Effects of dietary nitrate on fermentation, methane production and digesta kinetics in sheep

The effects of dietary nitrate on DM digestion, rumen volatile fatty acid concentrations, microbial protein outflow, rumen water kinetics, and methane production were studied. Eight rumen-cannulated sheep were acclimated to a diet consisting of chaffed oaten hay supplemented with either 4% KNO₃ or 0...

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Bibliographic Details
Published inAnimal production science Vol. 50; no. 8; pp. 801 - 806
Main Authors Nolan, J.V, Hegarty, R.S, Hegarty, J, Godwin, I.R, Woodgate, R
Format Journal Article
LanguageEnglish
Published Collingwood, Victoria: CSIRO Publishing 2010
Subjects
animal performance
chaff
chaffed oaten hay
digestibility
feed supplements
gas production (biological)
hay
in vitro digestibility
kinetics
methane
nonprotein nitrogen
oats
optimal nutrition
potassium nitrate
protein supplements
rumen fermentation
rumen microorganisms
sheep
sheep feeding
urea
volatile fatty acids
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Summary:The effects of dietary nitrate on DM digestion, rumen volatile fatty acid concentrations, microbial protein outflow, rumen water kinetics, and methane production were studied. Eight rumen-cannulated sheep were acclimated to a diet consisting of chaffed oaten hay supplemented with either 4% KNO₃ or 0% KNO₃ but made iso-nitrogenous by the addition of urea. Nitrate supplementation did not affect blood methaemoglobin concentration, DM intake, whole tract or ruminal DM digestibility and the sheep appeared healthy at all times throughout the acclimation and experimental periods. Nitrate did cause changes in rumen fermentation consistent with its acting as a high-affinity hydrogen acceptor, i.e. there was a tendency towards a lower molar percentage of propionate in the rumen volatile fatty acids, and higher molar ratio of acetate to propionate. Methane yield (MY, L methane/kg DM intake) was reduced by 23% in KNO₃-supplemented sheep (P < 0.05) and these sheep tended to have a shorter mean fluid retention time in the rumen (MRT). There was a significant association between MRT and MY, such that a shorter MRT was associated with a lower MY. The results confirmed that the presence of nitrate in the diet lowers enteric methane production even though there was considerable between-animal variation in gut kinetics and methane production.
Bibliography:http://dx.doi.org/10.1071/AN09211
ISSN:1836-0939
DOI:10.1071/AN09211