RESUMEN
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.
Asunto(s)
Composición Corporal , Regulación de la Temperatura Corporal , Ingestión de Energía , Metabolismo Energético , Porcinos/fisiología , Temperatura , Animales , Calorimetría Indirecta , Femenino , Masculino , Caracteres SexualesRESUMEN
With 294 feedstuffs-classified into 22 feedstuff categories-, from which in the original literature besides the crude protein (CP) and lysine (lys) contents their precaecal (pc) and partly their total (t) digestibilities in pigs had been presented, assessments of the pc and t apparent digestibilities (AD%) were done by two different ways. Between the prediction possibility using the mean value of nondigestible CP resp. lys (mean ndCP, means ndlys, g/kg DM) and the usual way of calculating average digestive coefficients (mean ADCP%, mean ADlys%) there were with regard to the validity of predictions only small differences, with the tendency of partly more advantageous results by the first cited procedure. Good assessments of pc ADCP% and pc ADlys%, where 70 ... 100 per cent of the single feedstuffs showed prediction errors of only < or = 5 digestibility units, were got for the protein concentrates field bean, lupin, soybean meal, sunflower seed meal, rapeseed meal, yeast and casein as well as with some restrictions for sorghum, linseed meal, blood meal and poultry by-product meal. Less reliable and connected with more uncertainties are the pc digestibility predictions for cereals, peas, cottonseed meals, meat (& bone) meals and fish meals: only 20 ... 30 per cent of the single feedstuffs showed good appraisals with differences < or = 5 digestibility units. In the rule t digestibilities can be assessed more exactly than pc digestibilities, for lys these predictions are mostly less precise than for CP.
Asunto(s)
Proteínas en la Dieta/metabolismo , Digestión , Absorción Intestinal , Lisina/farmacocinética , Porcinos/fisiología , Alimentación Animal , Animales , Porcinos/metabolismoRESUMEN
Five pigs were each surgically prepared with end-to-side (E.t.S.) and end-to-end (E.t.E.) ileorectal anastomoses (IRA). The ileo-caecal valve was preserved in both modifications. The animals were fed diets with maize or solvent extracted oil seed meals from sunflower, cottonseed, linseed or soybean and maize in combination with one of these oil seed meals. The aim of the experiment was to estimate the influence of both IRA-techniques on the precaecal nutrient digestibility and amino acid (AA) absorption. The crude carbohydrate digestibility in two of the five single protein diets and in three of the four blends were significantly higher in the E.t.S.--than in the E.t.E.--IRA group. There were no significant differences between the two IRA-modifications in crude protein (CP) and crude fat digestibility. No differences were observed in AA absorption for the single components maize, sunflower- and cottonseed meal. The absorption values of isoleucine, leucine and valine from linseed meal were significantly more than 5%-units higher in the E.t.S.-group than in E.t.E.-animals. There were similar results in soybean meal for four essential AA but with differences below 5%-units. Accordingly the two IRA-modifications did not influence the AA absorption to a practically important extent.
Asunto(s)
Alimentación Animal , Digestión , Intestino Delgado/fisiología , Porcinos/fisiología , Aminoácidos/farmacocinética , Anastomosis Quirúrgica/veterinaria , Animales , Aceite de Semillas de Algodón , Carbohidratos de la Dieta/farmacocinética , Grasas de la Dieta/farmacocinética , Proteínas en la Dieta/farmacocinética , Femenino , Helianthus , Íleon/cirugía , Absorción Intestinal , Intestino Delgado/metabolismo , Aceite de Linaza , Recto/cirugía , Semillas , Glycine max , Zea maysRESUMEN
In a series of experiments in two ileo-rectostomized pigs the precaecal apparent and true digestibilities for crude protein of seven 15N-labelled feedstuffs were studied using the mobile bag technique. True digestibility values of crude protein calculated with the help of isotope dilution were 4-14 units higher than the corresponding apparent digestibility values. This is caused by the infiltration of the bag residues with endogenous unlabelled nitrogen. In dependence on the kind of feedstuff the endogenous N portion in the bags amounted to 25-70% of the total N. In addition, the contamination is influenced by differences between the animals (mean 4-7%) and by different treatments of bags after gut passage (3-10%).
