Abstract

Protein is a source of nutrients that plays a significant role in biological processes. The current study aimed to evaluate the effects of feed with different protein levels on the pH and viscosity of the small intestine, ileum characteristics, and carcass traits of cross-breed chickens. A total of 160 cross-breed unsexed chicks aged 2 days were divided into three treatments (T1-T3), each consisting of 6 replications with 9 chicks per replication, consisting of a diet with protein level (T1; starter 18 and finisher 16;), a diet with protein level (T2; starter 20 and finisher 18), and a diet with protein level (T3; starter 22 and finisher 20). Cross-breed chickens were crossed between Bangkok males and Lohmann laying hens. The variables were analyzed, including pH and viscosity of digesta, ileum characteristics consisting of total villous, height of villous, and depth of crypt. The carcass percentages consisting of the carcass, breast, thicks, wings, and back were measured. The research was analyzed using a completely randomized design. The results indicated that different protein levels in treatments were significantly different in total villous, height of villous, and depth of crypt but did not indicate a significant difference in pH and viscosity. Furthermore, the treatments have a significant difference in the carcass percentage and thick percentage but did not significantly affect the breast, wings, and back. It can be concluded that 22 crude protein in the starter and 20 crude protein in the finisher produced the greatest results in the intestinal characteristics and also in the carcass percentage of cross-breed chickens. © Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.