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The amount of crude protein entering the small intestine (nXP) and the nitrogen balance in the rumen (RNB) are the two components of the German protein evaluation system. Although there is no scientific evidence, feeding strategies for the practice imply an excess in RNB, particularly in diets for high-yielding cows. This study was undertaken to investigate whether cows benefit from an excess in RNB under conditions of sufficient nXP supply. Three rations were used equal in energy (7.2 MJ net energy for lactation per kilogram dry matter; DM) and nXP (173 g/kg DM) and mainly based on silages from maize, grass, and brewer's grains as well as ground barley and solvent extracted meals from rapeseed and soybeans. Three rations were calculated to allow for an RNB of either 0 or 50 g/day. RNB was adjusted by either a supplementation of urea or a change in the proportions of oilseed meals. The intended levels of energy, nXP and RNB in the diets were confirmed under consideration of separate digestibility measurements with wether sheep and a chemical fractionation of dietary crude protein. The rations were offered as total mixed rations. At least 35 cows between days 21 and 98 of lactation were used per treatment. Cows were milked three times daily and had continuous access to feed and water. Feed intake was measured continuously and for each cow individually by a feeder system through which the rations were offered. The average values for the three treatments ranged between 20.1 and 21.7 kg/day for DM intake, 43.0 and 44.0 kg/day for milk yield, and 1.39 and 1.42 kg/day for milk protein yield. No significant treatment effect was detected in any of the monitored criteria. Cows were in a negative energy budget as indicated by a loss in backfat thickness, similar for all treatments. Under inclusion of literature data it is concluded that under conditions of a sufficient nXP supply, dairy cows do not need an excess in RNB in total mixed rations, even at very high levels of milk protein yield.

Influence of alimentary zinc deficiency on nitrogen elimination and activities of urea cycle enzymes This study was conducted to investigate whether the hyperammonaemia shown in earlier zinc-deficiency experiments was the result of disturbed enzyme activities of the urea cycle. For this study 36 male Sprague-Dawley rats with an average body weight of 85 g were divided into three experimental groups of 12 animals each. Group 1 received the semisynthetic zinc-deficient diet (AIN-93G; 1.2 mg Zn/kg DM) ad libitum over 33 experimental days. Group 2 received the zinc-sulphate-supplemented control diet (60 mg Zn/kg DM) ad libitum and group 3 received the same diet matched to the feed intake of the zinc-deficient rats. Alimentary zinc deficiency reduced the zinc concentration and the activity of the alkaline phosphatase in serum by 75 and 67%, respectively. The activity of the glutamate dehydrogenase and the concentrations of ammonia and urea in the serum of the zinc-deficient rats showed no significant differences compared with pair-fed control rats. On the other hand the hepatic activity of the mitochondrial localized glutamate dehydrogenase of the zinc-deficient rats was significantly increased and the carbamoylphosphate synthetase and ornithine carbamoyltransferase were reduced about half in comparison with both control groups. The activities of the cytosolic liver enzymes such as argininosuccinate synthetase, argininosuccinase and arginase were again significantly increased in zinc-deficient rats compared with both control groups. The increased hepatic activity of the glutamate dehydrogenase possibly led to an enhanced NH(3) elimination in addition to urea synthesis. The typical reduction of feed intake in consequence of zinc deficiency is therefore not the cause of hyperammonaemia due to disturbed urea synthesis, as has been hypothesized in earlier studies.

A total metabolism trial was conducted in eight adult sows to compare the energetic utilization, nitrogen balance, and passage rate of retrograded starch (RGS) with that of pregelatinized wheat starch (PWS). The starch was added at levels of 12 and 24 g/kg W0.75 to a basal ration that covered the maintenance requirement. Each animal received all four treatment combinations in a change-over design. At the start and end of the trial all sows were fed the basal ration alone. Feeding took place twice daily. During each 3-week metabolism period a complete balance measurement was performed for all animals, with 6 daily collections of feces and urine and a 48-h gas exchange measurement in a respiration chamber. The sows' heat production and energy retention were calculated by the carbon-nitrogen balance method and the RQ method. Digestibility and metabolizability of energy and energy retention were lower in the basal ration with RGS supplement than in the PWS supplemented ration. With regard to N exchange, sows supplemented with RGS excreted more N in the feces and less N in the urine, whereas N retention was equal with both rations. The production of CH4 was higher with RGS than after feeding pregelatinized wheat starch. When compared with the nonsupplemented basal ration, the fecal volume was unchanged with PWS but significantly increased with RGS. The feed passage, measured as the mean retention time of a marker in the digestive tract, was 86 h on the basal diet, falling to 75 h with PWS supplementation and 65 h with RGS. The utilization of the supplemented energy was 12% lower for RGS compared with PWS. This difference was due to a reduction in the digestibility and intermediate utilization of the energy. The amount of metabolizable energy was calculated as 16 kJ/g and the net energy as 12.5 kJ/g RGS. The results of the trial underline the importance of retrograded starch as a fiber type nutrient and the associated advantages for the bowel function. The energetic utilization on the other hand is only slightly lower than that of non-resistant starch; unlike pure fibrous feed materials, RGS can therefore not be regarded as a "low energy" substance.

The first clinical studies with the application of growth hormone (GH) under postoperative and post-traumatic conditions date back to the early 1960s. The introduction of recombinant human growth hormone made the drug generally available for clinical studies. Administration of GH after elective general surgery improves nitrogen balance. Interruption of the post-traumatic hypermetabolism has been occasionally described, but most studies only demonstrate a slight reduction of the catabolic response. An increasing number of papers report positive influence of GH on wound healing, especially skin graft donor sites. The impact on the immune system has yet to be clarified. This paper gives an comprehensive overview of the current state of knowledge of the clinical effect of GH in various surgical specialties with special respect to septic conditions, burns, trauma, and wound healing.

In connection with the utilization of glycerol, which could become available as a by-product of the fuel production from rapeseed the influence of glycerol feeding with rations of low crude protein content was proved. 61 male day old broiler chickens received ad libitum 8 experimental rations based on maize and soybean meal. The experimental design included 3 factors: 15 or 18% CP; supplementation of essential amino acids or not and a content of pure glycerol of 0 or 10%. During the experimental feeding of 23 days body weight gain, feed conversion ratio, N-balance and the intake and excretion of glycerol was obtained. At the end of the trial the utilization of 15N-methionine and the glycerol content of blood plasma, liver and breast muscle was estimated. Due to the low crude protein content of the rations the body weight gain and N-balance was very low (BWG day 1 to 23: 8.6 to 17 g/animal.d; N-balance day 19 to 23: 0.4 to 1.0 g N/animal.d). The supplementation of essential amino acids was the factor with the highest improving effect on the body weight gain, feed conversion ratio and N-balance. Especially at the begin of the trial animals which received 10% glycerol had have an increased feed intake. The excretion of the supplemented glycerol by excreta amounted to 26% of the intake. However, the glycerol content of the rations did not effect body weight gain, feed conversion ratio, N-balance or utilization of 15N-methionine significantly. The assumption of a saving effect on glucoplastic amino acids due to glycerol feeding could not be manifested. In the mean feeding of glycerol elevated the glycerol level in blood plasma in comparison to the basal level up to 23 times (from 0.6 to 13.6 mumol/ml) and in the breast muscle up to 19 times (from 0.4 to 7.5 mumol/g). Nevertheless, these values were lower than the basal level of glycerol in the liver (17.1 to 19.0 mumol/g), which was significantly increased by glycerol feeding to 128%. Regarding the utilization of glycerol as a by-product of the production of renewable fuels it can be concluded that on the basis of the estimated parameters 10% pure glycerol in broiler rations instead of corn starch is without adverse effects.