Asunto(s)
Alimentación Animal , Proteínas en la Dieta/metabolismo , Digestión , Porcinos/fisiología , Animales , Isótopos de NitrógenoRESUMEN
The apparent precaecal nutrient digestibility and amino acid (a.a.) absorption of 10 diets were estimated in pigs with end-to-side ileorectal anastomoses (IRA) as well as with ileocaecal re-entrant cannulae (IZB). The digestibilities of organic matter and crude carbohydrates were significantly higher in IRA pigs than in IZB pigs in two resp. three diets only. There were no practical important differences for the digestibilities of crude protein and crude fat in all diets. Out of the 180 a.a. absorption comparisons only 20 (i.e. 11%) showed differences larger than 5%-units. The absorption rates of several a.a. were lower in IRA than in IZB pigs and of some other a.a. on the contrary. The methionine absorption of five legume diets and one barley + lysine diet were up to 15% resp. 4%-units lower in IRA pigs. Possibly this was due to the activity of microbes in the rectum in connection with a small intake level of protein bound methionine. In order to minimize such a falsification it is proposed to use the end-to-end anastomosis. The deviations in the apparent a.a. absorption between IRA and IZB pigs can be explained partly by differences in the quantity of precaecally excreted endogenous a.a. per 100 g DM intake.
Asunto(s)
Aminoácidos/metabolismo , Digestión , Porcinos/fisiología , Anastomosis Quirúrgica , Alimentación Animal , Animales , Cateterismo , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/metabolismo , Proteínas en la Dieta/metabolismo , Femenino , Absorción Intestinal , Porcinos/metabolismoRESUMEN
The mobile bag technique (MBT) was used in two ileorectostomized and two intact pigs with duodenal cannulae, in order to estimate the precaecal and total crude protein digestibility and amino acid (lysine, methionine, cystine, threonine, tryptophan) absorption of ten single feedstuffs (field bean, lupin, rapeseed meal, fish meal, barley, wheat) and three diets. For each feed 36 bags were applied per animal. After a peptic predigestion in vitro, application of the bags through the duodenal cannula into the intestine and their passage through the gut, the residues remaining in the bags were pooled to collective samples and just as the original feed material analysed on dry matter, nitrogen and amino acids. The directly determined MBT-digestibilities (BV) and the values obtained by regressive calculations (BVb) have been compared with apparent digestibilities (sV) conducted from conventional digestion experiments. 74 per cent of all BV data was higher than the corresponding sV values. Similarities of BV with sV showed in 58 per cent, those of BVb with sV only in 17 per cent. In all cases differences of > +/- 4 digestibility units showed. Checking additivity of diet-BV by means of calculations from the BV of their single ingredients did not generally lead to the same results as the directly estimated diet-BV; in some cases the results were contrary. Therefore the use of MBT for mixed feed diets has to be further investigated. For single feedstuffs the MBT can be used successfully as a rapid and simple technique when regressive calculations are employed.
Asunto(s)
Aminoácidos/metabolismo , Digestión , Porcinos/fisiología , Aminoácidos/análisis , Alimentación Animal/análisis , Animales , Proteínas en la Dieta/metabolismo , Femenino , Absorción IntestinalRESUMEN
In faeces and ileal digesta samples of 31 intact (INT) as well as 73 surgically differently prepared pigs bacterial fractionations and 2.6-diaminopimelic acid (DAP) estimations were carried out in order to calculate the bacterial N proportion in faeces N and digesta N after feeding various diets. Because of a high individual variability and the analytical variation width of the DAP/N-ratios no distinct influences of the fed diets could be found. The average DAP/N-values in the faeces (0.224) of INT pigs ranged in the same magnitude as in the digesta (0.0272) of ileorectostomized (IRA) pigs with open colon descendens (IRAo), where a digesta backflow is possible. Distinct lower DAP/N-ratios (0.0125 resp. 0.0043), however, were found in the digesta of pigs with ileo-caecal cannulae (IZB) or IRA pigs with closed colon (IRAg). On the base of various premises (N of the "bacterial fraction" C is only bacterial N; the DAP found in fraction A originates from intestinal bacteria adhering to feed particles) conducted calculations of the bacterial N proportions (in per cent of total N) led to the following data: Faeces of INT pigs: 43.0 ... 68.2 vs. 69.6 ... 89.0; digesta of operated pigs (except protein free diet) IRAo: 22.3 ... 57.0 vs. 46.2 ... 73.8; IZB: 17.0 ... 35.7 vs. 25.2 ... 53.6; IRAg (only 3 pigs): 23.6 vs. 24.2. The proportion of bacterial N in the digesta N of protein free fed IRAo pigs was 22.0 vs. 22.6%.
