Nutritional level and energetic source are determinants of elevated circulatory lipohydroperoxide concentration.

Dietary energetic impact on oxidative stress is incompletely understood. Therefore, effects of diets on oxidative stress were studied using a crossover block design. In Expt 1, intake of metabolizable energy (ME) was restricted or ad libitum. In Expt 2, isoenergetic and isonitrogenic diets were fed, replacing carbohydrate energy by energy of fatty acids. Circulatory lipohydroperoxides (LOOH), markers of acute oxidative stress, were expressed absolutely and in terms of cholesterol or TAG levels. In Expt 1, plasma (jugularis vein) LOOH was assayed in combination with whole-body oxidative metabolism using gas exchange and heart rate (HR) during feeding periods and at rest. In Expt 2, LOOH was assayed in plasma from portal and a large udder vein and a mesenteric artery. In Expt 1, intake increased VO2, HR and LOOH following overnight fast with higher values (P < 0.05) when feeding ME ad libitum. Intake of ME ad libitum (3 weeks) increased cardiac protein of cytochrome oxidase and endothelial-type nitric oxide synthase (P < 0.05), indicating adaptation of the heart to higher activity. Transient HR responses evoked by an antidiabetic drug (levcromakalim) revealed a linear positive correlation with relative LOOH (r2 0.79), supporting the relationship between oxidative metabolic rate and lipoperoxidation. Evidence for exogenous lipids as LOOH source provided the vessel-specific rise in LOOH through replacing carbohydrate ME by lipid ME (Expt 2). Thus, dietary energy level and energetic source are important for circulatory LOOH with a role of vascular activity in production of oxidant.

Measurements of heat production for estimation of maintenance energy requirements of Hereford steers.

This study aimed to test the hypothesis that maintenance energy requirement (MEm) can be estimated from continuous heat production measurements during a change from a near maintenance feeding level to far below maintenance for two consecutive days. The MEm of eight Hereford steers weighing 286 +/- 5 kg (mean +/- SE) was determined in a balance trial. In addition, during the 10-d collection period, the animals were kept in open-circuit respiration chambers to measure 24-h gas exchange continuously at 10-min intervals. During the balance trial, the animals were fed dried chopped grass twice daily at an estimated level of 1.2 x MEm. After termination of the collection period on the 11th d of the balance trial, the steers were offered 2 kg/d of wheat straw while only gas exchange was measured. Estimates of MEm were derived from heat production (HP) data. The analyses included values of 24-h HP, HP of the nocturnal period (0000 to 0630), HP of the nocturnal period (excluding HP caused by standing) during the grass-feeding period and 24-h HP, nocturnal HP, and nocturnal HP (excluding HP caused by standing) during the straw feeding period. The MEm predicted from estimates of HP measurements were 536 +/- 9, 470 +/- 8, 441 +/- 8, 435 +/- 8, 393 +/- 9, and 373 +/- 9 kJ.kg of BW(-0.75).d(-1), respectively, whereas MEm calculated from data of the balance trial were 416 +/- 9 kJ.kg of BW(-0.75).d(-1). Values predicted for nocturnal HP (excluding HP caused by standing) of grass fed animals, 24-h HP, and nocturnal HP during straw feeding did not differ significantly from MEm. The differences in MEm among animals were reflected by all estimates of HP, whereas the correlation with the 24-h HP during straw feeding reached 0.9 (P = 0.002). We conclude that the method described is adequate to determine MEm with a sufficient degree of accuracy.

Carbon and nitrogen content based estimation of the fat content of animal carcasses in various species.

The objective of this study was to explore whether the C and N content can be used to estimate the fat content of animal carcasses. Considering the mean C and N contents of body fat and body protein, the fat content (EE) [%] can be predicted from C and N values [%] according to the generally valid equation EE = 1.3038 x C - 4.237 N. The application of this equation to estimate the total fat content of all animal carcasses results in significant differences in fat content between predicted and measured values. Therefore, we derived specific equations for rats, pigs, cattle, sheep, broilers and mice to predict the fat content by dual linear regression analysis (y = EE [% DM], x1 = C [% DM], x2 = N [% DM]) based on measured fat, C, and N contents of animal body samples. The specific equations for different animals showed residual standard deviations of 1.55, 1.63, 1.12, 1.35, 1.85 and 0.92% fat for rats, pigs, cattle, sheep, broilers and mice, respectively.

Effect of a soy protein diet on protein and energy metabolism and organ development in protein-restricted growing pigs.

