Association between Rumen Microbiota and Marbling Score in Korean Native Beef Cattle.

Minseok Kim,Hyun-Jeong Lee,Jin Young Jeong,Tansol Park,Youlchang Baek

doi:10.3390/ani10040712

Abstract

Simple SummaryThe ruminal microbiome affects various metabolic processes associated with animal development; however, few studies have focused on its correlation with marbling. Results of the present study show differences in ruminal microbiomes among Hanwoo Korean beef cattle, which have low or high marbling scores. By elucidating the effect of the ruminal microbiome on the marbling of Hanwoo, differentially abundant microbial taxa, ruminal taxonomic drivers of lipid metabolism, and the correlation with meat quality indices, the present study provides insights into the potential effects of microbial factors on marbling in beef cattle.This study demonstrated the potential effects of the rumen microbiota on the deposition of intramuscular fat, known as marbling. Previous studies on fatty acid metabolism in beef cattle have mostly focused on biohydrogenating rumen bacteria, whereas those on the overall rumen microbiota—to understand their roles in marbling—have not been systematically performed. The rumen microbiota of 14 Korean beef cattle (Hanwoo), which showed similar carcass characteristics and blood metabolites but different marbling scores, were analyzed by 16S rRNA gene sequencing. The rumen samples were grouped into two extreme marbling score groups of host animals as follows: LMS, marbling score≤ 4 or HMS, marbling score ≥7. Species richness tended to be higher in the HMS group, whereas the overall microbiota differed between LMS and HMS groups. RFP12, Verrucomicrobia, Oscillospira, Porphyromonadaceae, and Paludibacter were differentially abundant in the HMS group, whereas Olsenella was abundant in the LMS group. Some marbling-associated bacterial taxa also contributed to the enrichment of two lipid metabolic pathways including “alpha-linolenic acid metabolism” and “fatty acid biosynthesis” in the HMS microbiome. Taxonomic drivers of fatty acid biosynthesis, particularly in the rumen microbiome of high-marbled meat, could thus be further studied to increase the intramuscular fat content.

Highlights

In the beef industry, in Korea and Japan, producers have attempted to increase intramuscular fat
Previous reports identified some rumen microbial taxa associated with fatty acid composition in the subcutaneous fat of steers fed different diets [28,29]. These results demonstrated the potential effect of the rumen microbiome on fatty acid metabolism in adipose tissue; correlations between intramuscular fat differentiation or marbling score and microbial factors remain unclear
Principal coordinates analysis (PCoA) based on the unweighted UniFrac distance matrices showed different overall microbiota between the low marbling score (LMS) and high marbling score (HMS) groups, but computing these values based on taxa abundances offset the significance (Figure 1)

Summary

Introduction

In Korea and Japan, producers have attempted to increase intramuscular fat. Intramuscular fat, known as “marbling,” is highly correlated with meat quality traits (e.g., flavor, tenderness, and juiciness); producers require higher marbling scores to achieve greater economic benefits. By using genetic approaches to detect single-nucleotide polymorphisms potentially related to meat quality [4,5,6], many researchers have attempted to increase marbling in beef. Other dietary interventions have been introduced, such as excluding vitamin A supplementation [12,13] and high-grain diet feeding, at early ages [14,15,16,17,18]. Few studies have evaluated the rumen microbiota and its relationship with marbling or meat quality

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Discussion

Conclusion