In Vivo-Methods for Quantitative Measurement of Protein Deposition Rate in Animals with Emphasize on Swine

Most societal important breeding traits have an economic and a no economic value, and are sufficiently heritable for effective genetic selection. Genetic selection goals include the improvement of production traits, such as growth rate (g/day), meat percent, feed efficiency, and piglet production, because these traits are economically important. Because of their high relationship with the growth rate and feed efficiency, and the fact that they are inherently related with the animal health and welfare, the traits muscle lean gain - g/day and protein deposition rate g/day are useful measurements. Intensive pork production within large animal populations requires a special care to reduce the negative consequences of animal production on the environment. Growth models can be used to evaluate the nutrient content of the diets fed to minimize nutrient excretion. However, these models require the pigs compositional growth to be parameterized. The aim of this review is to compare different methods for in vivo quantitative estimation of protein deposition in pigs and other animals. The main criteria for the involving of in vivo methods for quantitative estimation of chemical body composition are: a) the accuracy of estimation; b) the financial costs and c) the possibilities for exploitation in field conditions. The chemical analysis post mortem is the most reliable, but it is also the most cost and labor - intensive method of estimation in cases of large numbers of animals. From statistical point of view, the best estimate of the accuracy of estimation respectively prediction equations of composition is the percentages RSD for percent substance. The D2O-dilution technique is relatively economical, since it allows the calculation of the composition of the empty body along with good opportunities for measurements under field conditions with high accuracy. The ultrasonic analysis has been shown to provide acceptable estimation of the protein deposition rate, where the two-dimensional B-mode scans (R2 = 0.36 –0.68) are superior to the one-dimensional A-scan gauges (R2 = 0.11 – 0.20). The bioelectrical impedance analysis supplies an accuracy of R2 = 0.81 for the estimation of the fat-free mass of a live animal. The magnet resonance tomography has been shown to accurate in the both, indirect (R2 = 0.89 - 0.97) and direct (R2 = 0.62) prediction of total body protein. The total body electromagnetic conductance TOBEC accurately predict fat-free lean and protein mass (R2 = 0.94), showing good prediction capacity, when used in line speeds in combination with growth modeling with optical probe. Corresponding to the stated criteria, the ultrasonic analysis, the bioelectrical impedance, and the D2O-dilution technique are the most economical and acceptability accurate methods that can be applied under field conditions. The MRT, the X-ray computer Thomography (R2 = 0.92 - 0.98), TOBEC, and the measurements of the isotope K40, are precise, but too expensive under the most conditions, since their implementation is possible only through specially instrumented equipment, only selection in nucleus farms.