Über die Exaktheit von Stickstoffbilanzen bei langfristigen Stoffwechselversuchen

Abstract

The N-retention calculated by balance experiments should, theoretically, be identical with the results obtained by chemical analysis of the animals. Experimental comparisons of both methods being reported in the literature are contradictory. To scrutinize this problem measurements of N-retention were conducted with 22 pigs by continuous balance experiments from 20-40 kg LW up to 110 kg LW (n = 16) or up to 160 kg LW (n = 6), respectively. At the end of the experimental period the animals were slaughtered and the N-content was determined quantitatively by chemical analysis of the whole bodies of the pigs. To calculate the N-content of the pigs at the beginning of the balance experiments 19 pigs were slaughtered and analysed quantitatively at 25 kg LW (n = 11) and 40 kg LW (n = 8), respectively. In all animals N deposits as determined by slaughter investigations were less as compared to balance experiments, the differences amounting to 6.7% of the calculated N-retention being equivalent to 93.3% analytical recovering of the N-retention as measured in balance experiments. The differences between both methods increased slightly with longer duration of the experiments resulting in 6.2% and 8.1% with the pigs of 110 kg and 160 kg final live weight, respectively. The differences must be regarded as being caused by accumulation of small errors completely coinciding into the same direction. Thus a certain overestimation of N-deposits by balance experiments might be looked at as being unavoidable irrespective considering any meticulous care in conducting the experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of feeding level upon protein and fat deposition in Iberian heavy pigs

“…It is widely accepted that the slaughter procedure leads to more reliable results (Quiniou et al, 1995a). Differences in the range of 5.8% to 16.7% with respect to the slaughter procedure have been observed (Just et al, 1982;Oslage et al, 1987;Noblet et al, 1987;Verstegen et al, 1993;Quiniou et al, 1995a). The discrepancies found in the present experiment (2.6%-9.5%) fall within this range.…”

Untersuchung zum Vergleich des Bilanzverfahrens und der Tierkörperanalyse zur Messung des Protein‐, Energie‐ und Mineralstoffansatzes von Aufzuchtferkeln1

“…Die Arbeitsgruppe um HENNIG fand im vergleichenden Versuch bei Schweinen zwischen 35 bis 110 kg LM Differenzen in der Gro-Genordnung von 15-30% zwischen beiden Verfahren, wobei die Bilanz die hoheren Werte ergab. OSLAGE et al (1987) verglichen den N-Ansatz im Bilanzversuch und der Korperanalyse bei 22 Schweinen zwischen 25 bis 160 kg LM. Hierbei ergab sich eine mittlere Differenz beider Verfahren von 6,7% bei einer Variation zwischen 2,6 bis 10,8%, wobei die N-Bilanz die hoheren Ansatzwerte ergab.…”

“…erbrachten eine recht befriedigende Ubereinstimmung beider Methoden", ohne dai3 jedoch vergleichende Einzeldaten genannt werden. In einer neueren Veroffentlichung von OSLAGE et al (1987) iiber Schweine zwischen 25-160 kg wird von einer Uberschatzung des N-Ansatzes mit der Bilanzmethode gegeniiber der Korperanalyse im Bereich von 2,6% bis 10,8% berichtet. Neuere vergleichende Untersuchungen bei Aufzuchtferkeln liegen nicht vor.…”