Prediction of tissular body composition from protein and lipid deposition in growing pigs1

Tissular and chemical body composition were measured for 85 pigs that were serially slaughtered between 15 and 110 kg BW and considered lean (boars from a Synthetic Line and the Piétrain breed), conventional (boars, gilts, and barrows from the Large White breed), or obese (Meishan barrows). These six groups were expected to be quite different with regard to their body composition. Tissular body composition was predicted from chemical body composition, according to nonlinear regression models. Common relationships were obtained for lean and conventional pigs (Group effect: P > .05). Empty body weight and the weight of adipose tissues were predicted directly from the amounts of body protein and lipid, whereas for estimation of weights of carcass, muscle, and lean, the prediction was improved when the weight of offals (visceral organs and blood) was also included in the model. Validation of prediction models on literature data indicated good agreement between calculated and measured values (R2 > .90). These relationships were not applicable to Meishan barrows. In pig growth modeling approaches, proposed equations can be used in order to predict the tissular composition of body weight gain and commercial value at slaughter.