:5 and C22:6 in tissue lipids in relation to L, SFO and SBO diets. Significantly increased plasma radical scavenging capacity in concert with the enhanced C20:5 and C22:6 proportion in liver and muscle during LSO feeding indicate metabolic changes to counteract the oxidative injury. This may be related to the compounds produced after different biochemical pathways of n-6 and n-3 FAs.

Occupational exposure to polycyclic aromatic hydrocarbons in a fireproof stone producing plant: biological monitoring of 1-hydroxypyrene, 1-, 2-, 3- and 4-hydroxyphenanthrene, 3-hydroxybenz(a)anthracene and 3-hydroxybenzo(a)pyrene.

OBJECTIVES: Assessment of external and internal exposure to polycyclic aromatic hydrocarbons (PAH) in a fireproof stone producing plant. METHODS: Five personal and four stationary air measurements were performed to determine the concentrations of benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, phenanthrene and pyrene, in air. To estimate internal exposure, we determined the urinary excretion of 1-hydroxypyrene, 1-, 2-, 3-, and 4-hydroxyphenanthrene, 3-hydroxybenz(a)anthracene and 3-hydroxybenzo(a)pyrene in 19 workers, using a sensitive and reliable high-performance liquid chromatographic method with fluorescence detection. RESULTS: During the production of fireproof stones, the German technical exposure limit (TRK) for benzo(a)pyrene of 2 microg/m3 was exceeded in two cases. The mean values of the sum of eight PAHs were 12.6 microg/m3 (stationary air measurement) and 22.2 microg/m3 (personal air measurement). Urinary 1-hydroxypyrene excretion predominated, with a median of 11.1 microg/g creatinine (creat.), followed by 3-hydroxyphenanthrene (median 2.2 microg/g creat.), 1-hydroxyphenanthrene (median 1.9 microg/g creat.) and 2-hydroxyphenanthrene (median 1.6 microg/g creat.). 4-Hydroxyphenanthrene (median 0.3 microg/g creat.) and 3-hydroxybenz(a)anthracene (median 0.17 microg/g creat.) were found in far lower concentrations, while 3-hydroxybenzo(a)pyrene was found only in very low concentrations (median 0.014 microg/g creat.). No correlations could be detected for a relationship between external and internal exposure. A significant correlation between urinary metabolite concentrations could be calculated only for 3-hydroxybenz(a)anthracene and 1-hydroxypyrene. CONCLUSIONS: In comparison with other industries, the internal PAH exposure at workplaces in a fireproof stone producing plant is high. This is probably caused by dermal PAH-absorption. Therefore, biological monitoring must be performed in the health surveillance of fireproof stone producing workers. The urinary PAH metabolites should be determined: 3-hydroxybenz(a)anthracene could probably be used as a biomarker representing the group of carcinogenic PAH.

High-performance liquid chromatographic method with fluorescence detection for the determination of 3-hydroxybenzo[a]pyrene and 3-hydroxybenz[a]anthracene in the urine of polycyclic aromatic hydrocarbon-exposed workers.

The described high-performance liquid chromatographic method with fluorescence detection (HPLC-FD) permits the simultaneous determination of 3-hydroxybenzo[a]pyrene and 3-hydroxybenz[a]anthracene as the most important metabolites of the carcinogenic polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene and benz[a]anthracene in human urine. After enzymatic hydrolysis, to release the conjugated metabolites, the analytes are separated from the matrix by means of a liquid-solid extraction step which is followed by a coupled column HPLC procedure using an enriching precolumn consisting of silica modified with copper phthalocyanine. This special precolumn selectively adsorbs PAHs with at least three condensed rings and thus separates them from the urine matrix. The quantitative analysis was carried out using a switchable fluorescence detector. The detection limits were 6 ng/l urine (3-hydroxybenzo[a]pyrene) and 8 ng/l urine (3-hydroxybenz[a]anthracene). The relative standard deviations of the within-series imprecision ranged between 4.0% and 9.0%. The between-day imprecision was 7.7% (3-hydroxybenz[a]anthracene) and 12.9% (3-hydroxybenzo[a]pyrene). The recovery rates ranged between 102% and 124%. Using this analytical method we determined PAH metabolites in post shift urine samples from 19 workers engaged in the production of fire-proof materials. The urinary concentrations ranged from 3 to 198 ng 3-hydroxybenzo[a]pyrene per g creatinine and from 15 to 1871 ng 3-hydroxybenz[a]anthracene per g creatinine.

