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The quantification of faecal nitrogen (FN) and of urinary urea-N (UUN) and urinary non-urea-N (UNUN) excretion at varying N contents in ruminant rations is an important tool in assessing endogenous N turnover via the rumino-hepatic cycle. Using a statistical analysis based on an extensive database, the aim of this meta-analysis was to evaluate correlations derived previously by deduction. The data were categorised into dairy cattle, growing cattle (bulls and heifers), sheep and goats. Data from 50 publications were considered. The independent variable was the daily N intake (NI, g/day). The dependent variables were the daily quantities (g/day) of FN, urinary N (UN) , UUN, UNUN and N retention. The NI influenced FN to differing extents in goats, dairy cattle, growing cattle and sheep (listed in descending order of influence). Except in sheep, the effect was statistically significant. The influence on UN varied in the order goats, growing cattle, dairy cattle and sheep; the effect was statistically significant only for dairy cattle and growing cattle (P

The overall objective of this study was to calculate the amount of nitrogen (N) that cattle feed must contain in order to utilise the potential supply of utilisable crude protein at the duodenum provided by their energy intake without incurring a negative N balance, that is, without having to break down body protein. For this purpose, the literature was screened for measurements of net degradation and renal excretion of urea as well as N balances (N intake, faecal N and urinary N) in ruminants (cattle, sheep and goats) fed diets with varying N concentrations. Irreversible loss of N from the body urea pool increased with increasing N intake, but net degradation of urea as a proportion of irreversible loss decreased concurrently. Faecal N appeared not to be influenced by N intake and exceeded 11 g/kg dry matter intake (DMI) only in 7% of the data sets available. Urinary non-urea-N rarely exceeded 4 g/kg DMI and appeared independent of N intake. Urinary urea-N showed a clear dependence of N intake, and it is concluded that 1 g N/kg DMI is sufficient for compensating inevitable N losses in the form of urinary urea. In conclusion, ruminant rations should contain the following N concentrations (per kg DM) to account for obligatory losses: 11 g for compensating losses as faecal N, 4 g for compensating losses as urinary non-urea-N and 1 g for compensating inevitable losses as urinary urea-N. The derived recommendations should be helpful for limiting N excretion where this is desirable for ecological reasons.

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 dietary N intake. The aim of our study was to characterize and to localize UT in the goat (capra hircus) kidney and to investigate its response to reduced dietary N intake in growing goats. Therefore, 12 growing, male goats were fed either a diet containing high (17% CP in complete diet) or low (9% CP in complete diet) N content for 6 wk. After harvesting, blood and kidney samples were taken and analyzed. The mRNA of the different UT isoforms, UT-A1, UT-A2 and UT-B, were detected semiquantitatively in renal tissue by Northern blot analysis. For UT-A2 and UT-B, no statistically significant effect of dietary N restriction on renal mRNA expression could be detected (UT-A2: P = 0.26, UT-B: P = 0.07). However, renal mRNA abundance of UT-A1 significantly increased in the kidney of low-N-fed goats (P = 0.01). Furthermore, protein amounts of UT-B were verified by western blotting; and the localization of UT-A2 and UT-B protein was demonstrated by immunohistochemistry. No significant differences in protein amounts of UT-B could be observed comparing the 2 feeding groups (P = 0.78). The UT-B was localized in renal medulla and papilla, whereas UT-A2 was only found in renal medulla. In addition, comparison of UT-A and UT-BAA sequences of monogastric animals and ruminants showed a high degree of homology, indicating a similar function of the transporters among these species. In summary, we conclude that in ruminants, urea reabsorption in the kidney is most likely increased in response to a low-N diet via an upregulation of UT-A1 mRNA expression. Hypothetically, the reabsorbed urea can then be returned to the rumen via the bloodstream and thus be reused as a source of N for protein synthesis of ruminal microbial community.

Zusammenfassung Ratten erhielten Diaten mit Casein als alleinigem Proteintrager so zugeteilt, das die tagliche ME-Versorgung etwa 570 oder 750 kJ · kg-3/4 betrug. In je einer Gruppe mit niedriger bzw. hoher ME-Versorgung betrug die tagliche Rohprotein-Versorgung etwa 5 oder 10 g · kg-3/4. Zwei weitere Gruppen erhielten die hohe ME-Versorgung bei gleichen Rohproteingehalten im Futter wie bei niedriger ME-Versorgung. Nach einmaliger Futterung von 15N-markiertem Casein wurden aus den Bilanzdaten die Synthese und der Abbau von Korperprotein sowie die Oxidation freier Aminosauren berechnet. Erhohungen der Versorgung mit ME oder Rohprotein steigerten die Proteinsynthese, wahrend der Abbau von Korperprotein nicht derart deutlich beeinflust wurde. Die Oxidation freier Aminosauren wurde durch die Steigerung der ME-Versorgung gesenkt, durch die Steigerung der Proteinversorgung erhoht. Sofern fur die Proteinsynthese ein Teilwirkungsgrad von 0,87 angenommen wird, ist abzuleiten, das die bei der Proteinsynthese freiwerdende Warme zwischen 0,28 und 0,42 MJ je MJ retinierter Proteinenergie entspricht.

Zusammenfassung An 120 Mischfuttern und 16 Einzelkomponenten, fur die unter identischen Bedingungen die Verdaulichkeit in vivo ermittelt worden war, wurde die Genauigkeit der Schatzung des energe-tischen Futterwertes uberpruft, wenn einerseits die Weender Rohnahrstoffe einschlieslich Rohstarke und andererseits neben den Rohnahrstoffen die Gasbildung nach Inkubation mit Pansensaft als Kriterien zugrunde gelegt wurden. Die mittlere Abweichung des Schatzwertes von dem aus dem Verdaulichkeitsversuch errechneten energetischen Futterwert war bei Berucksichtigung der Gasbildung etwa halb so hoch wie bei Schatzung aufgrund der herkommlichen Analysendaten allein.

Zusammenfassung 14 Hammel erhielten in 14 Perioden je eine von 14 Rationen, die sich nur durch die Gehalte an Ca und P unterschieden. Die tagliche Aufnahme lag fur Ca zwischen 4 und 20 g und fur P zwischen 2 und 10 g. Nach einer zweiwochigen Angewohnungszeit wurde jeweils an 3 Tagen zu 3 bzw. 4 Zeitpunkten Blut und Speichel entnommen und auf beide Elemente untersucht. Die mehrfache Varianzanalyse ergab, das der Zeitpunk der Entnahme der Probe grosen Einflus auf den Phosphat-Gehalt in Serum und Speichel hatte. Futterungsbedingte Unterschiede sind nur fur vergleichbare Zeitpunkte cleutlich erkennbar. Keine Abhangigkeit von der Versorgung war fur die Ca-Gehalte im Speichel nachweisbar, wahrend sich im Serum eine negative Abhangigkeit von der Ca-Versorgung leicht und von der P-Versorgung deutlich zeigte. Die Phosphat-Gehalte waren parallel in beiden Flussigkeiten von der Ca-Versorgung deutlich und von der P-Versorgung sehr deutlich positiv beeinflust.

