DIGESTIBILIDAD ILEAL DE AMINOÁCIDOS Y COMPORTAMIENTO PRODUCTIVO DE CERDOS ALIMENTADOS CON DIETAS A BASE DE TRIGO, ADICIONADAS CON UNA PROTEASA FUNGAL ILEAL DIGESTIBILITY OF AMINO ACIDS AND PERFORMANCE OF PIGS FED WHEAT DIETS, SUPPLEMENTED WITH FUNGAL PROTEASE

Proteolytic exogenous enzymes improve amino acid digestibility and reduce protein waste. To evaluate the effect of adding a fungal protease to wheat-based diets on the apparent ileal digestibility (AID) of amino acids (AA) and the performance of growing pigs, two experiments were conducted. In both, the basal diet contained wheat (Triticum aestivum), 0.55% lysine, 0.10% threonine, vitamins and minerals. In Experiment 1, four pigs with a cannula in ileum were used in two periods, in a crossover design, in a completely randomized blocke design. The treatments were: 1) Basal diet, and 2) basal diet plus 0.3% protease. Both diets contained 0.4% chromic oxide. Feed was mixed with water, and offered twice a day, in equal rations, at 7.00 and 19.00 h, in two 12-d periods; 8 d adaptation to diet and 4 d for digesta collection. This was continuous from 7.00 to 13.00 h (9 and 11 d), and from 13.00 to 19.00 (10 and 12 d). There was not enzyme effect on the AID of AA (p>0.10). In Experiment 2, 28 pigs were grouped based on weight, age, sex and litter, into four treatments, with seven replicates, in a randomized complete blocks design. The treatments were: 1) basal diet; treatments 2, 3, and 4: basal diet plus 0.1, 0.2, and 0.3% protease, respectively. The enzyme did not affect the weight gain, nor feed, lysine, and threonine intake (p>0.10), but deteriorated feed conversion (p=0.016). These results suggest that the addition of protease to wheat-based diets for growing pigs, does not improve pig performance nor apparent ileal digestibility of AA.