Composition of Fecal Microbiota in Grazing and Feedlot Angus Beef Cattle

Zhimin Zhang,Yang He,Shaokang Zhao,Xinmao Luo,Xianbo Jia,Li Yang

doi:10.3390/ani11113167

Abstract

Simple SummaryThis study is to investigate the difference of bovine fecal microbiota between grazing and feedlot Angus cattle. The fecal bacterial community was analyzed by high-throughput sequencing of 16S rRNA gene from six Angus cattle grazed on grassland and six Angus cattle fed on a feedlot. A total of 775 OTUs were taxonomically assigned to bacterial 12 phyla, 19 classes, 25 orders, 54 families, 141 genera, and 145 species. The dominant phyla were Firmicutes and Bacteroidetes. There was similar species richness between grazing and feedlot Angus beef, while species diversity was higher in feedlot Angus beef. The relative abundance of Firmicutes, Cyanobacteria, Elusimicrobia and Patescibacteria was significantly different between grazing and feedlot Angus beef (p < 0.05). At the genus level, five microbiotas were significantly different microbiotas between the two groups and all belonged to the Firmicutes phylum. These significant differences in microbiota composition between grazing and feedlot Angus beef may have an impact on the meat quality of Angus beef.This study is to investigate the difference in bovine fecal microbiota between grazing and feedlot Angus cattle. Fecal samples were collected from six Angus cattle grazed on grassland and six Angus cattle fed on a feedlot. The fecal bacterial community was analyzed by high-throughput sequencing of 16S rRNA gene. Sequencing of the V3–V4 region totally produced 1,113,170 effective tages that were computationally clustered into 775 operational taxonomic units (OTUs). These 775 OTUs were taxonomically assigned to bacterial 12 phyla, 19 classes, 25 orders, 54 families, 141 genera, and 145 species. The dominant phyla were Firmicutes and Bacteroidetes. There was similar species richness between grazing and feedlot Angus beef, while higher species diversity was observed in feedlot Angus beef. The relative abundance of Firmicutes, Cyanobacteria, Elusimicrobia and Patescibacteria was significantly different between grazing and feedlot Angus beef (p < 0.05). At a genus level, five microbiotas were significantly different between the two groups and all belonged to the Firmicutes phylum. These significant differences in microbiota composition between grazing and feedlot Angus beef may have an impact on the meat quality of Angus beef.

Highlights

IntroductionGrazing-fed cattle are free-ranged on pastures with grass as the main feed, while feedlot-fed cattle are raised in feedlots with grains as their main feed
This study focuses on understanding the fecal microbiota in grazing- and feedlot-fed beef cattle by 16S rRNA sequencing, and searching for key bacterial differences
Six cattle (ANG1~6, group F) were randomly selected from a herd, which was kept in one indoor feedlot and fed with the total mixed ration diet based on corn silage according to the National Research Council (NRC)

Summary

Introduction

Grazing-fed cattle are free-ranged on pastures with grass as the main feed, while feedlot-fed cattle are raised in feedlots with grains as their main feed. The grass is low in energy but high in fiber, on the contrary, grains are high in energy and easy to digest. There are significant differences between the two feeding methods in digestibility, growth rate and meat quality. Compared to feedlot-fed beef, grazing-fed beef has lower fatty acid content and higher vitamin content [1]. Because nowadays people are concerned about energy and nutritional balance, consumers are increasingly favoring grazing-fed beef [2]

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