Zusammenfassung Einflusse von Labmagen-Infusionen von Casein auf die N-Ausscheidung und den Harnstoff-Umschlag bei Schafen Zwei Hammel erhielten taglich 500 g Stroh und 200 g Saccharose als Grundfutter. Durch eine Labmagenfistel wurden zwischen 0 und 150 g Casein infundiert. Die N-Ausscheidung im Kot war durch die Hohe der Infusion nicht zu beeinflussen. 68 bzw. 26% des als Casein infundierten N wurden unterhalb bzw. oberhalb des Bilanz-Ausgleichs retiniert. Der auf Harnstoff entfallende Anteil am gesamten Harn-N stieg von 37 auf 82%. Aus dem im Harn ausgeschiedenen Anteil einer einmaligen intravenosen Dosis von 14C-Harnstoff wurden Gesamtumschlag und Abbau im Verdauungstrakt fur Harnstoff berechnet. Beide Werte stiegen mit der infundierten Casein-Menge.

Zusammenfassung An 8 einzeln gehaltenen Aalen, die wahrend des Versuches ihre anfangliche Lebendmasse von etwa 175 g fast verdoppelten, wurde fur eine gereinigte Diat die Verdaulichkeit der Rohnahrstoffe ermittelt. Rohprotein aus Casein/Gelatine und Rohfett aus Sonneblumenol wurden fast vollstandig, NfE aus Maisquellstarke zu 85% verdaut. Aus der vergleichenden Ganzkorper-Analyse ergab sich, das der Zuwachs zu 42% aus Fett und zu 13% aus Rohprotein bestand. Etwa 60% der verdauten Energie fanden sich im Zuwachs wieder.

Zusammenfassung An intakten laktierenden Wiederkauern last sich die Synthese von Korperprotein berechnen, wenn neben N-Bilanzen nach einmaliger Dosierung von 15NH4Cl in den Pansen der Verbleib von 15N' in der Milch und im Korper gemessen wird. In 3 Versuchen mit 2 Ziegen betrug die Summe aus Produktion von Milchprotein und Synthese von Korperprotein taglich zwischen 1 und 3 g N/kg3/4. In keinem Fall war die Produktion von Milchprotein groser als die Synthese von Korperprotein. Die erhaltenen Ergebnisse fur Protein-Synthese liegen niedriger als Ergebnisse aus Untersuchungen mit markierten einzelnen Aminosauren.

Two balance experiments were carried out using lactating ruminants. In Experiment (Exp.) 1, seven goats per treatment were fed a constant roughage ration plus one of two concentrates, differing in their crude protein concentration. In Exp. 2, which followed a switch-over design, four dairy cows were fed a complete low-protein ration either with or without urea supplementation. According to official recommendations, N intake was either adequate or reduced by about 27 and 18% for goats and cows, respectively. Following a single intravenous dose of 15N-labelled urea, milk, faeces and urine were collected for periods of two weeks in Exp. 1 and of 10 days in Exp. 2. Lowering N intake caused reductions of milk urea concentration in both species but did not significantly affect intake, milk yield or milk protein concentration. In both experiments, lowering of N intake caused substantial reductions in excretion of urea in urine and milk but did not affect excretion of faecal N or urinary non-urea-N. N balances di...

Regulatory processes in phosphorus (P) homeostasis in small ruminants are quite different compared to monogastric animals. Adaptive responses of modulating hormones [parathyroid hormone (PTH) and calcitriol] to feeding variable amounts of P are lacking. Therefore, the aim of this study was to examine the influence of high dietary P intake (control diet: 4 g kg(-1) dry matter; high-P diet: 8 g kg(-1) dry matter) on the expression levels of PTH receptor (PTHR), vitamin D receptor (VDR) and Na+-dependent Pi transporters (NaPi II) in kidney and jejunum of goats starting rumination. After 3 months of feeding, plasma phosphate (Pi) and PTH concentrations were increased in the high-P diet group, whereas calcium and calcitriol were not changed. The intestinal Na+-dependent Pi transport capacity was not influenced by a high-P diet and the expression of jejunal VDR, PTHR and NaPi IIb was not modified. Interestingly, renal Na+-dependent Pi transport capacity was significantly reduced and concomitantly the expression of PTHR and NaPi IIa was decreased. In conclusion, the adaptive response of renal Pi reabsorption in goats, which were in transition from non-ruminant to ruminant stage was comparable to that of monogastric animals. In contrast, the modulation of the intestinal Pi absorption was like in adult ruminants.

P homeostasis affected by high or low Ca and/or P supply in preruminant goats was characterized by balance studies in vivo. The main excretion pathway was the renal P(i) excretion whose extent was modulated by variations in dietary P and/or Ca supply. Faecal P excretion remained low irrespective of dietary regimen. The balance data were combined with respective in vitro data on P(i) transport properties and their adaptation in response to changes in dietary Ca and/or P intake. Therefore, P(i) transport capacities were determined by P(i) uptake into brush border membrane vesicles of jejunum and kidney. Epithelial P(i) transporters were determined semiquantitatively by northern and western blot analyses in jejunum, kidney and salivary gland. Renal P(i) transport was downregulated by doubling dietary P supply while doubling both, Ca and P as well as restrictive Ca at unchanged P led to slight, but not significant reductions in renal P(i) transport. Jejunal P(i) transport was reduced by P excess (doubling P and doubling both, Ca and P), but only NaPi IIb protein expression was significantly diminished. In conclusion, the significance of epithelial adaptation to dietary Ca and P supply for P homeostasis is discussed in preruminant goats.