Occupational exposure to polycyclic aromatic hydrocarbons in a graphite-electrode producing plant: biological monitoring of 1-hydroxypyrene and monohydroxylated metabolites of phenanthrene.

OBJECTIVE: The objective of this study was to assess external and internal exposure to polycyclic aromatic hydrocarbons (PAHs) of workers who are employed in a graphite-electrode producing plant. Additionally we wanted to contribute to the question of biological limit values in order to reduce exposure to tolerable levels. METHODS: At five different working places 12 stationary and 16 personal air measurements were carried out to determine the concentrations of phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene and dibenz[a, h]anthracene in air. In addition, we investigated the excretion of 1-, 2 + 9-, 3- and 4-hydroxyphenanthrene and of 1-hydroxypyrene in the urine of 67 workers by a very sensitive and practical high-performance liquid chromatographic (HPLC) method with fluorescence detection; 2- and 9-hydroxyphenanthrene could not be separated with our analytical method. RESULTS: During the production of graphite electrodes significantly higher PAH exposures were found in the baking and impregnation area than in the crushing, graphitisation and conditioning area. The results of personal air measurements (mean values of the sum of eight PAHs) are: 29.3 (baking), 23.4 (impregnation), 5.2 (crushing), 1.3 (graphitisation) and 0.4 microgram/m3 (conditioning). Stationary air measurements yielded similar concentrations. Workers employed in the baking and impregnation areas excreted the highest amount of PAH metabolites in urine. The 1-hydroxypyrene concentrations (median) were: 23.4 (baking), 22.0 (impregnation), 9.6 (crushing), 1.8 (graphitisation) and 2.3 micrograms/g creatinine (conditioning). The corresponding concentrations of the sum of monohydroxylated phenanthrene metabolites (median) were: 23.1, 36.0, 10.4, 4.6 and 7.6 micrograms/g creatinine. Within the monohydroxylated phenanthrene metabolites 3-hydroxyphenanthrene predominates with a percentage of 43%. Our results showed that a benzo[a]pyrene concentration in air of 2 micrograms/m3 would lead to 1-hydroxypyrene concentrations in urine of 20-74 micrograms/g creatinine. That means that corresponding values in the literature which lie between 4.4 and 6.2 micrograms/g creatinine are due to other conditions of exposure and cannot be applied to graphite-electrode producing plants. CONCLUSIONS: Although to date there are no obligatory biological exposure limits for metabolites of PAHs in urine, it must be concluded that the internal PAH exposure is too high at some work places in this plant, as is generally the case in graphite-electrode producing plants. This is probably caused by skin absorption of PAHs. So for the prevention of health hazards by PAH, internal exposure must be measured using biological monitoring. Although it has not been possible to establish biological exposure limits for PAHs until now, we suggest a reduction in skin contact with these substances and thereafter use of the 90th percentile of the results of biological monitoring as "action levels" for corrective measures.

Protein degradability, amino acid composition, trypsin inhibitor and urease activity of raw and heat-treated fullfat soybean.

The effects of different heat treatments were studied on chemical composition, protein degradability, amino acid composition, trypsin inhibition and urease activity. Three lactating Holstein cows fitted with rumen cannulae were used. Fullfat soybean was prepared employing different forms of heat treatment: dry-extrusion at 150 degrees C for 25 s (treatment I); wet-extrusion at 95 degrees C for 30 min (treatment II); toasted soybean at 105 degrees C for 30 min (treatment III) extracted soybean meal (treatment IV); and untreated soybean (treatment V). The incubation times were 0, 2, 4, 8, 16, 24 and 48 h. Samples of raw and heat-treated soybean before incubation and the undegraded fraction after 4 and 16 h of incubation were analyzed for amino acids. The results showed that heat treatments did not modify chemical composition, but significantly reduced the content of trypsin inhibition and urease activity, as well as decreased protein degradability. The dry extrusion technique was comparatively the most effective. Amino acid content was not significantly influenced by different techniques, but the quantity of amino acids escaping degradation in the rumen increased.

Comparison of fullfat soybean, sunflower seed and protected fat as fat supplements for their effect on the performance of growing-finishing bulls and carcass fatty acid composition.