Asunto(s)
Bacterias/metabolismo , Heces/química , Íleon/química , Nitrógeno/análisis , Porcinos/microbiología , Alimentación Animal , Animales , Ácido Diaminopimélico/análisis , Contenido Digestivo/química , Íleon/microbiologíaRESUMEN
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.
Asunto(s)
Peso Corporal , Proteínas en la Dieta/administración & dosificación , Metabolismo Energético , Proteínas/metabolismo , Aminoácidos/administración & dosificación , Alimentación Animal , Animales , Digestión , Ingestión de Energía , Cinética , Masculino , Nitrógeno/metabolismo , Biosíntesis de Proteínas , Ratas , Ratas EndogámicasRESUMEN
Energy metabolism-by means of indirect calorimetry-and kinetic parameters of the protein metabolism on the basis of the 3-compartment model were measured with 4 groups of 4 or 5 male Wistar rats in the growth range of between 70 and 230 g live weight in a total of 5 alternately successive periods at the feeding levels growth and energy maintenance as well as 4 different levels of protein supply (6, 10, 17 and 26% crude protein in the feed). The partial energy requirement values for protein retention (bp) for every animal and every period are calculated from the data of energy metabolism. On an average of the 3 growth periods they amounted to 1.75 +/- 0.37 kJ/kJ. A statistically significant linear relation with a slope of approximately 1 could be derived regressively between the protein synthesis rate and the protein retention rate, including all 5 test periods. There was no proven relation between the bp values and the corresponding individual values of the ratio of protein synthesis rate-diminished by the regressively derived protein synthesis rate in the N balance-to the protein retention rate. The results do not permit proven statements on the quantitative relations between protein turnover and energy requirement for protein retention, which is first of all due to methodical shortcomings in measuring both protein metabolism and energy metabolism. They indicate, however, that the heat production from protein synthesis has only a relatively low share in the additional energy expenditure for protein retention and does not considerably surpass the necessary minimal cost for the synthesis of the deposited protein in growing rats.
Asunto(s)
Proteínas en la Dieta/administración & dosificación , Metabolismo Energético , Proteínas/metabolismo , Alimentación Animal , Animales , Regulación de la Temperatura Corporal , Calorimetría , Cinética , Masculino , Biosíntesis de Proteínas , Ratas , Ratas Endogámicas , Análisis de RegresiónRESUMEN
A method is described for estimation of 2.6-diaminopimelic acid (DAP) using an automated amino acid analyzer and MOORE and STEIN ninhydrin reagent. Investigations were made concerning the influence of sample treatment on DAP content of faeces and ileal digesta of pigs and isolated bacteria. Oxidation before hydrolysis did not change DAP content of faeces and bacterial samples, but increased DAP of digesta. Since analytical reasons were excluded, different accessibility of DAP in faeces and digesta for hydrolysis is suggested. Lyophilization or preservation of fresh samples with formaldehyde and phenolic solution, resp., resulted in no significant influence on DAP content.