In a first trial glycerol was tested as a feed ingredient for broiler chickens. The influence of glycerol supplementation on weight gain, feed intake, feed conversion ratio and N-balance was proved. 90 Broiler chickens (Lohmann Meat) were fed ad libitum in 6 groups with nearly isoenergetic diets based on corn and soybean meal with 23% crude protein and 0; 5; 10; 15; 20 or 25% pure glycerol in the DM. During a feeding period of 31 days animals had have a very good intake of all experimental diets. The highest weight gains were observed in the groups with 5 and 10% glycerol (34.9 and 35.3 g/animal.d, resp.). However, this effect was not significant compared to the control group (34.3 g/animal.d), but was significant superior to the gain of groups with 20 and 25% glycerol in the diet (30.2 and 26.6 g/animal.d, resp.). The feed conversion ratio was unchanged up to 10% glycerol (1.65 kg/kg gain) and rose to 2.08 kg/kg gain with 25% glycerol. Up to 20% glycerol the N-balance (1.6 to 1.8 g N/animal.d) was positively correlated with the glycerol content in the diet (r = 0.98). The estimation of the plasma glycerol level 2 hours after feeding indicated a remarkable increase already with a 5% supplementation of glycerol from 0.65 (control) to 4.36 mmol/l. Further supplementation caused on average 11 to 54 mmol glycerol/l varying considerably between the individual animals. In general 25% glycerol in the diet caused the lowest performance and pathological changes in the crop epithelium, liver and kidneys. From the point of view of weight gain, feed intake, and feed conversion ratio as well as N-balance a supplementation of 5 to 10% glycerol seems to be beneficial.

A varied, well-balanced, healthy diet, rich in carbohydrates, is one of the cornerstones of sports nutrition. In addition, an equilibrated supply in energy and nitrogen, the ideal distribution of the nutrients (6 to 9 g carbohydrates per kilogram body weight, 1 to 1.5 g fat per kilogram body weight, 1.2 to 1.8 g protein per kilogram body weight), a well-balanced fluid intake and the choice of food with a high density of nutrients constitute an important cornerstone. All the forementioned elements, which are contained in a basic nutrition, guarantee the needs of the micro- and macronutrients in combination with a cautious substitution of minerals, trace elements and vitamins. The endurance capacity is supported by this high-quality basic diet which can be modified minimally during performance and for regeneration.

Aim of the studies was to attain new scientific findings for the influence of the physiological state of sows (non-pregnant and pregnant respectively) on energy and nitrogen metabolism. The experiments were carried out according to a 3 x 3 factorial experimental plan with 3 variants of litter number (1, 2 and 4) and 3 variants of energy supply (120, 100 and 80%). Within the variants the non-pregnant and pregnant sows were fed equally related to the metabolic live weight. The metabolism measurements run from the 1st to the 115th experimental and gestation day respectively. The methods of indirect calorimetry and slaughtering technique were applied. The chemical composition of the whole bodies of the non-pregnant sows was like that of the maternal bodies of the pregnant sows (dry matter 410 g/kg, protein 160 g/kg and fat 210 g/kg). The physiological state for the sows did not influence the nutrients digestibility (OM 77.0 and 76.7%) and the energy metabolizability. About conformable intakes of metabolizable energy (601 and 586 kJ/kg LW0.75.d) and of digestible nitrogen (0.77 and 0.75 g/kg LW0.75.d) in non-pregnant and pregnant sows resulted in higher deposition of energy (64 and 79 kJ/kg LW0.75.d) and of nitrogen (0.15 and 0.19 g/kg LW0.75.d) in the pregnant sows due to energy and nitrogen deposition in the conception products and in the reproductive organs. The energy maintenance requirement and the partial efficiency of the energy utilization for the deposition as well as the nitrogen maintenance requirement and the partial efficiency of the nitrogen utilization for the deposition in the non-pregnant and the pregnant sows were determined.

2,6-Diaminopimelic acid (DAPA), ribonucleic acid (RNA), 15N, D-alanine (D-ALA) and the amino acid profiles (AAP) were compared as microbial markers for determination of the microbial protein synthesis in the rumen. Three dairy cows (Schwarzbuntes Milchrind, LW 602 kg), each fitted with a rumen cannula and a re-entrant cannula in the proximal duodenum, were offered four isoenergetic and isonitrogenous diets (mean daily intake 15.0 +/- 0.45 kg DM; forage: concentrate = 50:50) in a periodic experiment. The diets contained soyabean extracted meal, meat and bone meal, pea meal and dried clover as major sources of protein. On the 4th day after administration of 9 g 15N-labelled urea (95 atom-% 15N-excess) per day, samples of rumen fluid and duodenal digesta were obtained 3 h after feeding. The bacteria were isolated by differential centrifugation. Bacteria harvested from the rumen had significantly higher 15N enrichment and D-ALA: N ratio than 'duodenal' bacteria. However, DAPA: N ratio was higher in 'duodenal' bacteria compared to rumen bacteria. There were no differences in RNA: N ratio between rumen and 'duodenal' bacteria. The source of the bacteria in the digestive tract has an influence on the ratio of microbial N: total N, especially when 15N, AAP, DAPA and D-ALA but not RNA were used as markers. The most reproducible method was D-ALA (C.V. 4.7 for rumen and 6.8 for 'duodenal' bacteria) followed by 15N (10.8 resp. 4.8) and RNA (9.7 resp. 8.2). The results obtained with 15N and D-ALA agreed closely at the same source of bacteria. The RNA method reached the level of these markers (15N, D-ALA) when the bacteria were isolated from the duodenum. It is concluded that D-ALA (bacteria isolated from rumen and duodenum) and also 15N (bacteria isolated from duodenum) were the best markers for estimation of the microbial protein synthesis.

Aim of investigations was to measure lysine utilisation under dietary conditions which could have negative effects on well known relation between limiting amino acid and level of N-utilisation. Incorrect conclusions about level of lysine availability (efficiency) could be drawn under such conditions. Therefore N-balance trials were done with 32 female pigs (35-45 LW, fitted with urine bladder catheters), based on semisynthetic diets (wheatgluten / cornstarch) supplemented with glutamic acid as additional nitrogen source. Lysine concentration in the protein was further reduced by this way near to N-balance +/- 0. Data calculation followed a further developed N-utilisation model from Gebhardt (1966). Experimental conditions resulted in disturbed relationships between lysine concentration and protein utilisation and led to the conclusion, that N-balance trials related to estimation of amino acid efficiency in feed proteins resp. to amino acid requirements should be realised under conditions of > 500 mg / LWkg0.67 daily N-balance connected with > 2000 mg/LWkg0.67 daily N-intake.