Two feeding experiments were carried out with castrated male pigs weighing between 10 and 30 kg to study acute and persisting dietary effects on growth and on protein and energy metabolism in growing pigs. Pigs were fed semi-synthetic isoenergetic and isonitrogenous diets at 50% protein requirement with either soy protein isolate (SPI) or casein (CAS) as sole protein source. Intake of protein and ME amounted to 9% w/w and 1800 kJ x kg BW (-0.62) x d(-1) in Exp. 1, respectively, and 9% w/w and 1430 kJ x kg BW(-0.62) x d(-1) in Exp. 2. The CAS diet was supplemented by Lys, Met, Thr and Trp. In Exp. 1 (acute effects), 18 pigs received the CAS diet for 24 days (period 1); 9 pigs were then switched to a SPI diet whereas 9 pigs continued on the CAS diet for another 31 days (period 2). In Exp. 2, a third period of 31 days was added in which the SPI group was switched back to CAS diet. The control group was fed on the CAS diet throughout Exp. 2 (86 days). Altogether the majority of parameters were not affected neither comparing SPI with CAS in Exp. 1 nor inspecting possible persistence of effects in Exp. 2. In detail, in Exp. 1 SPI compared to CAS feeding resulted in a lower efficiency of protein utilisation and lower protein retention. Attendant upon the lower protein retention an increased energy retention as fat was only observed in tendency. SPI feeding caused a decreased body weight, thyroid weight and increased hepatic carbohydrate content that persisted after the diet was changed back to CAS (Exp. 2).

Effects of protozoa on methane production in rumen and hindgut of calves around time of weaning.

Effects of the presence or absence of ciliate protozoa on methanogenesis in the rumen and hindgut were investigated in young calves during a 7-week period. Ten Holstein calves, aged 7 days, were divided in two groups (n = 5) and fed an increasing amount of a commercial milk replacer and small amounts of a calves starter. One group was inoculated with ciliate fauna on two occasions, week 5 and 6, while the second remained ciliate-free. The absence of protozoa in the rumen decreased rumen empty weight (-23%, P < 0.01), and rumen pool size of N (-36%, P < 0.01) and crude fat (-37%, P < 0.05). Rumen bacteria of non-faunated calves contained a higher proportion of total amino acid-N per 16 g N (+3%, P < 0.01) and D-alanine-N per 16 g N (+13%, P < 0.05) compared to faunated calves. Further results contain a reference for a higher bacterial mass in the ciliate-free rumen with an increased number of bacteria adherent to rumen mucosa. The CH4 production in the rumen increased exponentially with the increase in protozoa population size (R2 = 0.68). In presence of 46 x 10(4) protozoa per ml rumen fluid, the in vitro CH4 production of rumen fluid per mol total VFA was about 34% higher in faunated than in non-faunated calves (P < 0.001). Hydrogen (2H) recovery of rumen fermentation was positively correlated (R2 = 0.55) to the CH4 production rate. Methanogens were attached on rumen mucosa. Methanogenesis, induced by rumen mucosa attached bacteria, was stimulated by ruminal protozoa. In the absence of protozoa in the rumen, the acetate-propionate ratio and butyrate proportion of VFA were reduced. In vivo, in the absence of protozoa not only the whole animal CH4 production (-30%, P < 0.05) but also the digestibility of carbohydrates (-4%, P < 0.05) was reduced. Thereby no difference was observed in the intake of ME per kg DM between the groups. In conclusion, the methanogenesis in the rumen, but not in hindgut, is associated with the development of the ruminal protozoa population. The level of methanogenesis (mol/mol VFA) in the hindgut amounts to 20% of the ruminal methanogenesis.

Energy metabolism of cocks and broiler chickens fed on diets with different carbohydrate sources.

Energy balances of cocks and chickens were measured using the nitrogen-carbon-balance method. In Experiment 1 twelve adult White Leghorn cocks were fed alternately on a basal ration or on a supplemental ration composed of 75% basal diet and 25% carbohydrate source as a supplement. In Experiment 2 six groups of 12 male broiler chickens were fed successively on two diets each with different carbohydrate sources (40% of DM) and on two energy levels. The investigated carbohydrate sources were glucose, fructose, sucrose, maize starch, raw and steamed potato starch, dried sugar beet pulp, tapioca, wheat, maize, rye and barley. In both experiments the energy digestibility of the diets with raw potato starch, beet pulp and barley was significantly lower compared to the other diets. Digestibility of those ranged from 88 to 81%. By simple linear regression no significant differences in efficiency of utilisation of ME of the diets between the carbohydrate sources sugars, starches and cereal grains could be proved. The corresponding MEm values agreed very close among the diets (411 to 429 kJ.kg BW-0.75.d-1).

