The performance and body composition of growing pigs during protein or energy deficiency and subsequent realimentation

Seventy-eight 15 kg Polish Landrace gilts were allocated to three feeding regimens (C, E, P). Up to 25 kg the C pigs (control) were fed 95% of ad libitum intake; the group E pigs consumed 40% less energy, while group P animals received 40% less protein compared with group C. From 25 to 70 kg all of the pigs were fed diets differing in energy density (L - 12.4 MJ ME; 11 - 13.2 MJ ME) at restricted feeding (R) or ad libitum (A) levels. Animals were slaughtered at 25 kg (n=12) and 70 kg (n=66) and their bodies were analyzed for physical and chemical composition. From 15 to 25 kg the P and E pigs grew slower than controls (367, 242 vs 513 g/day). At 25 kg the P pigs had 185 g fat and 142 g protein per kilogram empty body, and entrail weight similar to C pigs. The E pigs had 90 g fat and 163 g protein per kilogram empty body and their entrails were 12% smaller compared with group C and P pigs. From 25 to 70 kg the average daily gain of pigs as well as their physical and chemical body composition at 70 kg did not depend on previous feeding. However, the rate of recovery of particular chemical body components depended on feeding intensity as well as on the previous feeding regimen. It was found that the compensatory response of pigs took about 2-3 weeks and previously underfed pigs are able to fully compensate their anatomical and chemical body composition.