PSXIII-4 Inosine-5’-monophosphate in reduced metabolizable energy diets fed to finishing gilts subjected to immune stimulation.

Abstract The objective of this study was to investigate the use of inosine-5’-monophosphate (5’-IMP) in reduced metabolizable energy (ME) diets fed to immune stimulated gilts on the performance, carcass traits and meat quality. Forty gilts (75.58 ± 0.94 kg BW) were assigned in a 2 x 2 factorial design, with 10 replicates per treatment. The studied factors consisted of a conventional diet (3,330 kcal ME/kg) or a 5’-IMP-supplemented diet with ME reduction (0.100% 5’-IMP and 3,200 kcal ME/kg), the another factor consisted of immune system stimulation or not. The immune stimulation protocol consisted of inoculating 1 mg bovine serum albumin with 0.5 mL phosphate-buffered saline associated with 0.5 ml Freund’s complete adjuvant (day 1). This same procedure was latter repeated (day 12), but in association with Freund’s incomplete adjuvant, instead of complete adjuvant. Growth performance was measured and, at the end of the experiment (day 24, 101.13 ± 1.99 kg BW), gilts were slaughtered for carcass traits and Longissimus lumborum muscle evaluation. Data were analyzed using ANOVA and least-squares to differentiate the means, considering the effects of diets, immune stimulation and the interaction between diets x immune stimulation. Interaction was observed for average daily gain (P < 0.001), increasing in gilts fed the 5’-IMP diet compared to the ones fed the conventional diet, but only in immune stimulated gilts. The feed conversion was improved in gilts fed the 5’-IMP diet (P < 0.001) and also in non-immune stimulated gilts (P = 0.012). Significative interactions also included increased Longissimus lumborum depth (P = 0.004) and ham weight (P < 0.001) of immune-stimulated gilts. Interaction was observed for P1P2P3 backfat thickness (P = 0.030), reducing in gilts fed the 5’-IMP diet (P = 0.001) at low immune stimulation condition. However, the interaction observed for P1 backfat thickness (P < 0.001) was related to immune stimulation (P = 0.019), observing higher values for immune stimulated gilts receiving the 5’-IMP diet, and the opposite observed for pigs receiving the conventional diet. The 5’-IMP diet, by itself, enhanced the hot (P = 0.022) and cold (P = 0.011) carcass yields, as the lean meat yield (P = 0.012). Interactions indicated better 24-hour pH (P = 0.037), reduced thawing (P = 0.030) and cooking (P < 0.001) losses, and also reduced shear force (P < 0.001) of Longissimus lumborum of gilts fed the 5’-IMP diet, at both immune system conditions. The use of 0.100% 5’-IMP, along with a reduction of 100 kcal ME/kg of feed, was effective in alleviating the energy restriction and also compensates the energy deficit resulting from immune system stimulation, providing benefits in productive performance, carcass traits and meat quality.