Asunto(s)
Bacterias/química , Ácido Diaminopimélico/análisis , Heces/química , Contenido Digestivo/química , Porcinos/fisiología , Animales , Hidrólisis , Íleon , Oxidación-ReducciónRESUMEN
Rations with dried feedstuffs and rations with between 30 and 50% raw potatoes in the dry matter as well as steamed potatoes and sugar beets, sucrose and apple pectin were tested in measurings of the total metabolism in growing pigs with ileo-rectal anastomoses. The prececal digestibility of the energy of the rations ranged between 42% (rations with raw potatoes) and 79% (rations with sucrose). The digestibility of the rations with a 50% quota of steamed potatoes was better by 30%--units than that of rations with raw potatoes. In addition to crude nutrient digestibility, data are given on the digestibility of starch, water soluble carbohydrates and pectin. The wide variation in the N retention of 6-25 g/animal.day can only be partly connected with energy retention. Urine energy amounted to between 2.5 and 5% of gross energy. The average utilization of metabolizable energy amounted to 69.4%. A connection is to be seen with the value of energy maintenance requirement of 646 kJ retention energy/kg LW0.62.d.
Asunto(s)
Alimentación Animal , Carbohidratos de la Dieta/metabolismo , Metabolismo Energético , Porcinos/metabolismo , Anastomosis Quirúrgica/veterinaria , Animales , Digestión , Femenino , Íleon/cirugía , Metano/metabolismo , Nitrógeno/metabolismo , Pectinas/metabolismo , Recto/cirugía , Solanum tuberosum , Sacarosa/metabolismo , Porcinos/cirugía , Orina/químicaRESUMEN
Results of the measuring of the total metabolism of growing intact pigs (INT) and pigs with ileorectal anastomoses (IRA) are compared. The 16 comparisons are based on studies with rations of dried feedstuffs and rations containing between 30 and 50% of the DM raw or steamed potatoes and sugar beets, sucrose and apple pectin. On an average of all comparisons the relative values for the digestibility of energy, DM and the organic matter as well as for the metabolizability of the energy were between 81 and 82% (values measured at INT animals = 100). The comparison also refers to the crude nutrients, the water-soluble carbohydrates, the starch and the pectin. As a tendency, the IRA utilized the metabolizable energy better than the INT animals. The energy maintenance requirement of the IRA animals was--by 15%--significantly higher than that of the INT animals. There is not yet an answer to the question in how far comparative studies of INT and IRA animals make verified statements with regard to the differences in the energetic utilization of the precaecally and postileally digested nutrients possible. For this, further experiments will be necessary.
Asunto(s)
Alimentación Animal , Carbohidratos de la Dieta/metabolismo , Metabolismo Energético , Porcinos/metabolismo , Anastomosis Quirúrgica/veterinaria , Animales , Digestión , Femenino , Íleon/cirugía , Pectinas/metabolismo , Recto/cirugía , Solanum tuberosum , Sacarosa/metabolismo , Porcinos/cirugíaRESUMEN
The apparent precaecal crude protein digestibility and amino acid absorption as well as the total digestibility of the nutrients organic matter, crude protein, crude fat and crude carbohydrates were determined of rations consisting of barley plus oilmeals of two rapeseed varieties of double quality (DQ) from Canada (Canola) and the GDR as well as of one variety of single quality (SQ) with 10 female pigs weighing between 120 and 140 kg with ileorectal anastomoses (IRA) and 4 intact (INT) female pigs weighing between 150 and 160 kg. The three rapeseed meals (RSM) were furthermore fed to IRA pigs as sole protein source together with protein-free feed. Based on the digestibilities of the crude nutrients determined with INT pigs and calculated with the difference method the energy content of RSM DQ "Canola", DQ GDR and SQ GDR could be calculated as 495, 633 and 500 EFUpig/kg DM (average: 543 EFUpig). The precaecal digestibility of the crude protein of the above mentioned RSM sorts determined with IRA pigs and calculated with the difference method amounts to 73, 76 and 75% resp. and is thus lower than the average absorption of all amino acids. The precaecal digestibilities of crude protein and essential amino acids for the mixtures calculated from the digestibility values of the individual feedstuffs barley and the above mentioned RSM largely agree with the experimentally determined digestibility values, i.e. there is additivity. On an average of the values known from literature for DQ RSM (including our own results), the precaecal digestibility of crude protein amounts to 70, of lysine to 74, of methionine to 82, of cystine to 82, of threonine to 69, of tryptophan to 72 and of isoleucine to 74%.