Retention time of food in the digestive tract is among the key variables that describe the digestive strategy of a herbivore. Mean retention time (MRT) was measured on 4 captive specimens of the okapi, a strictly browsing ruminant. Retention time was quantified on different diets, using Co-EDTA (fluid phase) and Cr-mordanted fibres (1-2 mm) (particle phase) as pulse-fed markers. Average food intake was 55-65 g DM/(kg BW0.75*d). Fecal excretion of the markers was quantified over 10 days. Different models to calculate retention time and passage rate in the gastrointestinal tract (GIT) and the reticulorumen (RR) were applied. Average MRT(particle)GIT was quantified to be 47+/-8 h and MRT(fluid)GIT 36+/-5 h. Concerning estimation of retention times in the reticulorumen, MRT(particle)RR was quantified to be 27+/-7 h, while MRT(fluid)RR was 17+/-4 h. The quotients MRT(particle)/MRT(fluid) were quantified to be 1.3+/-0.1 for the GIT and 1.6+/-0.2 for the RR. Compared to data established with comparable markers, the okapi has low coefficients of MRT(particle)/MRT(fluid). A less well developed retention mechanism for fibres compared to species like cattle or sheep can be explained by a comparatively high fermentation rate and low digestibility of the natural food of the okapi-browse-in comparison to grass.

It was the aim of this study to examine the potential regulatory effects of a long-term low dietary protein supply on the transport capacity of the jejunal brush-border membrane for amino acids. For this purpose, we used the neutral amino acids L-alanine (representative for nonessential amino acids) and L-leucine (representative for essential amino acids) as model substances. Ten sheep lambs, 8 weeks of age and 19-27 kg body weight, were allotted to two dietary regimes with either adequate or reduced protein supply which was achieved by 17.9% and 9.7% of crude protein in the concentrated feed, respectively. The feeding periods were 4-6 weeks in length. Similarly, eight goat kids of 5-7 weeks of age and 8-14 kg body weight were allotted to either adequate (crude protein 20.1%, feeding period 9-12 weeks) or reduced protein supply (10.1%, feeding period 17-18 weeks). Dietary protein reduction in lambs caused a significant body weight loss of 0.6 +/- 0.7 kg, whereas the body weight in control animals increased by 1.9 +/- 0.7 kg (P

The rapid development of precocial goats in the first weeks after birth requires an adequate adaptation of phosphate transport systems to maintain the P homeostasis at each developmental stage. Here we examined the age-related development of Na+-Pitransport systems in small intestines, kidneys, and parotid glands of goats. Kinetic parameters were determined by brush-border membrane vesicle uptake studies, and relative expression of NaPi type II mRNA and protein was recorded by molecular biological methods. High intestinal Pitransport capacity was already present on the first day of life. Within the first 3 wk of life there seemed to be a change in the type of Na+-dependent Pitransporter, and NaPi IIb was expressed increasingly up to the fifth month of life. Renal Na+-Pitransport capacity was also high at birth, and this was associated with high expression levels of NaPi IIa mRNA, indicating the important role of this transporter for renal Pireabsorption. At weaning an increase in both intestinal and renal Na+-Pitransport balanced the increasing requirements for Pito establish the endogenous Picycle. Salivary Piconcentration and parotid NaPi II mRNA rose markedly to guarantee an adequate Pisupply for rumen microbes. We concluded that the high demand for Piin young goats was assured by high basal Na+-Pitransport capacity of small intestines and kidney expressed continuously during ontogenesis.

It was investigated whether the availability and utilisation of free lysine are affected by crude protein concentration in rainbow trout diets. Wheat gluten and free amino acids were used as sole sources of amino acids to formulate two basal diets differing in crude protein (350 and 550 g/kg dry matter) but equal in lysine concentration (9 g/kg dry matter). Lysine was supplemented at the expense of l -alanine to achieve further lysine levels of 13 and 17 g/kg dry matter. l -lysine·HCl was used as the supplemental lysine source at both crude protein levels. Diets were offered to three groups of 20 trout each over a period of 56 days. Amount of feed was restricted to about 16 g dry matter/kg BW daily in order to allow for an equal and complete intake in all groups. Trout had an initial body weight of 50 g/fish. Digestibility was determined using acid-insoluble ash as a marker. Faecal samples were collected via a sedimentation system attached to each tank. Retention was determined by comparative whole body analysis. Faecal lysine excretion was unaffected by lysine supplementation irrespective of dietary crude protein level. Hence, l -lysine·HCl can be regarded 100% available to trout. In spite of comparable levels of DE intake, growth and gain/feed ratio increased with lysine supplementation. In gained body mass, protein concentration was increased and lipid concentration was decreased with increasing lysine supplementation. Amino acid pattern of gained body protein was changed by lysine supplementation as well. Lysine utilisation, determined as Δretained/Δdigested×100, was 55% on the low and 71% on the high dietary crude protein levels, respectively. This difference was close to significance, as judged by comparative regression analysis ( P =0.11). Dose–response studies with a wider range in lysine concentration at different crude protein levels are necessary to identify the consequences regarding lysine allowances for practical type trout diets.

A basal diet, aiming at a low lysine concentration (9 g/kg DM), was formulated with wheat gluten as the sole source of protein. Lysine concentration was increased in two steps of approximately 4 g/kg DM each by use of either l -lysine·HCl or l -lysine sulphate. Each diet was fed at a restricted rate to three groups of 20 rainbow trout for 56 days. Faecal samples were collected via a sedimentation system and availability was determined using acid-insoluble ash as a marker. Retention was measured via comparative whole body analysis. Faecal lysine excretion was not affected by lysine supplementation. Body weight gain and gain/feed ratio, as well as the composition of body weight gain, were significantly affected by dietary lysine concentration but not by lysine source. The utilisation of supplemental lysine, calculated as Δretained/Δdigested×100, was, on average, 68% and was not significantly different between the two lysine sources ( P =0.62). It is concluded that both lysine sources are equally available to rainbow trout.

Partitioning of digestible energy for maintenance and growth was examined in fast growing rainbow trout via multiple regression analysis. Data from 292 groups of rainbow trout fed a large variety of different diets for which digestible energy intake can be assumed as the factor limiting growth were used in the analysis. Intake of digestible energy, energy retention and protein as well as lipid gain had been quantified for each group of trout. Multiple regression suggested that maintenance requirement for digestible energy was dependent on the 0.43 power of body weight in grams. Depending on growth rate, maintenance requirement contributed to between 10 and 30% of the total digestible energy requirement. The utilisation of digestible energy that was available for retention proved to be dependent on fat concentration in the diet. Effects of dietary crude protein concentration or water temperature on digestible energy utilisation could not be determined for this data set. Daily digestible energy requirement (kJ) could be best predicted by 1.31 BW0.43 (g)+retained energy (kJ/day)/[0.66 (1+0.000652 g fat/kg dry diet)]. Assuming a partial efficiency of DE utilisation above maintenance for fat retention of 0.9, a partial efficiency of DE above maintenance for protein retention of 0.54 was calculated. An inter-laboratory approach is suggested to obtain a wider range of experimental data and, therefore, to improve the suitability of models for general application.

