Enhancing the performance, carcass characteristics, diet digestibility, and economic viability of pigs in the growing and finishing phases through aspartic protease supplementation: a comprehensive evaluation

The objective of this study was to evaluate the performance, carcass characteristics, diet digestibility, blood parameters, salivary cortisol levels, and economic viability of pigs administered aspartic protease during the growing and finishing phases. A total of 130 pigs (age, 63 days ± 1; and average weight, 25.56 ± 0.037 kg) were housed in pens in a randomized block design (initial weight and gender). Five treatment protocols were developed and nine replications per treatment were performed. The experimental diets were positive control (PC), according to the recommendations of Rostagno et al. (2017), with a 5.0% reduction in protein and amino acid requirements; negative control (NC), according to the recommendations of Rostagno et al. (2017), with a 7.5% reduction in protein and amino acid requirements; NC + 100 g/ton of aspartic protease (NC100); NC + 150 g/ton of Aspartic protease (NC150); and NC + 200 g/ton of another protease (NC200). The inclusion of protease, independent of the source and amount, increased the daily weight gain (P < 0.05) of animals compared to treatment with the controls, improved feed conversion (P < 0.05) in some phases, and improved diet digestibility (P < 0.05) compared to the PC. Treatment with NC150 and NC200 resulted in greater carcass weights than treatment with the PC. NC100 led to a greater carcass yield than PC, and NC150 resulted in a greater loin eye area than PC. No differences (P > 0.05) in the blood parameters or salivary cortisol levels were found among the treatment groups. Regarding economic viability, the use of protease increased the profitability of production, with NC150 leading to the best results. Thus, the use of aspartic proteases is recommended to improve performance and effectively facilitate pork production.