Far-infrared ray and β-mannanase influence on growth performance, meat quality, gut morphology, and blood parameters in nutritionally challenged broilers

Jeseok Lee¹, Sehyeok Oh¹, Elijah Oketch¹, Shan Nawarathne¹, Nuwan Chaturanga¹, Haeeun Park¹, Taichang Hur², Myunghwan Yu³^,^*, Jung Min Heo¹^,^**

¹Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 34134, Korea.

²Cereswaves Korea Co. LTD., Changwon 51787, Korea.

³Poultry Research Center, Department of Animal Resource Development, National Institute of Animal Science, Rural Development Administration, Pyeongchang 25342, Korea.

^**Corresponding Author: Myunghwan Yu, Poultry Research Center, Department of Animal Resource Development, National Institute of Animal Science, Rural Development Administration, Pyeongchang 25342, Korea, Republic of. E-mail: tomymh@korea.kr.

^**Corresponding Author: Jung Min Heo, Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 34134, Korea, Republic of. E-mail: jmheo@cnu.ac.kr.

© Copyright 2025 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 (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Jul 29, 2025; Revised: Sep 09, 2025; Accepted: Oct 23, 2025

Published Online: Nov 03, 2025

Abstract

This study investigated the effects of far-infrared ray (FIR) radiation on broiler performance, carcass traits, meat quality, intestinal morphology, and blood metabolites in birds fed different energy and amino acid (EAA) levels with or without β-mannanase from hatch to day 35. A total of 384 one-day-old Ross 308 broilers were assigned to a 2 × 2 × 2 factorial design: FIR radiation (yes or no), dietary EAA level (normal or low), and β-mannanase supplementation (yes or no). Data were analyzed using three-way ANOVA to evaluate the main and interactive effects of these factors, with Tukey’s test applied for multiple comparisons. FIR exposure improved (<italic>p</italic> < 0.001) average daily gain (ADG) and average daily feed intake (ADFI) on days 1–35. Feed conversion ratio (FCR) was reduced (<italic>p</italic> < 0.05) on days 1–10, 11–21, and overall. FIR combined with β-mannanase enhanced (<italic>p</italic> < 0.001) ADG on days 1–10 and 11–21. Broilers fed a low EAA diet and exposed to FIR had higher (<italic>p</italic> < 0.01) ADFI on days 1–10. On day 35, FIR increased (<italic>p</italic> < 0.001) moisture, crude protein, and ash content in breast meat and improved (<italic>p</italic> < 0.05) relative breast meat weight. FIR also enhanced (<italic>p</italic> < 0.01) water-holding capacity and pH, while reducing (<italic>p</italic> < 0.05) cooking loss. FIR improved intestinal morphology by increasing (<italic>p</italic> < 0.001) villus height on days 21 and 35. A significant three-way interaction (<italic>p</italic> < 0.01) among FIR, EAA level, and β-mannanase was observed for villus height on day 21. Immunologically, FIR reduced (<italic>p</italic> < 0.01) blood levels of IL-1β and TNF-α on days 21 and 35 and IFN-γ on day 35. FIR also lowered (<italic>p</italic> < 0.05) blood glucose and lactate levels on both days. In conclusion, FIR radiation, particularly under nutrient-challenged conditions, enhanced broiler growth performance, carcass yield, meat quality, and immune status, with β-mannanase providing additional early growth benefits. FIR technology shows potential as a non-invasive, feed-independent strategy to improve commercial broiler productivity, warranting further field evaluation.

Keywords: far-infrared ray; β-mannanase; nutrient density; performance; intestinal health