E Borgmann’s scientific contributions

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%).

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.

Die scheinbare präzäkale Nährstoffverdaulichkeit und Aminosäuren (AS)-Resorption von 10 Rationen wurden bei Schweinen mit End-zu-Seit-Ilcorcktal-Anastomosen (IRA) und mit Ilcozäkal-Brückenfisteln (IZB) bestimmt. Folgende Rationen kamen zur Anwendung: Lupinen (zwei Arten) + Gerste (1., 2.), Lupinen (zwei Arten) + proteinfreies Futter (3., 4.), Ackerbohnen (zwei Arten) + proteinfreies Futter (5., 6.), “Canola” + proteinfreies Futter (7.), zwei Mischungen aus Weizen + Gerste + Fischmehl (8., 9.) und Gerste + Lysin (10.). Bei IRA-Schweinen war die scheinbare Verdaulichkeit (sV %) der Organischen Substanz und der Rohkohlenhydrate lediglich in der 4. und 5. bzw. der 1., 4. und 5. Ration signifikant höher also bei IZB-Schweinen. Die sV % des Rohproteins und des Rohfettes war in allen Rationen für beide Tiergruppen praktisch gleich.Von den insgesamt 180 AS-Resorptionsvergleichen zeigten nur 20 (d.h. 11%) Unterschiede, die größer als 5%-Einheiten waren. Die Resorptionsraten einiger AS waren bei den IRA- niedriger als bei den IZB-Schweinen und bei einigen anderen AS war es umgekehrt. Die Methioninresorption der Leguminosenrationen (1, 2, 3, 5, 6) und der Gersteration (10) war bei IRA-Tieren um bis zu 14,8% -bzw. um 4%-Einheiten niedriger ausgefallen. Als Ursache werden mikrobiclle Aktivitäten (Netto-Methionin-Synthese) insbesondere im Rektalstau der IRA-Tiere angenommen, die bei Aufnahme der geringen Mengen an proteingebundenem Methionin der Leguminosenrationen die Resorptionswerte verfälschen. Um diesen Fehler zu minimieren, wird die End-zu-End-Anastomose vorgeschlagen. Die Unterschiede in der scheinbaren AS-Resorption zwischen IRA- und IZB-Schweinen sind teilweise mit den aufgezeigten unterschiedlich hohen Ausscheidungen an endogenen AS zu erklären.COMPARISON OF THE PRECAECAL NUTRIENT DIGESTIBILITY AND AMINO ACID ABSORPTION BETWEEN PIGS WITH ILEO-RECTAL ANASTOMOSES AND ILEO-CAECAL RE-ENTRANT CANNULAEThe 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.

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.

Für die Durchführung der mobilen Beuteltechnik (MBT), die zur Ermittlung der präzäkalen und Gesamt-Rohproteinverdaulichkeit und Aminosäurenresorption (Lysin, Methionin, Zystin, Threonin, Tryptophan) bei 10 Einzelfuttermitteln (Ackerbohne, Lupine, Rapsextraktionsschrot, Fischmehl, Gerste, Weizen) und 3 Rationen zur Anwendung kam, wurden jeweils 2 weibliche ileorektostomierte sowie intakte Schweine mit einfachen Duodenalkanülen benutzt. Je Versuchsfutter und Tier kamen 36 Polyamidbeutel zum Einsatz. Nach peptischer Vorverdauung in vitro, Applikation durch die Duodenalkanüle und Passage durch den Darmtrakt wurden die im Beutel verbliebenen Rückstände für jedes Tier und Futtermittel zu einer Sammelprobe vereinigt und diese wie das Ausgangsmaterial auf Trockensubstanz, Stickstoff und Aminosäuren analysiert. Die direkt ermittelten Verdaulichkeiten (BV) und über regressive Berechnung erhaltenen Werte (BVb) wurden mit den in konventionellen Verdauungsversuchen bestimmten scheinbaren Verdaulichkeiten (sV) verglichen. 74% aller BV-Daten waren höher als die entsprechenden scheinbaren Verdaulichkeiten. Die Gegenüberstellung von BV und sV ergab bei 58%, die von BVb und sV nur noch bei 17% Abweichungen von > ± 4 Verdaulichkeitseinheiten. Mit Additivitätsrechnung wurde bei Rationen überprüft, ob die über die BV der Einzelkompo-nenten berechnete BV einer Ration zum gleichen Ergebnis führt, wie die direkt für die Mischung bestimmte. Dabei traten teilweise gegenläufige Resultate auf. Daraus wird die Schlußfolgerung gezogen, daß die Anwendung der MBT bei Mischfutterrationen durch weitere Untersuchungen überprüft werden muß; bei Einzelfuttermitteln kann sie jedoch nach regressiver Verrechnung der Ergebnisse zur schnellen und vereinfachten Verdaulichkeitsermittlung genutzt werden. INVESTIGATIONS INTO THE USE OF THE MOBILE BAG TECHNIQUE IN PIGS 1. Estimation of the apparent crude protein digestibility and amino acid absorption of feedstuffs and diets 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.

In einer Versuchsserie mit je 2 ileorektostomierten Schweinen wurden nach der mobilen Beuteltechnik für sieben ¹⁵N-markierte Futtermittel präzäkale scheinbare und wahre Rohproteinverdaulichkeiten ermittelt. Die nach der Isotopenverdünnungsmethode berechneten wahren Proteinverdaulichkeitswerte Iagen je nach Futtermittel 4–14 Einheiten über den scheinbaren Verdaulichkeitswerten, da diese durch die Infiltration des Beutelrückstandes mit endogenem unmarkierten N beeinflußt werden. Der endogene N-Anteil im Beutelrückstand betrug 25–70% des Gesamt-N in Abhängigkeit vom geprüften Futtermittel. Er wird außerdem durch tierindividuelle Unterschiede (im Mittel 4–7%) verändert und durch das Abspülen der Beutel nach der Darmpassage — im Vergleich zu abgetrockneten Beuteln — um 3–10% gesenkt. INVESTIGATIONS INTO THE USE OF THE MOBILE BAG TECHNIQUE IN PIGS 2. Estimation of apparent and true crude protein digestibilities of ¹⁵N-labelled feedstuffs 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%).

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%.

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.