In 23 litters, each with 10 or 11 piglets, the energy and nitrogen metabolism was measured on base of 218 body analyses in suckling piglets and on base of 96 total metabolism experiments in early weaned piglets, combined with 134 body analyses. The studies were carried out as part of a complex experimental program for the factorial derivation of energy and protein requirement of piglets and for measuring the milk production of lactating sows. The energy maintenance requirement of suckling piglets (sow's milk nutrition, I) and of early weaned piglets (sow's milk replacement on the basis of cow's milk, II) amounted to 468 (I) and 451 kJ (II) metabolizable energy per kg LW0.75 . d, the utilization of of metabolizable energy for energy deposition to 70(I) and 72% (II). With mean live weight gains (LWG) of 161 and 162 g per animal and day the cost per kg LWG amounted to 19.9 and 20.4 MJ gross energy, 19.3 and 19.4 MJ metabolizable energy as well as 14.4 and 14.2 MJ net energy-fat in suckling and early weaned piglets resp. The mean energy content of the LWG amounted to 8.9 (I) and to 7.9 MJ/kg (II).

In experiments with Galloway (G), Highland (H) and Black-White Dairy (B) cattle no significant differences between the breeds were measured in the energy and nutrient digestibility and energy metabolizability of rations with high variation in the nutrient composition. In H and B cattle no differences existed in digestibility in relation to the environmental temperature (30, 18 and 3 degrees C). Lowering the environmental temperature from 18 to 12 and 4-6 degrees C resulted in no changes of heat production in G and H but in B heat production increased about 6% and 20% respectively.

The fecal microflora of the breast-fed infant consists of nearly 100% Bifidobacteria. The importance of this long-known and unique phenomenon is still not clearly understood. Likewise, the presence of lysozyme in the feces of breast-fed infants, which is administered in significant amounts with the human milk is not adequately known. New hints and hypotheses concerning digestion in ruminants are cited. In ruminants Lysozyme c functions as digestive enzyme in the rumen. Lysozyme causes lysis of the bacterial cell membrane leading to the release of bacterial contents i.e. proteins. The proteins synthesised in bacteria are the main source of nitrogen for ruminants. The hypothesis is established, that the enormous amounts of Bifidobacteria in the colon of the human newborn can be made of use in a similar way. The lysozyme in the colon of breast-fed infants leads to lysis of Bifidobacteria in connection with tryptic digestive enzymes, in turn leading to release of proteins and protein substances. It has recently been demonstrated that catabolic products of these proteins can be absorbed in the colon. The same group has shown that lysis of Bifidobacteria can take place in the presence of lysozyme in connection with trypsin.

Injury and stress are accompanied by a characteristic hormonal response and altered energy utilisation. Hyperglycaemia and negative nitrogen (N) balance are the leading symptoms of the metabolic changes in the post-operative state. In a prospective, randomised study the efficacy and metabolic effects of glucose-xylitol (GX) 35% (1:1) versus glucose (G) 40% were investigated in patients undergoing major surgery. METHOD. Twenty-four patients undergoing abdomino-thoracic oesophageal cancer surgery were treated in a standardised manner. Total parenteral nutrition was administered over 6 days (kg body wt.-1/day): day of surgery 1-1.25 g carbohydrate (CH); 1st postoperative day (POD) 1.5 g CH, 1 g amino acids (AA); 2nd POD 3 g CH, 1.5 g AA, 1.0 g fat; from 3rd POD 3 g CH, 1.5 g AA, 1.5 g fat (CH GX35% (n = 12) or G40% (n = 12), AA Intrafusin 15%, fat Intralipid 20%). Daily and cumulative N balances, blood-G profiles, blood chemistry, and physical parameters were determined. Glucagon and insulin profiles, CH losses, and oxalic acid secretion were measured. RESULTS. Both groups were comparable for age, body mass index, clinical and physical parameters, and blood chemistry. Mean cumulative N balances after 6 days were -12.0 +/- 16.3 g N for GX35% and -5.6 +/- 19.4 g N for G40% (n.s.; Wilcoxon, P < 0.05). Blood G was similar for both groups with values ranging from 130 to 240 mg/dl on the day of surgery and below 150 mg/dl on the consecutive days. In each group 1 patient needed additional insulin therapy. Glucagon and insulin levels did not show a significant difference between the groups. CONCLUSION. No difference in tolerance and efficacy of nutritional support by GX versus G at a dose of 3 g.kg body wt.-1.d in oesophagectomised patients could be observed. Similar blood G profiles were in accordance with comparable glucagon and insulin levels. Because of the high standard deviations of N balances, differences in efficacy could not be proven. A significantly lower level of pseudocholinesterase (PCHE) for G40% on day 7 might indicate enhanced hepatic protein synthesis in the GX group.

The influence of physical treatment-expansion and flaking-on crude proteins degradability in the rumen was studied in maize, maize-gluten feed, rape extracted meal and in the expanded one at 120 degrees C and 150 degrees C, rape cake, wheat and flaked wheat by in sacco method. The enzymatic digestibility of crude protein in the rumen undegraded residues of the above mentioned feeds was determined by an enzymatically in vitro method. The treatment of feed decreased significantly the original solubility and theoretical degradability of crude proteins, and the amount of undegraded crude proteins was increased. Positive influence on the amount of enzymatically digested crude protein was determined in rape expanded at 120 degrees C and 150 degrees C (60, 61 and/or 68%). Flaking of wheat had a similar effect. Enzymatic digestibility at undegraded rests where increased by 8-10% after the heat treatment and it remained almost unchanged in expanded maize-gluten feed.

The energy and nitrogen metabolism of pregnant sows was measured with the method of indirect calorimetry in dependence on the number of gestation (1,2 and 4), on the energy supply (120, 100 and 80% of the requirement recommendation) and on the gestation stage. Values of maintenance requirement and of energy and nitrogen utilization for body deposition were calculated on the basis of results of energy and nitrogen metabolism. The energy maintenance requirement increased from 389 to 435 and 473 kJ metabolizable energy per kg LW0.75.d with rising number of gestation. The heat production increased from 85th to 115th day of gestation by 6%. The efficiency of the partial energy utilization for the energy deposition amounted to 66% on the average. The efficiency of the partial utilization of digestible nitrogen for the nitrogen deposition was calculated to 75%. The nitrogen maintenance requirement values amounted to 0.5 and 0.4 g digestible nitrogen per kg LW0.75.d in the 1st and 2nd half of gestation.

The estimated value of true digestibility of food and feed proteins is in dependence from the excretion of metabolic faecal nitrogen (MFN). Results of many authors showed that a high fibre content of the diet increase the MFN-excretion and lower the true digestibility of the diet protein. The exact estimation of MFN is only possible with isotopic methods. The labelling of feed proteins with isotopic nitrogen (15N) is possible in experiments with small animals. In big animals (pigs) the utilization of recycled 15N is too high following the long transit time of non digested 15N-labelled feed protein and the parallel 15N-labelling of MFN. The best method for the estimation of true digestibility of proteins is the method with 15N-labelled animals and the differentiation between nonlabelled undigested feed protein and the 15N-labelled MFN in faeces. The estimation of digestibility of essential amino acids at the end of the ileum as a measure for protein quality is not in advantage because the bacterial breakdown and synthesis of amino acids in the small intestine is unknown. The estimation of the biological value (BV) of proteins with the classical method is useful when the exact MFN was determined. The classic formula of BV [formula: see text] is only applicable in experiments with growing animals with nitrogen retention. This result of BV value is in agreement with the method only valid for growing animals with N-retention and not for animals or human beings in maintenance. The measurement of a BV of proteins with animals in maintenance is possible when the animals are labelled with 15N. The 15N-loss of the animal after the feeding of different protein sources is the smallest when the amino acid pattern of the protein is adapted to the need of amino acids for the maintenance metabolism of the animal. It was found that proteins with a high content of glutamic and aspartic acid (proteins of grains) are better proteins for the maintenance metabolism as animal proteins. Measurements with the method of the oxydation rate of essential amino acids showed that the amino acid pattern of wheat protein is in agreement with the need of amino acids for maintenance of the adult men. The evaluation of protein quality in animal nutrition for growing or lactating monogastric animals is in the present time the balance of essential amino acids in the feed protein and the need of this amino acids of the animals.