The effect of body weight on P digestibility and on efficacy of supplemental Aspergillus niger phytase was studied in two experiments with young growing pigs. Excreta were collected quantitatively. All diets contained 2.0 g digestible P per kg dry matter at a maximum and renal P excretion never exceeded 15 mg/d. When dietary P mainly originated from monocalcium-phosphate, both P digestibility and Ca net absorption linearly increased by 3.6 and 5.6 percentage units, respectively, when BW increased from 15 to 35 kg. With a similar range in BW, P digestibility and Ca net absorption were unaffected by BW when P mainly originated from maize, barley and soybean meal. In both types of diet, crude protein digestibility increased with increasing body weight, whereas organic matter digestibility was effected by BW only in the diet containing maize, barley and soybean meal. Phytase (400 U/kg) almost doubled P digestibility when supplemented to a diet with P mainly originating from maize, soybean meal and barley. This effect of phytase supplementation was equal in pigs at 15.7 kg BW (33 vs. 55%) and at 39.1 kg BW (32 vs. 56%). Digestibility of any organic fraction was unaffected by supplemental phytase. With regard to on-farm conditions, it appears eligible from this results to apply digestibility coefficients for P determined in growing-finishing pigs for piglets as well.

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. Phosphorus intake of growing pigs was continuously increased on a daily basis starting at a marginal level and P excretion via faeces and urine was continuously followed for 92 days. Two semi-synthetic diets were prepared with different proportions of Na2HPO4 resulting in 2.4 (diet 1) and 6.3 (diet 2) g P/kg DM. Concentration of Ca was adapted to achieve a Ca supply approximately 3.1 fold the digestible P supply. Six castrated male crossbred pigs (31 kg BW) were kept individually in metabolism crates after they had undergone a 14 d P depletion period during which they were fed diet 1 solely. Pigs received 1.04kg of diet 1 per day throughout the experiment, and each day the amount of feed and P supplied to pigs from diet 2 was increased by 12 g and 69 mg, respectively. ME supply was approximately 2.4 fold maintenance and average daily BW gain of pigs during the entire experiment was 690 +/- 30 g. While intake increased linearly, faecal excretion of P and Ca increased non-linearly and could be best described by third order polynomial functions. The proportion of ingested P not excreted via faeces followed a quadratic type of curve with a maximum of 81% at 25 days on experiment and P intake of 4.0 g/d. Thereafter, the proportion decreased continuously. The digestibility of P from diet 2, determined by the slope ratio technique, was constant and not affected by P intake up to a P intake of 5 g/d. Renal P excretion did not exceed inevitable losses until day 60 and increased exponentially thereafter when body P reserves were restored. It is concluded, that an adaptation to surplus P supply occurred earlier on the intestinal than on the renal level. While faecal P excretion appeared regulated depending on the actual requirement for P retention, the regulation via urine depended on the P status of the pig. Once the renal P excretion of growing pigs exceeds a level of 25 mg/d, intake of digestible P cannot be regarded sufficiently low to measure P digestibility as a capacity of the feedstuff.

Of 41 male kids, 14 were killed immediately after birth (3·3 kg BW); the remainder were either fed on goat milk to satiation or weaned at 10 kg BW. After achieving 15·7 kg BW, weaned kids were fed on complete diets including either 20 or 40% straw. Milk-fed kids were slaughtered at 16·8 or 26·7 kg BW, weaned kids at 15·7 or 29–30 kg BW, respectively (at least four kids per treatment). Empty BW as a proportion of final live BW was 0·91±0·02 in milk-fed kids compared to 0·85±0·04 and 0·76±0·04 in kids given complete feeds including 20 or 40% straw, respectively. Empty BW of kids in the heaviest groups were c. 24 kg for milk-fed or weaned kids. Energy and crude protein contents per kg empty BW increased from 4·5 MJ and 158 g in newborn kids to 12·2 MJ and 163 g in milk-fed kids or 10·4 MJ and 194 g in weaned kids, respectively. No influence of the feeding system was found on mineral contents of empty BW. Ca, P and K remained constant at 12·6, 7·7 and 1·9 g/kg, Mg increased from 0·32 to 0·46 g/kg and Na decreased from 2·0 to 1·3 g/kg. Differences in composition of live BW gain are mainly caused by differences in gut-fill. Efficiency of utilization of ME for growth was c. 0·75 in milk-fed kids even at high BW, but only 0·31 in weaned kids. Proportions retained of dietary N, Ca, P, Mg, Na and K were highest in milk-fed kids between birth and 16·8 kg BW: 0·57, 0·88, 0·78, 0·40, 0·37 and 0·10, respectively. They were lowest in kids fed on complete feed including 40% straw from 15·7 to 30·3 kg BW: 0·25, 0·26, 0·32, 0·04, 0·11 and 0·04, respectively. Weaning seems to be of greater influence on composition of BW gain and efficiency of utilization than the increase in empty BW.

Five smaller (body weight: 227.9 +/- 23.7 kg) and large growing bulls (435.2 +/- 14.3 kg per animal) each were fed with rations rich (chopped wheat straw:concentrate = 1:1) or poor in roughage (straw: concentrate = 1:4). Animals were kept in balance cages; 20 days adaptation period were followed by 10 days collection period. Body weight of bulls did not significantly influence apparent digestibility of rations. digestibility of organic matter of fibre rich ration was significantly lower (66.8%) than those of concentrate rich ration (74.4%). Feeding and body weight did not significantly influence metabolic parameters of mineral status. The fecal P-excretion amounted to 0.94 and 1.08 g per kg DMI in bulls fed with rations rich and poor in roughage. No influence of body weight was measured. Feeding and body weight did not significantly influence fecal P-excretion per kg DOMI (between 1.44 and 1.58 g P/kg DOM). For calculation of P-requirements for growing cattle fecal P-excretion amounted to 1.0 or 1.5 g P/kg DM and DOMI, respectively.