One hundred and twelve Holstein bulls (179-203 kg) were allotted to four dietary treatment groups (I: control; II: fullfat soybean diet; III: sunflower seed diet, and IV: protected fat diet) and used in a 120-day comparative feedlot trial to evaluate the effect of toasted fullfat soybean, whole sunflower seed and protected fat (calcium soap) on their weight gain, feed conversion and carcass fatty acid composition. The diets consisted of 45-46% concentrate and 55-54% corn silage. Digestibility, nutritive value as well as degradability were also determined. The apparent digestibility of dry matter, organic matter, N-free extract and crude protein as well as nutritive value were almost similar for the four diets. However, crude fibre, acid detergent fibre (ADF) and neutral detergent fibre (NDF) digestibilities decreased with increasing fat level but the differences were not significant. The inclusion of fullfat soybean or whole sunflower seed significantly (P < 0.05) increased the digestion of fat. Ruminal degradability of protein and dry matter were significantly (P < 0.01) lower for toasted fullfat soybean mixture compared to whole sunflower mixture. The inclusion of toasted fullfat soybean, whole sunflower seed and calcium soap in the diets was not effective in improving the bulls' weight gain or feed conversion in this trial. As both toasted fullfat soybean and whole sunflower seed increased the proportions of C18:1, C18:2 and C18:3 in adipose fat tissue and decreased the proportion of C16:0, they consequently significantly (P < 0.01) increased the ratio of unsaturated fatty acids. Whole sunflower seed was more effective than fullfat soybean. However, inclusion of the calcium soap had no effect on the fatty acid profiles in the present study.

Biological monitoring and biochemical effect monitoring of exposure to polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous carcinogenic substances to which man is exposed in the environment and at certain workplaces. Estimation of the resulting health risk is therefore of great occupational-medical and environmental-medical importance. Determination of the DNA and protein adducts of PAHs is the most suitable way of estimating this risk. The analytical methods used thus far, above all, 32P postlabeling, immunoassays, and synchronous fluorescence spectroscopy, are, however, too nonspecific; therefore, the results lack accuracy and are not comparable with one another. Only the use of very specific methods of instrumental analysis [above all, high-performance liquid chromatography (HPLC) and gas chromatography/ mass spectrometry (GC/MS)] can counteract this deficit. However, these methods can successfully be used mainly to determine the protein adducts of PAHs. Hemoglobin adducts, for example, do not have repair mechanisms like DNA adducts. They therefore occur in higher concentrations and can thus be analytically detected more easily. At present, mainly the monohydroxylated metabolites of PAHs are being determined in urine with great success. Using specific enrichment methods and HPLC with fluorescence detection it is even possible today to determine the internal PAH exposure of the general population. The detection limits lie in the lower nanogram-per-liter range. In view of the importance of this group of substances, determination of PAH adducts and the detection of their metabolites in urine will remain at the center of future occupational-medical and environmental-medical/toxicological research. In general, the lack of reference substances must be lamented.

Urinary levels of 1-hydroxypyrene, 1-, 2-, 3-, and 4-hydroxyphenanthrene in females living in an industrial area of Germany.

The concentrations of 1-hydroxypyrene (1-HOPYR), and 1-, 2-, 3-, and 4-hydroxyphenanthrene (HOPHE) as metabolites of pyrene and phenanthrene, were measured in urine samples collected from 124 housewives (27 smokers and 97 non-smokers) living in Bottrop, an industrial city located in the Ruhr area in Germany. The urine samples were analyzed by a very sensitive and practical high-performance liquid chromatographic (HPLC) method using a two-column switching technique and a special precolumn packing material followed by fluorescence detection. The polycyclic aromatic hydrocarbon (PAH) metabolites are selectively enrichéd on the precolumn and separated from the matrix. Therefore, laborious clean-up steps were omitted. The above-mentioned PAH metabolites could be detected in all urine samples investigated. Smokers had significantly higher urine concentrations of 1-HOPYR (median 0.48 microgram/g creatinine), 3-HOPHE (median 0.61 microgram/g creatinine), 2-HOPHE (0.41 microgram/g creatinine) and 4-HOPHE (median 0.10 microgram/g creatinine) than non-smokers (median 0.15 microgram/g creatinine, 0.31 microgram/g creatinine, 0.31 microgram/g creatinine and 0.04 microgram/g creatinine, respectively). The study shows that the influence of smoking is of such an order of magnitude that potential environmental exposure to PAH in this highly industrialized area is obscured by smoking habits. Furthermore, it can be concluded that the determination of 1-HOPYR, 1-, 2-, 3-, and 4-HOPHE in urine is a diagnostically useful method for the biological monitoring of persons environmentally exposed to PAH.

