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Exogenous enzymes have been integral to swine diets for decades, enhancing nutrient availability and improving animal performance. Among these enzymes, proteases have gained attention for their potential to hydrolyze protein sources that endogenous enzymes cannot effectively break down. This study investigates the impacts of aspartic protease and neutral serine protease on the growth performance, carcass characteristics, nutrient digestibility, blood parameters, salivary cortisol levels, and economic viability of pigs during the growing and finishing phases.
Methods: A total of 135 pigs were housed in a randomized block design, divided into five treatment groups with nine replications each. The experimental diets included a positive control (PC) with a 5.0% reduction in protein and amino acid requirements; negative control (NC) with a 7.5% reduction in protein and amino acid requirements; NC + 100 g/mT of aspartic protease (NC100); NC + 150 g/mT of aspartic protease (NC150); and NC + 200 g/mT of serine protease EC 3.4.23.18 (NC200). The experimental period was 104 days and was divided into four periods according to feed changes and nutritional phases: growth 1, 1–26 days; growth 2, 27–49 days; finishing 1, 50–75 days; and finishing 2, 76–104 days.
Results: The inclusion of protease, independently of the source and amount, increased the average daily weight gain of animals compared with the control treatments (PC and NC), improved feed conversion in early stages, and improved diet digestibility compared with 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. Importantly, there were no significant changes in blood parameters or salivary cortisol levels, indicating that the use of aspartic proteases can improve pig performance without adversely affecting stress levels.
Conclusion: Therefore, incorporating aspartic proteases into pig diets is recommended to enhance growth and optimize pork production.
da Cruz, T. A., Donatelli Muro, B. B., Machado Costa Lima, E., Dos Santos Moreira, V., de Carvalho, J. C. C., Pospissil Garbossa, C. A., & Batista Costa, L. (2024). Aspartic protease supplementation enhancing the performance, carcass characteristics, nutrient digestibility and economic viability, without changing blood parameters and salivary cortisol of pigs. Scientific reports, 14(1), 11238. https://doi.org/10.1038/s41598-024-62006-1