Summary Two basal diets and blends of these with one of 34 single ingredients were fed to groups of four Beagles for 21 days. The consistency of faeces was scored on the last 4 days of each period and the faecal dry matter was determined. The digestibility of organic matter and energy in the diets was determined by use of chromium sesquioxide as marker. No close correlation was found between the consistency and dry matter concentration of the faecal samples. Although the influences of individual feed ingredients on the faecal consistency and on faecal dry matter were obvious, these could not be explained by the digestibility of the organic matter or by the concentration of digestible energy in these feeds. Zusammenfassung Verdaulichkeit der organischen Substanz und verdaulichen Energie in einzelnen Komponenten extrudierter Hundefutter und deren Einflus auf den Gehalt an Trockensubstanz und die Konsistenz des Hundekotes Zwei Grundmischungen, rein oder nach Verschneiden im Verhaltnis zwischen 80:20 bis 60:40 mit 34 Einzelfuttermitteln, wurden als Extrudat an Gruppen von jeweils vier Beagles uber 21 Tage gefuttert. An den letzten vier Tagen jeder Periode wurde jeweils die Konsistenz des Kotes nach dem Augenschein benotet, der Gehalt an Trockensubstanz wurde bestimmt. Die Verdaulichkeit der organischen Substanz und der Energie wurde indirekt mit Chromoxid als Marker bestimmt. Keine klare Korrelation wurde gefunden zwischen der Note fur Konsistenz und dem Gehalt des Kotes an Trockensubstanz. Obwohl Einflusse von Einzelfuttermitteln sowohl auf den Gehalt an Trockensubstanz als auch auf die Konsistenz des Kotes offenkundig waren, liesen diese sich nicht mit der Verdaulichkeit der organischen Substanz oder dem Gehalt an Verdaulicher Energie erklaren.

Summary Multiple regression analysis was carried out for the results of digestibility determinations carried out with dogs fed 45 different dry extruded foods in which proximate nutrients, detergent fibre and α-linked plus free glucose (a-Glc) had been analysed. The following formula for estimating the digestible energy (DE) was found to be the most accurate: Inclusion of detergent fibre did not improve the accuracy of estimation. Zusammenfassung Schatzung der Verdaulichen Energie in extrudiertem Trockenfutter fur Hunde Mittels multipler Regressionsanalyse wurden die Ergebnisse von Verdaulichkeitsbestimmungen mit Hunden ausgewertet, in denen 45 verschiedene extrudierte Trockenfutter untersucht worden waren. In den Futtern wurden neben den Weender Rohnahrstoffen noch NDF, ADF und alpha-glucosidisch gebundene plus freie Glucose (a-Glc) bestimmt. Folgende Schatzglcichung fur die Verdauliche Energie wurde als empfehlenswert abgeleitet: Hinzunahme von NDF oder ADF fuhrte nicht zu Verbesserungen der Schatzgenauigkeit.

Zusammenfassung Laktierende Milchziegen wurden uber 2 jeweils dreiwochige Perioden unterhalb ihres Nettobedarfes an P versorgt. Die Tiere erhielten eine Ration aus NaOH-aufgeschlossenem Stroh und Milchleistungsfutter (MLF), das entsprechend der Milchleistung zugeteilt wurde. In Periode 2 wurden dem MLF je kg T 1 g P aus Tricalciumphosphat (TCP) im Austausch gegen Futterkalk zugelegt. Wahrend der jeweils letzten 7 Tage jeder Periode wurde die P-Bilanz ermittelt. Zusatzlich wurde, beginnend 5 Tage vor der Umstellung, die Konzentration des anorganischen Phosphates (Pi) im Blutplasma der Tiere bestimmt. Die Tiere wiesen in beiden Versuchsperioden eine eindeutig negative P-Bilanz auf, so das die Voraussetzungen zur Bestimmung der Verwertbarkeit des P aus TCP gegeben waren. Die P-Ausscheidungen in Milch, Kot und Harn waren durch die Zulage von TCP nicht beeinflust. Allerdings waren der Futterverzehr wegen der geringeren Milchleistung in Periode 2 und damit auch die unvermeidliche P-Ausscheidung mit dem Kot deutlich geringer. P aus TCP wurde im Mittel zu 65 % verwertet. Die Konzentration von Pi im Blutplasma stieg im Velaufe der Periode 2 kontinuierlich von 0,2 auf 0,47 mmol/1. Summary Availability of phoshorus from tricalcium-phosphate to lactating goats During two periods of 3 weeks each, lactating goats were fed diets based on NaOH-treated straw and concentrates which did not cover their net requirements for phosphorus (P). Concentrates were supplied according to the individual milk yield. In the concentrate used in period 2, 1 g P/kg was supplied by tricalcium phosphate. Balance periods were performed during the last seven days of each period. Concentration of inorganic phosphate in blood plasma was determined. The P balance was negative in both period 1 and period 2. Therefore, the availability of P from tricalcium-phosphate can be calculated. Phosphorus excretions with milk, faeces and urine were not influenced by the supplementation of P in period 2. However, dry matter and, as a consequence, inevitable losses of P were lower in period 2 when compared with period 1. Availability of P from tricalcium-phosphate was 65 %. Concentration of inorganic phosphate increased continuously from 0.2–0.47 mmol/l during period 2.

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 measuredin vitroby applying the Ussing-chamber technique. In the first experiment the tissues were obtained from animals which had been kept on an adequate dietary P supply. In the second experiment the animals had either been kept on an adequate Ca and P supply or were Ca- and/or P-depleted. Significant net Piabsorption was measured in all segments of the small intestine and in the proximal colon of sheep and in the duodenum and jejunum of goats. Since the experiments were carried out in the absence of any electrochemical gradient, this clearly indicates the presence of active mechanisms for Pitransport in the intestinal tract of small ruminants. In sheep jejunum, reduction of mucosal Na concentration to 1·8 mM or serosal application of ouabain (0·1 mM) resulted in significant decreases of net F; absorption of the same order of magnitude, indicating that about 65% of active Pitransport in sheep jejunum is mediated by a Na-dependent active transport mechanism. The mechanism for the remaining Na+-independent active Pitransport has not yet been identified. Dietary P depletion caused hypophosphataemia and induced a significant stimulation of net Piabsorption in goat duodenum and jejunum. This increase was independent of dietary Ca supply and was not associated with increased plasma calcitriol concentrations. This suggests substantial differences in hormonal regulation of Pitransport in small ruminants in comparison with single-stomached species.

