Diarrhea is one of the main problems for pigs during the post-weaning period. Traditionally, antibiotic growth promoters have been used to control post-weaning diarrhea, but consumers are increasingly concerned about this practice and there is therefore an interest in feeding diets that contain no antibiotics. However, feeding pigs without antibiotic growth promoters requires alternative strategies to control post-weaning diarrhea, but feeding low protein diets may be one way to reduce the incidence of post-weaning diarrhea. However, there is a lack of knowledge about consequences of reducing the protein level in diets fed to weanling pigs.

Feeding low protein diets to pigs results in increased net energy in the diet, reduced water intake by pigs, and reduced nitrogen excretion. This will result in reduced volume of manure and also reduced concentrations of ammonium in manure. However, if formulation of low protein diets results in feeding diets with concentrations of indispensable AA that are below the requirements, deposition of protein in pigs may be greater and deposition of fat may be increased compared with pigs fed a diet containing higher level of protein. However, it is not known if feeding a diet low in protein to weanling pigs also results in changes in carcass characteristics of market pigs.

Therefore, the objective of this experiment was to test the hypothesis that feeding a low-protein diet to pigs during the post-weaning period will result in reduced diarrhea during this period, but no effects on growth performance from wean to finish and no changes in carcass composition of pigs when they reach market weight.