Chopped wheat straw was homogeneously mixed with urine of horses (5.75 gN per 1, 16.88 atom-% 15N-excess) and airtightly stored in plastic containers for 6 months. Three rumen fistulated sheep and goats each were fed with untreated or urine treated straw. Concentrate was added to straw. Untreated and urine treated straw were given in nylon bags and incubated in the rumen of sheep and goats for 1, 3, 6, 12, 24, 48 and 72 hours. A three compartment exponential function was used to fit the measurements of 15N-excess and 15N-amount of bag content. The curves and the calculated partial Y-values of the three compartments show the inflow and outflow of 15N into or from the bags and allow conclusions about the binding of urine N. Most N of urine was not compactly bound by straw during storage. Primarily microbial N was attached to the straw in the rumen. About 6% of urine N were bound more compact to the straw. Similar curves were calculated for 15N-excess and 15N-amount of nylon bags. The curves allow conclusions about tracer flows without quantitative knowledge. There were no significant differences between animal species.

The endogenous N in ileal digesta of pigs was estimated in two experimental variants. In variant 1 the crud protein content of a wheat-maize-fish meal diet was 18% and the crude fibre content was 1.9% (diet 1) and 2.7% resp. (diet 2). In variant 2 the crude protein content was 12.5% (wheat-maize-diet) and the crude fibre content was 4.1% (diet 3) and 5.5% resp. (diet 4). The higher crude fibre content of the diets 2-4 was provided by means of a supplementation with partially hydroyzed straw meal plus pectin (2:1 w/w). Four miniature pigs with an average initial body weight of 29 kg, were fitted with a ileocaecal re-entrant cannula and received each one of the four different diets. 15NH4Cl, added to the diets, was given for 5 days (150 mg 15N-excess/kg0.75 BW*d) to label the animals with 15N. Ileal digesta, urine and faeces were collected over 24 hours on 8th, 10th and 12th day after the first intake of 15N. The 15N-excess of urine N was used as the comparative measure of 15N-excess of endogenous protein. The amount of nitrogen collected in ileal digesta was in order of the diets 1-4 = 258, 299, 200 and 224 mg/kg0.75 BW*d and of these amounts were 50.1, 52.1, 56.1 and 50.4% of endogenous origin. This were corresponding, after conversion into crude protein to 9.1, 11.2, 10.8 and 11.0 g/100 g crude protein intake or 16.9, 19.7, 13.8 and 13.4 g/kg dry matter intake, respectively. The bacterial N-flow were in order the diets 1-4 = 94.0; 72.7; 55.8 and 52.6 mg/kg0.75 BW*d and 73, 46, 50 and 47% resp. of the endogenous N or 36, 24, 28 and 24% of the ileal total N. The results show, that the absolute amounts of endogenous and bacterial N at the terminal ileum were significantly increased by a higher crude protein content of the diet. The percentage of endogenous and bacterial N on the total N of the ileal digesta was not affected neither by the crude protein content of the diets nor by the fibre supplements.

The chemical composition and the energy content of the conception products, the reproductive organs and the live weight gains or losses of pregnant and lactating sows were determined in dependence on the litter number (1, 2 and 4) and the energy supply (120, 100 and 80% of requirement recommendation) of sows as well as on the course of gestation and lactation. The results will be used as a basis for factorial derivation of requirement recommendation. The deposition of protein and energy in the conception products in dependence on the time is characterized by an exponential function. The deposition of nutrients and energy in the conception products is increased with rising litter size. The deposition of nutrients and energy per fetus is lower in the litter number 1 than in the litter number 2 and 4. The energy supply in the selected limits has no significant influence on the litter size as well as on the intrauterine deposition of nutrients and energy. The litter number, the energy supply as well as the course of gestation and lactation influence considerably the weight, the chemical composition and the energy content in the mammary gland. The chemical composition and the energy content of the live weight gains or losses of pregnant and lactating sows are strong affected by the energy supply. The increased energy supply of the pregnant sows is connected with increased live weight gains and with increased contents of dry matter, fat and energy however decreased contents of protein in the live weight gains. The live weight losses of the lactating sows are connected with mobilisation of body fat and body protein. The proportion of body fat to body protein degradation is increased with increased losses of body weight. Regression equations are calculated for the relationships between course of gestation and lactation respectively and deposition of protein and energy in the conception products, reproductive organs and maternal live weight gains or losses of sows.

The aim of the experiments was to work out new results for a factorial derivation of energy and protein requirement. The experiments were carried out according to a 3 x 3 factorial experimental plan with 3 variants of litter number (1, 2 and 4, age of sows) and 3 variants of energy supply (120, 100 and 80% of the norm of pregnancy, continued in lactation with 80, 100 and 120%). Methods of the indirect calorimetry and the slaughtering technique were used. The mean cumulative live weight changes of the sows for the 9 experimental variants amounted from 13.1 to 63.2 kg for the 115 days of pregnancy and from -17.0 to 6.8 kg for the first 26 days of lactation. The chosen variation of energy supply of pregnant and lactating sows had no relevant effect on the reproductive performances, measured by litter size, weight of conception products, litter weight at birth and the quantity of milk per sow and day respectively. In comparison with the sows of litter number 1 the sows of litter number 2 and 4 had higher litter weights at birth and higher milk quantities.

The study is based on the results obtained from the slaughter of 5 sows on the first day of pregnancy and the first day of the experiment respectively (pregnant and non-pregnant sows resp.), of 43 pregnant sows on the 56th, 84th, 98th, 105th and 113rd day of gestation as well as 17 lactating sows on the 26th day of lactation. The animal bodies of pregnant sows were divided in 15 fractions and those of non-pregnant and lactating sows in 12 fractions. The investigations were carried out with 3 x 3 variants of litter number (1, 2, 4) and energy supply (120, 100, 80% of requirement recommendation). The chemical composition and the energy content of the animal body fractions as well as their relative portions of the empty body were largely constant during the course of gestation with the exception of the reproductive organs and the conception products. The physiological stage of lactation connected with limited mobilization of body reserves resulted in a reduction in fat content of some body fractions as well as a limited increase of the portions of body organs contrary to the portions of body tissues of the empty body. In comparison with sows of litter numbers 1 and 2 the sows of litter number 4 were characterized by higher portions of bones and meat, valuable parts as well as by smaller portions of depotfat and meat from head and belly of empty body. The raising of the energy supply of the pregnant sows increased the portion of the depotfat and decreased the portion of the meat, valuable parts of the empty body. The chemical composition of the reproductive organs and the conception products as well as the portions of these fractions of the empty body were influenced strongly from the course of the gestation and lactation resp. The portions of the reproductive organs and of the conception products are small (related to energy < or = 5.7 and < or = 2.6% resp.)