Zusammenfassung Wirkungen der Reduktion von Ca und/oder P im Futter wachsender Ziegenbocke In einem 2-faktoriellen Versuch erhielten je 5 Ziegenbocke einer anfanglichen Lebendmasse von 12,5 kg uber 63 Tage Konzentratmischungen, die je kg Trockenmasse 10,9 oder 3,9 g Ca und 4,6 oder 2,0 g P enthielten, im Verhaltnis 5:1 mit Gerstenstroh. Verzehr und Zunahmen wurden signifikant durch die Erniedrigung des P-Gehaltes, nicht jedoch des Ca-Gehaltes reduziert. Die Verdaulichkeit der Organischen Substanz wurde durch die Erniedrigung des P-Gehaltes vermindert. Die Ca-Versorgung hatte lediglich einen Einflus auf die Verdaulichkeit des Rohfettes, die bei niedriger Ca-Versorgung signifikant erhoht war. Obwohl der groste Anteil der Ausscheidung beider Elemente auf den Kot entfiel, waren signifikante Einflusse auf die Hohe der renalen Ausscheidung beider Elemente nachweisbar. Im Blutplasma wurde die Phosphat-Konzentration durch niedrige Ca-Aufnahme erhoht, durch niedrige P-Aufnahme ernie-drigt. Die Ca-Konzentration war bei niedriger P-Aufnahme signifikant erhoht. Ein signifikanter Einflus auf die Aktivitat der alkalischen Phosphatase bestand nicht. Ansatze von Ca, P und Mg im Leerkorper wurden durch niedrige Ca-Aufnahme erniedrigt. Bei niedriger P-Aufnahme fand kein Ansatz dieser Elemente statt, wenn auch die Ca-Aufnahme erniedrigt war, bei hoher Ca-Aufnahme traten sogar Verluste auf. Vergleichbare Effekte zeigten sich fur die isolierten Femora.

Effects of a supplemental Aspergillus niger-phytase on digestibility and utilization of dietary phosphorus (P) were studied in three experiments with rainbow trout. P concentration in the diets was 4.8 and 5.8 g/kg DM, respectively. The P contained in the diet originated solely from plants, mainly soy-products. Digestibility of P was studied using the stripping method and hydrochloride insoluble ash as marker. Utilization was studied in growth trials by use of the comparative body analysis. At a water temperature of 15 degrees C, both digestibility and utilization of P were increased from 25 to 57% and from 17 to 49%, respectively when 1000 U/kg phytase were supplemented. Feed consumption and gain of trout were significantly increased. At a water temperature of 10 degrees C, utilization of P was also increased from 6 to 25%. However, feed consumption and gain of trout were very low at this water temperature and not influenced by the supplemental phytase.

The binding capacity (Bmax) and the affinity (Kd) of the intestinal vitamin D receptor (VDR) have been studied using mucosa preparations from the duodenum, jejunum and proximal colon of male growing goats which had been kept in a two-factorial (2 x 2) trial on Ca and/or P deficient diets for 9 weeks. This treatment resulted in significant changes of different parameters of Ca and P homeostasis. Irrespective from the level of Ca intake, P depletion caused significant hypophosphatemia with corresponding hypercalcemia. In both Ca depleted groups the calcitriol concentrations in plasma significantly increased by more than 100% in comparison with normal Ca supply. No changes were recorded for plasma calcitriol concentrations in response to P depletion with an adequate Ca supply. Plasma PTH levels were only increased significantly in Ca depletion with adequate P supply. Irrespective of different feeding regimens, the highest Bmax values were found in the jejunum. In all intestinal segments tested, the Bmax values were significantly decreased by P depletion as compared with an adequate P supply. No effects on the Bmax of VDR were observed in response to changes of Ca supply. The Kd values of the VDR were neither affected by different intestinal localizations nor by Ca and/or P depletion. From the present results, it has to be concluded that the physiological relevance of VDR down-regulation may not be related to P homeostasis rather than to Ca homeostasis by minimizing the hypercalcemia induced by P depletion.

Zusammenfassung Phosphor- und Calcium-Bilanzen von Milchziegen wahrend Perioden einer Phosphor-Depletion und einer anschliesenden Phosphor-Repletion Nach Uberschreiten der Laktationsspitze wurden an Milchziegen Bilanzversuche durchgefuhrt. Nach einer Kontrollperiode mit normgerechter P-Versorgung erfolgte eine P-Depletion von vier (Versuch 1), acht (Versuch 2) und drei (Versuch 3) Ziegen durch Verabreichung von Futter mit sehr niedrigem P-Gehalt (

Zusammenfassung Anderungen der Korperzusammensetzung von Milchziegen durch eine Phosphor-Depletion Unmittelbar nach der Laktationsspitze wurden vier Ziegen als Kontrolltiere geschlachtet und vier Ziegen erhielten ein P-armes Futter. Nach dem Verlust von im Mittel 85 g P und 139 g Ca pro Tier wurden diese Ziegen ebenfalls geschlachtet. Die Leerkorper wurden in 11 Fraktionen zerlegt und analysiert. Im Anteil der einzelnen Korperfraktionen ergaben sich keine Anderungen mit Ausnahme der Euter. Die Gesamtfett-Gehalte blieben in allen Fraktionen unbeeinflust, bei den Rohprotein-Gehalten zeigten sich nur in den Lebern signifikante Erniedrigungen. Die Gehalte an Rohasche, P und Ca waren in Kopf und Skelett signifikant erniedrigt. Die P-Konzentrationen waren signifikant erniedrigt in Verdauungstrakt, Leber, Nieren und Milz, aber nicht beeinflust in Haut und Haar, Muskulatur, Herz, Lungen und Euter. Die im gesamten Leerkorper enthaltenen Mengen differierten zwischen beiden Gruppen im Mittel um 67 g P und 127 g Ca pro Ziege. Aus dem Vergleich der Ergebnisse des Bilanzversuchs und der Leerkorper-Analysen wird abgeleitet, das pro Ziege 18 g P und 12 g Ca aus Inhalt des Verdauungstrakts zu den Verlusten beigetragen haben mussen.

Four balance trials were performed, each using four growing pigs initially weighing about 30 kg. Trial 1 was subdivided into three periods: Period 1, 21 days; Period 2, 21 days; Period 3, 15 days. Phosphorus (P) concentration in dry matter (DM) of the pelleted diet was 2.27 g kg−1 in Periods 1 and 3, respectively, and 0.83 g kg−1 in Period 2. Adaptation of faecal P concentration after each change in dietary P concentration was completed within 7 days. Trials 2–4 followed the design of a Latin Square (4×4). A basal diet low in P concentration was fed either alone or after blending into test diets containing 60% of maize, wheat or triticale. Each basal and test diet was fed either unsupplemented or after addition of 750 units kg−1 of microbial phytase. All diets were fed unpelleted. Available P (determined as apparent digestible P) of each of the three grains was calculated from differences of results on test and corresponding basal diets. Supplemented microbial phytase increased P availability from 18% to 56% in maize, from 62% to 74% in wheat, and from 52% to 67% in triticale.

