Estimation of body composition of pigs

A study was conducted to evaluate the use of deuterium oxide (D2O) for in vivo estimation of body composition of diverse types of pigs. Obese (Ob, 30) and contemporary Hampshire X Yorkshire (C, 30) types of pigs used in the study were managed and fed under typical management regimens. Indwelling catheters were placed in a jugular vein of 6 Ob and 6 C pigs at 4, 8, 12, 18 and 24 wk of age. The D2O was infused (.5 g/kg body weight) as a .9% NaCl solution into the jugular catheter. Blood samples were taken immediately before and at .25, 1, 4, 8, 12, 24 and 48 h after the D2O infusion and D2O concentration in blood water was determined. Pigs were subsequently killed by euthanasia injection. Contents of the gastrointestinal tract were removed and the empty body was then frozen and later ground and sampled for subsequent analyses. Ground body tissue samples were analyzed for water, fat, N, fat-free organic matter and ash. Pig type, age and the type X age interaction were significant sources of variation in live weight, D2O pool size and all empty body components, as well as all fat-free empty body components. Relationships between age and live weight or weight of empty body components, and between live weight, empty body weight, empty body water or D2O space and weight of empty components were highly significant but influenced, in most cases, by pig type. The results of this study suggested that, although relationships between D2O space and body component weights were highly significant, they were influenced by pig type and were little better than live weight for the estimation of body composition.