Application of aspartate protease and neutral serine protease

Adding aspartic protease to the growth and finishing diet can improve the performance and carcass quality of pigs.

Exogenous enzymes have always been an indispensable part of pig diets, which can improve nutrient utilization and improve animal performance.

Among these enzymes, the potential of exogenous proteases has been the focus of attention because of their ability to hydrolyze some proteins that cannot be effectively broken down by endogenous enzymes.

This ability is not only important for improving protein availability, but is also needed to mitigate the effects of anti-nutrient factors in protein sources and reduce nitrogen emissions.

This study investigated the effects of aspartate protease and neutral serine protease on growth performance, carcass characteristics, nutrient digestibility, blood parameters and salivary cortisol levels in pigs during growth and finishing stages.

Experimental design

A total of 135 pigs were randomized into 5 treatment groups with 9 replicates per group.

• The experimental diet included a positive control (PC) with a 5.0% reduction in protein and amino acid requirements;
• Negative control (NC), protein and amino acid requirements decreased by 7.5%;
• NC+100g/mT aspartate protease (NC100);
• NC+150g/mT aspartate protease (NC150);
• NC+200g/mT serine protease EC 3.4.23.18 (NC200);

The trial lasted 104 days and was divided into four periods based on feed changes and nutrient stages:

• Growth period 1, 1-26 days;
• Growing period 2, 27-49 days;
• Growing period 1, 50-75 days;
• Growing period: 2, 76-104 days.

The addition of proteases (regardless of source and amount) increased the average daily gain of the animals compared to both positive (PC) and negative (NC) control treatments.

Compared with PC, the addition of protease increased the early feed conversion rate and increased the dietary digestibility.

A comparison of the NC150 and NC200 (serine protease EC 3.4.23.18) treatment groups with the PC treatment group showed a significant increase in carcass weight.

Higher carcass yields were also observed in the NC100 treatment group compared to the PC treatment group.

In addition, larger lumbar eye area was observed in the NC150 treatment group compared to the PC treatment group.

Importantly, there were no significant changes in blood parameters or salivary cortisol levels, suggesting that the use of aspartic protease and serine protease could improve pig performance without causing changes in stress levels.

Therefore, aspartate protease and serine protease can be added to pig diets to promote growth and optimize pork production.