In growing barrows (live weight 17-30 kg) 3 g P/kg DM feed resulted in comparison to 6 g P/kg DM in 8% lower live weight gain. The lower live weight gain had no relation to N- and energy retention. The lower P feeding has only low effect on energy excretion in faeces and urine (1% of gross energy). A submarginal P feeding has no influence on N- and energy metabolism of growing pigs.

The influence of litter number (1, 2 and 4, age of sows) as well as gestation and lactation stage of sows on the chemical composition and on the quantities of protein and fat of their bodies was investigated. The slaughter of 46 pregnant, 18 non-pregnant and 17 lactating sows were carried out at the 1st, 56th, 84th, 98th, 105th and 113th day of gestation, 113th day of experiment (non-pregnant sows) and 26th day of lactation. The results were related to the sows' energy supply (120, 100 and 80%) with equal supply of protein, vitamins and minerals. Within the tested litter numbers the chemical composition of the bodies was nearly constant during the whole time of gestation and lactation. A good agreement existed for the chemical composition of the sows' bodies of litter number 1 and 2. In comparison to them the bodies of litter number 4 contained more protein and less fat per kg dry matter. The quantities of body protein and fat increased in the gestation and decreased in the lactation period, in each case the quantities of fat exceeded than the quantities of protein. The quantities of body protein increased with higher litter number. The quantities of body fat increased from litter number 1 to 2 and were nearly equal in the sows of litter numbers 1 and 4. Within one litter number the amounts of body protein and fat attained the same level in pregnant, non-pregnant and lactating sows.

The investigations were carried out in order to develop foundations for a complex growth model including the effect of N-efficiency mechanism first of all for the rat. Therefore N-balance trials with rats of different live weights were made using diets of equal protein quality. The curve of the regressively calculated N-efficiency function courses relatively linear in its lower part, i.e. for low N-intakes. The protein quality value "A.b" was proved to be constant for all investigated live weight ranges. In similar trials with different protein qualities was also found a linear course for low N-intakes. The regressively estimated N-maintenance requirement (for N-Intake = 0) related to metabolic live weight (NMR/LWkg0.67) amounts to 180 mg/d. In addition endogenous N-excretions were determined in 15N tracer experiments on animals of different live weight fed graduated amounts of a quality constant protein. The NMR-values (sum of endogenous excretions from faeces and urea) depend on the level of N-intake, i.e. they can not be considered as constant. The endogenous faecal N-loss related to metabolic live weight is relatively constant indeed, whereas the amount of endogenous urea N-loss is dependent on the level of N-intake. Therefore calculations based on the N-efficiency curve, e.g. amino acid requirement dependent on performance and prediction of N-deposition respectively, should not be carried out on the basis of "N-retention" (N-balance + NMR) but only on the basis of N-balance.

In a preexperiment of 12 days fishes (Cyprinus carpio L.) were labelled with 15N by means of 15NH4Cl and 15N-urea resp. in the aquarium water and by feeding a protein free diet. 15NH4Cl yielded a higher atom-% 15N excess (15N') in the tissues of fishes. In the main experiment 75 fishes (Cyprinus carpio L.) were 15N-labelled with 100 mg 15N'/l water from 15NH4Cl (95 atom-% 15N') in a protein free preperiod of 12 days. In the following main period the fishes received different protein sources in their diets in maintenance. A group of 20 fishes received an animal protein (fish meal) and two groups of 20 fishes each received plant proteins (soybean meal and wheat gluten resp.). The atom-% 15N' reached after the 15N-labelling period following values: digestive tract with content--7.15, liver--5.65, gills--5.89, muscle--0.81 and chorda dorsalis--1.09 respectively. During the main period (with protein feeding) the atom-% 15N' decreased in the tissues with high protein turnover (liver and gills) on the 2nd and 4th day to 4.31 +/- 0.11 (animal protein) and 4.64 +/- 0.14 (plant proteins) in average. The corresponding values in the tissues with low protein turnover (muscle and chorda dorsalis) were 0.73 +/- 0.04 and 0.80 +/- 0.04 atom-% 15N' in average. From the measurements on the 6th, 8th and 10th day of protein feeding resulted an atom-% 15N' in average of liver and gills of 4.08 +/- 0.13 (animal protein) and 4.11 +/- 0.15 (plant proteins). In muscle and chorda dorsalis the atom-% 15N' ascended in this time upon 0.80 +/- 0.04 (animal protein) and 0.90 +/- 0.03 (plant proteins). It seems that the protein metabolism of fishes is favoured from the amino acid of plant protein in comparison to animal protein to reduce the 15N-loss of the 15N-labelled body in maintenance, like the results from experiments with rats (Hernandez et al., 1981).

Two feeding regimes were used for investigation into the effect of meal frequency on the lysine requirement in chickens estimated with metabolism-oriented determination. 1-day-old male broiler chickens were fed either twice a day for 1 hour (one group) or 6 times a day for 1/2 hour (other group). 7 to 21 days posthatching the birds received a wheat-wheat gluten diet which was L-lysine-supplemented at 6 levels. Using lysine deficient diets chickens fed twice a day eat more and grow faster than chickens fed 6 times a day. The N-balance was 6 to 7% higher in the case of the feeding regime 2 times a day. After feeding period 14C-U-L-lysine was injected intravenously and 14CO2-excretion measured. The estimated range for lysine requirement was 11.9-13.1 g lysine/kg DM and 13.1-14.3 g lysine/kg DM for chickens fed 2 times and 6 times a day, respectively. A feeding regime of 6 meals a day does not improve the utilization of diets contains crystalline lysine compared with feeding of 2 meals a day.

The validity of residues from hydrolysis of soya bean meal for production of lysine was tested in a growth experiment with 2 groups of 25 cross breeding lambs as well as in a N-balance trial with 5 lambs. The animals in the growth experiment started with an average body weight of 25 kg. An industrially produced concentrate for lamb fattening was given to the animals of the control group. To the second group a straw-concentrate mixture was given, containing 30% straw, 52% barley, 5% soya bean meal, 5% dried beet pulp and 5% of hydrolysis residue. The mixture included 10.71 MJ ME resp. 5.51 MJ net-energy fat (cattle) and 166 g digestible crude protein per kg dry matter. The lambs of group 2 showed an 8% lower intake of DM, connected with a 26% intake of energy and 32% lower intake of DCP in comparison to the control group. The average daily body weight gain was 374 g for the control group and 241 g for group 2 respectively, the difference being statistically significant. The feed/gain ratio was in group 2 = 14% higher for energy and 6% higher for DCP than in the control group. The N-balance trial resulted in a N-retention of 25 percent of the N-intake. The results approved the possible use of 5% of the hydrolysis residue product for 2% crude protein in straw-concentrate mixtures for ruminants.

