Whole body amino acid composition of the growing pig

Abstract

Abstract The protein in the whole bodies of 76 Landrace × Large White entire male and female pigs fed different diets (different combinations of protein and non‐protein energy intake) for 0, 4, 6 or 8 weeks from 12 kg liveweight, were analysed for their amino acid composition. The purpose was to see if the composition changed in any systematic way with body protein weight. It was found that there were some effects of dietary treatment and sex on the concentrations of some amino acids, but these effects were exerted through their effects on protein weight. The concentrations, in the protein, of lysine and histidine increased significantly ( P <0.01), whereas cystine concentration decreased significantly ( P <0.001) with increasing protein weight. These changes were consistent with the assumption that there is a change in the proportion of total body protein as hair protein with increasing body protein weight, since lysine and histidine are present in relatively high proportions in the body (excluding hair) of the pigs, whereas cystine is present in particularly high concentrations in the hair. The concentration of an amino acid in the body of the pig could thus be expressed as a function of body protein weight; this allows for changes in the amino acid concentrations of the body protein as the animal increases in size.