Changes in body composition of neonatal piglets during growth

During studies of neonatal piglet growth it is important to be able to accurately assess changes in body composition. Previous studies have demonstrated that quantitative magnetic resonance (QMR) provides precise and accurate measurements of total body fat mass, lean mass and total body water in non-anesthetized piglets. The purpose of this study was to use EchoMRI-Infants’ instrument to measure changes in the body composition of piglets during growth from birth to about 12 kg. A total of 100 piglets were scanned several times starting at few days of age and weighting about 2 kg and finally weighting less than 12 kg. Each scan consisted of triplicate measurements. The rates of total body growth and fat and lean deposition were analyzed by linear regression analysis. The mean (SD) rate of total body growth was 23676 g/d (R2=0.980.04). The rate of fat deposition ranged from 10.6 to 64.9 g/d with a mean of 3213 g/d (R2=0.970.04). The rate of lean deposition ranged from 39.1 to 353.6 g/d with a mean of 18860 g/d (R2=0.950.10). The rates of both fat and lean deposition were highly correlated (P<0.001) with total body growth rate (r = 0.88 and 0.94, respectively). The correlation between the rates of fat and lean deposition was 0.74 (P<0.001). The results of this study demonstrate that QMR is a useful method for measuring changes in body composition in piglets. Furthermore, the results indicate that during the period of growth from birth to 12 kg, the rates of both fat and lean deposition are linear and highly correlated with total body growth.