Asunto(s)
Aminoácidos/metabolismo , Brassica , Proteínas en la Dieta/metabolismo , Digestión , Porcinos/metabolismo , Anastomosis Quirúrgica/veterinaria , Alimentación Animal , Animales , Femenino , Hordeum , Íleon/cirugía , Recto/cirugía , Porcinos/cirugíaRESUMEN
In vitro determination of protein digestibility by treating feedstuffs with pepsin-HCl yields results that differ considerably from the precaecal protein digestibility figures. Comparable results were received when the largest polypeptides in the solution obtained after peptic und tryptic treatment were precipitated with CuSO4 + NaOH.
Asunto(s)
Alimentación Animal , Proteínas en la Dieta/metabolismo , Digestión , Pepsina A/farmacología , Porcinos/metabolismo , Animales , Femenino , Técnicas In Vitro , Solubilidad , Tripsina/farmacologíaRESUMEN
As part of digestibility and energy metabolism studies in intact and ileorectostomized growing pigs model experiments were carried out on sampling techniques and the influence of storage conditions on CO2 and volatile fatty acid production in chyme. Results on the formation of CO2 and VFA in chyme and faeces are given. They indicate that chyme from the small intestine can be subjected to bacterial and enzymatic changes outside the animals and therefore must be stored in a cool place. In the chyme of IRA animals with closed colon descendens (end-to-end anastomosis) significantly reduced VFA contents were found in comparison to animals with open colon descendens (end-to-side anastomosis).
Asunto(s)
Dióxido de Carbono/metabolismo , Ácidos Grasos Volátiles/metabolismo , Heces/química , Contenido Digestivo/química , Porcinos/metabolismo , Anastomosis Quirúrgica , Animales , Bacterias/metabolismo , Digestión , Metabolismo Energético , Heces/enzimología , Heces/microbiología , Fermentación , Contenido Digestivo/enzimología , Contenido Digestivo/microbiología , Íleon/cirugía , Preservación Biológica , Recto/cirugíaRESUMEN
The apparent precaecal (pc) digestibility of crude protein (CP) and the apparent pc absorption of the key amino acids (AA) lysine, methionine, cystine, isoleucine, threonine and tryptophan from two yellow sweet lupine (L. luteus) varieties (Bornova, Borluta) and one narrow-leafed sweet lupine (L. angustifolius) were determined with ileorectostomized pigs. When the influence of the basal diet (barley or protein free rations) was checked with regard to absorption there were significant differences in a few cases only. In comparison to soybean meal (SBM) the methionine of the lupines was significantly worse, the cystine significantly better absorbed. The CP and the other key AA of the lupines showed approximately the same or even slightly higher pc absorption than those of SBM. With the example of the pc-absorbable AA amounts it was shown that sweet lupines with an approximately equally high CP content as in SBM cannot completely substitute the latter even after lysine and methionine supplementation because the absorbable tryptophan is by far insufficient, and isoleucine and threonine make up only 75% in comparison to SBM. On the basis of the content of pc-digestible CP and pc-absorbable AA it becomes possible to substitute high-grade imported protein concentrates according to their ability of AA supply in the feeding of pigs completely or partly by home-made protein feeds.
Asunto(s)
Aminoácidos/metabolismo , Alimentación Animal , Proteínas en la Dieta/metabolismo , Fabaceae , Plantas Medicinales , Porcinos/metabolismo , Animales , Digestión , Femenino , Absorción Intestinal , Glycine maxRESUMEN
In an experiment with 3 pigs (initial live weight 30 kg, each fitted with 2 re-entrant fistulas in duodenum and ileum, one labelled with 15N), the duodenal and ileum digesta was exchanged. The N and 15N contents were estimated in faeces, urine, duodenal and ileum digesta of all experimental animals as well as in special organs and in the contents of different tract sections. The 15N excess (15N') of N compounds secreted into the gut lumen was determined using the 15N' in pancreas, gut mucosa and TCA-soluble blood serum. From measuring the digesta passage through the 3 sections of the digestive tract: 1. mouth ... duodenum, 2. duodenum ... ileum, 3. ileum ... after (Krawielitzki et al., 1989) the absorption and secretion rates of nitrogen were calculated. Secretion into the 1st section amounted to 5.3 g N/d (= 15% of intake) and the absorption to approximately 1% of intake. In the 2nd section the corresponding dates were 8.9 resp. 38.6 g N/d (= 25 resp. 110% of N intake), and in the 3rd one 1.9 resp. 8.4 g N/d (= 5.6 resp. 24% of N intake). Total absorption amounted to 134% of N intake and the over all re-absorption of endogenous N compounds secreted into the gut lumen to about 90%. During the passage the amount of endogenous N (g/d) decreased from 5.3 at the duodenum to 3.8 at the ileum to 1.6 in the faeces, but the relative portion increased (13 resp. 35 resp. 39%). An incorporation into body proteins occurred only from N compounds absorbed in the 1st and in the 2nd section. N (or 15N) absorbed in the large intestine was almost quantitatively excreted by urine. The method of digesta exchange between cannulated labelled and unlabelled pigs seems to be a suitable method to estimate absorption and secretion of exogenous and endogenous N portions in various sections of the digestive tract.
