In vivo body composition in autochthonous and conventional pig breeding groups by dual-energy X-ray absorptiometry and magnetic resonance imaging under special consideration of Cerdo Ibérico

Abstract

The improvement of carcass quality is one of the main breeding goals in pig production. To select appropriate breeding animals, it is of major concern to exactly and reliably analyze the body composition in vivo. Therefore, the objective of the study was to examine whether the combination of dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) offers the opportunity to reliably analyze quantitative and qualitative body composition characteristics of different pig breeding groups in vivo. In this study, a total of 77 pigs were studied by DXA and MRI at an average age of 154 days. The pigs originated from different autochthonous or conventional breeds or crossbreeds and were grouped into six breed types: Cerdo Ibé rico (Ib); Duroc 3 Ib (Du_Ib); White Sow Lines (WSL, including German Landrace and German Large White); Hampshire/Pietrain (Pi_Ha, including Hampshire, Pietrain 3 Hampshire (PiHa) and Pietrain 3 PiHa); Pietrain/Duroc (Pi_Du, including Pietrain 3 Duroc (PiDu) and Pietrain 3 PiDu); crossbred WSL (PiDu_WSL, including Pietrain 3 WSL and PiDu 3 WSL). A whole-body scan was performed by DXA with a GE Lunar DPX-IQ in order to measure the amount and percentage of fat tissue (FM; %FM), lean tissue (LM; %LM) and bone mineral, whereas a Siemens Magnetom Open with a large body coil was used for MRI in the thorax region between 13th and 14th vertebrae in order to measure the area of the loin (LA) and the above back fat area (FA) of both body sides. A GLM procedure using SAS 9.2 was used to analyze the data. As expected, the native breed Ib followed by Du_Ib crossbreeds showed the highest %FM (27.2%, 25.0%) combined with the smallest LA (46.2 cm 2 , 73.6 cm 2 ), whereas Ib had the lowest BW at an average age of 154 days. Pigs with Pi_Ha origin presented the least %FM (12.4%) and largest LA (99.5 cm 2 ). The WSL and PiDu_WSL showed an intermediate body composition. Therefore, it could be concluded that DXA and MRI and especially their combination are very suitable methods to reliably identify differences in body composition and carcass traits among different pig lines in vivo.

Use of dual-energy x-ray absorptiometry in non-ruminant nutrition research

“…Other methods such as CT and MRI can also be used for whole-animal evaluation (Font i Furnols and Gispert, 2009;Barchia et al, 2010;Clarys et al, 2010;Kovner et al, 2010), but these methods are slow, expensive, and complex. However, the latter two technologies can be used to create methodologies for evaluating parts of the body to obtain an estimate for the whole animal (Kremer et al, 2012a;Kremer et al, 2012b). The purpose of this paper was to describe the use of DXA in non-ruminant nutrition research, highlighting some differences between DXA and the reference methods and identifying the advantages and disadvantages of this technology.…”

Use of magnetic resonance imaging to predict the body composition of pigs in vivo

“…The detailed results and statistical differences of the DXA and MRI measurements especially for the different genotype groups are provided and discussed in a study by Kremer et al (2012).…”

“…Therefore, by using only one device and software mode, the present study used DXA as quantitative in vivo analysis reference technique to evaluate the potential of MRI as in vivo imaging technique for predicting body composition in live pigs. The pigs originated from different extensive or conventional breeds and their crosses, such as Cerdo Iberico or German Landrace, German Large White, Hampshire, Duroc and Pié train, representing a wide range of body composition as described in a study by Kremer et al (2012). First of all, the coefficients of determination and error estimates between the MRI-derived muscle or fat areas and the DXA-derived tissue masses or proportions were evaluated by linear regression and an additional PLS analysis.…”

“…In this study -similar to the related study by Kremer et al (2012), 77 pigs (seven boars, 33 barrows and 37 gilts) were examined for their in vivo body composition by using MRI and DXA. The pigs originated from different extensive or conventional breeds or crossbreds: Cerdo Iberico (n 5 5), Duroc 3 Cerdo Iberico (n 5 15), German Landrace and German Large White 5 White Sow Lines (n 5 8), Hampshire and Piétrain 3 Hampshire and Pié train 3 Pié train-Hampshire (n 5 6), Pié -train 3 Duroc and Pié train 3 Pié train-Duroc (n 5 24) and Pié train or Pié train-Duroc 3 White Sow Lines (n 5 19).…”

“…The muscle and fat areas were calculated using the image analysis software Dicom Works 1.3.5 (Inviweb, Lyon, France). The corresponding regions of interest for both body sides were defined manually after visually distinguishing between muscle and fat by qualified personnel as described in Kremer et al (2012).…”