The influence of protein nutrition in early life on growth and development of the pig. 1. Effects on growth performance and body composition.

The effects of feeding either a high-protein (HP) diet or a low-protein (LP) diet between 1.8 and 15 kg live weight (LW) and a low-energy (LE) or a high-energy (HE) intake but at the same protein intake subsequent to 15 kg LW on the performance and body composition of pigs growing to 75 kg LW were investigated. During the LW period 1.8-15 kg, pigs given the LP diet exhibited poorer growth performance (P less than 0.01) and at 15 kg contained more fat (P less than 0.01) in their empty bodies than pigs given the HP diet. On the LE treatment subsequent to 15 kg LW, pigs previously given the LP diet deposited protein at a faster rate and exhibited more rapid and efficient growth to 60 kg LW than those given the HP diet before 15 kg. However, on the HE treatment, pigs previously given the LP diet deposited protein at a slower rate and exhibited poorer growth performance (P less than 0.05) between 15 and 45 kg LW but grew at a faster rate between 45 and 60 kg LW than pigs previously given the HP diet. On the LE treatment subsequent to 15 kg LW the differences in body composition between the two protein groups were no longer significant at 45 kg. However, on the HE treatment, pigs previously given the LP diet remained fatter (P less than 0.05) to 60 kg LW than those previously given the HP diet. The results suggested that restricting protein intake between 1.8 and 15 kg LW reduced, temporarily, the upper limit of protein retention and growth performance during subsequent development. This finding is discussed in relation to the effects of protein nutrition in early life on the hyperplasic development of muscle tissue.