Research note: is starch utilization for fat deposition in man different from that in animals?

Utilization of starch for fat deposition in humans was investigated by means of the nitrogen-carbon-balance method in a respiration chamber using the difference principle with a basal and a supplemental period. The basal diet was designed to maintain an adequate energy balance of the volunteer and to meet the maintenance requirements of protein, minerals and vitamins. The dietary fat content was minimized to 2.7% of DM. The digestibility of starch energy was determined to be 97%. The estimated efficiency of ME utilization of starch for energy deposition in humans amounted to 75.8%, which was in accordance with former results in pigs and rats. This suggests that in case of an intake of diets rich in carbohydrates and low in fat the utilization of carbohydrates for lipogenesis in humans is similar to that in monogastric mammal animals.

Cellular aspects of the regulation of metabolic rate.

Beyond the energy requirement of maintenance, the assimilated energy, occurring in bioproducts, is linearly proportional to the intake of metabolizable energy in non-underfed conditions. In contrast, resting metabolic rate is differing between individuals within a population of an animal species. As adaptability to changed environmental conditions may play a role, young bulls were exposed to thermoneutral (18 degrees C) and low (4 degrees C) ambient temperatures and were fed at two feeding levels (1.0 and 1.6 times energy requirement in maintenance) to produce metabolic rate differences, using the same animals, metabolic rate was altered by reducing the sympathetic outflow in each case. Expression of sulfonylurea receptors in circulating mononuclear leukocytes and cells from skeletal muscle (m. semitendinosus) was studied by flow cytometry. Changes of metabolic rate at rest corresponded to the portion of cells with sulfonylurea receptors expression. The data from reducing the sympathetic outflow and those from sulfonylurea receptors expression are useful to explain metabolic rate differences among individuals of an animal population.

Expression of sulphonylurea receptors in bovine monocytes from animals with a different metabolic rate.

The aim of this study was to investigate the relationship between expression of sulphonylurea receptors (SUR) and metabolic rate (MR). SUR on monocytes and cells from muscle tissue were detected using fluorescent glibenclamide and flow cytometry. Transmembrane potential differences were detected by oxonol dye fluorescence measurements. A bovine model was used to induce differences in the MR by exposure to different ambient temperatures (4 degrees C and 18 degrees C), by different feeding levels (1.0- and 1.6-fold the metabolizable energy requirement for maintenance) and by alpha2-adrenergic stimulation. We found that cells from skeletal muscle (m. semimembranosus), immunochemically identified as smooth muscle cells, skeletal muscle fibres and monocytes, responded in comparable fashions to glibenclamide and ATP, i.e. with a depolarization, and to cromakalim with a polarization, suggesting that monocytes are useful indicators of regulatory events occurring in muscle cells. Glibenclamide fluorescence was assumed to represent SUR associated with KATP channels. Significant differences were detected in the percentage of depolarized monocytes in the different variants of the model. A linear correlation between monocytes that bound fluorescent glibenclamide and the MR was evident (with a coefficient of determination of 0.94) and was reproducible following reduction of the MR, by alpha2-adrenergic stimulation, suggesting that expression is involved in the regulation of whole-body energy expenditure.

Calorimetric validation of 13C bicarbonate and doubly labeled water method for determining the energy expenditure in goats.

