In the past years several methods have been developed for the determination of the proportion of the nitrogen-containing substances of microbial origin passed from the rumen into the abomasum or the small intestine. Recently, on examining the D-amino acid content of foodstuffs, particularly milk and milk products, it has been observed that, in addition to D-Ala, Dglutamic acid (D-Glu) and D-aspartic acid (D-Asp) can also be detected in similar quantities, primarily in products which have links with bacterial activity. This gave rise to the idea of examining the diaminopimelic acid (DAPA), D-Glu and D-Asp content of bacteria extracted from the rumen of cattle and that of chyme from the same cattle, in order to determine the type of relation existing among these three components, and to establish whether D-Asp and D-Glu can be used in the estimation of protein of bacterial origin. On determination of the DAPA, D-Asp and D-Glu content by means of amino acid analyser and high performance liquid chromatography of duodenal chyme from five growing bulls and of ruminal bacteria from the same bulls, the following values were established. For chyme (and, in brackets, for ruminal bacteria) r value calculated by means of linear regression was 0.78 (0.76) between DAPA and D-Asp, and 0.70 (0.81) between DAPA and D-Glu. The r values between the crude protein content of ruminal bacteria and the markers examined were found to be the following: DAPA, 0.74; D-Asp, 0.73; D-Glu, 0.61. In the model experiment performed for the re-obtaining of values for protein of bacterial origin the theoretical values were determined on the basis of D-Asp and D-Glu and values approximately 10% higher than the theoretical value on the basis of DAPA. It is therefore recommended that in addition to DAPA these other two amino acids be included among the bacterial protein markers.

A follow-up study was performed to describe characteristic physiological alterations by means of computer tomography, direct chemical analysis and histology of the liver, and blood biochemical parameters during conventional force-feeding of Landes geese. 30 birds were exposed to an 18-day long force-feeding. Sampling was performed at the start and during force-feeding (7th, 11th, 14th, 18th days). Computer tomographic data were plotted in 3D histograms, effectively indicating the volumetric development and the fat deposition of the liver. Applying the so-called fat index, a saturation process was found for the hepatic fat content. Histological sections indicated the appearance of microvesicular fat forms in the hepatocyte cytoplasm, which first turned to a total fatty infiltration, later changing to a macrovesicular form with progressing inflammation; membrane damage was not visualized. In blood metabolites triglyceride, total and HDL cholesterol and uric acid increased measurably, while creatinine concentration decreased. Alanine aminotransferase, aspartate aminotransferase activities increased strongly, while that of lactate dehydrogenase only slightly. Based on the results of macroscopic and microscopic imaging techniques and blood biochemical parameters, a comprehensive follow-up study was performed, elucidating still unknown processes during force-feeding of geese.

Abstract. Non-invasive computerized tomography was performed on commercial broiler chickens, in both sexes, between 4 to 18 weeks of age, with the aim of body composition measurement. On the basis of 16–32 scans gathered from each bird during the scanning procedure, volumetric measurement of the breast muscle was performed. These values were at the 259; 493; 786 cm3 and 195; 460; 668 cm3 in male and female birds at the age of 6, 12 and 18 weeks, respectively. The total body fat content was characterized by the so called „fat index”, a value independent of the live weight. This indices were 7,3; 7,14; 9,48 and 8,8; 13,3; 21,6 following the above order. Total body fat and crude protein was determined both by CT and chemical analysis. The variables of the prediction equations were taken from the density values of the Hounsfield scale between −140 and +150, by summarizing the frequencies within each interval of 10 values. Several models were developed with Principal Component Analysis. The R² values of the estimations were high (R2 = 0,89; 0,88) for total body fat but moderate (R2 = 0,39; 0,44) in the prediction of crude protein content. The investigation of the tissue development in the body was carried out by means of 3D histograms.

Male and female BUT Big 6 and Bronze turkeys (type 1967) kept in a gene reserve were in vivo investigated with non-invasive high resolution computerized tomography by means of a sipral CT scanner. The imaging procedure was carried out at the ages of 5, 12, 16 and 21 weeks on two turkeys, in both sexes. All animals were kept under intensive conditions according to the demands of the conformation and the body weight of the relevant group average. On the basis of 30-50 scans gathered from each bird during the scanning procedure the volumetric measurement of the total body muscle content was performed. These values were at the 5 th week 0.9 and 0.8 vs. . The total body fat content was characterised by the so called "fat index", a value independent of the live weight. This indices were at the 21 st week: 0.12 and 0.20 vs. 0.12 and 0.13 following the above order. The investigation of the tissue development in the body was carried out by means of 3D histograms. The morphologic properties of the breast muscles were compared based on real 3D reconstructed images at the age of 21 weeks where the major differences concerned the m. pectoralis superficialis. The applied imaging methods are well applicable to describe the anatomic and body compositional differences in the excessively different genotypes.

-Commercial geese (Gray Landes) were examined by means of high-resolution spiral computer tomography in order to follow their liver development in vivo. Three ganders were scanned six times before, within and after a force-feeding period. 3D images of the liver were reconstructed from the 2D transverse slices with segmentation and rendering methods. The changes in the external surface, the volume of the liver and also the characteristic Hounsfield values were determined. The livers of another 70 ganders were examined by CT, then by direct chemical analysis (days 0, 13, 18, 19, 20 and 21 of force-feeding). To estimate the chemical composition of the tissue, prediction equations were developed based on the pixel frequency distributions. With partial least squares (PLS) regression, the ether extract and crude protein content could be estimated with R 2 = 0.97 and R 2 = 0.96 accuracy, respectively. Data analysis was complemented with serial blood serum measurements characteristic of liver steatosis. The method applied may be a unique possibility to study the real geometrical relations of liver development and also to describe the qualitative changes of tissue composition during the force-feeding period in vivo, with special regards to selection purposes. goose liver / computerized tomography / liver yield / liver composition Résumé -Études in vivo du développement du foie d'oie par tomographie. Le développement du foie des oies (Landaise grise) a été examiné « in vivo » par tomographie spirale à haute résolution (CT). Les coupes ont été préparées sur six jours différents, avant, pendant et après le gavage, sur trois jars. Les images en trois dimensions (3D) ont été reconstituées à partir des images en 2D, par l'ajustement selon la méthode d'ajustement par segments. La modification de la surface externe et du volume du foie ont été définies par les valeurs Hounsfield. Outre les foies des trois jars, 70 jars ont été encore examinés par la même méthode (CT), ensuite des analyses chimiques directes ont été réalisées aux jours 0, 13, 18, 19, 20 et 21 du gavage. La composition chimique du foie a été estimée par la création d'équations de régression en fonction de la division de fréquence des pixels. A l'aide d'équations des moindres carrés la teneur en graisse et en protéines du foie ont été prédites avec une bonne précision (R 2 = 0,97 et 0,90, respectivement). L'analyse du développement de la stéatose hépatique a été complétée par la mesure des caractéristiques sanguines. La méthode de tomographie « in vivo » donne la possibilité unique de caractériser les corrélations géométriques réelles au cours du développement du foie et de décrire les modifications qualitatives dans la composition du tissu pendant l'engraissement par gavage. Cette méthode pourrait être utilisée en sélection.foie gras / oie / tomographie / rendement / composition