Protein, fat, and bone mineral deposition rates in growing pigs (birth to 90 kg) of different RyR1 genotypes studied by dual energy x-ray absorptiometry

摘要

A growth study was performed from birth to 90 kg live body weight (BW) using dual energy x-ray absorptiometry (DXA) as a non-invasive tool to measure the deposition rates of main body components protein (lean), fat, and bone mineral in different ryanodine receptor 1 (RyRl) "model" genotypes (NN —> "fat", Nn —> intermediate, nn —> lean). The pigs were scanned at 10, 30, 60, and 90 kg BW. Fat and bone mineral measurements were used directly, while the lean mass was used to calculate protein mass (protein deposition rate — Pd) using a device specific regression equation based on chemical reference data. Pd increases steadily up to about 50 kg body weight (Pd_(max) -140 g/d for nn) and then gradually declines. The amount of daily protein and fat deposition depends on the body composition/ genetic background (metabolic situation) while observing nearly identical total tissue deposition rates for the three genotypes over time. At the end of the growth period studied (60-90 kg BW), the leanest genotype (nn) has a faster decreasing Pd than the less lean ("intermediate" -