Abstract
Antibiotics have been widely used in livestock to treat and prevent bacterial diseases. However, use of antibiotics has led to the emergence of antibiotic resistant microorganisms (ARMs) in food animals. Due to the decreased efficacy of antibiotics, alternatives to antibiotics that can reduce infectious diseases in food animals to enhance animal health and growth performance are urgently required. Here, we show that animal genetics is associated with the hindgut microbiome, which is related to fat deposition and beta-lactam resistance in the gastrointestinal tract. We investigated the hindgut microbiota structure in 95 postweaning heifers belonging to the unique multibreed Angus-Brahman herd with breed composition ranging from 100% Angus to 100% Brahman. The hindgut microbial composition of postweaning heifers differed among breed groups. The mucin-degrading bacterium Akkermansia known for promoting energy expenditure was enriched in Brahman calves that contained less intramuscular fat content, while butyrate-producing bacterium Faecalibacterium was linearly positively correlated with Angus proportion. Moreover, the higher relative abundance of beta-lactam resistant genes including ampC gene and arcA gene was associated with the greater Brahman proportion. As the first study aimed at understanding changes in hindgut microbiota among beef cattle with linear gradient of breed composition and its association with marbling in meat, our results suggest that the effects of animal genetics on the gut microbiota structure is associated with fat deposition and potentially a factor affecting the gut antimicrobial resistance.
Highlights
Antibiotic resistance has become a huge threat to public health as well as one of the major causes of global human mortality over the past few years (Ventola, 2015; Ferri et al, 2017)
To investigate the influence of breed composition on the hindgut microbiota, and the contribution of hindgut microbiota to animal growth, we collected fecal samples from the 95 postweaning multibreed Angus-Brahman (MAB) heifers raised on pasture
Our study investigated the association between breed composition and the hindgut microbiota structure of postweaning heifers and its association with animal growth and possible impact on the antimicrobial resistance profile
Summary
Antibiotic resistance has become a huge threat to public health as well as one of the major causes of global human mortality over the past few years (Ventola, 2015; Ferri et al, 2017). The failure to successfully treat infectious diseases caused by antibiotic resistant microorganisms (ARMs) has resulted in at least 23,000 deaths in the United States annually estimated by the Center for Disease. Antibiotics used in agricultural settings account for 50–80% of the antibiotics produced in the United States to prevent or treat animal diseases (Bartlett et al, 2013; Cully, 2014). The main risks associated with the extensive use of antibiotics in agricultural settings is the spread of antimicrobial resistance among foodproducing animals, transmission into humans through food chains (Thanner et al, 2016). It is urgent to develop alternatives to antibiotics mitigating ARMs in livestock to enhance animal health and growth performance
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