Frontiers in Microbiology (May 2024)

Effects of different dietary energy levels on growth performance, meat quality and nutritional composition, rumen fermentation parameters, and rumen microbiota of fattening Angus steers

  • Kaihao Chen,
  • Yanghaoer Shui,
  • Ming Deng,
  • Ming Deng,
  • Ming Deng,
  • Yongqing Guo,
  • Yongqing Guo,
  • Yongqing Guo,
  • Baoli Sun,
  • Baoli Sun,
  • Baoli Sun,
  • Guangbin Liu,
  • Guangbin Liu,
  • Guangbin Liu,
  • Dewu Liu,
  • Dewu Liu,
  • Dewu Liu,
  • Yaokun Li,
  • Yaokun Li,
  • Yaokun Li

DOI
https://doi.org/10.3389/fmicb.2024.1378073
Journal volume & issue
Vol. 15

Abstract

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This study investigates the effects of varying energy levels in diets on Black Angus steers, focusing on growth performance, muscle composition, rumen microbial community, and their interrelationships. Twenty-seven Black Angus steers, aged approximately 22 months and weighing 520 ± 40 kilograms, were randomly divided into three groups: low-energy (LE), medium-energy (ME), and high-energy (HE). Each group consisted of nine individuals. The steers were fed diets with energy levels of 6.657 MJ/kg (LE), 7.323 MJ/kg (ME), and 7.990 MJ/kg (HE) following a 14-day pre-feeding period, with a subsequent 90-day main experimental phase. After the 90-day feeding period, both the HE and ME groups exhibited significantly higher average daily weight gain (ADG) compared to the LE group (p < 0.05). The feed-to-weight ratios were lower in the HE and ME groups compared to the LE group (p < 0.05). The HE group showed significantly higher crude fat content in the longissimus dorsi muscle compared to the LE group (p < 0.05), with total fatty acid content in the muscle surpassing that in the ME and LE groups (p < 0.05). As dietary energy levels increased, the diversity of the rumen microbial community decreased (p < 0.05), and significant differences in bacterial community structure were observed between the LE and HE groups (p < 0.05). The results suggest that higher dietary energy levels enhance growth performance and alter muscle composition in Black Angus steers, while also influencing the rumen microbial community. This study contributes to understanding optimal dietary strategies for finishing Angus cattle to improve beef quality, economic returns, and the development of standardized production procedures.

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