A mean selenium of .123 mg/kg dry wt was observed in 195 samples of agricultural soils, and a mean of .158 mg Se/kg dry wt in 304 samples of grassland soils collected at 354 sites in various regions of the Federal Republic of Germany. For grassland soil, a north/south gradient of Se concentrations was observed. In the industrialized regions of the North, higher Se levels were generally observed, the highest value of .652 mg Se/kg dry wt at a site in Northrhine-Westphalia. The mean selenium content of grass from the respective collection sites was .045 mg/kg dry wt in all regions of the FRG, a level insufficient for the maintenance of health of farm animals. The absence of a correlation between the soil- and grass-Se contents indicates that Se uptake by plants is not solely dependent on the presence of Se. Grass may be deficient in Se even if grown on Se-rich soils. Fixation of Se by acidic soils appears to be a major factor; the high Se levels in the soils of industrialized areas is not bioavailable. Based on these findings, it is concluded that locally produced feedstock must be supplemented with Se to prevent the outbreak of deficiency diseases in farm animals.

Three experiments were carried out with male broiler chickens reared from day- old to 6 weeks of age on semi-purified diets containing 10% fresh (Expt. 1 and 3) or oxidized (Expt. 2) re-esterified triglycerides with a fatty acid composition similar to that of soya bean oil containing increasing concentrations of either a mixture of d-alpha-, gamma-, delta-tocopherylacetate (d-tocopherols) of natural source or dl-alpha- tocopheryl acetate (dl-tocopherol). In Expt. 1 and 2 the mixture of d-tocopherols consisted of 35.7% d-alpha-, 45.3% d-gamma- and 19.0% d-delta-, while in Expt. 3 the distribution was 25.3% d-alpha-, 28.1% d-gamma- and 10.8% d-gamma- in 35.8% re-esterified triglycerides. The relative biopotency of d-alpha-: gamma-: delta-tocopherol was anticipated to be 100:25:1, whereas that of dl-alpha-tocopherol was 74% relative to d-alpha-tocopherol. The experiments demonstrate that the results obtained for the biological activity depend on the response parameters chosen. With respect to gain in weight, feed conversion, relative organ weight, packed cell volume (PCV), ELP (erythrocyte lipid peroxidation), plasma activities of glutamate-oxaloacetate-transaminase (GOT), creatine kinase (CK) and glutathione peroxidase (GSH-Px) and plasma Na+ concentration, the mixture of natural source tocopherols was identical to that of dl-alpha-tocopheryl acetate, although the concentration of alpha-tocopherol was only about one third of that of dl-alpha-tocopherol. Differences between natural source and synthetic tocopherols were expectedly observed with respect to plasma concentrations of alpha-, gamma-, delta-tocopherol. Differences between the two forms as to muscular dystrophy, in vitro haemolysis and potassium concentration in plasma were ambiguous. It is suggested that the function of d-alpha-, gamma-, delta-tocopherol in erythrocyte fragility and skeletal muscle structure should be compared to that of dl-alpha-tocopherol in future investigations.

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Die Tiere der Gruppen I und IV (ohne Rapsolzulage) erbrachten 10.3 % Linolsaure und 1.6 % Linolensaure. Der knapp fiinfwochige Abstand der Gruppe I1 von der Rapsolzulage bis zur Schlachtung hat die Polyensaurengehalte nicht verandert. Z u s a m m e n f a s s u n g Im dreiphasigen Mastversuch mit schweren Schweinen (166 kg End-Lebendmasse) wurde keine nennenswerte Reduzierung der Linolsaurewerte im wichtigsten Fettkompartiment Ruckenfett durch Absetzen der Zulage des Futters mit sehr hohem Polyensaurengehalt (5.5 kg RapsSI/Schwein) iiber 111 bzw. 78 Tage vor dem Schlachten erreicht. Dieselbe Aussage trifft auch fur die am Ende der Mittelmast geschlachteten Tiere zu (35tagiger Abstand). Fur den Linolensauregehalt zeigte sich bei den schweren Schweinen eine signifikante Abstufung in Abhangigkeit von der zusatzfreien Mastdauer. Im NierenBeckenhohlen-Fett konnte die zeitliche Differenzierung signifikant ermittelt werden. D e r Rapsolzusatz hatte beim erwunschten, relativ starken Fettansatz der Schweine fur die Erzeugung der Qualitats-Dauerware verarbeitungstechnisch und sensorisch akzeptable Polyensaurenwerte in den Fettkompartimenten erbracht. L i t e r a t u r ' M . Kirchgessner. Tierernahrung, 7., neubearb. Auflage, DLG-Verlag, Frankfurt/Main, 1987. D. M . Vogg, Uber die Verteilung von Polyenfettsauren und a-Tocopherol in den Geweben des Schlachtkorpers von Mastschweinen, Dissertation ETH Zurich, Nr. 8876, 1989. C. Wenk und A. L. Prabucki, Faktoren der Qualitat von Schweinefleisch aus Schweizer Sicht, Aktuelle Themen der TierernYhrung und Veredelungswirtschaft, S. 53 -66, Lohmann Tierernahrung GmbH, Cuxhaven, 1990. C . Bee, Der Nahrstoffgehalt und das Fettsauretypenmuster des Gesamtkorpers von Mastschweinen unter Berucksichtigung der Futterung und der Wachstumsgeschwindigkeit,

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