Because of the low efficiency of N utilisation, animal husbandry is the main contributor of N pollution into environment within agricultural production systems. Possible solutions are to regulate the fertilizing and animal stocking rate per hectare as well as improving the efficiency of N utilisation in animal nutrition. Production of pig manure is determined by the kind of animal production, feeding level, performance level and N intake. Increasing performance improves nutrient utilisation which in turn reduces the amount of manure and manure-N per production unit. N intake especially influences N excretion. Therefore feeding in exact relation to the requirement is most important for an ecological pig husbandry. The proportion of the easily soluble urinary N to faecal N can be lowered by diet composition, mainly by higher amounts of bacterial fermentable substances. Thereby the ecological quality of manure is improved. Lowering of excessive N excretion in pigs via feeding measures is possible in two ways, (1) by exact adaptation of the protein supply in agreement with the changing requirements and (2) by improving the dietary amino acid balance. In the first case N excretion in fattening pigs and sows can be reduced up to 12%. In the second case lowering dietary protein and supplementation with crystalline amino acids diminished N emission up to 40% to 50%, practically achievable are under present conditions about 20%.

The effect of feeding frequency (daily 2 times feeding for 1 hour or 6 times feeding for 30 minutes) and a different methionine content of the diet on weight gain, N-balance and metabolic 35S-methionine degradation was investigated in broiler chickens. Weight gain and N-balance were not improved by increased feeding frequency. At the high feeding frequency, weight gain and N-balance were even depressed when diets with methionine deficiency (without methionine supplementation) were fed. No effects of feeding frequency and the amount of DL-methionine supplementation on the level of excreted 35S after i.v. injection of 35S-methionine were observed.

Wistar rats of a live weight of about 100 g received in 26 groups (4 animals/group) diets, each with a different lysine content. The rations given supplied the animals with 75%, 100% or 125% lysine of the calculated requirement. The source of protein in the diets was: barley (B), wheat (W), wheat gluten (WG), isolated soybean protein (assay protein) (S) or soybean meal (SM). For WG and S only the lysine levels 100% and 125% (SM = 116% and 125%) could be achieved. All diet groups were fed for 10 days with and without antibiotics (7 g Nebacitin/kg feed-DM). During the 7-day-period of the main experiment all 24 rations were supplemented with 0.5 g 15N-lysine/kg DM (48.3 atom-% 15N-excess, alpha-aminogroup 95% 15N-labelled). The nitrogen balance was improved only after feeding antibiotics with the diet S 100. It may be supposed that Nebacitin saved the second limiting amino acid methionine against microbial degradation in the digestion tract. The biological value (BV) of feed-proteins declined in the case of the diets B and W in the presence of antibiotics because the absorbed nitrogen was higher, this calculation basis for BV was therefore also higher without an improvement of the N-utilization. The 15N-excretion in faeces was significantly lower after feeding the diets B, W and WG with antibiotics. The 15N-excretion in urine was elevated in the most cases of the antibiotic supplement. The determination of a gross utilization of lysine and 15N-lysine resp. in relation to the lysine retention (availability) was not possible, neither using a labelling of diets with 15N-lysine.

After N-balance experiments with leghorn-hens of five different genetic origins in the top laying period, the advanced laying period as well as at the end of the laying period and with feeding of soybean meal/fish meal protein, the nitrogen maintenance requirement per live weight kg0.67 was ascertained regressively by approximation of the N-balance from N-increasing experiments to an exponential function. The Net Protein Utilization (PNu) curve and the apparent Net Protein Utilization (PEW) curve could be described as utilisation values from the N-retention curve (e-function). Moreover the relation between N-intake/LW kg0.67 and egg-N-discharge/LW kg0.67 from N-balance made it possible to estimate N-retention in the body. Finally, capability of the five origins at equal protein and S-AA intake respectively were compared.

During the milk feeding period (ca. 55th day of life) and 2 weeks after the milk feeding period (ca. 80th day of life) the influence of a hay quota in the ration (on DM basis) of 6, 10, 14 and 18% in the milk feeding period and of 16, 23, 31 and 37% in the period after milk feeding was tested as to ruminal N metabolization with calves supplied with duodenal re-entrant cannulae. The increase of the hay quota in the ration for ruminating calves reduced as a tendency duodenal NAN passage, its bacterial N-quota, post-ruminal NAN digestibility and, due to a worse utilization of available N for bacterial N-synthesis, bacterial N-synthesis rate. The apparent fermentation of organic matter was, as a tendency, increased with the growing hay quota in the ration.

In 9 experimental periods on four adult bulls (LW 550 kg) fitted with re-entrant cannulae in the proximal duodenum isoenergetic rations were used on feeding level 1.7 with ground barley, ground maize or fresh potatoes as starch sources. The net energy parts of these concentrates in the ration amounted to 50, 25 and 10%. 50 to 80% of the ration DM consisted of dried grass and about 10% of sugar beet pulp. The dried grass supplied on an average 87, 79 and 62% of the feed crude protein. The intake of DM was 7.74 +/- 0.42 (mean +/- SD) kg/d. The energetic efficiency of microbial N synthesis in the rumen (g N/kg organic matter true fermented in the rumen, TFOM) was averaged 16.4 with a range of 10.6 to 21.4. The microbial efficiency achieved a maximum when the ratio of nitrogen-free extract to crude fibre in the diet was 1.7 and 2.1 with barley, 1.8 with potatoes and 2.1 and 3.3 with corn as starch source. Changes in the microbial efficiency were positively correlated with the rate of passage of non-microbial organic matter from the rumen (g/d) and with the duodenal flow rate (kg digesta/kg DM intake). The relation to the rate of carbohydrate fermentation in the rumen (in %) and to the amount of TFOM (g/d) was negative. The duodenal flow of microbial N and non-ammonia N (g/d) correlated negatively with the organic matter apparently fermented in the rumen (AFOM) and positively with the non AFOM. The amino acid (AA) profile of the duodenal protein was affected by the starch source. It was concluded that the metabolism of nitrogen in the forestomachs of cattle is affected by the source of starch and the ratio of forage to concentrate. There exists a relationship between both factors. The net synthesis of microbial protein in the rumen is not only the result of substrate fermentation. The passage of non-AFOM from the rumen significantly affects the energetic efficiency of microbial nitrogen synthesis and the duodenal supply of AA.

After a 9 day preparation period 42 Wistar rats (live weight 100 g) were fed a diet of 15N labelled wheat supplemented with the marker TiO2 (impulse labelling). At 7 time intervals (0.5 to 6 h after feeding) 6 animals were killed and thereafter total N, 15N and TiO2 levels were estimated in the digesta of different intestinal sections. The following results were obtained: The transit rate of the marker amounted to 10.3 +/- 0.62% per hour of the intake. The endogenous part of N increased during passage from stomach (3.5%) to duodenum (38.6%), jejunum (59.1%), ileum (64.8%), large intestine (78.3%) and faeces (87.7%). The apparent N digestibility in the stomach increased with time reaching 26% 6 h after feeding. In the whole small intestine it was 66.3%, in the ileum 78.9% and in the large intestine 90.4%. The true digestibility (6 h after feeding) showed the same course, but was always some units higher (stomach 33.3%, whole small intestine 82.5%, ileum 92.2% and large intestine 93.5%). Apparent and true digestibility values in the ileum correspond best to the data of precaecal digestibility; those of the large intestine correspond to the postileal digestibility. The N disappearance rate in the stomach is the sum of absorption rate (16%/h) and transit rate into the small intestine (12.4 +/- 1.6 mg N/h). Most absorption occurred during passage through the small intestine (2/3 of total absorption). The absorption in the small intestine was about 80% of the N amount flowing from the stomach into the intestine. The amount lay between 18.2 and 26.1 mg N/h and half of this was of endogenous origin. The reabsorption rate of endogenous N for the whole intestinal tract was estimated to be 91.4%. The N secretion into the whole intestine increased during the 6 h after feeding up to 85.5 mg (64% of N intake), for which 77 +/- 5.5% was secreted into the small intestine. Secretion into the stomach was relatively small and up to 4 hours after feeding, amounted only to 3.0 ... 6.7 mg N.