Asunto(s)
Duodeno/metabolismo , Íleon/metabolismo , Absorción Intestinal , Nitrógeno/metabolismo , Porcinos/metabolismo , Animales , Ingestión de Líquidos , Ingestión de Alimentos , Heces/análisis , Masculino , Nitrógeno/análisis , Nitrógeno/orina , Distribución TisularRESUMEN
Described in this paper are ileocecal cannulation and ileorectostomy, two methods used for quantitative collection of chyme in the context of protein assessment on the basis of prececally absorbable amino acids. Reference is made to the manufacture of new, flexible intestinal cannulas of biocompatible material and to the surgical approaches in connection with either method. Determination of prececal digestibility of crude nutrients and absorption of amino acids in three rations fed to pigs with ileorectal anastomoses and ileocecal cannulas gave identical data or fair agreement with the extension of two amino acids. The conclusion was drawn that data recorded by means of the two methods can be used in the preparation of tabulated values.
Asunto(s)
Aminoácidos/metabolismo , Cateterismo/veterinaria , Proteínas en la Dieta/metabolismo , Digestión , Porcinos/metabolismo , Absorción , Animales , Ileostomía/veterinariaRESUMEN
In a difference experiment the apparent precaecal (pc) and total intestinal (tot) nutrient digestibility and amino acid (AA) absorption of 5 yeasts (n-alkane yeasts Fermosin and Paprin, molasses/molasses distillers residue yeast, two sulfite waste liquor yeasts) were studied. The two n-alkane yeasts were very highly digested pc, the difference to tot digestibility is only small in most cases. In contrast to this, the pc and tot digestibility values of molasses/molasses distillers residue yeast differed considerably more. The probable reason for this is too hot drying due to which pc digestibility, particularly of the crude protein, and pc AA absorption are considerably reduced. In the two sulfite waste liquor yeasts, sulfite waste liquor residues containing lignin impair especially the crude carbohydrate digestibility and the energetic feed value; the better processing conditions of origin A, however, reduced considerably the negative effects. The results confirm that each yeast origin has its specific particularities, which have to be taken into consideration when they are used in feeding.
Asunto(s)
Alimentación Animal , Digestión , Absorción Intestinal , Porcinos/metabolismo , Levadura Seca/metabolismo , Aminoácidos/metabolismo , Animales , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/metabolismo , Proteínas en la Dieta/metabolismo , Metabolismo Energético , Femenino , Masculino , MelazaRESUMEN
Methodical recommendations are suggested--predominantly for laboratory and small animals (rats and young chickens)--for the determination of parameters of the protein metabolism of the whole body after single doses of a mixture of 15N labelled amino acids by means of the determination of the temporal course of cumulative 15N excretion in urine and the assessment of the tracer kinetic data in a compartment model. These recommendations are to make it possible to carry out purposefully such experiments under comparable conditions. The advantages of this method are: the non-invasive character of the method; the possibility of repeating the experiment with the same animal; the adaptability to other methods of investigation (e.g. measuring energy metabolism); the relatively low expenditure of labour and requirement of test animals; the relatively good reproducibility of the method. Thus this method is a good supplement to the flooding and permanent infusion methods and should be used wherever the determination of parameters of the protein metabolism of the total body is sufficient.