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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #345097
Title: Camelina seed supplementation at two dietary fat levels changes ruminal bacterial community composition in a dual-flow continuous culture system

Author
item DAI, XIAOXIA - University Of Nevada
item Weimer, Paul
item DILL-MCFARLAND, KIMBERLEY - University Of Wisconsin
item BRANDAO, VIRGINIA - University Of Nevada
item SILVA, LUIS - University Of Nevada
item PAULA, EDUARDO - University Of Nevada
item SHENKORU, TESHOME - University Of Nevada
item SUEN, GARRET - University Of Wisconsin
item FACIOLA, ANTONIO - University Of Nevada

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Camelina, a member of the mustard family, is well adapted to different climate and soil types. Camelina seed (CS) is rich in polyunsaturated fatty acids, suggesting that CS could be used as a high-quality lipid supplement for ruminants. However, the high content of certain fatty acids and anti-nutritional contents could change the ruminal fermentation and metabolites through changing ruminal bacterial community compositions. Our study showed that CS supplementation could be energetically beneficial to dairy cows by increasing propionate-producing bacteria and useful at suppressing ruminal bacteria associated with biohydrogenation; however, attention should be given to avoid negative effects of CS supplementation on suppressing cellulolytic bacteria. Our results will be useful to nutritionists and producers who formulate dairy cattle rations.

Technical Abstract: This study sought to determine the effects of camelina seed (CS) supplementation at different dietary fat levels on the ruminal bacterial community composition in dairy cows, and how it relates to changes in ruminal fermentation and metabolism in a dual-flow continuous culture system. Diets were randomly assigned to eight fermenters (1,200-1,250 mL) in a 2 x 2 factorial arrangement of treatments in a replicated 4 x 4 Latin square design with four 10-d experimental periods that consisted of 7 d for diet adaptation and 3 d for sample collection. Treatments were: 1) no CS at 5% ether extract (EE, NCS5); 2) no CS at 8% EE (NCS8); 3) 7.7% camelina seed (CS) at 5% EE (CS5); and 4) 17.7% CS at 8% EE (CS8). Diets contained 55% orchardgrass hay and 45% concentrate, and fermenters were equally fed a total of 72 g/d (DM basis) daily at 0800 and 2000 h. The bacterial community of each sample was determined by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequencing data were analyzed on MOTHUR, and statistical analyses were performed on R and SAS. The most abundant phyla across treatments were Bacteroidetes and Firmicutes, accounting for 49% and 39% of total sequences, respectively. The bacterial community composition in both liquid and solid fractions of the effluent digesta were changed by CS supplementation, but not by dietary EE. Inclusion of CS in the diets decreased the relative abundance of Ruminococcus spp., Fibrobacter spp., and Butyrivibrio spp. The most abundant genus across treatments, Prevotella, was reduced by high dietary EE levels while Megasphaera and Succinivibrio were increased by CS supplementation in the liquid fraction. Correlatively, the concentration of acetate was decreased while propionate was increased; C18:0 was decreased and polyunsaturated fatty acids, especially C18:2 n-6 and C18:3 n-3 were increased by CS supplementation. Based on the correlation analysis between genera and fermentation end-products, this study revealed that CS supplementation could be energetically beneficial to dairy cows by increasing propionate-producing bacteria and useful at suppressing ruminal bacteria associated with biohydrogenation; however, attention should be given to avoid negative effects of CS supplementation on suppressing cellulolytic bacteria.