Ernst Pfeffer

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We studied the effects of increasing dietary concentrations of each of the following amino acids on growth, feed intake, feed conversion ratio and composition of gain in rainbow trout in six dose-response experiments: L-lysine, L-tryptophan, L-histidine, L-valine, L-leucine and L-isoleucine. Semipurified diets containing 20.1 MJ digestible energy/kg dry(More)
In order to study the localization and mechanisms of intestinal phosphate transport in sheep and goats, unidirectional inorganic phosphate (Pi) flux rates across isolated stripped epithelial tissues were measured in vitro by applying the Ussing-chamber technique. In the first experiment the tissues were obtained from animals which had been kept on an(More)
A balance study was performed in order to quantify the effect of continuously increased phosphorus (P) intake on faecal and urinary P excretion. The aim was to quantify the level of intake where regulatory P excretion becomes relevant for comparative digestibility measurements on P, and when the pig adapts its urinary P excretion to increased P intake.(More)
The course of inorganic-phosphate (Pi) concentrations in blood plasma and serum were determined in lactating ruminants when P intake was changed abruptly from adequate, during a control period, to very low in a period of P depletion, and back to adequate during a period of P repletion. In each of three trials, four or three goats and, in one trial, four(More)
Unidirectional flux rates of Ca2+ across gastrointestinal tissues from sheep and goats were measured in vitro by applying the Ussing-chamber technique. Except for the sheep duodenum, mucosal to serosal Ca2+ flux rates (J ms) exceeded respective flux rates in the opposite direction (J sm) in both species and in all segments of the intestinal tract. This(More)
Faecal losses of phosphorus (P) were determined in 66 growing pigs weighing between 30 and 70 kg on a semi-purified diet containing less than 1.3 g P/kg DM. Regression analysis showed that the coefficient of absorption of P from this diet was 82.5% and that inevitable faecal P excretion of pigs fed this diet was, on average, 5.9 mg/kg BW.d-1 with no(More)
Ruminants are known to be able to very effectively recycle urinary urea and reuse it as a source of N for ruminal microbes. It is presumed that urea recycling is accomplished by specialized urea transporters (UT) which are localized in the kidney. This could be especially important in times of increased N requirement, such as during growth or during reduced(More)
We studied the effect of increasing dietary concentrations of DL-methionine on growth, feed intake, feed conversion ratio and the composition of gain in rainbow trout. Twenty-four groups of 20 trout initially weighing 51 +/- 0.5 g/trout were fed semipurified diets containing 20.1 MJ digestible energy and either 3.0 or 5.8 g cystine/kg dry matter. At each(More)
We studied the effects of increasing dietary concentrations of either L-arginine or L-threonine on growth, feed intake, feed conversion ratio and composition of gain in rainbow trout. Semipurified diets containing 20.1 MJ digestible energy/kg dry matter, with wheat gluten and crystalline amino acids as sole sources of amino acids, were fed to rainbow trout(More)
40 fetuses taken from 10 litters on day 50, 60 fetuses taken from 15 litters on day 105 of the respective pregnancies and 6 newly born piglets taken from 3 litters were analyzed for dry matter, total N, amino acids, fat, energy and 5 major minerals. As compared to the amounts found at birth, on day 50 about 3 per cent of the Na and K and less than 2 per(More)