Summary 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 cows were used. In addition, the course of P concentration in the rumen fluid of three fistulated goats was studied. Pi concentrations in plasma or serum started to fall immediately with changing P intake from adequate to low, reaching a minimum plateau of less than 0.25 mM in three trials and 0.4 mM in one trial. Correspondingly, concentrations rose instantly with return of P intake to adequate, overshooting the range observed in goats during the control period and then returning to normal. P concentration in particle-free rumen fluid declined from about 30 mM in the control period to 5.7 mM during P depletion and returned to 30 mM during P repletion, paralleling the respective course of Pi in blood plasma.

Zusammenfassung Die Bestimmung der Verdaulichkeit des Phosphors (P) aus mineralischen Einzelkomponenten, Mineralfuttermitteln, Eiweiskonzentraten und Alleinfuttermitteln fur Schweine im Differenzversuch sollte uberpruft werden. Hierzu wurden vier Bilanzversuche mit je vier wachsenden Schweinen einer anfanglichen Lebendmasse von 30 kg durchgefuhrt. Die zu prufenden Futtermittel wurden in unterschiedlichen Anteilen einer Grundmischung zugelegt, die arm an P war. Die P-Gehalte aller Futtermischungen wurden so eingestellt, das durchgehend eine suboptimale Versorgung der Schweine mit P gegeben war. Die Verdaulichkeit des P wurde fur die Testmischungen und die Grundmischungen gemessen und fur die gepruften Futtermittel aus dem Unterschied berechnet. Die P-Verdaulichkeit war zwischen den untersuchten Futtermittelgruppen deutlich verschieden. Auch innerhalb einer Gruppe waren mit Ausnahme der Alleinfutter signifikante Unterschiede zwischen den gepruften Futtermitteln erkennbar. Fur Mono-Natrium-Phosphat, Mono-Calcium-Phosphat und Di-Calcium-Phosphat-Anhydrid wurden Verdaulichkeiten des P von 96 %, 91 % und 87 % ermittelt. Die Verdaulichkeit des P der untersuchten Mineralfutter und Eiweiskonzentrate lag zwischen 69 % und 83 % bzw. zwischen 63 % und 73 %. Die Verdaulichkeit des P aus den ausgewahlten Alleinfuttermitteln lag zwischen 54 % und 56 %.

Zusammenfassung Wirkungen niedriger P-Versorgung bei normalen und hohen Ca-Gehalten im Futter von Milchziegen auf Leistung und Mineralstoff-Bilanzen wahrend Trachtigkeit und Laktation An Milchziegen wurde ein 2-faktorieller Versuch (2 times 2) von der 7. Laktationswoche bis zur 6. Woche der folgenden Laktation durchgefuhrt. Fur 4 Tiere je Behandlung entsprach die P-Versorgung entweder den Empfehlungen des NRC (1981) oder sie war auf die Hohe des angenommenen Nettobedarfes reduziert, wahrend die Ca-Versorgung entweder normgerecht oder in doppelter Hohe erfolgte. Futterverzehr, Verlauf der Lebendmasse, Milchleistung, Fortpflanzung und Verdaulichkeit der organischen Substanz wurden nicht signifikant durch den Gehalt von P oder Ca im Futter beeinflust. Die Reduktion der P-Versorgung bewirkte im Blutplasma eine Senkung des Phosphat-Gehaltes und einen Anstieg des Calcium-Gehaltes, wahrend die Verdoppelung der Ca-Versorgung ohne Wirkung auf beide Werte blieb. P- und Ca-Bilanzen wurden in 7 Phasen des Versuches bestimmt. Zu Beginn verloren die Ziegen bei reduzierter P-Versorgung taglich 0,2–0,6 g P, spater unterschied sich die P-Bilanz dieser Tiere nicht von derjenigen der angemessen mit P versorgten Tiere. Die Hohe der Ca-Aufnahme hatte keinen Effekt auf die P-Bilanz. Die Ca-Bilanz wurde weder durch die Ca-Aufnahme noch durch die P-Aufnahme signifikant beeinflust.

Zusammenfassung Anderungen in der P- und der Ca-Bilanz sowie Verlauf der Gehalte an anorganischem Phosphat und Calcium im Blutplasma von Milchziegen nach Umstellung von reduzierter auf angemessene P-Versorgung bei normaler oder hoher Calcium-Aufnahme Nachdem acht Milchziegen ein Jahr lang eine reduzierte P-Versorgung erhalten hatten, die nur etwa den Netto-Bedarf deckte (rP), wurden sie auf eine nach NRC (1981) angemessene P-Versorgung umgestellt. Je vier Ziegen erhielten durchgehend eine Ca-Versorgung, die nach NRC angemessen war (aCa) oder etwa die doppelte Menge (hCa). Eine Woche vor der Umstellung und in den Wochen 1, 2, 5 und 6 danach wurden Kot und Harn quantitativ gesammelt. In regelmasigen Abstanden wurden Blutproben entnommen. Signifikante Einflusse der Ca-Versorgung ergaben sich weder auf die Gehalte an Phosphat und Calcium im Blutplasma noch auf die P- und Ca-Bilanzen. Nach dem Umstellen der P-Versorgung stieg die Phosphat-Konzentration im Blutplasma in wenigen Tagen von unter 0,5 auf uber 2,0 mMol je Liter. Vor der Umstellung verloren die Tiere P, wahrend ihre Ca-Bilanzen nicht signifikant von 0 abwichen. In den auf die Umstellung folgenden 2 Wochen lagerten sie taglich im Mittel 1,7 g P und 2,0 g Ca ein, in den Wochen 5 und 6 nach der Umstellung waren es im Mittel 0,6 g P und 1,4 g Ca.