The purpose of the present study was to validate the 13C bicarbonate method (13C-M) and the doubly labeled water method (DLWM) for the estimation of the CO2 production R(CO2) in goats as a ruminant model. Indirect calorimetry was chosen as the reference method. Studies were carried out in 2 male African dwarf goats at 3 different developing stages (age: 5, 10, and 14 months, body mass: 14.6, 20.3, and 21.7 kg). Animals were fed a balanced feed 14 days before and during the studies. The isotope tracers (4 mg/kg NaH13CO3, 120 mg/kg 2H2O, and 75 mg/kg H218O; 99 AT.-%) were simultaneously given as a single pulse injection into the jugular vein. Thereafter, the animals were kept for 8 days in two respiration chambers (volume of chamber: 2.85 m3, air flow rate: 25 1/min) for the estimation of CO2 production and O2 consumption. For the determination of R(CO2) using the 13C-M samples of exhaled breath were drawn from the respiration chambers. The 13C enrichment and CO2 concentration of breath samples were measured by means of an infrared isotope analyzer. In order to determine R(CO2) by means of the DLWM, blood serum was used. The 2H and 18O enrichments were measured by an isotope ratio mass spectrometer. Urine samples were collected over 24 h to quantify renal water losses. The R(CO2) was calculated by means of the 13C-M using the area under the 13C enrichment-time curve. The determination of R(CO2) by means of the DLWM was based on the slopes of the 2H and 18O disappearance curves and the body water pool obtained from the zero time intercept of the isotope curves. The values of R(CO2) resulting from the 13C-M were found to be comparable with those from the calorimetric measurement. Smaller (not statistically significant) values of R(CO2)--92% from 13C-M and 87% from DLWM--compared to the indirect calorimetry could indicate the incorporation of 13C and 2H into metabolites other than CO2 and H2O, respectively. The body water contents calculated from the zero time intercepts of the 2H and 18O disappearance curves amounted to 66% and 63%, respectively. The body water content was found to be not related to the age of animals. The renal water loss was calculated to be 35% of the total water loss (0.76 l/d.

Effect of body composition, feed intake, and ambient temperature on heat production of Vietnamese Sway-back pigs.

From theoretical considerations animals with a higher protein-fat ratio in the body should have a higher maintenance energy requirement (MEm). The literature on this problem shows a non-uniform picture with deviating results. From the results of a series of experiments it is possible to compare the heat production (HP) of male and female animals of the Vietnamese Sway-back breed pigs which vary quite widely in their body composition. The protein-fat ratio was 1.2 for the male and 0.2 for the female animals. In the experiments 4 male and 4 female animals in the live weight range of 20-33 kg and 33-42 kg, respectively, were involved. The HP measurements were carried out in climatized respiration chambers on two levels of energy intake at ambient temperatures of 6 degrees C, 12 degrees C, 18 degrees C, 24 degrees C, 30 degrees C, and 35 degrees C. The dependence of HP on the ambient temperature has been described by a cubic regression function. Thermoneutral temperatures are lower in the female animals caused by the better insulation effect of the backfat. The difference in HP which was expected by the large difference in body composition, was not found. The absolute protein mass determined the correlation to HP. Certainly the difference increased after lowering the ambient temperature. The influence of different factors on HP is discussed.

Involvement of alpha 2-adrenergic activities in thermogenic responses to feeding, feeding level, and ambient temperature.

To investigate the alpha 2-adrenergic effect on the metabolic rate, young bulls were exposed to environmental variants (feeding levels of 1.0 and 1.6 times the MEm and ambient temperatures of 18 degrees C and 4 degrees C) and treated preprandially with a alpha 2-adrenergic agonist (clonidine) in each case. The heat production (HP) was continuously measured by indirect calorimetry using climatized respiratory chambers. Post-clonidine, the preprandial HP fell in all variants but the strongest decrease occurred at 4 degrees C, 1.6 times the MEm. The postprandial HP rose 1.3-fold the HP of animals received the carrier (saline) at 4 degrees C, 1.6 times the MEm. Animals exposed to 18 degrees C, 1.6-fold the MEm did not significantly increase the postprandial HP after clonidine administration, suggesting different sympathetic outflow corresponded to differing resting metabolic rate, occurring in the environmental variants. Circulating fuels (glucose, non-esterified fatty acids) responded to alpha 2-adrenergic reduction of the sympathetic outflow but did not parallel the HP changes. Studies on monocytes revealed a linear correlation (r2 > 0.9) between resting metabolic rate and expression of sulfonylurea receptors, the constitutive component of ATP-sensitive K+ channels (KATP) suggesting a function of KATP in coupling the systemic HP with cellular metabolism.

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 6. Comparative studies of energy and nitrogen metabolism of non-pregnant and pregnant sows]. / Untersuchungen zum Energie- und Stickstoffumsatz von Graviden und Laktierenden Sauen Sowie von Saugferkeln. 6. Mitteilung--Vergleichende Energie- und Stickstoffumsatzmessungen an güsten und graviden Sauen.

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.

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 7. Energy and nitrogen metabolism in suckling piglets]. / Untersuchungen zum Energie- und Stickstoffumsatz von graviden und laktierenden Sauen sowie fon Saugferkeln. 7. Mitteilung--Energie und Stickstoffumsatz von Saugferkeln.

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).

[Results from measurements of nitrogen and energy metabolism in adaptive different cattle]. / Ergebnisse aus Stickstoff- und Energieumsatzmessungen an adaptiv differenten Rindern.

