Journal of Animal Science and Technology
Korean Society of Animal Science and Technology

Comparative effects of proteases on performance, carcass traits and gut structure of broilers fed diets reduced in protein and amino acids

Alexandra Wealleans, Roba Ashour, Majdi Abu Ishmais, Sadiq Al-Amaireh, David Gonzalez-Sanchez*
1KEMIN Animal Nutrition and Health, Herentals 2200, Belgium.
2KEMIN Animal Nutrition and Health, Herentals 2200, Belgium.
3Department of Animal Production, Faculty of Agriculture, Jordan University of Science and Technology, Irbid 22110, Jordan.
4Suliman Al-Amaireh & Partners Co, Tabarbor, Amman 11731, Jordan.
5KEMIN Animal Nutrition and Health, Herentals 2200, Belgium.
*Corresponding Author: David Gonzalez-Sanchez, E-mail: DAVID.GONZALEZSANCHEZ@KEMIN.COM.

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Oct 13, 2022; Revised: Nov 21, 2022; Accepted: Feb 19, 2023

Published Online: Feb 20, 2023


This study aimed to evaluate the effect of supplementing different protease enzymes on growth performance, intestinal morphology, and selected carcass traits in broilers fed diets reduced 3.5% in crude protein (CP) and amino acids (AA). One thousand one-day-old Ross 308 broilers (41 g) were assigned to five dietary treatments with ten replicates of 20 birds each: (PC) a positive control diet formulated to meet Ross 308 amino acid requirements, (NC) a negative control diet reformulated to provide 3.5% lower CP and AA compared to PC, (PR1) NC supplemented with a multi-protease solution, containing 3 different coated proteases produced from <italic>Aspergillus niger, Bacillus subtilis</italic> and <italic>Bacillus licheniformis</italic>, (PR2) NC supplemented with a serine protease produced from <italic>Bacillus licheniformis</italic>, and (PR3) NC supplemented with an alkaline protease produced from <italic>Bacillus licheniformis</italic>. At slaughter, 40 birds per treatment were used to assess the effect of the different treatments on carcass traits. At 32 days, samples of the duodenum, jejunum, and ileum of 10 birds per treatment were collected for intestinal morphology evaluation. Birds fed PC and NC supplemented with multi-protease exhibited better (<italic>p</italic> &lt; 0.05) feed efficiency compared to NC and NC supplemented with all the other protease enzymes. Multi-protease supplementation was linked to the highest (<italic>p</italic> &lt; 0.05) carcass weight and yield. There were significant differences (<italic>p</italic> &lt; 0.05) between treatments in all gut segments, with PC, PR1, PR2, and PR3 exhibiting longer villi height (VH) compared to NC. This study demonstrates that 3.5% reduction of CP and AA negatively affected for the overall period feed efficiency, carcass yield, and intestinal morphology. The supplementation of the multi-protease restored feed efficiency and improved carcass yield.   

Keywords: broiler; protease enzyme; growth performance; gut morphology; carcass trait