Biomonitoring and occupational medicine. Possibilities and limitations.

In the prevention of occupational diseases, biological monitoring has become very important. Today the individual level of exposure to many toxic substances can be assessed by routinely monitoring their concentrations in blood and urine. The adoption of effective quality control procedures allows reliable analytical results down to the ppt range to be obtained. Limit values such as the biological tolerance values for occupational exposure (BAT) from the Deutsche Forschungsgemeinschaft in Germany and the biological exposure indices (BEI) from the US American Conference of Governmental Industrial Hygienists (ACGIH) help to interpret the analytical results of biological monitoring. In spite of numerous advancements there are some gaps in the field of biological monitoring. Some groups of substances, such as pesticides, are still beyond the possibilities of biological monitoring. With regard to biological and biochemical effect monitoring, large gaps have to be filled and considerable research is needed. The number of limit values evaluated till now is still too small. Politics, however, seems to be the most serious limitation for biological monitoring.

Outward Currents in Rat Entorhinal Cortex Stellate Cells Studied with Conventional and Perforated Patch Recordings.

We have studied outward currents of neurons acutely isolated from superficial layers of the entorhinal cortex with whole-cell patch-clamp recordings. If cells were held more negative than -50 mV, depolarizing voltage commands activated a transient A-type current together with a sustained outward current. Both currents were sensitive to 4-aminopyridine, while only the sustained current was blocked by tetraethylammonium. The sustained outward current showed a considerable rundown in amplitude over prolonged recording periods. At the same time its half-maximal inactivation shifted from -74 to -114 mV. Nystatin perforated patch recordings were used to minimize these perfusion effects. Under such conditions the amplitude and the steady-state inactivation properties of the sustained outward current remained stable for more than 1 h. Pharmacological investigations revealed that only a small part of the sustained outward current could be attributed to a calcium-activated potassium current. Therefore most of the rundown has to be due to changes in the delayed rectifier outward current. These results may suggest that the delayed rectifier current is under considerable metabolic control.

Proteolytic enzymes do not destroy the N-methyl-D-aspartate (NMDA) sensitivity of acutely isolated hippocampal CA1 and CA3 neurons from postnatal rats.

Using whole cell recordings in combination with the concentration clamp technique it was shown that even enzymatically isolated hippocampal CA1 and CA3 neurons exhibit N-methyl-D-aspartate (NMDA) and L-aspartate currents. These currents were completely blocked by 0.5 mM Mg2+ or partially blocked (72.7 +/- 2.4%) by DL-2-amino-5-phosphonovalerate (50 microM) whereas 10 microM glycine (Gly) potentiated the NMDA responses (3.1 +/- 1.6-fold). A half-maximum dose of 55 microM was calculated from the sigmoid NMDA dose-response curve in the presence of 10 microM Gly. The amplitudes of these currents did not depend on the type of the proteolytic enzyme used for cell isolation.

Properties of the fast sodium channels in pyramidal neurones isolated from the CA1 and CA3 areas of the hippocampus of postnatal rats.

The fast sodium (Na)current of hippocampal neurones was recorded using the intracellular perfusion method. Neurones were isolated from the CA1 and CA3 hippocampal subregions separately, after treatment of the tissue with trypsin. There were no differences between the current-voltage (I-V) characteristics of CA1 and CA3 neurones. In contrast to this, the steady-state inactivation (h infinity) of both types of neurones was significantly different. Additionally, there were two subpopulations of CA1 neurones, which showed different courses of h infinity. Compared with CA1 neurones, the steady-state activation and inactivation curves of CA3 neurones overlapped much more in the potential range -80 mV to -50 mV. These results are consistent with the well-known fact that CA3 neurones show spontaneous burst activity, while CA1 cells do not. The time constant of activation (tau m) depended upon the membrane potential in the same way for all CA3 neurones investigated. However, there were two different subpopulations of CA3 cells, showing different voltage dependence of the time constant of inactivation. We conclude that these differences reflect two types of pyramidal cells within the same subregion.

Different ionic current patterns of acutely isolated neurons from the terminal ganglion of the cockroach Periplaneta americana L.

