An initial investigation on rumen fermentation pattern and methane emission of sheep offered diets containing urea or nitrate as the nitrogen source
L. Li A , J. Davis B , J. Nolan A and R. Hegarty A CA School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
B Milne AgriGroup, 103–105 Welshpool Road, Welshpool, WA 6106, Australia.
C Corresponding author. Email: roger.hegarty@une.edu.au
Animal Production Science 52(7) 653-658 https://doi.org/10.1071/AN11254
Submitted: 24 October 2011 Accepted: 12 January 2012 Published: 20 March 2012
Abstract
The effects of dietary nitrate and of urea on rumen fermentation pattern and enteric methane production were investigated using 4-month-old ewe lambs. Ten lambs were allocated into two groups (n = 5) and each group was offered one of two isonitrogenous and isoenergetic diets containing either 1.5% urea (T1) or 3% calcium nitrate (T2). Methane production was estimated using open-circuit respiration chambers after 6 weeks of feeding. No difference in nitrogen (N) balance, apparent digestibility of N or microbial N outflow existed between treatments (P > 0.05). Animals offered the T2 diet lost less energy through methane than did those fed the T1 diet (P < 0.05). Total volatile fatty acid concentration, molar proportion of propionate, and the molar ratio of acetate to propionate in rumen fluid were not affected by dietary N source. Compared with urea inclusion, nitrate inclusion caused a significantly higher acetate and lower butyrate percentage in rumen volatile fatty acid. Nitrate supplementation tended to lower methane production by ~7.7 L/day relative to urea supplementation (P = 0.06). Methane yield (L/kg DM intake) was reduced (P < 0.05) by 35.4% when 1.5% urea was replaced by 3% calcium nitrate in the diet. Emission intensity (L methane/kg liveweight gain) was ~17.3% lower in the nitrate-supplemented sheep when compared with urea-fed sheep; however, the reduction was not statistically significant (P > 0.05). This study confirms that the presence of nitrate in the diet inhibits enteric methane production. As no clinical symptoms of nitrite toxicity were observed and sheep receiving nitrate-supplemented diet had similar growth to those consuming urea-supplemented diet, it is concluded that 3% calcium nitrate can replace 1.5% urea as a means of meeting ruminal N requirements and of reducing enteric methane emissions from sheep, provided animals are acclimated to nitrate gradually.
Additional keywords: feed intake, liveweight gain, methaemoglobin, rumen volatile fatty acid concentration.
References
Alexander M, Army TJ, de Serres FJ, Frink CR (1972) Accumulation of nitrate. In ‘Hazards of nitrate, nitrite and nitrosamines to man and livestock’. (Eds M Alexander, TJ Army, FJ deSerres and CR Frink) pp. 1–95. (National Academy of Sciences: Washington, DC)Bird SH, Hegarty RS, Woodgate R (2008) Persistence of defaunation effects on digestion and methane production in ewes. Australian Journal of Experimental Agriculture 48, 152–155.
| Persistence of defaunation effects on digestion and methane production in ewes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXovFSg&md5=20374474c2f7f730c2f5956b47814cafCAS |
Blaxter KL, Clapperton JL (1965) Prediction of the amount of methane produced by ruminants. The British Journal of Nutrition 19, 511–522.
| Prediction of the amount of methane produced by ruminants.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF28XitFKktg%3D%3D&md5=8333eec84be939ab0d38bc4ae189f3e6CAS |
Brouwer E (1965) Report of sub-committee on constants and factors. In ‘Third symposium energy metabolism. (Ed. KL Blaxterd) pp. 441–443. (European Association of Animal Production: London, UK)
Bruning-Fann CS, Kaneene JB (1993) The effects of nitrate, nitrite, and N-nitroso compounds on animal health. Veterinary and Human Toxicology 35, 237–253.
Chen XB, Chen YK, Franklin MF, Ørskov ER, Shand WJ (1992) The effect of feed intake and body weight on purine derivative excretion and microbial protein supply in sheep. Journal of Animal Science 70, 1534–1542.
Cheng KL, Phillippe RC, Kozub GC, Majak W, Costerton JW (1985) Induction of nitrate and nitrite metabolism in bovine rumen fluid and the transfer of this capacity to untreated animals. Canadian Journal of Animal Science 65, 647–652.
| Induction of nitrate and nitrite metabolism in bovine rumen fluid and the transfer of this capacity to untreated animals.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXmtFWqtLY%3D&md5=ef7f1b32f7e1eb38e4992ef5ea009993CAS |
Clark JL, Pfander WH, Bloomfield RA, Krause GF, Thompson GB (1970) Nitrate containing rations for cattle supplemented with either urea or soybean meal. Journal of Animal Science 31, 961–966.
Cockrum R, Austin K, Ludden P, Cammack K (2008) Effects of elevated dietary nitrate on production and reproduction parameters in Suffolk ewes. American Society of Animal Science 59, 332–335.