The fractional synthesis rates (FSR) for liver, pancreas, small intestine, large intestine, skeleton muscle and whole body protein were estimated with the help of the large dose method of McNurlan et al. (1979) and Garlick et.al (1980) using simultaneously [14C]lysine and [15N]lysine as flooding substances in growing rats. The following results and conclusions can be drawn: In the case of lysine as flooding substance the incorporation time (time from the injection up to killing the animals) can be fixed at 20 minutes. On principle lysine is suitable as flooding substance. [14C]lysine and [15N]lysine can yield identical values for FSR in the same animal. The variation coefficients of the FSR values were 7.3% (4... 12%) using [14C]lysine and 13.8% (9.5... 36%) using [15N]lysine (emission-spectrometry) as flooding substance. Using the mass-spectrometric method for measuring 15N-excess it is possible to obtain the same accuracy of result as in the case of estimation [14C]lysin. The main advantage of using 15N-labelled amino acids as flooding substances is the absence of any radioactivity. Therefore this method is also suitable for farm animals and--in combination with the indolent muscle biopsy--it may be used for men.

The aim of our experiments was to identify a restricted lysine bioavailability after heating of wheat gluten by estimating a reduced metabolic 14C-lysine degradation. In two trials, male broiler chickens were fed with six diets based on wheat and wheat gluten (gluten untreated or heated), but differing in lysine content according to lysine supplementation. In trial 1 animals were fed restrictively, in trial 2 they were fed ad libitum. For estimation of metabolic lysine degradation all animals received an additional i.v. injection of 14C-U-L-lysine 3 weeks posthatching, followed by hourly collection of 14CO2 up to 3 h after injection. There were no differences between groups receiving untreated or heated gluten concerning weight gain and N-balance if the lysine supplementation was medium or high. When applying a lysine supply close to the requirement level or above the requirement the lysine degradation to 14CO2 (% of the dose) and the specific radioactivity of CO2 in animals receiving heated gluten was significantly lower compared to the corresponding group with untreated gluten. It can be concluded that reduced bioavailability of lysine due to heat treatment of gluten might be indicated by means of weight gain or N-balance only at lysine supply levels below the requirement. In contrast, measurements of lysine degradation by means of 14CO2-excretion after i.v. lysine injection indicate the heat-damaging effect, especially at lysine levels close to the requirement.

In this review possibilities to reduce nitrogen excretion in fattening pigs are discussed. If the weight gain is high, the total nitrogen requirement for maintenance during the (shorter) fattening period is lower. Therefore the amount per fully grown animal is reduced. Diseases can increase the nitrogen turnover considerably. The optimal ratio of protein to energy for nitrogen accretion decreases during the fattening period. By reducing the protein content in the food in 3 steps (3 phase feeding, 160, 140 and 130 g crude protein/kg food) nitrogen can be saved. The addition of synthetic amino acids (lysine, methionine, threonine, tryptophane, isoleucine) allows a further reduction of the protein content in the food without loss of growth yield. The availability of amino acids in the food depends on their prececal digestibility. The main source of ammonia emission is urea, which is excreted renally. Since nitrogen over supply is mainly excreted by the kidney, the reduction of nitrogen by 3 phase feeding and addition of amino acids especially decreases ammonia emission.

Three heifers with live weights of 255, 261 and 300 kg were supplied with ileo-caecal re-entrant cannulas, jugular vena catheters and bladder catheters. The ration consisted of 4 kg maize silage and 4 kg wheat straw pellets. In a previous period 50% of the digesta flow was collected over 12 h/d on 5 consecutive days and stored in a deep-freeze. During the main period the re-entrant cannulas were disrupted and the flowing digesta was quantitatively collected. Precollected digesta and pectin were infused into the distal part of cannula hourly for about 30 hours. During the first 24 hours the digesta was also supplemented with 15N-labelled urea. The amount of pectin corresponded to about 10% of digesta dry mater. An analysis of urine, faeces, digesta and blood plasma were carried out. The application of pectin increased the 15N-incorporation in the bacterial protein of faeces from 4.7% (without supplementation in an earlier experiment) to 10.5% of the introduced 15N. The ammonia-fraction of faeces was markedly higher than the bacterial fraction. The 15N-utilization of urea by the microbes of large intestine was lower in the actual trial evident than with supplementation of starch in the anterior experiment. During the pectin administration the amount of urine increased in comparison with earlier experiments and according to the literature to about the 4.5 fold. The amount of passage of 15N at the ileum cannula (recycled 15N) was 3.8% of the 15N intake. It is the same amount as in experiments in which starch was applied.

The energetic utilization of rations with steamed potatoes (40 and 50% of DM of ration) was measured in 8 growing pigs, live weight 30-70 kg by means of respiration experimental techniques. The experiments were carried out using the difference method (3 periods feeding basal diet and 3 periods feeding basal diet plus potatoes). The digestibility of energy of the steamed potatoes amounted to 94%, that of organic substances 96% and that of crude protein 77%. The metabolizable energy amounted to 16.1 and the energy deposition to 12.0 MJ/kg DM of steamed potatoes, 74.5% utilization respectively. The results in growing pigs are very similar to the results in adult pigs.

In two digestibility and N-balance experiments the following solvent extracted meals were examined in a grain (barley and wheat in equal parts) or in a starch diet with four female pigs/group fitted with urethra catheters during the 5 days sampling period: 48% soyabean meal (SBM) (1), 24% conventional rapeseed meal (RSM) (2), 24 (3) or 48% (4) RSM from a newly bred low glucosinolate variety, groups 1 to 4 with grain, 48% low glucosinolate RSM (5) or 48% SBM (6) both with starch. In numeric order of the groups 88, 85, 86, 84, 79 and 89% N were digested. Pigs responded to the additional faecal N excretion from RSM diets by a lower urinary N excretion and thus they reached the N-balance of the animals fed on SBM. In numeric order of the groups 86, 79, 80, 73, 73 and 92% of the organic matter of the solvent extracted meals were digested. In comparison with SBM even 48% RSM in the feed significantly lowered the digestibility of organic matter. Using detergents the additional faecal organic matter excretion of RSM versus SBM could quantified as two third lignin. In the case of 24% RSM in the diet--i.e. 15% of the carbohydrates given--the carbohydrate digestibility is estimated with a high error, that an energetic feed value should not calculated. Investigating 48% SBM or RSM respectively in a grain diet the net energy content was 9.8 MJ (666 Energetic Feed Units, EFU pig) or 8.3 MJ (569 EFU pig)/kg dry matter (DM). Based on the starch diet, however, little relevant for estimation of normal pig diets, there were evaluated 10.6 MJ (720 EFU pig) for SBM and 8.3 MJ (567 EFU pig) net energy/kg DM for RSM.