Zusammenfassung Einflus von zweierlei P-Aufnahme auf Leistungen und P-Ausscheidung im Kot von Milchkuhen Zwei Gruppen von je 26 Milchkuhen erhielten als Grundration Grassilage und Maissilage und dazu Milchleistungsfutter nach Leistung. In der einen Gruppe erhielt jede Kuh taglich 6 g P mit dem Mineralfutter, wahrend das Milchleistungsfutter 4.3 g P/kg T enthielt. In der anderen Gruppe war Phosphat weder dem Mineralfutter noch dem Milchleistungsfutter zugesetzt, welches deshalb nur 3,6 g P/kg T enthielt. Im Mittel betrug die P-aufnahme 68 bzw. 60 g je Kuh und Tag. Keine Unterschiede in Leistung, Gesundheit und Fruchtbarkeit wurden wahrend des zwei Jahre dauernden Versuches beobachtet bei durchschnittlich 7500 kg Milch je Kuh und Jahr. Nahe der Laktationsspitze wurde bei 10 Kuhen jeder Gruppe die Kotmenge indirekt bestimmt mittels Chromoxid als Marker. Der Unterschied in der P-Aufnahme in Hohe von 13 g/Tag spiegelte sich in einem entsprechenden Unterschied in der P-Ausscheidung mit dem Kot wider. Offenbar war ein Ausgleich der P-Bilanz auch in diesem Stadium moglich. Es wird die Schlusfolgerung gezogen, das bei Milchleistungen von 7500 kg je Kuh und Jahr Phosphat-Zulagen weder zum Mineralfutter noch zum Milchleistungsfutter erforderlich sind, sofern ein nativer P-Gehalt in der Gesamtration von 3.3 g je kg Trockensubstanz nicht unterschritten wird.

Zusammenfassung Einflus der Futteraufnahme auf die Phosphor-Verluste im Kot von Milchkuhen bei Futterung von Rationen mil niedrigem Phosphorgehalt An zweimal funf Milchkuhe gleicher mittlerer Lebendmasse, die sich jedoch in der Hohe ihrer Milchleistung unterschieden, wurden der Leistung entsprechend pro Kuh und Tag 16,9 kg (Gruppe I) und 10,9 kg (Gruppe II) Trockenmasse einer Ration gleicher Zusammensetzung gefuttert. Die tagliche Phosphor-Aufnahme je Kuh betrug 37,0 g in Gruppe I und 21,5 g in Gruppe II. Zwischen beiden Gruppen zeigten sich keine Unterschiede in den Verdaulichkeiten der Rohnahrstoffe und im Gehalt an anorganischem Phosphat im Blutserum. In der neuntagigen Sammelperiode ergab sich fur die Gruppen I und II mit – 1,6 g und – 0,8 g eine nicht signifikant von 0 unterschiedliche “P-Bilanz”. Die Ausscheidung im Kot betrug fur beide Gruppen 1,2 g P je kg aufgenommener Trockenmasse. Aus den Ergebnissen wird geschlossen, das die unvermeidlichen P-Verluste im Kot von der Hohe der Trockensubstanzaufnahme abhangen und folglich in der faktoriellen Bedarfsableitung darauf bezogen werden sollten.

Zusammenfassung Weizen und Weizenstarke als mogliche Quellen von verdaulicher Energie fur Regenbogenforellen (Onkorhynchus mykiss) An Regenbogenforellen wurden acht Futtermischungen gefuttert, in denen entweder zu 25 oder zu 45% eine der folgenden Komponenten enthalten war: unbehandelter Weizen, hydrothermisch behandelter Weizen, rohe Weizenstarke, Weizenquellstarke. Der Gehalt an verdaulicher Energie (DE) in den ubrigen verwendeten Mischungskomponenten (Casein, Weizenkleber, Fischol) war aus vorangegangenen Untersuchungen bekannt. Die Summe aus zu testender Komponente und Casein machte in jeder Mischung 75% aus. Jeder Mischung war Cr2O5 als inerter Marker zugesetzt. Kot wurde durch Abstreifen gewonnen. Fur jede zu testende Komponente war der DE-Gehalt bei einem Mischungsanteil von 45% niedriger als bei 25%. Ausgedruckt als Funktion des Mischungsanteils L ergab sich fur die einzelnen Komponenten folgender Gehalt an DE (MJ/kg Trockensubstanz): 22.8 – 0.36 L fur unbehandelten Weizen; 22 2 – 0.20 L fur hydrothermisch behandelten Weizen; 8.9 – 0.08 L fur rohe Weizenstarke; 18.5 – 0.20 L fur Weizenquellstarke. Die Verdaulichkeit des Rohproteins war fur alle Mischungen mindestens 96% und zeigte keine negative Beeinflussung durch Steigerung des Proteingehaltes der Mischung.

Zusammenfassung Untersuchungen zum Lysinbedarf von Regenbogenforellen (Oncorhynchus mykiss) bei Weizenkleber als alleinigem Futterprotein Es wird uber drei Futterungsversuche mit Regenbogenforellen berichtet. Im ersten Versuch wurde der Fischmehl-Anteil einer Kontrollmischung durch Weizenkleber und Fischol ersetzt. Die hierdurch bewirkte Leistungsdepression wurde nahezu vollig aufgehoben, wenn dem Futter L-Lysin · HCl zugesetzt wurde. Im zweiten Versuch erfolgte in 8 Schritten eine Steigerung der Lysin-Erganzung bei Weizenkleber als alleiniger Proteinquelle. Maximale Aufnahmen und Zuwachsraten wurden erzielt, wenn der Lysingehalt im Futter 1,0 g je MJ verdauliche Energie uberstieg, hochste Verwertung des Lysins mit 74% bei 0,89 g Lysin/MJ DE. Im dritten Versuch wurde festgestellt, das die Erhohung des Lysingehalts von 1,3 auf 1,6 g je MJ DE zu Erniedrigungen bei Verzehr und Zuwachs fuhrte und das andererseits auf beiden Stufen die Zulage von Arginin und/oder Threonin keinen Einflus auf Verzehr, Zuwachs oder Zusammensetzung des Zuwachses hatte, obwohl ohne Zulage die Verwertung dieser beiden Aminosauren hoher als 60% war.

(1991). Hydrothermically treated soy beans as source of dietary protein for rainbow trout (Salmo gairdneri, R.). Archiv fur Tierernaehrung: Vol. 41, No. 2, pp. 223-228.

A trial with 90 cows was conducted to examine the effect of supplementing 30 g N-hydroxymethyl-DL-methionine-calcium (HMM-Ca) from 14 days pre calving till 100 days in lactation on the performance and some physiological traits. Cows were kept on four energy levels by feeding different amounts of concentrate. At each energy level, half of the cows were given a methionine supplement. Forage consisted of 1/3 corn- and/or beet pulp silage and 2/3 grass silage ad libitum. The amount of daily milk yield differed not significantly from 31.5 kg for the supplement group to 30.6 kg for the control group. No interaction between the methionine supplementation and energy level could be detected. Mean methionine content in blood plasma differed from 22.7 mmol/l for the supplement group to 16.8 mmol/l for the control group. GOT, tau-GT, bilirubin and urea in blood serum and milk urea content did not indicate a positive effect of the methionine supplementation on the metabolism. Conception rate differed slightly from 87% in the supplement group to 73% in the control group.