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.

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 5. Energy and nitrogen metabolism of pregnant sows]. / Untersuchungen zum Energie- und Stickstoffumsatz von graviden und laktierenden Sauen sowie von Saugferkeln. 5. Mitteilung--Energie- und Stickstoffumsatz von graviden Sauen.

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.

[Effect of the convertibility of energy (Q) on energy maintenance requirement and utilization and convertible energy for the assessment of ruminants. 1. Digestibility of energy and nutrients]. / Einfluss der Umsetzbarkeit der Energie (q) auf den Energieerhaltungsbedarf und die Verwertung der umsetzbaren Energie für Ansatz bei Wiederkäuern. 1. Mitteilung--Verdaulichkeit von Energie und Nährstoffen.

The energy metabolism was measured by means of indirect calorimetry in growing bulls with mean live weights of 290-420 kg and in wethers with mean live weights of 40-60 kg. The animals were fed 12 (bulls) and 8 rations (wethers) with high variation in the nutrients composition and with a range of energy metabolizability (q) between 0.74 and 0.47 on 3 steps of nutrition level (deposition, maintenance, underfeeding) as a rule. The energy digestibility of the 12 rations tested in growing bulls on the nutrition level maintenance was measured between 81.9 and 56.4% and that of the 8 rations tested in wethers was measured between 82.6 and 55.6%. On the high and middle nutrition levels the data of energy and nutrients digestibility in growing bulls and wethers were in good agreement, except the significant lower digestibility of crude protein in cattle. On the low nutrition level digestibility of energy, crude protein, crude cellulose and N free residual substances in wethers was 3-5 digestibility units lower than in bulls. The increase of nutrition level by 1 unit lowered the energy digestibility in bulls by 4.2 and the nutrients digestibility about 4-8%-units (0.7 for starch). In sheep the effect was not so high as in cattle. There were differences in the rumen physiological parameters between the animal species. In the growing bulls' rumen liquid the part of acetate was higher and the parts of propionate and butyrate were lower. The content of NH3 was higher in sheep. The increase of nutrition level caused higher amounts of volatile fatty acids in the two animal species with lowering the part of acetic acid and raising the parts of propionic and butyric acid.

[Effect of the convertibility of energy (Q) on energy maintenance requirement and utilization and convertible energy for the assessment of ruminants. 2. Energy maintenance requirements and energy utilization]. / Einfluss der Umsetzbarkeit der Energie (q) auf den Energieerhaltungsbedarf und die Verwertung der umsetzbaren Energie für Ansatz bei Wiederkäuern. 2. Mitteilung--Energieerhaltungsbedarf und Energieverwertung.

In growing bulls (290-420 kg LW) and wethers (40-60 kg LW) the energy metabolism was measured by means of indirect calorimetry on 3 steps of energy intake (deposition, maintenance, underfeeding) as a rule with feeding 12 (growing bulls) resp. 8 rations (wethers) with a range of energy metabolizability (q) between 0.74 and 0.47. Investigations were carried out in oxen previously with 9 rations with a range of q between 0.65 and 0.56 were completed by measurements of the energy metabolism with underfeeding and also analysed for the influence of q on energy maintenance requirement and energy utilization. In all 3 animal categories the energy maintenance requirement was not dependent on q significantly. On the nutrition level maintenance the mean energy maintenance requirement amounted to 467 +/- 64 in growing bulls (n = 104), 533 +/- 53 in oxen (n = 44) and 323 +/- 59 kJ ME/kg LW0.75.d in wethers (n = 32). The partial utilization of the metabolizable energy for deposition was influenced significantly (alpha = 0.05) by q in growing bulls only (kpf = -0.1495 + 0.9933q +/- 0.050). A differentiation of the utilization of metabolizable energy for deposition was demonstrable in wethers only with mean values of 50.7% (kf) and of 64.2% (km); km was also independent on q.

[Energy and nitrogen metabolism of pregnant and lactating sows in addition to the suckling piglets. 4. Chemical composition and energy content of the conception products, reproductive organs and the live weight gain or loss in pregnant or lactating sows]. / Untersuchungen zum Energie- und Stickstoffumsatz von graviden und laktierenden Sauen sowie von Saugferkeln. 4. Mitteilung--Chemische Zusammensetzung und Energiegehalt der Konzeptionsprodukte, der reproduktiven Organe und der Lebendmassezunahmen oder -abnahmen bei graviden und laktierenden Sauen.

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.