The influence of feeding fresh human milk supplemented either with EOPROTIN (n = 13) or human albumin (n = 15) on biochemical parameters and growth were studied in preterm infants with gestational ages below 32 weeks p.m. up to the 42nd day of postnatal life. In both feeding groups the intakes of protein, energy and electrolytes were similar. The serum concentrations of bile acids, alpha-amino-nitrogen and prealbumin, the renal excretion of total nitrogen, alpha-amino-nitrogen, urea and ammonia as well as the growth in weight and length were studied in all infants. The supplementation of the fresh human milk with EOPROTIN results in significant lower serum concentrations of alpha-amino-nitrogen (1.56 +/- 0.21 vs 2.03 +/- 0.27 mmol/l; p less than 0.01), higher serum concentrations of prealbumin (89.8 +/- 20.3 vs 72.7 +/- 13.3 mg/l; p less than 0.02), and lower urinary excretion of total nitrogen (7.4 +/- 0.9 vs 8.9 +/- 1.1 mmol/kg/day); if compared to the results found in the infants fed human albumin supplemented human milk. The higher nitrogen retention in the EOPROTIN than in the human albumin fed infants was associated by a significant higher growth in weight (16.6 +/- 1.4 vs 13.7 +/- 1.9 g/kg/day; p less than 0.01) as well as in length (1.02 +/- 0.08 vs 0.87 +/- 0.1 cm/week; p less than 0.01). The results indicate that the bioavailability of EOPROTIN is higher than that of human albumin. The observed differences in the nutritional response between the two human milk supplements may be based on differences in the amino acids composition which is in EOPROTIN adapted to the nutritional available part of the protein in human milk.

Wistar rats of a live weight of about 100 g were divided into 14 groups (5 animals/group). The rations given supplied the animals with 75%, 100% and 125% lysine, which brought about a moderate growth of the animals of approximately 2 g/animal and day achieved by limited feeding. The 3 lysine levels mentioned could be achieved by lysine supplements (L-lysine-HCl) for the following rations: barley (B), wheat (W), and wheat gluten (WG). For isolated soybean protein (assay protein) (S) the lysine levels 100% and 125% and for soybean meal (SM) the levels 116% and 125% could only be achieved. A control group with whole egg ration (W) (with its natural lysine content of 125% of the requirement) were also tested as comparison. During the 10-day period of the main experiment all 14 rations were supplemented with 0.5 g 15N-lysine (alpha amino group, 95% labelled with 15N). The N balance could only be significantly improved by lysine supplements in the rations B, W and SM with the lysine level of 125%. The biologic value of the protein sources was in rations B and WG also significantly improved by the highest lysine supplement. 15N excess (15N') from the deaminated 15N lysine was excreted with diet B rich in crude fibre mainly in faeces (more than 15% of the intake) and only about 10% in urine. With the diets without native crude fibre the excretion quota changed in favour of urine. The following 15N' amounts in per cent of 15N' intake from lysine were excreted in urine and faeces: B 75 = 31.3, B 100 = 30.9, B 125 = 28.0, W 75 = 24.3, W 100 = 32.2, W 125 = 32.6, GW 75 = 18.3, WG 100 = 24.2, WG 125 = 28.1, S 100 = 39.4, S 125 = 50.4, SM 116 = 34.9, SM 125 = 32.9, W 125 = 19.1. 15N excretion in urine and faeces increased in comparable relations in 6 cases of lysine increase levels only. Gross utilization of lysine can only conditionally be quantified by 15N labelled lysine supplement.

Investigations were carried out about nitrogen and energy metabolism feeding rations with 17-24 and 44-47% crude protein content on maintenance and growing level to castrated male hybrid pigs of line 150. In growing periods the N deposition amounted to 10 g/animal.d (15 kg live weight), 18 g/animal.d (30 kg LW) and 21 g/animal.d (greater than 40 kg LW) on lower protein feeding level. In experiments with higher protein feeding level the corresponding results were 17, 22 and 22 g N deposition/animal.d. The partial utilization of metabolizable energy for deposition amounted to 70% for the rations with 17-24% protein content and to 59% for the rations with 44-47% protein content, without correlation to the animals development and the alternation in the protein feeding level. The results of regression analysis about maintenance requirement were 814, 775 and 806 kJ metabolizable energy/kg LW0.62.d in trials feeding rations with 17-24% crude protein content as well as 764, 846 and 818 kJ metabolizable energy/kg LW0,62.d in trials feeding rations with 44-47% crude protein content. 1,5-1,8 MJ metabolizable energy were used per MJ protein energy deposition and 1,3-1,4 MJ per MJ fat energy deposition respectively. The energy deposition per kg live weight gain amounted to values between 9 (10 kg LW) and 18 MJ (60 kg LW).

The digestibility, the N balance, the rate of protein synthesis and other parameters, characterising the protein metabolism in dependence on live weight, protein- and energy supply are estimated on Wistar rats (4-5 animals/group). These experiments were done in 5 alternating consecutive growth and energy maintenance periods at 4 different levels of protein (6, 10, 17, 26% CP) during the live weight period of 70 to 230 g. The rate of protein synthesis was calculated from the course of renale 15N excretion by means of the end product method after giving a single dose of a mixture of 17 15N labelled amino acids. N deposition, rate of protein synthesis and flux rate increased with the protein level of the ration. During maintenance these data were much lower, but showed the same dependence on the protein level. The absolute protein synthesis (g/d) increased up to the live weight of 130... 180 g and decreased afterwards according to the age. The reutilization rate varied between 44 and 87% and decreased with increasing dietary protein level by 27% and during proceeding age by 8 ... 12%. In contrast to the absolute metabolism rates (g/d) the fractional rates (%/d) clearly decreased with the age of the animals. The stimulation of these rates by the dietary protein level resembled that for the absolute rates of synthesis. The protein deposition showed the typical course of a growing curve according to the N intake and the protein synthesis showed practically the same course but on a higher level. The break down remained constantly (approximately 140 mg N/d) up to an N intake of about 360 mg and afterwards it increased too.

Zinc speeds up a lot of metabolic processes because it is essential for a lot of enzymatic reactions. A modification of the zinc pool may influence the tumor growth. We used an animal model where we applied the Yoshida sarkoma intraperitoneally in its ascites form to parenterally fed Sprague-Dawley rats. Four groups with ten tumor bearing (TBR) and ten non-tumor-bearing rats (NTBR) each received different parenteral nutrition. The normocaloric Group 1 and the hypocaloric (reduced to 1/3 energy) Group 2 were fed without zinc. In Groups 3 (normocaloric) and (hypocaloric) high doses of zinc (0.519 mg/500 g Kg/d) were substituted. In Group 3 we found the quantitatively and qualitatively highest proof of tumor mass. The nitrogen content of the ascites wasn't significantly changed within the groups. We found a weight loss of the NTBR with zinc substitution. Zinc improves the synthesis of the tumor and leads to a weight loss of the host in our animal model.