02263naa a2200337 a 450000100080000000500110000800800410001902200320006002400430009210000150013524501030015026000090025350001030026252012120036565000120157765000100158965000190159965300230161865300240164165300240166565300240168965300300171365300290174370000110177270000160178370000180179970000180181770000150183570000160185077300590186610527672018-09-25       2015    bl uuuu     u00u1 u    #d  a1836-0939; eISSN: 1836-57877 ahttp://dx.doi.org/10.1071/AN133662DOI1 aGODWIN, I.  aThe effects of chronic nitrate supplementation on erythrocytic methaemoglobin reduction in cattle.  c2015  aArticle history: Received 2 September 2013, accepted 6 February 2014, published online 8 May 2014.  aAbstract: Calcium nitrate and urea were fed as a supplement on an isonitrogenous basis to Angus steers and their erythrocytic methaemoglobin concentrations and NADH- and NADPH-methaemoglobin reductase levels were measured over a 54-day period. Methaemoglobin concentrations remained elevated despite increases in NADH-methaemoglobin reductase activity. In a second experiment, Brahman cross steers were fed either calcium nitrate or urea supplements for 111 days. Blood cells were then taken, washed and exposed to sodium nitrite to convert all haemoglobin to methaemoglobin. The rates of glycolysis and methaemoglobin reduction were measured following incubation of these cells in buffers containing 1, 5 or 10 mM inorganic phosphate. Glucose consumption and methaemoglobin reduction were increased by inorganic phosphate and were more rapid in those animals supplemented with nitrate. Lactate production of erythrocytes was reduced in those animals fed nitrate. It is concluded that adaptation to chronic nitrite exposure occurs in the erythron, resulting in greater methaemoglobin reduction potential and that there is competition between NADH-methaemoglobin reductase and lactate dehydrogenase for NADH.  aBOVINOS  aDIETA  aSUPLEMENTACION  aEMISIONES DE GASES  aEMISIONES DE METANO  aFOSFATO INORGÁNICO  aINORGANIC PHOSPHATE  aMETAHEMOGLOBINA REDUCTASA  aMETHAEMOGLOBIN REDUCTASE1 aLI, L.1 aLUIJBEN, K.1 aOELBRANDT, N.1 aVELAZCO, J.I.1 aMILLER, J.1 aHEGARTY, R.  tAnimal Production Science, 2015gv. 55(5), p. 611-616.