Amino acid requirements of growing-finishing pigs with a different health status E. Kampman-van de Hoek Department of Animal Nutrition, Wageningen UR Livestock Research, P.O. Box 65, 8200 AB Lelystad, The Netherlands Animal Nutrition Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands A compromised health status of pigs results in immune system activation. In turn, amino acids (AA) are repartitioned from skeletal muscle deposition towards the immune system (Humphrey and Klasing, 2004). The objective of this project is to quantify effects of health status on AA requirements of pigs. To determine the effect of health status and dietary AA supply on protein deposition and AA metabolism of growing pigs, barrows (n=28) of similar age (55 ± 0.4 d of age) and genotype were selected from a low (LH) or high (HH) health status farm. Within the HH and LH group, pigs were allocated to a diet adequate (ADEQ) or deficient (DEF) in AA supply. Immunologic parameters were determined in blood, a 4-d nitrogen balance was performed, and AA metabolism was studied by infusing a mixture of 13
C-AA followed by frequent blood collection. A greater degree of immune system activation
in LH pigs was observed. DM and N digestibility was lower in LH than HL pigs, while the efficiency of digestible N utilization was higher in LH. Especially LH-ADEQ pigs showed compensatory effects in N-metabolism during the experiment. In line, a shift in AA utilization was observed (a higher Lys flow out of plasma in LH pigs, possibly due to increased protein synthesis for deposition in LH-ADEQ pigs, and an increased oxidation of unbalanced Lys in LH-DEF pigs). Our results suggest that partitioning and utilization of AA is affected by the degree of immune system activation, thus health status of pigs.