Ionic currents of somata, acutely isolated from the terminal ganglion of the cockroach Periplaneta americana, were investigated by the intracellular perfusion technique. By the ratios of the amplitudes of the fast inward current to the stationary outward current all isolated neurons are classified into three groups. State 1 neurons are characterized by a large amplitude of the fast Na current. At its maximum (-20 mV) the stationary outward current is small. In state 3 neurons, an inward current could not be observed at any potential, but the stationary component of the outward current at -20 mV is already large. State 2 neurons represent an intermediate type. In state 3 neurons, no fast Na current could be observed even after elimination of the outward currents electrochemically (substitution of K ions by Tris ions) or pharmacologically (application of 2 mmol/l 4-aminopyridine and 50 mmol/l TEA-Cl). Instead of this, a Ca current was recorded although fluoride was used as the intracellular anion.

Investigations of excitability of isolated and non-isolated neurons from the terminal ganglion of Periplaneta americana by current/voltage clamp and intracellular perfusion.

It was shown by means of current and voltage clamp measurements in combination with the intracellular perfusion method that the isolated motoneuron nerve cell bodies of the cockroach Periplaneta americana show overshoot action potentials. A regenerative Na current was found to be responsible for the excitability of these membranes; however, the results are not in agreement with a de novo synthesis of these channels.

A simple procedure for the isolation of neurons from the CA1 and CA3 region of the postnatal rat hippocampus.

A procedure was developed for the isolation of pyramidal neurons from defined regions (CA1, CA3) of the postnatal rat hippocampus. By a quantitative approach the influence of various parameters (pO2,glucose, enzymes, temperature, buffers, [Ca++]0, mechanical isolation) was evaluated on number and state of viability of the isolated cells using the nigrosine exclusion test and considering the neurons' morphological features. Cell viability of disaggregated Ca1- and CA3-neurons was compared. These isolated neurons are well suited for whole-cell patch-clamp measurements as well as for pharmacological investigations.

[Joint research on the precise determination of the energy and protein requirements of fattening pigs. 6. The effect of various energy and protein levels on the performance and feed expenditure of fattening pigs]. / Gemeinschaftsuntersuchungen zur Präzisierung des Energie- und Proteinbedarfs für Mastschweine. 6. Mitteilung. Einfluss verschiedener Energie- und Proteinniveaus auf Leistung und Futteraufwand bei Mastschweinen.

Scientific feeding experiments with hybrid pigs of the type Hungahib in the fattening period between 30 and 100 kg were carried out with one repetition as part of a joint international experiment. Feed, nutrient and energy expenditure were tested on 3 levels of energy supply (100 : 85 : 70%) and 3 levels of protein supply (18 : 16 : 14%) in the fattening period between 30 and 60 kg and 16 : 14 : 12% in the fattening period between 60 and 100 kg). In addition to this, parallel metabolism experiments were carried out to determine the digestibility and the N-balance of the feed mixtures used. The cost of feeding was also taken into consideration. The best results with regard to the fattening performance and the minimising of feed cost were achieved with the following ration type: (Table: see text). The fattening performance with this ration type was 712 g average daily live weight gain in the range between 30 and 60 kg live weight in the 1st fattening experiment and 601 g in the 2nd fattening experiment. A classification of the expenditure values has been attempted in the 10th contribution to this series of publications dealing with the total results of the joint international experiment.

[Joint research on the precise determination of the energy and protein requirements of fattening pigs. 10. Comparative evaluation of the research for the precise determination of the energy and protein requirements of fattening pigs]. / Gemeinschaftsuntersuchungen zur Präzisierung des Energie- und Proteinbedarfs für Mastschweine. 10. Mitteilung. Vergleichende Auswertung der Untersuchungen zur Präzisierung des Energie- und Proteinbedarfs für Mastschweine.

Institutes from 5 CMEA countries took part in complementary joint investigations in order to ascertain the variance in energy and protein requirement and parameters of nutrient and energy metabolism with such fattening pigs as test animals as characterise the prospective breeding development in each of the countries and in order to establish the bases for the critical revision of the norms of energy and protein requirement for fattening pigs and, if necessary, their more precise determination. The most important conclusion drawn from the comparative assessment of the results presented in 9 articles is that due to wide variations in the energy and protein requirement values between the individual investigators as well as within the institutions themselves, norms of energy and protein requirement for fattening can only be adopted between countries when adequate investigations under the specific conditions of the individual countries justify this.