Production attributes of Merino sheep genetically divergent for wool growth are reflected in differing rumen microbiotas

De Barbieri I., Gulino L., Hegarty R.S., Oddy V.H., Maguire A., Li L., Klieve, A.V and Ouwerkerk D. (2015) Production attributes of Merino sheep genetically divergent for wool growth are reflected in differing rumen microbiotas. Livestock Science, 178 119-129. doi:10.1016/j.livsci.2015.05.023


Author De Barbieri I.
Gulino L.
Hegarty R.S.
Oddy V.H.
Maguire A.
Li L.
Klieve, A.V
Ouwerkerk D.
Title Production attributes of Merino sheep genetically divergent for wool growth are reflected in differing rumen microbiotas
Journal name Livestock Science   Check publisher's open access policy
ISSN 1871-1413
Publication date 2015-08
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.livsci.2015.05.023
Open Access Status Not yet assessed
Volume 178
Start page 119
End page 129
Total pages 11
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2016
Language eng
Formatted abstract
Divergent genetic selection for wool growth as a single trait has led to major changes in sheep physiology and metabolism, including variations in rumen microbial protein production and uptake of α-amino nitrogen in portal blood. This study was conducted to determine if sheep with different genetic merit for wool growth exhibit distinct rumen bacterial diversity. Eighteen Merino wethers were separated into groups of contrasting genetic merit for clean fleece weight (CFW; low: WG− and high: WG+) and fed a blend of oaten and lucerne chaff diet at two levels of intake (LOI; 1 or 1.5 times maintenance energy requirements) for two seven-week periods in a crossover design. Bacterial diversity in rumen fluid collected by esophageal intubation was characterized using 454 amplicon pyrosequencing of the V3/V4 regions of the 16S rRNA gene. Bacterial diversity estimated by Phylogenetic distance, Chao1 and observed species did not differ significantly with CFW or LOI; however, the Shannon diversity index differed (P=0.04) between WG+ (7.67) and WG− sheep (8.02). WG+ animals had a higher (P=0.03) proportion of Bacteroidetes (71.9% vs 66.5%) and a lower (P=0.04) proportion of Firmicutes (26.6% vs 31.6%) than WG− animals. Twenty-four specific operational taxonomic units (OTUs), belonging to the Firmicutes and Bacteroidetes phyla, were shared among all the samples, whereas specific OTUs varied significantly in presence/abundance (P<0.05) between wool genotypes and 50 varied (P<0.05) with LOI. It appears that genetic selection for fleece weight is associated with differences in rumen bacterial diversity that persist across different feeding levels. Moderate correlations between seven continuous traits, such as methane production or microbial protein production, and the presence and abundance of 17 OTUs were found, indicating scope for targeted modification of the microbiome to improve the energetic efficiency of rumen microbial synthesis and reduce the greenhouse gas footprint of ruminants.
Keyword Wool genotype
Bacterial communities
Level of intake
QIIME
Rumen ecology
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Queensland Alliance for Agriculture and Food Innovation
Official 2016 Collection
 
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