Entwistle KW, Knights G (1974) The use of urea-molasses supplements for sheep grazing semi-arid tropical pastures. Australian Journal of Experimental Agriculture and Animal Husbandry 14, 17–22.
| The use of urea-molasses supplements for sheep grazing semi-arid tropical pastures.Crossref | GoogleScholarGoogle Scholar |
Farrell R, Knights G (2001) ‘Livestock nutrition – supplementary feeding using the Toorak urea block.’ (Primary Industries and Fisheries, Queensland Government: Brisbane) Available at http://www2.dpi.qld.gov.au/sheep/8073.html [Verified 29 February 2012]
Guo WS, Schaefer DM, Guo XX, Ren LP, Meng QX (2009) Use of nitrate-nitrogen as a sole dietary nitrogen source to inhibit ruminal methanogenesis and to improve microbial nitrogen synthesis in vitro. Asian-Australian Journal of Animal Science 22, 542–549.
Hegesh E, Gruener N, Cohen S, Bochkovskf R, Shuval HI (1970) A sensitive micromethod for the determination of methaemoglobin in blood. Clinica Chimica Acta 30, 679–682.
| A sensitive micromethod for the determination of methaemoglobin in blood.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE3MXltVCjtA%3D%3D&md5=cfe4262621e26c226546c4406e112bd3CAS |
Huyen LTN, Do HQ, Preston TR, Leng RA (2010) Nitrate as fermentable nitrogen supplement to reduce rumen methane production. In ‘Livestock research for rural development’. (Eds TR Preston, R Sansoucy, JS Correa and H Osorio) (Fundación CIPAV: Cali, Colombia) Available at http://www.lrrd.org/lrrd22/8/huye22146.htm [Verified 2 March 2011]
IAEA (1997) ‘Estimation of rumen microbial protein production from purine derivatives in urine.’ (INIS Clearinghouse, IAEA: Vienna, Austria) Available at http://www.iaea.org/programmes/nafa/d3/public/tecdoc-945.pdf [Verified January 2010]
Johnson DE, Ward GM (1996) Estimates of animal methane emissions. Environmental Monitoring and Assessment 42, 133–141.
| Estimates of animal methane emissions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28Xltlars7s%3D&md5=1915d1c9171ff44a10b96fbdc1f1646fCAS |
Leng RA (2010) Further considerations of the potential of nitrate as a high affinity electron acceptor to lower enteric methane production in ruminants. In ‘International conference on livestock, climate change and resource depletion’. (Eds R Preston, B Ogle) pp. 9–11. (Champasack University: Pakse, Laos)
McCrabb GJ, Hunter RA (1999) Prediction of methane emissions from beef cattle in tropical production systems. Australian Journal of Agricultural Research 50, 1335–1339.
| Prediction of methane emissions from beef cattle in tropical production systems.Crossref | GoogleScholarGoogle Scholar |
NGGI (2009) ‘National greenhouse gas inventory.’ (Australian Government, Department of Climate Change: Canberra)
Nguyen NA, Khuc TH, Duong NK, Preston TR (2010) Effect of calcium nitrate as NPN source on growth performance and methane emissions of goats fed sugar cane supplemented with cassava foliage. In ‘Mekarn conference on livestock production, climate change and resource depletion’. (Eds TR Preston, B Ogle) (Pakes, Laos)
Nolan JV, Hegarty RS, Hegarty J, Godwin IR, Woodgate R (2010) Effects of dietary nitrate on fermentation, methane production and digesta kinetics in sheep. Animal Production Science 50, 801–806.
| Effects of dietary nitrate on fermentation, methane production and digesta kinetics in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtVyrtbzP&md5=e53924d36a18c6f2476bd0a971faf317CAS |
SheepExplorer (2003) The excel spreadsheet SheepExplorer of GRAZPLAN. Available at http://www.pi.csiro.au/grazplan/ [Accessed April 2005]
Sinclair KB, Jones DIH (1964) Nitrate toxicity in sheep. Journal of the Science of Food and Agriculture 15, 717–721.
| Nitrate toxicity in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF2MXjt1GrsQ%3D%3D&md5=4d2dc7e8e7517843479d03ea443bf9afCAS |
van Zijderveld SM, Gerrits WJJ, Apajalahti JA, Newbold JR, Dijkstra J, Leng RA, Perdok HB (2010) Nitrate and sulfate: effective alternative hydrogen sinks for mitigation of ruminal methane production in sheep. Journal of Dairy Science 93, 5856–5866.
| Nitrate and sulfate: effective alternative hydrogen sinks for mitigation of ruminal methane production in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjs1Kis7Y%3D&md5=e585a62414dc9632ec27af5402a74b9bCAS |
Warner ACI (1962) Some factors influencing the rumen microbial population. Journal of General Microbiology 28, 129–146.
