Requirement of Ileal Digestible Lysine for European Growing and Finishing Pigs under Tropical Conditions

Abstract

Thirty crossbred barrows averaging 24 kg body weight (BW) were used to investigate the ileal digestible lysine requirement of growing (20-40 and 40-65 kg BW) and finishing pigs (65-90 kg BW). Basal diets based on broken rice, rice bran and peanut meal were fortified with four incremental additions of L-lysine-HCl with an interval of 0.15 %. The dietary lysine contents ranging from 0.65 to 1.25 % for period 20-40 kg, 0.55 to 1.15 % for period 40-65 kg and 0.50 to 1.10 % for period 65-90 kg. Conventional control diets, containing 18.8, 16.4 and 13.8 % crude protein (CP) were also included. Daily gain, N retention , plasma urea nitrogen (PUN) during each of the 17 day balance were measured. Increasing dietary lysine content improved daily gain and protein deposition significantly (p < 0.05) for the growing periods but did not significantly affect in the finishing period. Conversely, the concentration of PUN decreased as dietary lysine concentration increased. Broken-line regression analysis determined the total dietary lysine requirements needed to optimize the daily gain, N retention and PUN as being 11.1, 16.8 and 20.0 g/d for the three stages of growth, respectively. Based on the ileal digestible lysine in feedstuffs and the total lysine contents found to optimize performance, the ileal digestible lysine requirements of European growing and finishing pigs under tropical conditions were 9.9, 15.2 and 17.0 g/d, respectively.